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Percutaneous angiography of Patent Ductus Arteriosus in dogs: techniques, results and implications for intravascular occlusion
Journal of Veterinary Cardiology, Vol.5, No. 2, November 2003
A new generation ACE inhibitor
Percutaneous angiography of Patent Ductus Arteriosus in dogs: techniques, results and implications for intravascular occlusion
Intervet has been at the forefront of veterinary cardiovascular medicine since 1994, when it launched the first ACE inhibitor for veterinary use.
Matthias Schneider1; Ingo Schneider2; Nicolai Hildebrandt3; Martin Wehner4
This revolutionised the treatment of congestive heart failure in dogs. Intervet is now able to present Vasotop, containing
Abstract
ramipril, the new generation ACE inhibitor, that
Objectives: To evaluate the percutaneous angiography and the morphology of patent ductus arteriosus (PDA) in dogs.
revolutionised human ACE inhibitor therapy. Vasotop: the next step forward for
Background: In contrast to surgical ligation the knowledge of angiographic morphology is necessary for intravascular PDA occlusion.
the treatment of congestive heart failure in dogs.
Young at Heart!
Methods: Forty-nine dogs with a left to right shunting PDA were included in a three-year, prospective study. In 43 dogs with a body weight ≥ 3.0 kg a percutaneous approach to brachial artery was tested. In six miniature dogs (< 3.0 kg) placement of angiographic catheter from femoral vein antegrade through the PDA was studied. Angiographic morphology and dimensions of PDA were analyzed. Results: Percutaneous approach to brachial artery was performed successfully in 41/43 (95%) dogs, in the remaining 2 dogs this approach was not possible and the femoral artery had to be used. Two dogs did not survive the procedure. Arterial bleeding was not a problem in any of the 39 cases in which percutaneous brachial artery catheterization was performed. Two dogs developed transient radial nerve paralysis that resolved 4 to 6 days later. The transvenous technique was successful in all 6 small dogs. In 39 dogs there was an elongated conical duct (type E). A conical duct (type A) was found in nine dogs and one dog had a PDA with two
constrictions (type D). The mean PDA minimal diameter was 3.78 ± 1.55 mm (range 1.5 to 6.9), in 20/49 dogs (41%) the minimal PDA diameter measured more than 4.0 mm. Conclusions: Percutaneous catheterization of the brachial artery using a vascular introducer is feasible and entails minimal risk of hemorrhage. Angiographic evaluation of the ductus arteriosus is easily performed with this technique, but coilimplantation is not possible by this approach. The frequency of PDA-types is different in dogs and humans and the PDA minimal diameter is larger in dogs.
Key words: Dog, patent ductus arteriosus, angiography, catheter, embolization
Patent ductus arteriosus (PDA) is one of the most common congenital heart diseases in dogs. It is treated commonly by surgical ligation or by intravascular occlusion using catheter techniques1-8. Angiography is not routinely performed in dogs undergoing PDA ligation9,10. Consequently, angiographic descriptions of canine PDAs are limited7,9. Knowledge of ductal morphology and dimensions is essential for successful intravascular occlusion. Measures of the minimal PDA diameter are used in human medicine to select the correctly sized embolization system. An angiographic PDA-type
DVM, Dr Med Vet, PD. DVM, Dr Med Vet. 3 DVM. 4 DVM. From the Medical and Forensic Veterinary Clinic, Department of Small Animal Internal Medicine, Justus-Liebig-University of Giessen, Giessen, Germany Short title: Angiography of Patent ductus arteriosus in dogs 1
060844
2
This study was performed at the Medical and Forensic Veterinary Clinic, Department of Small Animal Internal Medicine, Justus-Liebig-University of Giessen, Giessen, Germany Corresponding author: Matthias Schneider, Dr.med.vet., Medizinische und Gerichtliche Veterinärklink I, Innere Krankheiten der Kleintiere, Justus-LiebigUniversity Giessen, Frankfurterstr. 126, D-35392 Giessen, Germany; e-mail: [email protected]
Intervet International bv • P.O. Box 31 • 5830 AA Boxmeer • The Netherlands Phone: +31 485 587600 • Fax: +31 485 577333 • E-mail: [email protected] • www.intervet.com
21
Matthias Schneider; Ingo Schneider; Nicolai Hildebrandt; Martin Wehner classification scheme has been proposed by Krichenko and colleagues11. Adaptations of the human classification systems7 as well as a specifically designed veterinary classification system12 have recently been proposed for characterizing canine PDA. In human patients arterial angiography is routinely performed percutaneously via the femoral artery, but in dogs the risk of bleeding is high using this technique5,13-15. To avoid this complication a surgical approach to the femoral or carotid artery16 is commonly performed with vessel repair or complete ligation following the intervention13,17. The aims of this study were (1) to assess the safety and utility of percutaneous angiography via the brachial artery and (2) to analyze PDA morphology and dimensions in dogs.
Materials and methods Forty-nine dogs referred to the Medical and Forensic Veterinary Clinic at the Justus-Liebig-University of Giessen with heart murmur and clinical and echocardiographical diagnosis of left to right PDA were included in the study (November 1995 to January 1999). Dogs with mitral valve dysplasia (n = 2), heart failure (NYHA grade 3 or 4, n = 24) and atrial fibrillation (n = 7) were included in the study population. Dogs with additional congenital heart defects, which could potentially influence PDA morphology (e.g. pulmonic stenosis) were excluded.
introduced through the needle to facilitate placement of a 3F or a 4F catheter introducer. In larger dogs a 5F or 6F introducer was subsequently exchanged for the smaller one (Figure 1). If the right brachial artery approach was not successful, an introducer was placed in the right femoral artery. Angiography was performed using 3F to 6F pigtail catheter positioned in the descending aorta in the region of the PDA. A venous approach was selected for all dogs weighing less than 3.0 kg. A 5F introducer was placed in the right femoral vein after detecting the vein with a Doppler deviceg. Using a 5F open-ended multipurpose catheter, a 0.038 inch straight guide wire was passed through the PDA into the descending aorta. Subsequently a 4F pigtail catheter was placed over the guide wire into the descending aorta. The position of the catheter was optimized using injections of small amounts of contrast media. Angiography was performed in lateral projection on 10 x 10 cm films at 6 frames/second. Contrast mediumh (1.0-1.2 ml/kg) was injected within 1 second into the descending aorta with an automatic injectori.
Figure 1 - Percutaneous approach to the brachial artery. A valved introducer was placed into the brachial artery just above the elbow joint.
Dogs of 21 different breeds were included in the study. The predominant breeds were German shepherd dog (n = 15), Polski Owczarek Nizinny (n = 4), Miniature Schnauzer (n = 4), mixed breed dog (n = 4) and Canadian shepherd dog (n = 3). There were 30 female and 19 male dogs. Body weight ranged from 1.5 to 50.0 kg (median 11.5, mean 15.73 ± 12.04); six (12%) had a body weight less than 3.0 kg. The dogs were between 2.6 and 65.5 (median 10.3, mean 14.30 ± 14.51) months old (Table 1). Twenty-two dogs had reached maturity, and only 7 (32%) of these dogs weighted less than 13.0 kg. If considered clinically necessary, dogs were treated with ß-methyldigoxina (0.005 mg/kg PO q12h); furosemideb (1.0-2.0 mg/kg PO q12h); and/or ramiprilc (0.125 mg/kg PO q24h) prior to catheterization and angiography. Procedure Anesthesia was induced using a combination of levomethadonhydrochlorid with fenpipramidhydrochloridd (0.5 mg/kg IV) and diazepame (0.5 mg/kg IV) and was maintained with isofluranef (1.7-2.0 %). All dogs were placed in right lateral recumbency with a radiodense scale between the table and patient. Right axillary and inguinal regions were surgically prepared. An approach to the brachial artery was attempted in all dogs weighing 3.0 kg or more (n = 43). After palpation of the brachial artery a small incision was made in the skin just above the elbow joint. A 20G needle with an internal diameter of 0.021 inch was used to puncture the brachial artery. A 0.020 inch guide wire was 22
PDA measurements One picture which best showed the PDA morphology was selected and scanned to handle in a personal computer. PDA morphology was classified to an adapted human scoring system11 without subclassification (Figure 2). Briefly, the following types exist; type A: narrowest segment at the pulmonary insertion, with a well-defined ampulla at the aortic end; type B: short and narrowed at the aortic insertion; type C: tubular, without constriction, type D: multiple constrictions; type E: elongated conical appearance with a constriction remote from the ventral border of the trachea.
Matthias Schneider; Ingo Schneider; Nicolai Hildebrandt; Martin Wehner classification scheme has been proposed by Krichenko and colleagues11. Adaptations of the human classification systems7 as well as a specifically designed veterinary classification system12 have recently been proposed for characterizing canine PDA. In human patients arterial angiography is routinely performed percutaneously via the femoral artery, but in dogs the risk of bleeding is high using this technique5,13-15. To avoid this complication a surgical approach to the femoral or carotid artery16 is commonly performed with vessel repair or complete ligation following the intervention13,17. The aims of this study were (1) to assess the safety and utility of percutaneous angiography via the brachial artery and (2) to analyze PDA morphology and dimensions in dogs.
Materials and methods Forty-nine dogs referred to the Medical and Forensic Veterinary Clinic at the Justus-Liebig-University of Giessen with heart murmur and clinical and echocardiographical diagnosis of left to right PDA were included in the study (November 1995 to January 1999). Dogs with mitral valve dysplasia (n = 2), heart failure (NYHA grade 3 or 4, n = 24) and atrial fibrillation (n = 7) were included in the study population. Dogs with additional congenital heart defects, which could potentially influence PDA morphology (e.g. pulmonic stenosis) were excluded.
introduced through the needle to facilitate placement of a 3F or a 4F catheter introducer. In larger dogs a 5F or 6F introducer was subsequently exchanged for the smaller one (Figure 1). If the right brachial artery approach was not successful, an introducer was placed in the right femoral artery. Angiography was performed using 3F to 6F pigtail catheter positioned in the descending aorta in the region of the PDA. A venous approach was selected for all dogs weighing less than 3.0 kg. A 5F introducer was placed in the right femoral vein after detecting the vein with a Doppler deviceg. Using a 5F open-ended multipurpose catheter, a 0.038 inch straight guide wire was passed through the PDA into the descending aorta. Subsequently a 4F pigtail catheter was placed over the guide wire into the descending aorta. The position of the catheter was optimized using injections of small amounts of contrast media. Angiography was performed in lateral projection on 10 x 10 cm films at 6 frames/second. Contrast mediumh (1.0-1.2 ml/kg) was injected within 1 second into the descending aorta with an automatic injectori.
Procedure Anesthesia was induced using a combination of levomethadonhydrochlorid with fenpipramidhydrochloridd (0.5 mg/kg IV) and diazepame (0.5 mg/kg IV) and was maintained with isofluranef (1.7-2.0 %). All dogs were placed in right lateral recumbency with a radiodense scale between the table and patient. Right axillary and inguinal regions were surgically prepared. An approach to the brachial artery was attempted in all dogs weighing 3.0 kg or more (n = 43). After palpation of the brachial artery a small incision was made in the skin just above the elbow joint. A 20G needle with an internal diameter of 0.021 inch was used to puncture the brachial artery. A 0.020 inch guide wire was 22
Figure 2 - Configuration of the ductus as seen in lateral angiography (see text, pictures in accordance with human classification11). AO = aorta, MPA = main pulmonary artery.
for 15 minutes while the puncture site of the artery was additionally compressed using a pressure bandage for approximately 12 hours. The patients stayed in the intensive care unit for 6-12 hours and were subsequently examined over 4-7 days for complications such as bleeding or neurological signs. Clavulanic-acid potentiated amoxicillinj (15.0-20.0 mg/kg IV or PO q12h) was administered to all dogs for 7 days starting on the day of intervention. Statistical analysis
Figure 3 - Drawing of the PDA and measurements. AO = aorta, PDA = patent ductus arteriosus, MPA = main pulmonary artery. (a) ductal minimal diameter, (b) ampulla diameter, (c) ampulla length, (d) angle between PDA and descending aorta.
Figure 1 - Percutaneous approach to the brachial artery. A valved introducer was placed into the brachial artery just above the elbow joint.
Data were tested for normal distribution (KolmogorowSmirnow test). Independently of these results the data are reported in Table 1 as mean ± standard deviation, median and range to be able to compare the data with most other studies. All statistical calculations and illustrations were performed using a statistical software packagek. The relationship between minimal diameter and body weight as well as age was tested using Pearson- respectively Spearmancorrelation and displayed as linear regression. The Student ttest was used to compare the difference of PDA measurements between different sexes (male, female), different body weight (< 13.0 kg, ≥ 13.0 kg) and between type E and type A ductus. A P-value of 0.05 or less was considered significant.
Results Procedure
Dogs of 21 different breeds were included in the study. The predominant breeds were German shepherd dog (n = 15), Polski Owczarek Nizinny (n = 4), Miniature Schnauzer (n = 4), mixed breed dog (n = 4) and Canadian shepherd dog (n = 3). There were 30 female and 19 male dogs. Body weight ranged from 1.5 to 50.0 kg (median 11.5, mean 15.73 ± 12.04); six (12%) had a body weight less than 3.0 kg. The dogs were between 2.6 and 65.5 (median 10.3, mean 14.30 ± 14.51) months old (Table 1). Twenty-two dogs had reached maturity, and only 7 (32%) of these dogs weighted less than 13.0 kg. If considered clinically necessary, dogs were treated with ß-methyldigoxina (0.005 mg/kg PO q12h); furosemideb (1.0-2.0 mg/kg PO q12h); and/or ramiprilc (0.125 mg/kg PO q24h) prior to catheterization and angiography.
Journal of Veterinary Cardiology, Vol.5, No. 2, November 2003
PDA measurements One picture which best showed the PDA morphology was selected and scanned to handle in a personal computer. PDA morphology was classified to an adapted human scoring system11 without subclassification (Figure 2). Briefly, the following types exist; type A: narrowest segment at the pulmonary insertion, with a well-defined ampulla at the aortic end; type B: short and narrowed at the aortic insertion; type C: tubular, without constriction, type D: multiple constrictions; type E: elongated conical appearance with a constriction remote from the ventral border of the trachea.
Figure 3 shows the PDA measurements: the diameter of the PDA at the connection to the main pulmonary artery = minimal diameter (a); the diameter of the PDA ampulla in the middle of the vessel (b); the ampulla length at the cranial border (c); and the angle between descending aorta and ductal ampulla. All measurements were done to the nearest 0.1 mm by magnification correction in comparison to the radiodense scale. In 8 dogs measurements were made using both the radiodense scale on the table and a radiographic marker catheter in the descending aorta, allowing for comparison of the two methods and calculation of the percent difference. To describe the PDA morphology more exactly, the ratios of ampulla diameter to minimal PDA diameter and ampulla length to ampulla diameter were calculated. Post angiography different coil-systems were used to close the PDA under the same anesthesia. In dogs with an arterial approach, angiography was repeated after successful embolization. At the end of catheter intervention, the puncture site of the femoral vein was compressed manually
In 41/43 dogs (95 %) weighing ≥ 3.0 kg the percutaneous right brachial arterial approach was successful using a 3F (n=4), 4F (n=17), 5F (n=17) or 6F (n=3) introducer. In two dogs placing the guide wire into the vessel proved impossible after puncturing the brachial artery. A small haematoma precluded further puncture of the brachial artery and a percutaneous right femoral artery approach was selected. Two dogs with severe congestive heart failure and atrial fibrillation died during catheter intervention, therefore only 39 patients could be evaluated for complications. Two dogs displayed radial nerve paralysis after the procedure but recovered normal neurologic function after 4 and 6 days without treatment. No dog experienced arterial hemorrhage. Percutaneous access to the femoral vein with antegrade catheterization of the PDA was achieved in all six dogs weighing less than 3.0 kg. No complications were experienced with the venous approach. PDA morphology and dimensions The PDA extended from the ventral margin of the descending aorta to the cranial border of the main pulmonary artery (MPA) near its bifurcation in all dogs. The mean angle between descending aorta and PDA was 148.8 ± 7.6 degree (range 117 – 164). All but one PDA had a wide ampulla at the aortic orifice and a constriction at the insertion to the MPA. The most frequently encountered PDA-type was E (elongated conical, n=39, 80%), followed by type A (conical, n=9, 18%). Only one dog (2%) had a type D (two constrictions) (see Figure 4). No dog had a tubular duct (type C) or a ductus with a constriction at the aortic site only (type B). 23
Matthias Schneider; Ingo Schneider; Nicolai Hildebrandt; Martin Wehner
C
Figure 4 - Examples of different catheter placement and PDA-types
A
A) The angiographic catheter is placed from the brachial artery (a), through the brachiocephalic trunk into the descending aorta. The PDA (b) has an elongated conical form with a well-defined constriction (c) at the insertion to the MPA (type E).
C) The angiographic catheter is placed from the brachial artery. The PDA has two constrictions one at the pulmonic (a) and one at the aortic (b) site (type D).
The minimal PDA diameter had a mean dimension of 3.79 ± 1.55 mm (range 1.5 to 6.9, median 3.4). In 20/49 dogs (41%) the minimal PDA diameter measured more than 4.0 mm. There was a significant correlation (Pearson, r = 0.6523, p < 0.0001) between body weight and minimal PDA diameter (see Figure 5).
B
PDA minimal diameter (mm)
Figure 5 - Linear association of PDA minimal diameter (mm) and body weight. The solid line represents the line of best fit, the inner dashed lines represents the 95% confidence intervals for the line of best fit and the outer dashed lines represents the 95% prediction interval for the observation.
B) The catheter is placed from the femoral vein through the right heart antegrade through the PDA into the descending aorta. The PDA (a) is short with a constriction (b) at the pulmonic site (type A).
Table 1 - Patients data and angiographic dimensions of the PDA in 49 dogs. parameter patients data: age (mo) body weight (kg) angiographic measurements: angle between aorta and PDA (degree) minimal diameter (mm) ampulla diameter (mm) ampulla length (mm) ratios: ampulla diameter to minimal diameter ampulla length to ampulla diameter
24
range
median
mean
SD
normal distribution
2.6 - 65.5 1.5 - 50.0
10.3 11.5
14.30 15.73
14.52 12.04
no yes
117 - 164 1.5 - 6.9 3.9 - 15.9 3.9 - 22.5
150 3.4 8.0 11.3
148.80 3.79 8.57 11.84
7.60 1.55 2.98 4.48
yes yes yes yes
1.6 - 4.1 0.5 - 2.6
2.3 1.4
2.37 1.43
0.45 0.45
yes yes
Matthias Schneider; Ingo Schneider; Nicolai Hildebrandt; Martin Wehner
Journal of Veterinary Cardiology, Vol.5, No. 2, November 2003 Twenty-six dogs with a body weight less than 13.0 kg had a mean PDA minimal diameter of 2.72 ± 0.74 mm (range 1.4 – 4.3) and one (4%) of these had a PDA minimal diameter more than 4.0 mm. In contrast 23 dogs weighing 13.0 kg or more had a mean PDA minimal diameter of 5.00 ± 1.31 mm (range 1.7 – 6.9) and 19 (83%) had a PDA minimal diameter more than 4.0 mm. The difference between the two groups was significant (p < 0.0001).
C
Figure 4 - Examples of different catheter placement and PDA-types
A
Correlation between minimal diameter and age was not significant (Spearman, p = 0.0710). There was no significant difference of PDA minimal diameter between male (n = 19) and female dogs (n = 30, p = 0.9918) nor between dogs with type A (n = 9) and type E ductus (n = 39, p = 0.2661).
A) The angiographic catheter is placed from the brachial artery (a), through the brachiocephalic trunk into the descending aorta. The PDA (b) has an elongated conical form with a well-defined constriction (c) at the insertion to the MPA (type E).
C) The angiographic catheter is placed from the brachial artery. The PDA has two constrictions one at the pulmonic (a) and one at the aortic (b) site (type D).
The minimal PDA diameter had a mean dimension of 3.79 ± 1.55 mm (range 1.5 to 6.9, median 3.4). In 20/49 dogs (41%) the minimal PDA diameter measured more than 4.0 mm. There was a significant correlation (Pearson, r = 0.6523, p < 0.0001) between body weight and minimal PDA diameter (see Figure 5).
B
PDA minimal diameter (mm)
Figure 5 - Linear association of PDA minimal diameter (mm) and body weight. The solid line represents the line of best fit, the inner dashed lines represents the 95% confidence intervals for the line of best fit and the outer dashed lines represents the 95% prediction interval for the observation.
B) The catheter is placed from the femoral vein through the right heart antegrade through the PDA into the descending aorta. The PDA (a) is short with a constriction (b) at the pulmonic site (type A).
Table 1 - Patients data and angiographic dimensions of the PDA in 49 dogs. parameter patients data: age (mo) body weight (kg) angiographic measurements: angle between aorta and PDA (degree) minimal diameter (mm) ampulla diameter (mm) ampulla length (mm) ratios: ampulla diameter to minimal diameter ampulla length to ampulla diameter
24
range
median
mean
SD
normal distribution
2.6 - 65.5 1.5 - 50.0
10.3 11.5
14.30 15.73
14.52 12.04
no yes
117 - 164 1.5 - 6.9 3.9 - 15.9 3.9 - 22.5
150 3.4 8.0 11.3
148.80 3.79 8.57 11.84
7.60 1.55 2.98 4.48
yes yes yes yes
1.6 - 4.1 0.5 - 2.6
2.3 1.4
2.37 1.43
0.45 0.45
yes yes
Mean diameter of the PDA ampulla was 8.57 ± 2.98 mm (range 3.8 - 15.9). Ratio of PDA ampulla diameter to PDA minimal diameter was 1.6 up to 4.1 (2.37 ± 0.45) and was not significantly (p = 0.7209) different between type E and type A ductus. In 39/49 (80%) dogs the ampulla was at least was two times bigger than the minimal diameter. Only two dogs had a ratio less than 1.8. The mean length of ampulla was 11.84 ± 4.48 mm (range 3.9 and 22.5). Ratio between ampulla length and diameter ranged between 0.5 - 2.6 (1.43 ± 0.45). 43/49 (88%) dogs had a ratio of 1.0 or more. The measurement with the radiographic scale on the table underestimated the measurement with marker catheter by 5%, 6%, 6%, 7% in 4 large dogs (≥ 13.0 kg) and by 2%, 2%, 3%, 3% in 4 small (< 13.0 kg) dogs.
Discussion This study shows that percutaneous approach to the brachial artery is possible in most dogs weighing more than 3.0 kg body weight and that the procedure has a minimal risk of haemorrhage. The high success (95%) of percutaneous brachial arterial catheterization may have been facilitated by the hyperkinetic pulse in dogs with a PDA, and should be studied in dogs with other indications for left heart catheterization. No bleeding appeared in 39 cases of brachial artery puncture in contrast to substantially higher rates when the femoral artery was used5,13,14. The proximity of the brachial artery to the humerus with only a small amount of interposed soft tissue permits effective compression of the vessel when bandaged. Secondly, the bandage could be fastened around the shoulder to avoid distal displacement. Two large dogs showed a disturbance of the radial nerve after the puncture of brachial artery. The probable cause may be a injury of the nerve during arterial puncture, compression of the nerve by the introducer or by a bandage fastened too tightly. Catheterization via the brachial artery has a second advantage in comparison to the femoral artery given the shorter distance and improved catheter angle18 in that it is relatively easy to catheterise the left ventricle. Additionally, by using a shorter catheter, it is possible to reduce the catheter diameter without reduction of maximal flow rate. Disadvantages of brachial artery catheterization include the small vessel diameter and limited ability to access a patent ductus arteriosus for transcatheter occlusion.
For small dogs (< 3.0 kg) it is possible, to dispense with an arterial approach and obtain access via the femoral vein. There are however some disadvantages of this procedure. In very small dogs it can be difficult to place the catheter from the femoral vein through the right heart and to arrive at the PDA antegrade from the main pulmonary artery (MPA). Moreover, it is not possible to accomplish an arterial angiography after attempted PDA occlusion. In all six small dogs studied here there it was no problem advancing the catheter antegrade into the ductus, and because the PDA were small, control angiography was not necessary. While not performed in this study, one could inject contrast medium into the MPA and evaluate ductal patency during the levo phase of the angiogram before and after an coil embolization. Alternatively, angiography could be replaced by color-Doppler echocardiographic examination after the embolization procedure19. The angle between descending aorta and PDA (range 117 – 164 degree) was larger than in a human study (range 80 – 139 degree)20. By this angle it is nearly impossible to advance a catheter from the brachial or carotid artery through the PDA into the MPA, therefore PDA occlusion using approach from this artery is not possible. The forms of PDA, we observed were similar to those reported in human studies and other studies in dogs, but the distribution of the types is different. In humans type A (65%) is frequent and type E (6%) is rare11. Similar distributions could be found in the most human studies, but there seem to be regional differences also, because in a study from southern Europe the type E (39%) was more frequent than type A (33%)21. We found the type E in 80% and type A in 18% of the dogs. The elongated conical form (type E) was also the most frequent type in the USA (43% called as type IIa12). The frequency of tubular ductus (without a constriction, type C) is of special importance, because it is very difficult to embolize such a ductus. In human medicine the number is low (8%)11 and we did not observe any PDA with this morphology. Miller and colleagues12 found the tubular ductus type in dogs, but did not told the exact number. Stokhof and colleagues7 also described PDA morphology in dogs but not according with the classification scheme of Krichenko and colleagues11. The authors described a “tubular duct” in 7/15 dogs, but they classified the PDA as “type E” in 6 of them (elongated conical according Krichenko and colleagues11). In some human studies the type E ducts is incorrectly referred to as “tubular, with pulmonary constriction”22. One reason why we did not found any tubular ductus might be our selection of PDA with left to right shunt, because many of the tubular PDA develop a right to left shunt during the first months of the life23,24. In prior studies, there was no significant correlation between the minimal ductal diameter and patient body weight or age either in humans11 or in dogs12. We found a significant correlation between PDA minimal diameter and body weight, but not to age. A possible reason is, that none of our dogs had a tubular duct, which have a significant larger diameter than other PDA types12. Additionally a higher number of large dogs improves the likelihood of demonstrating a correlation between PDA minimal diameter 25
Matthias Schneider; Ingo Schneider; Nicolai Hildebrandt; Martin Wehner and body weight. In this study the body weight (15.73 ± 12.04 kg, median 11.5 kg) was high compared to American studies (7.6 ± 5.8 kg12, median 7.5 kg25), and only 32% of the dogs which had reached maturity had a body weight less than < 13.0 kg, compared to 85% in a large American study26. These differences can be explained by the high percentage of large breed dogs, like German Shepherd (31%) in our study. In an English study15 with 20% German Shepherds the median body weight (12.5 kg) was higher than in the American studies and only minimal lower than in this study. The mean PDA minimal diameter in our study was 3.79 ± 1.55 which is similar to another study in dogs (3.8 ± 2.2)12 but larger than in humans (3.2 ± 1.0)11. A PDA larger than 4.0 mm is observed in only 20% of the human patients11 but in 41% of the dogs in this study. Such large PDA are difficult to occlude by means of coil techniques and these dogs often require some other occlusion system. Given the relation between body weight and PDA minimal diameter and the high number of small breed dogs (85% less than 13.0 kg at maturity)26 in the USA, the percentage of dogs with a PDA more than 4.0 mm might be much lower in the USA than in our study. In a human study27 it was found that the PDA is not a fixed structure. It could be stretched to twice the size of angiographic minimal diameter by a soft latex balloon. This may be one reason why Lloyd and colleagues28 proposed using a coil loop diameter two times bigger than the PDA minimal diameter. In our dogs the ratio between PDA ampulla and minimal diameter was near or about two and all PDA had a constriction at pulmonic site suggesting that it is possible to place a occlusion system with spherical form and a diameter two times the PDA minimal diameter. Because in most dogs the PDA ampulla length is larger than the diameter, a spherical occlusion device should not project into the descending aorta. There are several available methods to correct the magnification of a fluoroscopy machine. The most exact way is to use a marker at the level of the vessel29. The best method is to use a special angiographic catheter with two ore more radiographic markers, normally 1 or 2 cm apart. Many human studies simply use the diameter of the angiographic catheter as reference30-32, but it is not easy to measure the catheter diameter exactly and a 0.1 mm error using a 5F (1.66 mm) or 4F (1.33 mm) catheter leads to 6% or 8% failure in all dimensions. Other authors use a scale on the table7 or on the chest33. If the radiographic scale is not on the same level as the vessel (like PDA), it is a potential source for failure in measurements. In our study the scale was on the table and the films are recorded above the dog, leading to underestimation of the true dimensions. However it could be shown by comparison to a radiographic marker catheter, that this error is low in small dogs (2-3%) and in larger dogs also (5-7%).
Study limitation We used only lateral projections for measuring the PDA dimensions. This procedure is also done in the most human11 and veterinary7,12 studies because in the dorso-ventral projection the aorta overlaps the PDA, making it impossible 26
to judge the PDA morphology and to measure the PDA dimensions. Measurement in a single plane may cause slight underestimation of the correct value of PDA minimal diameter4,7 and this has to be taken in account when performing a PDA embolization. a Lanitop, Boeringer Mannheim, Mannheim, Germany b Lasix, Hoechst, Frankfurt, Germany c Delix, Hoechst, Frankfurt, Germany d Polamivet, Hoechst Roussel Vet, Unterschleissheim, Germany e Valium, Hoffmann-La Roche AG, Grenzach-Wyhlen, Germany f Forene, Abbot GmbH, Wiesbaden, Germany g Ultrasonic Doppler Flow Detector Model 811, Parks electronics, Aloha, Ore h Conray 70, Mallinckrodt Hennef, Hennef Sieg, Germany i Angiomat 3000, Angiomed GmbH, Karlsruhe, Germany j Augmentan SmithKline Beecham, Bönen, Germany or Synulox, Pfizer GmbH, Karlsruhe, Germany k GraphPad Prism 3.0, GrapPad Software, Inc, San Diego, USA
References 1. Snaps FR, McEntee K, Saunders JH, Dondelinger RF. Treatment of patent ductus arteriosus by placement of intravascular coils in a pup. J Am Vet Med Assoc 1995; 207: 724-725. 2. Grifka RG, Miller MW, Frischmeyer KJ, Mullins CE. Transcatheter occlusion of a patent ductus arteriosus in a Newfoundland puppy using the Gianturco-Grifka vascular occlusion device. J Vet Intern Med 1996; 10: 42-44. 3. Fellows CG, Lerche P, King G, Tometzki A. Treatment of patent ductus arteriosus by placement of two intravascular embolisation coils in a puppy. J Small Anim Pract 1998; 39: 196-199. 4. Fox PR, Bond BR, Sommer RJ. Nonsurgical transcatheter coil occlusion of patent ductus arteriosus in two dogs using a preformed nitinol snare delivery technique. J Vet Intern Med 1998; 12: 182-185. 5. Glaus TM, Gardelle O, Bass M, Kiowski WK. Verschluss eines persistierenden ductus arteriosus botalli bei zwei hunden mittels transarterieller coil-embolisation. Schweiz Arch Tierheilk 1999; 141: 191-194. 6. Saunders JH, Snaps FR, Peeters D, et al. Use of a balloon occlusion catheter to facilitate transarterial coil embolisation of a patent ductus arteriosus in two dogs. Vet Rec 1999; 145: 544-546. 7. Stokhof AA, Sreeram N, Wolvekamp WT. Transcatheter closure of patent ductus arteriosus using occluding spring coils. J Vet Intern Med 2000; 14: 452-455. 8. Schneider M, Hildebrandt N, Schweigl T, et al. Transvenous embolization of small patent ductus arteriosus with single detachable coils in dogs. J Vet Intern Med 2001; 15: 222-228. 9. Buchanan JW, Patterson DF. Selective angiography and angiocardiography in dogs with congenital cardiovascular disease. J Am Vet Rad Soc 1965; 6: 21-39. 10. Bonagura JD, Darke PGG. Congenital heart disease. In Ettinger SJ, Feldman EC ed. Textbook of Veterinary Internal Medicine. Philadelphia, WB Saunders; 1994: 892-943. 11. Krichenko A, Benson LN, Burrows P, et al. Angiographic classification of the isolated, persistently patent ductus arteriosus and implications for percutaneous catheter occlusion. Am J Cardiol 1989; 63: 877-880. 12. Miller MW, Meurs KM, Lehmkuhl LB, et al. Angiographic classification of patent ductus arteriosus in the dog.
Matthias Schneider; Ingo Schneider; Nicolai Hildebrandt; Martin Wehner and body weight. In this study the body weight (15.73 ± 12.04 kg, median 11.5 kg) was high compared to American studies (7.6 ± 5.8 kg12, median 7.5 kg25), and only 32% of the dogs which had reached maturity had a body weight less than < 13.0 kg, compared to 85% in a large American study26. These differences can be explained by the high percentage of large breed dogs, like German Shepherd (31%) in our study. In an English study15 with 20% German Shepherds the median body weight (12.5 kg) was higher than in the American studies and only minimal lower than in this study. The mean PDA minimal diameter in our study was 3.79 ± 1.55 which is similar to another study in dogs (3.8 ± 2.2)12 but larger than in humans (3.2 ± 1.0)11. A PDA larger than 4.0 mm is observed in only 20% of the human patients11 but in 41% of the dogs in this study. Such large PDA are difficult to occlude by means of coil techniques and these dogs often require some other occlusion system. Given the relation between body weight and PDA minimal diameter and the high number of small breed dogs (85% less than 13.0 kg at maturity)26 in the USA, the percentage of dogs with a PDA more than 4.0 mm might be much lower in the USA than in our study. In a human study27 it was found that the PDA is not a fixed structure. It could be stretched to twice the size of angiographic minimal diameter by a soft latex balloon. This may be one reason why Lloyd and colleagues28 proposed using a coil loop diameter two times bigger than the PDA minimal diameter. In our dogs the ratio between PDA ampulla and minimal diameter was near or about two and all PDA had a constriction at pulmonic site suggesting that it is possible to place a occlusion system with spherical form and a diameter two times the PDA minimal diameter. Because in most dogs the PDA ampulla length is larger than the diameter, a spherical occlusion device should not project into the descending aorta. There are several available methods to correct the magnification of a fluoroscopy machine. The most exact way is to use a marker at the level of the vessel29. The best method is to use a special angiographic catheter with two ore more radiographic markers, normally 1 or 2 cm apart. Many human studies simply use the diameter of the angiographic catheter as reference30-32, but it is not easy to measure the catheter diameter exactly and a 0.1 mm error using a 5F (1.66 mm) or 4F (1.33 mm) catheter leads to 6% or 8% failure in all dimensions. Other authors use a scale on the table7 or on the chest33. If the radiographic scale is not on the same level as the vessel (like PDA), it is a potential source for failure in measurements. In our study the scale was on the table and the films are recorded above the dog, leading to underestimation of the true dimensions. However it could be shown by comparison to a radiographic marker catheter, that this error is low in small dogs (2-3%) and in larger dogs also (5-7%).
Study limitation We used only lateral projections for measuring the PDA dimensions. This procedure is also done in the most human11 and veterinary7,12 studies because in the dorso-ventral projection the aorta overlaps the PDA, making it impossible 26
to judge the PDA morphology and to measure the PDA dimensions. Measurement in a single plane may cause slight underestimation of the correct value of PDA minimal diameter4,7 and this has to be taken in account when performing a PDA embolization. a Lanitop, Boeringer Mannheim, Mannheim, Germany b Lasix, Hoechst, Frankfurt, Germany c Delix, Hoechst, Frankfurt, Germany d Polamivet, Hoechst Roussel Vet, Unterschleissheim, Germany e Valium, Hoffmann-La Roche AG, Grenzach-Wyhlen, Germany f Forene, Abbot GmbH, Wiesbaden, Germany g Ultrasonic Doppler Flow Detector Model 811, Parks electronics, Aloha, Ore h Conray 70, Mallinckrodt Hennef, Hennef Sieg, Germany i Angiomat 3000, Angiomed GmbH, Karlsruhe, Germany j Augmentan SmithKline Beecham, Bönen, Germany or Synulox, Pfizer GmbH, Karlsruhe, Germany k GraphPad Prism 3.0, GrapPad Software, Inc, San Diego, USA
References 1. Snaps FR, McEntee K, Saunders JH, Dondelinger RF. Treatment of patent ductus arteriosus by placement of intravascular coils in a pup. J Am Vet Med Assoc 1995; 207: 724-725. 2. Grifka RG, Miller MW, Frischmeyer KJ, Mullins CE. Transcatheter occlusion of a patent ductus arteriosus in a Newfoundland puppy using the Gianturco-Grifka vascular occlusion device. J Vet Intern Med 1996; 10: 42-44. 3. Fellows CG, Lerche P, King G, Tometzki A. Treatment of patent ductus arteriosus by placement of two intravascular embolisation coils in a puppy. J Small Anim Pract 1998; 39: 196-199. 4. Fox PR, Bond BR, Sommer RJ. Nonsurgical transcatheter coil occlusion of patent ductus arteriosus in two dogs using a preformed nitinol snare delivery technique. J Vet Intern Med 1998; 12: 182-185. 5. Glaus TM, Gardelle O, Bass M, Kiowski WK. Verschluss eines persistierenden ductus arteriosus botalli bei zwei hunden mittels transarterieller coil-embolisation. Schweiz Arch Tierheilk 1999; 141: 191-194. 6. Saunders JH, Snaps FR, Peeters D, et al. Use of a balloon occlusion catheter to facilitate transarterial coil embolisation of a patent ductus arteriosus in two dogs. Vet Rec 1999; 145: 544-546. 7. Stokhof AA, Sreeram N, Wolvekamp WT. Transcatheter closure of patent ductus arteriosus using occluding spring coils. J Vet Intern Med 2000; 14: 452-455. 8. Schneider M, Hildebrandt N, Schweigl T, et al. Transvenous embolization of small patent ductus arteriosus with single detachable coils in dogs. J Vet Intern Med 2001; 15: 222-228. 9. Buchanan JW, Patterson DF. Selective angiography and angiocardiography in dogs with congenital cardiovascular disease. J Am Vet Rad Soc 1965; 6: 21-39. 10. Bonagura JD, Darke PGG. Congenital heart disease. In Ettinger SJ, Feldman EC ed. Textbook of Veterinary Internal Medicine. Philadelphia, WB Saunders; 1994: 892-943. 11. Krichenko A, Benson LN, Burrows P, et al. Angiographic classification of the isolated, persistently patent ductus arteriosus and implications for percutaneous catheter occlusion. Am J Cardiol 1989; 63: 877-880. 12. Miller MW, Meurs KM, Lehmkuhl LB, et al. Angiographic classification of patent ductus arteriosus in the dog.
Journal of Veterinary Cardiology, Vol.5, No. 2, November 2003 23. Patterson DF, Pyle RL, Buchanan JW, et al. Hereditary patent ductus arteriosus and its sequelae in the dog. Circ Res 1971; 29: 1-13. 24. Pyle RL, Park RD, Alexander AF, Hill BL. Patent ductus arteriousus with pulmonary hypertension in the dog. J Am Vet Med Assoc 1981; 178: 565-571. 25. Birchard SJ, Bonagura JD, Fingland RB. Results of ligation of patent ductus arteriosus in dogs: 201 cases (1969-1988). J Am Vet Med Assoc 1990; 196: 2011-2013. 26. Eyster GE, Eyster JT, Cords GB, Johnston J. Patent ductus arteriosus in the dog: characteristics of occurence and results of surgery in one hundred consecutive cases. J Am Vet Med Assoc 1976; 168: 435-438. 27. Tomita H, Fuse S, Chiba S. Stretched minimal diameter of the ductus and coil occlusion. Acta Paediatr Jpn 1998; 40: 453-456. 28. Lloyd TR, Fedderly R, Mendelsohn AM, et al. Transcatheter occlusion of patent ductus arteriosus with Gianturco coils. Circulation 1993; 88: 1412-1420. 29. Sharafuddin MJA, Gu X, Titus JL, et al. Experimental evaluation of a new self-expanding patent ductus arteriosus occluder in a canine model. J Vasc Interv Radiol 1996; 7: 877-887. 30. Sahn DJ, Allen HD. Real-time cross-sectional echocardiographic imaging and measurement of the patent ductus arteriosus in infants and children. Circulation 1978; 58: 343-354. 31. Dalvi B, Goyal V, Narula D, et al. New technique using temporary balloon occlusion for transcatheter closure of patent ductus arteriosus with Gianturco coils. Cathet Cardiovasc Diagn 1997; 41: 62-70. 32. Wong JA, Shim D, Khoury PR, Meyer RA. Validation of color Doppler measurements of minimum patent ductus arteriosus diameters: significance for coil embolization. Am Heart J 1998; 136: 714-717. 33. Hijazi ZM. New closure devices for left-to-right shunt. Indian Heart J 1996; 48: 119-123.
Proceedings of the 16th ACVIM forum 1998: 244. 13. Kienle RD. Cardiac Catheterization. In Kittleson MD, Kienle RD ed. Small Animal Cardiovascular Medicine. St. Louis, Mosby, Inc; 1998: 118-132. 14. Miller MW, Meurs KM, Gordon SG, Spangler EA. Transarterial ductal occlusion using Gianturco vascular occlusion coils: 43 cases 1994-1998. J Vet Intern Med 1999; 13: 247. 15. Van Israel N, French AT, Dukes-McEwan J, Corcoran BM. Review of left-to-right shunting patent ductus arteriosus and short term outcome in 98 dogs. J Small Anim Pract 2002; 395-400. 16. Thomas WP, Sisson D. Cardiac catheterization and angiocardiography. In Fox PR, Sisson D, Moise NS ed. Textbook of Canine and Feline Cardiology: Principles and Clinical Practice. Philadelphia, WB Saunders; 1999: 173192. 17. Gerlach K, Skrodzki M, Trautvetter E. Kongenitale anomalien des aortenbogens beim Hund (I). Kleintierpraxis 1988; 33: 355-363. 18. Bonagura JD, Lehmkuhl LB. Congenital heart disease. In Fox PR, Sisson D, Moise NS ed. Canine and Feline Cardiology. Philadelphia, WB Saunders Company; 1999: 471-535. 19. Uzun O, Hancock S, Parsons JM, et al. Transcatheter occlusion of the arterial duct with Cook detachable coils: early experience. Heart 1996; 76: 269-273. 20. Abrams SE, Walsh KP. Arterial duct morphology with reference to angioplasty and stenting. Int J Cardiol 1993; 40: 27-33. 21. Bermudez CR, Velasco BJ, Herraiz JI, et al. Therapeutic catheterization: the percutaneous closure of a persistent ductus arteriosus and of interatrial communication. Rev Esp Cardiol 1992; 45: 42-50. 22. Belau L, Grävinghoff L, Keck EW. Verschluß des persistierenden ductus arteriousus Botalli ohne thorakotomie. Dtsch Med Wochenschr 1993; 118: 169-175.
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Journal of Veterinary Cardiology Official Journal of the European Society of Veterinary Cardiology Visit us at http://www/esvc.net/ Please notice that the editorial office is now in Paris: Pr Valérie Chetboul, Editorial Office, Journal of Veterinary Cardiology Unité de Cardiologie d'Alfort - UP de Médecine, ENVA 7 av. du Gal de gaulle - 94704 Maisons-Alfort cédex - France
Next meetings: ESVC/ECVIM-CA (info at: http://www.ecvim-ca.org/)
14th ECVIM-CA congress 2004 Congress Information: Barcelona, Spain. September 9-11 The congress will take place at the Autonomous University of Barcelona which is situated 25 minutes from the center of Barcelona.
ESVC precongress Pre-congress day, September 8, 2004 For informations, please contact Maria Fernandez del Palacio: [email protected] Hospital Clínico Veterinario, Universidad de Murcia, Facultad de Veterinaria 30100- Espinardo. Murcia. Spain - Phone. 34 968 364723
27
A new generation ACE inhibitor
Percutaneous angiography of Patent Ductus Arteriosus in dogs: techniques, results and implications for intravascular occlusion
Intervet has been at the forefront of veterinary cardiovascular medicine since 1994, when it launched the first ACE inhibitor for veterinary use.
Matthias Schneider1; Ingo Schneider2; Nicolai Hildebrandt3; Martin Wehner4
This revolutionised the treatment of congestive heart failure in dogs. Intervet is now able to present Vasotop, containing
Abstract
ramipril, the new generation ACE inhibitor, that
Objectives: To evaluate the percutaneous angiography and the morphology of patent ductus arteriosus (PDA) in dogs.
revolutionised human ACE inhibitor therapy. Vasotop: the next step forward for
Background: In contrast to surgical ligation the knowledge of angiographic morphology is necessary for intravascular PDA occlusion.
the treatment of congestive heart failure in dogs.
Young at Heart!
Methods: Forty-nine dogs with a left to right shunting PDA were included in a three-year, prospective study. In 43 dogs with a body weight ≥ 3.0 kg a percutaneous approach to brachial artery was tested. In six miniature dogs (< 3.0 kg) placement of angiographic catheter from femoral vein antegrade through the PDA was studied. Angiographic morphology and dimensions of PDA were analyzed. Results: Percutaneous approach to brachial artery was performed successfully in 41/43 (95%) dogs, in the remaining 2 dogs this approach was not possible and the femoral artery had to be used. Two dogs did not survive the procedure. Arterial bleeding was not a problem in any of the 39 cases in which percutaneous brachial artery catheterization was performed. Two dogs developed transient radial nerve paralysis that resolved 4 to 6 days later. The transvenous technique was successful in all 6 small dogs. In 39 dogs there was an elongated conical duct (type E). A conical duct (type A) was found in nine dogs and one dog had a PDA with two
constrictions (type D). The mean PDA minimal diameter was 3.78 ± 1.55 mm (range 1.5 to 6.9), in 20/49 dogs (41%) the minimal PDA diameter measured more than 4.0 mm. Conclusions: Percutaneous catheterization of the brachial artery using a vascular introducer is feasible and entails minimal risk of hemorrhage. Angiographic evaluation of the ductus arteriosus is easily performed with this technique, but coilimplantation is not possible by this approach. The frequency of PDA-types is different in dogs and humans and the PDA minimal diameter is larger in dogs.
Key words: Dog, patent ductus arteriosus, angiography, catheter, embolization
Patent ductus arteriosus (PDA) is one of the most common congenital heart diseases in dogs. It is treated commonly by surgical ligation or by intravascular occlusion using catheter techniques1-8. Angiography is not routinely performed in dogs undergoing PDA ligation9,10. Consequently, angiographic descriptions of canine PDAs are limited7,9. Knowledge of ductal morphology and dimensions is essential for successful intravascular occlusion. Measures of the minimal PDA diameter are used in human medicine to select the correctly sized embolization system. An angiographic PDA-type
DVM, Dr Med Vet, PD. DVM, Dr Med Vet. 3 DVM. 4 DVM. From the Medical and Forensic Veterinary Clinic, Department of Small Animal Internal Medicine, Justus-Liebig-University of Giessen, Giessen, Germany Short title: Angiography of Patent ductus arteriosus in dogs 1
060844
2
This study was performed at the Medical and Forensic Veterinary Clinic, Department of Small Animal Internal Medicine, Justus-Liebig-University of Giessen, Giessen, Germany Corresponding author: Matthias Schneider, Dr.med.vet., Medizinische und Gerichtliche Veterinärklink I, Innere Krankheiten der Kleintiere, Justus-LiebigUniversity Giessen, Frankfurterstr. 126, D-35392 Giessen, Germany; e-mail: [email protected]
Intervet International bv • P.O. Box 31 • 5830 AA Boxmeer • The Netherlands Phone: +31 485 587600 • Fax: +31 485 577333 • E-mail: [email protected] • www.intervet.com
21
Matthias Schneider; Ingo Schneider; Nicolai Hildebrandt; Martin Wehner classification scheme has been proposed by Krichenko and colleagues11. Adaptations of the human classification systems7 as well as a specifically designed veterinary classification system12 have recently been proposed for characterizing canine PDA. In human patients arterial angiography is routinely performed percutaneously via the femoral artery, but in dogs the risk of bleeding is high using this technique5,13-15. To avoid this complication a surgical approach to the femoral or carotid artery16 is commonly performed with vessel repair or complete ligation following the intervention13,17. The aims of this study were (1) to assess the safety and utility of percutaneous angiography via the brachial artery and (2) to analyze PDA morphology and dimensions in dogs.
Materials and methods Forty-nine dogs referred to the Medical and Forensic Veterinary Clinic at the Justus-Liebig-University of Giessen with heart murmur and clinical and echocardiographical diagnosis of left to right PDA were included in the study (November 1995 to January 1999). Dogs with mitral valve dysplasia (n = 2), heart failure (NYHA grade 3 or 4, n = 24) and atrial fibrillation (n = 7) were included in the study population. Dogs with additional congenital heart defects, which could potentially influence PDA morphology (e.g. pulmonic stenosis) were excluded.
introduced through the needle to facilitate placement of a 3F or a 4F catheter introducer. In larger dogs a 5F or 6F introducer was subsequently exchanged for the smaller one (Figure 1). If the right brachial artery approach was not successful, an introducer was placed in the right femoral artery. Angiography was performed using 3F to 6F pigtail catheter positioned in the descending aorta in the region of the PDA. A venous approach was selected for all dogs weighing less than 3.0 kg. A 5F introducer was placed in the right femoral vein after detecting the vein with a Doppler deviceg. Using a 5F open-ended multipurpose catheter, a 0.038 inch straight guide wire was passed through the PDA into the descending aorta. Subsequently a 4F pigtail catheter was placed over the guide wire into the descending aorta. The position of the catheter was optimized using injections of small amounts of contrast media. Angiography was performed in lateral projection on 10 x 10 cm films at 6 frames/second. Contrast mediumh (1.0-1.2 ml/kg) was injected within 1 second into the descending aorta with an automatic injectori.
Figure 1 - Percutaneous approach to the brachial artery. A valved introducer was placed into the brachial artery just above the elbow joint.
Dogs of 21 different breeds were included in the study. The predominant breeds were German shepherd dog (n = 15), Polski Owczarek Nizinny (n = 4), Miniature Schnauzer (n = 4), mixed breed dog (n = 4) and Canadian shepherd dog (n = 3). There were 30 female and 19 male dogs. Body weight ranged from 1.5 to 50.0 kg (median 11.5, mean 15.73 ± 12.04); six (12%) had a body weight less than 3.0 kg. The dogs were between 2.6 and 65.5 (median 10.3, mean 14.30 ± 14.51) months old (Table 1). Twenty-two dogs had reached maturity, and only 7 (32%) of these dogs weighted less than 13.0 kg. If considered clinically necessary, dogs were treated with ß-methyldigoxina (0.005 mg/kg PO q12h); furosemideb (1.0-2.0 mg/kg PO q12h); and/or ramiprilc (0.125 mg/kg PO q24h) prior to catheterization and angiography. Procedure Anesthesia was induced using a combination of levomethadonhydrochlorid with fenpipramidhydrochloridd (0.5 mg/kg IV) and diazepame (0.5 mg/kg IV) and was maintained with isofluranef (1.7-2.0 %). All dogs were placed in right lateral recumbency with a radiodense scale between the table and patient. Right axillary and inguinal regions were surgically prepared. An approach to the brachial artery was attempted in all dogs weighing 3.0 kg or more (n = 43). After palpation of the brachial artery a small incision was made in the skin just above the elbow joint. A 20G needle with an internal diameter of 0.021 inch was used to puncture the brachial artery. A 0.020 inch guide wire was 22
PDA measurements One picture which best showed the PDA morphology was selected and scanned to handle in a personal computer. PDA morphology was classified to an adapted human scoring system11 without subclassification (Figure 2). Briefly, the following types exist; type A: narrowest segment at the pulmonary insertion, with a well-defined ampulla at the aortic end; type B: short and narrowed at the aortic insertion; type C: tubular, without constriction, type D: multiple constrictions; type E: elongated conical appearance with a constriction remote from the ventral border of the trachea.
Matthias Schneider; Ingo Schneider; Nicolai Hildebrandt; Martin Wehner classification scheme has been proposed by Krichenko and colleagues11. Adaptations of the human classification systems7 as well as a specifically designed veterinary classification system12 have recently been proposed for characterizing canine PDA. In human patients arterial angiography is routinely performed percutaneously via the femoral artery, but in dogs the risk of bleeding is high using this technique5,13-15. To avoid this complication a surgical approach to the femoral or carotid artery16 is commonly performed with vessel repair or complete ligation following the intervention13,17. The aims of this study were (1) to assess the safety and utility of percutaneous angiography via the brachial artery and (2) to analyze PDA morphology and dimensions in dogs.
Materials and methods Forty-nine dogs referred to the Medical and Forensic Veterinary Clinic at the Justus-Liebig-University of Giessen with heart murmur and clinical and echocardiographical diagnosis of left to right PDA were included in the study (November 1995 to January 1999). Dogs with mitral valve dysplasia (n = 2), heart failure (NYHA grade 3 or 4, n = 24) and atrial fibrillation (n = 7) were included in the study population. Dogs with additional congenital heart defects, which could potentially influence PDA morphology (e.g. pulmonic stenosis) were excluded.
introduced through the needle to facilitate placement of a 3F or a 4F catheter introducer. In larger dogs a 5F or 6F introducer was subsequently exchanged for the smaller one (Figure 1). If the right brachial artery approach was not successful, an introducer was placed in the right femoral artery. Angiography was performed using 3F to 6F pigtail catheter positioned in the descending aorta in the region of the PDA. A venous approach was selected for all dogs weighing less than 3.0 kg. A 5F introducer was placed in the right femoral vein after detecting the vein with a Doppler deviceg. Using a 5F open-ended multipurpose catheter, a 0.038 inch straight guide wire was passed through the PDA into the descending aorta. Subsequently a 4F pigtail catheter was placed over the guide wire into the descending aorta. The position of the catheter was optimized using injections of small amounts of contrast media. Angiography was performed in lateral projection on 10 x 10 cm films at 6 frames/second. Contrast mediumh (1.0-1.2 ml/kg) was injected within 1 second into the descending aorta with an automatic injectori.
Procedure Anesthesia was induced using a combination of levomethadonhydrochlorid with fenpipramidhydrochloridd (0.5 mg/kg IV) and diazepame (0.5 mg/kg IV) and was maintained with isofluranef (1.7-2.0 %). All dogs were placed in right lateral recumbency with a radiodense scale between the table and patient. Right axillary and inguinal regions were surgically prepared. An approach to the brachial artery was attempted in all dogs weighing 3.0 kg or more (n = 43). After palpation of the brachial artery a small incision was made in the skin just above the elbow joint. A 20G needle with an internal diameter of 0.021 inch was used to puncture the brachial artery. A 0.020 inch guide wire was 22
Figure 2 - Configuration of the ductus as seen in lateral angiography (see text, pictures in accordance with human classification11). AO = aorta, MPA = main pulmonary artery.
for 15 minutes while the puncture site of the artery was additionally compressed using a pressure bandage for approximately 12 hours. The patients stayed in the intensive care unit for 6-12 hours and were subsequently examined over 4-7 days for complications such as bleeding or neurological signs. Clavulanic-acid potentiated amoxicillinj (15.0-20.0 mg/kg IV or PO q12h) was administered to all dogs for 7 days starting on the day of intervention. Statistical analysis
Figure 3 - Drawing of the PDA and measurements. AO = aorta, PDA = patent ductus arteriosus, MPA = main pulmonary artery. (a) ductal minimal diameter, (b) ampulla diameter, (c) ampulla length, (d) angle between PDA and descending aorta.
Figure 1 - Percutaneous approach to the brachial artery. A valved introducer was placed into the brachial artery just above the elbow joint.
Data were tested for normal distribution (KolmogorowSmirnow test). Independently of these results the data are reported in Table 1 as mean ± standard deviation, median and range to be able to compare the data with most other studies. All statistical calculations and illustrations were performed using a statistical software packagek. The relationship between minimal diameter and body weight as well as age was tested using Pearson- respectively Spearmancorrelation and displayed as linear regression. The Student ttest was used to compare the difference of PDA measurements between different sexes (male, female), different body weight (< 13.0 kg, ≥ 13.0 kg) and between type E and type A ductus. A P-value of 0.05 or less was considered significant.
Results Procedure
Dogs of 21 different breeds were included in the study. The predominant breeds were German shepherd dog (n = 15), Polski Owczarek Nizinny (n = 4), Miniature Schnauzer (n = 4), mixed breed dog (n = 4) and Canadian shepherd dog (n = 3). There were 30 female and 19 male dogs. Body weight ranged from 1.5 to 50.0 kg (median 11.5, mean 15.73 ± 12.04); six (12%) had a body weight less than 3.0 kg. The dogs were between 2.6 and 65.5 (median 10.3, mean 14.30 ± 14.51) months old (Table 1). Twenty-two dogs had reached maturity, and only 7 (32%) of these dogs weighted less than 13.0 kg. If considered clinically necessary, dogs were treated with ß-methyldigoxina (0.005 mg/kg PO q12h); furosemideb (1.0-2.0 mg/kg PO q12h); and/or ramiprilc (0.125 mg/kg PO q24h) prior to catheterization and angiography.
Journal of Veterinary Cardiology, Vol.5, No. 2, November 2003
PDA measurements One picture which best showed the PDA morphology was selected and scanned to handle in a personal computer. PDA morphology was classified to an adapted human scoring system11 without subclassification (Figure 2). Briefly, the following types exist; type A: narrowest segment at the pulmonary insertion, with a well-defined ampulla at the aortic end; type B: short and narrowed at the aortic insertion; type C: tubular, without constriction, type D: multiple constrictions; type E: elongated conical appearance with a constriction remote from the ventral border of the trachea.
Figure 3 shows the PDA measurements: the diameter of the PDA at the connection to the main pulmonary artery = minimal diameter (a); the diameter of the PDA ampulla in the middle of the vessel (b); the ampulla length at the cranial border (c); and the angle between descending aorta and ductal ampulla. All measurements were done to the nearest 0.1 mm by magnification correction in comparison to the radiodense scale. In 8 dogs measurements were made using both the radiodense scale on the table and a radiographic marker catheter in the descending aorta, allowing for comparison of the two methods and calculation of the percent difference. To describe the PDA morphology more exactly, the ratios of ampulla diameter to minimal PDA diameter and ampulla length to ampulla diameter were calculated. Post angiography different coil-systems were used to close the PDA under the same anesthesia. In dogs with an arterial approach, angiography was repeated after successful embolization. At the end of catheter intervention, the puncture site of the femoral vein was compressed manually
In 41/43 dogs (95 %) weighing ≥ 3.0 kg the percutaneous right brachial arterial approach was successful using a 3F (n=4), 4F (n=17), 5F (n=17) or 6F (n=3) introducer. In two dogs placing the guide wire into the vessel proved impossible after puncturing the brachial artery. A small haematoma precluded further puncture of the brachial artery and a percutaneous right femoral artery approach was selected. Two dogs with severe congestive heart failure and atrial fibrillation died during catheter intervention, therefore only 39 patients could be evaluated for complications. Two dogs displayed radial nerve paralysis after the procedure but recovered normal neurologic function after 4 and 6 days without treatment. No dog experienced arterial hemorrhage. Percutaneous access to the femoral vein with antegrade catheterization of the PDA was achieved in all six dogs weighing less than 3.0 kg. No complications were experienced with the venous approach. PDA morphology and dimensions The PDA extended from the ventral margin of the descending aorta to the cranial border of the main pulmonary artery (MPA) near its bifurcation in all dogs. The mean angle between descending aorta and PDA was 148.8 ± 7.6 degree (range 117 – 164). All but one PDA had a wide ampulla at the aortic orifice and a constriction at the insertion to the MPA. The most frequently encountered PDA-type was E (elongated conical, n=39, 80%), followed by type A (conical, n=9, 18%). Only one dog (2%) had a type D (two constrictions) (see Figure 4). No dog had a tubular duct (type C) or a ductus with a constriction at the aortic site only (type B). 23
Matthias Schneider; Ingo Schneider; Nicolai Hildebrandt; Martin Wehner
C
Figure 4 - Examples of different catheter placement and PDA-types
A
A) The angiographic catheter is placed from the brachial artery (a), through the brachiocephalic trunk into the descending aorta. The PDA (b) has an elongated conical form with a well-defined constriction (c) at the insertion to the MPA (type E).
C) The angiographic catheter is placed from the brachial artery. The PDA has two constrictions one at the pulmonic (a) and one at the aortic (b) site (type D).
The minimal PDA diameter had a mean dimension of 3.79 ± 1.55 mm (range 1.5 to 6.9, median 3.4). In 20/49 dogs (41%) the minimal PDA diameter measured more than 4.0 mm. There was a significant correlation (Pearson, r = 0.6523, p < 0.0001) between body weight and minimal PDA diameter (see Figure 5).
B
PDA minimal diameter (mm)
Figure 5 - Linear association of PDA minimal diameter (mm) and body weight. The solid line represents the line of best fit, the inner dashed lines represents the 95% confidence intervals for the line of best fit and the outer dashed lines represents the 95% prediction interval for the observation.
B) The catheter is placed from the femoral vein through the right heart antegrade through the PDA into the descending aorta. The PDA (a) is short with a constriction (b) at the pulmonic site (type A).
Table 1 - Patients data and angiographic dimensions of the PDA in 49 dogs. parameter patients data: age (mo) body weight (kg) angiographic measurements: angle between aorta and PDA (degree) minimal diameter (mm) ampulla diameter (mm) ampulla length (mm) ratios: ampulla diameter to minimal diameter ampulla length to ampulla diameter
24
range
median
mean
SD
normal distribution
2.6 - 65.5 1.5 - 50.0
10.3 11.5
14.30 15.73
14.52 12.04
no yes
117 - 164 1.5 - 6.9 3.9 - 15.9 3.9 - 22.5
150 3.4 8.0 11.3
148.80 3.79 8.57 11.84
7.60 1.55 2.98 4.48
yes yes yes yes
1.6 - 4.1 0.5 - 2.6
2.3 1.4
2.37 1.43
0.45 0.45
yes yes
Matthias Schneider; Ingo Schneider; Nicolai Hildebrandt; Martin Wehner
Journal of Veterinary Cardiology, Vol.5, No. 2, November 2003 Twenty-six dogs with a body weight less than 13.0 kg had a mean PDA minimal diameter of 2.72 ± 0.74 mm (range 1.4 – 4.3) and one (4%) of these had a PDA minimal diameter more than 4.0 mm. In contrast 23 dogs weighing 13.0 kg or more had a mean PDA minimal diameter of 5.00 ± 1.31 mm (range 1.7 – 6.9) and 19 (83%) had a PDA minimal diameter more than 4.0 mm. The difference between the two groups was significant (p < 0.0001).
C
Figure 4 - Examples of different catheter placement and PDA-types
A
Correlation between minimal diameter and age was not significant (Spearman, p = 0.0710). There was no significant difference of PDA minimal diameter between male (n = 19) and female dogs (n = 30, p = 0.9918) nor between dogs with type A (n = 9) and type E ductus (n = 39, p = 0.2661).
A) The angiographic catheter is placed from the brachial artery (a), through the brachiocephalic trunk into the descending aorta. The PDA (b) has an elongated conical form with a well-defined constriction (c) at the insertion to the MPA (type E).
C) The angiographic catheter is placed from the brachial artery. The PDA has two constrictions one at the pulmonic (a) and one at the aortic (b) site (type D).
The minimal PDA diameter had a mean dimension of 3.79 ± 1.55 mm (range 1.5 to 6.9, median 3.4). In 20/49 dogs (41%) the minimal PDA diameter measured more than 4.0 mm. There was a significant correlation (Pearson, r = 0.6523, p < 0.0001) between body weight and minimal PDA diameter (see Figure 5).
B
PDA minimal diameter (mm)
Figure 5 - Linear association of PDA minimal diameter (mm) and body weight. The solid line represents the line of best fit, the inner dashed lines represents the 95% confidence intervals for the line of best fit and the outer dashed lines represents the 95% prediction interval for the observation.
B) The catheter is placed from the femoral vein through the right heart antegrade through the PDA into the descending aorta. The PDA (a) is short with a constriction (b) at the pulmonic site (type A).
Table 1 - Patients data and angiographic dimensions of the PDA in 49 dogs. parameter patients data: age (mo) body weight (kg) angiographic measurements: angle between aorta and PDA (degree) minimal diameter (mm) ampulla diameter (mm) ampulla length (mm) ratios: ampulla diameter to minimal diameter ampulla length to ampulla diameter
24
range
median
mean
SD
normal distribution
2.6 - 65.5 1.5 - 50.0
10.3 11.5
14.30 15.73
14.52 12.04
no yes
117 - 164 1.5 - 6.9 3.9 - 15.9 3.9 - 22.5
150 3.4 8.0 11.3
148.80 3.79 8.57 11.84
7.60 1.55 2.98 4.48
yes yes yes yes
1.6 - 4.1 0.5 - 2.6
2.3 1.4
2.37 1.43
0.45 0.45
yes yes
Mean diameter of the PDA ampulla was 8.57 ± 2.98 mm (range 3.8 - 15.9). Ratio of PDA ampulla diameter to PDA minimal diameter was 1.6 up to 4.1 (2.37 ± 0.45) and was not significantly (p = 0.7209) different between type E and type A ductus. In 39/49 (80%) dogs the ampulla was at least was two times bigger than the minimal diameter. Only two dogs had a ratio less than 1.8. The mean length of ampulla was 11.84 ± 4.48 mm (range 3.9 and 22.5). Ratio between ampulla length and diameter ranged between 0.5 - 2.6 (1.43 ± 0.45). 43/49 (88%) dogs had a ratio of 1.0 or more. The measurement with the radiographic scale on the table underestimated the measurement with marker catheter by 5%, 6%, 6%, 7% in 4 large dogs (≥ 13.0 kg) and by 2%, 2%, 3%, 3% in 4 small (< 13.0 kg) dogs.
Discussion This study shows that percutaneous approach to the brachial artery is possible in most dogs weighing more than 3.0 kg body weight and that the procedure has a minimal risk of haemorrhage. The high success (95%) of percutaneous brachial arterial catheterization may have been facilitated by the hyperkinetic pulse in dogs with a PDA, and should be studied in dogs with other indications for left heart catheterization. No bleeding appeared in 39 cases of brachial artery puncture in contrast to substantially higher rates when the femoral artery was used5,13,14. The proximity of the brachial artery to the humerus with only a small amount of interposed soft tissue permits effective compression of the vessel when bandaged. Secondly, the bandage could be fastened around the shoulder to avoid distal displacement. Two large dogs showed a disturbance of the radial nerve after the puncture of brachial artery. The probable cause may be a injury of the nerve during arterial puncture, compression of the nerve by the introducer or by a bandage fastened too tightly. Catheterization via the brachial artery has a second advantage in comparison to the femoral artery given the shorter distance and improved catheter angle18 in that it is relatively easy to catheterise the left ventricle. Additionally, by using a shorter catheter, it is possible to reduce the catheter diameter without reduction of maximal flow rate. Disadvantages of brachial artery catheterization include the small vessel diameter and limited ability to access a patent ductus arteriosus for transcatheter occlusion.
For small dogs (< 3.0 kg) it is possible, to dispense with an arterial approach and obtain access via the femoral vein. There are however some disadvantages of this procedure. In very small dogs it can be difficult to place the catheter from the femoral vein through the right heart and to arrive at the PDA antegrade from the main pulmonary artery (MPA). Moreover, it is not possible to accomplish an arterial angiography after attempted PDA occlusion. In all six small dogs studied here there it was no problem advancing the catheter antegrade into the ductus, and because the PDA were small, control angiography was not necessary. While not performed in this study, one could inject contrast medium into the MPA and evaluate ductal patency during the levo phase of the angiogram before and after an coil embolization. Alternatively, angiography could be replaced by color-Doppler echocardiographic examination after the embolization procedure19. The angle between descending aorta and PDA (range 117 – 164 degree) was larger than in a human study (range 80 – 139 degree)20. By this angle it is nearly impossible to advance a catheter from the brachial or carotid artery through the PDA into the MPA, therefore PDA occlusion using approach from this artery is not possible. The forms of PDA, we observed were similar to those reported in human studies and other studies in dogs, but the distribution of the types is different. In humans type A (65%) is frequent and type E (6%) is rare11. Similar distributions could be found in the most human studies, but there seem to be regional differences also, because in a study from southern Europe the type E (39%) was more frequent than type A (33%)21. We found the type E in 80% and type A in 18% of the dogs. The elongated conical form (type E) was also the most frequent type in the USA (43% called as type IIa12). The frequency of tubular ductus (without a constriction, type C) is of special importance, because it is very difficult to embolize such a ductus. In human medicine the number is low (8%)11 and we did not observe any PDA with this morphology. Miller and colleagues12 found the tubular ductus type in dogs, but did not told the exact number. Stokhof and colleagues7 also described PDA morphology in dogs but not according with the classification scheme of Krichenko and colleagues11. The authors described a “tubular duct” in 7/15 dogs, but they classified the PDA as “type E” in 6 of them (elongated conical according Krichenko and colleagues11). In some human studies the type E ducts is incorrectly referred to as “tubular, with pulmonary constriction”22. One reason why we did not found any tubular ductus might be our selection of PDA with left to right shunt, because many of the tubular PDA develop a right to left shunt during the first months of the life23,24. In prior studies, there was no significant correlation between the minimal ductal diameter and patient body weight or age either in humans11 or in dogs12. We found a significant correlation between PDA minimal diameter and body weight, but not to age. A possible reason is, that none of our dogs had a tubular duct, which have a significant larger diameter than other PDA types12. Additionally a higher number of large dogs improves the likelihood of demonstrating a correlation between PDA minimal diameter 25
Matthias Schneider; Ingo Schneider; Nicolai Hildebrandt; Martin Wehner and body weight. In this study the body weight (15.73 ± 12.04 kg, median 11.5 kg) was high compared to American studies (7.6 ± 5.8 kg12, median 7.5 kg25), and only 32% of the dogs which had reached maturity had a body weight less than < 13.0 kg, compared to 85% in a large American study26. These differences can be explained by the high percentage of large breed dogs, like German Shepherd (31%) in our study. In an English study15 with 20% German Shepherds the median body weight (12.5 kg) was higher than in the American studies and only minimal lower than in this study. The mean PDA minimal diameter in our study was 3.79 ± 1.55 which is similar to another study in dogs (3.8 ± 2.2)12 but larger than in humans (3.2 ± 1.0)11. A PDA larger than 4.0 mm is observed in only 20% of the human patients11 but in 41% of the dogs in this study. Such large PDA are difficult to occlude by means of coil techniques and these dogs often require some other occlusion system. Given the relation between body weight and PDA minimal diameter and the high number of small breed dogs (85% less than 13.0 kg at maturity)26 in the USA, the percentage of dogs with a PDA more than 4.0 mm might be much lower in the USA than in our study. In a human study27 it was found that the PDA is not a fixed structure. It could be stretched to twice the size of angiographic minimal diameter by a soft latex balloon. This may be one reason why Lloyd and colleagues28 proposed using a coil loop diameter two times bigger than the PDA minimal diameter. In our dogs the ratio between PDA ampulla and minimal diameter was near or about two and all PDA had a constriction at pulmonic site suggesting that it is possible to place a occlusion system with spherical form and a diameter two times the PDA minimal diameter. Because in most dogs the PDA ampulla length is larger than the diameter, a spherical occlusion device should not project into the descending aorta. There are several available methods to correct the magnification of a fluoroscopy machine. The most exact way is to use a marker at the level of the vessel29. The best method is to use a special angiographic catheter with two ore more radiographic markers, normally 1 or 2 cm apart. Many human studies simply use the diameter of the angiographic catheter as reference30-32, but it is not easy to measure the catheter diameter exactly and a 0.1 mm error using a 5F (1.66 mm) or 4F (1.33 mm) catheter leads to 6% or 8% failure in all dimensions. Other authors use a scale on the table7 or on the chest33. If the radiographic scale is not on the same level as the vessel (like PDA), it is a potential source for failure in measurements. In our study the scale was on the table and the films are recorded above the dog, leading to underestimation of the true dimensions. However it could be shown by comparison to a radiographic marker catheter, that this error is low in small dogs (2-3%) and in larger dogs also (5-7%).
Study limitation We used only lateral projections for measuring the PDA dimensions. This procedure is also done in the most human11 and veterinary7,12 studies because in the dorso-ventral projection the aorta overlaps the PDA, making it impossible 26
to judge the PDA morphology and to measure the PDA dimensions. Measurement in a single plane may cause slight underestimation of the correct value of PDA minimal diameter4,7 and this has to be taken in account when performing a PDA embolization. a Lanitop, Boeringer Mannheim, Mannheim, Germany b Lasix, Hoechst, Frankfurt, Germany c Delix, Hoechst, Frankfurt, Germany d Polamivet, Hoechst Roussel Vet, Unterschleissheim, Germany e Valium, Hoffmann-La Roche AG, Grenzach-Wyhlen, Germany f Forene, Abbot GmbH, Wiesbaden, Germany g Ultrasonic Doppler Flow Detector Model 811, Parks electronics, Aloha, Ore h Conray 70, Mallinckrodt Hennef, Hennef Sieg, Germany i Angiomat 3000, Angiomed GmbH, Karlsruhe, Germany j Augmentan SmithKline Beecham, Bönen, Germany or Synulox, Pfizer GmbH, Karlsruhe, Germany k GraphPad Prism 3.0, GrapPad Software, Inc, San Diego, USA
References 1. Snaps FR, McEntee K, Saunders JH, Dondelinger RF. Treatment of patent ductus arteriosus by placement of intravascular coils in a pup. J Am Vet Med Assoc 1995; 207: 724-725. 2. Grifka RG, Miller MW, Frischmeyer KJ, Mullins CE. Transcatheter occlusion of a patent ductus arteriosus in a Newfoundland puppy using the Gianturco-Grifka vascular occlusion device. J Vet Intern Med 1996; 10: 42-44. 3. Fellows CG, Lerche P, King G, Tometzki A. Treatment of patent ductus arteriosus by placement of two intravascular embolisation coils in a puppy. J Small Anim Pract 1998; 39: 196-199. 4. Fox PR, Bond BR, Sommer RJ. Nonsurgical transcatheter coil occlusion of patent ductus arteriosus in two dogs using a preformed nitinol snare delivery technique. J Vet Intern Med 1998; 12: 182-185. 5. Glaus TM, Gardelle O, Bass M, Kiowski WK. Verschluss eines persistierenden ductus arteriosus botalli bei zwei hunden mittels transarterieller coil-embolisation. Schweiz Arch Tierheilk 1999; 141: 191-194. 6. Saunders JH, Snaps FR, Peeters D, et al. Use of a balloon occlusion catheter to facilitate transarterial coil embolisation of a patent ductus arteriosus in two dogs. Vet Rec 1999; 145: 544-546. 7. Stokhof AA, Sreeram N, Wolvekamp WT. Transcatheter closure of patent ductus arteriosus using occluding spring coils. J Vet Intern Med 2000; 14: 452-455. 8. Schneider M, Hildebrandt N, Schweigl T, et al. Transvenous embolization of small patent ductus arteriosus with single detachable coils in dogs. J Vet Intern Med 2001; 15: 222-228. 9. Buchanan JW, Patterson DF. Selective angiography and angiocardiography in dogs with congenital cardiovascular disease. J Am Vet Rad Soc 1965; 6: 21-39. 10. Bonagura JD, Darke PGG. Congenital heart disease. In Ettinger SJ, Feldman EC ed. Textbook of Veterinary Internal Medicine. Philadelphia, WB Saunders; 1994: 892-943. 11. Krichenko A, Benson LN, Burrows P, et al. Angiographic classification of the isolated, persistently patent ductus arteriosus and implications for percutaneous catheter occlusion. Am J Cardiol 1989; 63: 877-880. 12. Miller MW, Meurs KM, Lehmkuhl LB, et al. Angiographic classification of patent ductus arteriosus in the dog.
Matthias Schneider; Ingo Schneider; Nicolai Hildebrandt; Martin Wehner and body weight. In this study the body weight (15.73 ± 12.04 kg, median 11.5 kg) was high compared to American studies (7.6 ± 5.8 kg12, median 7.5 kg25), and only 32% of the dogs which had reached maturity had a body weight less than < 13.0 kg, compared to 85% in a large American study26. These differences can be explained by the high percentage of large breed dogs, like German Shepherd (31%) in our study. In an English study15 with 20% German Shepherds the median body weight (12.5 kg) was higher than in the American studies and only minimal lower than in this study. The mean PDA minimal diameter in our study was 3.79 ± 1.55 which is similar to another study in dogs (3.8 ± 2.2)12 but larger than in humans (3.2 ± 1.0)11. A PDA larger than 4.0 mm is observed in only 20% of the human patients11 but in 41% of the dogs in this study. Such large PDA are difficult to occlude by means of coil techniques and these dogs often require some other occlusion system. Given the relation between body weight and PDA minimal diameter and the high number of small breed dogs (85% less than 13.0 kg at maturity)26 in the USA, the percentage of dogs with a PDA more than 4.0 mm might be much lower in the USA than in our study. In a human study27 it was found that the PDA is not a fixed structure. It could be stretched to twice the size of angiographic minimal diameter by a soft latex balloon. This may be one reason why Lloyd and colleagues28 proposed using a coil loop diameter two times bigger than the PDA minimal diameter. In our dogs the ratio between PDA ampulla and minimal diameter was near or about two and all PDA had a constriction at pulmonic site suggesting that it is possible to place a occlusion system with spherical form and a diameter two times the PDA minimal diameter. Because in most dogs the PDA ampulla length is larger than the diameter, a spherical occlusion device should not project into the descending aorta. There are several available methods to correct the magnification of a fluoroscopy machine. The most exact way is to use a marker at the level of the vessel29. The best method is to use a special angiographic catheter with two ore more radiographic markers, normally 1 or 2 cm apart. Many human studies simply use the diameter of the angiographic catheter as reference30-32, but it is not easy to measure the catheter diameter exactly and a 0.1 mm error using a 5F (1.66 mm) or 4F (1.33 mm) catheter leads to 6% or 8% failure in all dimensions. Other authors use a scale on the table7 or on the chest33. If the radiographic scale is not on the same level as the vessel (like PDA), it is a potential source for failure in measurements. In our study the scale was on the table and the films are recorded above the dog, leading to underestimation of the true dimensions. However it could be shown by comparison to a radiographic marker catheter, that this error is low in small dogs (2-3%) and in larger dogs also (5-7%).
Study limitation We used only lateral projections for measuring the PDA dimensions. This procedure is also done in the most human11 and veterinary7,12 studies because in the dorso-ventral projection the aorta overlaps the PDA, making it impossible 26
to judge the PDA morphology and to measure the PDA dimensions. Measurement in a single plane may cause slight underestimation of the correct value of PDA minimal diameter4,7 and this has to be taken in account when performing a PDA embolization. a Lanitop, Boeringer Mannheim, Mannheim, Germany b Lasix, Hoechst, Frankfurt, Germany c Delix, Hoechst, Frankfurt, Germany d Polamivet, Hoechst Roussel Vet, Unterschleissheim, Germany e Valium, Hoffmann-La Roche AG, Grenzach-Wyhlen, Germany f Forene, Abbot GmbH, Wiesbaden, Germany g Ultrasonic Doppler Flow Detector Model 811, Parks electronics, Aloha, Ore h Conray 70, Mallinckrodt Hennef, Hennef Sieg, Germany i Angiomat 3000, Angiomed GmbH, Karlsruhe, Germany j Augmentan SmithKline Beecham, Bönen, Germany or Synulox, Pfizer GmbH, Karlsruhe, Germany k GraphPad Prism 3.0, GrapPad Software, Inc, San Diego, USA
References 1. Snaps FR, McEntee K, Saunders JH, Dondelinger RF. Treatment of patent ductus arteriosus by placement of intravascular coils in a pup. J Am Vet Med Assoc 1995; 207: 724-725. 2. Grifka RG, Miller MW, Frischmeyer KJ, Mullins CE. Transcatheter occlusion of a patent ductus arteriosus in a Newfoundland puppy using the Gianturco-Grifka vascular occlusion device. J Vet Intern Med 1996; 10: 42-44. 3. Fellows CG, Lerche P, King G, Tometzki A. Treatment of patent ductus arteriosus by placement of two intravascular embolisation coils in a puppy. J Small Anim Pract 1998; 39: 196-199. 4. Fox PR, Bond BR, Sommer RJ. Nonsurgical transcatheter coil occlusion of patent ductus arteriosus in two dogs using a preformed nitinol snare delivery technique. J Vet Intern Med 1998; 12: 182-185. 5. Glaus TM, Gardelle O, Bass M, Kiowski WK. Verschluss eines persistierenden ductus arteriosus botalli bei zwei hunden mittels transarterieller coil-embolisation. Schweiz Arch Tierheilk 1999; 141: 191-194. 6. Saunders JH, Snaps FR, Peeters D, et al. Use of a balloon occlusion catheter to facilitate transarterial coil embolisation of a patent ductus arteriosus in two dogs. Vet Rec 1999; 145: 544-546. 7. Stokhof AA, Sreeram N, Wolvekamp WT. Transcatheter closure of patent ductus arteriosus using occluding spring coils. J Vet Intern Med 2000; 14: 452-455. 8. Schneider M, Hildebrandt N, Schweigl T, et al. Transvenous embolization of small patent ductus arteriosus with single detachable coils in dogs. J Vet Intern Med 2001; 15: 222-228. 9. Buchanan JW, Patterson DF. Selective angiography and angiocardiography in dogs with congenital cardiovascular disease. J Am Vet Rad Soc 1965; 6: 21-39. 10. Bonagura JD, Darke PGG. Congenital heart disease. In Ettinger SJ, Feldman EC ed. Textbook of Veterinary Internal Medicine. Philadelphia, WB Saunders; 1994: 892-943. 11. Krichenko A, Benson LN, Burrows P, et al. Angiographic classification of the isolated, persistently patent ductus arteriosus and implications for percutaneous catheter occlusion. Am J Cardiol 1989; 63: 877-880. 12. Miller MW, Meurs KM, Lehmkuhl LB, et al. Angiographic classification of patent ductus arteriosus in the dog.
Journal of Veterinary Cardiology, Vol.5, No. 2, November 2003 23. Patterson DF, Pyle RL, Buchanan JW, et al. Hereditary patent ductus arteriosus and its sequelae in the dog. Circ Res 1971; 29: 1-13. 24. Pyle RL, Park RD, Alexander AF, Hill BL. Patent ductus arteriousus with pulmonary hypertension in the dog. J Am Vet Med Assoc 1981; 178: 565-571. 25. Birchard SJ, Bonagura JD, Fingland RB. Results of ligation of patent ductus arteriosus in dogs: 201 cases (1969-1988). J Am Vet Med Assoc 1990; 196: 2011-2013. 26. Eyster GE, Eyster JT, Cords GB, Johnston J. Patent ductus arteriosus in the dog: characteristics of occurence and results of surgery in one hundred consecutive cases. J Am Vet Med Assoc 1976; 168: 435-438. 27. Tomita H, Fuse S, Chiba S. Stretched minimal diameter of the ductus and coil occlusion. Acta Paediatr Jpn 1998; 40: 453-456. 28. Lloyd TR, Fedderly R, Mendelsohn AM, et al. Transcatheter occlusion of patent ductus arteriosus with Gianturco coils. Circulation 1993; 88: 1412-1420. 29. Sharafuddin MJA, Gu X, Titus JL, et al. Experimental evaluation of a new self-expanding patent ductus arteriosus occluder in a canine model. J Vasc Interv Radiol 1996; 7: 877-887. 30. Sahn DJ, Allen HD. Real-time cross-sectional echocardiographic imaging and measurement of the patent ductus arteriosus in infants and children. Circulation 1978; 58: 343-354. 31. Dalvi B, Goyal V, Narula D, et al. New technique using temporary balloon occlusion for transcatheter closure of patent ductus arteriosus with Gianturco coils. Cathet Cardiovasc Diagn 1997; 41: 62-70. 32. Wong JA, Shim D, Khoury PR, Meyer RA. Validation of color Doppler measurements of minimum patent ductus arteriosus diameters: significance for coil embolization. Am Heart J 1998; 136: 714-717. 33. Hijazi ZM. New closure devices for left-to-right shunt. Indian Heart J 1996; 48: 119-123.
Proceedings of the 16th ACVIM forum 1998: 244. 13. Kienle RD. Cardiac Catheterization. In Kittleson MD, Kienle RD ed. Small Animal Cardiovascular Medicine. St. Louis, Mosby, Inc; 1998: 118-132. 14. Miller MW, Meurs KM, Gordon SG, Spangler EA. Transarterial ductal occlusion using Gianturco vascular occlusion coils: 43 cases 1994-1998. J Vet Intern Med 1999; 13: 247. 15. Van Israel N, French AT, Dukes-McEwan J, Corcoran BM. Review of left-to-right shunting patent ductus arteriosus and short term outcome in 98 dogs. J Small Anim Pract 2002; 395-400. 16. Thomas WP, Sisson D. Cardiac catheterization and angiocardiography. In Fox PR, Sisson D, Moise NS ed. Textbook of Canine and Feline Cardiology: Principles and Clinical Practice. Philadelphia, WB Saunders; 1999: 173192. 17. Gerlach K, Skrodzki M, Trautvetter E. Kongenitale anomalien des aortenbogens beim Hund (I). Kleintierpraxis 1988; 33: 355-363. 18. Bonagura JD, Lehmkuhl LB. Congenital heart disease. In Fox PR, Sisson D, Moise NS ed. Canine and Feline Cardiology. Philadelphia, WB Saunders Company; 1999: 471-535. 19. Uzun O, Hancock S, Parsons JM, et al. Transcatheter occlusion of the arterial duct with Cook detachable coils: early experience. Heart 1996; 76: 269-273. 20. Abrams SE, Walsh KP. Arterial duct morphology with reference to angioplasty and stenting. Int J Cardiol 1993; 40: 27-33. 21. Bermudez CR, Velasco BJ, Herraiz JI, et al. Therapeutic catheterization: the percutaneous closure of a persistent ductus arteriosus and of interatrial communication. Rev Esp Cardiol 1992; 45: 42-50. 22. Belau L, Grävinghoff L, Keck EW. Verschluß des persistierenden ductus arteriousus Botalli ohne thorakotomie. Dtsch Med Wochenschr 1993; 118: 169-175.
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Journal of Veterinary Cardiology Official Journal of the European Society of Veterinary Cardiology Visit us at http://www/esvc.net/ Please notice that the editorial office is now in Paris: Pr Valérie Chetboul, Editorial Office, Journal of Veterinary Cardiology Unité de Cardiologie d'Alfort - UP de Médecine, ENVA 7 av. du Gal de gaulle - 94704 Maisons-Alfort cédex - France
Next meetings: ESVC/ECVIM-CA (info at: http://www.ecvim-ca.org/)
14th ECVIM-CA congress 2004 Congress Information: Barcelona, Spain. September 9-11 The congress will take place at the Autonomous University of Barcelona which is situated 25 minutes from the center of Barcelona.
ESVC precongress Pre-congress day, September 8, 2004 For informations, please contact Maria Fernandez del Palacio: [email protected] Hospital Clínico Veterinario, Universidad de Murcia, Facultad de Veterinaria 30100- Espinardo. Murcia. Spain - Phone. 34 968 364723
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