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End-to-end repair of aortic coarctation using absorbable polydioxanone suture
End-to-End Repair of Aortic Coarctation Using Absorbable Polydioxanone Suture Juan D. Arenas, MD, John L. Myers, MD, Marie M. Gleason, MD, Alexander Vennos, MD, Barry G. Baylen, MD, and John A. Waldhausen, MD Departments of Surgery, Pediatrics, and Radiology, College of Medicine, The Pennsylvania State University, Hershey, Pennsylvania
Based on previous laboratory work, we have used polydioxanone absorbable suture in a variety of vascular and cardiac repairs in pediatric patients. However, some investigators have expressed concern about the potential for aneurysm formation at the anastomotic site. Between March 1983 and June 1989, 15 patients (7male, 8 female) aged 2.5 months to 9.2 years (mean, 3.7 years) had resection of coarctation of the aorta and end-to-end anastomosis with polydioxanone absorbable suture. Thirteen patients have returned for routine postoperative evaluation, the follow-up time ranging from 11 to 49
months (mean, 23 months). Noninvasive two-dimensional, pulsed-wave Doppler and color echocardiography and magnetic resonance imaging studies demonstrated good anatomical repair and no anastomotic aneurysm formation or residual coarctation of the aorta in any patient after end-to-end anastomosis with polydioxanone. In summary, this intermediate follow-up study has revealed no vascular complications related to the repair of coarctation with absorbable polydioxanone suture. (Ann Thorac Surg 1991;51:413-7)
0
ne long-term complication after surgical repair of coarctation of the aorta (CoA) is residual or recurrent coarctation. Different suture materials have been employed in an attempt to avoid this problem [l, 21. In general, we perform subclavian flap angioplasty in neonates and most infants with aortic coarctation who are less than 1 year of age [3]. Older children usually undergo resection of the coarctation and end-to-end anastomosis. Previously published work shows the advantages of polydioxanone (PDS), an absorbable monofilament suture, over polypropylene (Prolene), a nonabsorbable monofilament suture, in growing anastomoses [l, 2, 41. These studies demonstrated that PDS allows the vascular anastomoses to grow. Since 1983, we have used PDS suture in a variety of cardiovascular procedures [4]. However, some concerns have been expressed regarding aneurysm formation at the vascular anastomotic site when absorbable sutures are used [5]. This report describes the results in 15 consecutive patients who had resection of CoA and end-to-end anastomosis using PDS absorbable suture.
tomosis using PDS monofilament absorbable suture at The Milton S. Hershey Medical Center. Seven patients were male and 8 were female. Their weight at operation ranged from 5 to 26.9 kg (mean 15.4 kg). Preoperative cardiac catheterization in 13 patients
Patients and Methods
Study Population Between March 1983 and June 1989, 15 patients aged 2.5 months to 9.2 years (mean, 3.7 years) had a surgical repair of CoA consisting of CoA resection and end-to-end anasAccepted for publication Oct 30, 1990. Address reprint requests to Dr Myers, Division of Cardiothoracic Surgery, College of Medicine, The Milton S . Hershey Medical Center, The Pennsylvania State University, PO Box 850, Hershey, PA 17033.
0 1991 by The Society of Thoracic Surgeons
Table 1. Preoperative Data Weight
Age at Operation
Sex
0%)
(Y)
7 8
F F F F F M M M
16.6 14.0 14.3 18.5 5.5 15.0 8.7 30.0
9
M
10.5
10 11 12 13 14 15
M M
5.0 19.5 13.0 25.0 15.7 26.9
6.1 2.3 3.0 4.6 0.7 3.8 1.0 7.3 1.4 0.2 5.2 1.8 7.8 4.2 9.2
15.1 2.1
4.9 0.8
Patient No.
1 2 3 4 5 6
F M F F
Mean SEM SEM
=
Catheterization Gradient (mm Hg)
20
... 70 50 35 35 45 50 50
... ... 30 30 40 50 42.7 3.6
standard error of the mean.
0003-4975/91/$3.50
414
ARENAS ET AL COARCTATION OF THE AORTA
showed CoA gradients that ranged from 30 to 70 mm Hg (mean, 43 mm Hg). Mean age at catheterization was 3.6 years. Associated cardiac anomalies were ventricular septal defect in 3 patients, patent ductus arteriosus in 1 patient, and bicuspid aortic valve in 6 patients. One patient had patent ductus arteriosus ligation before CoA repair (Table 1).
Operative Technique Through a left fourth intercostal space thoracotomy, the entire aorta from the aortic arch to the diaphragm was mobilized. The patent ductus arteriosus or ligamentum arteriosum was ligated before excision of the CoA segment. An end-to-end anastomosis was performed with continuous PDS sutures on the posterior aspect of the aorta and interrupted PDS sutures on its anterior aspect. The aortic cross-clamp time ranged from 18 to 50 minutes (mean, 34 minutes).
Postoperative Management A right radial artery catheter was used to monitor blood pressure continuously. Sodium nitroprusside and intravenous propranolol or esmolol were used to control systemic hypertension in the immediate postoperative period to maintain peak systolic blood pressure at between 100 and 110 mm Hg. If hypertension persisted, regimens of oral captopril or propranolol or both were begun on the day after operation. Urine output was measured, blood chemistry tests for renal function were done, and stool was tested postoperatively for occult blood.
Intermediate-Term Evalua tion Thirteen patients returned to the pediatric cardiology clinic for routine postoperative evaluation. Two patients did not show up for their follow-up appointments. They were both well, as could be determined by telephone assessment. Follow-up ranged from 11 to 49 months (mean, 23 months) postoperatively. Electrocardiograms, chest radiographs, and routine physical examination including blood pressure measurements were obtained in all patients. Complete two-dimensional, pulsed-wave Doppler and color flow mapping echocardiography was performed successfully in 12 of the 13 patients using a Vingmed CFM 500 (Interspec, Inc, Ambler, PA) ultrasound system. Imaging and Doppler echocardiography were performed with 5.0- and 3.0-MHz phased array transducers. One patient could not be adequately sedated for noninvasive testing. Chloral hydrate sedation (60 to 100 mg/kg orally) was administered to the patients less than 3 years of age who were unable to cooperate. The aortic arch and the site of repair were imaged from the suprasternal notch to evaluate for residual CoA or anastomotic aneurysm. Ascending and descending aortic velocities were measured with high pulse repetition frequency pulsed-wave and continuous-wave Doppler echocardiography. Successful magnetic resonance imaging of the aortic arch was completed in 11 of the 13 patients, using a
Ann Thorac Surg 1991;51:41>7
Siemens Magnetom 1.O-Telsa scanner (Siemens Medical Systems, Inc, Islan, NJ). Chloral hydrate sedation was administered to uncooperative patients less than 6 years of age. Parental permission was obtained for the magnetic resonance imaging scan. One patient could not be adequately sedated and 1 patient did not show up for his appointment at the magnetic resonance imaging facility.
Results Clinical Status On the first postoperative day, 6 patients had serious hypertension, which was treated with sodium nitroprusside and propranolol to lower the systolic arterial blood pressure to between 100 and 110 mm Hg. Subsequently, antihypertensive medication was required in 6 patients, 3 patients received captopril for 2 to 4 weeks, and 3 patients received p-blockers for 2 to 4 weeks. In all but 1 patient, antihypertensive medication was discontinued within 1 month postoperatively. This patient no longer required antihypertensive medication at 2 months postoperatively. Six months postoperatively, neither systolic nor diastolic hypertension was present in any patient. Postoperative urine output and renal function tests were normal in all patients. Finally, neither paraplegia nor symptoms of intestinal ischemia occurred in any patient. At the most recent examination, all patients were clinically well, had no cardiovascular symptoms, and were no longer taking any medications. Cardiac murmurs were audible at follow-up examination in the 3 patients with restrictive ventricular septal defects, in 2 patients with mitral valve prolapse and mild regurgitation, and in 6 patients with bicuspid aortic valves. All patients had normal peripheral artery pulses. Chest radiographs showed normal cardiac dimensions except for mild cardiomegaly in 1 child with a moderate ventricular septal defect. Eight of 13 patients had normal echocardiographic results; chest radiographs showed biventricular hypertrophy in the patient with a ventricular septal defect who had cardiomegaly. Right ventricular hypertrophy voltage criteria were present in 2 patients without residual CoA or associated aortic stenosis. One patient with mitral valve prolapse and mild mitral insufficiency had borderline left ventricular hypertrophy. One patient with a bicuspid aortic valve and mild aortic stenosis showed left-axis deviation and complete right bundle-branch block postoperatively.
Noninvasive Evaluation Two-dimensional echocardiography did not suggest anastomotic aneurysm formation in any patient, and no residual CoA was detected in any patient after end-to-end anastomosis with PDS. Three patients showed mild narrowing at the anastomotic site compared with the dimensions of the ascending and descending thoracic aorta. Bicuspid aortic valves were noted in 6 of the 12 patients studied. Mitral valve prolapse was detected in 2 patients and restrictive perimembranous ventricular septal defects in 3 patients.
Ann Thorac Surg 1991;51:413-7
ARENAS ET AL COARCTATION OF THE AORTA
415
Fig 1. (A) Two-dimensional echocardiogram and color flow mapping of the aortic arch from the suprasternal notch (patient 1). Blue indicates laminar blood flow away from the transducer. Black arrows indicate level of end-to-end anastornosis. (AAo = ascending aorta; DAo = descending aorta; cr = cranial; 1 = left; p = posterior; r = right pulmonay artery.) ( B ) Magnetic resonance image (sagittal view) of the aortic arch (patient 1 ) .
Fig 2. (A) Two-dimensional echocardiogram and color flow mapping of the aortic arch from the suprasternal notch (patient 5). Blue indicates laminar blood flow away from the transducer. Black arrows indicate level of end-to-end anastomosis. (AAo = ascending aorta; DAo = descending aorta; cr = cranial; 1 = left; p =posterior; r = right pulmona y artery.) (B)Magnetic resonance image (sagittal view) of the aortic arch (patient 5).
Doppler echocardiographic evaluation of the ascending and descending aortic velocities defined the degree of associated aortic valve stenosis or residual aortic arch
gradient using the modified Bernoulli equation [ 6 ] . Peak instantaneous aortic valve gradients ranged from 0 to 27 mm Hg (mean, 12 mm Hg) and peak instantaneous aortic
416
ARENAS ET AL COARCTATION OF THE AORTA
Ann Thorac Surg 1991;51:41%7
Table 2. Follow-Up Data Blood Dopp1er Follow- Arch Patient up Gradient No. (mo) (mm Hg) LVSF" 7 1 8 3 4 5 15 14 10 16 11 13 12
Mean
SEM a
49 40 31 27 27 26 22 14 13 12 12 11 11 25 3.12
9 0 9 16 0 10 17 5 13 0
0.43 0.42 0.38 0.50 0.58 0.50 0.43 0.46 0.47
...
0.46
10 17
...
8.75 2.34
... 0.39
to poststenotic dilatation from preoperative jet hemodynamics (Table 2).
Pres-
Other Defects
sure Other (mm Doppler Hg) AS AS
BAV BAV VSD, MVP BAV BAV
MR
...
...
... ...
VSD BAV
120/54 90150 90/50 104/60 90150 1101. . . 11470 10464 1001. . .
...
...
106/60
BAV, VSD
...
MVP
MR
95/60 102/. . . 104/58
0.468 0.021
Normal > 0.28.
AS = mild aortic stenosis; BAV = bicuspid aortic valve; LVSF = left ventricular shortening fraction; MR = mitral regurgitation; SEM = standard error of the mean; MVP = mitral valve prolapse; VSD = ventricular septa1 defect.
arch gradients were 10 mm Hg or less (mean, 5 mm Hg) in 9 patients. Numerous studies have documented that Doppler maximal instantaneous gradient determinations significantly overestimate the peak-to-peak catheter gradient, especially with mild to moderate gradients [7, 81. Four patients had instantaneous aortic arch gradients greater than 10 mm Hg (range, 13 to 17 mm Hg). Thus, there was no serious residual CoA in this group of patients. Color mapping allows better visualization of the thoracic descending aorta than two-dimensional imaging alone. Often, the descending aorta distal to the left subclavian artery may be difficult to image, making the evaluation of aneurysm or recurrent CoA less reliable. Color flow mapping of the aortic arch showed virtually normal laminar flow in the descending aorta (Figs l A , 2A) with minimal turbulence. Thus, the anatomy of the repair and blood flow characteristics were essentially normal in all patients postoperatively. Magnetic resonance imaging studies provided excellent visualization of the entire aortic arch in all patients, but was particularly specific in defining the borders of the descending aorta in the area of the anastomosis (Figs l B , 2B). In this group of patients, no aneurysm or recurrent CoA was noted on magnetic resonance imaging, thereby confirming the data obtained with two-dimensional echocardiography and color flow mapping. With this imaging technique, mild dilatation of the descending aorta distal to the suture line was noted in 5 patients and was attributed
Comment The use of absorbable suture material for vascular anastomoses allows growth of the vessel, which is necessary for a successful long-term result after surgical repair to prevent recoarctation in infants and children. A potential limitation of end-to-end repair with nonabsorbable suture is that it may limit normal growth at the anastomotic site and lead to recoarctation. The use of noninvasive magnetic resonance imaging and two-dimensional color Doppler echocardiography allows the evaluation of hemodynamics and anatomical repairs and provides a reliable method by which to gain the information necessary for the postoperative evaluation of these patients. Our previous experiments in a growing porcine model demonstrated that the use of PDS for vascular anastomoses provides a good anatomical repair, normal growth at the anastomotic site, and normal integrity during burst testing [l, 21. Nevertheless, questions have been raised regarding the risk of aneurysm formation at the anastomotic site when using absorbable PDS [5]. Our prior experiences with animal models and our current experiences with children using PDS to repair CoA indicate good anatomical repair, good integrity of the anastomotic site, and physiological laminar blood flow characteristics, as well as adequate arterial growth and absence of recoarctation for as long as 49 months postoperatively. These results indicate that PDS is an acceptable material for repair of CoA in infancy and childhood and should continue to be used for the repair of vascular anastomoses in other forms of congenital heart disease. Although a longer follow-up period, including periodical noninvasive assessments, will be required to determine the long-term integrity of aortic anastomoses with absorbable suture, the use of PDS absorbable suture has been shown to be safe and reliable in our clinical and experimental experience.
References 1. Myers JL, Pae WE Jr, Waldhausen JA, Pierce WS. Vascular anastomoses in growing vessels: comparison of absorbable polydioxanone and nonabsorbable polypropylene monofilament suture materials. Surg Forum 1981;32:339-41. 2. Myers JL, Waldhausen JA, Pae WE Jr, Abt AB, Prophet GA, Pierce WS. Vascular anastomoses in growing vessels. The use of absorbable sutures. Ann Thorac Surg 1982;34:529-37. 3. Waldhausen JA, Whitman V, Werner JC, Pierce WS. Surgical intervention in infants with coarctation of the aorta. J Thorac Cardiovasc Surg 1981;81:323-5. 4. Myers JL, Campbell DB, Waldhausen JA. The use of absorbable monofilament polydioxanone suture in pediatric cardiovascular operations. J Thorac Cardiovasc Surg 1986;92:771-5. 5. Van Rijk-Zwikker GL. The effect of polydioxanone and
Ann Thorac Surg 1991;51:41>7
Prolene on circular aortic sutures under tension. Ned Tijdschr Geneeskd 1986;130:801-2. 6. Hatle L, Brubakk A, Tromsdal A, Angelsen B. Non-invasive assessment of pressure drop in mitral stenosis by Doppler ultrasound. Br Heart J 1978;40:13140. 7. Currie F'J, Hagler DJ, Seward JB, et al. Instantaneous pressure
ARENAS ET AL COARCTATION OF THE AORTA
417
gradient: a simultaneous Doppler and dual catheter correlative study. J Am Coll Cardiol 1986;7800-6. 8. Smith MD, Dawson PL, Elion JL, et al. Systematic correlation of continuous wave Doppler and hemodynamic measurements in patients with aortic stenosis. Am Heart J 1986;lll: 245-52.
Notice From the American Board of Thoracic Surgery Regarding Trainees and Candidates for Certification Who Are Called to Military Service Related to the Persian Gulf Conflict The Board appreciates the concern of those who have received emergency call to military service. They may be assured that the Board will exercise the same sympathetic consideration as was given to candidates, in recognition of their special contribution to their country, during the Korean and Viet Nam conflicts with regard to dead-
lines, applications, examinations, and interruption of training.
Harvey W. Bender, Jr, M D Chairman The American Board of Thoracic Surgery
Based on previous laboratory work, we have used polydioxanone absorbable suture in a variety of vascular and cardiac repairs in pediatric patients. However, some investigators have expressed concern about the potential for aneurysm formation at the anastomotic site. Between March 1983 and June 1989, 15 patients (7male, 8 female) aged 2.5 months to 9.2 years (mean, 3.7 years) had resection of coarctation of the aorta and end-to-end anastomosis with polydioxanone absorbable suture. Thirteen patients have returned for routine postoperative evaluation, the follow-up time ranging from 11 to 49
months (mean, 23 months). Noninvasive two-dimensional, pulsed-wave Doppler and color echocardiography and magnetic resonance imaging studies demonstrated good anatomical repair and no anastomotic aneurysm formation or residual coarctation of the aorta in any patient after end-to-end anastomosis with polydioxanone. In summary, this intermediate follow-up study has revealed no vascular complications related to the repair of coarctation with absorbable polydioxanone suture. (Ann Thorac Surg 1991;51:413-7)
0
ne long-term complication after surgical repair of coarctation of the aorta (CoA) is residual or recurrent coarctation. Different suture materials have been employed in an attempt to avoid this problem [l, 21. In general, we perform subclavian flap angioplasty in neonates and most infants with aortic coarctation who are less than 1 year of age [3]. Older children usually undergo resection of the coarctation and end-to-end anastomosis. Previously published work shows the advantages of polydioxanone (PDS), an absorbable monofilament suture, over polypropylene (Prolene), a nonabsorbable monofilament suture, in growing anastomoses [l, 2, 41. These studies demonstrated that PDS allows the vascular anastomoses to grow. Since 1983, we have used PDS suture in a variety of cardiovascular procedures [4]. However, some concerns have been expressed regarding aneurysm formation at the vascular anastomotic site when absorbable sutures are used [5]. This report describes the results in 15 consecutive patients who had resection of CoA and end-to-end anastomosis using PDS absorbable suture.
tomosis using PDS monofilament absorbable suture at The Milton S. Hershey Medical Center. Seven patients were male and 8 were female. Their weight at operation ranged from 5 to 26.9 kg (mean 15.4 kg). Preoperative cardiac catheterization in 13 patients
Patients and Methods
Study Population Between March 1983 and June 1989, 15 patients aged 2.5 months to 9.2 years (mean, 3.7 years) had a surgical repair of CoA consisting of CoA resection and end-to-end anasAccepted for publication Oct 30, 1990. Address reprint requests to Dr Myers, Division of Cardiothoracic Surgery, College of Medicine, The Milton S . Hershey Medical Center, The Pennsylvania State University, PO Box 850, Hershey, PA 17033.
0 1991 by The Society of Thoracic Surgeons
Table 1. Preoperative Data Weight
Age at Operation
Sex
0%)
(Y)
7 8
F F F F F M M M
16.6 14.0 14.3 18.5 5.5 15.0 8.7 30.0
9
M
10.5
10 11 12 13 14 15
M M
5.0 19.5 13.0 25.0 15.7 26.9
6.1 2.3 3.0 4.6 0.7 3.8 1.0 7.3 1.4 0.2 5.2 1.8 7.8 4.2 9.2
15.1 2.1
4.9 0.8
Patient No.
1 2 3 4 5 6
F M F F
Mean SEM SEM
=
Catheterization Gradient (mm Hg)
20
... 70 50 35 35 45 50 50
... ... 30 30 40 50 42.7 3.6
standard error of the mean.
0003-4975/91/$3.50
414
ARENAS ET AL COARCTATION OF THE AORTA
showed CoA gradients that ranged from 30 to 70 mm Hg (mean, 43 mm Hg). Mean age at catheterization was 3.6 years. Associated cardiac anomalies were ventricular septal defect in 3 patients, patent ductus arteriosus in 1 patient, and bicuspid aortic valve in 6 patients. One patient had patent ductus arteriosus ligation before CoA repair (Table 1).
Operative Technique Through a left fourth intercostal space thoracotomy, the entire aorta from the aortic arch to the diaphragm was mobilized. The patent ductus arteriosus or ligamentum arteriosum was ligated before excision of the CoA segment. An end-to-end anastomosis was performed with continuous PDS sutures on the posterior aspect of the aorta and interrupted PDS sutures on its anterior aspect. The aortic cross-clamp time ranged from 18 to 50 minutes (mean, 34 minutes).
Postoperative Management A right radial artery catheter was used to monitor blood pressure continuously. Sodium nitroprusside and intravenous propranolol or esmolol were used to control systemic hypertension in the immediate postoperative period to maintain peak systolic blood pressure at between 100 and 110 mm Hg. If hypertension persisted, regimens of oral captopril or propranolol or both were begun on the day after operation. Urine output was measured, blood chemistry tests for renal function were done, and stool was tested postoperatively for occult blood.
Intermediate-Term Evalua tion Thirteen patients returned to the pediatric cardiology clinic for routine postoperative evaluation. Two patients did not show up for their follow-up appointments. They were both well, as could be determined by telephone assessment. Follow-up ranged from 11 to 49 months (mean, 23 months) postoperatively. Electrocardiograms, chest radiographs, and routine physical examination including blood pressure measurements were obtained in all patients. Complete two-dimensional, pulsed-wave Doppler and color flow mapping echocardiography was performed successfully in 12 of the 13 patients using a Vingmed CFM 500 (Interspec, Inc, Ambler, PA) ultrasound system. Imaging and Doppler echocardiography were performed with 5.0- and 3.0-MHz phased array transducers. One patient could not be adequately sedated for noninvasive testing. Chloral hydrate sedation (60 to 100 mg/kg orally) was administered to the patients less than 3 years of age who were unable to cooperate. The aortic arch and the site of repair were imaged from the suprasternal notch to evaluate for residual CoA or anastomotic aneurysm. Ascending and descending aortic velocities were measured with high pulse repetition frequency pulsed-wave and continuous-wave Doppler echocardiography. Successful magnetic resonance imaging of the aortic arch was completed in 11 of the 13 patients, using a
Ann Thorac Surg 1991;51:41>7
Siemens Magnetom 1.O-Telsa scanner (Siemens Medical Systems, Inc, Islan, NJ). Chloral hydrate sedation was administered to uncooperative patients less than 6 years of age. Parental permission was obtained for the magnetic resonance imaging scan. One patient could not be adequately sedated and 1 patient did not show up for his appointment at the magnetic resonance imaging facility.
Results Clinical Status On the first postoperative day, 6 patients had serious hypertension, which was treated with sodium nitroprusside and propranolol to lower the systolic arterial blood pressure to between 100 and 110 mm Hg. Subsequently, antihypertensive medication was required in 6 patients, 3 patients received captopril for 2 to 4 weeks, and 3 patients received p-blockers for 2 to 4 weeks. In all but 1 patient, antihypertensive medication was discontinued within 1 month postoperatively. This patient no longer required antihypertensive medication at 2 months postoperatively. Six months postoperatively, neither systolic nor diastolic hypertension was present in any patient. Postoperative urine output and renal function tests were normal in all patients. Finally, neither paraplegia nor symptoms of intestinal ischemia occurred in any patient. At the most recent examination, all patients were clinically well, had no cardiovascular symptoms, and were no longer taking any medications. Cardiac murmurs were audible at follow-up examination in the 3 patients with restrictive ventricular septal defects, in 2 patients with mitral valve prolapse and mild regurgitation, and in 6 patients with bicuspid aortic valves. All patients had normal peripheral artery pulses. Chest radiographs showed normal cardiac dimensions except for mild cardiomegaly in 1 child with a moderate ventricular septal defect. Eight of 13 patients had normal echocardiographic results; chest radiographs showed biventricular hypertrophy in the patient with a ventricular septal defect who had cardiomegaly. Right ventricular hypertrophy voltage criteria were present in 2 patients without residual CoA or associated aortic stenosis. One patient with mitral valve prolapse and mild mitral insufficiency had borderline left ventricular hypertrophy. One patient with a bicuspid aortic valve and mild aortic stenosis showed left-axis deviation and complete right bundle-branch block postoperatively.
Noninvasive Evaluation Two-dimensional echocardiography did not suggest anastomotic aneurysm formation in any patient, and no residual CoA was detected in any patient after end-to-end anastomosis with PDS. Three patients showed mild narrowing at the anastomotic site compared with the dimensions of the ascending and descending thoracic aorta. Bicuspid aortic valves were noted in 6 of the 12 patients studied. Mitral valve prolapse was detected in 2 patients and restrictive perimembranous ventricular septal defects in 3 patients.
Ann Thorac Surg 1991;51:413-7
ARENAS ET AL COARCTATION OF THE AORTA
415
Fig 1. (A) Two-dimensional echocardiogram and color flow mapping of the aortic arch from the suprasternal notch (patient 1). Blue indicates laminar blood flow away from the transducer. Black arrows indicate level of end-to-end anastornosis. (AAo = ascending aorta; DAo = descending aorta; cr = cranial; 1 = left; p = posterior; r = right pulmonay artery.) ( B ) Magnetic resonance image (sagittal view) of the aortic arch (patient 1 ) .
Fig 2. (A) Two-dimensional echocardiogram and color flow mapping of the aortic arch from the suprasternal notch (patient 5). Blue indicates laminar blood flow away from the transducer. Black arrows indicate level of end-to-end anastomosis. (AAo = ascending aorta; DAo = descending aorta; cr = cranial; 1 = left; p =posterior; r = right pulmona y artery.) (B)Magnetic resonance image (sagittal view) of the aortic arch (patient 5).
Doppler echocardiographic evaluation of the ascending and descending aortic velocities defined the degree of associated aortic valve stenosis or residual aortic arch
gradient using the modified Bernoulli equation [ 6 ] . Peak instantaneous aortic valve gradients ranged from 0 to 27 mm Hg (mean, 12 mm Hg) and peak instantaneous aortic
416
ARENAS ET AL COARCTATION OF THE AORTA
Ann Thorac Surg 1991;51:41%7
Table 2. Follow-Up Data Blood Dopp1er Follow- Arch Patient up Gradient No. (mo) (mm Hg) LVSF" 7 1 8 3 4 5 15 14 10 16 11 13 12
Mean
SEM a
49 40 31 27 27 26 22 14 13 12 12 11 11 25 3.12
9 0 9 16 0 10 17 5 13 0
0.43 0.42 0.38 0.50 0.58 0.50 0.43 0.46 0.47
...
0.46
10 17
...
8.75 2.34
... 0.39
to poststenotic dilatation from preoperative jet hemodynamics (Table 2).
Pres-
Other Defects
sure Other (mm Doppler Hg) AS AS
BAV BAV VSD, MVP BAV BAV
MR
...
...
... ...
VSD BAV
120/54 90150 90/50 104/60 90150 1101. . . 11470 10464 1001. . .
...
...
106/60
BAV, VSD
...
MVP
MR
95/60 102/. . . 104/58
0.468 0.021
Normal > 0.28.
AS = mild aortic stenosis; BAV = bicuspid aortic valve; LVSF = left ventricular shortening fraction; MR = mitral regurgitation; SEM = standard error of the mean; MVP = mitral valve prolapse; VSD = ventricular septa1 defect.
arch gradients were 10 mm Hg or less (mean, 5 mm Hg) in 9 patients. Numerous studies have documented that Doppler maximal instantaneous gradient determinations significantly overestimate the peak-to-peak catheter gradient, especially with mild to moderate gradients [7, 81. Four patients had instantaneous aortic arch gradients greater than 10 mm Hg (range, 13 to 17 mm Hg). Thus, there was no serious residual CoA in this group of patients. Color mapping allows better visualization of the thoracic descending aorta than two-dimensional imaging alone. Often, the descending aorta distal to the left subclavian artery may be difficult to image, making the evaluation of aneurysm or recurrent CoA less reliable. Color flow mapping of the aortic arch showed virtually normal laminar flow in the descending aorta (Figs l A , 2A) with minimal turbulence. Thus, the anatomy of the repair and blood flow characteristics were essentially normal in all patients postoperatively. Magnetic resonance imaging studies provided excellent visualization of the entire aortic arch in all patients, but was particularly specific in defining the borders of the descending aorta in the area of the anastomosis (Figs l B , 2B). In this group of patients, no aneurysm or recurrent CoA was noted on magnetic resonance imaging, thereby confirming the data obtained with two-dimensional echocardiography and color flow mapping. With this imaging technique, mild dilatation of the descending aorta distal to the suture line was noted in 5 patients and was attributed
Comment The use of absorbable suture material for vascular anastomoses allows growth of the vessel, which is necessary for a successful long-term result after surgical repair to prevent recoarctation in infants and children. A potential limitation of end-to-end repair with nonabsorbable suture is that it may limit normal growth at the anastomotic site and lead to recoarctation. The use of noninvasive magnetic resonance imaging and two-dimensional color Doppler echocardiography allows the evaluation of hemodynamics and anatomical repairs and provides a reliable method by which to gain the information necessary for the postoperative evaluation of these patients. Our previous experiments in a growing porcine model demonstrated that the use of PDS for vascular anastomoses provides a good anatomical repair, normal growth at the anastomotic site, and normal integrity during burst testing [l, 21. Nevertheless, questions have been raised regarding the risk of aneurysm formation at the anastomotic site when using absorbable PDS [5]. Our prior experiences with animal models and our current experiences with children using PDS to repair CoA indicate good anatomical repair, good integrity of the anastomotic site, and physiological laminar blood flow characteristics, as well as adequate arterial growth and absence of recoarctation for as long as 49 months postoperatively. These results indicate that PDS is an acceptable material for repair of CoA in infancy and childhood and should continue to be used for the repair of vascular anastomoses in other forms of congenital heart disease. Although a longer follow-up period, including periodical noninvasive assessments, will be required to determine the long-term integrity of aortic anastomoses with absorbable suture, the use of PDS absorbable suture has been shown to be safe and reliable in our clinical and experimental experience.
References 1. Myers JL, Pae WE Jr, Waldhausen JA, Pierce WS. Vascular anastomoses in growing vessels: comparison of absorbable polydioxanone and nonabsorbable polypropylene monofilament suture materials. Surg Forum 1981;32:339-41. 2. Myers JL, Waldhausen JA, Pae WE Jr, Abt AB, Prophet GA, Pierce WS. Vascular anastomoses in growing vessels. The use of absorbable sutures. Ann Thorac Surg 1982;34:529-37. 3. Waldhausen JA, Whitman V, Werner JC, Pierce WS. Surgical intervention in infants with coarctation of the aorta. J Thorac Cardiovasc Surg 1981;81:323-5. 4. Myers JL, Campbell DB, Waldhausen JA. The use of absorbable monofilament polydioxanone suture in pediatric cardiovascular operations. J Thorac Cardiovasc Surg 1986;92:771-5. 5. Van Rijk-Zwikker GL. The effect of polydioxanone and
Ann Thorac Surg 1991;51:41>7
Prolene on circular aortic sutures under tension. Ned Tijdschr Geneeskd 1986;130:801-2. 6. Hatle L, Brubakk A, Tromsdal A, Angelsen B. Non-invasive assessment of pressure drop in mitral stenosis by Doppler ultrasound. Br Heart J 1978;40:13140. 7. Currie F'J, Hagler DJ, Seward JB, et al. Instantaneous pressure
ARENAS ET AL COARCTATION OF THE AORTA
417
gradient: a simultaneous Doppler and dual catheter correlative study. J Am Coll Cardiol 1986;7800-6. 8. Smith MD, Dawson PL, Elion JL, et al. Systematic correlation of continuous wave Doppler and hemodynamic measurements in patients with aortic stenosis. Am Heart J 1986;lll: 245-52.
Notice From the American Board of Thoracic Surgery Regarding Trainees and Candidates for Certification Who Are Called to Military Service Related to the Persian Gulf Conflict The Board appreciates the concern of those who have received emergency call to military service. They may be assured that the Board will exercise the same sympathetic consideration as was given to candidates, in recognition of their special contribution to their country, during the Korean and Viet Nam conflicts with regard to dead-
lines, applications, examinations, and interruption of training.
Harvey W. Bender, Jr, M D Chairman The American Board of Thoracic Surgery