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Left subclavian-aortic bypass grafting in primary isolated adult coarctation
Cardiovascular Surgery, Vol. 7, No. 3, pp. 351–354, 1999 1999 The International Society for Cardiovascular Surgery. Published by Elsevier Science Ltd All rights reserved. Printed in Great Britain 0967–2109/99 $20.00 ⫹ 0.00
PII: S0967-2109(98)00164-1
Left subclavian-aortic bypass grafting in primary isolated adult coarctation A. Elkerdany, A. Hassouna, T. Elsayegh, Sh. Azab and M. Bassiouni Department of Cardiovascular and Thoracic Surgery, Ain-Shams University Hospitals, Cairo, Egypt In the adult patient, bypassing the coarcted segment with a tube graft has been described, among others, as a method of repair in re-do cases and in high-risk patients. Since 1992, and owing to its simplicity, it has become our elected approach in all adult cases. Twenty-two patients (mean age 22.8 ⫾ 7.18 years) with isolated aortic coarctation distal to the left subclavian artery were primarily treated with left subclavian-lower descending thoracic aorta bypass using a Hemashield woven double velour graft. There was no hospital mortality nor major postoperative complications. The patients were followed-up for a mean period of 2.36 ⫾ 1.29 years (range 1–5 years). Systolic blood pressure as well as the pressure gradient across the coarcted segment dropped significantly from 181.82 ⫾ 15.7/65.7 ⫾ 13.3 mmHg to 124 ⫾ 13.63/7.41 ⫾ 6.49 mmHg (P ⫽ 0.009 and 0.001). Sixteen patients (72.6%) were recorded to be symptom-free and normotensive and seven patients (31.8%) did not show any residual pressure gradient when last seen. The postoperative systolic pressure correlated positively with its preoperative value (P ⫽ 0.017) as well as with patient age (P ⫽ 0.015). Partial correlation, however, suggested that advanced age upon surgery was the determinant factor responsible for residual postoperative systemic hypertension (P ⫽ 0.007). Besides being simple, the procedure is low-risk, permits a significant drop in pressure gradient and improves systolic hypertension through an intermediate follow-up period. 1999 The International Society for Cardiovascular Surgery. Published by Elsevier Science Ltd. All rights reserved. Keywords: adult, blood vessel prosthesis, coarctation, follow-up studies, hypertension
Introduction Isolated aortic coarctation is classically repaired by resection and end-to-end anastomosis, interposition of a tube graft, subclavian flap or synthetic patch aortoplasty. In the adult patient, however, resection involves mobilization of a relatively immobile aorta with large collaterals adjacent to the coarcted segment, which carries the hazard of serious intraoperative [1] or postoperative [2] haemorrhage. It is advisable not to sacrifice the adult left subclavian artery for fear of limb ischaemia, and patch aortoplasty is associated with late aneurysm formation in as many as 20% of patients [3]. All these options necessitate the division of a number of intercostal
Correspondence to: Dr Ahmed Hassouna, PO Box 93, El Mukattam, 11571 Cairo, Egypt. E-mail: [email protected]
CARDIOVASCULAR SURGERY
APRIL 1999 VOL 7 NO 3
arteries and total cross-clamping of the aorta, which may lead to sacrificing the radicular artery, or more commonly, its inadequacy during aortic crossclamping results in the rare but serious hazard of paraplegia [4]. Since 1992, the authors’ policy has been to use a left subclavian-descending thoracic aorta bypass graft in all adult patients with primary aortic coarctation distal to the left subclavian artery. The purpose of this report is to evaluate the safety and efficacy of this procedure and provide intermediateterm follow-up results.
Methods Between January 1992 and January 1997, 22 consecutive adult patients were referred to our department for surgical treatment of primary isolated coarctation of the aorta distal to the left subclavian 351
Left subclavian-aortic bypass grafting in primary isolated adult coarctation: A. Elkerdany et al.
artery. As shown in Table 1, they were 16 males (72.6%) and six females, whose mean age was 22.8 ⫹ 7.18 years (range 16–47 years). All patients had critical systolic hypertension (181.82 ⫾ 15.7 mmHg; range: 160–220 mmHg) despite the regular use of between one and three oral antihypertensives. The diagnosis of isolated aortic coarctation was confirmed by echocardiography in all cases. The pressure gradient across the coarcted segment varied between 50 and 110 mmHg with a mean value of 65.7 ⫾ 13.3 mmHg. Two patients (patient no. 7 and no. 12) were subjected, in addition, to aortography during an unsuccessful attempt at balloon dilatation. The descending thoracic aorta was approached via a left posterolateral thoracotomy, through the fourth intercostal space. The coarcted segment was bypassed by the use of a Hemashield woven double velour tube graft in all cases. The proximal end of the graft was first sutured to the base of left subclavian artery with a 5/0 prolene overrunning suture and haemostasis was checked-out. The distal end was then implanted, by a similar suturing technique, onto the partially-clamped lower descending thoracic aorta away from the stenosed segment and its following dilated part. Postoperative hypertension was controlled with sodium nitroprusside infusion during the first 24 hours. The drug was then tailored off and replaced with an oral antihypertensive regimen that was later
adjusted by the referring physician. A yearly clinical and echocardiographical follow-up was done for all patients. Statistical analysis Data were analysed with SPSS software for windows (release 5.0.2. 1993). Differences between categorical variables were assessed by Fisher’s exact test or by chi-square contingency analysis. Continuous variables were expressed as means ( ⫾ s.d.) and were analysed with the paired Student’s t-test, the unpaired Student’s t-test, Spearman’s correlation and partial correlation tests. A P-value of ⬍ 0.5 was considered significant.
Results No hospital mortality nor major postoperative complications were recorded, and all patients left the hospital within the first postoperative fortnight. The size of the implanted tube graft varied between 12 and 24 mm, with a mean diameter of 19.82 ⫾ 2.75 mm. Although the tube size correlated positively with the patient’s age (P ⫽ 0.007), it did not show a statistically significant relation with the patient’s gender. Patients were followed up for a period that ranged between 1–5 years, with a mean duration of 2.36 ⫾
Table 1 Summary of selected variables Patient no.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 Mean ⫾ s.d.
Sex
M M M F M F M M M M F M M F M M F M M M M F
Age (years)
22 34 22 20 18 21 16 20 24 28 29 16 47 24 21 17 18 26 28 24 31 18 22.8 7.2
Systolic blood pressure (mmHg)
Systolic pressure gradient (mmHg)
Preoperative
Postoperative
Preoperative
Postoperative
160 200 180 170 180 165 190 170 200 220 190 180 200 180 160 170 190 180 190 170 195 160 181.8 15.7
110 140 125 125 115 120 120 115 145 135 110 110 160 125 118 110 115 145 130 110 120 125 124 13.6
50 60 110 70 55 75 70 50 70 60 50 55 70 75 60 70 60 60 55 70 80 70 65.7 13.3
5 0 15 16 0 10 12 4 7 11 10 0 8 12 0 10 5 0 0 0 18 20 7.4 6.5
Graft size (mm)
Follow-up (years)
20 22 22 20 18 22 16 20 22 22 22 18 24 20 22 18 20 22 18 20 16 12 19.8 2.7
1 2* 2 1 2 1 1 3 3* 4* 2 2 1* 3 3 2 3 5* 5* 4 1 1 2.36 1.29
*Patients on medical antihypertensive therapy postoperatively
352
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Left subclavian-aortic bypass grafting in primary isolated adult coarctation: A. Elkerdany et al.
1.29 years. As shown in Table 1, there was a statistically significant drop in the pressure gradient across the coarcted segment, which ranged from 40 to 85 mmHg, with a mean value of 52.41 ⫾ 10.14 mmHg (P ⫽ 0.001). Seven patients (31.8%) did not have any residual gradient; these were all males. The others (nine males and six females) kept a residual gradient that varied from 5 to 20 mmHg (10.86 ⫾ 4.8 mmHg). At their last follow-up visit, 16 patients (72.6%) were asymptomatic and normotensive (117.06 ⫾ 6 mmHg). The other six patients (27.4%) had their systolic blood pressure (142.5 ⫾ 10.37 mmHg; range 130–160 mmHg) controlled by a combination of a diuretic and a -blocking agent (four patients), or an angiotensin-converting enzyme inhibitor (two patients). Their mean age during surgery (31.16 ⫾ 8.4 years) was significantly higher than that of the other 16 patients (21.06 ⫾ 4.3 years; P ⫽ 0.003). Possible predictors of residual systemic hypertension were analysed. The patients’ sex, preoperative pressure gradient across the coarcted segment, graft size and duration of follow-up were all statistically irrelevant. On the other hand, the mean postoperative systolic blood pressure of the whole group of patients correlated positively with its preoperative value (P ⫽ 0.017) as well as with the patients’ age at the time of surgery (P ⫽ 0.015). Figure 1 shows that while taking into consideration its preoperative value, the postoperative systolic blood pressure maintained its positive correlation with the age of the patient (partial correlation: P ⫽ 0.007).
Discussion Bypassing the coarcted aortic segment was described between the ascending and descending thoracic aorta, as early as 1960 [5]. Later on, Weldon and collaborators advocated the use of the aortic arch or the subclavian artery as the feeding vessel [6]. The diversity of clinical situations urged the creation of various bypass graft designs and approaches [7, 8] that were mainly indicated in re-do cases with extensive adhesions and poor collaterals across the coarcted segment [7, 9–11]. Bypass grafts were adopted primarily whenever cross-clamping of the aorta was considered to be unsafe in patients with mild coarctation [2], as well as in those patients with long [7, 12] or complex forms of aortic coarctation at or proximal to the junction of the arch and the descending thoracic aorta [13]. Their application has varied from 0–14% in 3 large series that included infants, children and young adults [2, 14, 15], to 42.3% in a strictly adult series [12]. The surgeon’s preference seems to be a major factor in choosing this approach [12], because in two other adult series, bypass grafts were never used [1, 16]. The most commonly used bypass design was CARDIOVASCULAR SURGERY
APRIL 1999 VOL 7 NO 3
proximal subclavian artery or distal transverse arch to distal descending thoracic aorta, performed through left thoracotomy [2, 6, 12, 13]. The authors have adopted the shortest and simplest bypass design in all our adult patients with isolated coarctation distal to the left subclavian artery. The procedure involves minimal dissection, if any, and the thoracic aorta is only partially cross-clamped. The collateral vessels are all preserved and the anastomosis is always tension-free and quite easy to perform. In concordance with other series [2, 12–15], our morbidity figures were quite low, with no hospital mortality nor spinal cord complications. The procedure was significantly effective in lowering the pressure gradient across the coarcted segment (P ⫽ 0.001) with a persisting trivial to mild gradient ( ⬍ 20 mmHg) in only two-thirds of the patients. Echocardiographic follow-up failed to demonstrate the previously reported true [17] or false [13] aneurysm formation at the site of anastomosis in any of our patients. The effect of coarctation repair on the adult systemic hypertension is a subject of debate. It is generally accepted that the risk of persistent hypertension increases with advancing age [1, 2, 14, 18]; its incidence varied from as many as 50% of patients [1, 18] to only 12% in a more recent adult series [12]. This lower incidence, as well as that reported here (27.4%), may reflect in part the effectiveness of actual antihypertensive drugs. Nevertheless, this study supports the finding that the mean age of patients whose blood pressure measurements normalize [1] or become medically controlled [12] after surgery is lower than that for patients who remained hypertensive; though age ranges overlap. In contradistinction to others [1], Lawrie and collaborators showed that the incidence of residual hypertension also correlated positively with the degree of preoperative systolic hypertension [18]. In our study, both advanced age (P ⫽ 0.015) and higher preoperative systolic hypertension (P ⫽ 0.017) correlated positively with the magnitude of postoperative systolic hypertension. Partial correlation, however, indicated that the patients’ age was the determinant factor (P ⫽ 0.007) responsible for residual hypertension after surgery. In conclusion, the presence of coarctation is an indication for surgery as systemic hypertension tends to persist with advancement of age. Although surgery should not be delayed, cases discovered in their second or third decades can still enjoy a normal postoperative systolic blood pressure. In this setting, simple tube bypass graft appears to be a safe and effective alternative to classical coarctectomy procedures.
Acknowledgements The authors would like to acknowledge Dr Hemmat Allam for her effort in revising this manuscript. 353
Left subclavian-aortic bypass grafting in primary isolated adult coarctation: A. Elkerdany et al.
Figure 1 Correlation between the patient’s age at the time of surgery and systolic blood pressure at intermediate-term follow-up (2.36 ⫾ 1.29 years). Preoperative systolic blood pressure (mm Hg) 쐌 220, 䊏 200, 䉬 195, 왖 190, ⴰ 180, 䊐 170, 䉫 165, 왕 160, - - - least square linear regression line.
References 1. Westaby, S., Parnell, B. and Pridie, R. B., Coarctation of the aorta in adults. Clinical presentation and results of surgery. Journal of Cardiovascular Surgery, 1987, 28, 124–127. 2. Behl, P. R., Sante, P. and Blesovsky, A., Isolated coarctation of the aorta: surgical treatment and late results. Eighteen years experience. Journal of Cardiovascular Surgery, 1988, 29, 509–517. 3. Aebert, H., Laas, J., Bednarski, P. et al., High incidence of aneurysm formation following patch plasty repair of coarctation. European Journal of Cardiothoracic Surgery, 1993, 7, 200–204. 4. Brewer, L. A., Fosburg, R. G., Mulder, G. A. and Vreska, J. J., Spinal cord complications following surgery for coarctation of the aorta. A study for 66 cases. Journal of Thoracic and Cardiovascular Surgery, 1972, 64, 368–381. 5. Shumacker, H. B., King, H., Nahrwold, D. L. and Waldhausen, J. A., Coarctation of the aorta. Current Problems in Surgery, Chicago year book, February 1968, 1–64. 6. Weldon, C. S., Hartmann, A. F. Jr, Steinhoff, N. G. and Morissey, J. D., A simple safe and rapid technique for the management of recurrent coarctation of the aorta. Annals of Thoracic Surgery, 1973, 15, 510–519. 7. Edie, R. N., Janani, J., Attai, L. A. et al., Bypass grafts for recurrent or complex coarctation of the aorta. Annals of Thoracic Surgery, 1975, 20, 558–566. 8. Connery, C. P., DeWeese, J. A., Eisenberg, B. K. and Moss, A. J., Treatment of aortic coarctation by axillofemoral bypass grafting in the high-risk patient. Annals of Thoracic Surgery, 1991, 52, 1281–1284. 9. Jacob, T., Cobanoglu, A. and Starr, A., Late results of ascending aorta-descending aorta bypass grafts for recurrent coarctation of aorta. Journal of Thoracic and Cardiovascular Surgery, 1988, 95, 782–787.
354
10. Sweeny, M. S., Walker, W. E., Duncan, J. M. et al., Reoperation for aortic coarctation: techniques, results and indications for various approaches. Annals of Thoracic Surgery, 1985, 40, 46–49. 11. Knyshov, G. V., Sitar, L. L., Glagola, M. D. and Atamanyuk, M. Y., Aortic aneurysms at the site of repair of coarctation of the aorta: a review of 48 patients. Annals of Thoracic Surgery, 1996, 61(3), 935–939. 12. Wells, W. J., Prendergast, T. W., Berdjis, F. et al., Repair of coarctation of the aorta in adults: the fate of systolic hypertension. Annals of Thoracic Surgery, 1996, 61, 1168–1171. 13. Grinda, J. M., Mace, L., Dervanian, P. et al., Bypass graft for complex forms of isthmic aortic coarctation in adults. Annals of Thoracic Surgery, 1995, 60(5), 1299–1302. 14. Clarkson, P. M., Nicholson, M. R., Barrat-Boyes, B. G. et al., Results after repair of coarctation of the aorta beyond infancy. A 10- to 28-year follow-up with particular reference to late systolic hypertension. American Journal of Cardiology, 1983, 51, 1481–1488. 15. Palatianos, G. M., Kaiser, G. A., Thurer, R. J. and Garcia, O., Changing trends in the surgical treatment of coarctation of the aorta. Annals of Thoracic Surgery, 1985, 40(1), 41–45. 16. Heger, M., Gabriel, H., Koller-Strametz, J. et al., Aortic coarctation: long-term follow-up in adults. Zeitschrift fur Kardiologie, 1997, 86, 50–55. 17. Fujita, T., Fukushima, N., Taketani, S. et al., Late true aneurysm after bypass grafting for long aortic coarctation. Annals of Thoracic Surgery, 1996, 62, 1511–1513. 18. Lawrie, G. M., De Bakey, M. E., Morris, G. C. Jr et al., Late repair of coarctation of the descending thoracic aorta in 190 patients. Archives of Surgery, 1981, 116, 1557–1560. Paper accepted 22 November 1998
CARDIOVASCULAR SURGERY
APRIL 1999 VOL 7 NO 3
PII: S0967-2109(98)00164-1
Left subclavian-aortic bypass grafting in primary isolated adult coarctation A. Elkerdany, A. Hassouna, T. Elsayegh, Sh. Azab and M. Bassiouni Department of Cardiovascular and Thoracic Surgery, Ain-Shams University Hospitals, Cairo, Egypt In the adult patient, bypassing the coarcted segment with a tube graft has been described, among others, as a method of repair in re-do cases and in high-risk patients. Since 1992, and owing to its simplicity, it has become our elected approach in all adult cases. Twenty-two patients (mean age 22.8 ⫾ 7.18 years) with isolated aortic coarctation distal to the left subclavian artery were primarily treated with left subclavian-lower descending thoracic aorta bypass using a Hemashield woven double velour graft. There was no hospital mortality nor major postoperative complications. The patients were followed-up for a mean period of 2.36 ⫾ 1.29 years (range 1–5 years). Systolic blood pressure as well as the pressure gradient across the coarcted segment dropped significantly from 181.82 ⫾ 15.7/65.7 ⫾ 13.3 mmHg to 124 ⫾ 13.63/7.41 ⫾ 6.49 mmHg (P ⫽ 0.009 and 0.001). Sixteen patients (72.6%) were recorded to be symptom-free and normotensive and seven patients (31.8%) did not show any residual pressure gradient when last seen. The postoperative systolic pressure correlated positively with its preoperative value (P ⫽ 0.017) as well as with patient age (P ⫽ 0.015). Partial correlation, however, suggested that advanced age upon surgery was the determinant factor responsible for residual postoperative systemic hypertension (P ⫽ 0.007). Besides being simple, the procedure is low-risk, permits a significant drop in pressure gradient and improves systolic hypertension through an intermediate follow-up period. 1999 The International Society for Cardiovascular Surgery. Published by Elsevier Science Ltd. All rights reserved. Keywords: adult, blood vessel prosthesis, coarctation, follow-up studies, hypertension
Introduction Isolated aortic coarctation is classically repaired by resection and end-to-end anastomosis, interposition of a tube graft, subclavian flap or synthetic patch aortoplasty. In the adult patient, however, resection involves mobilization of a relatively immobile aorta with large collaterals adjacent to the coarcted segment, which carries the hazard of serious intraoperative [1] or postoperative [2] haemorrhage. It is advisable not to sacrifice the adult left subclavian artery for fear of limb ischaemia, and patch aortoplasty is associated with late aneurysm formation in as many as 20% of patients [3]. All these options necessitate the division of a number of intercostal
Correspondence to: Dr Ahmed Hassouna, PO Box 93, El Mukattam, 11571 Cairo, Egypt. E-mail: [email protected]
CARDIOVASCULAR SURGERY
APRIL 1999 VOL 7 NO 3
arteries and total cross-clamping of the aorta, which may lead to sacrificing the radicular artery, or more commonly, its inadequacy during aortic crossclamping results in the rare but serious hazard of paraplegia [4]. Since 1992, the authors’ policy has been to use a left subclavian-descending thoracic aorta bypass graft in all adult patients with primary aortic coarctation distal to the left subclavian artery. The purpose of this report is to evaluate the safety and efficacy of this procedure and provide intermediateterm follow-up results.
Methods Between January 1992 and January 1997, 22 consecutive adult patients were referred to our department for surgical treatment of primary isolated coarctation of the aorta distal to the left subclavian 351
Left subclavian-aortic bypass grafting in primary isolated adult coarctation: A. Elkerdany et al.
artery. As shown in Table 1, they were 16 males (72.6%) and six females, whose mean age was 22.8 ⫹ 7.18 years (range 16–47 years). All patients had critical systolic hypertension (181.82 ⫾ 15.7 mmHg; range: 160–220 mmHg) despite the regular use of between one and three oral antihypertensives. The diagnosis of isolated aortic coarctation was confirmed by echocardiography in all cases. The pressure gradient across the coarcted segment varied between 50 and 110 mmHg with a mean value of 65.7 ⫾ 13.3 mmHg. Two patients (patient no. 7 and no. 12) were subjected, in addition, to aortography during an unsuccessful attempt at balloon dilatation. The descending thoracic aorta was approached via a left posterolateral thoracotomy, through the fourth intercostal space. The coarcted segment was bypassed by the use of a Hemashield woven double velour tube graft in all cases. The proximal end of the graft was first sutured to the base of left subclavian artery with a 5/0 prolene overrunning suture and haemostasis was checked-out. The distal end was then implanted, by a similar suturing technique, onto the partially-clamped lower descending thoracic aorta away from the stenosed segment and its following dilated part. Postoperative hypertension was controlled with sodium nitroprusside infusion during the first 24 hours. The drug was then tailored off and replaced with an oral antihypertensive regimen that was later
adjusted by the referring physician. A yearly clinical and echocardiographical follow-up was done for all patients. Statistical analysis Data were analysed with SPSS software for windows (release 5.0.2. 1993). Differences between categorical variables were assessed by Fisher’s exact test or by chi-square contingency analysis. Continuous variables were expressed as means ( ⫾ s.d.) and were analysed with the paired Student’s t-test, the unpaired Student’s t-test, Spearman’s correlation and partial correlation tests. A P-value of ⬍ 0.5 was considered significant.
Results No hospital mortality nor major postoperative complications were recorded, and all patients left the hospital within the first postoperative fortnight. The size of the implanted tube graft varied between 12 and 24 mm, with a mean diameter of 19.82 ⫾ 2.75 mm. Although the tube size correlated positively with the patient’s age (P ⫽ 0.007), it did not show a statistically significant relation with the patient’s gender. Patients were followed up for a period that ranged between 1–5 years, with a mean duration of 2.36 ⫾
Table 1 Summary of selected variables Patient no.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 Mean ⫾ s.d.
Sex
M M M F M F M M M M F M M F M M F M M M M F
Age (years)
22 34 22 20 18 21 16 20 24 28 29 16 47 24 21 17 18 26 28 24 31 18 22.8 7.2
Systolic blood pressure (mmHg)
Systolic pressure gradient (mmHg)
Preoperative
Postoperative
Preoperative
Postoperative
160 200 180 170 180 165 190 170 200 220 190 180 200 180 160 170 190 180 190 170 195 160 181.8 15.7
110 140 125 125 115 120 120 115 145 135 110 110 160 125 118 110 115 145 130 110 120 125 124 13.6
50 60 110 70 55 75 70 50 70 60 50 55 70 75 60 70 60 60 55 70 80 70 65.7 13.3
5 0 15 16 0 10 12 4 7 11 10 0 8 12 0 10 5 0 0 0 18 20 7.4 6.5
Graft size (mm)
Follow-up (years)
20 22 22 20 18 22 16 20 22 22 22 18 24 20 22 18 20 22 18 20 16 12 19.8 2.7
1 2* 2 1 2 1 1 3 3* 4* 2 2 1* 3 3 2 3 5* 5* 4 1 1 2.36 1.29
*Patients on medical antihypertensive therapy postoperatively
352
CARDIOVASCULAR SURGERY
APRIL 1999 VOL 7 NO 3
Left subclavian-aortic bypass grafting in primary isolated adult coarctation: A. Elkerdany et al.
1.29 years. As shown in Table 1, there was a statistically significant drop in the pressure gradient across the coarcted segment, which ranged from 40 to 85 mmHg, with a mean value of 52.41 ⫾ 10.14 mmHg (P ⫽ 0.001). Seven patients (31.8%) did not have any residual gradient; these were all males. The others (nine males and six females) kept a residual gradient that varied from 5 to 20 mmHg (10.86 ⫾ 4.8 mmHg). At their last follow-up visit, 16 patients (72.6%) were asymptomatic and normotensive (117.06 ⫾ 6 mmHg). The other six patients (27.4%) had their systolic blood pressure (142.5 ⫾ 10.37 mmHg; range 130–160 mmHg) controlled by a combination of a diuretic and a -blocking agent (four patients), or an angiotensin-converting enzyme inhibitor (two patients). Their mean age during surgery (31.16 ⫾ 8.4 years) was significantly higher than that of the other 16 patients (21.06 ⫾ 4.3 years; P ⫽ 0.003). Possible predictors of residual systemic hypertension were analysed. The patients’ sex, preoperative pressure gradient across the coarcted segment, graft size and duration of follow-up were all statistically irrelevant. On the other hand, the mean postoperative systolic blood pressure of the whole group of patients correlated positively with its preoperative value (P ⫽ 0.017) as well as with the patients’ age at the time of surgery (P ⫽ 0.015). Figure 1 shows that while taking into consideration its preoperative value, the postoperative systolic blood pressure maintained its positive correlation with the age of the patient (partial correlation: P ⫽ 0.007).
Discussion Bypassing the coarcted aortic segment was described between the ascending and descending thoracic aorta, as early as 1960 [5]. Later on, Weldon and collaborators advocated the use of the aortic arch or the subclavian artery as the feeding vessel [6]. The diversity of clinical situations urged the creation of various bypass graft designs and approaches [7, 8] that were mainly indicated in re-do cases with extensive adhesions and poor collaterals across the coarcted segment [7, 9–11]. Bypass grafts were adopted primarily whenever cross-clamping of the aorta was considered to be unsafe in patients with mild coarctation [2], as well as in those patients with long [7, 12] or complex forms of aortic coarctation at or proximal to the junction of the arch and the descending thoracic aorta [13]. Their application has varied from 0–14% in 3 large series that included infants, children and young adults [2, 14, 15], to 42.3% in a strictly adult series [12]. The surgeon’s preference seems to be a major factor in choosing this approach [12], because in two other adult series, bypass grafts were never used [1, 16]. The most commonly used bypass design was CARDIOVASCULAR SURGERY
APRIL 1999 VOL 7 NO 3
proximal subclavian artery or distal transverse arch to distal descending thoracic aorta, performed through left thoracotomy [2, 6, 12, 13]. The authors have adopted the shortest and simplest bypass design in all our adult patients with isolated coarctation distal to the left subclavian artery. The procedure involves minimal dissection, if any, and the thoracic aorta is only partially cross-clamped. The collateral vessels are all preserved and the anastomosis is always tension-free and quite easy to perform. In concordance with other series [2, 12–15], our morbidity figures were quite low, with no hospital mortality nor spinal cord complications. The procedure was significantly effective in lowering the pressure gradient across the coarcted segment (P ⫽ 0.001) with a persisting trivial to mild gradient ( ⬍ 20 mmHg) in only two-thirds of the patients. Echocardiographic follow-up failed to demonstrate the previously reported true [17] or false [13] aneurysm formation at the site of anastomosis in any of our patients. The effect of coarctation repair on the adult systemic hypertension is a subject of debate. It is generally accepted that the risk of persistent hypertension increases with advancing age [1, 2, 14, 18]; its incidence varied from as many as 50% of patients [1, 18] to only 12% in a more recent adult series [12]. This lower incidence, as well as that reported here (27.4%), may reflect in part the effectiveness of actual antihypertensive drugs. Nevertheless, this study supports the finding that the mean age of patients whose blood pressure measurements normalize [1] or become medically controlled [12] after surgery is lower than that for patients who remained hypertensive; though age ranges overlap. In contradistinction to others [1], Lawrie and collaborators showed that the incidence of residual hypertension also correlated positively with the degree of preoperative systolic hypertension [18]. In our study, both advanced age (P ⫽ 0.015) and higher preoperative systolic hypertension (P ⫽ 0.017) correlated positively with the magnitude of postoperative systolic hypertension. Partial correlation, however, indicated that the patients’ age was the determinant factor (P ⫽ 0.007) responsible for residual hypertension after surgery. In conclusion, the presence of coarctation is an indication for surgery as systemic hypertension tends to persist with advancement of age. Although surgery should not be delayed, cases discovered in their second or third decades can still enjoy a normal postoperative systolic blood pressure. In this setting, simple tube bypass graft appears to be a safe and effective alternative to classical coarctectomy procedures.
Acknowledgements The authors would like to acknowledge Dr Hemmat Allam for her effort in revising this manuscript. 353
Left subclavian-aortic bypass grafting in primary isolated adult coarctation: A. Elkerdany et al.
Figure 1 Correlation between the patient’s age at the time of surgery and systolic blood pressure at intermediate-term follow-up (2.36 ⫾ 1.29 years). Preoperative systolic blood pressure (mm Hg) 쐌 220, 䊏 200, 䉬 195, 왖 190, ⴰ 180, 䊐 170, 䉫 165, 왕 160, - - - least square linear regression line.
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CARDIOVASCULAR SURGERY
APRIL 1999 VOL 7 NO 3