Coarctation of the abdominal aorta

Coarctation of the abdominal aorta J o n R. C o h e n , M_D, and Elisa B i r n b a u m , MD, New Hyde Park, N.Y. Coarctation of the abdominal aorta remains a surgically treatable cause o f hypertension in children and young adults. Average age of the patients is 21 years at the time o f diagnosis and a second peak in the fourth to fifth decade. I f left untreated, most patients die as a result of complications from untreated hypertension by the age of 35 years. Aortography remains the diagnostic test of choice with associated visceral and renal artery stenoses occurring in 26% of cases. O f the 146 cases reported, 109 had surgical treatment with an operative mortality rate of 6.9%. O f those patients having surgery 96% were normotensive or were easily controlled postoperatively with antihypertensive medications. Because claudication is a minor problem in most cases, surgical correction of the hypertension by hepatorenal or splenic-renal bypasses may be the preferred initial surgical treatment in patients without significant visceral artery involvement or severe symptomatic lower extremity ischemia. (J VAsc SuRG 1988;8:160-4.)

Coarctation o f the abdominal aorta, first described by Quain 1 in 1947, is a well-documented cause o f correctable hypertension in children. T o date, 146 cases have been described in the English language literature o f this peculiar anatomic defect that usually involves the suprarenal aorta with or without renal artery involvement? -1° Untreated, the complications o f hypertension are progressive, with death usually occurring as a result o f cardiac failure or cerebral hemorrhage in the fourth decadeY Several different surgical procedures have since been described that have successfully alleviated the often uncontrollable hypertension in the affected children. Most surgical procedures involve a thoracoabdominal incision and bypass grafts with Dacron and saphenous vein grafts. In this article, we report the first case o f simultaneous hepatorenal and splenorenal bypasses without repair o f the aortic coarctation in a 17-year-old girl with abdominal coarctation, bilateral renal artery stenoses, and uncontrollable hypertension and review the English language literature o f abdominal aortic coarctations. CASE R E P O R T A 17-year-old white girl was seen by her pediatrician with the primary complaint of headache. She had no history of recent febrile episodes, congenital anomalies, neurofibromatosis or cafe-au-lait spots, claudication, or ruesenteric insufficiency. During physical examination diminished femoral pulses, an abdominal bruit, and blood From the Department of Surgery, Long Island Jewish Medical Center and State Universityof New York, Stony Brook. Reprint requests: Jon R. Cohen, MD, Department of Surgery, Long Island Jewish Medical Center, New Hyde Park, NY 11042. 160

pressure of 220/110 mm Hg were noted. Doppler pressures revealed an anlde-brachial index of 0.7 at both ankles. The electrocardiogram was consistent with left ventricular hypertrophy. Values of blood urea nitrogen, creatinine, and urinalysis were normal as were other laboratory values. Attempts at medical treatment of the hypertension were unsuccessful. The patient was admitted to file pediatric intensive care unit for intravenous nitroprusside therapy. An aortogram revealed an abdominal coarctation with a small, severely stenotic aorta from below the superior mesenteric artery to below the renal arteries. There were 95% stenoses of both renal arteries originating from the coarcted aorta and a 60% stenosis at the origin of the superior mesenteric artery. Extensive collateralization was seen between the branches of the superior and inferior mesenteric arteries. The celiac axis and its branches were normal as was the aorta below the renal arteries (Fig. 1). We elected to repair both renal arteries at the same time without repairing the abdominal coarctation via right hepatorenal bypass (renal artery to hepatic artery, end to side, respectively with reversed saphenous vein) and left splenorenal bypass (splenic artery to renal artery, end to end, without graft). This allowed correction of the hypertension without the use of prosthetic material and avoided the standard thoracoabdominal bypass. The patient was healthy, active, and normotensive with one antihypertensive medication 9 months after operation. COLLECTED DATA The term "coarctation" is used in the English language literature exclusively for the designation o f a congenital anomaly. Therefore after a review o f all cases o f aortic stenosis in the English language literature, this article includes only those patients reported to have aortic stenosis on a congenital basis. We identified 146 cases o f abdominal aortic coarcration and the analysis o f the diagnostic and thera-

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Big. 1. Coarctation of abdominal aorta. A, Black arrow indicates tight right renal artery stenosis, white arrow indicates large meandering mesenteric artery. B, Black arrows indicate coarcted abdominal aorta; black and white arrow indicates mild narrowing of superior mesenteric artery at its origin.

peutic problems of the dinical behavior of this lesion will be discussed on the basis of these data. CLINICAL PICTURE The clinical presentation depends on the anatomic site of the lesion. Those patients with lesions at or above the renal arteries initially have hypertension, whereas those with lesions below the renal arteries have claudication. Patients may complain of headaches, dyspnea, fatigue, or leg weakness. Occasionally a patient presents in congestive heart failure or after a cerebrovascular accident. Frequently a patient is asymptomatic but has abnormalities discovered during physical examination. Hypertension in the upper extremity, abdominal bruits, systolic or continuous bruits over the posterior thoracic and lumbar areas, and decreased pulses in the lower extremities are commonly noted. Peripheral perfusion pressures decrease during exercise and Doppler studies show a decrease in aortic inflow. 2 Cardiomegaly or other evidence of heart failure may be evident on plain chest x-ray films. Occasionally, notching of the lower ribs with the presence of an aortic knob is seen as well. Intravenous pyelograms are reportedly normal in one fourth of cases studied in this manner, a2Aortography is the standard test for confirming the diagnosis and is a requirement for operative planning. Patients have occasionally had a surgical procedure for a presumed thoracic coarctation and later been found to have an abdominal aortic coarctation on angiography. 3'~'~3'~4The site of the lesion is evaluated as are any anatomic abnormalities that might be encountered. Pressure gradients across the aortic stenosis have been recorded at approximately 65 mm Hg. 2 Measurements of renin have not been uniformly

analyzed in all patients with abdominal aortic coarctations. Several clinical studies have suggested a renal source of increased renin production and have shown lateralization of renin values with unilateral renal artery stenosis. 2,4 In patients with bilateral renal artery stenoses and suprarenal coarctation, the hypertension is predominantly maintained as a volume phenomenon without elevation of circulating renin. Scott et al.,ls with an animal model of abdominal aortic coarctation, found systemic hypertension and lateralization of renal vein renin ratios in those animals with interrenal coarctation and no hypertension or changes in renin ratios in those animals with infrarenal coarctation. This suggests a renal origin for the hypertension similar to that found in clinical experiences, is These authors also studied the effect of saralasin on the hypertensive animals and found that the blood pressure increased. This was unexpected since saralasin acts as a competitive inhibitor of angiotensin II and should cause a reduction in the hypertension if it is mediated by the renin-angiotensin system. Pierach and Katkov 12 measured renin before and after surgical correction of an abdominal aortic coarctation and showed that there was no change in the renin levels before and after bypass surgery. It is believed by other researchers that the kidneys mediate the hypertension through a mechanism other than the renin-angiotensin system. To date, there is no general consensus on the origin of hypertension in patients with abdominal aortic coarctation. The differential diagnosis of patients with these signs, symptoms, and arteriographic findings includes abdominal aortic coarctation and aortic stenosis on an acquired basis. Acquired aortic lesions mimicking aortic coarctation include aortic neurofibromatosis, 1~,~7Takayasu's aortitis, 12"18aortic tuber-

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CulOSiS, 19 and radiation aortitis. 2° A history of an early prodromal generalized systemic phase in a patient of Asian descent may help differentiate aortic coarctation from Takayasu's aortitis. A history of tuberculosis or radiation should alert the physician that the aortic lesion is most likely acquired as a result of one of these causes. Neurofibromatosis may be difficult to differentiate from aortic coarctation in the early phases; however, biopsy of the periaortic tissue at the time of surgery will establish this diagnosis.

INCIDENCE Coarctation of the abdominal aorta accounts for approximately 2% of all aortic stenoses. The average age at diagnosis is 20.7 years with a second peak in the fourth to fifth decade. The male:female ratio is approximately i to i (51% male, 49% female), which is in contrast to the 2 : 1 ratio in the more con~mon thoracic coarctations. Associated visceral and renal artery stenoses occur in many patients. The superior mesenteric artery, inferior mesenteric artery, or celiac axis is involved in 26% of the cases reviewed. Commonly, either the superior mesenteric or the inferior mesenteric artery is stenotic or hypoplastic, resulting in an increase in collateral blood flow through the meandering mesenteri c artery. Renovascular abnormalities have been described including multiple renal arteries, hypoplasia, and poststenotic aneurysms. Renal artery stenosis is found in 84% of patients and multiple renal arteries in approximately 70% of patients with abdominal aortic coarctations. Concurrent thoracic coarctations and cardiovascular abnormalities such as supravalvular aortic stenosis, 4 mitral valve insufficiency, pulmonary artery coarctation, and subclavian artery stenosis have also been reported in a few casesY

CLASSIFICATION Robicsek et al.6 proposed that the lesions be classifted on the basis of the anatomic location of the lesion: class I--infrarenal aortic coarctation, class II--suprarenal aortic coarctation, and class I I I - aortic coarctation with renal involvement. Hailer et al.a proposed a classification into four groups to aid in surgical decision making: group I--suprarenal aortic coarctation with renal artery stenosis, group II--infrarenal aortic coarctation with renal artery stenosis, group III--suprarenal aortic coarctation with normal renal arteries, and group IV--infrarenal aortic coarctation with normal renal arteries. Further subdivision can be made by grouping the lesions into diffusely hypoplastic or short segmental coarcta-

tions. 21 In our review of 146 patients, 49% of all lesions were interrenal (with short extensions above and below the renal arteries), 17% were suprarenal, 23% were infrarenal, and 11% were diffuse coarctations. ETIOLOGY The exact origin of abdominal aortic coarctation is unknown. The young age of most of the patients suggests that the malformation may be congenital. During fetal development, the truncus arteriosus ends in the aortic sac from which the paired aortic arch arteries arise. These arteries end in one of the paired dorsal aortas. The dorsal aortas fuse to become a single dorsal aorta just distal to the left subclavian artery during the first month of development. Errors in fusion of the dorsal aorta in utero would theoretically result in a coarctation as initially described by Maycock= in 1937. It has also been suggested that in utero infection (e.g., rubella) could cause vascular anomalies by interfering with cellular growth or by exerting a direct cidal effect during any part of this developmental phase. 23,2~ Atherosclerosis does not seem to be a factor in the origin of this disease. The atherosclerotic changes, when present, are believed to be a result of the hypertenslon caused by the coarctation and are generally fotmd proximal to the coarctanon. I2m PATHOLOGIC STUDIES Most surgical procedures performed for abdominal aortic coarctation have been bypasses and frequently no tissue specimen was histologically described in the literature. The external diameter of the aorta is often normal for the age of the child. 13 The most common pathologic tissue specimen has been an intact aorta with subintimal fibrosis and without inflammatory changes. Often the medial and adventitial layers are normal. 21,2s Fibrosis and intimal proliferation with an increase in elastic fibers and collagen in the media may" also be found. 26 SURGICAL INTERVENTION Before surgical intervention, the life expectancy associated with this condition was not greater than 30 to 40 years. Bjork and Intonti n reported on 14 patients in 1966 who did not have operative correction and in whom the average age at death was 30 years. Since 1952 there has been a significant increase in the number of surgically treated patients. Approximately 70% to 80% of surgically treated patients become norrnotensive or experience a decrease

Volume 8 Number 2 August 1988

m blood pressure to a level easily managed with antihypertensive medication. The operative mortality rate is estimated at 4% to 8% depending on the extent of arterial involvement. The most common surgical procedure is a bypass from the thoracic aorta to the distal abdominal aorta with a synthetic graft. Resection of the coarcted aorta with an interposition graft has been reported for short segments. Patch graft angioplasty of the narrowed aortic segment has also been reported for short segmental coarctations. Concurrent renal artery lesions have been corrected with synthetic or saphenous vein bypass grafts or by renal artery reimplantation into the normal aorta or graft. Because of their anatomic differences, the right and left renal arteries have been treated differently. Hallet et al.,3 Nennhaus 'et al.,2 and Bloor and Williams28 have all done sp!enorenal anastomoses for lesions in the left renal artery. Vaccaro et al.4 used the hypogastric artery to anastomose to the right renal artery. In several cases the renal artery could not be bypassed or bypass failed and nephrectomy was needed to control the hypertension. Of the 146 patients reviewed, including the case presented herein, 109 had operative treatment; there were 58 thoracoabdominal bypasses, 16 aortopiasties, 16 renal revascularizations or nephrectomies, and 19 miscellaneous procedures. In addition to these procedures, renal revascularization or nephrectomy was done in 60 cases. Superior mesenteric artery or celiac revascularization was done in 11 patients. The operative mortality rate in these 109 patients was 6.9%. Of the patients having operation, 96% were normotensive or easily controlled with antihypertensive medication. Only 9.4% of patients having operation had unsatisfactory results. Our patient had coarctation at the renal arteries with a short extension above and below the arteries, bilateral renal artery stenoses, and superior mesenteric artery stenosis. Right hepatorenal and left splenorenal bypasses were done without the standard thoracoabdominal bypass. No attempt at correction of the coarctation or superior mesenteric artery stenosis was deemed necessary as the patient had no lower extremity or mesenteric complaints. Our rationale for this approach is that the major threat to life in our patient and most others is the progression of the complications of hypertension. Claudication has been a minor problem in most patients because of the existence of long-standing collateral vessels and was not a complaint in our patient; no current evidence exists to suggest that the claudication is progressive in this subset of patients. In

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addition, this approach avoids the use of synthetic grafts in this young population. The last major advantage to this approach is that "no bridges have been burnt." If claudication or mesenteric insufficiency becomes a problem, then corrective surgery can still be performed by standard approaches. REFERENCES 1. Quain R. Partial contraction of the abdominal aorta. Trans Pathol Soc London 1848;1:244-5. 2. Graham LM, Zelenock GB, Erlandson EE, Coran AG, Lindenauer SM, Stanley JC. Abdominal aortic coarctarion and segmental hypoplasia. Surgery 1979:86:519-29. 3. Hallett JW, Brewster DC, Darling RC, O'Hara PJ. Coarcration of the abdominal aorta. Ann Surg 1980;191:430-7. 4. Vaccaro PS, Myers JC, Smead WL. Surgical correction of abdominal aortic coarctation and hypertension. J VAsc SURG 1986;3:643-8. 5. Case records of the Massachusetts General Hospital. N Engl J Med 1986:314:1304-11. 6. Robicsek F, Daugherty HK, Cook JW, Cafoncelli A. Coarctation of the abdominal aorta with stricture of the major vessels. Surgery 1980;87:545-8. 7. Stelzner M, Horsch S~ Beyer D. Abdominal and thoracic coarctation of the aorta with bilateral renal artery stenosis. Ann Vasc Surg 1986;1:486-8. 8. Svare J, Hansen JB, Brons J. Coarctation of the abdominal aorta. Acta Chir Scand 1980;502:104-10. 9. Stanley JC, Fry WJ. Pediatric renal artery occlusive disease and renovascular hypertension. Arch Surg 1981; ! 16:669-76. 10. Bergentz S-E, Bergqvist D, Ericsson BF, Esquivel CO. Coarcration of the abdominal aorta associated with renal hypertension. Vasa 1983:12:133-8. 11. Bjork VO, Intonti F. Coarctati0n of abdominal aorta with right renal artery stenosis. Ann Surg 1964;160:54-60. 12. Pierach C, Katkov H. Coarctation of the abdominal aorta. Vasc Surg 1972;6:159-66. 13. Riemenschneider TA~ Emmanouilides GC, Hirose F, Linde L. Coarctation of the abdominal aorta in children: report of three cases and review of the literature, Pediatrics 1969: 44: 716-26. 14. Bahnson HT, Cooley RN, Sloan RD. Coarctation of the aorta at unusual sites. Am Heart J 1949;38:905-13. 15. Scott HW, Dean RH, Boerth R, Sawyers JL, Meacham P, Fisher RD. Coarctafion of the abdominal aorta. Ann Surg 1979;189:746-57. 16. Greene JF, Fitzwater JE, Burgess J. Arterial lesions associated with neurofibromatosis. Am J Clin Pathol 1974;62:481-7. 17. Schurch W, Mcsserli FH, Genest J, et al. Arterial hypertension and neurofibromatosis: renal artery stenosis and coarctafion of abdominal aorta. Can Med J Assoc 1975; 113:879-85. 18. Lande A. Takayasu's arteritis and congenital coarctation of the descending thoracic and abdominal aorta: a critical review. Am J Roentgenol 1976;127:227-33. 19. Sen PK, Kinare SG, Kilkarni TP, Parulkar GB. Stenosing aortitis of unknown etiology. Surgery 1962;51:317-25. 20. Colquhoun J. Hypoplasia of the abdominal aorta following therapeutic irradiation in infancy. Radiology 1966;86: 454-6. 21. Ben-Shoshan M, Rossi NP, Komks ME. Coarctation of the abdominal aorta. Arch Pathol 1973;95:221-5.

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22. Maycock Wd'A. Congenital stenosis of the abdominal aorta. Am Heart J 1937;13:633-46. 23. Siassi B, Klyman G, Emmanouilides GC. Hypoplasia of the abdominal aorta associated with the rubella syndrome. Am J Dis Child 1970;120:4760-9. 24. Limbacher JP, Hill ME, Janicki PC. Hypoplasia of the abdominal aorta associated with rubella syndrome. South Med ] 1979;72:617-9. 25. Huang Tr, Wolma FJ, Tyson KR. Coarctation of the abdominal aorta. Am J Surg 1970;120:598-601.

26. Sproul G, Pinto J. Coarctation of the abdominal aorta. Arch Surg 1972;105:571-3. 27. Nennhaus HP, Jaxfd H, Huner JA. Surgical treatment of renovascular hypertension in children with a review of infradiaphragmatic arterial hypoplastic anomalies. J Thorac Cardiovasc Surg 1967;54:246-58. 28. Bloor K, Williams RT. Neurofibromatosis and coarctation of the abdominal aorta with renal artery involvement. Br J Surg I963;50:811-3.

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