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J Thorac Cardiovasc Surg 1996;112:842-844
© 1996 Mosby, Inc.
BRIEF COMMUNICATIONS |
Zurich, Switzerland
Received for publication August 1, 1995 Accepted for publication Nov. 7, 1996. Address for reprints: Rolf Jenni, MD, MSEE, Division of Echocardiography, University Hospital Zurich, Rämistr. 100, 8091 Zurich, Switzerland.
Uncorrected coarctation of the aorta is associated with a substantially shortened life expectancy.
1 Corrective surgery for this condition was introduced in 1944. Resection and end-to-end anastomosis, extended end-to-end repair, prosthetic patch aortoplasty, prosthetic interposition grafts, subclavian flap aortoplasty, ascending aorta–descending aorta bypass, and balloon angioplasty have all been used in coarctation repair and have improved survival. 2,3 The increases in late morbidity and mortality after coarctation repair are primarily related to anastomotic site complications such as recoarctation or pseudoaneurysms and associated cardiovascular disease such as bicuspid aortic valve, mitral valve lesions, ventricular septal defect, and persistent systemic hypertension and its sequelae. An unusual case of peripheral arterial embolism caused by an anastomotic site complication is presented.
Case report
A 22-year-old man was admitted to the emergency department because of acute left leg ischemia. At the age of 1 month, he had undergone classic coarctation repair with resection and end-to-end anastomosis for a postductal aortic coarctation with no associated cardiovascular anomalies but untreatable congestive heart failure. Sixteen years later, coarctation recurred with a maximal systolic pressure gradient of 65 mm Hg, resulting from luminal narrowing with a minimal diameter of 7 mm. During the operation, diminished aortic wall quality was noted at the prior site of anastomosis and necessitated resection from the distal aortic arch to the intercostal arteries with interposition of a 20 mm USCI woven Dacron graft (Bard Inc., USCI Division, Billerica, Mass.). Continuous 3-0 and 4-0 Prolene sutures (Ethicon, Inc., Somerville, N.J.) were used. The postoperative recovery and follow-up were uneventful.
The patient was then free of symptoms for 6 years until 2 days before the current admission, when claudication of the left lower leg developed, followed by leg pain at rest. On admission, the left leg was cold, the left femoral pulse weak, and the left popliteal and peripheral pulses were absent. The right arm blood pressure was 135 mm Hg. The peripheral pressure was not measurable on the left side but was normal on the right side.
Findings on the electrocardiogram (sinus rhythm) and chest x-ray film were within normal limits. Digital subtraction angiography of the left leg showed thrombotic occlusion of the left external iliac artery and the left common femoral artery. The abdominal aorta was normal. In the region of the Dacron graft, an irregular lining of the graft with mild dilatation of the native aorta distal to the graft was observed. Transesophageal echocardiography demonstrated thrombotic apposition at the site of the distal anastomosis with adherence of two mobile thrombi but no evidence of dissection, aneurysm, or pseudoaneurysm formation. The transition between the graft and the descending thoracic aorta was unremarkable. No significant gradient was measurable at the prior coarctation site. Coagulation studies (including functional antithrombin III, protein C, and protein S levels) were within the normal range.
Emergency embolectomy was performed. During the operation, several dark red emboli were removed, the largest being 22 by 11 mm. The histologic characteristics were consistent with some older thrombi, with predominantly fresh appositional thrombus material. The postoperative course was uneventful, and signs of claudication resolved completely. The peripheral pulses are now palpable. The patient was started on a regimen of oral anticoagulants and acetylsalicylic acid. At 3 months' follow-up the patient was free of symptoms, and in the transesophageal echocardiogram the extension of the thrombotic material attached to the aortic wall had regressed substantially. Careful long-term follow-up every 6 months with transesophageal echocardiography is planned.
Discussion
Surgical correction of aortic coarctation has been successfully performed for more than four decades with better long-term results than those achieved with medical management. 1-3 However, survival is still shorter than expected. 3 Causes of premature death are coronary artery disease (37%), sudden death (13%), heart failure (9%), cerebrovascular accident (7%), ruptured aortic aneurysms (7%), perioperative death after a subsequent operation (7%), or other reasons (20%). 3 Up to 30% of patients have residual or recurrent coarctation after repair (necessitating reoperation in 3% to 5.4%), systemic hypertension, aneurysms, pseudoaneurysms, and other cardiovascular complications. 3 In our patient, restenosis was diagnosed 16 years after the initial classic end-to-end anastomosis. At the restenosis operation, an extended resection was necessary with the interposition of a Dacron graft because of the complex local site with extensive aortic wall changes. Six years after placement of this Dacron graft, the surprising embolic event occurred. Prosthetic interposition grafts have been used since 1960 in coarctation repair and are useful in selected cases, especially if the ends of the transected aorta cannot be approximated. Known long-term complications of Dacron aortic grafts include dilatation of the prosthetic grafts and false or, rarely, true aneurysms at the anastomotic site; such complications have also been described after coarctation repair. 4 Other complications, such as dehiscence of the proximal suture line of a Dacron tube graft resulting in a flap-valve effect and acute functional occlusion of the aorta, are rare. 5 A graft has a different compliance than the native aortic wall and thereby causes turbulence, which can induce aortic wall changes such as cystic medial necrosis and intimal damage. These changes may predispose to thrombus apposition. However, peripheral embolism after a Dacron aortic graft is rare and, if present, most commonly is the result of pseudoaneurysm formation.
Coagulation studies excluded an inherited disorder with disposition to arterial thrombosis. This case is therefore exceptional. The patient had no pseudoaneurysm formation and still had an embolic event as a result of local thrombus apposition. No similar case has ever been published. Careful life-long follow-up is necessary in patients after coarctation repair; follow-up examinations normally include assessment of hypertension at rest and during exercise and of possibly associated cardiovascular anomalies. The complication that occurred in this patient indicates that follow-up should also include assessment of the repair site excluding recoarctation, pseudoaneurysm or aneurysm formation, dilatation of an interposed graft, or local thrombus formation. The value of transesophageal echocardiography, computed tomography, and magnetic resonance imaging for the assessment of disease of the thoracic aorta have been widely demonstrated. However, they are also useful in the follow-up evaluation of coarctation repair for assessing pressure gradients, associated cardiac anomalies, and, as shown, the local repair site. Any embolic event in a patient after aortic repair makes careful assessment of the repair site compulsory.
Footnotes
From the Department of Surgery,a Division of Echocardiography,b Clinic for Cardio-Vascular Surgery,c and Department of Medical Radiology,d University Hospital Zurich, Switzerland. 
References
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