Combined Repair of Ascending Aortic Pseudoaneurysm and Abdominal Aortic Aneurysm in a Patient with Marfan Syndrome

Abstract

Pseudoaneurysms of the ascending aorta after the original inclusion/wrap technique of the Bentall procedure present a difficult surgical management problem and are associated with substantial morbidity and mortality. Patients with Marfan syndrome frequently develop aneurysms and dissections that involve multiple aortic segments. We present the case of a Marfan patient who successfully underwent repair of a giant ascending aortic pseudoaneurysm and concomitant repair of an abdominal aortic aneurysm. An aggressive surgical strategy followed by life-long cardiovascular monitoring is warranted in order to prolong the survival of these patients. (Tex Heart Inst J 2003;30:233–5)

Postoperative pseudoaneurysm formation at the coronary ostia or at the distal aortic suture line is a frequently reported sequela of the Bentall procedure for combined replacement of the ascending aorta and aortic valve. ¹ Reoperation, which is necessary to prevent catastrophic consequences, is itself associated with substantial rates of morbidity and mortality. ² Patients with Marfan syndrome frequently develop annulo-aortic ectasia and subsequent acute dissection involving multiple aortic segments. Graft replacement, even of multiple aortic segments, prolongs survival. We present the case of a patient with Marfan syndrome and a history of type A aortic dissection and aortic root replacement, in whom we successfully repaired a giant ascending aortic pseudoaneurysm and abdominal aortic aneurysm (AAA).

Case Report

A 37-year-old man with Marfan syndrome presented with chest pain and shortness of breath. Five years earlier, the patient had experienced an acute type A aortic dissection and had undergone replacement of the aortic root and ascending aorta by means of the classic Bentall procedure. Physical examination revealed a 3/6 aortic murmur in systole and a pulsating mid-abdominal mass. Transthoracic echocardiography revealed a well-functioning prosthetic valve in the aortic position, with minor posterior leakage. Magnetic resonance imaging (MRI) of the chest and abdomen demonstrated a giant pseudoaneurysm (12 cm) of the ascending aorta and a pool of blood surrounding the prosthetic graft (Fig. 1), together with an infrarenal AAA (7 cm) (Fig. 2). The patient was scheduled for urgent repair of both aneurysms.

Fig. 1 Preoperative magnetic resonance scan of the chest reveals the ascending aortic pseudoaneurysm.

L = left; R = right

Fig. 2 Preoperative magnetic resonance scan of the abdomen reveals the infrarenal abdominal aortic aneurysm.

L = left; R = right

At surgery, the right axillary artery and right femoral vein were cannulated, and cardiopulmonary bypass (CPB) was instituted. A repeat median sternotomy was performed. After minimal dissection, we cross-clamped the distal ascending aorta and began cooling the patient to 22°C. The pseudoaneurysm was incised and the composite graft was found to be partly disrupted, at the distal anastomosis site and at the right coronary ostium. There was also a small (approximately 1 cm) posterior disruption of the prosthetic valve at the aortic annulus. We decided to replace the composite graft completely. After graft removal, cardioplegia was administered through the coronary ostia, and the left ventricle was vented through the aortic annulus. A new composite graft, a 23-mm valved conduit (St. Jude Medical, Inc.; St. Paul, Minn), was inserted. The left coronary ostium was reimplanted through interposition of an 8-mm Dacron graft, while the right ostium was attached directly to the graft as a coronary button. The distal anastomosis to the circumferentially transected distal ascending aorta was performed in an open fashion during a short period (13 min) of circulatory arrest. Cardiopulmonary bypass was easily discontinued after the patient was rewarmed to 36°C. We then made a midline abdominal incision, resected the abdominal aneurysm, and inserted a bifurcated Dacron graft (16 ×8 mm) between the infrarenal aorta and the right common and left external iliac arteries. A separate segment of 8-mm Dacron graft restored the continuity between the left graft limb and the left internal iliac artery. The inferior mesenteric artery was reimplanted in the graft. The operation was concluded in the standard fashion.

Postoperative recovery was uneventful, apart from the patient's development of 2nd-degree atrioventricular block, which required the implantation of a pacemaker. The patient was discharged on postoperative day 8 in good condition, and he remains well 3 years later, without evidence of aneurysm formation elsewhere in the aorta (Fig. 3).

Fig. 3 Follow-up computerized tomographic scan shows the ascending aortic composite graft.

L = left; R = right

Discussion

Pseudoaneurysms of the ascending aorta occur in from 7% to 25% of patients in whom the original inclusion/wrap technique of the Bentall procedure has been applied. ¹ The main causes of pseudoaneurysm formation are 1) tension on suture lines, particularly those involving the coronary ostia, 2) persistent bleeding into the perigraft space if the aorta is sutured in a watertight fashion over the graft, and 3) composite graft infection. ¹ These pseudoaneurysms tend to remain small and asymptomatic, although they upon occasion enlarge, as in our patient, to the point that compression of vital neighboring structures and risk of rupture mandate urgent surgical intervention. Repeat aortic root replacement is a technically challenging procedure, with reported mortality rates ranging from 3.3% to 19%. ^2,3

The 1st difficulty we encountered in our patient was safe reentry into the chest. This was accomplished by instituting CPB before sternotomy. We cannulated the right axillary artery, because retrograde perfusion through the femoral artery is associated with increased risk of embolization of luminal debris from the abdominal aneurysm to the brain. Extensive dissection of aortic and pericardial adhesions was avoided, as this would have prolonged CPB and circulatory arrest times and delayed left ventricular venting and the administration of cardioplegic solution—which in turn would have been detrimental to myocardial protection and would have increased postoperative bleeding.

The interposition of a synthetic graft between the left coronary ostium and the composite graft was necessary because dense adhesions made the creation of a left coronary button unsafe. The right coronary ostium was easily mobilized and was reattached directly to the composite graft without tension. ⁴ The Cabrol technique was avoided because of concerns regarding the fate of the side graft to the right coronary ostium. However, it has been reported that neointimal proliferation is minimal in the graft to the high-flow left main coronary artery in patients receiving warfarin. ⁴

Late aortic complications are more prevalent among Marfan patients with aortic dissection at original operation than among those with chronic aneurysm. Finkbohner and colleagues ⁵ found that more than half of their patients required further aortic operations.

The optimal management strategy—the question of whether procedures should be combined or staged in patients with AAAs greater than 5 cm in diameter and major aortocoronary disease—is still controversial in the surgical community. The proponents of the combined approach cite the increased incidence, well documented, of AAA rupture after major thoracic or abdominal operations. ⁶ They implicate increased collagenase activity as the chief factor that leads to early AAA rupture after major surgical procedures. ⁶ In addition, the combined procedure reduces hospital costs and the length of postoperative stay, due to a single convalescent period. ^6,7 Critics of the combined procedure suggest that there are increased risks of bleeding and other complications (such as respiratory failure) attributable to the overlapping procedures. ⁸ The reported mortality rates for combined coronary artery surgery and AAA resection range from 0 to 30%. ^6–8

We believe, as do others, that selective use of the combined approach is crucial for good results. Patients with poor ejection fraction and prolonged CPB time are at a high risk for the combined procedure. ⁷ Moreover, the current progress of endovascular procedures could mean that aortic stent grafting will take the place of open procedures in many of these patients.

In our patient, the decision to repair both aneurysms at the same time was made on the basis of the high risk of rupture due to the large size of the lesions and on the good general condition of the patient.

In conclusion, elective aortic root replacement or repair in patients with Marfan syndrome is of paramount importance in order to prevent aortic dissection. Even after dissection has occurred, aggressive aortic surgery—with graft replacement of multiple aortic segments—can improve these patients' otherwise dismal prospects for survival. Lifelong imaging of the entire aorta, using MRI or computed tomography, is definitely needed.