Tailoring Aortoplasty for Repair of Fusiform Ascending Aortic Aneurysms

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1 Tailoring Aortoplasty for Repair of Fusiform Ascending Aortic Aneurysms Mark G. Barnett, MD, Andrew C. Fiore, MD, Kathy J. Vaca, RN, Thomas W. Milligan, MD, PhD, and Hendrick B. Barner, MD Departments of Surgery and Pathology, St. Louis University Health Sciences Center, St. Louis, Missouri To evaluate the effectiveness of tailoring aortoplasty used to treat fusiform aneurysms of the ascending aorta, we reviewed the results of operation in 17 patients. Nine patients had tailoring aortoplasty alone, and 8 patients had aortoplasty with Dacron wrap of the ascending aorta. Fourteen of 17 patients were discharged from the hospital, and 12 patients were alive at follow-up between 2 and 120 months. Of two late deaths, neither was due to aneurysmal disease. Actuarial survival at 1 and 10 years was 81% and 63%, respectively. In selected cases, tailoring aortoplasty can achieve long-term results comparable with those of resection and graft replacement of fusiform ascending aortic aneurysms. (Ann Thorac Surg 1995;59: ) D acron graft replacement is the most widely used technique for repair of ascending aortic aneurysrns. This accomplishes aneurysm repair with removal of all or most of the diseased aorta. In some patients, aneurysm formation probably occurs secondary to hemodynamic forces associated with aortic valve disease [1-3]. In these cases, a less radical operation may be done without fear of reformation of the aneurysm after correction of the aortic valvular pathology [4-6]. In selected patients with aneurysmal enlargement confined to the tubular portion of the ascending aorta, we have done a tailoring aortoplasty with resection of a portion of the aortic wall to remodel the ascending aorta and repair the aneurysm. The purposes of this article are to give the long-term results, to describe the technique of tailoring aortoplasty, and to define the specific aortic anatomy suited for this operation. Material and Methods The medical records of patients undergoing tailoring aortoplasty of the ascending aorta at St. Louis University Health Sciences Center and St. Mary's Health Center were reviewed after approval was obtained from the Investigational Review Board. Recent chest radiographs and surgical pathology slides were reviewed. Surviving patients were contacted using a patient questionnaire. Results Between May 1983 and January 1994, 17 patients underwent ascending aortic aneurysm repair using a tailoring aortoplasty. Of 17 patients, 9 had tailoring aortoplasty Accepted for publication Oct 24, Address reprint requests to Dr Barnett, Surgical Specialists, PC, 830 4th Ave SE, Cedar Rapids, IA alone and 8 had both aortoplasty and Dacron wrap of the ascending aorta. Other cardiac procedures were performed in all patients including aortic valve replacement in 16 patients, coronary artery bypass grafts in 3 patients, and mitral valve repair in 2 patients. Intraaortic balloon pump support was used in 2 patients, and a femoralfemoral bypass was done in I of these patients. The mean age was 66 years, with a range from 26 to 87 years. Seven patients were men and 10 were women. Symptoms included angina pectoris in 4 patients, congestive heart failure in 15 patients, and syncope in 3 patients. The indications for operation in this group of patients, in addition to the ascending aortic aneurysm, included symptomatic severe aortic stenosis in 11 patients, severe aortic insufficiency in 5 patients, symptomatic coronary artery disease in 1 patient, and severe mitral regurgitation in 2 patients. Aneurysm size ranged from 5 to 8 cm (Fig 1). This group of patients represented 13.5% of 126 ascending aneurysm repairs and 2.3% of 684 aortic valve replacements done in the same time period. Through a median sternotomy, cardiopulmonary bypass was accomplished with an aortic cannula placed in the proximal transverse aortic arch in 12 patients and femoral arterial cannulation was used in 5 patients. The distal ascending aorta was cross-clamped. The myocardium was protected with intermittent cold blood cardioplegia and topical cold saline solution. The aorta was opened with a longitudinal curvilinear incision along the anterior aspect of the ascending aorta directed toward the noncoronary sinus of Valsalva. In cases of aortic valve disease, the walls of the aneurysrn were retracted with stay sutures, and the valve was excised and replaced. Nine of 11 patients with aortic stenosis were found to have congenitally bicuspid valves. Ten patients had mechanical valves and 6 patients had porcine tissue valves implanted. In 13 of 16 patients, the aortic valve prosthesis implanted was 27 mm or smaller. Other cardiac procedures were performed as required. The size of the 1995 by The Society of Thoracic Surgeons /95/$ (94)

2 498 BARNE"IT ET AL Ann Thorac Surg AORTOPLASTY TO REPAIR ASCENDING ANEURYSMS 1995;59: Fig 3. Outline of tailoring aortoplasty made in the ascending aortic aneurysm. Shaded area represents aortic tissue to be removed. Fig 1. Preoperative aortogram shows an 8-cm ascending aortic aneurysm in an 87-year-old patient with severe aortic insufficiency and coronary artery disease. Note normal size of aortic root and aortic arch. sinuses of Valsalva and location of the coronary artery ostia were normal in all but 1 patient. A tailoring aortoplasty was performed by removing elliptical portions of aortic wall from both sides of the aortotomy totaling between 1 and 4 cm at the widest point and between 5 and 8 cm in length, depending on the size of the aneurysm (Fig 2). This excision was extended from just proximal to the aortic cross-clamp to the superior aspect of the noncoronary sinus of Valsalva away from the origin of the right coronary artery (Fig 3). This reduced the aorta to a normal or near-normal diameter when closed. The aortotomy was closed in two layers using polypropylene suture (Fig 4). Teflon felt strips to reinforce the suture line were used in only 4 of 17 patients. Dacron graft external wrapping of the ascending aorta was used in 8 patients. Coronary vein grafts in 2 patients were anastomosed to the ascending aorta without Dacron wrapping and through a hole in the Dacron wrap in a third patient. Fourteen of 17 patients were discharged from the hospital (82.4%). Two hospital deaths were due to postoperative cardiac failure and arrhythmia at I and 11 days postoperatively, and 1 patient died of renal and respiratory failure after 129 days. The 14 surviving patients left the hospital between 5 and 26 days after the operation, with an average postoperative stay of 10.9 days. Five major postoperative complications occurred in 3 patients. Two patients had postoperative bleeding on the day of the operation. Postoperative respiratory failure developed in Fig 2. Operative photograph shows an ellipse of aortic tissue being excised from the edge of the aortotomy. Note exposure of porcine aortic valve. ~-ig 4. Ascending aorta closed to approximate normal diameter after tailoring aortoplasty and aortic valve replacemenl (Dacron wrap not shown.)

3 Ann Thorac Surg BARNETF ET AL ;59: AORTOPLASTY TO REPAIR ASCENDING ANEURYSMS % Survival IO I i.. I I I I I ½ Years Fig 5. Kaplan-Meier actuarial patient survival curve. 2 patients, and 1 required a tracheostomy. One patient required pacemaker placement for intermittent heart block after tailoring aortoplasty with aortic valve replacement. One additional patient required late reoperation at 4 years for an aortic paravalvular leak and recurrent mitral regurgitation after annuloplasty. The paravalvular leak was closed primarily, the mitral valve was replaced, and the patient recovered well. There were two late deaths due to emphysema and heart failure in both patients at 3 and 6.5 years. Twelve patients were alive at follow-up between 2 and 120 months. The average follow-up period was 4.4 years. All surviving patients are in New York Heart Association functional class I (9 patients) or II (3 patients). Actuarial survival at 1, 5, and 10 years is 81%, 73%, and 63%, respectively (Fig 5). Follow-up chest radiograph or surface echocardiogram (1 patient) performed at a mean of 41.2 months postoperatively with a range of I to 116 months in 11 patients demonstrated no evidence of enlargement of the ascending aorta. The aortic surgical pathology slides were available for 12 patients. Hematoxylin and eosin sections along with sections prepared using alcian blue and elastica-van Gieson stains were reviewed to look for medial degeneration. Evidence of ascending aortic medial degeneration was found in 4 patients (33%), although these medial changes were considered mild in 1. Four of the aortic pathology specimens had some evidence of atherosclerosis. The intimal changes were considered mild in 3 patients and moderate in 1. Comment The anatomy of aneurysrns involving the ascending aorta is highly variable. This variability has led to a number of different operations and techniques for repair of the aneurysm and associated aortic valve pathology. Aneurysms confined to the tubular portion of the ascending aorta that taper to a normal diameter in the distal ascending aorta and with a normal diameter of the sinuses of Valsalva are relatively uncommon, representing 13.5% of our ascending aortic cases. These fusiform aneurysms limited to the ascending aorta are the most suited to tailoring aortoplasty repair (see Fig 3). Aneurysms of the ascending aorta that extend into the transverse aortic arch ideally are treated with a beveled anastomosis to the lesser curvature of the transverse aortic arch with a Dacron graft during hypothermic circulatory arrest. Patients with enlargement of the sinuses of Valsalva, with displacement of the coronary arteries cephalad away from the aortic annulus, along with the enlargement of the ascending aorta are best treated with composite valved graft replacement using either the classic Bentall, modified Bentall (coronary buttons), or Cabrol repair techniques [7]. These operations more effectively replace all of the abnormal aortic tissue affected by primary cystic medial degeneration due to Marfan's syndrome common in these patients. Tailoring aortoplasty has no place in the treatment of aneurysms due to Marfan's syndrome for this reason. Aneurysms that involve the aortic root, the ascending aorta, and transverse aortic arch require a combination of these other techniques for repair. Ascending aneurysms were associated with aortic stenosis in 11 of our patients (65%), and 5 of our patients (29%) had severe aortic insufficiency. The cause of aneurysm formation in this group of patients appears to be hemodynamic forces associated with aortic valvular pathology, because none had other evidence of collagen vascular disease [2, 3]. The medial degeneration that occurs in some of these patients is likely secondary to these hemodynamic factors, although some have suggested intrinsic aortic weakness in patients with bicuspid aortic valves [1, 8]. Modification of hemodynamic factors appears to play a key role in preventing subsequent aortic enlargement in all long-term survivors of tailoring aortoplasty. The decreased radius of the ascending aorta decreases the wall tension proportionally based on the law of Laplace [9]. This also should decrease the likelihood of aortic dissection that is associated with an enlarged aortic segment [10]. Correction of severe aortic valvular stenosis with valve replacement decreases the jet stream and turbulence, thereby decreasing the ascending aortic wall shear stress [2]. Fry [11] has shown that the arterial wall is damaged by high shear stress. Patients with severe aortic insufficiency also have significant turbulence in the ascending aorta [2]. Valve replacement reduces systolic wall tension by reducing both shear stress and the wide pulse pressure with systolic hypertension from the hyperdynamic left ventricle. For these reasons, we believe aortoplasty or graft replacement should be done during other concomitant open heart operations in patients with a good life expectancy with an ascending aortic diameter of more than 5 cm [12]. Fusiform aneurysms of the ascending aorta generally have smooth intimal linings without thrombus or atheroma. This has allowed the use of aortic cross-clamping for repair of aneurysms confined to the ascending aorta with a low risk of distal embolic problems. Carrel and colleagues [4] found a lower incidence of postoperative cerebrovascular complications in patients after tailoring aortoplasty with Dacron wrap when compared with composite valve grafts and supracoronary aortic grafts. An-

4 500 BARNETT ET AL Ann Thorac Surg AORTOPLASTY TO REPAIR ASCENDING ANEURYSMS 1995;59: eurysms extending into the transverse aortic arch are more likely to have atherosclerotic degeneration of the intima in the distal ascending aorta, increasing the risk of distal embolization with the application of a vascular clamp. A cross-clamp also prevents resection of the residual aneurysmal aorta in the aortic arch. Aneurysms due to chronic dissections involving the ascending aorta may contain thrombus within the false lumen, which may embolize with cross-clamping. Dissections of the ascending aorta are not amenable to tailoring aortoplasty. Fusiform aneurysms that develop in the ascending aorta tend to expand anteriorly and toward the right, away from the pulmonary artery, and are accompanied by elongation of the aorta displacing the heart inferiorly and rotating it toward a more horizontal orientation (see Fig 1). Because of this asymmetric expansion, the tailoring resection of aortic tissue should be done toward the right of midline following the greater curve of the aorta as shown in Figure 3. This provides a more normal contour to the aorta after repair than is achieved if the aortic resection is done vertically. This is facilitated by placement of the cross-clamp angled from the right anteriorly toward the left side posteriorly. Care is taken when excising the aortic tissue to keep the ellipse symmetric, with both sides of equal length. This simplifies the aortic closure. Marking the aorta with sutures or an operative marking pen before placement of the crossclamp helps to ensure symmetry and proper location of the site of excision after the aorta is decompressed. Teflon felt strips to reinforce the aortic closure may be used and may increase the strength and hemostasis but are considered optional and have not been employed routinely. Femoral arterial cannulation, although not routinely used, may simplify the operation by providing a less crowded operative field in patients without peripheral vascular disease. Dacron wrapping has been used selectively in these patients and can be a useful adjunct to the operative procedure. The Dacron wrap may serve to reinforce the attenuated wall of the ascending aorta. We have not observed aneurysmal enlargement above or below these Dacron external wraps as noted by Dhillon and colleagues [13] in the descending and abdominal aorta. Those patients without a Dacron wrap of the ascending aorta have not had significant enlargement of their ascending aorta at follow-up. For this reason, we believe that Dacron wrapping is optional in patients of advanced age and may be applied on a case by case basis. However, Egloff and associates [5], Carrel and colleagues [4], and Robicsek [6, 14] favored routine wrapping of the ascending aorta after reduction aortoplasty. Recurrent aneurysm of the ascending aorta after tailoring aortoplasty and Dacron wrap was attributed to slippage of the Dacron in a report by Carrel and associates [41. The satisfactory tailoring of the Dacron external graft is somewhat difficult due to the curvature of the ascending aorta and the relatively short distance from the left main coronary artery to the lesser curvature of the transverse aortic arch when compared with the greater curvature along the right anterolateral aspect. This must be compensated for by beveling the graft at each end to provide coverage over the greater curvature and to avoid impinging on the left main coronary origin. Anchoring sutures as described by Robicsek [6] certainly are helpful to avoid graft migration. Patients treated with tailoring aortoplasty in this series have achieved long-term results that are comparable with those of Dacron graft replacement of fusiform aneurysms of the ascending aorta. Our group of patients achieved an 81% one-year, 73% five-year, and 63% tenyear actuarial survival (see Fig 5). Results were similar in two recent large series of ascending aneurysms treated with composite valved Dacron grafts. The overall survival rate at 5 years was 71% in 348 patients reported by Svensson and associates [7]. The survival was 71% at 5 years and 65% at 7 years in 280 patients reported by Lewis and colleagues [15]. In a study comparing tailoring aortoplasty and Dacron wrap with both composite valved graft replacement and supracoronary graft replacement of the ascending aorta, Carrel and others I4] found a lower operative mortality and better long-term survival in those who had tailoring aortoplasty and wrap. This group also found a lower incidence of postoperative bleeding and significantly shorter aortic cross-clamp and total bypass times in patients undergoing tailoring aortoplasty with Dacron wrap. A tailoring aortoplasty has been a reasonable alternative to graft replacement in patients with aneurysms confined to the ascending aorta. This operation is especially appealing for use in elderly patients who have associated severe aortic valvular pathology. Twelve of our 17 patients (71%) were older than 65 years. Correction of the aortic valvular pathology and restoration of the aorta to normal size may help prevent subsequent aortic dilatation by correction of hemodynamic forces. This operation is less radical than Dacron graft replacement and may decrease the aortic cross-clamp time, which is advantageous in high-risk elderly patients. References 1. Hahn RT, Roman MJ, Mogtader AH, Devereux RB. Association of aortic dilation with regurgitant, stenotic and functionally normal bicuspid aortic valves. J Am Coll Cardiol 1992;19: Stein PD, Sabbah HN. Turbulent blood flow in the ascending aorta of humans with normal and diseased aortic valves. Circulation 1976;39: Jarchow BH, Kincaid OW. Poststenotic dilatation of the ascending aorta: its occurrence and significance as a roentgenologic sign of aortic stenosis. Mayo Clin Proc 1961;36: Carrel T, yon Segesser L, Jenni R, et al. Dealing with dilated ascending aorta during aortic valve replacement: advantages of conservative surgical approach. Eur J Cardiothorac Surg 1991;5: Egloff L, Rothlin M, Kugelmeier J, Senning A, Turina M. The ascending aortic aneurysm: replacement or repair? Ann Thorac Surg 1982;34: Robicsek F. A new method to treat fusiform aneurysms of the ascending aorta associated with aortic valve disease: an alternative to radical resection. Ann Thorac Surg 1982;34: 92-4.

5 Ann Thorac Surg BARNETT ET AL ;59: AORTOPLASTY TO REPAIR ASCENDING ANEURYSMS 7. Svensson LG, Crawford ES, Hess KR, Coselli JS, Sati JH. Composite valve graft replacement of the proximal aorta; comparison of techniques of 348 patients. Ann Thorac Surg 1992;54: Lindsay J. Coarctation of the aorta, bicuspid aortic valve and abnormal ascending aortic wall. Am J Cardiol 1988;61: Nerum RM. Arterial fluid dynamics and interactions with the vessel wall. In: Schwartz CJ, Werthessen NT, Wolf S, eds. Structure and function of the circulation. Vol 2. New York: Plenum, 1981: Crawford ES, Svensson LG, Coselli JS, Sail HJ, Hess KR. Aortic dissection and dissecting aortic aneurysms. Ann Surg 1988;208: Fry DL. Acute vascular endothelial changes associated with increased blood velocity gradients. Circ Res 1968;22: Crawford ES, DeNatale RW. Thoracoabdominal aortic aneurysm: observations regarding the natural course of the disease. J Vasc Surg 1986;3: Dhillon JS, Randhawa GK, Straehley CJ, McNamara JJ. Late rupture after Dacron wrapping of aortic aneurysm. Circulation 1986;74(Suppl 1): Robicsek F, Thubrikar MJ. Conservative operation in the management of annular dilatation and ascending aortic aneurysm. Ann Thorac Surg 1994;57: Lewis CTP, Cooley DA, Murphy MC, Talledo O, Vega D. Surgical repair of aortic root aneurysms in 280 patients. Ann Thorac Surg 1992;53: INVITED COMMENTARY Most aneurysms are caused by abnormally high wall stress, and most aneurysms rupture because of abnormally high wall stress--a force that acts on the aortic wall and is directly proportional with the aortic diameter and inversely with wall thickness and strength. The conventional way to bring wall stress down to normal and thus prevent rupture, is to replace the aneurysmatic aortic segment with a synthetic vascular prosthesis of appropriate diameter and strength. Although in the majority of patients this indeed remains the method of choice, in some special situations where the anatomy is favorable, such as is the case in "pear" or "teardrop"-shaped aneurysms of the ascending aorta, aortoplasty, a less radical procedure, may suffice. Such an approach has been applied by my colleagues and me for the past two decades for the treatment of some ascending aortic aneurysms and more recently by Williams for the management of chronic descending aortic dissections. In this article, Barnett and associates also make a strong case in favor of aortoplasty. There are, however, several points with which I disagree with them, both in technique and in indication. They use external wall reinforcement only selectively, and in about half of their patients aortic remodeling was applied alone. This approach, although it effectively addresses one of the principal components of increased wall stress, ie, the aortic diameter, leaves the second equally important contributor, wall thickness and strength, unattended. In other words, aortoplasty eliminates the aneurysm, but it does not prevent recurrence! If the patient otherwise would live long enough, the same factor that caused the aorta to dilate in the first place, the weakness of the aortic wall, would lead to aneurysm formation again. Recognizing the above, I recommend that aortic remodeling always should be combined with wall reinforcement using an externally applied, well-tailored Dacron vascular prosthesis. My colleagues and I have shown this combined procedure to have a long and a respectable follow-up with results comparable with or better than those of radical aortic root replacement. Exceptions to this recommendation may be moderatesized poststenotic aneurysms in which the cause of the dilatation, ie, stenosis, has been surgically corrected. Aortoplasty alone as applied by Barnett and associates may suffice in patients with advanced age whose lifetime is too short for their aneurysm to recur or in remodeling those with poststenotic ascending aortic dilatations that most probably would not rupture anyhow. It seems, however, to be highly inadequate for younger patients including those with Marfan's syndrome--a group Barnett and associates wisely avoided in their series of unprotected aortoplasties. By the way, I do not believe that Marfan's disease represents a contraindication to aortic remodeling, but remodeling should be combined with external wall reinforcement (I do not like to use the word "wrapping" because it is reminiscent of the cellophane "wrap" of the 1950s). As a matter of fact, I regard ascending aortic dilatations of medium to severe size in a patient with Marfan's syndrome as an ideal indication for aortic remodeling, especially if the procedure requires a valve replacement, because of annular dilatation. Similarly, I do not hesitate to perform aortic remodeling if the sinuses of Valsalva are dilated as well, but only if there is a need for aortic valve replacement, and thus the aortic annulus is stabilized by the insertion of a prosthetic valve. In such cases the aortoplasty is carried deep into the noncoronary sinus and the externally applied Dacron tube is anchored to the valve prosthesis using sutures carried through the aortic wall. In conclusion, in my view, about a third of the patients with ascending aortic aneurysms, including those with Marfan's traits, could be safely and effectively treated with aortic remodeling instead of graft replacement, especially if they require aortic valve replacement as well. The normal aortic geometry, thus restored, should be further secured by the external application of a wellfitted Dacron vascular graft anchored proximally to either the commissures or, if a prosthetic valve was implanted, to the prosthetic valve itself. Francis Robicsek, MD Department of Cardiothoracic and Vascular Surgery The Sanger Clinic, PA 1001 Blythe Blvd Suite 300, PO Box Charlotte, NC 28203