Valve-Sparing Aortic Root Replacement: Early Experience With the De Paulis Valsalva Graft in 51 Patients

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1 Valve-Sparing Aortic Root Replacement: Early Experience With the De Paulis Valsalva Graft in 51 Patients Nishant D. Patel, BA, Jason A. Williams, MD, Christopher J. Barreiro, MD, Brian T. Bethea, MD, Torin P. Fitton, MD, Harry C. Dietz, MD, Joao A. C. Lima, MD, Philip J. Spevak, MD, Vincent L. Gott, MD, Luca A. Vricella, MD, and Duke E. Cameron, MD Divisions of Cardiac Surgery, Cardiology, and Pediatric Cardiology, and McKusick-Nathans Institute of Genetic Medicine, The Johns Hopkins Medical Institutions, Baltimore, Maryland Background. Valve-sparing aortic root replacement for treatment of aortic sinus disease avoids the problems of prosthetic valves, but some patients suffer late valve incompetence as a result of leaflet distortion or annular dilatation. The reimplantation technique using the De Paulis Valsalva graft might improve late results of valvesparing aortic root replacement by maintaining annular stability and re-creating sinuses that minimize leaflet stress. Methods. Retrospective review was conducted of all patients at our institution who underwent valve-sparing aortic root replacement using the Valsalva graft. Clinical data were obtained from hospital and clinic charts and patient contacts; echocardiograms were analyzed for aortic root dimensions and valve function. Results. Between May 2002 and June 2005, 51 patients underwent valve-sparing aortic root replacement using the reimplantation technique with the Valsalva graft. Mean age was years; 22% (11 of 51) were children, and 80% (41 of 51) were male. Primary indication for surgery was root aneurysm in all patients. Preoperative mean root diameter was cm. Marfan syndrome was present in 67% (34 of 51), and 10% (5 of 51) had the newly described Loeys-Dietz syndrome. There were no operative or late deaths, and no patient required reoperation for bleeding. At mean follow-up of 1.8 years, there were no episodes of endocarditis or thromboembolism. Echocardiograms showed stability of the annulus and root dimensions on follow-up. No patient had more than 0 to 1 aortic insufficiency or progression of aortic insufficiency. All were in New York Heart Association class I. Conclusions. Valve-sparing aortic root replacement using the Valsalva graft and reimplantation technique has excellent early results. Preservation of valve competence is encouraging, but long-term results will determine whether the anatomic design of this aortic root prosthesis is superior for preservation of valve integrity. (Ann Thorac Surg 2006;82:548 53) 2006 by The Society of Thoracic Surgeons Since its introduction by Bentall and de Bono in 1968 [1], aortic root replacement with a composite graft has been the traditional surgical approach for patients with aortic root and valve disease. Many studies have reported low operative risk and excellent late results after the Bentall procedure [2 4]. Nevertheless, the mechanical valve prosthesis necessitates life-long anticoagulation and carries an ongoing risk of thromboembolism and endocarditis. On the other hand, bioprosthetic valves likely require reoperation for valve deterioration in young patients. Valve-sparing aortic root replacement (VSRR) has been pioneered by Sarsan and Yacoub [5] and David and Accepted for publication March 22, Presented at the Poster Session of the Forty-second Annual Meeting of The Society of Thoracic Surgeons, Chicago, IL, Jan 30 Feb 1, Address correspondence to Dr Cameron, Division of Pediatric Cardiac Surgery, 600 N Wolfe St, Blalock 618, Baltimore, MD 21287; dcameron@csurg.jhmi.jhu.edu. Feindel [6] in an effort to improve quality of life of patients by avoiding the potential complications of valve prostheses. Valve-sparing aortic root replacement is an option for patients with aortic aneurysm, aortic dissection, or annuloaortic ectasia in the presence of normal or near-normal aortic valve leaflets; however, long-term results after VSRR have been imperfect, usually as a result of late valve incompetence. Late aortic insufficiency (AI) after the reimplantation (David I) procedure [6], which does not reconstruct anatomic aortic sinuses, has been attributed to leaflet stress [7], although longterm results have yet to confirm these findings. Longterm outcome after the remodeling (Yacoub/David II) procedure [5, 8] has been complicated by valve incompetence and AI caused by late annular dilatation [9, 10]. Consequently, some VSRR patients ultimately require aortic valve replacement. Our practice with VSRR has evolved. We began with the remodeling procedure in 1993, as we believed preserving sinuses would be important for aortic valve 2006 by The Society of Thoracic Surgeons /06/$32.00 Published by Elsevier Inc doi: /j.athoracsur

2 Ann Thorac Surg PATEL ET AL 2006;82: VSRR WITH THE VALSALVA GRAFT 549 competence. However, we and others [9, 10] noted that some patients developed significant AI as a result of annular dilatation that necessitated aortic valve replacement. We embraced the reimplantation (David I) technique at the same time the De Paulis Valsalva graft became available [11], and began using both in May 2002 with hope that the Valsalva graft would stabilize the annulus and preserve sinuses, minimizing leaflet stress and maintaining natural opening and closing characteristics. This study was undertaken to assess early results of the reimplantation procedure using the Valsalva graft. Patients and Methods Study Design, Patient Selection, and Patient Variables We have used the reimplantation technique and the Valsalva graft exclusively in all VSRR operations since May After institutional review board approval, data were collected retrospectively for 51 consecutive VSRR patients from May 2002 to July 2005 using medical and electronic patient records. A waiver for individual consent was granted by our institutional review board. Transthoracic echocardiograms (TTE) were the primary imaging modality for assessing preoperative, immediate postoperative, and most recent postoperative aortic valve function. Echocardiographic data included dimensions of maximum aortic root diameter, annular diameter, and sinotubular junction diameter, as well as the degree of AI. All VSRR patients were asked to undergo TTE, computed tomography, or magnetic resonance imaging 6 months postoperatively, and annually thereafter to monitor aortic root diameter and valve competence. Clinical follow-up data were obtained by telephone interview with the patient, family members, or primary care physicians. We consider a preoperative annular diameter greater than 34 mm, marked leaflet fenestration and asymmetry, acute aortic dissection in unstable patients, and severe AI or a giant root with marked leaflet irregularities as relative contraindications to VSRR. Although we have successfully reconstructed bicuspid aortic valves, we do not perform VSRR on bicuspid valves with marked calcification, prolapse, thickening, or fenestrations. Operative Technique Our operative technique has been described elsewhere [12]. Briefly, all patients undergo full median sternotomy and are placed on cardiopulmonary bypass using aortic and bicaval venous cannulation. We use bicaval venous cannulation to enable routine exploration and closure of patent foramen ovale, which occurs in one third of our patients; bicaval cannulation also improves exposure of the aortic root. A vent is placed in the left atrium through the right superior pulmonary vein. After aortic crossclamping and cardioplegic arrest, the aorta is divided above the sinotubular ridge. We determine the diameter of the sinotubular junction that provides optimal leaflet apposition using valve sizers and select a Valsalva graft that is 2 to 3 mm larger, as the prosthesis fits outside the aortic valve complex. In adults, this is usually a 30- or 32-mm graft. The base of the aorta is dissected externally down to a subannular level, followed by excision of sinus tissue, leaving approximately 4 to 5 mm of remnant sinus tissue attached to the annulus. The coronary arteries are mobilized widely. Exposure of the root and proper orientation of the coronary arteries is maintained by stay sutures at the top of the three commissures and the coronary buttons. Three 2-0 braided polyester, nonpledgetted horizontal mattress sutures are passed under the annulus at the nadir of each aortic leaflet from inside outward. Our procedure differs from the original David I reimplantation technique [6] in that only three subannular sutures are placed. The subannular sutures anchor the graft in place and are not part of the hemostatic suture line. The proximal collar of the graft is trimmed to two to three rings. The surgeon should take note that the Valsalva graft is a flammable, gelatin-impregnated conduit. Therefore, electrocautery should be avoided unless the graft is moistened. We prefer to use scissors to trim the graft. The distal end of the graft is usually trimmed to four to five rings, but may be left longer if more extensive replacement of the ascending aorta or arch is necessary. The three subannular sutures are passed inside out through the bottom of the Valsalva graft 120 degrees apart from one another. The stay sutures are pulled up within the graft, which is lowered around the valve complex, and the three subannular sutures are tied. The commissures are fixed to the sinotubular junction of the graft using three 4-0 polypropylene pledgetted mattress sutures. In most patients the commissure height is level with the sinotubular ridge of the graft. In patients with very large roots and tall commissures, fixation can be just above the ridge. It is worth noting that the skirt of the graft is somewhat self-adjusting to the height of the commissures. The valve is now properly positioned within the graft by the three below and three above fixation sutures. If the graft is significantly larger than the annulus, additional subannular mattress sutures can be placed to plicate the graft down to the annular size, although this is rarely required. Starting at the bottom of each sinus and sewing upward to the commissure tops, continuous 4-0 polypropylene sutures are used to fix the sinus remnant and annulus within the graft. This is the hemostatic suture line and must be performed carefully. Holes are cut in the graft opposite the coronary artery buttons. We encircle the coronary buttons with Teflon felt lifesaver pledgets. The left and the right coronary anastomoses are completed with 4-0 polypropylene. Finally, the distal graft is anastomosed to the aorta using continuous 4-0 polypropylene suture and an external felt strip. Air is evacuated from the heart, the aortic crossclamp is removed, and the heart is resuscitated. Postoperative Care All patients in this study were maintained on aspirin for 1 month. Patients were also maintained on long-term

3 550 PATEL ET AL Ann Thorac Surg VSRR WITH THE VALSALVA GRAFT 2006;82: Table 1. Clinical Characteristics of Pediatric and Adult Patients Undergoing Valve-Sparing Aortic Root Replacement With the Valsalva Graft and Reimplantation Technique Characteristic All Patients n 51 (%) Pediatric Patients n 11 (%) Adult Patients n 40 (%) Mean age at operation (y) Male 41 (80.4) 6 (54.5) 35 (87.5) Race Caucasian 47 (92.1) 9 (81.8) 38 (95.0) African American 1 (2.0) 1 (9.1) 0 (0) Hispanic 3 (5.9) 1 (9.1) 2 (5.0) Diagnosis Marfan syndrome 34 (66.7) 6 (54.5) 28 (70.0) Nonspecific 12 (23.5) 0 (0) 12 (30.0) connective tissue Loeys-Dietz 5 (9.8) 5 (45.5) 0 (0) syndrome Indication for VSRR Aortic root aneurysm 51 (100) 11 (100) 40 (100) VSRR valve-sparing aortic root replacement. -blockers and antibiotic prophylaxis, as previously reported [9, 12]. Statistical Analyses Statistical analyses were conducted with SPSS (SPSS, Inc, Chicago, IL) software package. Univariate analysis of changes in aortic root diameters was performed. Survival and freedom from greater than 1 AI were calculated using the Kaplan Meier method. All data are presented as mean standard deviation, unless otherwise noted. Results Preoperative Clinical Characteristics Fifty-one consecutive patients underwent VSRR using the reimplantation technique and Valsalva graft (age range, 1.3 to 60.7 years). Clinical characteristics are listed in Table 1. Diagnoses among pediatric patients were Marfan syndrome in 54.5% (6 of 11) and the newly described Loeys- Dietz syndrome in 45.5% (5 of 11). Diagnoses among adults were Marfan syndrome in 70.0% (28 of 40) and nonspecific connective tissue disorder in 30.0% (12 of 40). All pediatric patients were preoperatively in New York Heart Association class I. Preoperative New York Heart Association class in adults was I in 77.5% (31 of 40), II in 10.0% (4 of 40), III in 10.0% (4 of 40), and IV in 2.5% (1 of 40). Primary indication for VSRR in both adult and pediatric patients was aneurysm of the aortic root. Operative Data Valsalva graft size distribution is shown in Figure 1. The 32-mm Valsalva graft, used in 2 pediatric and 18 adult patients, was the most common size. Cardiopulmonary bypass and cross-clamp times and concomitant surgical procedures are listed in Table 2. Patent foramen ovale was a common finding and was closed in 7 pediatric and 13 adult patients. One pediatric patient underwent right coronary artery plication for aneurysm in addition to patent foramen ovale closure, and another underwent ligation of a patent ductus arteriosus. Two adult patients had true atrial septal defects, which were repaired concomitantly. One adult patient required coronary artery bypass grafting and hemiarch replacement (Hemashield Dacron graft), a second required mitral annuloplasty, and a third underwent mitral annuloplasty in addition to patent foramen ovale closure. Aortic Root Diameters, Aortic Insufficiency, and Aortic Valve Replacement Table 3 presents TTE data for all VSRR patients. All patients underwent preoperative TTE. A postoperative in-hospital TTE was available for 41 patients. Most recent postoperative TTE was available for 46 patients. Mean preoperative maximum aortic root, sinotubular junction, and annular diameters were , , and cm, respectively. As expected, immediate postoperative echocardiograms demonstrated significantly smaller mean maximum aortic root, sinotubular junction, and annular diameters on univariate analysis. Most recent postoperative echocardiograms showed no significant annular, root, or ascending aortic dilatation compared with the immediate postoperative period, confirming the stability of the aortic root achieved by the reimplantation technique. Aortic insufficiency was assessed by TTE preoperatively, postoperatively before discharge, and postoperatively after discharge. Preoperatively, 86.3% (44 of 51) had 0to1 AI, whereas 13.7% (7 of 51) had 2 to 4 AI (Fig 2). The 7 patients with preoperative 2 to 4 AI demonstrated a mean maximum aortic root diameter of cm. Five of these patients were adults, 4 had nonspecific connective tissue disorders, 1 had Marfan syndrome, and 1 had Loeys-Dietz Syndrome. On follow-up, no patient had more than 1 AI on TTE (freedom from 1 AI, 100% at 2 years; mean time to most recent echocardiogram, 13 months). Equally important, no patient showed progression from 0 to 2 AI, and no additional surgery was required in any patient for progression of AI or aortic root instability. Fig 1. Valsalva graft size distribution in pediatric (striped bars) and adult (black bars) patients.

4 Ann Thorac Surg PATEL ET AL 2006;82: VSRR WITH THE VALSALVA GRAFT 551 Table 2. Operative Data in Pediatric and Adult Patients Undergoing Valve-Sparing Aortic Root Replacement With the Valsava Graft and Reimplantation Technique Variable All Patients n 51 (%) Pediatric Patients n 11 (%) Adult Patients n 40 (%) Mean cross-clamp time (min) Mean CPB time (min) Procedure VSRR Alone 26 (51.0) 3 (27.2) 23 (57.5) VSRR PFO closure 18 (35.3) 6 (54.5) 12 (30.0) VSRR PFO closure plication of RCA 1 (2.0) 1 (9.1) 0 (0) VSRR PDA ligation 1 (2.0) 1 (9.1) 0 (0) VSRR ASD repair 2 (3.9) 0 (0) 2 (5.0) VSRR hemiarch replacement CABG 1 (2.0) 0 (0) 1 (2.5) VSRR mitral ring annuloplasty 1 (2.0) 0 (0) 1 (2.5) VSRR PFO mitral ring annuloplasty 1 (2.0) 0 (0) 1 (2.5) ASD atrial septal defect; CABG coronary artery bypass grafting; CPB cardiopulmonary bypass; PDA patent ductus arteriosus; PFO patent foramen ovale; RCA right coronary artery; VSRR valve-sparing root replacement. Postoperative Complications In-hospital and postoperative complications are listed in Table 4. No patient required reoperation for bleeding. Ten (19.6%) patients had atrial fibrillation in the immediate postoperative period. Nine converted to sinus rhythm before discharge with amiodarone and metoprolol. The tenth patient, a 52-year old man, was in atrial fibrillation preoperatively and remains in atrial fibrillation 2 years after VSRR. One patient who underwent concomitant coronary artery bypass grafting at the time of VSRR suffered a cerebrovascular accident immediately postoperatively, resulting in left hemiparesis. He continues to report left-sided weakness 2 years later, but is improved. The 2 patients who had concomitant mitral valve annuloplasty had no significant perioperative or postoperative morbidity. Survival and Functional Outcomes Follow-up was 100% complete at a mean of years (range, 0.5 to 3.4 years). There have been no operative or late deaths and survival is 100% at 3 years. All patients are New York Heart Association class I. Comment Recent years have seen considerable growth and interest in VSRR operations for aortic root disease. Several reports have confirmed low operative risk and excellent freedom from thromboembolism and endocarditis. Late aortic valve incompetence, however, has remained the Achilles heel of VSRR. The reimplantation technique affords better long-term results in this regard [13, 14], but has usually been performed using straight Dacron grafts. Whether a graft that re-creates sinuses will further improve late results is an unanswered question, and was the impetus for this preliminary study. In a study of 230 patients undergoing VSRR, David and associates [10] recently reported outcomes in patients undergoing remodeling or reimplantation for aortic root aneurysm or ascending aortic aneurysm with significant AI. The authors report 83% and 36% 8-year survival for patients undergoing reimplantation and remodeling for aortic root and ascending aortic aneurysms with AI, respectively. As reported by the authors, many patients in this study demonstrated late valve incompetence. Freedom from significant AI at 8 years was approximately 90% for patients who underwent reimplantation, and 55% for those who underwent remodeling. The authors concluded that reimplantation provides a more stable repair than the remodeling procedure. Kallenbach and colleagues [15] also reported their experience with the reimplantation procedure using a straight Dacron conduit in 158 consecutive patients. The authors reported excellent results, with a low operative mortality of 4%. In that series, 4% of patients required late aortic valve replacement because of valve incompetence. In a more Table 3. Preoperative, Immediate Postoperative, and Most Recent Postoperative Root Diameters on Echocardiogram Variable Preoperative (n 51) Immediate Postoperative (n 41) Most Recent Postoperative (n 46) a p Value b p Value c Maximum root (cm) STJ (cm) Annular (cm) a Mean time to postoperative echocardiogram was 13 months, for a total of 575 months. b Preoperative versus immediate postoperative. c Immediate postoperative versus most recent postoperative. STJ sinotubular junction.

5 552 PATEL ET AL Ann Thorac Surg VSRR WITH THE VALSALVA GRAFT 2006;82: Fig 2. Aortic insufficiency (AI) in patients undergoing reimplantation with the Valsalva graft. recent study of their experience, Kallenbach and coworkers [16] reported a 10-year survival of 80%, when excluding early deaths, and a freedom from reoperation for valve incompetence of 87% in 284 patients undergoing VSRR with straight grafts. The authors noted that 13% of patients with Marfan syndrome required a second operation on the reconstructed aortic valve. Despite these good results after the reimplantation procedure with straight grafts, we believe that the sinuses are important for the long-term function of the aortic root and aortic valve. An early study from Bellhouse [17] demonstrated the importance of the sinotubular junction in creating eddy currents at the onset of systole that prevent the leaflets from hitting the aortic wall. Furthermore, eddy currents were found to diminish leaflet stress during closure. Similarly, Thubrikar and colleagues [18] demonstrated the importance of the curvature of the sinuses in distributing leaflet stress. More recent studies have confirmed these earlier results. Leyh and coworkers [7] have shown that the absence of sinuses after the reimplantation procedure with a straight Dacron conduit negatively impacts valve function and that re-creation of sinuses with the remodeling operation leads to more natural leaflet motion. Grande-Allen and associates [19] have shown in a finite element study that re-creation of the sinuses reduces leaflet stress during valve closure, which theoretically should improve leaflet durability. We recently reported our experience with all VSRR operations between 1994 and 2002 [9]. During this study period, 65 patients underwent VSRR; 58 patients underwent the remodeling procedure and 7 underwent reimplantation. Our early results were excellent, with no operative or hospital deaths and no significant perioperative morbidity. One patient died at late follow-up as a result of salmonella meningitis. Furthermore, no patient exhibitied thromboembolism or endocarditis. Despite the excellent survival, 10 patients in our initial report demonstrated late valve incompetence with significant AI. Nine of these 10 patients had a remodeling procedure, and in 8 patients significant AI developed secondary to late annular dilatation. One patient experienced late valve incompetence and significant AI approximately 8 years after a reimplantation procedure as a result of aortic leaflet distortion and prolapse. This patient subsequently required aortic valve replacement. Freedom from aortic valve replacement in our entire 65-patient series was 84% at 5 years [9]. This experience led us to reconsider the reimplantation procedure to provide annular stability. The Valsalva graft was introduced by De Paulis and colleagues in 2000 [11]. In the original report, the authors evaluated outcomes after composite graft replacement, remodeling, and reimplantation with the Valsalva graft. The authors reported no operative mortality and excellent early postoperative results. In a more recent study, De Paulis and associates [20] reported outcomes in 28 patients 1 year after composite replacement, reimplantation, and remodeling with the Valsalva graft. In that study, the authors demonstrated that patients undergoing reimplantation with the Valsalva graft had a significantly smaller annular diameter, less bleeding, and less residual AI. Nevertheless, the authors stressed that a larger patient cohort and longer follow-up were warranted to determine whether reimplantation with the Valsalva graft consistently produced a more natural aortic root with stable results, and we concur. Selection of the appropriate size of the Valsalva graft is often a critical step for a successful VSRR. We have avoided formulas based on annular size as we believe the sinotubular junction diameter is usually the more important dimension. As noted in our Methods section, we selected a Valsalva graft with a diameter 2 to 3 mm larger than the optimal sinotubular junction diameter. The Valsalva graft is available in diameters from 24 to 34 mm, which we believe accommodates the vast majority of patients who are eligible for VSRR. It is our belief that patients with an optimal Table 4. Immediate and Most Recent Postoperative Complications for Patients Undergoing Valve-Sparing Aortic Root Replacement With the Valsalva Graft and Reimplantation Technique Variable No. of Patients (%) n 51 Immediate postoperative period Arrhythmias 10 (19.6) Atrial fibrillation 7 (13.7) Junctional 1 (2.0) Sinus tachycardia 2 (3.9) CVA 1 (2.0) Sternal wound infection a 1 (2.0) Reoperation for bleeding 0 (0) Most recent postoperative period Atrial fibrillation b 1 (2.0) a This patient developed a sternal wound infection 19 days after valvesparing aortic root replacement, was unsuccessfully treated with antibiotics, and underwent sternal debridement 24 days after valve-sparing aortic root replacement. b Patient had atrial fibrillation in the immediate postoperative period. CVA cerebrovascular accident.

6 Ann Thorac Surg PATEL ET AL 2006;82: VSRR WITH THE VALSALVA GRAFT 553 sinotubular junction diameter larger than 34 mm are probably not good candidates for VSRR because of leaflet elongation. However, the Valsalva graft can accommodate larger aortic roots because the graft still permits placement of the commissures just above the sinotubular ridge of the graft. Unlike previous reports on the Valsalva graft from De Paulis and colleagues [11, 20], the majority of our patients (67%) have Marfan syndrome. There has been much skepticism about the role of VSRR in patients with Marfan syndrome. Our study is unique in the high proportion of Marfan syndrome patients, and we have shown that VSRR is a safe procedure with excellent early results. Although many other studies include Marfan patients, these patients usually constitute only a minority of the cohort. Patients with Marfan syndrome often represent the most challenging cases for VSRR, and therefore the proportion of Marfan patients should always be noted when comparing results of studies. This study is also unique in that it includes 5 children with the newly described Loeys-Dietz syndrome [21]. This familial aneurysm syndrome is Marfan-like, but is distinguished by much more aggressive vascular disease. These patients are at risk of aortic root rupture and dissection at smaller diameters than observed in Marfan patients. Phenotypically, these patients can be distinguished from Marfan patients by the presence of hypertelorism, low-set ears, and bifid uvula. It is important to note that all patients in this study who demonstrated phenotypic features of connective tissue disorders were evaluated by medical geneticists for diagnostic confirmation. In summary, we have used the reimplantation procedure with the Valsalva graft exclusively since May Reimplantation with the Valsalva graft maintains annular stability and provides prefashioned sinuses that allow normal valve function during the cardiac cycle. Our initial results in 51 patients demonstrate no dilatation, no significant AI, and no progression of AI. Furthermore, no patient in our study has required reoperation for bleeding and there have been no deaths in our series. Our study is limited by the number of patients and relatively short follow-up. A larger patient series and longer follow-up are necessary to determine whether the Valsalva graft and reimplantation technique are superior for long-term valve competence, and whether it can match or surpass the excellent long-term results with composite grafts. This study was supported in part by the Dana and Albert Cubby Broccoli Center for Aortic Diseases at the Johns Hopkins Medical Institutions, by the Mildred and Carmont Blitz Cardiac Research Fund, National Institutes of Health grant R01-AR41135, The Howard Hughes Medical Institute, the Smilow Family Foundation, and an Alpha Omega Alpha Student Research Fellowship. Nishant Patel is a 2005 Alpha Omega Alpha Student Research Fellow; Drs Jason Williams and Torin Fitton are Irene Piccinini Investigators; Drs Christopher Barreiro and Brian Bethea are Hugh R. Sharp Jr. Research Fellows; and Dr Duke Cameron is the James T. Dresher, Sr. Professor of Surgery. References 1. Bentall HH, De Bono A. A technique for complete replacement of the ascending aorta. Thorax 1968;23: Kouchoukos NT, Marshall WG, Wedige-Stecher TA. Elevenyear experience with composite graft replacement of the ascending aorta and aortic valve. J Thorac Cardiovasc Surg 1986;92: Gott VL, Greene PS, Alejo DE, et al. 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