Several previous reports have recorded the evolution

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1 Impact of Concomitant Coronary Artery Bypass Grafting on Hospital Survival After Aortic Root Replacement John G. Byrne, MD, Alexandros N. Karavas, MD, Marzia Leacche, MD, Daniel Unic, MD, James D. Rawn, MD, Gregory S. Couper, MD, Tomislav Mihaljevic, MD, Robert J. Rizzo, MD, Sary F. Aranki, MD, and Lawrence H. Cohn, MD Division of Cardiac Surgery, Brigham and Women s Hospital, Boston, Massachusetts Background. We examined the impact of concomitant coronary artery bypass grafting (CABG) on hospital survival after aortic root replacement. We sought to determine whether CABG procedures that were not originally planned but rather added after the aortic root procedure was completed (CABG/bailout) skewed the results to shift patients with bad outcomes to the CABG group, making the non-cabg group appear undeservedly low risk. Methods. Between May 1992 and January 2001, 369 consecutive patients underwent aortic root replacement. Concomitant CABG was required in 95 patients (26%). Indications for CABG were significant coronary artery disease in 73 patients (20%), active endocarditis or acute aortic dissection involving the coronary orifices in 14 patients (4%), and difficulty weaning from bypass because of regional wall motion abnormality from presumed but unconfirmed coronary artery disease or technical error at coronary ostial reimplantation (CABG/ bailout) in 8 patients (2%). Results. Operative mortality for the entire cohort was 5.7% (21 patients). The operative mortality rate for the non-cabg group was 0.4% (1 of 274 patients), and for the CABG group, 21% (20 of 95 patients; p < 0.001). Independent predictors of operative mortality in the CABG group were New York Heart Association functional class III or IV (odds ratio, 3.9; 95% confidence interval, 1.07 to 14.5), active endocarditis (odds ratio, 9.2; 95% confidence interval, 2.06 to 41.5), acute aortic dissection (odds ratio, 7.6; 95% confidence interval, 1.81 to 32.0), and failure to use retrograde cardioplegia (odds ratio, 6.4; 95% confidence interval, 1.06 to 38.8). The use of CABG/bailout was not a predictor. Conclusions. Adding CABG at the end of an aortic root procedure is a rare event, and because it is rare, there is no significant shift of risk as a result of the CABG/bailout patients on the overall CABG group. (Ann Thorac Surg 2005;79:511 6) 2005 by The Society of Thoracic Surgeons Several previous reports have recorded the evolution of aortic root surgery [1]. Postoperative morbidity and mortality have decreased substantially with advances in operative technique and perioperative care. Among those patients undergoing aortic root surgery, concomitant coronary artery bypass grafting (CABG) is often deemed necessary. Concomitant CABG has been shown to increase operative risk [2]. Indications include the presence of known coronary artery disease (CAD) or the destruction of the coronary ostia by endocarditis or aortic dissection. Furthermore, in some patients, CABG is deemed necessary after the aortic root procedure is completed. This can be as a result of a technical error in the coronary button anastomosis or because of regional wall motion abnormalities after separating from bypass from suspected but unconfirmed CAD or myocardial Accepted for publication July 19, Address reprint requests to Dr Byrne, Division of Cardiac Surgery, Brigham and Women s Hospital, 75 Francis St, Boston, MA 02115; jbyrne@partners.org. protection error. These are patients who, although not initially planned for CABG, cross over to the CABG group (CABG/bailout). No studies have reported the effect that these patients may have on the postoperative morbidity and mortality of the CABG group. Patients and Methods Patients Between May 1992 and January 2001, 369 consecutive patients underwent aortic root surgery at the Brigham and Women s Hospital. After approval by the institutional review board, medical records were reviewed. Median age was 51 years (range, 19 to 90 years), and 108 patients (29%) were female. Ejection fraction ranged between 0.15 and 0.85 (median, 0.60), and 145 patients (39%) had New York Heart Association functional class III or IV symptoms. Aortic valve regurgitation was evident on presentation in 199 patients (54%), aortic stenosis in 84 patients (23%), mixed regurgitation and stenosis in 36 patients (10%), and other pathologic processes (endo by The Society of Thoracic Surgeons /05/$30.00 Published by Elsevier Inc doi: /j.athoracsur

2 512 BYRNE ET AL Ann Thorac Surg CABG AND SURVIVAL AFTER AORTIC ROOT REPLACEMENT 2005;79:511 6 Fig 1. The operative mortality (OM) rate for the entire non coronary artery bypass grafting (CABG) group (top right) was 0.4% (1 of 274 patients), whereas the operative mortality rate for the entire CABG group (bottom right) was 21% (20 of 95 patients; p 0.001). The operative mortality rate for the CABG/coronary artery disease group (bottom left, gray) was 19% (14 of 73 patients), for the CABG/coronary orifice group (bottom left, white) was 29% (4 of 14 patients), and for the CABG/bailout group (middle of figure) was 25% (2 of 8 patients). The operative mortality rate in patients initially planned for CABG (patients in the CABG/coronary artery disease group plus the CABG/coronary orifice group) versus those not planned for CABG (patients in non-cabg group plus the CABG/ bailout group), remained significant (3 of 282 patients, 1%; versus 18 of 87 patients, 20%; p 0.01). carditis, dissection) in 50 patients (14%). One hundred patients (27%) presented urgently or emergently, and 24 patients (7%) were in cardiogenic shock. Sixty-three patients (17%) had undergone previous cardiac surgery, and 48 patients (13%) had undergone previous valve surgery. Incisions and Myocardial Protection The majority of patients (308 patients, 83%) were approached by means of a full sternotomy, whereas 56 patients (15%) underwent upper hemisternotomy, 2 patients (0.5%) were approached through a right parasternal incision, and 3 patients (0.8%) through a right thoracotomy incision. Myocardial protection techniques, based on surgeon preference, were accomplished with topical and systemic hypothermia (median, 25 C; range, C), as well as 4:1 cardioplegia (CP), which was delivered antegrade only in 51 patients (14%), retrograde only in 17 patients (5%), and both antegrade and retrograde in 298 patients (81%). One patient (0.3%) did not receive CP and the myocardium was protected solely by systemic hypothermia. Concomitant Coronary Artery Bypass Grafting Patients undergoing concomitant CABG (95 patients, 26%) were divided into three subsets on the basis of the indication for coronary revascularization (Fig 1). The CAD group (73 patients, 20%; CABG/CAD group) included 66 patients with significant CAD, confirmed by preoperative coronary angiography, plus 7 patients who had known or suspected CAD that was not confirmed angiographically immediately before surgery owing to the urgent status of the procedure. In these 7 patients, revascularization was performed on the basis of inspection and palpation. In the CABG/CAD group, there were 21 of 73 patients (29%) who also had either active endocarditis or acute aortic dissection. Another 14 patients presented with active endocarditis or acute aortic dissection involving the coronary orifice(s) but had no significant CAD by angiography or palpation (14 patients, 4%; CABG/coronary orifice group). The need for CABG in these 14 patients was determined after inspection of the aortic valve, root and aortic sinuses, but before the root procedure. In both the CABG/CAD and CABG/coronary orifice groups (87 patients, 24%), an anatomic obstruction was present and known before commencing the root replacement procedure. Thus, the CABG procedure was planned in these 87 patients. In contrast to these patients, another 8 patients (2%) required CABG after completion of the root procedure secondary to ventricular dysfunction or bleeding from the coronary button(s) during weaning from bypass (CABG/bailout group). In these 8 patients, CABG was not deemed necessary until after the aortic root procedure was performed. These were patients with regional wall motion abnormalities and therefore suspected but unconfirmed CAD (n 3), or a torn or edematous right coronary artery ostium resulting in ventricular dysfunction or bleeding, requiring ligation of the right coronary artery ostia and placement of a CABG to the right coronary artery (n 5). Statistics Statistical analysis was performed using STATA 6.0 Intercooled (College Station, TX). The Fisher s exact test Table 1. Full Root Replacement Techniques (n 356) Technique No. of Patients (%) Reimplantation of both coronaries (n 326) Button technique Bentall/DeBono technique Cabrol technique 2 a 0.6 Ross (button technique) Button interposition of 1 SVG 8 2 Button Hemashield interposition Reimplantation of one coronary (n 22) Button technique for other 18 5 SVG interposition for other 4 1 No coronary reimplantation (n 8) No CABG performed 2 a 0.6 CABG instead of reimplantation 6 2 a Same 2 patients. CABG coronary artery bypass graft; SVG saphenous vein graft.

3 Ann Thorac Surg BYRNE ET AL 2005;79:511 6 CABG AND SURVIVAL AFTER AORTIC ROOT REPLACEMENT 513 and Mann-Whitney U test were used for the univariate analysis of dichotomous and continuous independent variables, respectively. Multivariate analysis was performed using logistic regression. Inclusion criterion was p less than or equal to 0.200; however, the clinical significance of each variable was taken into consideration before inclusion or exclusion from the multivariate analysis. The Appendix summarizes the variables used in the logistic regression analysis. All statistical analyses were performed at a level of 0.05, one-sided for mortality and myocardial infarction (MI) and two-sided for all other observations. The one-sided analysis was used for mortality and MI to avoid using variables that promoted survival or MI. Results Pathologic Findings and Implantation Techniques Pathologic findings were annuloaortic ectasia in 102 patients (28%), aortic valve calcification in 91 patients (25%), bicuspid or congenital deformation of the aortic valve (AV) in 61 patients (17%), active endocarditis in 44 patients (12%), and acute type A dissection in 40 patients (11%). Thirty-one patients (8%) had other pathologic findings. Thirty-one patients (8%) had the clinical manifestations of Marfan s syndrome, 1 patient (0.3%) had Ehlers-Danlos syndrome, and another 1 patient (0.3%) had hereditary telangiectasia. Two patients (0.5%) had findings consistent with cystic medial necrosis, and 1 patient (0.3%) had giant cell aortitis. Full root replacement was performed in 356 patients (96%) patients, hemiroot in 10 patients (3%), and valvesparing root replacement in 3 patients (0.8%). The Ross procedure was performed in 42 patients (11%), and 2 patients (0.5%) received a stented biologic valve sutured into a separate aortic tube graft. One hundred fifty-eight patients (43%) received a homograft, 28 patients (8%) received a Freestyle stentless xenograft, and 136 patients (37%) received a mechanical valved conduit. Aortic valve prosthesis diameter ranged between 19 and 31 mm (median, 24 mm). Of the 356 full root replacements, the button technique was used for both coronaries in 270 of 356 patients (76%), whereas in 86 of 356 patients (23%) deviations from this technique were required secondary to CAD or the inability to directly reimplant one or both coronary arteries (Table 1). The 2 patients in whom neither coronary button reimplantation nor CABG was performed are the same 2 patients as the 2 Cabrol technique patients. The use of mechanical valved conduits decreased in favor of homografts and stentless xenografts throughout the study period: mechanical conduits were used in 48% in the period between 1992 and 1996 versus 30% in the period between 1997 and 2001 (p 0.001). Concomitant Procedures Concomitant procedures included CABG in 95 patients (26%). One graft was performed in 51 patients (14%), two in 19 patients (5%), three in 17 patients (5%), four in 7 Table 2. Patient Characteristics With and Without Concomitant Coronary Artery Bypass Grafting Variable All Patients (n 369) Non-CABG (n 274) CABG (n 95) p Value Preoperative Age over 65 y 15% 55% Urgent/emergent 23% 40% NYHA III or IV 35% 52% EF % 9% 0.33 Reoperation 15% 24% 0.04 Nonsinus rhythm 7% 9% 0.36 Intraoperative Acute aortic dissection 7% 21% Active endocarditis 11% 16% 0.20 Arch aneurysm 7% 18% Concomitant MV 6% 7% 0.62 surgery CPB temperature 25 C 45% 67% CP antegrade only 15% 11% 0.39 CP retrograde or both 85% 88% 0.50 AoX 160 min 24% 43% CPB 220 min 23% 51% Circulatory arrest 13% 37% Aprotinin used 24% 22% 0.78 Postoperative Myocardial infarction 8% 30% Respiratory insufficiency 5% 17% Stroke 1% 13% Postoperative bleeding 9% 20% 0.01 Mortality 0.4% 21% AoX aortic cross-clamp; CABG coronary artery bypass grafting; CP cardioplegia; CPB cardiopulmonary bypass; EF ejection fraction; MV mitral valve; NYHA New York Heart Association. patients (2%), and five in 1 patient (0.3%). Six patients had previous saphenous vein grafts. These were mainly reattached with or without saphenous vein graft interposition, if the length was short. In 1 patient with occluded saphenous vein grafts, a new saphenous vein graft was performed. If the grafts were patent, the cardioplegia was delivered through the preexisting saphenous vein grafts. Other concomitant procedures included aortic arch replacement in 37 patients (10%), three of them with extension into the descending aorta, and mitral valve surgery in 24 patients (7%; 12 replacements, 8 repairs including ring annuloplasty, and 3 repairs without ring annuloplasty). Less common were anterior septal defect repair (4 patients, 1%), ventricular septal defect repair (4 patients, 1%), tricuspid valve repair (3 patients, 1%), pulmonary valve debridement (1 patient, 0.3%), and repair of a liver laceration secondary to preoperative cardiopulmonary resuscitation (1 patient, 0.3%). One patient (0.3%) required a Glenn shunt for right ventricular failure, which became apparent during weaning from cardiopulmonary bypass (CPB).

4 514 BYRNE ET AL Ann Thorac Surg CABG AND SURVIVAL AFTER AORTIC ROOT REPLACEMENT 2005;79:511 6 Table 3. Univariate Predictors of Operative Mortality in the Coronary Artery Bypass Grafting Group CABG Group (n 95) Survivors [%] (n 75) Deaths [%] (n 20) p Value Preoperative Age over 65 y NS Urgent/emergent NYHA III or IV EF NS Reoperation Nonsinus rhythm 8 15 NS Acute aortic dissection Active endocarditis Arch aneurysm NS Operative Concomitant MV 8 5 NS surgery CPB temperature 25 C Failure to use retrograde CP AoX 160 min NS CPB 220 min Circulatory arrest NS Aprotinin used NS Postoperative Myocardial infarction Respiratory insufficiency NS Stroke NS Reoperation for bleeding NS AoX aortic cross-clamp; CABG coronary artery bypass grafting; CP cardioplegia; CPB cardiopulmonary bypass; EF ejection fraction; MV mitral valve; NS not significant; NYHA New York Heart Association. Operative Characteristics Median CPB time was 181 minutes (range, 92 to 561 minutes), and in 111 patients (30%) it was longer than 220 minutes. Median aortic cross-clamp time was 137 minutes (range, 27 to 442 minutes), and in 104 patients (28%) it was longer than 160 minutes. Durations of CPB and aortic cross-clamping of 220 and 160 minutes, respectively, were chosen because they each represented the 75th percentile of those measurements for the entire cohort. Circulatory arrest was required in 71 patients (19%), and this ranged between 4 and 125 minutes (median, 29 minutes). In the majority of circulatory arrest patients, based on surgeon preference, cerebral protection consisted of systemic hypothermia and retrograde cerebral perfusion. There was no relationship between circulatory arrest and perioperative stroke. Aprotinin was used in 86 patients (23%). Operative Mortality Overall operative mortality (OM; defined as in-hospital death or death within 30 days of surgery) was 21 patients (5.7%). Etiology-specific OM rate varied: active endocarditis and acute dissection were associated with the highest OM rate. Thirteen of 21 patients (62%) died of myocardial failure, 2 of 21 patients (10%) after postoperative cardiac arrest, and 3 of 21 patients (14%) owing to multisystem organ failure. Other causes of death included hemorrhage (n 1), embolic stroke (n 1), and sepsis (n 1). The two groups of patients the CABG group (95 patients, 26%) and the non-cabg group (274 patients, 74%) were inhomogeneous in terms of preoperative (age, status) and intraoperative (associated arch aneurysms, temperature on CPB, route of CP, duration of aortic cross-clamping and CPB, and utilization of circulatory arrest) characteristics (Table 2). The OM rate for the non-cabg group was 0.4% (1 of 274 patients), whereas that for the CABG group was 21% (20 of 95 patients; p 0.001; Fig 1). The OM rate for the CABG/CAD group was 19% (14 of 73 patients), for the CABG/coronary orifice group, 29% (4 of 14 patients), and for the CABG/bailout group, 25% (2 of 8 patients). The OM rate in patients initially planned for CABG (CABG/ CAD group plus CABG/coronary orifice group) versus those not initially planned for CABG (non-cabg group plus CABG/bailout group) remained significant (3 of 282 patients, 1%, versus 18 of 87 patients, 20%; p 0.01). Because of the extremely low mortality rate in the non-cabg group (0.4%, n 1) as well as the entire cohort (5.7%, n 21), multivariate analysis for predictors of OM was performed only on the CABG group. Univariate analysis in the CABG group revealed associations with urgent procedures, New York Heart Association functional class III or IV (but not ejection fraction), reoperations, acute type aortic A dissection, active endocarditis, failure to use retrograde CP, CPB duration greater than 220 minutes, and perioperative MI (Table 3). In the CABG group, all patients who underwent surgery for active endocarditis or acute type A aortic dissection and who failed to receive retrograde cardioplegia (n 4 of 35 patients) died (OM rate, 100% versus 73%; p 0.03). Independent predictors of OM rate in the CABG group, identified by multivariate logistic regression, were New York Heart Association class III or IV, acute type A aortic dissection, active endocarditis, and failure to use retrograde CP (Table 4). Neither the presence of CABG/ coronary orifice anatomy nor the use of CABG/bailout procedure predicted OM rate. Perioperative Myocardial Infarction Perioperative MI was defined by the presence of new postoperative heart-specific creatine kinase values more Table 4. Multivariate Analysis for Operative Mortality in the Coronary Artery Bypass Grafting Group (n 95) Hospital Mortality P z Odds Ratio (95% CI) NYHA functional class III or IV ( ) Acute dissection ( ) Active endocarditis ( ) Failure to use retrograde CP ( ) CI confidence interval; CP cardioplegia; NYHA New York Heart Association.

5 Ann Thorac Surg BYRNE ET AL 2005;79:511 6 CABG AND SURVIVAL AFTER AORTIC ROOT REPLACEMENT 515 Table 5. Postoperative Complications in Survivors (n 348) Postoperative Complications No. of Patients (%) New atrial fibrillation Cardiac arrest (recovery) 10 3 Myocardial infarction (recovery) Low cardiac output syndrome 33 9 IABP/VAD 21/4 6/1 Implantation PPM/ICD 20/3 6/1 Early endocarditis CVA/TIA 13/1 4/0.3 Reoperation for bleeding Superficial/deep sternal wound 2/5 1/1 infection Bacteremia/sepsis 5 1 Renal failure/new postoperative 13/3 4/1 hemodialysis GI bleeding 2 1 Pancreatitis CVA cerebrovascular accident; GI gastrointestinal; IABP intraaortic balloon pump; ICD implantable cardiac defibrillator; PPM permanent cardiac pacemaker; TIA transient ischemic attack; VAD ventricular assist device. than 50 IU/L, electrocardiographic changes, or new wall motion abnormalities on echocardiogram. The perioperative MI rate for the entire cohort was 38 patients (11%). There was a significantly greater incidence of perioperative MI in the CABG group compared with the non- CABG group (28 of 95 patients, 30%; versus 22 of 274 patients, 8%; p 0.001; Table 2). Among the patients in the CABG group who sustained perioperative MI, 12 of 28 patients (43%) died (Table 3). The univariate analysis revealed that concomitant mitral valve surgery (3% versus 18%; p 0.02) and failure to use retrograde cardioplegia (6% versus 21%; p 0.04) were associated with perioperative MI. Additional postoperative complications are detailed in Table 5. No multivariate predictors of MI were identified. Comment When we previously evaluated the late results of isolated elective homograft aortic valve replacement [3] and when we compared the late results of elective biologic versus mechanical aortic root prostheses [4], both in smaller cohorts of the present series, we documented that isolated or elective aortic root replacement is an exceeding safe procedure. Those studies, however, addressed primarily late valve outcomes. In the present report, evaluating the entire cohort, we focused on the impact of concomitant CABG on early outcomes and the potential impact of risk-shifting. In our series, overall OM rate was 5.7%, and the majority of these deaths were attributed to cardiac causes, as previously reported [1, 2, 5 11]. Our non- CABG patients (n 274) revealed an OM rate of 0.4%, which was lower than the 3.6% to 4.3% mortality reported by the US registries for isolated aortic valve replacement [12, 13]. Conversely, our data, and those of previous studies [1, 2, 14], document that patients requiring concomitant CABG had significantly greater OM and perioperative morbidity rates, thus constituting a very high-risk group. Thus, the CABG group represents a multiple-morbidity, high-risk group in which the need for CABG represents a surrogate for multiple comorbidities. In this study, the CABG/bailout group included 8 patients who were not initially planned for CABG but in whom intraoperative complications arose from technical error in the coronary button anastomosis or regional myocardial dysfunction and suspected but unconfirmed CAD mandating blind use of CABG. Had CABG/ bailout been a more common occurrence, there is little doubt that its effect on our OM rate would have been more significant. Thus, this study, with only 8 patients in the CABG/bailout group, is underpowered to rule out type II error. Another important finding was that CABG/coronary orifice anatomy, that is the need to perform CABG because of destruction of the native coronary orifices owing to endocarditis or acute aortic dissection, was associated with very high OM rate (29%). In these patients, it is likely that acute myocardial ischemia is ongoing as a result of malperfusion of the coronary arteries. Had the CABG/coronary orifice anatomy been a more common occurrence, it too would have had a more profound influence on overall OM rate. In such patient with coronary malperfusion, myocardial protection becomes even more important. We have previously documented the importance of myocardial protection in aortic valve and root surgery [15, 16]. The present study showed that failure to use retrograde CP in the CABG group significantly increased the perioperative MI and OM rates. Significant CAD has already been shown to result in inhomogeneous and inadequate distribution of CP when delivered antegrade only [17, 18]. Our study documents that this is also important in patients with compromised coronary flow owing to acute aortic dissection or endocarditis involving the coronary arteries as well as in patients who require CABG as a result of technical error in the coronary button anastomosis or suspected but unconfirmed CAD. Although the protective effects of retrograde CP were seen only in the CABG group and cannot be extended to aortic root replacement in which concomitant CABG is not needed, our results indicate that retrograde CP should be strongly considered when CABG is anticipated. However, this strategy may help minimize the risks in patients in whom coronary angiography is unavailable before surgery owing to acute aortic dissection or active endocarditis. Perioperative MI was significantly more common in the CABG group (30% versus 8%), which helps explain why the MI rate for the entire cohort was 11%. When MI did occur, it was strongly associated with operative death: of the 28 patients in the CABG group who sustained MI, 12 patients (43%) died. In the univariate analysis, concomitant mitral valve surgery was associated with MI, but this could not be confirmed in the multivar-

6 516 BYRNE ET AL Ann Thorac Surg CABG AND SURVIVAL AFTER AORTIC ROOT REPLACEMENT 2005;79:511 6 iate analysis, probably because of the relative small number of patients. We do not believe any mitral valve patients sustained injury to the circumflex coronary artery, but this cannot be confirmed. The other predictors of mortality in our study (New York Heart Association class III or IV, acute aortic dissection, and active endocarditis) have been previously described [1, 2, 5 7, 9, 11], but these are less amenable to modification once the patient has presented to the operating room. References 1. Westaby S, Katsumata T, Vaccari G. Aortic root replacement with coronary button re-implantation: low risk and predictable outcome. Eur J Cardiothorac Surg 2000;17: Lytle BW, Mahfood SS, Cosgrove DM, Loop FD. Replacement of the ascending aorta. Early and late results. J Thorac Cardiovasc Surg 1990;99: Byrne JG, Karavas AN, Mihaljevic T, et al. Role of cryopreserved homograft in isolated elective aortic valve replacement. Am J Cardiol 2003;91: Byrne JG, Gudbjartsson T, Karavas AN, et al. Biological vs. mechanical aortic root replacement. Eur J Cardiothorac Surg 2003;23: Gott VL, Gillinov AM, Pyeritz RE, et al. Aortic root replacement. Risk factor analysis of a seventeen-year experience with 270 patients. J Thorac Cardiovasc Surg 1995;109: Mingke D, Dresler C, Stone CD, Borst HG. Composite graft replacement of the aortic root in 335 patients with aneurysm or dissection. Thorac Cardiovasc Surg 1998;46: Crawford ES, Svensson LG, Coselli JS, et al. Surgical treatment of aneurysm and/or dissection of the ascending aorta, transverse aortic arch, and ascending aorta and transverse aortic arch. Factors influencing survival in 717 patients. J Thorac Cardiovasc Surg 1989;98: Helseth HK, Haglin JJ, Monson BK, Wickstrom PH. Results of composite graft replacement for aortic root aneurysms. J Thorac Cardiovasc Surg 1980;80: Kouchoukos NT, Marshall WG Jr, Wedige-Stecher TA. Eleven-year experience with composite graft replacement of the ascending aorta and aortic valve. J Thorac Cardiovasc Surg 1986;92: Kouchoukos NT, Wareing TH, Murphy SF, Perrillo JB. Sixteen-year experience with aortic root replacement. Results of 172 operations. Ann Surg 1991;214: Raudkivi PJ, Williams JD, Monro JL, Ross JK. Surgical treatment of the ascending aorta. Fourteen years experience with 83 patients. J Thorac Cardiovasc Surg 1989;98: The Society of Thoracic Surgeons. STS National Database: Operative mortality by preoperative status and first vs. reoperation. US data 1997 aortic valve replacement. In: The Society of Thoracic Surgeons, 1998 ( 13. Astor BC, Kaczmarek RG, Hefflin B, Daley WR. Mortality after aortic valve replacement: results from a nationally representative database. Ann Thorac Surg 2000;70: Svensson LG, Crawford ES, Hess KR, et al. Composite valve graft replacement of the proximal aorta: comparison of techniques in 348 patients. Ann Thorac Surg 1992;54: Byrne JG, Adams DH, Couper GS, et al. Minimally-invasive aortic root replacement. Heart Surg Forum 1999;2: Byrne JG, Karavas AN, Cohn LH, Adams DH. Minimal access aortic root, valve, and complex ascending aortic surgery. Curr Cardiol Rep 2000;2: Allen BS, Winkelmann JW, Hanafy H, et al. Retrograde cardioplegia does not adequately perfuse the right ventricle. J Thorac Cardiovasc Surg 1995;109: Kaul TK, Fields BL, Wyatt DA, et al. Reoperative coronary artery bypass surgery: early and late results and management in 1300 patients. J Cardiovasc Surg (Torino) 1995;36: Appendix Variables Used for Predicting Hospital Mortality Active endocarditis Acute aortic dissection Age more than 65 years Aortic cross-clamp time 160 minutes Aprotinin used Arch aneurysm Coronary artery bypass grafting/bailout Coronary artery bypass grafting/coronary orifice Circulatory arrest Concomitant coronary artery bypass grafting (all subgroups) Concomitant mitral valve surgery Cardiopulmonary bypass temperature 25 C Cardiopulmonary bypass 220 minutes Cardioplegia antegrade only Cardioplegia Retrograde or Both Ejection fraction 0.35 Failure to use retrograde cardioplegia Myocardial infarction Nonsinus rhythm New York Heart Association functional class III or IV Postoperative bleeding Reoperation Respiratory insufficiency Reoperation for bleeding Stroke Urgent or emergent operation