Aortic Root Replacement With the Carboseal Composite Graft: 7-Year Experience With the First 100 Implants

Transcription

1 Aortic Root Replacement With the Carboseal Composite Graft: 7-Year Experience With the First 100 Implants Giovanni Battista Luciani, MD, Gianluca Casali, MD, Luca Barozzi, MD, and Alessandro Mazzucco, MD Division of Cardiac Surgery, University of Verona, Verona, Italy Background. Aortic root replacement remains a challenging surgical procedure. A variety of techniques and prosthetic devices have thus far been used. In order to assess the performance of the Carboseal (Sultzer Carbomedics, Inc, Austin TX) composite graft, review of the experience with composite root replacement was undertaken. Methods. Between January 1979 and December 1998, 273 patients underwent composite aortic root replacement. One-hundred-six received the Carboseal composite prosthesis (group 1) and 84 other types of composite grafts (group 2). Demographic and operative variables were similar in the 2 patient groups, except for an older mean age in group 1 (58 12 versus years, p 0.001). Results. Operative mortality was lower in group 1 patients (3 of 106, 3% versus 10 of 84, 12%, p 0.04). Follow-up of survivors was longer in group 2 due to more recent adoption of the Carboseal grafts (93 57 versus months, p 0.01). Late mortality was higher in group 2 (3 of 103, 3% versus 13 of 74, 18%, p 0.04), with higher prevalence of prosthetic-related complications (2 of 103, 2% versus 12 of 74, 15%, p 0.002). Reoperation was more prevalent in group 2 (1 of 103, 1% versus 5 of 74, 8%, p 0.04), and limited to patients having root replacement using the inclusion technique. Functional status of survivors was comparable in the 2 groups (83 of 103, 80% versus 45 of 74, 61% of patients in New York Heart Association class I, p 0.1). Conclusions. Aortic root replacement using the Carboseal composite graft offers excellent long-term results, with negligible prevalence of prosthetic-related complications. Superior performance compared to other available composite grafts in the present series may be influenced by more recent adoption of the Carboseal conduit and concomitant uniform adoption of coronary button technique. (Ann Thorac Surg 1999;68: ) 1999 by The Society of Thoracic Surgeons Since the original description by Bentall and DeBono [1], aortic root replacement (ARR) has undergone substantial evolution over the last three decades in terms of clinical indications, operative techniques, and available prosthetic substitutes. Not surprisingly, elective root replacement can now be performed with an operative risk that is not significantly higher than the risk of isolated aortic valve replacement [2 6]. While extensive clinical data have been collected to support the relative advantages of currently adopted surgical techniques for aortic root replacement [3, 4, 6 10], scant information is available on the performance of different prosthetic devices used for root replacement [11]. The purpose of the present study was to assess the clinical results of aortic root replacement using the Carboseal (Sulzer Carbomedics, Inc, Austin, TX) composite graft. A retrospective comparison with the experience using other available prosthetic devices was also undertaken. Accepted for publication June 3, Address reprint requests to Dr Luciani, Division of Cardiac Surgery, University of Verona, O.C.M. Piazzale Stefani 1, Verona, Italy; luciani@netbusiness.it. Material and Methods Between January 1979 and December 1998, 273 patients underwent aortic root replacement at the University of Verona. Eighty-three patients received a biological graft (autograft, homograft, xenograft) as a substitute of the native aortic root, and were thus excluded from the present review. The remaining 190 patients had composite root replacement using a variety of currently available prosthetic devices. The type of prosthetic device and the relative distribution over time are depicted in Figure 1. Adoption of the Bjork-Shiley (Shiley Inc, Irvine, CA), Sorin (Sorin Biomedica, Inc, Saluggia, Italy), and other composite grafts predated use of the Carboseal prosthesis, which was routinely employed only after release in the European market in The Carboseal graft is a composite valve conduit which incorporates the Carbomedics aortic valve (Sulzer Carbomedics) in a gelatinimpregnated, woven Dacron tube graft. For the purpose of comparison, all patients having composite root replacement were retrospectively assigned to either 1 of 2 groups: group 1 patients received the Carboseal graft and group 2 patients received other types of Comparison of demographic variables disclosed a higher 1999 by The Society of Thoracic Surgeons /99/$20.00 Published by Elsevier Science Inc PII S (99)01111-X

2 Ann Thorac Surg BATTISTA ET AL 1999;68: ROOT REPLACEMENT WITH CARBOSEAL CONDUIT 2259 Fig 1. Histogram showing the number and types of prosthetic aortic root substitutes used for composite root replacement at the University of Verona between January 1979 and December mean age in group 1, the other parameters being similar (Table 1). Younger mean age in group 2 may be explained by more recent adoption of autografts and homografts, as opposed to composite grafts, for children and adolescents needing aortic root replacement, as reported elsewhere [12]. No difference in terms of operative variables was appreciated between the two groups (Table 2). The technique used for aortic root replacement consisted of routine inclusion of the graft between 1979 and 1990, which was performed alternatively as the standard Bentall, in 22 patients, or the Cabrol, operation, in 16. Beginning with 1990, the coronary button technique, entailing complete resection of all diseased aortic wall and mobilization of the coronary ostia, was introduced and rapidly became the standard method to perform the operation [10]. Accordingly, only 17 additional patients had root replacement using the standard Bentall technique between 1990 and Thereafter, all operations were performed using the coronary button technique. All composite valve conduits were implanted using moderately hypothermic cardiopulmonary bypass during a period of myocardial ischemia (Table 2). Distal anastomoses were performed using the open technique during a period of deep hypothermic circulatory arrest in all cases of acute type A dissection or when concomitant arch replacement was required. Prior to 1994, myocardial protection consisted of cold crystalloid cardioplegia induction and maintenance. Beginning with 1994, cold blood cardioplegia using both antegrade and retrograde administration was routinely adopted. Composite grafts were inserted using extraanular, interrupted, pledgeted 2-0 Ticron (Ethicon, Sommerville, NJ) sutures. Coronary Table 1. Clinical Data Variable Group 1 Group 2 p n Age (yrs) Sex (% male) 82% 74% 0.09 Aortic dissection (% patients) 33% 37% 0.5 Emergency operation (% patients) 19% 15% 0.6 Prior aortic procedures (% patients) 13% 10% 0.5 anastomoses were completed using running 5-0 Prolene (Ethicon) sutures, while distal aortic anastomosis were completed using running 4-0 Prolene suture. Follow-up of hospital survivors was last collected between December 1998 and January 1999, and was 100% complete. Data were expressed as mean standard deviation, or as percentage. Comparison of continuous variables was done using the two-tailed Student s t test for unpaired data and the Pearson 2 test for categorical variables. Actuarial survival curves were constructed using the Kaplan-Meier product limit method and compared using the log-rank test. A p value of 0.05 or less was considered significant. Results Operative mortality was higher in group 2 patients (3 of 106, 3% versus 10 of 84, 12%, p 0.04). Comparison of causes of early casualty, however, disclosed similar prevalence of cardiac deaths due to progressive low output syndrome (3 of 3, 100% versus 8 of 12, 75%, p not significant). Other causes of early mortality in group 2 were perioperative hemorrhage in 2 patients, pulmonary embolism, and cardiac tamponade, each in 1 patient. When early mortality was related to indication to operation, it resulted significantly higher after emergent ARR (7 of 157, 4%, elective, versus 6 of 33, 18%, emergent operation, p 0.005). Follow-up of survivors ranged 1 to 220 months, mean months. Duration of follow-up was significantly shorter in group 1, due to more recent adoption of the Carboseal composite graft as reported Table 2. Operative Data Variable Group 1 Group 2 p n Aortic cross-clamp time (min) Bypass time (min) Associated procedures (% patients) 20% 14% 0.3 CABG 10% 6% Aortic arch replacement 7% 5% Mitral valve procedure 3% 3% CABG coronary artery bypass graft.

3 2260 BATTISTA ET AL Ann Thorac Surg ROOT REPLACEMENT WITH CARBOSEAL CONDUIT 1999;68: Fig 2. Actuarial survival after aortic root replacement with composite grafts: group 1, patients receiving the Carboseal composite graft; group 2, patients receiving other types of above (93 57 versus months, p 0.01). Late mortality was higher in group 2 patients (3 of 103, 3% versus 13 of 74, 18%, p 0.04). Cardiac events were responsible for most casualties in both groups, although these were significantly more common in group 1 (3 of 3, 100% versus 7 of 13, 54%, p 0.03). On the contrary, valve-related complications (2 cases of endocarditis, 2 of hemorrhage, and 1 of thromboembolism) accounted for most of the remaining 6 casualties in group 2. Due to lower early and late mortality, actuarial survival was significantly better in group 1 (93 5% versus 72 12% at 6 years, p 0.04) (Fig 2). Overall prevalence of prosthesis-related adverse events was also significantly lower in group 1 patients (2 of 103, 2% versus 12 of 74, 16%, p 0.002), although it did not translate into a worse valve-related event-free survival for group 2 patients, possibly due to shorter follow-up in group 1 (97 2% versus 92 6% at 6 years, p not significant). Device-related complications in patients having the Carboseal graft consisted of one episode of bleeding and one of reintervention, both occurring 2 years after the original operation. No instances of either thromboembolism or endocarditis were registered in this patient group at follow-up. Actuarial freedom from hemorrhage, from thromboembolism, and from endocarditis were comparable in the two patient groups (Figs 3 5). Reoperation was required in 6 of 177 (3%) operative survivors. The indication for reoperation was late development of pseudoaneurysm in 1 group 1 patient and in 5 group 2 patients, and new aortic dissection in 1 group 2 patient. Prevalence of reoperation was lower in group 1 (1 of 103, 1% versus 5/74, 7%, p 0.04). Actuarial freedom from reoperation resulted comparable in the 2 groups, as most reinterventions in group 2 were required 8 years or later after the original procedure (Fig 6). Analysis of prevalence of reoperation relative to surgical technique showed all reinterventions to be confined to patients having ARR using the inclusion method (6 of 48, 13% versus 0 of 129, 0%, p 0.001). Functional outcome was Fig 3. Actuarial freedom from hemorrhagic events after aortic root replacement with composite grafts: group 1, patients receiving the Carboseal composite graft; group 2, patients receiving other types of generally rewarding and similar in the 2 groups, with most patients in New York Heart Association class 1 at follow-up (75 of 100, 75% versus 43 of 71, 61%, p not significant). Comment Clinical outcome after ARR has greatly improved over the last three decades. Progress in preoperative and postoperative patient management, in conduct of cardiopulmonary bypass and myocardial protection, and in techniques and materials used for root replacement must be credited for the low mortality and morbidity of elective procedures in the current era [2 10]. Several works have attempted to ascertain the influence, if any, of the different operative techniques on early and late outcome after ARR [3, 4, 6 10]. Regardless of the method used for Fig 4. Actuarial freedom from thromboembolic events after aortic root replacement with composite grafts: group 1, patients receiving the Carboseal composite graft; group 2, patients receiving other types of

4 Ann Thorac Surg BATTISTA ET AL 1999;68: ROOT REPLACEMENT WITH CARBOSEAL CONDUIT 2261 Fig 5. Actuarial freedom from endocarditis after aortic root replacement with composite grafts: group 1, patients receiving the Carboseal composite graft; group 2, patients receiving other types of connection of the coronary ostia to the composite graft, a trend toward adoption of open techniques, which avoid inclusion of the conduit within the diseased aortic wall, has gradually emerged [3, 6, 8 10]. The observed higher prevalence of false aneurysm formation late after ARR with the inclusion technique is the strongest argument in favor of the above mentioned practice [3], although controlled studies resolving this controversy are by and large lacking. On the contrary, few reports have thus far focused on the impact, if any, of the different materials used for ARR [11]. Goal of the present review is to define the late results of root replacement using the Carboseal composite graft. The Carboseal conduit was first released for clinical use in the European market in 1992 and has since been used at our institution for ARR. Approval by the Federal Drug Administration was obtained only in The Fig 6. Actuarial freedom from reoperation after aortic root replacement with composite grafts: group 1, patients receiving the Carboseal composite graft; group 2, patients receiving other types of present review thus has the unique prerogative of combining a large number of graft implants with possibly the longest follow-up available of the device. Among the theoretical advantages of the Carboseal graft are the hemostatic and handling characteristics conferred by the gelatin-impregnated, double velour, woven Dacron vascular graft, associated with the reliability of the Carbomedics bileaflet prosthesis, which has thus far offered excellent long-term performance [13]. Analysis of the 7-year experience, with over 100 implants of the Carboseal graft, supports continued use of this conduit. Operative mortality after ARR using the Carboseal conduit is lower than with other prostheses and absolutely comparable to other clinical series [3 6, 8, 9, 11]. Although the influence of evolution of techniques for ARR and of patient management cannot be easily accounted for in our series, the observation that no early death in patients having ARR using the Carboseal graft was due to hemorrhage (as opposed to 2 of 10 in patients having other conduits), acute myocardial infarction, endocarditis, or thromboembolism may be of significance. Indeed, the negligible prevalence of perioperative lethal morbid events argues in favor of satisfactory hemostasis and pliability properties of the conduit, and low thrombogenicity of the valve. In addition, an operative mortality of 2.8% in the current series favorably compares even with the recently reported estimate of 4.4% for isolated aortic valve replacement using the Carbomedics prosthesis by Fiane and coworkers [13]. The rate of late complications using the Carboseal graft also seems lower when compared to other available conduits. Although longer follow-up of the Carboseal graft is required to conclude on its superiority over existing composite prostheses, this observation is less likely the result of improvements in operative techniques and patient management, and strongly suggests excellent biocompatibility of both the valve and the vascular graft. Indeed, a valve-related event-free survival of 97% 2% at six years represents an eloquent outcome and well correlates with the reported valve-related event-free survival of 92% 1% at 5 years for isolated aortic valve replacement with the Carbomedics prosthesis [13]. The low propensity of the conduit toward infective and thromboembolic complications, none in our patient population, make its use particularly attractive even in young adults. Lastly, prevalence of reoperation seems negligible late after ARR using the Carboseal composite graft. Although use of other types of conduits appear to be more frequently associated with the need for reintervention, the discrepancy in outcome, compared to patients having other types of conduits in our series, can be justified by the routine adoption of the coronary button technique after In fact, all reoperations were limited to patients having root replacement with the inclusion technique, as previously reported by us and others [3, 10]. Due to the more recent adoption of the Carboseal composite graft, and the concurrent evolution of surgical management of aortic root disease, no clear influence of the type of prosthetic conduit used for ARR can be detected from the present series. Aside from the retro-

5 2262 BATTISTA ET AL Ann Thorac Surg ROOT REPLACEMENT WITH CARBOSEAL CONDUIT 1999;68: spective and nonrandomized nature of the study, in fact, use of other conduits was more prevalent at early stages of our practice. Comparison of results of the 2 patient groups is thus merely indicative. Nevertheless, based on our 7-year long experience using the Carboseal graft, several preliminary conclusions can be drawn. Indeed, similar to the outcome described with the St. Jude/ Hemashield composite graft [11], the Carboseal conduit combines an easy implantation with favorable hemodynamic and hemostatic properties, thereby favoring a very low-risk elective root replacement operation. In addition, long-term behavior of the graft is excellent and, when using the coronary button technique, offers durable freedom from valve-related complications, including reoperation, which favorably compares to any other available conduit and substantially overlaps with the results obtained after isolated aortic valve replacement. References 1. Bentall HH, DeBono A. A technique for complete replacement of the ascending aorta. Thorax 1968;23: Kouchoukos NT, Marshall WG, Wedige-Stecker TA. Elevenyear 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. Ann Surg 1991;214: Svensson LG, Crawford ES, Hess KR, Coselli JS, Safi HJ. Composite valve graft replacement of the proximal aorta: comparison of techniques in 348 patients. Ann Thorac Surg 1992;54: Lewis CTP, Cooley DA, Murphy MC, Talledo O, Vega D. Surgical repair of aortic root aneurysm in 280 patients. Ann Thorac Surg 1992;53: 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: Cabrol C, Pavie A, Mesnildrey P, et al. Long-term results with total replacement of the ascending aorta and reimplantation of the coronary arteries. J Thorac Cardiovasc Surg 1986;91: Hilgenberg AD, Akins CW, Logan DL, et al. Composite aortic root replacement with direct coronary artery implantation. Ann Thorac Surg 1996;62: Bachet J, Termignon JL, Goudot B, et al. Aortic root replacement with a composite graft. Factors influencing immediate and long-term results. Eur J Cardiothorac Surg 1996;10: Luciani GB, Casali G, Pugliese P, Mazzucco A. Impact of surgical technique on long-term outcome after aortic root replacement. Proceedings of the 2nd International Congress of Thorax Surgery, June 24 27, 1998, Bologna, Italy. Editrice Compositori 1998; Girardi LN, Talwalkar NG, Coselli JS. Aortic root replacement: results using the St. Jude/Hemashield composite graft. Ann Thorac Surg 1997;64: Luciani GB, Casali G, Santini F, Mazzucco A. Aortic root replacement in adolescents and young adults: composite graft versus homograft and autograft. Ann Thorac Surg 1998;66:S Fiane AE, Geiran OR, Svennevig JL. Up to eight years follow-up of 997 patients receiving the CarboMedics prosthetic heart valve. Ann Thorac Surg 1998;66:443 8.