The CarboMedics 'Top-Hat' aortic valve prosthesis: short-term results

The CarboMedics 'Top-Hat' aortic valve prosthesis has been specifically designed for supra-annular implantation. The aim of this study was to assess the safety of implantation of this prosthesis by reporting the short-term results of follow up.

Between May 1993 and May 1998, 128 patients (mean age 62.5 +/- 9.8 years; range: 22-76 years) received a CarboMedics 'Top-Hat' prosthesis at our institution. Among patients, 55% were in NYHA functional classes III or IV, and 54.7% had an isolated aortic valve replacement. Associated procedures were: coronary artery bypass grafting (25.7%), double valve replacement (17.1%), treatment of ascending aortic aneurysm (4.7%) and miscellaneous (5.5%). Follow up was 100% complete; total cumulative follow up was 265 patient-years (pt-yr) (range: 2-60 months).

The overall mortality rate was 1.5% (two deaths). The operative mortality rate was 0.8% (one death); this patient died from neurological complications after operation for aortic dissection. The other patient died on postoperative day 40 from a massive cerebral hemorrhage. Four patients presented thromboembolic events; in all cases these were reversible ischemic neurologic deficits. One patient had a nonstructural deterioration (endocarditis) and required reoperation. Freedom from mortality was 98.3% at five years (linearized rate of 0.75%/pt-yr). Freedom from thromboembolism was 63.1% at five years (linearized rate 1.5%/pt-yr).

Short-term results with the CarboMedics 'Top-Hat' prosthesis were satisfactory, with low rates of morbidity and mortality. As this prosthesis has demonstrated a good reliability to date, we have continued its implantation in our institution, and long-term follow up will be necessary to confirm these good early results.