Original article: cardiovascular
Survival advantage of stentless aortic bioprostheses

Presented at the Thirty-sixth Annual meeting of The Society of Thoracic Surgeons, Ft. Lauderdale, FL, Jan 31–Feb 2, 2000.
https://doi.org/10.1016/S0003-4975(00)01736-7Get rights and content

Abstract

Background. Bioprostheses (BPs) are used to avoid anticoagulation after aortic valve replacement (AVR) in patients over 65 years of age. Stentless BPs offer established hemodynamic benefits. We sought to determine whether these advantages translate into improved survival.

Methods. Between 1993 and 1997, follow-up data (for Food and Drug Administration submission) were collected prospectively for 160 consecutive, unselected hospital survivors who received the Freestyle valve (FS). Equivalent data were collected for 247 Carpentier-Edwards (CE) porcine xenograft patients. Detailed comparative statistical analysis was used to compare events and survival between the groups. Follow-up was 100% complete for the FS (5.2 years maximum; mean 3.2 ± 1.0 years) group and 98% (7.2 years maximum; mean 3.8 ± 2.0 years) for CE.

Results. The groups were well matched in age (FS, 73 ± 6 years; CE, 74 ± 6 years), gender (FS, 58% male; CE, 62% male), ventricular function, and number of patients requiring coronary grafts (FS, 41%; CE, 37%). Actuarial survival at 5 years was 84% for FS versus 69% for CE (p = 0.023 Kaplan Meier, p = 0.009 Cox). Annual mortality rates were 3.6% for FS versus 7.1% for CE (p = 0.001). Thromboembolic rate was 0.8% per year for FS and 2.4% for CE (p = 0.024) without a difference in cardiac rhythm. Incidence of nonstructural dysfunction (paravalvular leak) was 0.2% for FS versus 1.3% for CE (p = 0.020).

Conclusions. By 5 years, the stentless valve patients had improved survival and reduced adverse events. Though differences in durability are yet to be proved, our findings support the use of stentless bioprostheses in this age group.

Section snippets

Patients and methods

The study aim was to determine differences in outcome between hospital survivors with stented and stentless bioprostheses. We investigated late postoperative morbid events and longevity in concurrent series of patients undergoing aortic valve replacement with the Freestyle stentless xenograft (FSV; Medtronic Inc, Minneapolis, MN) from July 1993 to June 1997, and the Carpentier-Edwards (CE) SAV bioprosthesis model 2650 (Baxter Health Care Inc, Irvine, CA) from January 1992 to February 1998. Both

Results

Analysis of preoperative data showed the FSV patients to be sicker (NYHA class III/IV, FSV 73%, CE 46%; p < 0.01) with a greater incidence of renal impairment (Creatinine > 140 mg/dL; FSV 36%, CE 18%; p < 0.01) (Table 1). This may reflect the cardiologists’ referral practice, because in every other respect the patients were closely matched. Sizes of prostheses implanted (reflecting annulus size) were also comparable (Table 2). There was no significant difference in operative mortality between

Limitations of the study

This was not a prospective randomized trial, but a comparative study, which describes the outcome in concurrent groups of hospital survivors who received a stented or stentless porcine xenograft at the same center. However, in contrast to the small number of randomized trials, our patients were not selected as favorable candidates for the stentless valve 9, 10. Paradoxically, sicker patients were referred to the surgeon who used stentless valves and could have biased survival against this

References (27)

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