Gfo. Tyers et al., REOPERATION IN BIOLOGICAL AND MECHANICAL VALVE POPULATIONS - FATE OF THE REOPERATIVE PATIENT, The Annals of thoracic surgery, 60(2), 1995, pp. 464-469
From 1975 through 1992 inclusive, reoperative valve replacement (REOP)
was required by 12.9% of patients (708/5,499). Of 1,355 patients with
mechanical prostheses (MP), 46 (3.4%) came to REOP versus 662 of 4,14
4 patients (16%) with biological prostheses (BP). Early REOP mortality
rate was 17.4% (8/46) for MP and 10.6% (70/662) for BP (p = not signi
ficant). It was higher with age greater than 75 years (p < 0.05) and t
rended higher with concomitant procedures and with increasing number o
f REOPs (p = not significant). The percentage freedom from REOP at 5 a
nd 10 years for all BP was 96.0% +/- 0.4% and 74.9% +/- 1.1% compared
with 93.6% +/- 1.2% and 87.9% +/- 2.5% for MP. The most common cause o
f REOP in the BP patients was structural valve deterioration, which wa
s uncommon in patients with MP (72% versus 2% of REOP but only 15% ver
sus 0.1% of initial implants). Nonstructural dysfunction was the leadi
ng cause of REOP in the MP group (65% versus 11%). Prosthetic valve en
docarditis (18% versus 10%) and thromboembolic complications (10% vers
us 1%) were also more frequent causes of REOP in MP patients. However,
the increased relative role of these factors with MP is due to the mi
nimal incidence of structural valve deterioration. When related to the
original choice of MP versus BP, only thromboembolic complication (3.
8 times) was more prevalent as a cause of REOP in patients receiving M
P at their previous procedure (p = not significant). For patients who
previously received BP, structural valve deterioration (69 times) was
more likely to lead to REOP than with MP (p < 0.01). At REOP a patient
with MP is much more likely to get a second MP (85%) than a BP patien
t to get a second BP (58%). This study demonstrates a 1.9 times increa
se in REOP procedural risk with MP versus BP, but when related to init
ial/previous prosthesis selection, only 0.24%/pt-y (811,309) and 0.28%
/pt-y (70/3,482) patients died at REOP, no difference in risk if a BP
had been selected initially. The probability of REOP death was low reg
ardless of the type of prosthesis first implanted, and long-term resul
ts after REOP were generally excellent except in the previous MP to BP
replacement group. Selective prescription of MP versus BP based on ag
e, risk of systemic anticoagulation, lifestyle, and other individual f
eatures remains appropriate.