Postoperative lipid-lowering therapy and bioprosthesis structural valve deterioration: justification for a randomised trial?
OBJECTIVE
Bioprosthesis structural valve deterioration (SVD) is an incompletely understood process involving the accumulation of calcium and lipids. Whether this process could be delayed with lipid-lowering therapy (LLT) is currently unknown. The purpose of this observational study was to evaluate if an association exists between early LLT and a slowing of bioprosthesis SVD, with a view to designing a prospective trial.


METHODS
We followed 1193 patients who underwent aortic valve replacement with contemporary bioprostheses between 1990 and 2006 (mean follow-up 4.5+/-3.1 years, maximum 17.3 years). Of these patients, 150 received LLT (including statins) early after surgery. Prosthetic valve haemodynamics on echocardiography and freedom from re-operation for SVD were compared between patients who did and did not receive postoperative LLT.


RESULTS
After bioprosthetic implantation, the progression of peak and mean trans-prosthetic gradients during echocardiographic follow-up (mean 3.3 years) was equivalent between patients treated with and without LLT (peak increase: 0.9+/-7.7 vs 1.1+/-10.9 mmHg, LLT vs no LLT, P=0.87; mean increase: 0.8+/-4.1 vs 0.2+/-5.9 mmHg, LLT vs no LLT, P=0.38). The annualised linear rate of gradient progression following valve replacement was also similar between groups (peak increase per year: 2.0+/-12.1 vs 1.0+/-12.9 mmHg per year, LLT vs no LLT, P=0.52; mean increase per year: 0.5+/-2.2 vs 0.6+/-6.0 mmHg per year, LLT vs no LLT, P=0.94). The incidence of mild or greater aortic insufficiency on the most recent echocardiogram was comparable (16.3% vs 13.8%, LLT vs no LLT, P=0.44), and there was no difference in the 10-year freedom from re-operation for SVD between the two groups [98.9% (95% confidence interval (CI): 91.9%, 99.8%) vs 95.4% (95% CI 90.5%, 97.9%), LLT vs no LLT, P=0.72].


CONCLUSIONS
In this observational study, there was no association demonstrated between early postoperative LLT and a slowing of bioprosthesis SVD. With the excellent durability of bioprostheses in the current era, a prospective randomised trial of statin therapy to prevent bioprosthetic SVD does not appear to be justified, let alone feasible.
Kulik
Alexander
A
Division of Cardiac Surgery, University of Ottawa Heart Institute, Ottawa, ON, Canada.
Masters
Roy G
RG
Bédard
Pierre
P
Hendry
Paul J
PJ
Lam
B-Khanh
BK
Rubens
Fraser D
FD
Mesana
Thierry G
TG
Ruel
Marc
M
D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000601:surgery*; D001705:Bioprosthesis; D004812:Epidemiologic Methods; D005260:Female; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D000960:Hypolipidemic Agents / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011182:Postoperative Care / Q000379:methods; D011474:Prosthesis Design; D011475:Prosthesis Failure; D012086:Reoperation; D014463:Ultrasonography
D000960:Hypolipidemic Agents