Should coronary artery bypass graft surgery patients with mild or moderate aortic stenosis undergo concomitant aortic valve replacement? A decision analysis approach to the surgical dilemma.
OBJECTIVE
This study utilizes Markov decision analysis to assess the relative benefits of prophylactic aortic valve replacement (AVR) at the time of coronary artery bypass graft surgery (CABG). Multiple sensitivity analyses were also performed to determine the variables that most profoundly affect outcome.


BACKGROUND
The decision to perform CABG or concomitant CABG and AVR (CABG/AVR) in asymptomatic patients who need CABG surgery but have mild to moderate aortic stenosis (AS) is not clear-cut.


METHODS
We performed Markov decision analysis comparing long-term, quality-adjusted life outcomes of patients with mild to moderate AS undergoing CABG versus CABG/AVR. Age-specific morbidity and mortality risks with CABG, CABG/AVR, and AVR after a prior CABG were based on the Society of Thoracic Surgeons national database (n = 1,344,100). Probabilities of progression to symptomatic AS, valve-related morbidity, and age-adjusted mortality rates were obtained from available published reports.


RESULTS
For average AS progression, the decision to replace the aortic valve at the time of elective CABG should be based on patient age and severity of AS measured by echocardiography. For patients under age 70 years, an AVR for mild AS is preferred if the peak valve gradient is >25 to 30 mm Hg. For older patients, the threshold increases by 1 to 2 mm Hg/year, so that an 85-year-old patient undergoing CABG should have AVR only if the gradient exceeds 50 mm Hg. The AS progression rate also influences outcomes. With slow progression (<3 mm Hg/year), CABG is favored for all patients with AS gradients <50 mm Hg; with rapid progression (>10 mm Hg/year), CABG/AVR is favored except for patients >80 years old with a valve gradient <25 mm Hg.


CONCLUSIONS
This study provides a decision aid for treating patients with mild to moderate AS requiring CABG surgery. Predictors of AS progression in individual patients need to be better defined.
Smith
William T
WT
Duke University Medical Center, Durham, North Carolina, USA.
Ferguson
T Bruce
TB
Ryan
Thomas
T
Landolfo
Carolyn K
CK
Peterson
Eric D
ED
D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000601:surgery*; D001024:Aortic Valve Stenosis / Q000601:surgery*; D001026:Coronary Artery Bypass; D018450:Disease Progression; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D008017:Life Expectancy; D008390:Markov Chains; D008875:Middle Aged; D011183:Postoperative Complications / Q000209:etiology / Q000401:mortality; D011788:Quality of Life; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D016019:Survival Analysis; D016896:Treatment Outcome