Aortic Valve Replacement in Moderate or Severe Aortic Stenosis Plus LV Dysfunction
Among patients with moderate or severe aortic stenosis (AS) and left ventricular (LV) systolic dysfunction, what is the frequency and the impact on survival of aortic valve replacement (AVR) with or without coronary artery bypass grafting (CABG)?
The Duke Echocardiographic Database (n = 132,804) was queried for patients with mean gradient ≥25 mm Hg and/or peak velocity ≥3 m/s and LV systolic dysfunction (LV ejection fraction ≤50%) from January 1995 through February 2014. AS was defined both by mean gradient and calculated aortic valve area (AVA). Time-dependent indicators of AVR in multivariable Cox models were used to assess the relationship between AVR and all-cause mortality.
A total of 1,634 patients had moderate (n = 1,090 [67%]) or severe (n = 544 [33%]) AS based on mean gradient. Overall, 287 (26%) patients with moderate AS and 263 (48%) patients with severe AS underwent AVR within 5 years of the qualifying echo. There were 863 (53%) deaths observed up to 5 years following the index echocardiogram. After multivariable adjustment in an inverse probability weighted regression model, AVR was associated with higher 5-year survival among patients with moderate AS and severe AS, whether classified by AVA or by mean gradient. Overall, AVR plus CABG compared with medical therapy was associated with significantly lower mortality (hazard ratio [HR], 0.49; [0.38-0.62], p < 0.0001). Compared with CABG alone, CABG plus AVR was associated with better survival (HR, 0.18 [0.12-0.27], p < 0.0001).
Among patients with moderate or severe AS and LV systolic dysfunction, mortality is substantial; among those who undergo surgery, AVR with or without CABG is associated with higher survival. The authors concluded that additional research is required to understand factors contributing to current practice patterns and the possible utility of transcatheter approaches in this high-risk cohort.
There are important clinical interactions between AS and LV systolic dysfunction (valvular AS obviates the effectiveness if not the feasibility of medical afterload-reducing therapy), and between AS and coronary artery disease (is AS not the most proximal coronary stenosis?). This study appears to provide support for AVR ± CABG among patients with moderate or severe AS and concomitant LV systolic dysfunction. In the setting of a retrospective study, questions remain regarding the ability to statistically compensate for differences between groups (some patients with severe AS and LV systolic dysfunction, a Class I guideline indication for AVR, did not undergo AVR; and many patients with moderate AS who underwent AVR had another indication for surgical intervention). As the authors note, additional data are needed before concluding that (surgical or transcatheter) intervention is appropriate among patients with truly moderate AS.
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