Usefulness of aortic valve calcification in patients with low flow aortic stenosis

Abstract

ABSTRACTBackgroundAortic valve calcification (AVC) has been shown to be a powerful assessment of aortic stenosis severity (AS) and predictor of adverse outcome. However, its accuracy in patients with low-flow AS has not yet been proven.ObjectivesTo assess the predictive value of AVC in patients classical (CLF, i.e. low left ventricular ejection fraction [LVEF]) or paradoxical (PLF, i.e. low flow preserved LVEF) AS patients.MethodsWe prospectively include 641 patients, 319 (49.8%) with CLF-AS and 322 (50.2%) with PLF-AS who underwent Doppler-echocardiography and multidetector computed tomography. AVCratio was calculated as AVC divided by the sex-specific AVC threshold for AS-severity; AVC score ≥2,000 AU in males, and ≥1,200 AU in females. The primary endpoint of the study was all-cause mortality regardless of treatment.ResultsDuring a median follow-up of 4.9 (4.3-5.9) years there were 265 deaths. After comprehensive adjustment, AVCratio was associated with all-cause mortality in CLF-AS (aHR=1.25 [1.01-1.56]; p<0.05) and PLF-AS (aHR=1.51[1.14-2.00]; p=0.004) patients. There was an interaction (p=0.001) between AVC and AS flow pattern (i.e. CLF vs. PLF) with regard to the prediction of mortality. The best AVCratio threshold to predict mortality was different in CLF-AS (AVCratio≥0.7) and PLF-AS (AVCratio≥1) patients. After comprehensive analysis, AVCratio as a dichotomic variable was associated with all-cause mortality in all groups (p≤0.001). The addition of AVCratio to the models improved all model’s predictive value (all net reclassification index >18%; all p≤0.05).ConclusionIn patients with CLF or PLF AS, AVC is a major predictor of mortality. Thus, AVC should be used in low flow patients to stratify risk. Importantly, in patients with reduced LVEF, a non-severe AS (i.e. AVC 70% of severe) could be associated with reduce survival.Clinical PerspectiveWhat is new?Aortic valve calcification is a powerful predictor of outcome in patients with low ejection fraction aortic stenosis and in patients with low-flow despite normal ejection fraction aortic stenosis.In patient with low ejection fraction aortic stenosis, a non-severe calcification (AVCratio=0.7) is associated with increased mortality. An AVCratio of 0.7 correspond to an AVC of 840AU in female patients and 1,400AU in male patients.What are the clinical implications?AVC should be used in low ejection fraction and low flow patients to assess aortic stenosis severity and stratify risk.A severe AVC, in patient with low-flow preserved ejection fraction, could help in clinical decision making.A moderate-to-severe AVC (i.e. AVCratio>0.7), in patients with low ejection fraction, is detrimental and may be used to refine clinical decision making.