Low-Flow, Low-Gradient Severe Aortic Stenosis in the Setting of Constrictive Pericarditis: Clinical Characteristics, Echocardiographic Features, and Outcomes.

BACKGROUND Low-flow, low-gradient aortic stenosis (AS), associated with a poor prognosis, can be caused by a reduced stroke volume despite a preserved ejection fraction (left ventricular ejection fraction). We hypothesized that impaired ventricular diastolic filling secondary to constrictive pericarditis (CP) could contribute to reduced transaortic gradients in patients with AS+CP. We sought to examine the characteristics and outcomes of this unique cohort. METHODS AND RESULTS We analyzed 84 patients with different degrees of AS and preserved left ventricular ejection fraction (≥50%): 28 diagnosed with concomitant CP by echocardiography and 56 patients without CP matched by age, sex, and AS severity during 1998 to 2013. Prior mediastinal radiation (32.1% versus 5.4%; P=0.0072) and cardiac surgery (50.0% versus 3.6%; P=0.0016) were more common in AS+CP patients than those with AS only. AS+CP patients had lower left ventricular stroke volume index and mean transaortic gradients. Five-year survival was 34.3% for AS+CP patients and 89.1% for those with AS only (P<0.001). In univariate analysis, prior mediastinal radiation (hazard ratio, 8.35; 95% confidence interval, 3.38-20.62; P<0.001), reduced left ventricular stroke volume index of <35 mL/m(2) (hazard ratio, 12.52; 95% confidence interval, 3.97-39.48; P<0.001), and concomitant CP (hazard ratio, 13.65; 95% confidence interval, 4.85-38.41; P<0.001) were highly associated with increased mortality. CONCLUSIONS Our findings highlighted the possibility of CP as a pathophysiological mechanism for low-flow, low-gradient AS. Left ventricular stroke volume index and transaortic gradients were commonly reduced in AS in the setting of CP despite a preserved left ventricular ejection fraction, which may result in underestimation of AS severity. Prior mediastinal radiation, lower left ventricular stroke volume index, and concomitant CP were associated with poorer survival in AS patients.