Quantitative Echocardiographic Determinants of Clinical Outcome in Asymptomatic Patients With Aortic Regurgitation : A Prospective Study

ObjectivesThe purpose of this study was to define the link between aortic regurgitation (AR) quantitation and clinical outcome in asymptomatic patients with AR.BackgroundQuantitative American Society of Echocardiography (QASE) thresholds are recommended for AR assessment, but impact on clinical outcome is unknown.MethodsWe prospectively enrolled (1991 to 2003) 251 asymptomatic patients (age 60 ± 17 years) with isolated AR and ejection fraction ≥50% with quantified AR and left ventricular (LV) volumes using Doppler-echocardiography.ResultsSurvival under medical management was independently determined by baseline regurgitant volume (RVol) (adjusted hazard ratio [HR] 1.22 [95% confidence interval (CI) 1.08 to 1.35] per 10 ml/beat, p = 0.002) and effective regurgitant orifice (ERO) (adjusted HR 1.52 [95% CI 1.19 to 1.91] per 10 mm2, p = 0.002), which superseded traditional AR grading. Patients with QASE-severe AR (RVol ≥60 ml/beat or ERO ≥30 mm2) versus QASE-mild AR (RVol <30 ml and ERO <10 mm2) had lower survival (10 years: 69 ± 9% vs. 92 ± 4%, p = 0.05) independently of all clinical characteristics (adjusted HR 4.1 [95% CI 1.4 to 14.1], p = 0.01) and lower survival free of surgery for AR (10 years: 20 ± 5% vs. 92 ± 4%, p < 0.001, adjusted HR 12.9 [95% CI 5.4 to 38.5]). Cardiac events were considerably more frequent with QASE-severe versus -moderate or -mild AR (10 years: 63 ± 8% vs. 34 ± 6% and 21 ± 8%, p < 0.0001). Independent determinants of cardiac events were quantitative AR grading (QASE-severe adjusted HR 5.2 [95% CI 2.2 to 14.8], p < 0.001; QASE-moderate adjusted HR 2.4 [95% CI 1.06 to 6.6], p = 0.035), which superseded traditional AR assessment (p < 0.001) and LV end-systolic volume index (ESVI) (adjusted HR 1.09 [95% CI 1.03 to 1.14 per 10 ml/m2], p = 0.002), which superseded LV M-mode diameters. In QASE-severe AR, patients with ESVI ≥45 versus <45 ml/m2 had higher cardiac event rates (10 years: 87 ± 8% vs. 40 ± 10%, p < 0.001). Cardiac surgery for AR reduced cardiac events in patients with QASE-severe AR (adjusted HR 0.23 [95% CI 0.09 to 0.57], p = 0.002).ConclusionsEchocardiographic quantitation of AR severity and ESVI provides independent and superior predictors of clinical outcome in asymptomatic patients with AR and ejection fraction ≥50% and should be widely clinically applied. Patients with QASE-severe AR and ESVI ≥45 ml/m2 should be carefully considered for cardiac surgery, which reduces cardiac events risk.