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Echo Systolic Volume and EF in Chronic Aortic Regurgitation
Quick Takes
- Among asymptomatic patients with significant chronic AR, LVESVi and volume-based LVEF worked equally as well as LVESDi and “linear” LVEF in discriminating risk for excess mortality.
- Thresholds associated with increased all-cause mortality included LVEF <60%, LVESDi >21-22 mm/m2, and LVESVi >40-45 ml/m2.
Study Questions:
Are echocardiographically derived left ventricular (LV) volumes and volume-derived LV ejection fraction (LVEF) associated with mortality among asymptomatic patients with chronic aortic regurgitation (AR)?
Methods:
Data from consecutive asymptomatic patients with chronic moderately severe or severe AR who underwent transthoracic echocardiography at a single high-volume referral center between January 2004 and April 2019, and who underwent cardiology and/or cardiac surgical evaluation within 30 days of the echocardiogram, were extracted from an echocardiography database. LV volumes were reassessed for this study using biplane apical images unless only a single plane was suitable. Patients were excluded from analysis if aortic valve surgery was performed within 2 months of the echocardiogram, or if surgery was performed for aortic aneurysm. The primary endpoint was all-cause mortality without surgical intervention; and the secondary endpoints were all-cause death during the entire follow-up, aortic valve surgery, and death or aortic valve surgery. LV end-systolic diameter index (LVESDi) and LV end-systolic volume index (LVESVi) were tested using previously defined thresholds (respectively 20 mm/m2 and 45 ml/m2), along with a methodologically undefined “linear” LVEF.
Results:
Of 492 asymptomatic patients (mean age 60 ± 17 years, 425 men [86%]), the prevalence of ischemic heart disease was low (41 patients [9%]), and 453 (92.1%) had preserved “linear” LVEF (≥50%) with mean LVESVi 41 ± 15 ml/m2. At a median (interquartile range) of 5.4 (2.5-10.1) years, 66 patients (13.4%) died under medical surveillance; overall survival was not different than the age- and sex-matched general population (p = 0.55). Separate multivariate models, adjusted for age, sex, Charlson Comorbidity Index, and AR severity, demonstrated that in addition to “linear” LVEF and LVESDi, LVESVi and volume-based LVEF were independently associated with mortality for patients who did not undergo surgery (all p < 0.05) with similar C-statistics (range 0.83-0.84). Spline curves showed that continuous risks of death started to rise for both “linear” LVEF and volume-based LVEF <60%, LVESVi >40-45 ml/m2, and LVESDi >21-22 mm/m2. As dichotomized variables, patients with LVESVi >45 ml/m2 exhibited increased relative death risk (hazard ratio, 1.93; 95% confidence interval, 1.10-3.38; p = 0.02), while LVESDi >20 mm/m2 did not (p = 0.32). LVESVi >45 ml/m2 was associated with a decreased survival trend compared with expected population survival.
Conclusions:
In this large cohort of asymptomatic patients with hemodynamically significant AR, LVESVi and volume-based LVEF worked equally as well as LVESDi and “linear” LVEF in discriminating risk for excess mortality. LVESVi ≥45 ml/m2 was significantly associated with an increased mortality risk.
Perspective:
There are accumulating data to suggest that conventional thresholds for surgical intervention for asymptomatic patients with chronic severe AR (including LVESDi >25 mm/m2 and LVEF <50%) are too high, leading to excess mortality compared to intervention at a lower level of LV enlargement or reduction in LVEF. This study showed that transthoracic echocardiographically derived LVEF <60%, LVESDi >21-22 mm/m2, or LVESVi >40-45 ml/m2 were associated with increased risks of all-cause mortality. This study adds additional weight to the concept of reassessing the thresholds for intervention for asymptomatic patients with chronic AR.
Clinical Topics: Cardiac Surgery, Geriatric Cardiology, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Valvular Heart Disease, Aortic Surgery, Cardiac Surgery and VHD, Interventions and Imaging, Interventions and Structural Heart Disease, Echocardiography/Ultrasound
Keywords: Aortic Valve Insufficiency, Cardiac Surgical Procedures, Comorbidity, Diagnostic Imaging, Echocardiography, Geriatrics, Heart Valve Diseases, Hypertrophy, Left Ventricular, Myocardial Ischemia, Stroke Volume
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