LV Strain in Chronic Severe Aortic Regurgitation
What is the prognostic utility of left ventricular (LV) global longitudinal strain (GLS) in asymptomatic patients with ≥III+ aortic regurgitation (AR), an indexed LV end-systolic dimension of <2.5 cm/m2, and preserved LV ejection fraction (LVEF)?
The investigators studied 1,063 such patients (53 ± 16 years; 77% men) seen between 2003 and 2010 (excluding those with symptoms, obstructive coronary artery disease, acute AR/dissection, aortic/mitral stenosis, more than moderate mitral regurgitation, and previous cardiac surgery). Society of Thoracic Surgeons (STS) score was calculated. The primary endpoint was mortality. Average resting LV-GLS was measured offline on two-, three-, and four-chamber views using Velocity Vector Imaging (Siemens, Malvern, PA).
The mean STS score, LVEF, LV-GLS, and right ventricular (RV) systolic pressure were 4.4 ± 5.0%, 57.0 ± 4.0%, -19.5 ± 0.2%, and 31.0 ± 9.0 mm Hg, respectively. In total, 671 patients (63%) underwent aortic valve surgery at a median of 42 days after the initial evaluation. At 6.8 ± 3.0 years, 146 patients (14%) had died. On multivariable Cox survival analysis, LV-GLS (hazard ratio [HR], 1.11), STS score (HR, 1.51), indexed LV end-systolic dimension (HR, 0.50), RV systolic pressure (HR, 1.33), and aortic valve surgery (HR, 0.35) were associated with longer-term mortality (all p < 0.001). Sequential addition of LV-GLS and aortic valve surgery improved the C-statistic for longer-term mortality for the clinical model (STS score + RV systolic pressure + indexed LV end-systolic dimension) from 0.61 (95% confidence interval [CI], 0.51-0.72) to 0.67 (95% CI, 0.54-0.87) and to 0.77 (95% CI, 0.63-0.90), respectively (p < 0.001 for both). A significantly higher proportion (log-rank p = 0.01) of patients with LV-GLS worse than median (-19.5%) died versus those with an LV-GLS better than median (86 of 513 [17%] vs. 60 of 550 [11%]). The risk of death at 5 years significantly increased with an LV-GLS of worse than -19%.
The authors concluded that in asymptomatic patients with ≥III+ chronic AR and preserved LVEF, worsening LV-GLS was associated with longer-term mortality.
This retrospective, observational study from a tertiary referral center reports that among asymptomatic patients with ≥III+ chronic AR, indexed LV end-systolic dimensions <2.5 cm/m2, and LVEF >50%, worsening LV-GLS was associated independently with longer-term mortality. These data suggest that sensitive indices of regional LV dysfunction like LV global longitudinal strain may have value in identifying a subset of AR patients where surgical intervention earlier than conventionally recommended may lead to improved long-term survival. It should be noted that given the design limitations of the study, the current data should be considered hypothesis generating and additional prospective, multicenter validation is indicated.
Clinical Topics: Cardiac Surgery, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Noninvasive Imaging, Valvular Heart Disease, Aortic Surgery, Cardiac Surgery and Heart Failure, Cardiac Surgery and VHD, Acute Heart Failure, Interventions and Coronary Artery Disease, Interventions and Imaging, Interventions and Structural Heart Disease, Mitral Regurgitation
Keywords: Aortic Valve Insufficiency, Aortic Valve Stenosis, Blood Pressure, Cardiac Imaging Techniques, Cardiac Surgical Procedures, Coronary Artery Disease, Heart Failure, Heart Valve Diseases, Mitral Valve Insufficiency, Mitral Valve Stenosis, Stroke Volume, Tertiary Care Centers, Ventricular Dysfunction, Left, Ventricular Function, Left
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