Prognostic value of left ventricular‐arterial coupling estimated using echocardiography in dogs with myxomatous mitral valve disease. (6th November 2021) - Osuga, Tatsuyuki
Abstract: Background: The interaction between the left ventricle (LV) and systemic arterial systems, known as left ventricular‐arterial coupling (VAC), has been evaluated based on the effective arterial elastance (Ea) to LV end‐systolic elastance (Ees) ratio (Ea/Ees). The Ea reflects the total arterial load of LV, whereas Ees reflects the LV systolic function. A recent study found that inappropriate VAC based on increased Ea/Ees estimated by echocardiography is associated with advanced disease severity in dogs with myxomatous mitral valve disease (MMVD). Hypothesis: Inappropriate VAC assessed by echocardiographic estimation of Ea/Ees is associated with a worse prognosis in dogs with MMVD. Animals: Eighty‐nine dogs with MMVD. Methods: Prospective cohort study. Dogs underwent echocardiographic examinations at enrollment. The Ea was estimated using the formula: mean blood pressure/(forward stroke volume/body weight). The Ees was estimated using the formula: mean blood pressure/(LV end‐systolic volume/body weight). The Ea/Ees was calculated. Results: By end of study, 22 dogs died of cardiac‐related causes with 67 dogs censored. Dogs with increased Ea/Ees (Ea/Ees >0.34; median survival time, 527 days; 95% confidence interval [CI], 322 days‐not determinable) had a shorter survival time ( P < .0001) than those without increased Ea/Ees (Ea/Ees ≤0.34; median survival time, >1112 days; 95% CI, not determinable). Multivariate Cox proportional hazard analysis showed that Ea/Ees, body weight, peak systolic mitral annular velocity, and the peak early diastolic transmitral velocity‐to‐peak early diastolic mitral annular velocity ratio were independent predictors of cardiac‐related death among echocardiographic indices. Conclusions and Clinical Importance: Inappropriate VAC assessed based on echocardiographically‐estimated Ea/Ees is associated with a worse prognosis in dogs with MMVD.