Changes in renin‐angiotensin‐aldosterone system during cardiac remodeling after mitral valvuloplasty in dogs

BACKGROUND: Information regarding changes in renin‐angiotensin‐aldosterone system (RAAS) during cardiac remodeling after mitral valvuloplasty (MVP) in dogs remains lacking. HYPOTHESIS/OBJECTIVES: To assess the longitudinal effects of MVP on circulating RAAS activity. ANIMALS: Eight client‐owned dogs receiving MVP for myxomatous mitral valve disease (MMVD). METHODS: This is a cohort study. Plasma renin activity (PRA), angiotensin II (AT2), aldosterone (PAC), blood urea nitrogen (BUN), and creatinine concentrations, were measured in these dogs before (baseline) and at 3 consecutive monthly follow‐ups (Post‐1M, Post‐2M, Post‐3M). Echocardiography was concomitantly used to assess the process of cardiac recovery after MVP. RESULTS: The echocardiography revealed a significant decrease in LVIDDN, LA/Ao, FS, E velocity, E/A, E′ sep, S′ lat, E′ lat, and A′ lat after MVP compared with baseline (P < .05). There was a significant reduction in the PRA (2.45, 3.05, 2.74 vs 8.8 ng/mL/h; P = .002), AT2 (466, 315, 235 vs 1200 pg/mL; P = .009), and PAC (39.88, 47, 54.62 vs 179.5 pg/mL; P = .01), respectively at Post‐1M, Post‐2M, Post‐3M compared to the baseline. Additionally, BUN and creatinine concentrations decreased from Post‐1M. The RAAS variables showed significant, weak to moderate, relationship with selected echocardiographic variables. CONCLUSIONS AND CLINICAL IMPORTANCE: Mitral valvuloplasty contributes to decreased RAAS activity in MMVD dogs, which paralleled the process of cardiac reverse remodeling up to Post‐3M. This information facilitates formulating strategies to optimize clinical outcomes for dogs after MVP.