Sildenafil treatment attenuates ventricular remodeling in an experimental model of aortic regurgitation

BACKGROUND: Currently there is no reliable medical treatment for aortic regurgitation (AR). METHODS: Thirty-nine Sprague–Dawley rats underwent creation of AR or sham operation. Treated rats were assigned to early or late institution of sildenafil therapy (100 mg/kg/day) for a total of 10 weeks. Treatment–effects were measured by serial echocardiography, invasive hemodynamic measurements, and tissue analysis. RESULTS: Rats assigned to early treatment developed less remodeling than untreated rats. Thus, left ventricular (LV) dilation was blunted by sildenafil with end–systolic diameter being significantly smaller (6.6 ± 0.4 vs. 7.7 ± 0.4 mm, respectively, p < 0.05). Also, LV wall thickness was significantly decreased in treated rats compared to controls (2.23 ± 0.08 vs. 2.16 ± 0.05 mm, p < 0.01). Fractional shortening was improved by treatment (p < 0.05). Myocardial fibrosis was borderline decreased by treatment (p = 0.09). Akt was increased in treated compared to controls (p < 0.05). CONCLUSION: Sildenafil slightly inhibits LV remodeling and improves fractional shortening in rats with AR when treatment is initiated early.