Functional Mitral Regurgitation and Congestive Heart Failure in Sickle Cell Anemia and Hemoglobin SC Disease

Abstract

Introduction Anemia, a risk factor for cardiovascular disease, is associated with changes in left ventricle (LV) structure and physiology, namely LV dilation and hypertrophy. Patients with sickle cell anemia (HbSS) and hemoglobin SC disease (HbSC) exhibit similar changes in cardiac morphology and function. LV dilation increases the risk of functional mitral regurgitation (FMR), the abnormal mitral valve (MV) leaflet coaptation secondary to MV annulus dilation, resulting in valve insufficiency. FMR is associated with the development of congestive heart failure (CHF). Hypothesis HbSS and HbSC are associated with LV and additional cardiac chamber changes that increase the risk of FMR and CHF. Methods A retrospective, cross-sectional study was performed in adult patients with HbSS and HbSC. Clinical and hematologic data was obtained based on date of echocardiography. Perason chi-square analysis assessed differences in clinical, hematologic, and echocardiographic parameters in HbSS patients with and without FMR, and HbSC patients with and without FMR. Additional analysis assessed differences between HbSS patients with FMR and HbSC patients with FMR. Results Among HbSS patients (n=225), those with FMR (n=116) had a higher mean age (39.6, p=0.045) and rate of kidney disease (20.7% v. 9.2%, p=0.014) than those without FMR, and a higher rate of CHF (7.8% v 0.8%, p=0.009). HbSS patients with FMR had lower mean hemoglobin (Hgb) level (mean 7.61 g/dL, standard deviation [SD] 1.34, p=0.034), and higher mean tricuspid max velocity (TV max vel mean 232.97 cm/sec, SD 56.02, p=0.040) and pulmonary artery systolic pressure (PASP mean 32.039 mmHg, SD 14.15, p=0.013). Among patients with HbSC (n=82), those with FMR (n=27) had lower mean Hgb (mean 10.35, SD 1.29, p=0.006) than those without FMR, but no significant differences in rates of CHF or in structural or physiologic parameters were observed. Comparison of HbSS patients with FMR to HbSC patients with FMR showed no difference in rate of CHF. HbSS patients had lower Hgb level (mean 7.608, SD 1.44, p Conclusion In patients with HbSS and HbSC, differences in Hgb were seen in those with and without FMR, both within individual genotypes and across as well. The differences observed in cardiac morphology and physiology in HbSS and HbSC patients suggest that FMR can contribute to cardiac pathophysiology, pulmonary hypertension, and symptomatic CHF in patients with sickle hemoglobinopathies, and further stress the need for echocardiographic screening guidelines in sickle cell disease, both HbSS and HbSC.