Incidence and treatment of severe primary mitral regurgitation in contemporary clinical practice.

Abstract

Mitral regurgitation (MR) is a common valvular disorder, occurring in up to 10% of the general population. Although surgery is the established treatment for primary MR, many patients do not receive appropriate therapy. The objective of this study was to determine the incidence and treatment pattern of patients with severe MR evaluated at a tertiary medical center and determine factors associated with receiving surgery. All patients with moderate-severe and severe MR undergoing transthoracic echocardiography from 2011 to 2016 were identified. Patients with prior mitral valve surgery were excluded. Treatment recommendations were classified as referral to cardiology, referral to cardiothoracic surgery (CTS), receiving mitral valve surgery or receiving MitraClip. A multivariate logistic regression model was used to evaluate factors associated with referral to CTS or receiving surgery. During the study period, 1918 transthoracic echocardiogram were performed and 412 patients with moderate-severe or severe MR were identified. One hundred sixty-six patients (40%) had primary MR and 246 patients (60%) had secondary MR. For those with primary MR, 75 patients (45%) received treatment (surgery, n = 60 and MitraClip, n = 15) and 91 patients (55%) did not receive treatment. One hundred patients (60%) were referred to CTS and 128 patients (77%) were referred to cardiology. Patients undergoing surgery were younger (62.6 ± 14.2 years vs 72.0 ± 14 years, p < 0.001), with a higher prevalence of heart failure (57% vs 40%, p = 0.044) and a lower prevalence of stroke (3% vs 24%, p < 0.001) and hypertension (54% vs 74%, p = 0.012), compared to patients not undergoing surgery, respectively. Ejection fraction (60.4 ± 10.9% vs 56.3 ± 11.6%, p = 0.034), left ventricular end diastolic diameter (53.2 ± 10.3 mm vs 48.7 ± 10.9 mm, p = 0.040) and effective regurgitant orifice area (0.5 ± 0.4 cm2 vs 0.3 ± 0.1 cm2) were higher in patients undergoing surgery, compared to patients not undergoing surgery, respectively. The most common reason for not receiving surgery was that MR was not addressed by the treating physician and lost to clinical follow-up. Over 50% of patients that did not receive surgery had at least 1 indication based upon current practice guidelines. In contemporary clinical practice, less than half of patients with moderate-severe and severe primary MR received surgery and many were not referred for surgical consultation.