Abstract 4145764: Mitral Annular Calcification (MAC) and Stroke Risk: A Single Center Cohort Analysis of stroke outcomes across the spectrum of MAC Severity

Background: Stroke is one of the leading causes of long-term disability and mortality worldwide. Of ischemic stroke etiologies, cardio-embolism both causes more severe strokes and is responsible for an increasing share of the ischemic stroke etiologies in the developed world. Mitral annular calcification (MAC), chronic degeneration of the fibrous base of the mitral valve, has been implicated by association with increased stroke risk. However, there has been conflicting evidence regarding the causative relationship between MAC and stroke risk. Although the 2008 CHEST guidelines recommended antithrombotic therapy with aspirin to mitigate stroke risk, the updated 2012 CHEST guidelines question the role of antithrombotic therapy since stroke may be due to embolized calcific spicules. 2020 American College of Cardiology / American Heart Association guidelines do not make recommendations regarding stroke prevention in MAC. Our study sought to assess the association of MAC and its severity with stroke outcomes. Hypothesis: We hypothesize an association between MAC and stroke which increases with increasing MAC severity Methods: We retrospectively studied patients undergoing transthoracic echocardiography in a single center cohort from 2005 through 2017. MAC severity was determined based on documented echo reports. Multivariable cox regression analysis was used to assess for correlation with stroke and was adjusted for diabetes, hypertension, hyperlipidemia, infection, endocarditis, lupus, prior MI, mitral disease, OSA, PAD, and prosthetic valves. Results: The cohort included 2,837 patients. Of the full cohort, 393 had no MAC, 1686 had mild MAC, 537 with had moderate MAC, and 221 had severe MAC. Mean age (57.2 to 68.6) and female gender rates (49.4% to 71%) significantly increased with increasing MAC severity. At median follow up of 73 months (IQR 6.1,103.7) there were a total of 92 stroke events. Cox regression analysis found aHR of 1.45 (0.74-2.84, p=0.28), 1.16 (0.52-2.59, p=0.72), and 1.23 (0.44-3.44, p=0.69), for mild, moderate, and severe MAC, respectively, when compared to patients without MAC. Conclusion: In a large single center cohort, there was no association found between MAC and stroke outcomes, regardless of severity.