Myocardial Blood Flow and Inflammatory Cardiac Sarcoidosis

OBJECTIVES This study sought to evaluate the effects of inflammatory sarcoid disease on coronary circulatory function and the response to immune-suppressive treatment. BACKGROUND Although positron emission tomography assessment of myocardial inflammation is increasingly applied to identify active cardiac sarcoidosis, its effect on coronary flow and immune-suppressive treatment remains to be characterized. METHODS Thirty-two individuals, who were referred for positron emission tomography/computed tomography, were evaluated for known or suspected cardiac sarcoidosis applying F-18-fluorodeoxyglucose to determine inflammation and N-13-ammonia to assess for perfusion deficits following a high-fat/low-carbohydrate diet and fasting state >12 h to suppress myocardial glucose uptake. Inflammation was quantified with standardized uptake value and regional myocardial blood flow at rest and during regadenoson-stimulated hyperemia was determined in ml/g/min. Positron emission tomography studies were repeated in 18 cases with a median follow-up of 2.5 years (interquartile range [IQR]:1.3 to 3.4 years). RESULTS Twenty-five exams had normal perfusion but evidence of regional inflammation (group1), and 21 exams presented a regional perfusion deficit associated with inflammation (group 2). Median myocardial blood flow did not differ between inflamed and noninflamed myocardium in both groups (0.86 ml/g/min [IQR: 0.66 to 1.11 mt/g/min] vs. 0.83 ml/g/min [IQR: 0.64 to 1.12 ml/g/min] and 0.74 ml/g/min [IQR: 0.60 to 0.93 ml/g/min] vs. 0.77 ml/g/min [IQR: 0.59 to 0.95 ml/g/min], respectively). As regards median hyperemic myocardial blood flows, they were significantly lower in the inflamed than in the remote regions in group 1 and 2 (2.31 ml/g/min [IQR: 1.81 to 2.95 ml/g/min] vs. 2.70 mVg/min [IQR: 2.07 to 3.30 ml/g/min] and 1.61 ml/g/min [IQR: 1.17 to 2.18 ml/g/min] vs. 1.94 mVg/min [IQR: 1.49 to 2.39 ml/g/min]; p < 0.001, respectively). Immune-suppression-mediated decrease in inflammation was associated with preserved myocardial flow reserve (MFR) at follow-up, whereas MFR significantly worsened in regions without changes or even increases in inflammation (median Delta MFR: 0.07 [IQR:-0.29 to 0.45] vs.-0.24 [IQR:-0.84 to 0.21]; p < 0.001). There was an inverse correlation between pronounced alterations in myocardial inflammation (Delta regional myocardial volume with standardized uptake value >4.1) and Delta MFR (r =-0.47; p = 0.048). CONCLUSIONS Sarcoid-mediated myocardial inflammation is associated with a regional impairment of coronary circulatory function. The association between immune-suppressive treatment-related alterations in myocardial inflammation and changes in coronary vasodilator capacity suggests direct adverse effect of inflammation on coronary circulatory function in cardiac sarcoidosis. (C) 2017 by the American College of Cardiology Foundation.