No abstract

After primary PCI was completed, intracoronary nitroglycerin (100-200 μg) was administered and a coronary pressure wire (St. Jude Medical) was calibrated, equalized to the guide catheter Background-Most methods for assessing microvascular function are not readily available in the cardiac catheterization laboratory. The aim of this study is to determine whether the Index of Microcirculatory Resistance (IMR), measured at the time of primary percutaneous coronary intervention, is predictive of death and rehospitalization for heart failure. Methods and Results-IMR was measured immediately after primary percutaneous coronary intervention in 253 patients from 3 institutions with the use of a pressure-temperature sensor wire. The primary end point was the rate of death or rehospitalization for heart failure.

The index of microcirculatory resistance measured acutely was higher in patients with MVO on ceCMR, and IMR independently predicted LV function and infarct volume. This easily measured physiological parameter provides important prognostic information at the time of emergency PCI.

Background-Magnetic resonance myocardial perfusion imaging (MRMPI) has a number of advantages over the other noninvasive tests used to detect reversible myocardial ischemia. The majority of previous studies have generally used quantitative coronary angiography as the gold standard to assess the accuracy of MRMPI; however, only an approximate relationship exists between stenosis severity and functional significance. Pressure wire-derived fractional flow reserve (FFR) values Ͻ0.75 correlate closely with objective evidence of reversible ischemia. Accordingly, we have compared MRMPI with FFR. Methods and Results-One hundred three patients referred for investigation of suspected angina underwent MRMPI with a 1.5-T scanner. The stress agent was intravenous adenosine (140 g · kg Ϫ1 · min Ϫ1 ), and the first-pass bolus contained 0.1 mmol/kg gadolinium. In the following week, coronary angiography with pressure wire studies was performed. FFR was recorded in all patent major epicardial coronary arteries, with a value Ͻ0.75 denoting significant stenosis. MRMPI scans, analyzed by 2 blinded observers, identified perfusion defects in 121 of 300 coronary artery segments (40%), of which 110 had an FFR Ͻ0.75. We also found that 168 of 179 normally perfused segments had an FFR Ն0.75. The sensitivity and specificity of MRMPI for the detection of functionally significant coronary heart disease were 91% and 94%, respectively, with positive and negative predictive values of 91% and 94%. Conclusion-MRMPI can detect functionally significant coronary heart disease with excellent sensitivity, specificity, and positive and negative predictive values compared with FFR. (Circulation. 2009;120:2207-2213.)