C. Judkins

The Index of Microcirculatory Resistance Postpercutaneous Coronary Intervention Predicts Left Ventricular Recovery in Patients With Thrombolyzed ST-Segment Elevation Myocardial Infarction

BACKGROUND The index of microcirculatory resistance (IMR), an invasive measure of microvascular function, has been shown to correlate with clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI). The aim of this study is to evaluate the predictive value of IMR on left ventricular recovery in patients undergoing a pharmacoinvasive strategy for STEMI. METHODS The index of microcirculatory resistance was assessed following percutaneous coronary intervention (PCI) in 31 patients with STEMI who were initially managed with thrombolysis. Other markers of microvascular function such as coronary flow reserve (CFR), TIMI flow grade, corrected TIMI frame count (cTFC), and ST-segment resolution were also recorded. All indices were evaluated against measures of left ventricular function and recovery 3 months postindex event. RESULTS The IMR correlated with left ventricular function, as assessed by wall motion score and ejection fraction at 3-month follow-up (r = 0.652, P = 0.005; r = -0.452, P = 0.011, respectively). The traditional methods of assessing microvascular function, such as CFR, TIMI flow grade, cTFC, and ST-segment resolution did not correlate with wall motion score and ejection fraction at 3 months. Post-PCI IMR was significantly lower in those patients with left ventricular recovery at 3 months (18 U vs 39 U, P < 0.001). The optimal cut-off value for post-PCI IMR and left ventricular recovery was 32 U. In patients in whom the IMR was greater than 32 U, the percent change in ejection fraction was significantly lower than in those patients in whom the IMR was less than 32 U (2 ± 11 vs 12 ± 8, P = 0.012). CONCLUSIONS In patients presenting with STEMI initially managed with thrombolysis and subsequently undergoing PCI, IMR correlates with measures of left ventricular function and has the potential to predict left ventricular recovery at 3 months.

Renal sympathetic nerve denervation for the treatment of resistant hypertension.

Improvements in BP control with pharmacotherapy undoubtedly translate into significant individual and population health benefits. RDN results in impressive reductions in BP, which are likely to be associated with further improvements in clinical outcomes. With more clinical trials and concurrent development of new devices, we hope that RDN holds up to its current accolades.

Measurement of microvascular function in patients presenting with thrombolysis for ST elevation myocardial infarction, and PCI for non-ST elevation myocardial infarction

BACKGROUND In this prospective study, we compared the invasive measures of microvascular function in two subsets: patients with pharmacoinvasive thrombolysis for STEMI, and patients undergoing percutaneous coronary intervention (PCI) for NSTEMI. METHODS The study consisted of 17 patients with STEMI referred for cardiac catheterisation post thrombolysis, and 20 patients with NSTEMI. Coronary physiological indexes were measured in each patient before and after PCI. RESULTS The median pre-PCI index of microcirculatory function (IMR) at baseline was significantly higher in the STEMI group than the NSTEMI group (26 units vs. 15 units, p = 0.02). Following PCI, IMR decreased in both groups (STEMI 20 units vs. NSTEMI 14 units, p = 0.10). There was an inverse correlation between post PCI IMR and left ventricular ejection fraction (LVEF) (r = -0.52, p = 0.001). Furthermore, post PCI IMR was an independent predictor of index admission LVEF in the total population (β = -0.388, p = 0.02). CONCLUSION Invasive measures of microvascular function are inferior in a pharmacoinvasive STEMI group compared to a clinically stable NSTEMI group. In the STEMI population, the IMR following coronary intervention appears to predict LVEF.