Abstract 12473: Impaired Baseline Coronary Microcirculatory Reserve Predicts Peri-percutaneous Coronary Intervention Myocardial Necrosis.
Background: Cardiac enzyme elevation after percutaneous coronary intervention (PCI) is a marker of myocardial necrosis and portends poor outcome. However, there is currently no clinically applicable method to predict peri-PCI myocardial necrosis (PMN) in the cardiac catheterization laboratory before it occurs. We hypothesized that impaired baseline microcirculatory reserve, by reducing ability to tolerate ischemic insults, is a risk for PMN, and that index of microcirculatory resistance (IMR) measured before PCI can predict PMN.
Methods: Patients undergoing elective PCI of a single target lesion in the left anterior descending artery without prior target territory infarction were recruited. A pressure-temperature sensor wire was used to obtain physiological measurements including mean transit time at rest (TmnR), hyperemic Tmn (TmnH), hyperemic proximal pressure (Pa), hyperemic distal pressure (Pd) and wedge pressure (Pw) prior to PCI. Hyperemia was induced by adenosine infusion (140 μg/kg/min). Fractional flow reserve (FFR = Pd / Pa), coronary flow reserve (TmnR / TmnH) and IMR (Pa × TmnH × [Pd − Pw] / [Pa − Pw]) were derived before PCI. Cardiac enzymes were collected 12 to 24 hours after PCI. PMN was defined as having post-PCI troponin levels > 10 × 99th percentile.
Results: Of the 45 patients studied, 10 had PMN. No patient had branch vessel compromise. From binary logistic regression analyses of all clinical, procedural and physiological parameters, univariate predictors of PMN were pre-PCI IMR (P = 0.001) and number of stents used (P = 0.004). Using receiver-operating curve analysis, pre-PCI IMR ≥ 28 had sensitivity of 80.0 % and specificity of 85.7 % of predicting PMN (c statistic 0.80, P = 0.004). In multivariate analysis, pre-PCI IMR was the only independent predictor of PMN. Pre-PCI IMR ≥ 28 was independently associated with a 15-fold risk of developing PMN (P = 0.005).
Conclusions: Patients with impaired microcirculatory reserve have a higher propensity for ischemic myocardial necrosis. IMR, a simple guidewire based measurement performed before PCI, can predict subsequent risk of developing myocardial necrosis, and may serve to guide adjunctive PMN prevention strategies.
- © 2010 by American Heart Association, Inc.