Myocardial Perfusion Grade After Late Infarct Artery Recanalization Is Associated With Global and Regional Left Ventricular Function at One Year

Abstract

Background— Whether myocardial perfusion grade (MPG) following late recanalization of infarct-related arteries (IRAs) predicts left ventricular (LV) function recovery beyond the acute phase of myocardial infarction (MI) is unknown. Methods and Results— The Total Occlusion Study of Canada-2 enrolled stable patients with a persistently occluded IRA beyond 24 hours and up to 28 days post-MI. We studied the relationship between the initial MPG and changes in LV function and volume as well as the change in MPG from immediate post-percutaneous coronary intervention (PCI) to 1 year in 139 PCI patients with thrombolysis in myocardial infarction grade 3 epicardial flow post-PCI and with paired values grouped into impaired or good MPG groups (MPG 0/1 or MPG 2/3). MPG 0/1 patients were more likely to have received thrombolytic therapy and to have a left anterior descending IRA. They had lower blood pressure and LV ejection fraction (LVEF) and a higher heart rate and systolic sphericity index at baseline. Changes in the MPG 0/1 and MPG 2/3 groups from baseline to 1 year were LVEF, 3.3±9.0% and 4.8±8.9% ( P =0.42); LV end-systolic volume index (LVESVI), −1.1±9.2 and −4.7±12.3 mL/m 2 ( P =0.25); LV end-diastolic volume index (LVEDVI), 0.08±19.1 and −2.4±22.2 mL/m 2 ( P =0.67); and SDs/chord for infarct zone wall motion index (WMI), 0.38±0.70 and 0.84±1.11 ( P =0.01). By covariate-adjusted analysis, post-PCI MPG 0/1 predicted lower WMI ( P <0.001), lower LVEF ( P <0.001), and higher LVESVI ( P <0.01) but not LVEDVI at 1 year. Of the MPG 0/1 patients, 60% were MPG 2 or 3 at 1 year. Conclusions— Preserved MPG is present in a high proportion of patients following late PCI of occluded IRAs post-MI. Poor MPG post-PCI frequently improves MPG over 1 year. MPG graded after IRA recanalization undertaken days to weeks post MI is associated with LV recovery, indicating that MPG determined in the subacute post-MI period remains a marker of viability. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00025766.