Abstract 2486: Impaired Myocardial Perfusion at the End of Percutaneous Coronary Intervention (PCI) is Associated with Continuous ECG Ischemia Immediately Following PCI which is then Associated with Myonecrosis Hours Later. A PROTECT-TIMI 30 Substudy
Background: Continuous ECG (CECG) ischemia before PCI has been associated with adverse outcomes, but there is little data evaluating its timing, prevalence and association following PCI with angiographic and clinical outcomes.
Methods: CECGs were obtained for 48h after PCI in the PROTECT-TIMI 30 trial (n=800). Ischemia was defined as ≥1mm ST dev which persisted for >1 min. A peri-procedural MI was defined as ≥1 CKMB measurement ≥ 3 times the ULN after PCI. TIMI Myocardial Perfusion Grade (TMPG) was assessed at the completion of the PCI.
Results: Impaired TMPG 0/1 and the occurrence of MI were associated with early and sustained excess in CECG ischemia beginning immediately after PCI. (Figure⇓). The time to the first biomarker diagnosis of MI was 8.8 hrs after the procedure (IQR 7.2, 12.9) while the time to the preceding ischemic event on CECG among these same patients was earlier (7.5 min after PCI) (Figure⇓). CECG ischemia was associated with MI (28.7 v. 8.4%, p<0.001), a greater increase in levels of CKMB from baseline to peak (1.2 v. 0.3 ng/ml, p=0.007) and a greater likelihood of having a rise in CKMB greater than 5 ng/ml after PCI (30.4% vs. 15.7%, p=0.001).
Conclusion: While biomarkers are traditionally ascertained at discrete time intervals, CECG identifies ischemia continuously and thereby offers unique insight into the timing of ischemic events that eventuate in biomarker elevations. Abnormal myocardial perfusion following PCI is associated with CECG ischemia in the minutes following PCI, and this in turn is associated with a first rise in biomarkers 8.8 hours later. Interventions designed to reduce MI following the procedure must then be effective at the time of the procedure.