919-12 Transient Wall Motion Abnormalities Following Rotational Coronary Atherectomy are Reflective of Myocardial Stunning More than Microinfarction

Abstract

Transient wall motion abnormalities (WMA) have been found following rotational coronary atherectomy (ROTA) in the majority of patients assessed by serial echocardiography. A possible mechanism of transient WMA in this setting is myocardial stunning secondary to distal embolization of atherosclerotic debris from the ROTA site as defined by regional transient dysynergy resolving completely by 24 hours post ROTA. Microinfarction in the setting of myocardial stunning is an additional explanation for this phenomena, and the prevalence of microinfarction in the setting of stunning has not been determined. We screened selected patients with transient WMA post-ROTA for troponin I, myoglobin and CKMB release as a screening for myocardial necrosis. We studied 9 patients: 8/9 male, 7/9 LAD lesion, 2/9 RCA lesion. All patients had adjunctive post ROTA balloon angioplasty except one who required a 3.0 mm Cook stent. In this welect patient group wall motion was normal in all patients before intervention and within 24 hours following ROTA. Following ROTA peak onset of WMA ranged from 5–27 min, mean maximal %WMA 28.3% ± 11.89%, and median time to full recovery of wall motion was 88 min ± 655 min. Evidence of myocardial necrosis (positive markers) was present in 3/9 patients following ROTA with the evolution of transient ECG T wave abnormalitics 3/3, increased CKMB > 7.5 ng/ml (range 25–72) 2/3, increased myoglobin level 2/3 and increased troponin I > 1.35 ng/ml (range 3.88–15.9) in 3/3 patients. None of the remaining patients developed any indicator of myocardial necrosis. max%WMA Median Time to Recovery p Positive Markers n = 3 28.3% (16–35%) 63 min (24–180 min) NS Negative Markers n = 6 28.0% (12–44%) 88 min (24–270 min) NS Despite prolonged recovery times and extensive transient %WMA, reflective of myocardial stunning, these factors were not predictive of troponin I release following successful ROTA. Thus microinfarction may occur in the context of myocardial stunning, yet the dominant mechanism transient WMA is likely to be myocardial stunning.