Does Coronary Artery Morphology Predict Favorable Results of Intracoronary Thrombolysis in Patients With Unstable Angina Pectoris?

The efficacy of intracoronary thrombolysis (ICT) for unstable angina pectoris (UAP) has been limited, despite the similar pathogenesis between UAP and acute myocardial infarction. To ascertain the subset of UAP suitable for ICT, the clinical responses to ICT were assessed in patients with UAP. Eighty-2 patients with medically refractory angina were divided into 2 groups according to the coronary artery morphology of the culprit lesion before ICT: (1) lesions with acute cut off and/or filling defects (AC) and (2) lesions with a tapered shape (TA). The TIMI flow grade was determined from coronary angiograms before and immediately after ICT. The diameter stenosis (%DS) and minimal lumen diameter (MLD) of the culprit lesion were determined using quantitative coronary angiographic analysis before and immediately after ICT. In addition, inhospital cardiac event rates including urgent/emergency coronary angioplasty or bypass surgery, nonfatal myocardial infarction or cardiac death were compared between the 2 groups. Multivariate logistic regression analysis was performed using 13 clinical factors contributing to successful ICT. The results showed that all 3 coronary angiographic parameters (TIMI flow, %DS, and MLD) significantly improved in the AC group (p<0.01, p<0.01 and p<0.05, respectively), whereas none of these parameters improved in the TA group. The inhospital cardiac event rate after ICT was significantly higher in the TA group (76%) than in the AC group (48%; p=0.016). Odds ratio predicting successful ICT was 7.09 (p<0.01) for the AC lesion, and 2.54 (p<0.01) for new angina. In conclusion the AC lesions are more commonly associated with coronary thrombosis that responds to ICT than are the TA lesions. Thus, the coronary angiographic morphology may be an important predictor for a successful ICT in patients with medically refractory UAP.