Predictors of improvement in left ventricular function after percutaneous revascularization of occluded coronary arteries: A report from the Total Occlusion Study of Canada (TOSCA)

Background The Total Occlusion Study of Canada (TOSCA) is a multicenter, ra ndomized trial evaluating the effect of stenting with greater than or equal to1 heparin-coated stent on long-term potency after percutaneous coronary intervention by balloon angioplasty of occluded coronary arteries. The purp ose of the current study was to compare the effect of stenting and balloon angioplasty on global left ventricular ejection Fraction (LVEF) and regiona l wall motion and to examine what clinical and angiographic factors may hav e an effect on left ventricular function in this setting. Methods and Results Analysis at the core angiographic laboratory of paired baseline and follow-up left ventricular angiograms, as well as target vesse l potency, was possible in 244 of 410 cases. An improvement in LVEF was obs erved in the entire group (59.4%+/- 11% to 61.0%+/- 11%, P =.003). The LVEF change was +1.84 +/-7.54 in the stent group (P=.009) and 1.28 +/-8.16 in t he percutaneous transluminal coronary angioplasty group (P=.085). There was no significant intergroup difference. Patients with duration of occlusion less than or equal to6 weeks had an improvement in LVEF (+2.98 +/-8.68, P=. 0006), whereas those with an occlusion duration of >6 weeks had no improvem ent (+0.48 +/-7.01, P not significant), Multivariate analysis revealed base line LVEF <60%, duration of occlusion <less than or equal to>6 weeks, and C anadian Cardiology Society angina class I or II to be independent predictor s of improvement in LVEF, Conclusions The restoration of coronary patency of nonacute occluded corona ry arteries is associated with a small but significant improvement in regio nal and global left ventricular function, especially in patients with recen t occlusions and depressed left ventricular function. In spite of significa nt effect on long-term potency, stenting of nonacute coronary occlusions do es not result in significantly better left ventricular function compared wi th balloon angioplasty in this setting.