Improvement of myocardial function and perfusion after successful percutaneous revascularization in patients with chronic total coronary occlusion

Background: Percutaneous coronary intervention (PCI) for chronic total occlusion (CTO) of a coronary artery can provide benefits in terms of myocardial function and survival but the procedure is complex and the success rate is relatively low. To assess these benefits, myocardial function, ischemia and viability should be clearly determined by means of a reliable diagnostic test. This study aimed to assess ventricular function and myocardial ischemia before and after PCI for CTO using cardiac magnetic resonance (CMR). NYHA functional class was also assessed before and after PCI. Methods and results: CMR studies were performed in 43 consecutive patients (7 females; aged 64 ± 9.6 y.o.) with CTO scheduled for PCI and repeated 6 months post-PCI. PCI was successful in 33 (77%) of them. In this group CMR had shown inducible perfusion defects in 26 (79%) before PCI, while they were observed in 10 (30%) post-PCI CMR study (p < 0.001). The number of segments showing inducible perfusion defect (3.4 ± 2 prevs. 2.9 ± 4.5 post-PCI, p = 0.002) was significantly reduced in this group. Regional contractile function of segments showing viability also improved significantly in the group with successful CTO PCI compared to the group with an unsuccessful procedure. NYHA functional class for angina also improved in patients with successful revascularization while it remained unchanged in the group with unsuccessful procedures. Conclusions: A successful CTO PCI leads to a reduction in inducible myocardial ischemia and to an improvement in regional wall motion, which results in clinical improvement.