Objective To assess the role of CMR in the treatment of true chronic total occlusions (CTO) with percutaneous coronary intervention (PCI) and drug eluting stent implantation.
Introduction Successful PCI for CTO may confer an improved prognosis and a reduction in major adverse cardiac events (MACE). However most trials have included occlusions of short duration (less than 4 weeks). In this study we assessed the impact of PCI on LV function in patients with true CTOs (TIMI flow grade 0 and greater than 12 weeks duration) using serial CMR imaging as well as the predictive value of late gadolinium enhancement when performed prior to revascularisation.
Methods Thirty patients referred for PCI to a single vessel CTO underwent CMR examination prior to and 6 months after PCI. Technical success was defined as recanalisation of the occluded vessel and DES implantation with a final residual diameter stenosis <30%. LV function and infarct size were assessed using a 1.5T GE MRI system. Segmental wall thickening (SWT) was measured within the perfusion territory of the CTO using the 16-segment model and segments were dysfunctional if the SWT was ≤45%. The transmural extent of infarction (TEI) was calculated by dividing the hyperenhanced area by the total area×100; a score of ≤25% were considered viable.
Results Technical success was achieved in 19 of the 30 patients (63%). CTO duration was greater in patients with failed revascularisation but other baseline demographics were well matched between groups (Abstract 31 table 1). PCI-CTO success resulted in a significant increase in LVEF when compared to both baseline (50±13 vs 54±11; p<0.01) and with PCI-CTO failure (11.8±19.8 vs -2.3±5.1, p<0.01, Abstract 31 figure 1). In dysfunctional but viable segments only PCI success conferred a significant improvement in SWT compared to baseline (26±6 vs 40±10; p<0.001, Abstract 31 figure 2). There were no episodes of MACE in either group at 21 months follow-up.
Conclusion PCI-CTO success of true CTOs can improve global LV function. The TEI, assessed with CMR, can be used to help predict improvements in regional wall function. PCI-CTO failure was not associated with increased MACE at medium-term follow-up.
- Chronic total occlusion
- cardiac magnetic resonance
- left ventricular function