Abstract 4570: Recanalization of Coronary Chronic Total Occlusion Guided by Left Ventricular Function, Perfusion and Viability Imaging by Cardiovascular Magnetic Resonance
Background. The benefit of recanalizing a coronary chronic total occlusion (CTO) is controversial. We sought to investigate whether cardiovascular magnetic resonance (CMR) with LV function, perfusion and viability imaging can select patients that can benefit from revascularization.
Methods. Fifty-two consecutive patients with CTO were recruited in the study and underwent CMR perfusion before recanalization (44±99 days). Stress first-pass perfusion imaging was performed after 4 minutes of 140μg/kg/min adenosine and 0.1mmol/Kg of gadolinium, followed by late enhancement and cine imaging encompassing the left ventricle from base to apex. The presence and extent of ischemia was quantified by myocardial perfusion reserve index (MPRI) in the CTO and remote territory. Infarct size, left ventricular volumes and ejection fraction (LVEF) were also evaluated.
Results: Thirty-nine patients underwent successful recanalization and a repeat adenosine CMR perfusion (4±4 months). Myocardial ischemia pre PCI was detected in the 30 patients (77%). No myocardial infarction was identified in 13 patients (42%), and a limited subendocardial infarction seen in 10 patients (33%). A complete or almost complete resolution of ischemia was seen in all 30 patients (p<0.0001) after PCI. MPRI in the CTO territory significantly improved after successful recanalization, from 1.8 pre-PCI to 2.3 post-PCI p<0.01. MPRI pre-PCI in the CTO territory was significantly lower than in the remote area (p<0.001). MPRI in the remote area did not change significantly from pre- to post-PCI: 2.2 to 2.5 (p=0.13). LVEF improved from 60±13% to 63±13% (p<0.001) due to a decrease of ESV from 70±40ml to 61±41ml (p<0.001); EDV did not change significantly. A new but limited post-procedural myocardial infarction was detected in 7 patients (18%), likely to represent peri-procedural distal embolization or side branch impairement.
Conclusion. The majority of patients with CTO had extensive myocardial ischemia and limited myocardial infarction. Recanalization of CTO improved MPRI and is associated with improved LV function. CMR is a useful non-invasive method that could improve selection of patients that can benefit from recanalization and assess the results of the intervention.