Predictive and prognostic value of stress myocardial perfusion imaging in patients with successful or failed recanalization to chronic total coronary occlusions

Objectives Percutaneous coronary intervention (PCI) to chronic total occlusion (CTO) is reported to be a beneficial effect to future cardiac events and prognosis. However it may be important to identify myocardial ischemia and viability on the CTO related myocardium before PCI. Our aim of this study is clarify whether stress myocardial perfusion imaging (MPI) is able to predict successful PCI to CTO, and is useful for predicting prognosis.

Methods We retrospectively registered 110 patients with CTO who underwent PCI to the CTO lesion. All patients underwent stress MPI before the PCI, and were divided into 2 groups based on the outcome of successful (group1) or failed recanalization (group2). We evaluated SPECT images using 17-segment defect scores graded on a 5-point scale, summed stress score (SSS), rest score (SRS) and difference scores (SDS). CTO related defect scores were also calculated (SSS_CTO, SRS_CTO, and SDS_CTO). Total events (coronary intervention > 3 months after the PCI, unstable angina, heart failure, AMI and death) during the follow-up were also investigated.

Results Overall success of recanalization for CTO was 70% (n=77, group1). Success of recanalization was related to no history of bypass graft operation (CABG) (p=0.012) and higher SDSCTO (p=0.007) according to multivariate analysis. Thirty seven events occurred during the follow-up (54+/-30 months). There was no significant difference in disease free survival rate between group 1 and 2. In group 2 (n=33), only SRS_CTO was associated with total events (p=0.036) according to Coxhazard analysis.

Conclusions Successful recanalization is likely to be carried out in patients with no history of CABG and larger CTO related ischemic burden. Events occurred more frequently to patients with larger CTO related infarct area among failed PCI patients. Stress MPI is useful for therapeutic stratification to CTO lesion.