Computed Tomography Angiography Prediction Score for Percutaneous Revascularization of Chronic Total Occlusions

Overview

Chronic total occlusions (CTO) are encountered in almost one-fourth of patients undergoing coronary angiography. The presence of an untreated CTO has been related to adverse clinical prognosis, both in stable angina and acute myocardial infarction, and is often associated with persistent symptomatic angina. Depending on their symptomatic and functional status as well as anatomical complexity, CTO can be treated by optimal medical therapy only or therapy combined with coronary revascularization. The potential benefits of percutaneous coronary intervention (PCI) in CTO include symptom relief, improved left ventricular function, and potentially a survival advantage associated with success when compared with failed revascularization. Of note, marked advances in endovascular techniques and device technology have resulted in substantial improvements of procedural success rates of PCI in CTO. In spite of these advances, the vast majority of patients with CTO are still being managed medically or referred for coronary bypass surgery rather than PCI. The most common reason for deferring PCI in patients with CTO appears to be the uncertainty of predicting the procedural outcome of percutaneous revascularization. Further barriers to attempting CTO by PCI include the difficulty of gauging the time required for the procedure and the use of resources. The CT-RECTOR (Computed Tomography REgistry of Chronic Total Occlusion Revascularization) study was designed to evaluate the application of coronary computed tomography angiography (CTA) for the prediction of procedural outcome of PCI in CTO in an international patient population. The main purpose of this multicenter registry is to develop a noninvasive CTA-based prediction tool (CT-RECTOR Score) for grading CTO suitability for PCI.

Coronary CTA has recently emerged as a valuable noninvasive tool to provide guidance during percutaneous treatment of CTO. The main advantages of coronary CTA in characterization of CTO include the 3-dimensional visualization of occlusion trajectory and morphology as well as the exact evaluation of calcifications. Despite this, and although prior single-center studies suggested a potential utility of individual coronary CTA-based CTO characteristics for predicting PCI, there has been no compiled prediction model for grading CTO suitability for PCI in a large cohort of patients. The CT-RECTOR registry is a retrospective, multicenter observational study of patients undergoing preprocedural coronary CTA before attempted PCI of CTO between 2007 and 2013. The study was designed to enroll 250 consecutive patients at 4 high-volume cluster sites in 2 European countries. CT-RECTOR sites were chosen on the basis of adequate coronary CTA volume and PCI proficiency to reflect the state-of-the-art, ''real-life'' management of patients with CTO.