Predicting Functional Recovery After Coronary Chronic Total Occlusion Revascularization

Chronic total occlusion (CTO) is defined as complete coronary occlusion with TIMI flow grade 0 persisting for more than three months, identified in 15-25% of patients undergoing coronary angiography.¹,² CTO is associated with refractory angina, left ventricular dysfunction, and increased long-term mortality.³ Revascularization aims to restore anterograde flow and improve myocardial perfusion; however, functional recovery-a patient-centered endpoint-remains variable and poorly predicted.⁴ ,⁵ Available data demonstrate that left ventricular ejection fraction (LVEF) alone is insufficient.⁵ ,⁶ Cardiac magnetic resonance (CMR)-derived extracellular volume predicts recovery (OR 0.38; p=0.019), but CMR is not universally accessible.⁷ Stress echocardiography-derived myocardial work indices (GWI, GCW, GWE, GWW) have been validated in non-CTO populations, detecting dysfunction independent of LVEF and GLS, yet remain unstudied in CTO.⁸ ,⁹ Inflammatory biomarkers-monocyte-to-HDL ratio (MHR), soluble ST2 (sST2), and PIIINP-have shown prognostic value individually, but have not been integrated with myocardial work or procedural data.¹⁰ ,¹¹,¹² Procedural technique (antegrade vs. retrograde) affects procedural success but has not been evaluated as an independent predictor of functional recovery.¹³,¹⁴ The current strategy relies on fragmented, single-domain predictors, with no integrated pre-procedural model. This research addresses that gap by combining mechanical (myocardial work), biological (MHR, sST2, PIIINP), and technical (procedural technique) domains into a unified predictive model. The rationale is that functional recovery is multifactorial, and an integrated model will outperform single-domain approaches, enabling better patient selection, procedural planning, and expectation setting.

Inclusion Criteria: * Patients with symptomatic and documented CTO confirmed by coronary angiography with TIMI 0 flow lasting ≥3 months Age ≥18 years Referred for percutaneous coronary intervention (PCI) Provision of written informed consent Exclusion Criteria: * Acute myocardial infarction within 7days (as Acute inflammation contaminates biomarkers, within 7 days of an acute MI, sST2, MHR, and PIIINP values will reflect the acute infarction, not the chronic CTO state. the measured inflammatory response to a fresh myocardial injury, not the stable inflammatory milieu of a patient with a chronic total occlusion) and also stress test is contraindicated post-recent MI . Severe valvular heart disease (aortic stenosis with peak velocity ≥4.0 m/s or mean gradient ≥40 mmHg; mitral regurgitation graded severe; or any valvular lesion requiring imminent intervention)- because it independently alters myocardial work indices and is a contraindication to stress echocardiography ) and any significant valvular lesion that may independently affect LV function and alter myocardial stress indices . Contraindications to stress echocardiography Life expectancy \