Relationship between PET-CT ischemia reduction and echocardiographic recovery after CTO-PCI
T Carlos, I Cruz, L Leite, A Barbosa, L Rocha, M Grine, B Resende, A Gomes, R Silva, L Goncalves, M Castelo-Branco, A Abrunhosa, M J FerreiraAbstract
Introduction
The influence of ischemia and myocardial viability on functional recovery after percutaneous coronary intervention (PCI) for chronic total occlusions (CTO) remains uncertain. Semiquantitative myocardial perfusion assessment with [13N]NH3 positron emission tomography–computed tomography (PET-CT) may help clarify how ischemia burden relates to left ventricular improvement.
Purpose
Evaluate the association between changes in PET-derived semiquantitative perfusion with echocardiographic parameters after CTO-PCI and investigate whether greater baseline ischemia or larger ischemia reduction predict superior global or regional functional recovery.
Methods
We conducted a prospective single-center study of 54 patients with chronic total occlusion (CTO), of whom 37 underwent CTO-PCI and completed paired [¹³N]NH₃ PET-CT and transthoracic echocardiography before and at 6-month follow-up. PET analysis included the global summed difference score (SDS), percentage SDS (SDS%), and regional SDS within the CTO territory. Echocardiographic assessment comprised left ventricular ejection fraction (LVEF), global longitudinal strain (GLS), and regional wall motion score (RWMS). Statistical analyses used paired comparisons, Spearman correlations, and linear regression models (univariate and multivariate adjusted for age, sex, baseline LVEF and prior myocardial infarction in CTO territory).
Results
CTO-PCI led to significant reductions in both global ischemia (ΔSDS −6 ± 6, p<0.001) and regional ischemia within the CTO territory (ΔSDS −4 ± 4, p<0.001). Despite these perfusion improvements, echocardiographic recovery was minimal (ΔLVEF 0.6%, p=0.561; ΔGLS 0.5%, p=0.322). In univariate analyses, global ΔSDS demonstrated a weak inverse correlation with ΔLVEF (ρ = −0.356, p = 0.031), whereas its associations with RWMS and GLS, as well as those of regional ΔSDS, were not significant. Baseline ischemia burden—global or territory-specific—was not associated with subsequent changes in echocardiographic measures. In multivariate models adjusted for clinical characteristics and baseline ventricular function, neither changes in SDS nor baseline SDS metrics independently predicted ΔLVEF, ΔRWMS, or ΔGLS. Across outcomes, the baseline value of each echocardiographic parameter remained the strongest predictor of its change at follow-up.
Conclusion
Although CTO-PCI produced substantial reductions in global and regional ischemia, echocardiographic measures of left ventricular function showed minimal improvement and were not independently associated with baseline ischemia or its reduction. These findings indicate a disconnect between PET-derived perfusion improvement and short-term echocardiographic recovery in CTO patients, underscoring the complexity of evaluating myocardial functional response after revascularization.For image description, please refer to the figure legend and surrounding text.For image description, please refer to the figure legend and surrounding text.