3D fusion between SPECT myocardial perfusion imaging and invasive coronary angiography to guide the treatment for patients with stable CAD

Objective We evaluated the value of three-dimensional (3D) fusion of SPECT myocardial perfusion imaging (MPI) with invasive coronary angiography (ICA) to guide coronary revascularization for patients with stable coronary artery disease (CAD). Methods A retrospective observational study of 621 patients who underwent SPECT MPI and ICA was conducted. Based on the location of perfusion deficit on SPECT MPI and stenosis on ICA, patients were classified into matched, unmatched, or normal groups via the fusion or side-by-side analysis. The treatments recommended by the fusion or side-by-side analysis were compared with those that the patients actually received. The treatment was defined as concordant if there was revascularization in concordance with the recommendation by the fusion or side-by-side analysis or if patient did not require revascularization; otherwise, it is classified as discordant. Major adverse cardiac events (MACE) were defined as all-cause and cardiac death, myocardial infarction, unstable angina requiring hospitalization or ICA, or unplanned revascularization. Results Over a five-year follow-up, 15.9% of patients experienced MACE. The MACE rates in the fusion and side-by-side groups were 19.8% and 24.4% for matched findings, 14.4% and 14.0% for unmatched findings, and 7.2% and 8.2% for normal findings, respectively (P50%, those who received the treatment concordant with fusion had significantly better outcomes compared to those who did not (16.8% vs 27.0%, P<0.05), particularly in the sub-group with intermediate stenosis (stenosis: 50-80%) (10.8% vs 26.5%, P<0.01). The treatment concordant with fusion is an independent protective factor against MACE (HR:0.48, CI:0.28-0.83 P<0.01) while the treatment concordant with the side-by-side analysis is not. The concordant group showed a significantly higher lesion vessel rate in the left circumflex artery (LCX) (31.2% vs. 14.3%, P<0.01) compared to the discordant group as classified by fusion. Conclusions 3D fusion before coronary revascularization can guide the treatment to improve outcomes among patients with known or suspected CAD, particularly those with intermediate stenosis.