Perfusion and metabolic scintigraphy with ¹²³I-BMIPP in prognosis of cardiac resynchronization therapy in patients with dilated cardiomyopathy

The objective of the study was to investigate the left ventricular (LV) myocardial perfusion and metabolism in patients with idiopathic dilated cardiomyopathy (DCM) and to identify the scintigraphic predictors of the efficacy of cardiac resynchronization therapy (CRT).

The study comprised 63 patients with DCM and severe heart failure (NYHA class III–IV). Before CRT, all patients received gamma-scintigraphy with ^99mTc-methoxyisobutylisonitrile (^99mTc-MIBI) and with ¹²³I-β-methyl-iodophenyl pentadecanoic acid (¹²³I-BMIPP) for evaluation of myocardial perfusion and metabolism, respectively. Before and after 6 months of CRT, all patients underwent echocardiography study to assess cardiac hemodynamics.

After 6 months of CRT, patients were divided into two groups: group 1 comprised responders in whom LV end systolic volume (LVESV) decreased by ≥15 % (n = 39); group 2 comprised non-responders in whom LVESV decreased by <15 % (n = 24). Before CRT, LV pumping function did not significantly differ between groups. Significant differences were found in the following preoperative scintigraphic parameters: myocardial perfusion defect size [7.4 % (5.9; 13.2) % and 11.8 (8.8; 16.2) %, p < 0.05] and metabolic defect size [7.4 (4.4; 14.7) % and 8.8 (8.8; 17.6) %, p < 0.05]. Metabolic scintigraphy showed greater diagnostic efficacy in determining the indications for CRT compared with perfusion scintigraphy [areas under the ROC curves (AUC) of 0.722 and 0.612, respectively]. The best metabolic defect size threshold value of 7.35 % predicted CRT efficacy with the sensitivity and specificity rates of 77.8 and 66.7 %, respectively.

Data of metabolic scintigraphy may be useful for the integrated prediction of CRT efficacy.