The value of cardiac sympathetic activity and mechanical dyssynchrony as cardiac resynchronization therapy response predictors: comparison between patients with ischemic and non-ischemic heart failure

The Value of Stress-Gated Blood Pool SPECT in Predicting Early Postoperative Period Complications in Ischemic Cardiomyopathy Patients: Focus on Mechanical Dyssynchrony

(1) Objective: The objective of this study was to assess the prognostic value of stress-gated blood pool SPECT (GBPS) estimates in patients with ischemic cardiomyopathy (ICM) in the early postoperative period. (2) Methods: A total of 57 patients (age 59.7 ± 6.6, 47 men) with ICM and LV ejection fraction (30 [27.5; 35]%) were enrolled in the study. Before surgical treatment, all patients underwent GBPS (rest-stress, dobutamine doses of 5/10/15 µg/kg/min). Stress-induced changes in left ventricular (LV) ejection fraction, peak ejection rate, volumes, and mechanical dyssynchrony (phase histogram standard deviation, phase entropy (PE), and phase histogram bandwidth) were estimated. Two-dimensional transthoracic echocardiography was performed baseline. Serum levels of NT-proBNP were analyzed with enzyme-linked immunoassay. (3) Results: After surgical treatment, patients were divided into two groups, one, with death, the need for an intra-aortic balloon pump (IABP) or/and inotropic support with a stay in the intensive care unit for more than two days and two, without complications in the early postoperative period (EPOP). Complicated EPOP (CEPOP) was observed in 17 (30%) patients (death-2, IABP-4, extra inotropic support in intensive care unit-11), and 40 patients had no complications (NCEPOP). GBPS showed differences in LV EDV (mL) (321 [268; 358] vs. 268 [242; 313], p = 0.02), LV ESV (mL) (242 [201; 282] vs. 196 [170; 230], p = 0.005), and stress-induced changes in PE (1 (-2; 3) vs. -2 (-4; 0), p = 0.02). Aortic cross-clamp time and stress-induced changes in PE between rest and dobutamine dose of 10 µg/kg/min were the only independent predictors of CEPOP. An increase in LV entropy ≥ 1 on the dobutamine dose of 10µg/kg/min in comparison to rest investigation showed AUC = 0.853 (sensitivity = 62%, specificity = 90%, PPV = 71%; NPV = 85%; p < 0.0001). Conclusion: Stress-induced changes in PE obtained during low-dose dobutamine GBPS are associated with a complicated course of the early postoperative period after surgical treatment for ICM.