Correlation of the Myocardial Viability Score with Left Ventricular Ejection Fraction in Patients after Revascularization

Background. Coronary artery disease (CAD) is one of the main causes of cardiovascular death. The severity of CAD is determined by the left ventricular (LV) dysfunction which is caused by coronary atherosclerosis. The possibility of restoring functional capacity of the heart (ejection fraction (EF)) depends on hibernating volume of the myocardium which is a pitfall in revascularization. The aim. To assess the correlation between the score of the viable myocardium (VM) and EF with systolic dysfunction and preserved LVEF in patients after coronary artery bypass grafting (CABG). Material and methods. To implement the set clinical tasks, 62 patients with CAD with preserved systolic function and systolic dysfunction were examined, 35 (56%) patients had heart failure with an EF of 49% (group 2) and less. Twenty-seven (44%) patients had preserved ventricular function of 50% or more (group 1). The mean age of the subjects was 59.6 ± 8.2 years. Five (8.0%) patients denied myocardial infarction. Myocardial scintigraphy was performed on Infinia Hawkeye all purpose imaging system (GE, USA) with integrated CT. The studies were performed in SPECT and SPECT/CT with ECG synchronization (gated SPECT) modes. 99mTc-MIBI with an activity of 555–740 MBq was used. Myocardial scintigraphy was performed in the course of treatment (before CABG and after CABG) according to the One Day Rest protocol. A total of 124 scintigraphic studies were performed. Results and discussion. Samples of the studied patients “before” and “after” treatment were compared using Wilcoxon matched-pairs test. In group 1 in patients with EF ≥ 50% the score of VM increased after CABG with values from 81.7 CI 95% [78.5; 84.9] to 86.9 CI 95% [84.4; 89.3]. However, the EF itself before and after treatment remained the same or slightly decreased amounting to 54.9 CI 95% [50.8; 59.1] and 52.5 CI 95% [48.6; 56.3]. In group 2 in patients with EF ≤ 49% the amount of VM increased after CABG with values from 59.9 CI 95% [54.9; 64.8] to 65.9 CI 95% [60.2; 71.6] (p = 0.00005). However, the EF itself before and after treatment remained the same, amounting to 28.9 CI 95% [24.8; 32.9] and 31.1 CI 95% [26.8; 35.5] (p = 0.19). Conclusions. Myocardial viability in both study groups significantly improved, given the high statistical reliability of the results, although LVEF either remained unchanged or changed slightly. Improvement of static parameters (wall perfusion) also confirms positive effect of revascularization with constant dynamic parameters (EF, end-diastolic volume) or statistically insignificant changes thereof. There is no direct correlation between VM and EF.

401 Myocardial viability and ischaemia assessment in chronic coronary total occlusions according to collaterals distribution: a retrospective analysis

Aims Whether CTO-PCI (chronic total occlusions—percutaneous coronary intervention) offers clinical benefit over optimal medical therapy is still a matter of debate. Viability and ischaemia assessment could improve selection of candidates to PCI. Traditionally, well-developed collaterals are considered a marker of myocardial viability in CTO territory. Current literature offers few data concerning the relationship between viability/ischaemia and collaterals distribution. Methods and results We retrospectively analysed the Cardiovascular Magnetic Resonance (CMR) studies and coronary angiographies of patients with at least one CTO referred at Humanitas Research Hospital between June 2009 and September 2020. We included 131 patients who underwent CMR with LGE assessment; of them, 111 (85%) underwent stress-CMR with adenosine. AHA segments (16 segment/patient for a total of 2096 segment assessed) were assessed on three short axis projection and scored for WMSI on cine images, for the presence of ischaemia on first pass perfusion, and for viability on LGE images. Viability was defined as LGE transmurality ≤50% and WMSI (wall motion score index) >1. Patients were divided in three groups according to collaterals distribution at coronary angiography: Patients with TD collaterals were more likely to have viable segments in the CTO-territory (90% of the segments in TD, 76% in WD, and 71% in PD, coeff. 0.107, P < 0.001). No statistically significant differences were found between groups as regard the amount of ischaemic segments (61% of the segments in TD, 65% in WD, and 60% in PD, P = 0.189). Conclusions The presence of myocardial viability is slightly associated with the degree of coronary collateralization at coronary angiography while the amount of ischaemia is not. Stress CMR should be considered in CTO patients before a reopening attempt.

Myocardial Viability, Functional Status, and Collaterals of Patients With Chronically Occluded Coronary Arteries

Objective: Viability and functional assessments are recommended for indication and intervention for chronic coronary total occlusion (CTO). We aimed to evaluate myocardial viability and left ventricular (LV) functional status by using cardiovascular magnetic resonance (CMR) and to investigate the relationship between them and collaterals in patients with CTO.Materials and Methods: We enrolled 194 patients with one CTO artery as detected by coronary angiography. Patients were scheduled for CMR within 1 week after coronary angiography.Results: A total of 128 CTO territories (66%) showed scar based on late gadolinium enhancement (LGE) imaging. There were 1,112 segments in CTO territory, while only 198 segments (18%) subtended by the CTO artery showed transmural scar (i.e., >50% extent on LGE). Patients with viable myocardium had higher LV ejection fraction (LVEF) (56.7 ± 13.5% vs. 48.3 ± 15.4%, p < 0.001) than those with transmural scar. Angiographically, well-developed collaterals were found in 164 patients (85%). There was no significant correlation between collaterals and the presence of myocardial scar (p = 0.680) or between collaterals and LVEF (p = 0.191). Nevertheless, more segments with transmural scar were observed in patients with poorly-developed collaterals than in those with well-developed collaterals (25 vs. 17%, p = 0.010).Conclusion: Myocardial infarction detected by CMR is widespread among patients with CMO, yet only a bit of transmural myocardial scar was observed within CTO territory. Limited number of segments with transmural scar is associated with preserved LV function. Well-developed collaterals are not related to the prevalence of myocardial scar or systolic functioning, but could be related to reduce number of non-viable segments subtended by the CTO artery.

USE OF DOBUTAMINE STRESS ECHOCARDIOGRAPHY TO ASSESS MYOCARDIAL VIABILITY BEFORE PCI IN TOTAL OCCLUSION OF CORONARY ARTERY IN A TERTIARY CARE CENTRE

Dobutamine stress echocardiography has significant advantages in our country due to its wide availability, portability, low cost and safety.This study was conducted with the aim to assess myocardial viability by Dobutamine Stress Echocardiography (DSE) before PCI in total occlusion of coronary artery.This study confirms that a biphasic response to dobutamine is highly predictive of postoperative recovery of regional contractile function (100% at 6th week follow-up). This studies provide evidence that, at low doses, inotropic stimulation with P- receptor agonists will result in an increase in LV function in areas of viable myocardium but not in areas of myocardial necrosis.

Incremental Value of Left Ventricular Mechanical Dyssynchrony Assessment by Nitrogen-13 Ammonia ECG-Gated PET in Patients With Coronary Artery Disease

Background: Phase analysis is a technique used to assess left ventricular mechanical dyssynchrony (LVMD) in nuclear myocardial imaging. Previous studies have found an association between LVMD and myocardial ischemia. We aim to assess the potential diagnostic value of LVMD in terms of myocardial viability, and ability to predict major adverse cardiac events (MACE), using Nitrogen-13 ammonia ECG-gated positron emission tomography (gPET).Methods: Patients with coronary artery disease (CAD) who underwent Nitrogen-13 ammonia and Fluorine-18 FDG myocardial gPET were enrolled, and their gPET imaging data were retrospectively analyzed. Patients were followed up and major adverse cardiac events (MACE) were recorded. The Kruskal-Wallis test and Mann-Whitney U test were performed to compare LVMD parameters among the groups. Binary logistic regression analysis, receiver operating characteristic (ROC) curve analysis, and multiple stepwise analysis curves were applied to identify the relationship between LVMD parameters and myocardial viability. Kaplan–Meier survival curves and the log-rank test were used to look for differences in the incidence of MACE.Results: In total, 79 patients were enrolled and divided into three groups: Group 1 (patients with only viable myocardium, n = 7), Group 2 (patients with more viable myocardium than scar, n = 33), and Group 3 (patients with less viable myocardium than scar, n = 39). All LVMD parameters were significantly different among groups. The median values of systolic phase standard deviation (PSD), systolic phase histogram bandwidth (PHB), diastolic PSD, and diastolic PHB between Group 1 and Group 3, and Group 2 and Group 3 were significantly different. A diastolic PHB of 204.5° was the best cut-off value to predict the presence of myocardial scar. In multiple stepwise analysis models, diastolic PSD, ischemic extent, and New York Heart Association (NYHA) classification were independent predictive factors of viable myocardium and myocardial scar. The incidence of MACE in patients with diastolic PHB > 204.5° was 25.0%, higher than patients with diastolic PHB <204.5° (11.8%), but the difference was not significant.Conclusions: LVMD generated from Nitrogen-13 ammonia ECG-gated myocardial perfusion imaging had added diagnostic value for myocardial viability assessment in CAD patients. LVMD did not show a definite prognostic value.