Nonviable Myocardium Research Articles

Effect of primary pci in asymptomatic stemi patients presenting 12 to 48 hours of symptom onset, on myocardial viability assessed by spect tc 99m sestamibi scan epitome99

Abstract Background Guidelines on revascularization of asymptomatic stable STEMI patients presenting 12-48 hours of symptom onset are limited. We utilized TC-99mSestaMIBI scan to study the impact of primary PCI on myocardial viability by deriving myocardial salvage index (MSI) from area at risk (AAR), prior to revascularization and final infarct size (FIS) at follow up, in asymptomatic stable STEMI patients presenting between 12-48 hours of symptom onset to PCI. Purpose Evidence contributing lack of symptoms to a non-viable myocardium is lacking and it would be unethical to randomize patients with myocardial infarction (< 48 hours old) to a control arm or a non-intervention arm without evaluating the possibility of salvageable myocardium. Our study aims to inculcate evidence based management of late presenting stable asymptomatic STEMI patients. Methods We enrolled 141 patients presenting with STEMI (12-48 hours), from January 2021 to December 2023, who then underwent TC-99mSestaMIBI scan, followed by revascularization of IRA with 138 patients completing the designed study with follow-up scan at 3 months. Subjects were subcategorised into cohort A(12-24 hrs.), B(25-36 hrs.), and C(37-48 hrs.) according to the duration of symptom onset. Results A substantial MSI of > 0.50 was achieved by 36 %, 8% and 5 % of patients from cohort A, cohort B, and cohort C respectively. Although the AAR was comparable throughout cohorts, on post HOC analysis a statistically significant reduction in the final infarct size was seen among patients in cohort A vs C [Q = 4.72 (p = .00309)], while a reduction of FIS in cohort B and cohort C were obvious but statistically insignificant. Myocardial salvage index was smaller in late presenters, with no statistically significant difference among cohort B & cohort C [Q = 0.96 (p = .77697)]. Delaying the timing of Primary PCI from symptom onset was associated with larger AAR (R= - 0.01) & FIS (R= 0.35) although with a lower correlation coefficient. While evaluating MSI against timing of Primary PCI, a moderately negative (R= - 0.41) relation exists, indicating a linear correlation to reduced myocardial salvage Index with delay in the timing of primary PCI to symptom onset. Conclusion Asymptomatic stable STEMI patients presenting 12-24 hours of symptom onset to PCI, benefited from primary PCI with lesser final infarct size and larger MSI. Despite a comparable AAR across cohorts, MSI fell sharply among patients undergoing primary PCI 24-48 hours of symptom onset with a larger final infarct size, warranting viability guided revascularization. Although primary PCI improved final LVEF and MSI in patients with ischemic heart failure, parameter gain alone was insufficient in endeavoring a positive clinical impact.

Assessment of Myocardial Viability in Ischemic Cardiomyopathy With Reduced Left Ventricular Function Undergoing Coronary Artery Bypass Grafting.

We aim to provide a comprehensive review of the current state of knowledge of myocardial viability assessment in patients undergoing coronary artery bypass grafting (CABG), with a focus on the clinical markers of viability for each imaging modality. We also compare mortality between patients with viable myocardium and those without viability who undergo CABG. A systematic database search with meta-analysis was conducted of comparative original articles (both observations and randomized controlled studies) of patients undergoing CABG with either viable or nonviable myocardium, in EMBASE, MEDLINE, Cochrane database, and Google Scholar, from inception to 2022. Imaging modalities included were dobutamine stress echocardiography (DSE), cardiac magnetic resonance (CMR), single-photon emission computed tomography (SPECT), and positron emission tomography (PET). A total of 17 studies incorporating a total of 2317 patients were included. Across all imaging modalities, the relative risk of death post-CABG was reduced in patients with versus without viability (random-effects model: odds ratio: 0.42; 95% confidence interval: 0.29-0.61; p < 0.001). Imaging for myocardial viability has significant clinical implications as it can affect the accuracy of the diagnosis, guide treatment decisions, and predict patient outcomes. Generally, based on local availability and expertise, either SPECT or DSE should be considered as the first step in evaluating viability, while PET or CMR would provide further evaluation of transmurality, perfusion metabolism, and extent of scar tissue. The assessment of myocardial viability is an essential component of preoperative evaluation in patients with ischemic heart disease undergoing surgical revascularization. Careful patient selection and individualized assessment of viability remainparamount.

The impact of concomitant chronic total occlusion on clinical outcomes in patients undergoing transcatheter aortic valve replacement: a large single-center analysis.

Coronary artery disease (CAD) is a common finding in patients with severe aortic stenosis undergoing transcatheter aortic valve replacement (TAVR). However, the impact on prognosis of chronic total occlusions (CTOs), a drastic expression of CAD, remains unclear. We retrospectively reviewed 1,487 consecutive TAVR cases performed at a single tertiary care medical center. Pre-TAVR angiograms were analyzed for the presence of a CTO. At the time of TAVR, 11.2% (n = 167) patients had a CTO. There was no significant association between the presence of a CTO and in-hospital or 30-day mortality. There was also no difference in long-term survival. LV ejection fraction and mean aortic gradients were lower in the CTO group. Our analysis suggests that concomitant CTO lesions in patients undergoing TAVR differ in their risk profile and clinical findings to patients without CTO. CTO lesion per se were not associated with increased mortality, nevertheless CTOs which supply non-viable myocardium in TAVR population were associated with increased risk of death. Additional research is needed to evaluate the prognostic significance of CTO lesions in TAVR patients.

Angiographic Predictors of Viability During Intervention for a ST Elevation Myocardial Infarction.

This study aimed to identify angiographic features that would predict myocardial viability after coronary intervention for ST elevation myocardial infarction (STEMI). This retrospective study included patients who attended Sultan Qaboos University Hospital, Muscat, Oman, between January and December 2019 with a STEMI. A total of 72 patients (61 male; mean age = 54.9 ± 12.7 years) were included in the study; 11 patients had evidence of non-viability on echocardiography. There were 13 patients with viable myocardium and 3 with non-viable myocardium who had a myocardial blush grade (MBG) of 2 or lower. Similarly, 10 patients with viability and 1 with non-viable myocardium had thrombolysis in myocardial infarction (TIMI) flow of 2 or lower in the infarct related artery (IRA). However, none of these were statistically significant. The TIMI flow in the IRA at the end of the procedure correlated with the MBG. There were no clear angiographic features during primary angioplasty that could predict myocardial viability.

ACCURACY OF PATHOLOGIC Q WAVE ON ELECTROCARDIOGRAPHY TO PREDICT NON-VIABLE MYOCARDIUM

A prospective study was conducted to determine the diagnostic accuracy of Q wave on ECG in predicting the non-viable myocardium in patients with myocardial infarction, considering SPECT as the gold standard in the Department of Nuclear Cardiology, Ch. Pervaiz Elahi Institute of Cardiology (CPEIC), Multan, from June 2022 to June 2023. A total of 414 patients with myocardial infarction were included in the study. Demographic and clinical data such as age, gender, smoking history, diabetes, and hypertension were collected. Before the SPECT scan, 12 lead ECG was done in all patients to determine the pathologic Q wave. Pathologic Q-wave on ECG was found in 252 (60.87%) and not in 162 (39.13%) patients. Non-viable myocardium on SPECT was found in 231 (55.80%) and not in 183 (44.20%) patients. Pathologic Q-wave was 68.80% sensitive and 49.20% specific, with 63.10% PPV and 55.60% NPV compared to SPECT. This difference was statistically significant (P&lt;0.001). Development of pathologic Q wave on ECG was significantly associated with male gender (P =0.006), hypertension (P=0.008), and smoking (P=0.002). In conclusion, pathologic Q wave on ECG is a reliable tool for predicting non-viable myocardium in CAD patients.

Irreversible myocardial injury attenuates the benefits of sacubitril/valsartan in heart failure patients

BackgroundDespite the established benefits of angiotensin receptor-neprilysin inhibitor (ARNI) in heart failure with reduced ejection fraction (HFrEF) across various etiologies, there are controversies regarding the effects of ARNI in patients with irreversible myocardial injury. The aim of this study is to investigate the impact of irreversible myocardial injury on the benefits of ARNI treatment in patients with HFrEF, consisted of both ischemic and non-ischemic etiologies. Methods and resultsWe conducted a retrospective single-center study including 409 consecutive patients with HFrEF treated with ARNI between March 2017 and May 2020. Irreversible myocardial injury was defined as nonviable myocardium without contractile reserve, which suggests a limited potential for recovery of left ventricular function and geometry. At baseline, irreversible myocardial injury was observed in 129 (31.5%) patients. Composite outcome was cardiovascular death or hospitalization for heart failure, which occurred in 56 (43.4%) and 61 (21.8%) patients with and without irreversible myocardial injury, respectively. On multivariable analysis, irreversible injury presence, but not ischemic etiology, was an independent predictor of composite outcome (hazard ratio 2.16, 95% confidence interval 1.33–3.49). Mediation analysis revealed that the increased risk of the composite outcome due to irreversible myocardial injury was mediated by attenuated LV reverse remodeling (Z value = 2.02, P = 0.043). ConclusionsThe presence of irreversible myocardial injury was significantly associated with the response to ARNI treatment in patients with HFrEF, regardless of etiology.

Association of revascularization with mortality in ischemic left ventricular dysfunction

Abstract Background Revascularization in patients with left ventricular (LV) dysfunction has been a subject of ongoing uncertainty and conflicting results. This is further complicated by factors including viability, severity of LV dysfunction, and method of revascularization using percutaneous coronary intervention (PCI) versus coronary-artery bypass grafting (CABG). The purpose of this meta-analysis is to evaluate the association of coronary revascularization with mortality in patients with ischemic LV dysfunction. Methods A literature search was conducted for studies reporting on all-cause mortality after revascularization with PCI or CABG compared to optimal medical therapy (OMT) in patients with ischemic LV dysfunction. The search included the following databases: Ovid MEDLINE, EMBASE, Web of Science, and Google Scholar. The search was not restricted to time or publication status. Results A total of 21 studies with 6062 participants (2838 revascularized, 3224 on OMT) met inclusion criteria. Mean follow-up was 37 months (11-68 months), mean LV ejection fraction (EF) was 29%, mean age was 61, 85% of patients were male. Revascularization was significantly associated with lower all-cause mortality compared to patients on OMT (OR 0.57, 95% CI 0.46-0.71; p&amp;lt;0.01). The association was statistically significant regardless of severity of LV dysfunction or method of revascularization. Heterogeneity between subgroups was low and test for subgroup difference was not statistically significant by EF cutoff of 35% or by revascularization method (p=0.43, I2=0%; p=0.12, I2=59.7%). Subgroup analysis by viability demonstrated that revascularization was significantly associated with lower all-cause mortality compared to OMT for patients with viability and mixed cohorts with or without viability, but not patients without viability (OR 0.47, 95% CI 0.33-0.66; p&amp;lt;0.01; OR 0.57, 95% CI 0.38-0.84; p&amp;lt;0.01; OR 0.73, 95% CI 0.51-1.02; p=0.07). The effect size was larger in the subgroup with viable myocardium compared to mixed patients with viable or non-viable myocardium (Z=4.33 vs 2.79). Conclusions Revascularization in patients with ischemic LV dysfunction is associated with lower risk of all-cause mortality independent of severity of LV dysfunction or method of revascularization. Revascularization is not associated with lower risk of all-cause mortality in patients without evidence of viable myocardium.

CONTRAST ECHOCARDIOGRAPHY: CURRENT APPLICATIONS AND INNOVATIONS

The ability to opacify the left ventricle and delineate the endocardium after intravenous injection of microbubble ultrasound enhancing agents (UEAs) is of established value to quantify volumes and function in suboptimal unenhanced images, particularly in stress echocardiograms. However, applications other than quantitation of left ventricle structure and function are being used in myriads of other disease states for contrast enhanced left ventricular opacification. Contrast agents enable recording of Doppler velocity signals in patients with poor ultrasound transmission, providing estimates of aortic stenosis gradient and pulmonary artery pressures. Contrast echo is of value in detecting apical hypertrophic cardiomyopathy and accompanying apical aneurysms. Most importantly, ultrasound enhancing agents can identify apical and left atrial masses when they cannot be visualized in unenhanced images, and can distinguish thrombi from tumors by visualizing the vascularity inherent in tumors. Contrast agents distinguish trabecular from compacted myocardium in noncompaction syndrome, and hypertrabeculation with other abnormal conditions. A major potential application of UEAs is myocardial opacification, which can assist in identifying nonviable myocardium. Also, the delayed reappearance of myocardial perfusion after microbubble destruction identifies impaired contrary flow and can diagnose coronary stenosis. Innovative applications of ultrasound contrast agents currently under investigation, include visualizing the vaso vasorum to identify plaques and assess their vulnerability, and theranostic agents to deliver drugs and biologists and to assist in sonothrombolysis. It is anticipated that the role of ultrasound contrast agents will continue to increase in the future.

Viability and Outcomes With Revascularization or Medical Therapy in Ischemic Ventricular Dysfunction

In the Revascularization for Ischemic Ventricular Dysfunction (REVIVED-BCIS2) trial, percutaneous coronary intervention (PCI) did not improve outcomes for patients with ischemic left ventricular dysfunction. Whether myocardial viability testing had prognostic utility for these patients or identified a subpopulation who may benefit from PCI remained unclear. To determine the effect of the extent of viable and nonviable myocardium on the effectiveness of PCI, prognosis, and improvement in left ventricular function. Prospective open-label randomized clinical trial recruiting between August 28, 2013, and March 19, 2020, with a median follow-up of 3.4 years (IQR, 2.3-5.0 years). A total of 40 secondary and tertiary care centers in the United Kingdom were included. Of 700 randomly assigned patients, 610 with left ventricular ejection fraction less than or equal to 35%, extensive coronary artery disease, and evidence of viability in at least 4 myocardial segments that were dysfunctional at rest and who underwent blinded core laboratory viability characterization were included. Data analysis was conducted from March 31, 2022, to May 1, 2023. Percutaneous coronary intervention in addition to optimal medical therapy. Blinded core laboratory analysis was performed of cardiac magnetic resonance imaging scans and dobutamine stress echocardiograms to quantify the extent of viable and nonviable myocardium, expressed as an absolute percentage of left ventricular mass. The primary outcome of this subgroup analysis was the composite of all-cause death or hospitalization for heart failure. Secondary outcomes were all-cause death, cardiovascular death, hospitalization for heart failure, and improved left ventricular function at 6 months. The mean (SD) age of the participants was 69.3 (9.0) years. In the PCI group, 258 (87%) were male, and in the optimal medical therapy group, 277 (88%) were male. The primary outcome occurred in 107 of 295 participants assigned to PCI and 114 of 315 participants assigned to optimal medical therapy alone. There was no interaction between the extent of viable or nonviable myocardium and the effect of PCI on the primary or any secondary outcome. Across the study population, the extent of viable myocardium was not associated with the primary outcome (hazard ratio per 10% increase, 0.98; 95% CI, 0.93-1.04) or any secondary outcome. The extent of nonviable myocardium was associated with the primary outcome (hazard ratio, 1.07; 95% CI, 1.00-1.15), all-cause death, cardiovascular death, and improvement in left ventricular function. This study found that viability testing does not identify patients with ischemic cardiomyopathy who benefit from PCI. The extent of nonviable myocardium, but not the extent of viable myocardium, is associated with event-free survival and likelihood of improvement of left ventricular function. ClinicalTrials.gov Identifier: NCT01920048.

Evaluation of myocardial viability by a secondary delayed 99mTc-MIBI nuclear scanning in ST-elevation myocardial infarction patients with delay in referral and nonviable myocardium in the first scintigraphy: a preliminary cohort study.

In the management of ST-segment elevation myocardial infarction (STEMI), if the treatment has not been initiated within the first 24 h and the patient no longer exhibits any symptoms, the decision to begin revascularization therapy is based on myocardial viability. If the tissue is nonviable, current guidelines advise against further revascularization therapy; however, collateral vessels represent an alternative source of blood supply and may help the damaged tissue to resume function; though at first, this tissue may not be considered viable. Thus, in patients whose first myocardial perfusion scintigraphy (MPS) revealed nonviable myocardium, a secondary MPS to assess viability may be beneficial and alter the course of treatment strategies. This prospective cohort study was conducted on 30 STEMI patients referred to Mazandaran Heart Center. If no myocardial viability was found using 99mTc-MIBI MPS, the patient was referred for a secondary MPS after 3 months. In total, out of 30 patients, 3 became viable. There was no significant relationship between the viability of different Rentrop classes. Comparison of viability between patients with different numbers of occluded vessels showed no significant relationship. Three patients (17%) among 17 patients with Rentrop class nonzero became viable in the second MPS. Also, among four patients (13.3%) with Rentrop class three, one patient (25%) became viable and among seven patients (23.3%) with Rentrop class one, two patients (28.6%) became viable. Considering the results of this study, although nonsignificant, this subject requires further investigation to reach a definite conclusion.

Cardioprotective potential of mitochondria-targeted antioxidant, mito-TEMPO, in 5-fluorouracil-induced cardiotoxicity

PurposeThe mitochondria-targeted antioxidants (MTAs) are known to offer protection against mitochondrial oxidative stress. The recent evidences support their role in mitigating oxidative stress-induced diseases, including cancer. Therefore, this study investigated cardioprotective potential of mito-TEMPO against 5-FU-induced cardiotoxicity.MethodsMito-TEMPO was administered to male BALB/C mice (intraperitoneally, 0.1 mg/kg b.w. for 7 days) followed by intraperitoneal administration of 5- FU (12 mg/kg b.w. for 4 days). During this period, mito-TEMPO treatment was also continued. The cardioprotective potential of mito-TEMPO was assessed by evaluating cardiac injury markers, extent of non-viable myocardium and histopathological alterations. Mitochondrial functional status and mitochondrial oxidative stress were assessed in cardiac tissue. 8-OHdG expression and apoptotic cell death were assessed using immunohistochemical techniques.ResultsThe level of cardiac injury markers CK-MB and AST were significantly (P ≤ 0.05) decreased in mito-TEMPO pre-protected group which was further reflected in histopathology as decrease in the percentage of non-viable myocardial tissue, disorganization, and loss of myofibrils. Mito-TEMPO ameliorated mtROS, mtLPO and conserved mitochondrial membrane potential. Further, it had significantly (P ≤ 0.05) improved the activity of mitochondrial complexes and mitochondrial enzymes. A significant (P ≤ 0.05) increase in the level of mtGSH, activity of mitochondrial glutathione reductase, glutathione peroxidase, and mitochondrial superoxide dismutase was observed. A decreased expression of 8-OHdG and reduced apoptotic cell death were observed in mito-TEMPO pre-protected group.ConclusionMito-TEMPO effectively mitigated 5-FU-induced cardiotoxicity by modulating mitochondrial oxidative stress, hence may serve as a protective agent/adjuvant in 5-FU-based combinatorial chemotherapy.

Transcoronary electrophysiological parameters in patients undergoing elective and acute coronary intervention.

Percutaneous coronary intervention is performed routinely in the management of myocardial infarction with obstructive coronary disease, but intervention to arteries supplying nonviable myocardium may be harmful. It is important therefore to establish myocardial viability, and there is an unmet need in current clinical practice for real time viability assessment to aid in decision making. Transcoronary pacing to assess myocardial electrophysiological parameters may be a novel viability assessment technique which could be used in this regard. Coronary intervention was carried out according to standard departmental procedure with standard equipment. An exchange length coronary guidewire was passed into both target and reference coronary vessels and an over-the-wire balloon or microcatheter was used to insulate the guidewire and allow electrophysiological parameters to be assessed. Readings were obtained from all major epicardial vessels and substantial branches. At each position, an intracoronary electrocardiogram was recorded, and R wave amplitude was measured. Transcoronary pacing was then performed to establish threshold and impedance for each myocardial segment. A viability cardiac MRI scan was performed for each patient. A standard segmental model was used to determine viability in each segment using an 'infarct score' based on degree of late gadolinium enhancement. Studies were reported blinded to the electrical parameters obtained from the coronary guidewire. The primary outcome was the relationship between pacing threshold and myocardial segment infarct score. Secondary outcomes included the relationship between segmental infarct score and R wave height, and between segmental infarct score and pacing impedance. Data were collected on the feasibility of studying the coronary segments as well as safety. Sixty-five patients presenting with stable coronary artery disease or acute coronary syndromes to Leeds General Infirmary between September 2019 and August 2021 were included in the study. Electrophysiological parameters from segments with an infarct score of zero were obtained, with wide variances seen, with no significant difference in impedance or threshold in any territory. There was a significant difference in sensitivity for segments in the right coronary artery territory for both elective and acute patients. This likely relates to reduced myocardial mass in these territories. No significant association between infarct score and sensitivity, impedance or threshold were seen. This study has established intracoronary electrophysiological parameters in both normal myocardium and areas of myocardial scar. No reliable association was seen between impedance, threshold or R wave amplitude and degree of myocardial viability, contrasting with prior findings from our group and others. More work is therefore required to fully understand the role of transcoronary pacing in this setting.

Complementary Value of Tissue Doppler Imaging in Dobutamine Stress Echocardiography: A Prospective Cohort Study

Introduction: In patients with Coronary Artery Diseases (CAD), the presence of viable myocardium predicts the recovery of Left Ventricular (LV) systolic function after revascularisation. The identification of myocardial viability during dobutamine stress echocardiography is subjective and with observer bias. Tissue Doppler Imaging (TDI) echocardiography has opened new possibilities for non-invasive quantification of myocardial function by directly interrogating myocardial velocity with high temporal and spatial resolution. Aim: To determine the baseline regional myocardial and mitral annular Maximum Systolic Velocities (MSV) in patients with LV dysfunction and to compare the MSV values in viable and nonviable myocardium. Materials and Methods: In this prospective Cohort study, TDI of regional and annular LV myocardial velocities was performed at the baseline (at rest) in 352 patients with CAD and LV dysfunction who were referred for Dobutamine stress Echocardiography. Viability assessment by 2 Dimensional (2D) methods was done simultaneously using routine Dobutamine stress protocol. Patients were grouped in two groups based on the presence or absence of viability with 2D stress echocardiography. TDI velocities were compared in the two groups of patients with and without myocardial viability. Measurements of regional wall thickness, Ejection Fraction(EF) and Wall Motion Score Index (WMSI) were done to assess the regional and global LV function in these patients. Those patients who underwent revascularisation were subsequently assessed for functional recovery by 2D and TDI echocardiography before discharge from the hospital. Analyses were conducted using Statistical Package for Social Sciences(SPSS) version 16.0. Results: Among 352 patients studied (124 females and 228 males), mean age 58 years (range 36 to 75 years). A total of 243 patients (69%) with viable myocardium as per 2D echocardiography had higher cut-off Baseline Regional Maximum Systolic Velocity (BRMSV) &gt;0.03 m/s and baseline mitral annular systolic velocity &gt;0.06 m/s with high sensitivity and specificity compared to patients with severe contractile dysfunction and non-viable myocardium. Conclusion: Tissue doppler parameters like regional myocardial systolic and mitral annular velocities have shown significantly higher cut-off values in those patients with ischaemic and viable myocardium compared to non-viable myocardium.

Efficacy of Native T1 Mapping in differentiation between viable and non-viable myocardium in chronic ischemia

Efficacy of Native T1 Mapping in differentiation between viable and non-viable myocardium in chronic ischemia

Impact of Positron Emission Tomography Viability Imaging: Guided Revascularizations on Clinical Outcomes in Patients With Myocardial Scar on Single-Photon Emission Computed Tomography Scans.

Positron emission tomography (PET) viability scan is used to determine whether patients with a myocardial scar on single-photon emission computed tomography (SPECT) may need revascularization. However, the clinical utility of revascularization decision-making guided by PET viability imaging has not been proven yet. The purpose of this study was to investigate the impact of PET to determine revascularization on clinical outcomes. Between September 2012 and May 2021, 53 patients (37 males; mean age = 64 ± 11 years) with a myocardial scar on MIBI SPECT who underwent PET viability test were analyzed in this study. The primary outcome was a temporal change in echocardiographic findings. The secondary outcome was all-cause mortality. Viable myocardium was presented by PET imaging in 29 (54.7%) patients. Revascularization was performed in 26 (49.1%) patients, including 18 (34.0%) with percutaneous coronary intervention (PCI) and 8 (15.1%) with coronary artery bypass grafting. There were significant improvements in echocardiographic findings in the revascularization group and the viable myocardium group. All-cause mortality was significantly lower in the revascularization group than in the medical therapy-alone group (19.2% vs. 44.4%, log-rank P = 0.002) irrespective of viable (21.4% vs. 46.7%, log-rank P = 0.025) or non-viable myocardium (16.7% vs. 41.7%, log-rank P = 0.046). All-cause mortality was significantly lower in the PCI group than in the medical therapy-alone group (11.1% vs. 44.4%, log-rank P < 0.001). Revascularization improved left ventricular systolic function and survival of patients with a myocardial scar on SPECT scans, irrespective of myocardial viability on PET scans.

The association of collaterals with myocardial ischemia and viability in chronic total occlusions.

Collateral development in chronic total occlusions (CTO) is crucial to perfuse the distal myocardium and its angiographic evaluation is frequently used to assess the need for revascularization. We aimed to analyse the association between the presence of ischemia and hibernating myocardium, evaluated by cardiac [13N]NH3/2-[18F]FDG PET-CT, and the angiographic characterization of the collateral circulation. Prospective study including patients with a CTO who underwent a [13N]NH3 and, when deemed necessary, 2-[18F]FDG PET-CT. Well developed (WD) collaterals were defined as a concomitant angiographic Rentrop grade 3 and Werner collateral connection score 2 or 3, whereas the remaining as poorly developed (PD). 2% thresholds used to identify prognostic benefit of revascularization were applied: ischemia > 10% and hibernating myocardium > 7%. Fifty-nine patients (age 62.9±9.1 years, 58 male) were recruited, WD collaterals were present in 28 (47.5%). No significant differences were found in ischemia (WD 6.4±4.3 vs. PD 7.0±4.1, p = 0.64) and hibernation (WD 1.8±1.9 vs. PD 3.1±3.3, p = 0.18) scores. Most CTO territories demonstrated ischemia, but only 19 (46.3%) were associated with an area > 10% (WD 47.6% vs. PD 45.0%, p = 0.58). Scared non-viable myocardium was limited to 9 (15.3%) patients and was not associated with PD collaterals. Hibernating myocardium was frequent (54.2%), but just 6 (10.2%) CTO patients had an area of > 7% (WD 3.6% vs. PD 16.1%, p = 0.20). Collateral assessment by angiography has a poor association with the ischemic burden and hibernation state of CTO territories. Myocardial viability was present even in most CTO with angiographic PD collaterals.

Abstract 13119: Local Diastolic Dysfunction is Associated With Decreased Myocardial Viability in Patients With Heart Failure With Preserved Ejection Fraction

Introduction. Although impaired global diastolic function is a key determinant of heart failure with preserved ejection fraction (HFpEF), the impact of local diastolic dysfunction is less clear. Hypothesis. We analyzed the distribution and myocardial viability correlates of local diastolic dysfunction in patients with HFpEF. Methods. We enrolled 30 patients with HFpEF (NYHA class III, LVEF &gt;50%, E/e' &gt;15, and NT-proBNP &gt;300 pg/ml) who were referred to our center for cell transplantation. Before transplantation, all patients underwent electroanatomical mapping; viable myocardium was defined as unipolar voltage (UV) ≥8.27 mV and non-viable myocardium was defined as UV &lt;8.27 mV. Local diastolic function was assessed by a novel algorithm based on the measurement of local mechanical diastolic delay (LMD). At each sampling point, LMD was measured as timing difference between global end diastolic time (based on left ventricular volume) and maximum local diastolic time (based on local wall movement of the mapping point). Results. Most of the patients were male (77%), with a mean age of 62±10 years, creatinine of 1.05±0.40 mg/dl, E/e’ of 18.0±3.5, and LVEF of 57.6±6.1%. Using electroanatomical mapping we generated a total of 4820 mapping points in 30 patients. The mean local mechanical diastolic delay was 47±33 msec, and the coefficient of variation was 0.70. The distribution of local mechanical diastolic delay in points with preserved myocardial viability and decreased myocardial viability is presented in Figure 1. We found a significant inverse correlation between UV and LMD (r= -0.18, P=0.001). Conclusions. In patients with HFpEF, areas of local diastolic dysfunction are unevenly distributed and appear so correlate with areas of decreased myocardial viability. Figure 1. Distribution of LMD in areas of decreased and preserved myocardial viability.

Established and emerging roles for ultrasound enhancing agents (contrast echocardiography).

The ability to opacify the left ventricle and delineate the endocardium after intravenous injection of microbubble ultrasound enhancing agents is of established value to quantify volumes and function in suboptimal unenhanced images, particularly in stress echocardiograms. However, applications other than quantitation of left ventricle structure and function exist for contrast enhanced left ventricular opacification. Contrast agents enable recording of Doppler velocity signals in patients with poor ultrasound transmission, providing estimates of aortic stenosis gradient and pulmonary artery pressures. Contrast echo is of value in detecting apical hypertrophic cardiomyopathy and accompanying apical aneurysms. Most importantly, ultrasound enhancing agents can identify apical and left atrial masses when they cannot be visualized in unenhanced images, and can distinguish thrombi from tumors by visualizing the vascularity inherent in tumors. Contrast agents distinguish trabecular from compacted myocardium in noncompaction syndrome, and hypertrabeculation with other abnormal conditions. A major potential application of ultrasound enhancing agents is myocardial opacification, which can assist in identifying nonviable myocardium. Also, the delayed reappearance of myocardial perfusion after microbubble destruction identifies impaired contrary flow and can diagnose coronary stenosis. Innovative applications of ultrasound contrast agents currently under investigation, include visualizing the vaso vasorum to identify plaques and assess their vulnerability, and theranostic agents to deliver drugs and biologists and to assist in sonothrombolysis. It is anticipated that the role of ultrasound contrast agents will continue to increase in the future.

Do Patients With Non-Viable Myocardium From Ischemic Cardiomyopathy Benefit From Revascularization? A Systematic Review And Meta-Analysis

BackgroundMyocardial viability assessment is used to select patients who will derive the greatest benefit from revascularization. It remains controversial whether revascularization only benefits patients with ischemic cardiomyopathy who have viable myocardium. The objective of this meta-analysis was to compare mortality between patients with ischemic cardiomyopathy and non-viable myocardium who underwent revascularization and those who underwent medical therapy alone. MethodsThe MEDLINE database was searched using PubMed to retrieve studies published up to December 2021. Inclusion criteria were 1. studies that evaluated the impact of revascularization (revascularization group) versus medical therapy alone (control group) following myocardial viability assessment; 2. patients who had coronary artery disease that was amenable to coronary artery bypass grafting or percutaneous coronary intervention; and 3. patients who had non-viable myocardium. The main outcome measure was all-cause mortality. ResultsA total of 12 studies were included, evaluating 1363 patients with non-viable myocardium, of whom 501 patients underwent revascularization and 862 patients received medical therapy alone. There was a significant reduction in all-cause mortality (RR 0.76, 95 % CI: 0.62–0.93, I2 = 0) in the revascularization group compared to the control group. There was no association between the type of viability imaging modality and the risk of all-cause mortality (P-interaction = 0.58). ConclusionsThe findings of this meta-analysis suggest a benefit from revascularization compared to medical therapy in patients with ischemic cardiomyopathy despite the lack of myocardial viability.

Accuracy of Global Longitudinal and Territorial Longitudinal Strain in Determining Myocardial Viability in Comparison to Single-Photon Emission Computed Tomography in Out of Window Period Anterior Wall Myocardial Infarction Patients.

Background: To determine the accuracy of global longitudinal strain and territorial longitudinal strain in determining myocardial viability in comparison to single-photon emission computed tomography in out of window period anterior wall myocardial infarction patients.Methods: This was a single-center, prospective study carried out in a tertiary care center in northern India. All patients presenting with anterior wall myocardial infarction–out of window period without ongoing chest pain and akinetic left-anterior descending territory on echocardiography were recruited. All patients underwent strain echocardiography and the determination of both global longitudinal strain and territorial longitudinal strain within 12-48 hours of anterior wall myocardial infarction. In addition, all underwent single-photon emission computed tomography to determine the viability status of the anterior myocardium.Results: Fifty-one patients of anterior wall myocardial infarction–out of window period were enrolled and underwent strain imaging with speckle tracking and single-photon emission computed tomography for viability determination. Gobal longitudinal strain and territorial longitudinal strain were significantly reduced in patients with nonviable myocardium (P < .001). On receiver-operating curves, a gobal longitudinal strain of <10.45% had a sensitivity of 77.8% and specificity of 93.9% (AUC = 0.889) in predicting nonviability on single-photon emission computed tomography. Similarly, a territorial longitudinal strain of <7.60% had a sensitivity of 77.8% and specificity of 84.8% (AUC = 0.825) in predicting nonviability.Conclusions: Treatment strategies in patients presenting with anterior wall myocardial infarction, outside the window period is largely guided by the hemodynamic status and influenced by the viability status of the myocardium. Strain echocardiography using speckle tracking provides gobal longitudinal strain and territorial longitudinal strain, both of which have good sensitivity and specificity in predicting viability and can be performed safely and quickly in high-risk group of patients.