Evaluation Of Myocardial Viability Research Articles

Saved myocardium in acute ST-segment elevation myocardial infarction post-reperfusion: Analysis by cardiac magnetic resonance

To quantify by cardiovascular magnetic resonance the salvaged myocardium in the myocardium supplied by the infarct-related artery in reperfused and non-reperfused patients with a first ST-segment elevation myocardial infarction (STEMI). Twenty-five patients with a first STEMI (non-reperfused, ten patients; thrombolysis, ten patients; primary angioplasty, five patients) underwent cardiac magnetic resonance imaging 3 to 6 days after coronary angiography. Myocardial salvage and myocardial salvage index were quantified. Peak troponin values were lower in patients with primary angioplasty than in thrombolysis and non-reperfused patients (14,1 ng/ mL versus 515,4 ng/mL and 123,1 ng/mL, respectively; p < 0,007) and smaller infarct size (14,1 g versus 31,2 g and 31,5 g, respectively; p < 0,003). Myocardial salvage mass and myocardial salvage index were higher in patients with primary angioplasty than in thrombolysis and non-reperfused patients (27,4 g versus 4,7 g and 2,1 g, respectively; p < 0,003) and (65,2% versus 14,9% and 6,6%, respectively; p < 0,0001). The results of this study indicate the need to reassess the performance of coronary angioplasty and stent implantation in patients with a first STEMI, thrombolysis, and non-thrombolysis without prior myocardial viability studies. Cardiac magnetic resonance allows the quantification of salvaged myocardium and could be considered an emerging clinical application for the early evaluation of myocardial viability.

Cardiac magnetic resonance imaging for myocardial viability assessment: Optimizing surgical revascularization in ischemic heart disease.

Patients with poor ejection fraction undergoing coronary artery bypass grafting carry higher operative risk and have poor long-term survival. Cardiac magnetic resonance is a useful modality to assess viability which can identify patients likely to benefit most from revascularization. In this study, we aimed to assess the outcome in patients selected for surgical revascularization by cardiac magnetic resonance imaging and identify predictors associated with poor outcomes. The study included patients with severely impaired left ventricular function but with at least six viable segments. Patients requiring emergency surgery, undergoing combined procedures, or where cardiopulmonary bypass was required were excluded. Cardiac magnetic resonance was carried out both preoperatively and at six months postoperatively by the same radiologist in all cases. Late gadolinium enhancement was used for the evaluation of myocardial viability. Amongst a total of 493 segments studied, there were 89 (18.1%) non-viable, 117 (23.7%) hibernating and 287 (58.2%) viable segments. At six months, the number of non-viable segments changed from 89 (18.1%) to 97 (19.7%), with an increase in viable segments from 287 (58.2%) to 374 (75.8%) and a corresponding reduction of hibernating segments from 117 (23.7%) to 22 (4.5%). There was improvement in ejection fraction from 28 ± 5.54 to 37 ± 5.86 (p < 0.0001) in the entire cohort at six months. Overall mortality was 1 (3.2%). Preoperative left ventricular end-systolic volume had the strongest negative correlation with post-operative ejection fraction. Cardiac magnetic resonance aided revascularization is associated with low mortality. Preoperative left ventricular end-systolic volume is an important determinant of postoperative ejection fraction.

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.

Evaluation of myocardial viability in patients with myocardial ischemia reperfusion injury using the dual-energy CT myocardial blood pool imaging.

To evaluate myocardial viability in patients with myocardial ischemia reperfusion injury (MIRI) via dual-energy computed tomography myocardial blood pool imaging (DECT MBPI). Between September 2017 and January 2019, we prospectively recruited 59 patients with acute myocardial infarction (AMI) who developed MIRI after revascularization during invasive coronary angiography (ICA). Then, they received DECT MBPI, SPECT, and PET sequentially within 1 week after the onset of MIRI. A total of 1003 myocardial segments of 59 patients were recruited for this study. The iodine reduction areas and delayed enhancement areas were calculated by cardiac iodine map with SPECT rest myocardial perfusion imaging (MPI) + PET myocardial metabolism imaging (MMI) as reference criteria. The paired sample t-test was used to measure the difference of the myocardial iodine value. Cohen's Kappa analysis was used to test the consistency among different observers. ROC analysis was used to calculate the myocardial viability of DECT MBPI. ROC showed the AUCs of DECT MBPI iodine value to identify a normal myocardium, an ischemic myocardium, and an infarcted myocardium were 0.957, 0.900, and 0.906 (p < 0.001). The sensitivity, specificity, and accuracy of DECT MBPI in identifying an ischemic myocardium were 87.6%, 89.3%, and 97.9% (p < 0.001). The sensitivity, specificity, and accuracy of DECT MBPI in identifying an infarcted myocardium were 88.9%, 92.2%, and 98.6% (p < 0.001). The cutoff value for DECT MBPI to differentiate between an ischemic and a normal myocardium was 0.84 mg I/mL. The cutoff value for DECT MBPI to differentiate between an infarct and a normal myocardium was 2.01 mg I/mL. DECT MBPI can be used to assess myocardial viability in patients with MIRI with high sensitivity and specificity. • Dual-energy computed tomography myocardial blood pool imaging (DECT MBPI) can evaluate myocardial viability of myocardial ischemia-reperfusion injury (MIRI). • DECT MBPI is a non-invasive and timesaving method for evaluation on myocardial ischemia-reperfusion injury in patients with acute myocardial infarction after coronary intervention.

Cardiovascular positron emission tomography: established and emerging role in cardiovascular diseases.

Cardiac positron emission tomography (PET) imaging has established themselves firmly as excellent and reliable functional imaging modalities in assessment of the spectrum of coronary artery disease. With the explosion of technology advances and the dream of flow quantification now a reality, the value of PET is now well realized. Cardiac PET has proved itself as precise imaging modality that provides functional imaging of the heart in addition to anatomical imaging. It has established itself as one of the best available techniques for evaluation of myocardial viability. Hybrid PET/computed tomography provides simultaneous integration of coronary anatomy and function with myocardial perfusion and metabolism, thereby improving characterization of the dysfunctional area and chronic coronary artery disease. The availability of quantitative myocardial blood flow evaluation with PET provides additional prognostic information and increases diagnostic accuracy in the management of patients with coronary artery disease. Hybrid imaging seems to hold immense potential in optimizing management of cardiovascular diseases and furthering clinical research.

Management of Patients With Single-Ventricle Physiology Across the Lifespan: Contributions From Magnetic Resonance and Computed Tomography Imaging.

Cardiovascular magnetic resonance (CMR) and cardiac computed tomography (CCT) are robust cross-sectional imaging modalities that are increasingly being used to guide the diagnosis and management of those born with single-ventricle physiology. The purpose of this review is to acquaint the reader with the wide range of cross-sectional imaging applications that can be applied in this population. Illustrative examples of information provided by CMR and CCT are included, such as delineation of cardiac anatomy, measurement of ventricular volumetry, interrogation of vascular anatomy and flows, evaluation of myocardial viability, and exclusion of thromboembolic disease. Focus is placed on the appropriate selection and timing of advanced cardiac imaging modalities, and differentiations are made between establishedindications for imaging and emerging applications (such as 4-dimensional [4D] flow assessment and parametric imaging for identification of diffuse fibrosis using CMR). Potential CMR and CCT contributions in the selection of interventional strategies in the child and for surveillance of postoperative complications in the adult are highlighted. Furthermore, the importance of extracardiac cross-sectional imaging in the single-ventricle population is emphasized given the recognition that complications post-Fontan palliation are not limited to the cardiovascular system but will often include extracardiac manifestations of disease (such as hepatic disease or lymphatic abnormalities), While the value of CMR and CCT for contemporary clinical care of individuals born with single-ventricle physiology appears to be well-established, further research will be necessary to explore the impact of risk stratification using imaging biomarkers on clinical outcomes following Fontan palliation.

Myocardial Viability – An Important Decision Making Factor in the Treatment Protocol for Patients with Ischemic Heart Disease

Abstract Ischemic heart disease (IHD) affects &gt; 110 million individuals worldwide and represents an important contributor to the rise in the prevalence of heart failure and the associated mortality and morbidity. Despite modern therapies, up to one-third of patients with acute myocardial infarction would develop heart failure. IHD is a pathologic condition of the myocardium resulting from the imbalance in a given moment between its oxygen demands and the actual perfusion. Acute and chronic forms of the disease may potentially lead to extensive and permanent damage of the cardiac muscle. From a clinical point of view, determination of the still viable extent of myocardium is crucial for the therapeutic protocol – since ischemia is the underlying cause, then revascularization should provide for a better prognosis. Different methods for evaluation of myocardial viability have been described – each one presenting some advantages over the others, being, in the same time, inferior in some respects. The review offers a relatively comprehensive overview of methods available for determining myocardial viability.

Angiographic index of myocardial viability in patients with different duration of occlusive coronary lesion

INTRODUCTION. Evaluation of myocardial viability in chronic coronary occlusion determines the feasibility of revascularization of this zone.The OBJECTIVE was to evaluate the significance of the angiographic index in determining the viability of the myocardium at various times after occlusion of the coronary artery.METHODS AND MATERIALS. 156 patients with coronary artery disease (CAD) with chronic coronary occlusion according to coronary angiography (CG) were examined and treated during the period from 2012 to 2021. All patients underwent endovascular recanalization of chronic coronary occlusion. All patients were divided into 4 groups depending on the time of coronary occlusion (up to 3 months, 3-6 months, 6-9 months, more than 9 months) The results of recanalization were compared to the preoperative evaluation of myocardial viability based on the volume of collateral blood flow (Renrop score).RESULTS. The angiographic index of non-viable myocardium was highly specific from the first months in all observation groups (77, 94, 97, 97.5 %), however, its sensitivity had diagnostic value only in patients with occlusion duration of more than 6 months (80 % or more).CONCLUSION. The diagnostic value (sensitivity and specificity) of detecting non-viable myocardium based on retrograde collateral blood flow is significant for occlusion duration of more than 6 months. Refusal of revascularization based on the absence of retrograde blood flow during the first 6 months after coronary occlusion is not correct.

Cardiac Magnetic Resonance Tissue Characterization in Ischemic Cardiomyopathy.

Ischemic cardiomyopathy (ICM) is one of the most common causes of congestive heart failure. In patients with ICM, tissue characterization with cardiac magnetic resonance imaging (CMR) allows for evaluation of myocardial abnormalities in acute and chronic settings. Myocardial edema, microvascular obstruction (MVO), intracardiac thrombus, intramyocardial hemorrhage, and late gadolinium enhancement of the myocardium are easily depicted using standard CMR sequences. In the acute setting, tissue characterization is mainly focused on assessment of ventricular thrombus and MVO, which are associated with poor prognosis. Conversely, in chronic ICM, it is important to depict late gadolinium enhancement and myocardial ischemia using stress perfusion sequences. Overall, with CMR's ability to accurately characterize myocardial tissue in acute and chronic ICM, it represents a valuable diagnostic and prognostic imaging method for treatment planning. In particular, tissue characterization abnormalities in the acute setting can provide information regarding the patients that may develop major adverse cardiac event and show the presence of ventricular thrombus; in the chronic setting, evaluation of viable myocardium can be fundamental for planning myocardial revascularization. In this review, the main findings on tissue characterization are illustrated in acute and chronic settings using qualitative and quantitative tissue characterization.

18F-FDG PET in Myocardial Viability Assessment: A Practical and Time-Efficient Protocol.

We assessed image quality using a practical and time-efficient protocol for intravenous glucose loading and insulin injection before administration of 18F-FDG for PET myocardial viability evaluation in patients with ischemic cardiomyopathy (ICM), with and without type 2 diabetes mellitus. Methods: The metabolic preparation period (MPP) or optimal cardiac 18F-FDG uptake was determined from the time of intravenous infusion of 12.5 or 25 g of 50% dextrose to the time of 18F-FDG injection. Cardiac 18F-FDG image quality was evaluated according to a 5-point scoring system (from 5, excellent, to 1, nondiagnostic) by 2 independent observers. In cases of disagreement, consensus was achieved in a joint reading. Fifteen patients with ICM who underwent oral glucose loading and intravenous insulin administration served as a reference for MPP comparisons. Results: Fifty-nine consecutive patients (age, 63 ± 10 y; 48 men and 11 women) underwent rest 99mTc-tetrofosmin SPECT/CT and 18F-FDG PET/CT for the evaluation of myocardial viability. 18F-FDG image quality was scored as excellent in 42%, very good in 36%, good in 17%, fair in 3%, and nondiagnostic in 2%. When diabetic and nondiabetic patients were compared, the quality scores were excellent in 29% versus 76%, very good in 41% versus 18%, good in 24% versus 6%, fair in 4% versus 0%, and nondiagnostic in 2% versus 0%. The mean (±SD) quality score was 4.12 ± 0.95, and overall it was better in nondiabetic than in diabetic patients (4.71 ± 0.59 vs. 3.88 ± 0.96; P < 0.0001). Notably, the average MPP was significantly less with intravenous glucose loading than with oral glucose loading (51 ± 15 min vs. 132 ± 29 min; P < 0.0001), paralleled by higher insulin doses (6.3 ± 2.2 U vs. 2.0 ± 1.69 U; P < 0.001). Conclusion: Using a practical and time-efficient protocol for intravenous glucose loading and insulin administration before 18F-FDG injection reduces the MPP by 61% as compared with an oral glucose challenge and affords good-to-excellent image quality in 95% of ICM patients.

Acquisition, Processing, and Interpretation of PET 18F-FDG Viability and Inflammation Studies.

This article reviews the acquisition protocols and image interpretation for 18F-fluorodeoxyglucose (18F-FDG) imaging with positron emission tomography (PET) applied to the evaluation of myocardial viability and inflammation. Cardiac PET with 18F-FDG provides essential information for the assessment of myocardial viability and inflammation and is usually combined with PET perfusion imaging using 82Rb or 13N-ammonia. Viable myocardium maintains glucose metabolism which can be detected via the uptake of 18F-FDG by PET imaging. The patient is prepared for viability imaging by shifting the metabolism of the heart to maximize the uptake of glucose and hence of 18F-FDG. Comparison of the 18F-FDG and myocardial perfusion images allows distinction between regions of the myocardium that are hibernating and thus may recover function with intervention, from those that are infarcted. Increased glucose utilization in the inflammatory cells also makes 18F-FDG a useful imaging technique in conditions such as cardiac sarcoidosis. Here, suppression of normal myocardial uptake is essential for accurate image interpretation. 18F-FDG PET broadens the scope of information potentially available through a cardiac PET study. With careful patient preparation, it provides valuable insights into myocardial viability and inflammatory processes such as sarcoidosis.

Raman Spectroscopic Assessment of Myocardial Viability in Langendorff-Perfused Ischemic Rat Hearts.

Spontaneous Raman spectroscopy, which senses changes in cellular contents of reduced cytochrome c, could be a powerful tool for label-free evaluation of ischemic hearts. However, undetermined is whether it is applicable to evaluation of myocardial viability in ischemic hearts. To address this issue, we investigated sequential changes in Raman spectra of the subepicardial myocardium in the Langendorff-perfused rat heart before and during ligation of the left coronary artery and its subsequent release and re-ligation. Under 532-nm wavelength excitation, the Raman peak intensity of reduced cytochrome c at 747 cm−1 increased quickly after the coronary ligation, and reached a quasi-steady state within 30 min. Subsequent reperfusion of the heart after a short-term (30-min) ligation that simulates reversible conditions resulted in quick recovery of the peak intensity to the baseline. Further re-ligation resulted in resurgence of the peak intensity to nearly the identical value to the first ischemia value. In contrast, reperfusion after prolonged (120-min) ligation that assumes irreversible states resulted in incomplete recovery of the peak intensity, and re-ligation resulted in inadequate resurgence. Electron microscopic observations confirmed the spectral findings. Together, the Raman spectroscopic measurement for cytochrome c could be applicable to evaluation of viability of the ischemic myocardium without labeling.

Myocardial Viability Imaging using Manganese-Enhanced MRI in the First Hours after Myocardial Infarction.

Early measurements of tissue viability after myocardial infarction (MI) are essential for accurate diagnosis and treatment planning but are challenging to obtain. Here, manganese, a calcium analogue and clinically approved magnetic resonance imaging (MRI) contrast agent, is used as an imaging biomarker of myocardial viability in the first hours after experimental MI. Safe Mn2+ dosing is confirmed by measuring in vitro beating rates, calcium transients, and action potentials in cardiomyocytes, and in vivo heart rates and cardiac contractility in mice. Quantitative T1 mapping‐manganese‐enhanced MRI (MEMRI) reveals elevated and increasing Mn2+ uptake in viable myocardium remote from the infarct, suggesting MEMRI offers a quantitative biomarker of cardiac inotropy. MEMRI evaluation of infarct size at 1 h, 1 and 14 days after MI quantifies myocardial viability earlier than the current gold‐standard technique, late‐gadolinium‐enhanced MRI. These data, coupled with the re‐emergence of clinical Mn2+‐based contrast agents open the possibility of using MEMRI for direct evaluation of myocardial viability early after ischemic onset in patients.

Longitudinal Strain by Speckle Tracking during Dobutamine Stress Echocardiography in Suspected Coronary Arteries Disease

&#x0D; Background. Speckle tracking echocardiography (STE) provides valuable information about global and regional myocardial function. STE during dobutamine stress-echocardiography (DSE) enables more reliable ischemia diagnosis.&#x0D; The aim of the study was to evaluate STE feasibility as a DSE visualization method and its accuracy compared to coronary angiography (CAG) in the patients with moderate-to-high coronary arteries disease (CAD) risk.&#x0D; Methods. We prospectively examined 140 patients (84 [60.0%] men and 56 [40.0%] women) with suspected CAD in order to verify diagnosis and evaluate myocardial viability and coronary reserve.&#x0D; Results. Mean left ventricular ejection fraction (LVEF) was 54.4±15.8%. All the patients had normal blood pressure (BP) and heart rate (HR) during the test. There were no significant hemodynamics alterations during the test. There were no significant complications during DSE with only 15 (12.9%) cases of different relatively low grade supraventricular and ventricular arrhythmia, mainly transitory without interventions. There were 116 (82.9%) positive DSE results, of which 2 (1.72%) were false-positive. In 2 (8.3%) patients with negative DSE results, CAG revealed 1-vessel insignificant (50– 70%) lesions with developed collaterals (false-negative results). According to DSE and CAG results, 96 (82.3%) patients underwent revascularization interventions: 86 (89.6%) percutaneous coronary interventions (PCIs) and 10 (10.4%) coronary artery bypass grafting (CABG) surgery. Sensitivity and specificity of DSE with STE for primary CAD diagnosis according to the “golden standard” CAG results were 98.3% and 91.7%, respectively, with identical positive and negative predictive values and very high overall accuracy of the method (AUC = 0.98; OR = 627.0, p&lt;0.0001). Sensitivity and specificity of DSE with STE for defining indications for intervention and revascularization were 97.9% and 91.7%, respectively, with high overall accuracy (AUC = 0.95; OR = 564.0, p&lt;0.0001). Combined quantification of ΔGLS and ΔWMSI for primary CAD diagnosis showed significantly lower sensitivity 86.2%(p=0.0002)andspecificity80.4%(p=0.0064)withsignificantlylowerintegralmethodaccuracy(AUC0.83,p&lt;0.0001).&#x0D; Conclusions. DSE with STE as a visualization method is a safe and optimal method for ischemia diagnosis and evaluation of myocardial viability and coronary reserve in patients with suspected CAD. Given the lower ΔGLS and ΔWMSI accuracy compared to integral DSE with STE result evaluation, as well as frequent GLS growth in significant number of patients with definite positive test result, authors recommend evaluating integral test result rather than strain value.

Speckle tracking stress echocardiography: A valuable diagnostic technique or a burden for everyday practice?

Non-invasive screening for early diagnosis of coronary artery disease (CAD) represents a key element in the never-ending challenge to reduce cardiac death. Stress/rest electrocardiogram often lacks diagnostic accuracy, especially in asymptomatic patients, in fact the latest guidelines for the diagnosis and management of chronic coronary syndromes (CCS) stated the superiority of functional imaging techniques for the detection of subtle myocardial ischemia and the evaluation of myocardial viability (MV). Stress echocardiography is the most accessible and inexpensive imaging method for the study of CAD, either with pharmacological or with exercise provocative stress, based on visual wall-motion assessment. However, in some cases, such as small coronary lesions or microvascular angina, it loses its diagnostic power, therefore requiring a more sensitive approach. Accordingly, in the last years many authors investigated the possible additive value provided by the integration of an advanced but easy-to-obtain technique, that is speckle tracking imaging, to stress echocardiography, reaching promising results; nevertheless, its use is not included in the latest recommendations for CCS. The present review discusses the potential benefits from using a combination of speckle tracking and stress echocardiography for the early detection of myocardial ischemia and the assessment of MV and its suitability in different clinical scenarios, basing on the available evidence.

Delayed hyperenhancement obtained by non-contrast computed tomography following coronary angiography in patients of extracorporeal cardiopulmonary resuscitation

Abstract Background/Introduction Extracorporeal cardiopulmonary resuscitation (ECPR) has been reported to improve survival and neurologic outcome as compared to conventional CPR in refractory cardiac arrest. Although prognostic factors of these patients have been reported, predicting of outcome is difficult in real world. Recently, early evaluation of myocardial viability in acute myocardial infarction by non-contrast computed tomography (CT) post coronary angiography (CAG) has been reported. And myocardial contrast delayed enhancement obtained by this method related to higher risk of cardiac events. However, few studies have reported delayed enhancement on left ventricular wall findings in non-contrast CT after CAG in terms of patients performed ECPR. Purpose To investigate the impact of delayed hyperenhancement obtained by non-contrast CT following CAG in patients performed ECPR. Methods We investigated 79 patients treated by ECPR for refractory cardiac arrest regardless of whether in-hospital or out-hospital in our institute from Apr 2009 to Feb 2018. Thirty-two in these patients received non-contrast CT following CAG with ECPR were enrolled. All ECPR cases underwent VA-ECMO in the catheter laboratory using percutaneous procedure while maintaining conventional CPR. Non-ECG-gated and non-contrast CT was performed using a 64-row multidetector CT scanner. Results Survival rate was 18.8% in this cohort. There was no significant difference between survive and in-hospital death group in terms of patient characteristics, clinical time courses, initial blood samples and procedure characteristics. Only delayed hyperenhancement showed significant difference between 2 groups (p=0.04). All delayed hyperenhancements were detected in only in-hospital death group. Delayed hyperenhancement was detected in 12 cases (37.5%). Initial shockable rhythm was less common in cases with delayed hyperenhancement. Cardiac death tended to be more frequent in patients with delayed hyperenhancement. The major causes of death were bleeding (41.7%) and heart failure (33%). Conclusion(s) Delayed hyperenhancement in patients treated ECPR was strong predictor of in-hospital death. Image of delayed hyperenhancement Funding Acknowledgement Type of funding source: None

Does myocardial viability detection improve using a novel combined 99mTc sestamibi infusion and low dose dobutamine infusion in high risk ischemic cardiomyopathy patients?

Objective:Early identification of viable myocardium in ischemic cardiomyopathy (ICM) patients is essential for early intervention and better clinical outcome. 99mTechnetium (99mTc) sestamibi gated myocardial perfusion imaging (gMPI) is a well-established technique for myocardial viability evaluation. Detection of potentially viable segments is a predictor of hibernating myocardium. ICM patients with hibernation have a better prognosis after revascularization. We used a novel infusion technique to determine better viability detection preoperatively in challenging situations. Like thallium, does prolonged availability of sestamibi in circulation with additional low dose dobutamine steady infusion (DS Inf) facilitate improved myocardial viability?Methods:A total of 58 ICM patients with infarct and left ventricular ejection fraction (LVEF) <45% underwent 99mTc sestamibi bolus injection followed by slow intravenous infusion single-photon emission computed tomography (SPECT) using a 2 day protocol. After acquiring the second set of 99mTc sestamibi infusion images, a third SPECT gMPI was performed during DS Inf.Results:A 17-segment myocardial model was used; 52 of 58 patients (548/986 segments) demonstrated perfusion defects (nonviable myocardium) on bolus study. Only 24 patients demonstrated viable segments by standard bolus imaging protocol. The slow MIBI infusion study demonstrated 158 viable segments (12 ICM patients), while combined infusion (99mTc sestamibi+DS Inf) exhibited an additional 6 patients with improved myocardial viability. Thus, 18 high risk patients benefited by this novel infusion technique to demonstrate viable myocardium on SPECT. There was a significantly higher sensitivity (p=0.05) and positive predictive value (p=0.01) in viability identification with the combined DS Inf technique. In dysfunctional segments, the rate of concordance for detecting viability between infusion and bolus techniques was 65%. Paired t test showed statistically significant improvement in viability detection with combined infusion compared to the bolus study (p=0.001).Conclusion:This novel infusion technique was shown to be feasible and incremental in viability detection in ICM patients with severe left ventricular dysfunction. It is a robust tool to guide revascularization, in high risk ICM patients. This study also showed that patients with large transmural MI demonstrated no significant improvement in myocardial perfusion status using either protocol.

Assessment of viable myocardium by nitrate-augmented technetium-99m sestamibi myocardial perfusion imaging

Objective The aim of this study was to assess the role of nitrate-augmented technetium-99m (99mTc) sestamibi imaging in the evaluation of viable myocardium in patients who had ischemic heart disease with depressed left ventricle (LV) systolic function. Background In the setting of acute myocardial infarction, stunning can occur, which is the persistent LV dysfunction following opening of the occluded coronary artery; recovery of function occurs usually within months. In the setting of chronic LV dysfunction, the pathophysiology underlying the dysfunction is referred to as myocardial hibernation. Various imaging techniques have been introduced to detect viability and discriminate this from scar tissue. Patients and methods Between November 2015 and November 2016, 100 patients with a history of myocardial infarction 'functional class II and III' or/and LV dysfunction were included in this multicenter prospective study. All patients underwent 99mTc sestamibi myocardial perfusion imaging under both rest and rest with nitrate conditions. Results Nitrates improved viability detection by myocardial perfusion imaging in patients with depressed LV systolic function. There was significant decrease in the total perfusion defect in rest with nitrate study in comparison with the rest study (P = 0.006). Conclusion In patients with chronic ischemic heart disease with depressed LV systolic function, the use of nitrate-augmented Tc-99m sestamibi protocol in cardiac single photon emission computed tomography imaging results in improved detection of viable but hypoperfused segments. It is a good indicator for differentiating viable tissues from the scar.

Evaluation of myocardial viability in myocardial infarction patients by magnetic resonance perfusion and delayed enhancement imaging.

Cardiovascular magnetic resonance imaging (CMR) has been established as amodality to detect myocardial viability. The aim of this study was to evaluate myocardial viability by observing transmural extent of infraction and microvascular perfusion level. We performed CMR in 30myocardial infarction (MI) patients within 7-10days. At the 6‑month follow-up, CMR was used to evaluate the impact of abnormal reperfusion and observe the transmural extent of infraction on recovery of function. The left ventricle was divided into 16segments using the American Heart Association classification. Infarcts were detected in 202 of the 480 segments (42%) by delayed enhancement magnetic resonance imaging (DE-MRI). According to first-pass myocardial perfusion, abnormal perfusion was detected in 278 of 480 segments (60%), reduced perfusion was identified in 173 of 278 (62%), and perfusion defects in 105 of 278 segments (38%). The results showed that the segments with abnormal perfusion were larger than in DE-MRI (P < 0.05), indicating that the area of abnormal perfusion segments extend significantly beyond the region of infarction. Microvascular perfusion with an infarcted region was lower compared to non-infarcted segments (P < 0.05). The extent of myocardial hyperenhancement correlated inversely with microvascular perfusion (P < 0.05). Segments with severe microvascular perfusion and >75% transmural infarction on the 7‑ to 10-day scan had markedly increased at the 6‑month follow-up (P < 0.01), indicating alack of recovery of cardiac function. DE-MRI combined with microvascular perfusion may be effective to detect viable myocardium in patients with MI and may provide ameans of predicting whether revascularization will be effective.

Label-free Evaluation of Myocardial Infarct in Surgically Excised Ventricular Myocardium by Raman Spectroscopy

Understanding the viability of the ischemic myocardial tissue is a critical issue in determining the appropriate surgical procedure for patients with chronic heart failure after myocardial infarction (MI). Conventional MI evaluation methods are; however, preoperatively performed and/or give an indirect information of myocardial viability such as shape, color, and blood flow. In this study, we realize the evaluation of MI in patients undergoing cardiac surgery by Raman spectroscopy under label-free conditions, which is based on intrinsic molecular constituents related to myocardial viability. We identify key signatures of Raman spectra for the evaluation of myocardial viability by evaluating the infarct border zone myocardium that were excised from five patients under surgical ventricular restoration. We also obtain a prediction model to differentiate the infarcted myocardium from the non-infarcted myocardium by applying partial least squares regression-discriminant analysis (PLS-DA) to the Raman spectra. Our prediction model enables identification of the infarcted tissues and the non-infarcted tissues with sensitivities of 99.98% and 99.92%, respectively. Furthermore, the prediction model of the Raman images of the infarct border zone enabled us to visualize boundaries between these distinct regions. Our novel application of Raman spectroscopy to the human heart would be a useful means for the detection of myocardial viability during surgery.