Myocardial Viability Studies Research Articles

Controversias en la revascularización y el estudio de viabilidad miocárdica en el síndrome coronario crónico

The broad spectrum of patients with chronic coronary syndrome and the controversies in diagnosis and treatment pose a major challenge in clinical decision making. Concerning the diagnosis, the utility of myocardial viability study has been questioned by recent clinical trials. Regarding the therapeutic approach, in patients with simple coronary disease, percutaneous revascularization has proved its utility in anginal symptoms relieve, but the evidence regarding a prognostic benefit is contradictory. In complex coronary disease, coronary artery bypass grafting surgery has reported better results than percutaneous intervention. Besides, surgical revascularization has demonstrated a reduction in cardiovascular events over medical treatment in patients with ischemic left ventricular dysfunction. In this review we critically analyse the current evidence on viability study and myocardial revascularization in patients with chronic coronary syndrome.

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.

Fluorine 18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography Cardiac Viability Risk Stratification in Comparison with EuroSCORE II for Revascularization in Patients with Left Ventricular Dysfunction.

Diagnostic value of fluorine 18-fluorodeoxyglucose positron emission tomography/computed tomography (F18-FDG PET/CT) in the assessment of myocardial viable segments is well known; hence, it can identify patients with left ventricular (LV) systolic dysfunction who may benefit from revascularization. The presence of significant myocardial viable segments before revascularization will offer better prognosis with reduced mortality and morbidity. However, the usage of F18-FDG PET/CT myocardial viability study in the presurgical risk stratification is limited. The objective of the study is to predict perioperative mortality with hibernating viable myocardial (HVM) segments established by F18-FDG PET/CT in comparison with EuroSCORE II in patients with LV dysfunction undergoing coronary artery bypass grafting surgery. A prospective, observational study included 75 patients of chronic ischemic coronary artery disease with ejection fraction ≤40%. Tc-99m sesta-methoxyisobutylisonitrile myocardial perfusion single photon emission CT/CT and myocardial viability with F18-FDG PET/CT at rest were performed. Mortality risk stratification was done according to the EuroSCORE II. Patients were followed for post-coronary artery bypass graft surgery (CABG) 30-day mortality. Mortality observed by HVM segment groups were compared with EuroSCORE II predicted mortality. Receiver operating curve for 30-day mortality prediction with HVM segments and EuroSCORE II was constructed. It showed that a cutoff of <4 HVM segments (area under the curve [AUC] = 0.7) had a sensitivity of 85%, whereas EuroSCORE II (AUC = 0.4) had only 28.6% sensitivity. EuroSCORE II underestimated perioperative risk in patients with <4 viable segments, that is 5 times higher risk was observed in patients with <4 viable segments. HVM segments established by F18-FDG PET/CT had independently predicted mortality postoperatively. Hence, including F18-FDG PET/CT for viability assessment along with EuroSCORE II in preoperative risk assessment for revascularization by CABG in patients with LV dysfunction provided better risk stratification.

Qualitative Perfusion Assessment of Myocardial Viability Study in Patients Who Cannot Stop Long-acting Nitrate: Serial Case Reports

The information of myocardial viability status is important to decide the management of CAD. Myocardial viability study (VS) with short-acting nitrate (SAN)-added is recommended to perform inpatient with CAD before revascularization therapy. This study aims to determine whether there are differences in the perfusion results of myocardial viability studies with Long-acting nitrate (LAN) and those with added SAN. Three patients with CAD were referred to our department for myocardial VS to determine the treatment choice. Long-acting nitrate (LAN) was consumed regularly every day and not allowed to be stopped due to the symptomatic chest pain. Patients underwent two myocardial perfusion VS, the first study with continuing the daily routine LAN only and the second one with SAN-added to the daily routine LAN. VS was analyzed qualitatively. The result of this study, no significant perfusion difference between LAN treatment only and SAN-added studies, it is possible the LAN regular dose alone is sufficient to create a vasodilating effect on the arteries without the need for addition of SAN. Conclusion, patients who take LAN routinely, VS might be performed without the need to take additional vasodilator prior to radiopharmaceutical injection.Keywords: coronary artery disease; myocardial perfusion imaging; revascularization therapy; viability study

Second Wave of COVID-19 Pandemic in Malaysia and the Impact on Nuclear Cardiology Services: An Institutional Experience

Introduction: Nuclear cardiology applying radioactive tracer and hybrid imaging techniques are able to provide information needed to detect and evaluate ischaemic heart diseases. In our centre, nuclear cardiology services involving stress and rest myocardial perfusion scans and viability studies contribute about 40% of overall scan workload. The second wave of COVID- 19 pandemic in Malaysia announced by the end of February 2020 has affected nuclear cardiology services.Objectives: Our aims were to determine the impact of COVID-19 pandemic second wave on the nuclear cardiology imaging studies performed as well as to ascertain crucial institutional experience especially unavoidable problem and adjustment during the period.Methods: A review of Technetium-99m tetrofosmin radiopharmaceutical dispensing data and scan records for 1st February to 31st August 2019 and 2020 was conducted at Nuclear Medicine Department, Hospital Kuala Lumpur. Figures were compiled and statistical analysis done. Survey and focus discussion conducted involving nuclear medicine physicians, pharmacists and physic officers to identify the main difficulty faced and most important Job-adapting measure taken.Results: A total of 1109 cardiac radiopharmaceutical doses dispensed during the studied period but were less when compared to 1342 doses dispensed last year. Significant reduction was noted in April and May 2020 with only 69 and 67 cases respectively in comparison with monthly average of 192 cases in 2019. Although some scan appointments were postponed to avoid the usual waiting area congestions, the main difficulty faced was Technetium-99m generator supply disruption with limited production in Europe and international transportation restriction. Implementing infection control standard operating procedure (SOP) instructions as part of routine work practice with emphasis of time, distance and shielding concept was the most important Job-adapting measure.Conclusion: Nuclear cardiology services were affected by the second wave of COVID-19 pandemic locally. Main problem ascertained was disruption of radioactive supply. Most important adjustment was infection control SOP implementation.International Journal of Human and Health Sciences Supplementary Issue: 2021 Page: S25

Data-driven, projection-based respiratory motion compensation of PET data for cardiac PET/CT and PET/MR imaging

BackgroundRespiratory patient motion causes blurring of the PET images that may impact accurate quantification of perfusion and infarction extents in PET myocardial viability studies. In this study, we investigate the feasibility of correcting for respiratory motion directly in the PET-listmode data prior to image reconstruction using a data-driven, projection-based, respiratory motion compensation (DPR-MoCo) technique. MethodsThe DPR-MoCo method was validated using simulations of a XCAT phantom (Biograph mMR PET/MR) as well as experimental phantom acquisitions (Biograph mCT PET/CT). Seven patient studies following a dual-tracer (18F-FDG/13N-NH3) imaging-protocol using a PET/MR-system were also evaluated. The performance of the DPR-MoCo method was compared against reconstructions of the acquired data (No-MoCo), a reference gate method (gated) and an image-based MoCo method using the standard reconstruction-transform-average (RTA-MoCo) approach. The target-to-background ratio (TBRLV) in the myocardium and the noise in the liver (CoVliver) were evaluated for all acquisitions. For all patients, the clinical effect of the DPR-MoCo was assessed based on the end-systolic (ESV), the end-diastolic volumes (EDV) and the left ventricular ejection fraction (EF) which were compared to functional values obtained from the cardiac MR. ResultsThe DPR-MoCo and the No-MoCo images presented with similar noise-properties (CoV) (P = .12), while the RTA-MoCo and reference-gate images showed increased noise levels (P = .05). TBRLV values increased for the motion limited reconstructions when compared to the No-MoCo reconstructions (P > .05). DPR-MoCo results showed higher correlation with the functional values obtained from the cardiac MR than the No-MoCo results, though non-significant (P > .05). ConclusionThe projection-based DPR-MoCo method helps to improve PET image quality of the myocardium without the need for external devices for motion tracking.

Viabilidad miocárdica: multimodalidad – resonancia magnética cardíaca

Left ventricular dysfunction in ischaemic heart disease can occur due to stunning, hibernation, or necrosis. The non-invasive cardiac imaging techniques evaluate different objectives in the identification of potentially viable myocardium, by varying their sensitivity and specificity in order to identify them. This makes it very difficult to extrapolate myocardial viability studies between different modes. Cardiac magnetic resonance can help to evaluate by its biphasic response to dobutamine, or by gadolinium uptake in the ventricular myocardium. The most used technique is the late gadolinium enhancement, in which the transmurality of the necrosis is evaluated as a prognostic factor in the recovery of myocardial contractility.

Left Ventricular Dysfunction in Ischemic Heart Disease

Ischemic heart disease is a growing cause of heart failure owing to the increasing prevalence of diabetes, hypertension, and obesity. It is important to understand the concepts of myocardial stunning and hibernation so we as physicians can order appropriate testing on patients with ischemic heart disease, such as myocardial viability studies. Ventricular remodeling is associated with an elevated risk of death after myocardial infarction. The extent of myocardial viability determines the clinical outcome of patients after myocardial infarction. Multiple impactful clinical trials have changed the way we manage ischemic cardiomyopathy over the past few decades, and medications such as angiotensin-converting enzyme inhibitors, angiotensin II receptor blockers, beta-blockers, and aldosterone antagonists have improved outcomes in this patient population. Similarly, much has been reported on the effect of coronary artery bypass surgery on outcomes in patients with ischemic heart disease and heart failure, but further research studies are needed on the role of percutaneous coronary intervention.

Hemorrhagic Tamponade as Initial Manifestation of Systemic Lupus with Subsequent Refractory and Progressive Lupus Myocarditis Resulting in Cardiomyopathy and Mitral Regurgitation

Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease with a wide range of clinical and serological manifestations. Cardiac disease among patients with SLE is common and can involve the pericardium, myocardium, valves, conduction system, and coronary arteries. We are reporting a case of SLE in a young woman that is unique is unique in that initial symptoms consisted of pericarditis and hemorrhagic tamponade which remained progressive and resistant to aggressive immunosuppressive treatment and led to severe cardiomyopathy (ejection fraction of 25%) and severe (+4) mitral regurgitation. Her immunosuppressive treatment included hydroxychloroquine, high-dose steroids, intravenous immunoglobulins, azathioprine, and mycophenolate mofetil. Her disease progression was felt to be due to underlying uncontrolled SLE because the complement levels remained persistently low throughout the entire course and PET Myocardial Perfusion and Viability study showed stable persistent active inflammation. Eventually, she was treated with cyclophosphamide which led to improvement in ejection fraction to 55% with only mild mitral regurgitation.

MRI of the heart: basics for beginners

Cardiac magnetic resonance imaging (MRI) has emerged as a highly reproducible and accurate imaging methodology for evaluating a wide variety of congenital and acquired heart diseases, including cardiac masses, myocardial ischemia or infraction, cardiomyopathies, valvular disease, coronary artery disease, pericardial disease, and complex congenital anomalies. The high soft-tissue contrast, availability of a large FOV, multiplanar acquisition capability, and lack of ionizing radiation are particularly appealing features of cardiac MRI. Of course, there are certain technical challenges unique to cardiac MRI. Most notably is the rapid and complex motion of the heart and pulsatility of the great vessels due to normal contractility. Moreover, numerous pulse sequences have been applied to cardiac MRI. To select the optimal protocol and to interpret cardiac MRI studies, the radiologist should understand the basic pulse sequences. In addition, the radiologist interpreting cardiac MRI studies should be familiar with basic cardiac anatomy and standard imaging planes. Additionally, using delayed gadolinium enhancement cardiac MRI can depict areas of overt scar or fibrosis. As a consequence, myocardial late gadolinium enhancement (LGE) imaging is an an integral part of a myocardial viability study and has already been demonstrated to provide additional insights into conditions associated with deposition of fibrosis such as myocardial infarction, hypertrophic or dilated cardiomyopathy, as well as acute inflammatory myocarditis or other rarer cardiomyopathies. Hence LGE imaging can be used as a risk-stratification tool in ischemic as well as non-ischemic cardiac diseases.

Novedades en imagen cardiaca 2014

In this article, we review the contributions of the most important imaging techniques used in cardiology, reported in 2014. Echocardiography remains the cornerstone for diagnosing and monitoring valvular heart disease, and there has been a continuing effort to improve quantification of this condition and obtain prognostic parameters for follow-up. The study of regional myocardial function is anchored in the diagnosis of subclinical ventricular dysfunction, and 3-dimensional transesophageal echocardiography has become the perfect ally in interventional procedures for structural heart disease. Cardiac magnetic resonance imaging and cardiac computed tomography are the focus of most publications on cardiac imaging in ischemic heart disease, reflecting their consolidated use in clinical practice. Nuclear medicine excels in the study of myocardial viability after interventional treatment of acute coronary syndromes and its performance is validated in the diagnosis of ischemic heart disease.Full English text available from: www.revespcardiol.org/en

Update on Cardiac Imaging Techniques 2014

In this article, we review the contributions of the most important imaging techniques used in cardiology, reported in 2014. Echocardiography remains the cornerstone for diagnosing and monitoring valvular heart disease, and there has been a continuing effort to improve quantification of this condition and obtain prognostic parameters for follow-up. The study of regional myocardial function is anchored in the diagnosis of subclinical ventricular dysfunction, and 3-dimensional transesophageal echocardiography has become the perfect ally in interventional procedures for structural heart disease. Cardiac magnetic resonance imaging and cardiac computed tomography are the focus of most publications on cardiac imaging in ischemic heart disease, reflecting their consolidated use in clinical practice. Nuclear medicine excels in the study of myocardial viability after interventional treatment of acute coronary syndromes and its performance is validated in the diagnosis of ischemic heart disease.

Cardiac magnetic resonance imaging in clinical practice

Objective To evaluate and describe indications, mainly diagnoses and cardiac magnetic resonance imaging findings observed in clinical practice. Materials and Methods Retrospective and descriptive study of cardiac magnetic resonance performed at a private hospital and clinic in the city of Niterói, RJ, Brazil, in the period from May 2007 to April 2011. Results The sample included a total of 1000 studies performed in patients with a mean age of 53.7 ± 16.2 years and predominance for male gender (57.2%). The majority of indications were related to assessment of myocardial perfusion at rest and under pharmacological stress (507/1000; 51%), with positive results in 36.2% of them. Suspected myocarditis was the second most frequent indication (140/1000; 14%), with positive results in 63.4% of cases. These two indications were followed by study of arrhythmias (116/1000; 12%), myocardial viability (69/1000; 7%) and evaluation of cardiomyopathies (47/1000; 5%). In a subanalysis, it was possible to identify that most patients were assessed on an outpatient basis (58.42%). Conclusion Cardiac magnetic resonance has been routinely performed in clinical practice, either on an outpatient or emergency/inpatient basis, and myocardial ischemia represented the main indication, followed by investigation of myocarditis, arrhythmogenic right ventricular dysplasia and myocardial viability.

Identification of Inflamed Aortic Plaque in Conventional Fluorodeoxyglucose–Positron Emission Tomography Myocardial Viability Studies

BackgroundIt has been shown that 18F-fluorodeoxyglucose (FDG) positron emission tomography (PET) is useful in identifying inflamed plaque in major arteries. This study evaluated the feasibility of inflamed plaque detection with routinely acquired cardiac FDG-PET viability studies in patients with severe coronary artery disease and left ventricular dysfunction. MethodsClinically indicated myocardial viability scans using FDG and PET combined with computed tomography from 103 patients were retrospectively analyzed for FDG uptake in the proximal, ascending, and descending thoracic aorta. Aortic uptake was graded on the basis of peak and mean target-to-background ratio (TBR): grade 0, < 1; grade 1, 1.01-1.49; grade 2, 1.5-1.99; and grade 3, > 2. ResultsOf the 103 patients, 71 (68.9%) had a history of myocardial infarction, 88 (85.4%) were on statins, and 70 (68%) were on angiotensin-converting enzyme (ACE) inhibitors. Increased FDG uptake (mean TBR grade 1-3) was seen in 79 of 103 patients (77%), and grade 3 aortic uptake based on peak TBR was found in 12 of 103 patients (12%). ConclusionsDetection of inflamed atherosclerotic plaque in the aorta with conventional FDG viability scans is feasible. The rate of very positive uptake in this population of ischemic heart disease patients is low, possibly reflecting aggressive secondary risk factor modification including statin and ACE inhibitor use.

Long-Term Clinical Outcomes after Coronary Artery Bypass Surgery in Patients With Ischaemic Cardiomyopathy With or Without Preoperative Myocardial Viability Study

Long-Term Clinical Outcomes after Coronary Artery Bypass Surgery in Patients With Ischaemic Cardiomyopathy With or Without Preoperative Myocardial Viability Study

ALCAPA: the role of myocardial viability studies in determining prognosis

ALCAPA is optimally treated by coronary artery reimplantation early in neonatal life. Delayed diagnosis, however, is not infrequent, because symptoms often do not manifest until about 3 months of age, coinciding with the physiological nadir in pulmonary vascular resistance. With delayed diagnosis, there is potential for coronary steal and irreversible myocardial injury, which worsens outcome. To assess the utility of MRI in determining prognosis in children with surgically corrected ALCAPA. A retrospective chart review was performed in two children with ALCAPA who underwent coronary reimplantation and postoperative cardiac MRI. Both children subsequently underwent cardiac transplantation. The imaging findings and pathological findings at explant are presented. In both children, there was severe, globally depressed left ventricular systolic function and abnormal delayed enhancement in a predominantly subendocardial distribution. Pathological examination of the cardiac explants showed extensive fibrotic tissue, which correlated with areas of abnormal delayed enhancement on MRI. Severe reduction in systolic function and presence of delayed enhancement indicate extensive myocardial injury and pathologically correlate with irreversible fibrotic changes, which may help identify a subgroup of children who will not recover ventricular function and ultimately require heart transplantation.

Recent advances in cardiac PET and PET/CT myocardial perfusion imaging

Cardiovascular imaging has gained an important role in the evaluation of patients with either known or suspected coronary artery disease. The choices have expanded, imaging procedures have improved. Currently, testing procedures include echocardiography, magnetic resonance imaging, cardiac CTA, cardiac catheterization, and nuclear myocardial perfusion imaging with either single photon emission computed tomography (SPECT) or positron emission tomography (PET). Each of these imaging modalities has its strengths and weaknesses. However, SPECT myocardial perfusion imaging has emerged as a reliable and widely available tool for physicians to use in the assessment of their patient for the exclusion or presence and severity of CAD. Recently, cardiac PET has emerged as an alternative to SPECT imaging. Cardiac positron emission tomography (PET) imaging has gained considerable support and use in the field of cardiovascular imaging over the past several years. For example, delivery of the most accessible PET tracer, Rubidium-82 (RB-82) has quadrupled; the use of myocardial viability studies has increased, and the value of cardiac PET perfusion imaging is now being recognized. This recent increase in activity and interest has been spearheaded by several factors, such as availability of the camera technology, advances in cardiac PET acquisition and perfusion procedures, improved display procedures and software, as well as literature supporting the diagnostic and prognostic accuracy of PET perfusion imaging. This review will highlight cardiac PET as presented in a recent symposium with regards to differences between SPECT imaging and PET, literature supporting cardiac PET for both diagnostic accuracy and risk stratification, and features of cardiac PET/CT that differentiate it from SPECT. The review includes recent literature advances.

Effects of Left Bundle Branch Block and Right Ventricular Pacing on Assessing Myocardial Viability by Positron Emission Tomography

patients with ischemic heart disease referred for myocardial viability studies with left ventricular activation delay (left bundle branch block [LBBB] or right ventricular [RV] apical pacing) can result in altered septal uptake of both perfusion and metabolic positron emission tomography tracers.

Intense [18F]FDG tongue uptake in a case of acipimox-related angio-oedema during FDG-PET myocardial viability study

Tongue FDG uptake can occasionally be seen during FDGPET imaging, especially in patients talking after injection [1]. Orofacial angio-oedema can be triggered by various drugs [2]. Acipimox, a nicotinic acid analogue, used in FDG-PET myocardial viability studies can rarely cause angio-oedema [3]. A kidney mass suspicious for malignancy was found on MRI scan in a 74-year-old man with haematuria and coexistent advanced coronary artery disease. Myocardial perfusion assessment for pre-operative cardiac risk stratification further necessitated an FDG-PET viability study, which, because of the patient’s history, was combined with simultaneous whole-body scan. Acipimox was orally given before the administration of 460 MBq [F]FDG [3]. One hour after acipimox intake, the patient reported difficulty in swallowing. After scan completion, neck, tongue, tonsils and soft palate oedema was evident (a). Elevated total IgE (311 IU/ml; normal<100 IU/ml) was compatible with IgE-mediated angio-oedema. Whole-body scan was negative for malignancy. However, intense uptake (SUV maximum 8, average 6.2) in the tongue and mild activity along the pharynx and upper oesophagus were best shown in sagittal sections (b). Activity was located only at the posterior, swallowing-related and not at the anterior, freely moving part of the tongue. The area of activity was lacking the normal upward curved shape of the tongue, probably because of the swollen soft palate (c, arrow). In the presented case, intense FDG uptake of the tongue was shown in association with acipimox-related angiooedema. Increased muscular metabolism due to repeated swallowing efforts, triggered by the swollen soft palate, is proposed as the underlying mechanism. Eur J Nucl Med Mol Imaging (2007) 34:1320–1321 DOI 10.1007/s00259-007-0468-4

Unusual Intraventricular Flow Pattern After Left Ventricular Aneurysmorrhaphy

A 78-year-old man with coronary artery disease, prior myocardial infarction, and heart failure was referred for coronary artery bypass surgery. Left ventricular (LV) angiography showed the presence of a large apical aneurysm and, therefore, surgery included exclusion of the aneurysm using an aneurysmorphaphy patch. Myocardial viability study was not performed at this stage.