Noninvasive characterization of stunned, hibernating, remodeled and nonviable myocardium in ischemic cardiomyopathy (original) (raw)
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2010
We evaluated a novel protocol of dual-isotope, gated single-photon emission computed tomographic (SPECT) imaging combined with low and high dose dobutamine as a single test for the characterization of various types of altered myocardial dysfunction. BACKGROUND Myocardial perfusion tomography and echocardiography have been used separately for the assessment of myocardial viability. However, it is possible to assess perfusion, function and contractile reserve using gated SPECT imaging.
Quantitative analysis of hibernating myocardium by dobutamine tissue Doppler echocardiography
The American Journal of Cardiology, 2001
D obutamine stress echocardiography is a useful modality to detect hibernating myocardium in patients with chronic coronary artery disease. 1,2 A quantitative assessment of myocardial wall velocities can be obtained by tissue Doppler echocardiography (TDE) analysis, 3-5 a method that can quantify regional myocardial velocities objectively and detect subtle alteration of contractility during stress echo. 6 -8 In patients with coronary artery disease, TDE has been applied to the study of old or recent infarctions apparently related to a 1-vessel stenosis in patients free from left ventricular dysfunction. 5,9 A decrease in myocardial velocity gradients has also been reported during dobutamine challenge on 1-vessel coronary lesions without myocardial infarction. 6 Our study addresses a population of patients presenting with left ventricular dysfunction with ejection fraction Ͻ50% related to chronic and severe 3-vessel disease. To image more segments in these patients with multivessel disease, we used an apical TDE approach at rest and under dobutamine. The study was designed to test if the obtained quantitative information could enable detection of viable or nonviable segments in this specific population.
European Journal of Cardio-Thoracic Surgery, 2001
Objective: It has been demonstrated that positron emission tomography (PET) predicts the functional recovery of viable but ischemically compromised myocardium. Reversible contractile dysfunction after revascularization has been reported for`hibernating myocardium' and stunned myocardium, however, there are little data concerning the time-course and the extent of improvement of the two different pathophysiological conditions. Methods: Twenty-nine patients with advanced coronary artery disease and severely reduced left ventricular function (EF 18±35%) who were referred for isolated coronary artery bypass grafting underwent preoperative PET viability assessment and were functionally assessed by two-dimensional echocardiography preoperatively at 11 days, 14 weeks, and more than 12 months after surgical revascularization. Intraoperative biopsies were taken from dysfunctional areas de®ned by PET as segments of normal perfusion and normal metabolism (stunned myocardium) and from areas with a`mismatch' between perfusion and metabolism (hibernating myocardium). The degree of morphological alterations was evaluated by electron microscopy. Results: In 70% of the 240 dysfunctional segments,`stunned myocardium' was present whereas`hibernating myocardium' could be detected in only 24% P , 0:01: Hibernating myocardium was associated with more severe preoperative wall motion abnormalities and incomplete postoperative recovery. After 1 year, 31% of`stunned' segments vs. only 18% of`hibernating' segments showed complete functional restoration P , 0:05: This incomplete improvement was associated with more severe morphological alterations including depletion of sarcomeres, accumulation of glycogen, loss of sarcoplasmatic reticulum, and cellular sequestration. Conclusions: These data indicate that in patients with severe ischemic left ventricular dysfunctioǹ stunned myocardium' is more prevalent than`hibernation'. Functional normalization is more frequent in`stunned' segments, whereas areas of`hibernation' showed more severe tissue injury and protracted recovery. Different degrees of myocardial injury coexist in most patients, which determines the time-course and the extent of improvement after revascularization. q
The quarterly journal of nuclear medicine and molecular imaging : official publication of the Italian Association of Nuclear Medicine (AIMN) [and] the International Association of Radiopharmacology (IAR), [and] Section of the Society of Radiopharmaceutical Chemistry and Biology, 2004
In patients with ischemic cardiomyopathy, the differentiation of dysfunctional myocardium in scarred versus hibernating is oversimplified. We evaluated a more complex classification using an imaging technique currently employed for viability detection, having as reference the postrevascularization outcome of dysfunctional segments. In 35 patients, we performed gated single-photon emission computed tomography (SPECT) (resting and nitrate-enhanced study, the latter with baseline and dobutamine acquisition) before revascularization. The outcome after revascularization was assessed by repeating resting gated SPECT. Dysfunctional segments without functional recovery in postrevascularization gated SPECT were defined scar (either nontransmural or transmural according to tracer activity); those with recovery were divided in stunned (unchanged uptake) or hibernating (improved postrevascularization activity). This reference classification was compared with the categorization based on prerevas...
Imaging techniques for the assessment of myocardial hibernation
European heart …, 2004
This report of an ESC Study Group reviews current knowledge on myocardial hibernation and relevant imaging techniques, and provides an algorithm for investigation and management when a patient presents with ischaemic left ventricular dysfunction. It covers the definitions of myocardial viability, stunning and hibernation, it reviews the morphological findings in hibernation and it describes relevant clinical settings. The imaging and other techniques that are reviewed are electrocardiography, positron-emitting and single photon-emitting scintigraphic imaging, echocardiography, radionuclide angiocardiography, magnetic resonance imaging, X-ray transmission tomography, invasive X-ray angiocardiography and electromechanical mapping. The evidence for the techniques to predict improvement of regional and global function after revascularisation is summarised and patient symptoms and clinical outcome are also considered. Each technique is classified in its ability to assess myocardial viability, function and perfusion and also for their roles in the assessment of the patient with ischaemic left ventricular dysfunction who is asymptomatic or who has angina or heart failure. A simplified clinical algorithm describes the initial assessment of left ventricular function, then viability and then perfusion reserve allowing regions of myocardium to be characterised as transmural scar, intramural scar, hibernation or ischaemia.
Texas Heart Institute journal / from the Texas Heart Institute of St. Luke's Episcopal Hospital, Texas Children's Hospital, 1995
As investigators have discovered that cardiac regions displaying resting wall motion abnormalities are not the necessary equivalent of myocardial scar (and therefore of irreversible injury) but are potentially viable regions rendered dysfunctional by stunning or hibernation, a new field of medicine has developed to identify viable myocardium that can improve in function after revascularization. Moreover, improvements in myocardial preservation and perfusion during coronary artery bypass grafting and percutaneous transluminal coronary angioplasty have enabled patients with poor resting ejection fractions to undergo safer revascularization. In this review, we describe briefly the diagnostic techniques most commonly used in identifying dysfunctional but viable myocardium. We give specific attention to the assets and limitations of these techniques and special emphasis to 2 promising new techniques: dobutamine echocardiography and myocardial contrast echocardiography.
Circulation, 1998
Background —Both radionuclide perfusion tracers and contractile response to dobutamine have been used to identify hibernating myocardium. The aim was to compare 201 Tl (thallium) single photon emission CT (SPECT), 99m Tc-tetrofosmin (tetrofosmin) SPECT, and dobutamine cine MRI for identifying regions of reversible myocardial dysfunction. Methods and Results —Thirty patients with 3-vessel coronary artery disease and impaired left ventricular function (mean LVEF, 24.0%; SD, 8.3%) scheduled for coronary bypass grafting were recruited. All underwent rest/dobutamine stress (5 to 10 μg · kg −1 · min −1 ) cine MRI, stress/rest tetrofosmin SPECT, and stress/redistribution and separate-day rest/redistribution thallium SPECT before surgery. Stress/redistribution thallium SPECT and resting MRI were repeated after surgery. In a 9-segment model, SPECT images were scored visually for tracer uptake, which was also measured from a polar plot of myocardial counts. MRI was scored visually for endocar...
The assessment of myocardial viability: a review of current diagnostic imaging approaches
Journal of …, 2002
The management of patients with coronary artery disease, both in the postinfarction setting, and in patients with chronic advanced left ventricular (LV) dysfunction, is complicated by the presence of both reversibly damaged and infarcted myocardium. Although acute revascularization with thrombolytic therapy and percutaneous angioplasty have served to reduce the overall mortality from myocardial infarction, the ability to predict whether or not dysfunctional myocardium will recover following revascularization presents the clinician with a serious challenge. The success of revascularization, both on improvement of LV function, and short and long-term prognosis, depends on both the existence and extent of viable but dysfunctional myocardium present, as there is little to be gained from revascularizing a territory consisting exclusively of scar. There is a clear demand for procedures that can identify reversible asynergy prospectively and thus deliver the information that is needed for clinical decision-making. The objective of this review is to summarize the diagnostic tools that are currently available for the identification of reversible injury (i.e., stunned or hibernating myocardium). The relative merits of echocardiography, nuclear medicine imaging, and magnetic 381
Journal of nuclear medicine : official publication, Society of Nuclear Medicine, 2001
The identification of severely dysfunctional but viable myocardium is of particular importance for the selection of patients with depressed left ventricular function who will benefit from coronary revascularization. Assessment of inotropic reserve with dobutamine has recently been used for this purpose. This study compared the accuracy of low-dose dobutamine stress gated myocardial SPECT (DS SPECT) with the accuracy of dobutamine stress echocardiography (DSE) and resting perfusion SPECT for the identification of viable myocardium in patients with previous myocardial infarction. Resting and low-dose dobutamine (7.5 microg/kg/min) gated (99m)Tc-tetrofosmin SPECT and echocardiography and resting (18)F-FDG PET were prospectively studied in 23 patients with previous myocardial infarction and severely depressed regional function. Twenty-one of them were successfully studied with each technique. The left ventricular wall was divided into 14 segments to assess wall motion using a 5-point sc...
Heart (British Cardiac Society), 1999
Since the pioneering works of Tennant and Wiggers, 1 it has been known that total ischaemia leads to a prompt cessation of contraction and eventually results in the appearance of cell damage and irreversible myocardial necrosis. Accordingly, in the minds of many cardiologists, the discovery of an abnormal regional contraction in a patient with coronary artery disease had long been equated with the presence of irreversible myocardial necrosis. However, with the advent of recanalisation treatment, evidence progressively accumulated that prolonged regional "ischaemic" dysfunction did not always arise from irreversible tissue damage and, to some extent, could be reversed by the restoration of blood flow. 2-5 These observations have led to the speculation that chronically jeopardised myocardium, which is often referred to as "hibernating", 2-7 could spontaneously downgrade its contractile function and minimise its energy requirements to prevent the appearance of irreversible tissue damage. 2 4 5 During the past decade, the pathophysiology of the hibernating myocardium has received considerable attention and has fostered the development of several new modalities aimed at predicting the return of left ventricular function after revascularisation. Among these modalities, dobutamine stress echocardiography 8-24 has recently emerged as a safe, non-invasive, and accurate way of identifying viable myocardium. It is the purpose of this paper to review some of the more recent advances in the understanding of the pathophysiology of chronic myocardial hibernation and the use of dobutamine echocardiography to identify viable myocardium. Emphasis will be placed on regional perfusion-contraction matching in both the experimental and the clinical setting, on the peculiar morphological changes that have been shown to occur in the hibernating myocardium, on the determinants of mechanical reversibility after restoration of adequate coronary patency, and on the presence of recruitable inotropic reserve.