The Current Role of Viability Imaging to Guide Revascularization and Therapy Decisions in Patients With Heart Failure and Reduced Left Ventricular Function

This review describes the current evidence and controversies for viability imaging to direct revascularization decisions and the impact on patient outcomes. Balancing procedural risks and possible benefit from revascularization is a key question in patients with heart failure of ischemic origin (IHF). Different stages of ischemia induce adaptive changes in myocardial metabolism and function. Viable but dysfunctional myocardium has the potential to recover after restoring blood flow. Modern imaging techniques demonstrate different aspects of viable myocardium; perfusion (single-photon emission computed tomography [SPECT], positron emission tomography [PET], cardiovascular magnetic resonance [CMR]), cell metabolism (PET), cell membrane integrity and mitochondrial function (201Tl and 99mTc-based SPECT), contractile reserve (stress echocardiography, CMR) and scar (CMR). Observational studies suggest that patients with IHF and significant viable myocardium may benefit from revascularization compared with medical treatment alone but that in patients without significant viability, revascularization appears to offer no survival benefit or could even worsen the outcome. This was not supported by 2 randomized trials (Surgical Treatment for Ischemic Heart Failure [STICH] and PET and Recovery Following Revascularization [PARR] -2) although post-hoc analyses suggest that benefit can be achieved if decisions had been strictly based on viability imaging recommendations. Based on current evidence, viability testing should not be the routine for all patients with IHF considered for revascularization but rather integrated with clinical data to guide decisions on revascularization of high-risk patients with comorbidities.     

Myocardial viability–State of the art: Is it still relevant and how to best assess it with imaging?

Despite major advances, ischemic cardiomyopathy (ICM) remains a significant cause of death and disability worldwide, with coronary artery disease (CAD) the leading cause of left ventricular (LV) systolic dysfunction. Coronary revascularization may improve LV function, heart failure symptoms and cardiovascular outcomes in high-risk patients with myocardial viability. Multiple imaging modalities have been utilized to detect viable myocardium and predict functional recovery following revascularization. Dobutamine stress echocardiography (DSE), nuclear imaging and cardiac MRI (CMR) are frequently used to assess viability. This review will summarize the extant literature on this topic, describe the role and methods for viability imaging in modern clinical practice, provide a patient-centered perspective regarding the controversies surrounding the current utility of viability imaging, as well as discuss future directions.     

QT dispersion is determined by the relative extent of normal, hibernating, and scarred myocardium in patients with chronic ischemic cardiomyopathy. A dobutamine stress echocardiography study before and after surgical revascularization

INTRODUCTION: The aim of the present study was to evaluate a possible association between QT dispersion (QTd) and the amount of viable and scarred myocardial tissue after revascularization in patients with coronary artery disease and impaired left ventricular (LV) function. METHODS: Twenty-two patients with ischemic LV dysfunction underwent dobutamine stress echocardiography (DSE) before and 6 months after surgical revascularization. Mean corrected QT-interval value and QTd were calculated at baseline and follow-up. Segments consisting of transmural scar were determined as the segments that remained akinetic in all stages of DSE despite reperfusion. Patients were divided into 2 groups according to the number of definitive segments consisting of transmural scar (minor scar group, < or =2 scarred segments; major scar group, >2 scarred segments). RESULTS: QTd was significantly lower in the minor compared with the major scar group at baseline and follow-up (mean [SD], 61 [22] vs 98 [33] milliseconds, P = .008, and 45 [18] vs 68 [21] milliseconds, P = .01, respectively). Segments consisting of transmural scar positively correlated to QTd at baseline (r = 0.53, P = .01) and follow-up (r = 0.62, P = .002). CONCLUSIONS: QTd is positively correlated with the extent of scarred myocardial tissue assessed by DSE. Surgical revascularization results in reduction of QTd in all patients with hibernating myocardium and LV dysfunction.     

Implantation of a Novel Allogeneic Mesenchymal Precursor Cell Type in Patients with Ischemic Cardiomyopathy Undergoing Coronary Artery Bypass Grafting: an Open Label Phase IIa Trial

Heart failure is a life-limiting condition affecting over 40 million patients worldwide. Ischemic cardiomyopathy (ICM) is the most common cause. This study investigates in situ cardiac regeneration utilizing precision delivery of a novel mesenchymal precursor cell type (iMP) during coronary artery bypass surgery (CABG) in patients with ischemic cardiomyopathy (LVEF?<?40 %). The phase IIa safety study was designed to enroll 11 patients. Preoperative scintigraphy imaging (SPECT) was used to identify hibernating myocardium not suitable for conventional myocardial revascularization for iMP implantation. iMP cells were implanted intramyocardially in predefined viable peri-infarct areas that showed poor perfusion, which could not be grafted due to poor target vessel quality. Postoperatively, SPECT was then used to identify changes in scar area. Intramyocardial implantation of iMP cells with CABG was safe with preliminary evidence of efficacy of improved myocardial contractility and perfusion of nonrevascularized territories resulting in a significant reduction in left ventricular scar area at 12 months after treatment. Clinical improvement was associated with a significant improvement in quality of life at 6 months posttreatment in all patients. The results suggest the potential for in situ myocardial regeneration in ischemic heart failure by delivery of iMP cells.     

Subendocardial and Transmural Myocardial Ischemia: Clinical Characteristics,Prevalence, and Outcomes With and Without Revascularization

BackgroundSubendocardial ischemia is commonly diagnosed but not quantified by imaging.ObjectivesThis study sought to define size and severity of subendocardial and transmural stress perfusion deficits, clinical associations, and outcomes.MethodsRegional rest-stress perfusion in mL/min/g, coronary flow reserve, coronary flow capacity (CFC), relative stress flow, subendocardial stress-to-rest ratio and stress subendocardial-to-subepicardial ratio as percentage of left ventricle were measured by positron emission tomography (PET) with rubidium Rb 82 and dipyridamole stress in serial 6,331 diagnostic PETs with prospective 10-year follow-up for major adverse cardiac events with and without revascularization.ResultsOf 6,331 diagnostic PETs, 1,316 (20.7%) had severely reduced CFC with 41.4% having angina or ST-segment depression (STΔ) >1 mm during hyperemic stress, increasing with size. For 5,015 PETs with no severe CFC abnormality, 402 (8%) had angina or STΔ during stress, and 82% had abnormal subendocardial perfusion with 8.7% having angina or STΔ >1 mm during dipyridamole stress. Of 947 cases with stress-induced angina or STΔ >1 mm, 945 (99.8%) had reduced transmural or subendocardial perfusion reflecting sufficient microvascular function to increase coronary blood flow and reduce intracoronary pressure, causing reduced subendocardial perfusion; only 2 (0.2%) had normal subendocardial perfusion, suggesting microvascular disease as the cause of the angina. Over 10-year follow-up (mean 5 years), severely reduced CFC associated with major adverse cardiac events of 44.4% compared to 8.8% for no severe CFC (unadjusted P < 0.00001) and mortality of 15.2% without and 6.9% with revascularization (P < 0.00002) confirmed by multivariable Cox regression modeling. For no severe CFC, mortality was 3% with and without revascularization (P = 0.90).ConclusionsReduced subendocardial perfusion on dipyridamole PET without regional stress perfusion defects is common without angina, has low risk of major adverse cardiac events, reflecting asymptomatic nonobstructive diffuse coronary artery disease, or angina without stenosis. Severely reduced CFC causes angina in fewer than one-half of cases but incurs high mortality risk that is significantly reduced after revascularization.     

Detection of Viability of Dysfunctional Myocardium in Coronary Heart Disease. II. Echocardiography

The detection of viable myocardium in patients with severe left ventricular (LV) dysfunction is important because these patients benefit most from revascularization. Three echocardiographic techniques can be used for the noninvasive assessment of functional correlates of viable myocardium. Two-dimensional echocardiography (2DE) is well suited for quantifying resting LV regional and global systolic function and dysfunction before and after revascularization, in addition to providing data on chamber size, shape, and wall thicknesses. The presence of hypokinesis on a resting 2DE indicates that viable myocardium is definitely present, but presence of dykinesis does not exclude viability. Dobutamine stress echocardiography (DSE) before revascularization unmasks viability by demonstrating augmentation of systolic function. Several clinical studies have shown that improvement of regional function during DSE indicates contractile reserve and predicts improvement of function after revascularization. A biphasic response on DSE appears to predict residual coronary artery stenosis and is a reliable marker of viability. DSE also appears to be useful after revascularization for unmasking contractile reserve. Myocardial contrast echocardiography (MCE) detects viability by defining microvascular perfusion, the extent of myocardium at risk, and coronary flow reserve. The clinical utility of MCE is undergoing evaluation. The combination of DSE and MCE might provide an improved estimate of the extent of viable myocardium based on assessment of function and perfusion. Meanwhile, echocardiographic and nuclear techniques can be used to complement each other in the assessment of myocardial viability.     

Impairment of Subendocardial Perfusion Reserve and Oxidative Metabolism in Nonischemic Dilated Cardiomyopathy

BackgroundCardiac magnetic resonance (CMR) and [¹¹C]acetate positron emission tomography (PET) were used to assess the hypothesis that patients with nonischemic dilated cardiomyopathy (NIDCM) have decreased subendocardial perfusion reserve and impaired oxidative metabolism, consistent with the concept of “energy starvation” in heart failure (HF).Methods and ResultsCMR myocardial perfusion was evaluated in 13 NIDCM patients and 15 control subjects with coronary risk factors and normal myocardial perfusion. The NIDCM patients underwent [¹¹C]acetate PET. The myocardial perfusion index (MPI) was calculated as the normalized rate of myocardial signal augmentation following gadolinium contrast injection. Hyperemic transmural, subendocardial, and subepicardial MPI were reduced in NIDCM compared with control subjects [0.13 vs 0.18 (P < .001), 0.13 vs 0.17 (P < .001), and 0.13 vs 0.17 (P = .008), respectively]. The subendocardial perfusion reserve was 1.59 ± 0.21 vs 1.86 ± 0.32 for the subepicardium (P = .002), demonstrating reduced perfusion reserve. The myocardial oxidative metabolic rate (k_mono) per unit demand (rate-pressure product) was reduced in proportion to perfusion reserve (P = .02)ConclusionsImpaired subendocardial perfusion reserve in NIDCM confirmed results previously attained only in animal models. Impaired perfusion and impaired oxidative metabolism are consistent with subendocardial energy starvation in HF.     

No difference in cardiac event-free survival between positron emission tomography-guided and single-photon emission computed tomography-guided patient management: a prospective, randomized comparison of patients with suspicion of jeopardized myocardium

OBJECTIVES: We sought to prospectively compare nitrogen-13 (13N)-ammonia/18fluorodeoxyglucose (18FDG) positron emission tomography (PET)-guided management with stress/rest technetium-99m (99mTc)-sestamibi single-photon emission computed tomography (SPECT)-guided management. BACKGROUND: Patients with evidence of jeopardized (i.e., ischemic or viable) myocardium may benefit from revascularization, whereas patients without it should be treated with drugs. Both PET and SPECT imaging have been proven to delineate jeopardized myocardium. When patient management is based on identification of jeopardized myocardium, it is unknown which technique is most accurate for long-term prognosis. METHODS: In a clinical setting, 103 patients considered for revascularization with left ventricular wall motion abnormalities and suspicion of jeopardized myocardium underwent both PET and SPECT imaging. The imaging results were used in a randomized fashion to determine management (percutaneous transluminal coronary angioplasty [PTCA], coronary artery bypass graft surgery [CABG] or drug treatment). Follow-up for cardiac events (cardiac death, myocardial infarction and revascularization) was recorded for 28 +/- 1 months. The study was designed to have a power of 80% to detect a 20% difference in the event rate between PET- and SPECT-based management. RESULTS: Management decisions in 49 patients randomized to PET (12 who had PTCA, 14 CABG and 23 drug therapy) were comparable with 54 patients randomized to SPECT (15 who had PTCA, 13 CABG and 26 drug therapy). In terms of cardiac event-free survival, no differences between PET and SPECT were observed (11 vs. 13 cardiac events for PET and SPECT, respectively; p = NS by the Kaplan-Meier statistic). CONCLUSIONS : No difference in patient management or cardiac event-free survival was demonstrated between management based on 13N-ammonia/18FDG PET and that based on stress/rest 99mTc-sestamibi SPECT imaging. Both techniques may be used for management of patients considered for revascularization with suspicion of jeopardized myocardium.     

Metabolic imaging using F18-fluorodeoxyglucose to assess myocardial viability

Over the past 10 years, F18-fluorodeoxyglucose (FDG) imaging with positron emission tomography (PET) has emerged as an important technique in the delineation of myocardial viability. Using this technique it has become possible to predict recovery of ventricular function after revascularization in patients with chronic coronary artery disease. Data from long-term (although retrospective) follow-up studies have demonstrated that patients with viable myocardium on FDG PET who do not undergo revascularization are prone to cardiac events, including cardiac death and non-fatal infarction. The same studies have pointed out that patients with viable tissue on FDG PET, who do undergo revascularization, improve substantially in symptoms related to congestive heart failure. To allow FDG imaging in centers without PET equipment, recent studies have evaluated the use of FDG imaging with single photon emission computed tomography (SPECT) and 511 keV collimators. Preliminary data using this alternative approach are promising, but need further confirmation. In this review the experience with FDG imaging (using either PET or SPECT) in the assessment of tissue viability in patients with coronary artery disease will be discussed.     

Prediction of nonviable myocardium by ECG Q-Wave parameters: A 3.0 T cardiovascular magnetic resonance study

IntroductionThe presence of a Q-wave on a 12-lead electrocardiogram (ECG) has been considered a marker of a large myocardial infarction (MI). However, the correlation between the presence of Q-waves and nonviable myocardium is still controversial. The aims of this study were to 1) test QWA, a novel ECG approach, to predict transmural extent and scar volume using a 3.0 Tesla scanner, and 2) assess the accuracy of QWA and transmural extent.MethodsConsecutive patients with a history of coronary artery disease who came for myocardial viability assessment by CMR were retrospectively enrolled. Q-wave measurements parameters including duration and maximal amplitude were performed from each surface lead. A 3.0 Tesla CMR was performed to assess LGE and viability.ResultsTotal of 248 patients were enrolled in the study (with presence (n = 76) and absence of pathologic Q-wave (n = 172)). Overall prevalence of pathologic Q-waves was 27.2% (for LAD infarction patients), 20.0 % (for LCX infarction patients), and 16.8% (for RCA infarction patients). Q-wave area demonstrated high performance for predicting the presence of a nonviable segment in LAD territory (AUC 0.85, 0.77–0.92) and a lower, but still significant performance in LCX (0.63, 0.51–0.74) and RCA territory (0.66, 0.55–0.77). Q-wave area greater than 6 ms mV demonstrated high performance in predicting the presence of myocardium scar larger than 10% (AUC 0.82, 0.76–0.89).ConclusionQ-wave area, a novel Q-wave parameter, can predict non-viable myocardial territories and the presence of a significant myocardial scar extension.     

The dilemma of ischemic heart failure; how FDG-PET can guide therapy and improve outcomes? Case report

Patients with ischemic LV dysfunction are at increasing risk of adverse cardiac events including sudden cardiac death. Proper revascularization of viable ischemic myocardium (compared to medical treatment alone) is associated with improvement of LV systolic function, less cardiac morbidities & mortalities and better functional capacity and well-being. Many diagnostic tools are used in clinical practice for assessment of myocardial viability. Dobutamine stress Echocardiography (DSE) is the most widely used technique, while delayed enhancement cardiac magnetic resonance (DE-CMR) and Flourine-18-fluorodeoxy-glucose positron emission tomography (18F-FDG PET) are considered the standard of care for assessment of myocardial viability. Our case report illustrates how FDG PET myocardial viability assessment can guide therapy and improve outcomes in a difficult clinical and angiographic situation.     

Assessment of myocardial viability in ischemic heart disease by cardiac magnetic resonance imaging

Assessment of myocardial viability aims at differentiating between viable and non-viable myocardium. The proof of dysfunctional but viable myocardium is crucial to predict outcome of revascularization after acute (AMI) and chronic myocardial infarction (CMI). Cardiac magnetic resonance imaging (CMRI) offers different options to detect viable myocardium: Measurements of end-diastolic wall thickness by cine-CMRI can be used to depict chronically scarred myocardium, but fails to detect acute myocardial necrosis. Low-dose dobutamine stimulation (LDDS) cine-CMRI analyses the contractile reserve of dysfunctional but viable myocardium under pharmacologic stimulus to identify viable myocardium in AMI and CMI with high specificity. Sensitivity of LDDS cine-CMRI is superior to LDDS echocardiography but reduced in patients with severely impaired left ventricular (LV) function. The delayed-enhancement (DE) technique directly visualises non-viable myocardium due to an altered contrast-media distribution in necrotic and fibrotic tissue. DE-CMRI identifies non-viable myocardium with high spatial resolution independently from LV function. The transmural extent of contrast enhancement in DE-CMRI is used to predict functional recovery after revascularization in AMI and CMI. Furthermore, the amount and pattern of contrast enhancement in DE-CMRI provide important prognostic information in both entities. Recent studies demonstrated the superiority of DE-CMRI compared to single photon emission tomography (SPECT) and positron emission tomography (PET) to assess myocardial viability. Therefore, DE-CMRI is currently recognised as the standard of reference for assessment of myocardial viability. The technical background, clinical application and accuracy of the different CMRI techniques to assess myocardial viability in AMI and CMI are discussed in this work.     

The use of dobutamine stress echocardiography for the determination of myocardial viability

Determining the presence of viable myocardium has prognostic and therapeutic implications in the treatment of ischemic heart disease. Dobutamine stress echocardiography (DSE) is one possible technique to help identify both hibernating and stunned but viable myocardium. Low-dose dobutamine infusion has an increased inotropic effect, while higher doses cause both inotropic and chronotropic effects. Thus, at lower doses cardiac augmentation occurs, and at higher doses regions of ischemia may be produced in the presence of significant coronary artery disease. This is manifested echocardiographically as changes in segmental wall motion. in theory, therefore, areas of viable myocardium should show improved wall motion at low doses, and areas of irreversible myocardial damage will remain akinetic. Five studies have investigated DSE for determining viability in the setting of acute myocardial infarction, thus looking for stunned but viable myocardium. DSE was shown to compare favorably with positron emission tomography and was highly sensitive and specific for predicting functional myocardial recovery. Five additional studies examined DSE for determining the presence of hibernating myocardium. The sensitivity and specificity of DSE were found to range from 71 to 92% and from 73 to 93%, respectively. The benefits of DSE include lower cost, convenience to both patient and physician, additional ancillary information, and determination of the possible need for urgent revascularization. Limitations of DSE include occasional technical difficulty in obtaining and interpreting studies and the need for larger volumes of viable myocardium to detect changes predictive of functional recovery. Larger trials are currently underway to confirm DSE as a reliable technique for determining myocardial viability.     

Are technetium-99m-labeled myocardial perfusion agents adequate for detection of myocardial viability?

The noninvasive assessment of myocardial viability in patients with coronary artery disease and depressed left ventricular function has proven clinically useful for identifying those patients with ischemic cardiomyopathy who benefit most from coronary revascularization. Thallium-201 (²⁰¹T1) imaging at rest has been the radionuclide imaging technique most often utilized for distinguishing viable myocardium from scar. However, new technetium-99m (^99mTc) perfusion agents such as ^99mTc-sestamibi and ^99mTc-tetrofosmin have emerged as alternatives to ²⁰¹T1 for imaging of regional myocardial perfusion. Whether these new agents, which have better physical properties for imaging with a gamma camera than ²⁰¹T1, are valid for use in assessing myocardial viability is still uncertain. Recent clinical studies have demonstrated that these agents, when imaged using quantitative SPECT, can identify patients with myocardial hibernation who exhibit improved regional systolic function following revascularization. Experimental laboratory studies have shown that the uptake of ^99mTc-sestamibi and ^99mTc-tetrofosmin in ischemic myocardium is only slightly lower than the uptake of ²⁰¹T1. These ^99mTc-labeled agents remain bound intracellularly in mitochondria of viable myocytes under conditions of myocardial stunning and short-term hibernation, producing severe myocardial asynergy. With respect to determination of viability, the inferior wall region is at times problematic since attenuation of ^99mTc-sestamibi and ^99mTc-tetrofosmin is greatest in this area. Demonstration of preserved systolic thickening on ECG-gated SPECT images is indicative of viability in the instance of decreased regional ^99mTc counts due to attenuation and not scar. Administration of nitrates prior to tracer injection improves the sensitivity for identifying viable myocardial segments using rest imaging with ^99mTc-sestamibi or ^99mTc-tetrofosmin. Thus, it appears that the new ^99mTc perfusion imaging agents can be successfully employed for the determination of myocardial viability in the setting of severe regional dysfunction and chronic coronary artery disease. The greater the myocardial uptake of these agents in the resting state, the greater the probability of improved systolic function after coronary revascularization.     

Comparison between myocardial contrast echocardiography and single-photon emission computed tomography for predicting transmurality of acute myocardial infarction

Contrast-enhanced cardiovascular magnetic resonance imaging (CMR) has been shown to accurately assess transmural extent of infarction, which is an excellent predictor of long-term improvement in contractile function. We assessed the relative accuracy of myocardial contrast echocardiography (MCE) and single-photon emission computed tomography (SPECT) to predict transmural extent of infarction after acute myocardial infarction. MCE, SPECT, and CMR were performed in 40 patients with acute myocardial infarction 7 to 10 days after thrombolysis. CMR was used to divide the transmural extent of infarction into 5 groups: 0%, 1% to 25%, 26% to 50%, 51% to 75%, and 76% to 100% in dysfunctional segments. MCE and SPECT were compared with assessment grades of transmural extent of infarction. There was a significant relation (p<0.0001) between decreasing contrast intensity as assessed qualitatively by MCE and increasing transmural extent of infarction on CMR as was the case for SPECT. The accuracy of MCE (77%) to predict>50% transmural extent of infarction (nonviable myocardium) was significantly (p=0.02) superior to that of SPECT (70%). Absence of uptake on MCE and SPECT virtually ruled out 25% transmural extent of infarction (84% vs 76%, p=0.03). MCE and SPECT correlate well with the transmural extent of infarction. However, MCE is significantly more accurate in predicting >50% of the transmural extent of infarction and more sensitive in identifying 相似文献   

Collateral blood supply to the myocardium at risk in human myocardial infarction: a quantitative postmortem assessment

The relation between the type and size of myocardial infarcts and collateral development was studied in postmortem human hearts with a new approach that allows quantification of vascular beds. The coronary arteries were perfused with radioactive microspheres and were visualized by injecting a barium-gelatin mixture. The collateral supply was assessed in 6 reference hearts without infarction, 4 hearts with a transmural infarct and 12 hearts with a total of 16 subendocardial infarcts. The distribution pattern of microspheres in hearts in the reference group did not differ significantly from that in hearts with a transmural infarct but was significantly different (p less than 0.01) from that in hearts with a subendocardial infarct, which had a much greater number of microspheres in the collateral-dependent area. Moreover, the lateral zone of myocardium at risk--defined as the area containing viable myocardium but within the distribution zone of the occluded artery--was small in hearts with a transmural infarct (less than or equal to 2 mm), but showed a much wider range in hearts with a subendocardial infarct. This study strongly suggests that collateral vessels play an important role during the development of myocardial infarction, both in determining infarct type (transmural versus subendocardial) and in preserving the viability of the lateral zone of the myocardium at risk.     

Prognostic Impact of Ischemic Mitral Regurgitation Severity and Myocardial Infarct Quantification by Cardiovascular Magnetic Resonance

ObjectivesThis study sought to evaluate the role of cardiac magnetic resonance (CMR) for the quantification of ischemic mitral regurgitation (IMR) and myocardial infarct size (MIS) in patients with ischemic cardiomyopathy (ICM). This study also sought to explore the interaction between IMR severity and MIS and its association with outcomes in patients with ICM.BackgroundIMR occurs secondary to a disease of the left ventricle and is associated with poor outcomes. The role of CMR for the evaluation and risk stratification of patients with ICM and IMR remains uncertain.MethodsConsecutive patients with ICM who underwent baseline CMR were included. MIS was quantified on late gadolinium enhancement imaging as the proportion of left ventricular mass. IMR was quantified with CMR by calculating the mitral regurgitant fraction (MRFraction). Cox proportional hazards models were built to assess the association of IMR and MIS quantification with the combined endpoint of all-cause death or heart transplant.ResultsWe evaluated 578 patients (mean age: 62 ± 11 years, 76% males). The mean left ventricular ejection fraction was 25 ± 11%, with an MIS of 24 ± 16% and MRFraction of 18 ± 17%. Over a median follow-up time of 4.9 years, 198 (34%) patients experienced death or cardiac transplant. On multivariable analysis, after comprehensive medical risk score, subsequent revascularization, implantable cardioverter-defibrillator insertion, and surgical mitral valve intervention were controlled for, the interaction of IMR severity and MIS emerged as a powerful predictor of adverse outcomes (p = 0.008). For patients with significant IMR (MRFraction: ≥35%), the hazard ratio comparing moderate MIS (15% to 29%) versus small MIS (<15%) was 1.51 (0.57 to 3.98), and the hazard ratio comparing large MIS (≥30%) versus small MIS was 5.41 (2.34 to 12.7).ConclusionsRisk associated with IMR is more comprehensively described as an interaction between IMR severity and MIS. Further studies in patients IMR using comprehensive CMR evaluation are needed to verify whether this approach can improve patient selection and procedural outcomes to address IMR.     

Comparison of pressure measurement,dobutamine contrast stress echocardiography and SPECT for the evaluation of intermediate coronary stenoses. The COMPRESS trial

BACKGROUND: DSE and SPECT are two well-established methods to non-invasively investigate the functional significance of coronary artery stenoses in patients with coronary artery disease. The measurement of Fractional Flow Reserve has emerged a new invasive reference standard for lesion specific quantification of coronary artery stenoses. The objective of our prospective study was to compare sensitivity and specificity of Dobutamine Stress Echocardiography (DSE) and Single Photon Emission Computer tomography (SPECT) with the pressure derived Frational Flow Reserve (FFR) for the identification of hemodynamic relevant cororonary lesions in patients with predominantely coronary multivessel disease and angiographically intermediate stenoses. METHODS: Inclusion criteria were a coronary lesion of 50-75% diameter stenosis by visual assessment in patients with known or suspected CAD. SPECT, DSE and FFR testing was performed within one week of coronary angiography RESULTS: The study comprised 48 consecutive symptomatic patients. In 41 cases, a coronary multivessel disease was present. Mean FFR was 0.80?±?0.13 (0.41-1.0). Overall sensitivity of DSE and SPECT was 67% and 69% whereas specificity reached 77% and 87%. However, sensitivity was significantly reduced if the target lesion was located distally. DSE showed poor results if the lesions were located in the circumflex artery or if a history of prior myocardial infarctions was present. CONCLUSION: DSE and SPECT are both useful methods for the non-invasive assessment of coronary artery disease. DSE showed reasonable combination of sensitivity and specificity even in patients with multivessel disease. Although use of noninvasive stress tests is only limited in patients with prior myocardial infarctions and invasive stress testing should be preferred in these patients. (Int J Cardiovasc Intervent 2004; 6: 142-147)     

18F-FDG PET/CT分子显像评价缺血性心脏病患者心功能受损与脑葡萄糖代谢的相关性研究

目的从细胞能量代谢的角度评价缺血性心脏病(IHD)患者左心室功能受损与脑葡萄糖代谢水平之间的关系,探索心功能受损患者脑葡萄糖代谢减低的功能区。方法入选于2016年4月至2017年10月在北京安贞医院行99Tcm-甲氧基异丁基异腈(MIBI)门控单光子发射计算机断层扫描/CT(SPECT/CT)心肌灌注显像、18F-脱氧葡萄糖(FDG)门控正电子发射计算机断层成像/CT(PET/CT)心肌葡萄糖代谢显像和脑葡萄糖代谢显像(于3 d内完成所有检查)的IHD患者110例。采用QGS软件分析门控SPECT/CT心肌灌注显像和门控PET/CT心肌葡萄糖代谢显像数据,获取左心室功能参数,包括舒张末期容积(EDV)、收缩末期容积参数(ESV)和左心室射血分数(LVEF)。采用17段-5分法判断心肌存活和心肌梗死,并计算心肌存活范围及心肌梗死范围。根据心肌存活范围将患者分为存活心肌<10%组(44例)、存活心肌10%~<20%组(36例)和存活心肌≥20%组(30例)。采用Pearson相关系数分析心肌存活范围及心肌梗死范围等影像参数与脑葡萄糖代谢水平之间的相关性。采用脑代谢定量分析软件SPM评估全脑葡萄糖代谢标准摄取值的平均值(SUVmean)与小脑葡萄糖代谢SUVmean,并计算靶本比值全脑/小脑(TBR全脑/小脑),即全脑葡萄糖代谢SUVmean与小脑葡萄糖代谢SUVmean的比值。采用SPM软件评估3组之间不同脑功能区脑葡萄糖代谢水平的差异。结果男性101例,年龄(57±10)岁。TBR全脑/小脑与存活心肌范围、梗死心肌范围、门控SPECT/CT及门控PET/CT测得的LVEF有相关性(r值分别为0.280、-0.329、0.188、0.215,P均<0.05)。存活心肌<10%组患者的TBR全脑/小脑为(1.25±0.97),明显低于存活心肌10%~<20%组的1.32±0.17(P<0.05)和存活心肌≥20%组的1.34±0.16(P<0.05)。SPM分析发现,与存活心肌≥20%组比较,存活心肌<10%组患者的楔前叶、额叶、中央后回、顶叶、颞叶等脑功能区的脑葡萄糖代谢水平明显减低。结论IHD患者的左心室功能受损与脑葡萄糖代谢水平存在相关性。心肌存活量少的IHD患者,全脑葡萄糖代谢水平减低,且主要集中在与认知功能相关的脑功能区。     

Clinical importance of viability assessment in chronic ischemic heart failure

Background and hypothesis: Revascularization has provided an effective treatment of depressed left ventricular function in patients with chronically ischemic or “viable” myocardium. Assessment of viable myocardium can be achieved by several noninvasive techniques including dobutamine stress echo or radionuclides such as flurodeoxyglucose (F¹⁸DG). F¹⁸DG uptake studies are based on the assumption that enhanced glucose uptake in areas of diminished blood flow provides evidence of viable myocardium. To determine the clinical utility of viability assessment in the management of chronic ischemic left ventricular dysfunction, we reviewed the findings and short-term treatment of a series of patients referred for heart failure evaluation who had subsequent F¹⁸DG uptake scans. Methods: We retrospectively reviewed 59 consecutive F¹⁸DG viability studies in a series of patients who had documented coronary artery disease and depressed left ventricular function. Single photon emission computerized tomography (SPECT) with F¹⁸DG was performed in the patients and these images were compared to SPECT images of resting myocardial perfusion using thallium, sestamibi, or teboroxime. Clinical decisions based on the results of these scans were obtained from chart review. Thirty-day mortality was determined from chart review or contact with the patient's physician. The patients were divided into those without and with F¹⁸DG uptake consistent with viable ischemic myocardium. Further analysis included subgroups of patients who were advised to undergo transplantation, revascularization, or to continue medical therapy. Results: Of 34 patients referred for cardiac transplantation, 18 had viable myocardium and 13 underwent revascularization. In the entire study group, 34 of 59 (58%) had evidence of viable myocardium and 29 had subsequent revascularization procedures. Thirty-day survival for all revascularization patients was 86%. Conclusion: Assessment of myocardial viability with F¹⁸DG SPECT imaging in patients with ischemic left ventricular dysfunction led to a clinical decision for revascularization in approximately half the patients with severe coronary disease and left ventricular dysfunction who were evaluated for myocardial viability in our institution.