Prognostic implications of myocardial contractile reserve in patients with coronary artery disease and left ventricular dysfunction

Right ventricular dysfunction in left ventricular assist device candidates: is it time to change our prospective?

The use of left ventricular assist devices (LVAD) has significantly increased in the last years, trying to offer a therapeutic alternative to heart transplantation, in light also to the significant heart donor shortage compared to the growing advanced heart failure population. Despite technological improvements in the devices, LVAD-related mortality is still fairly high, with right heart failure being one of the predominant predictors. Therefore, many efforts have been made toward a thorough right ventricular (RV) evaluation prior to LVAD implant, considering clinical, laboratory, echocardiographic, and invasive hemodynamic parameters. However, there is high heterogeneity regarding both which predictor is the strongest as well as the relative cut-off values, and a consensus has not been reached yet, increasing the risk of facing patients in which the distinction between good or poor RV function cannot be surely reached. In parallel, due to technological development and availability of mechanical circulatory support of the RV, LVADs are being considered even in patients with suboptimal RV function. The aim of our review is to analyze the current evidence regarding the role of RV function prior to LVAD and its evaluation, pointing out the extreme variability in parameters that are currently assessed and future prospective regarding new diagnostic tools. Finally, we attempt to gather the available information on the therapeutic strategies to use in the peri-operative phase, in order to reduce the incidence of RV failure, especially in patients in which the preoperative evaluation highlighted some conflicting results with regard to ventricular function.

Multimodality Imaging for Selecting Candidates for CRT: Do We Have a Single Alley to Increase Responders?

Cardiac resynchronization therapy has evolved in recent years to provide a reduction of morbidity and mortality for many patients with heart failure. Its application and optimization is an evolving field and its use requires a multidisciplinary approach for patient and device selection, technical preprocedural planning, and optimization. While echocardiography has always been considered the first line for the evaluation of patients, additional imaging techniques have gained increasing evidence in recent years. Today different details about heart anatomy, function, dissynchrony can be investigated by magnetic resonance, cardiac computed tomography, nuclear imaging, and more, with the aim of obtaining clues to reach a maximal response from the electrical therapy. The purpose of this review is to provide a practical analysis of the single and combined use of different imaging techniques in the preoperative and perioperative phases of cardiac resynchronization therapy, underlining their main advantages, limitations, and information provided.

Left ventricular contractile reserve as a determinant of adverse clinical outcomes: a systematic review

An abnormal left ventricular contractile reserve is often seen in patients undergoing stress echocardiogram and may indicate the presence of obstructive coronary artery disease. The techniques and indexes used to identify abnormal left ventricular contractile response and its prognostic value in the absence of known causes has not been well studied. To describe the characteristics and clinical outcomes associated with an abnormal left ventricular contractile response, we performed a systematic review that identified 27 eligible studies. A diverse range of indices were utilised to measure left ventricular contractile reserve, most commonly Δleft ventricular ejection fraction in 11 studies. Dobutamine stress echocardiogram was the most commonly performed modality (19 studies) followed by exercise stress echocardiogram (4 studies), dipyridamole stress echocardiogram (2 studies), invasive hemodynamic measurement (1 study) and dobutamine stress magnetic resonance imaging (1 study). All but one study demonstrated a significant association between the absence of left ventricular contractile reserve and increased rate of cardiovascular events, cardiac death and all-cause mortality.

Myocardial work and left ventricular contractile reserve during stress echocardiography: An angiographic validation

OBJECTIVE

This study sought to determine the contractile reserve (CR) response to exercise stress echocardiography (ESE) quantified by the novel parameter, non-invasive myocardial work (MW), in subjects with angiographically proven coronary artery disease (CAD).

METHODS

CR was measured by the relative change in ejection fraction (EF), global longitudinal strain (GLS) and MW indices from rest to peak exercise in 304 patients referred for clinically indicated ESE. Positive ESE patients proceeded to coronary angiography and further risk stratified based on either percutaneous or surgical intervention.

RESULTS

CR_GLS and global work index (CR_GWI ) significantly decreased with exercise induced ischemia and angiographically proven significant CAD (CR_GLS -1.6±3.5%; CR_GWI -8.6±511 mm Hg% decrement, p < 0.001) compared to non-ischemic patients (CR_GLS 1.4±2.2%; CR_GWI 398±404 mm Hg% improvement). Global constructive work (CR_GCW ) was significantly higher (p < 0.0001) in non-ischemic (818±457 mm Hg%) and blunted in ischemic patients (208±550 mm Hg%). CR_GCW (AUC .81; 95%CI:.75-.86) demonstrated the most association for inducible ischemia followed by CR_GLS (AUC .75; 95%CI:.69-.80), CR_GWI (AUC .73, 95%CI:.67-.79) and CR_EF (AUC .71; 95%CI:.65-.77, p < 0.001). Subgroup analysis showed patients requiring surgical revascularization demonstrated a significantly lower CR_GWE (-11.5±7.6%, p < 0.05) as a result of reduced CR_GCW (281±573 mm Hg%, p < 0.05) and increased global wasted work (CR_GWW , 289±151 mm Hg%, p = 0.09).

CONCLUSION

Multivessel disease requiring surgical revascularization have the greatest reduction in CR. MW may potentially improve detection of ischemia and further risk stratification during ESE to maximize the benefits of revascularization.

Longitudinal metabolic profiling of cardiomyocytes derived from human-induced pluripotent stem cells

Human-induced pluripotent stem cells (h-iPSCs) are a unique in vitro model for cardiovascular research. To realize the potential applications of h-iPSCs-derived cardiomyocytes (CMs) for drug testing or regenerative medicine and disease modeling, characterization of the metabolic features is critical. Here, we show the transcriptional profile during stages of cardiomyogenesis of h-iPSCs-derived CMs. CM differentiation was not only characterized by the expression of mature structural components (MLC2v, MYH7) but also accompanied by a significant increase in mature metabolic gene expression and activity. Our data revealed a distinct substrate switch from glucose to fatty acids utilization for ATP production. Basal respiration and respiratory capacity in 9 days h-iPSCs-derived CMs were glycolysis-dependent with a shift towards a more oxidative metabolic phenotype at 14 and 28 day old CMs. Furthermore, mitochondrial analysis characterized the early and mature forms of mitochondria during cardiomyogenesis. These results suggest that changes in cellular metabolic phenotype are accompanied by increased O₂ consumption and ATP synthesis to fulfill the metabolic needs of mature CMs activity. To further determine functionality, the physiological response of h-iPSCs-derived CMs to β-adrenergic stimulation was tested. These data provide a unique in vitro human heart model for the understanding of CM physiology and metabolic function which may provide useful insight into metabolic diseases as well as novel therapeutic options.

Myocardial Viability Testing by Positron Emission Tomography: Basic Concepts, Mini-Review of the Literature and Experience From a Tertiary PET Center

Ischemic heart disease ranges in severity from slightly reduced myocardial perfusion with preserved contractile function to chronic occlusion of coronary arteries with myocardial cells replaced by acontractile scar tissue-ischemic heart failure (iHF). Progression towards scar tissue is thought to involve a period in which the myocardial cells are acontractile but still viable despite severely reduced perfusion. This state of reduced myocardial function that can be reversed by revascularization is termed "hibernation." The concept of hibernating myocardium in iHF has prompted an increasing amount of requests for preoperative patient workup, but while the concept of viability is widely agreed upon, no consensus on clinical testing of hibernation has been established. Therefore, a variety of imaging methods have been used to assess hibernation including morphology based (MRI and ultrasound), perfusion based (MRI, SPECT, or PET) and/or methods to assess myocardial metabolism (PET). Regrettably, the heterogeneous body of literature on the subject has resulted in few robust prospective clinical trials designed to assess the impact of preoperative viability testing prior to revascularization. However, the PARR-2 trial and sub-studies has indicated that >5% hibernating myocardium favors revascularization over optimized medical therapy. In this paper, we review the basic concepts and current evidence for using PET to assess myocardial hibernation and discuss the various methodologies used to process the perfusion/metabolism PET images. Finally, we present our experience in conducting PET viability testing in a tertiary referral center.

Dobutamine echocardiography for assessment of viability in the current era

PURPOSE OF REVIEW

Studies from the 1990s and early 2000s documented the utility of dobutamine echocardiography for the prediction of functional recovery and prognosis with revascularization. The results of The Surgical Treatment of Ischemic Heart Failure (STICH) trial called into question the value of viability assessment using dobutamine echocardiography. The purpose of this review is to re-examine the literature on dobutamine echocardiography, put into context the STICH results, and provide insight into the current role of dobutamine echocardiography viability testing.

RECENT FINDINGS

In contrast to the results of previous nonrandomized trials, the STICH trial showed that patients with viability defined by nuclear perfusion imaging or dobutamine echocardiography did not have improved survival with CABG compared with optimal medical therapy. Viability by dobutamine echocardiography was defined as the presence of contractile reserve in at least five segments with baseline dysfunction. The results of dobutamine echocardiography studies published before and after initiation of the STICH trial suggest that the definition of viability utilized in that trial may be suboptimal for assessment of improvement in global function and prognosis in patients undergoing revascularization. Assessment of global contractile reserve using wall motion score (WMS) or ejection fraction may be superior to utilization of a binary definition of viability confined to assessment of contractile reserve in a fixed number of segments because these indices provide information on both the magnitude and extent of contractile reserve of the entire left ventricle (LV).

SUMMARY

Assessment of WMS or ejection fraction with dobutamine echocardiography may be the optimal means of evaluating the impact of viability on prognosis.Video abstract http://links.lww.com/HCO/A56.

Low dose wall motion score predicts the short and long-term benefit of surgical revascularization in patients with ischemic left ventricular dysfunction

We investigated the influence of the extent of viability using low dose dobutamine wall motion score index (WMS) on the survival benefit of surgical revascularization (CABG) versus medical therapy. In the STICH trial, viability assessment was not helpful in determining the benefit of CABG. However, the extent of viable myocardium with contractile function was not assessed in the trial. Dobutamine echocardiography was performed in 250 patients with ischemic left ventricular dysfunction (125-medically treated, 125-CABG). The mean ejection fraction (EF) was 32% in both groups. WMS during low dose dobutamine infusion was used to classify patients into groups with extensive (WMS < 2.00), intermediate (WMS 2.00-2.49), and limited (WMS ≥ 2.50) viability. Survival free of cardiac death was assessed at 2 years and for the complete duration of follow-up. There were 44 (35.2%) and 67 (53.6%) cardiac deaths in the revascularized and medically treated patients respectively (follow-up of 5.7 ± 5.8 years). Revascularized and medically treated patients with extensive viability had similar 2-year survival (p = 0.567) but revascularized patients had improved long-term survival (p = 0.0001). In those with intermediate viability, revascularization improved both 2 year (p = 0.014) and long-term survival (p = 0.0001). In patients with limited viability, 2-year survival was worse in revascularized patients (p = 0.04) and long-term survival was similar (p = 0 .25) in revascularized and medically treated groups. Patients with extensive and intermediate amounts of viability have improved survival with CABG but those with limited viability have poorer short-term outcome and no long-term benefit.

[The Clinical use of Stress Echocardiography in Ischemic Heart Disease Cardiovascular Ultrasound (2017)15:7. Translation authors: Arystan A.Zh., Fettser D.V.]

Stress echocardiography is an established technique for the assessment of extent and severity of coronary artery disease. The combination of echocardiography with a physical, pharmacological or electrical stress allows detecting myocardial ischemia with an excellent accuracy. A transient worsening of regional function during stress is the hallmark of inducible ischemia. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging or magnetic resonance, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician. The evidence on its clinical impact has been collected over 35 years, based on solid experimental, pathophysiological, technological and clinical foundations. There is the need to implement the combination of wall motion and coronary flow reserve, assessed in the left anterior descending artery, into a single test. The improvement of technology and in imaging quality will make this approach more and more feasible. The future issues in stress echo will be the possibility of obtaining quantitative information translating the current qualitative assessment of regional wall motion into a number. The next challenge for stress echocardiography is to overcome its main weaknesses: dependence on operator expertise, the lack of outcome data (a widespread problem in clinical imaging) to document the improvement of patient outcomes. This paper summarizes the main indications for the clinical applications of stress echocardiography to ischemic heart disease.

Role of cardiovascular imaging in cardiac resynchronization therapy: a literature review

: Cardiac resynchronization therapy (CRT) is an established treatment in patients with symptomatic drug-refractory heart failure and broad QRS complex on the surface ECG. Despite the presence of either mechanical dyssynchrony or viable myocardium at the site where delivering left ventricular pacing being necessary conditions for a successful CRT, their direct assessment by techniques of cardiovascular imaging, though feasible, is not recommended in clinical practice by the current guidelines. Indeed, even though there is growing body of data providing evidence of the additional value of an image-based approach as compared with routine approach in improving response to CRT, these results should be confirmed in prospective and large multicentre trials before their impact on CRT guidelines is considered.

Echocardiography during preload stress for evaluation of right ventricular contractile reserve and exercise capacity in pulmonary hypertension

OBJECTIVES

Pulmonary hypertension (PH) is characterized by marked and sustained elevation of pulmonary vascular resistance and pulmonary artery pressure, and subsequent right-sided heart failure. Right ventricular (RV) function and exercise capacity have been recognized as important prognostic factors for PH. Our aim was to investigate RV contractile reserve and exercise capacity during a leg-positive pressure (LPP) maneuver.

METHODS

The study population comprised 43 PH patients and 17 normal controls. All patients underwent echocardiography at rest and during LPP stress. Exercise capacity was assessed by 6-minute walk distance for PH patients. RV relative wall thickness was calculated from dividing by RV free wall thickness by basal RV linear dimensions at end-diastole. RV function was calculated by averaging peak speckle-tracking longitudinal strain from the RV free wall. RV contractile reserve was assessed as the difference in RV free wall strain at rest and during LPP stress. Changes in left ventricular stroke volume (ΔSV) during LPP stress were also calculated.

RESULTS

ΔSV and RV contractile reserve of PH patients were significantly lower than of controls (3.6 ± 6.0 mL vs 8.5 ± 2.3 mL, and 8.2 ± 11.9% vs 14.5 ± 6.6%; both P < 0.01). RV contractile reserve of PH patients with ΔSV <3.3 mL was significantly lower than of PH patients with ΔSV >3.3 mL (3.9 ± 13.2% vs 12.3 ± 8.9%; P = 0.02). ΔSV had also significant correlation with 6-minute walk distance (r = 0.42, P = 0.006). Multivariate regression analysis showed that RV relative wall thickness was an independent determinant parameter of ΔSV during LPP stress for PH patients (β = 3.2, P = 0.003).

CONCLUSIONS

Preload stress echocardiography in response to LPP maneuver, a noninvasive and easy-to-use procedure for routine clinical use, proved to be useful for the assessment of RV contractile reserve and exercise capacity of PH patients.

Heart failure with recovered ejection fraction

Substantial or complete myocardial recovery occurs in many patients with heart failure (HF). HF patients with myocardial recovery or recovered left ventricular (LV) ejection fraction (EF; HFrecEF) are a distinct population of HF patients with different underlying etiologies, comorbidities, response to therapies, and outcomes compared with HF patients with persistent reduced or preserved EF. Improvement in LVEF has been systematically linked to improved quality of life, and lower rehospitalization rates and mortality. However, the mortality and morbidity in HFrecEF patients remain higher than those in the normal population. Currently, data to guide the management of HFrecEF patients are lacking. This review discusses specific characteristics, pathophysiology, and clinical implications for HFrecEF.

Heart Failure with Myocardial Recovery - The Patient Whose Heart Failure Has Improved: What Next?

In an important number of heart failure (HF) patients substantial or complete myocardial recovery occurs. In the strictest sense, myocardial recovery is a return to both normal structure and function of the heart. HF patients with myocardial recovery or recovered ejection fraction (EF; HFrecEF) are a distinct population of HF patients with different underlying etiologies, demographics, comorbidities, response to therapies and outcomes compared to HF patients with persistent reduced (HFrEF) or preserved ejection fraction (HFpEF). Improvement of left ventricular EF has been systematically linked to improved quality of life, lower rehospitalization rates and mortality. However, mortality and morbidity in HFrecEF patients remain higher than in the normal population. Also, persistent abnormalities in biomarker and gene expression profiles in these patients lends weight to the hypothesis that pathological processes are ongoing. Currently, there remains a lack of data to guide the management of HFrecEF patients. This review will discuss specific characteristics, pathophysiology, clinical implications and future needs for HFrecEF.

The clinical use of stress echocardiography in ischemic heart disease

Stress echocardiography is an established technique for the assessment of extent and severity of coronary artery disease. The combination of echocardiography with a physical, pharmacological or electrical stress allows to detect myocardial ischemia with an excellent accuracy. A transient worsening of regional function during stress is the hallmark of inducible ischemia. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging or magnetic resonance, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician.

The evidence on its clinical impact has been collected over 35 years, based on solid experimental, pathophysiological, technological and clinical foundations. There is the need to implement the combination of wall motion and coronary flow reserve, assessed in the left anterior descending artery, into a single test. The improvement of technology and in imaging quality will make this approach more and more feasible. The future issues in stress echo will be the possibility of obtaining quantitative information translating the current qualitative assessment of regional wall motion into a number. The next challenge for stress echocardiography is to overcome its main weaknesses: dependance on operator expertise, the lack of outcome data (a widesperad problem in clinical imaging) to document the improvement of patient outcomes. This paper summarizes the main indications for the clinical applications of stress echocardiography to ischemic heart disease.

Prognostic Value of Viable Myocardium in Patients with Non-Q-wave and Q-wave Myocardial Infarction

This study assessed the amount and prognostic value of myocardial viability in patients with non-Q-wave myocardial infarction (NQMI) and Q-wave myocardial infarction (QMI). A total of 175 patients with MI and an ejection fraction ≤ 45% underwent dobutamine stress echocardiography. On the basis of clinical criteria and myocardial viability, 110 patients were revascularized. The amount of viable myocardium and the clinical outcome were compared in the NQMI and QMI groups. Patients with NQMI exhibited a larger amount of viable myocardium compared with those with QMI. The mortality rate was 6% in patients with NQMI with viable myocardium and subsequent revascularization, 33% in patients with NQMI without viable myocardium or revascularization, 27% in patients with QMI with viable myocardium and subsequent revascularization, and 33% in patients with QMI without viable myocardium or revascularization. In conclusion, our data suggest that patients with NQMI and viable myocardium have the best prognosis after revascularization.

Intravenous Followed by X-ray Fused with MRI-Guided Transendocardial Mesenchymal Stem Cell Injection Improves Contractility Reserve in a Swine Model of Myocardial Infarction

The aim of this study is to determine the effects of early intravenous (IV) infusion later followed by transendocardial (TE) injection of allogeneic mesenchymal stem cells (MSCs) following myocardial infarction (MI). Twenty-four swine underwent balloon occlusion reperfusion MI and were randomized into 4 groups: IV MSC (or placebo) infusion (post-MI day 2) and TE MSC (or placebo) injection targeting the infarct border with 2D X-ray fluoroscopy fused to 3D magnetic resonance (XFM) co-registration (post-MI day 14). Continuous ECG recording, MRI, and invasive pressure-volume analyses were performed. IV MSC plus TE MSC treated group was superior to other groups for contractility reserve (p = 0.02) and freedom from VT (p = 0.03) but had more lymphocytic foci localized to the peri-infarct region (p = 0.002). No differences were observed in post-MI remodeling parameters. IV followed by XFM targeted TE MSC therapy improves contractility reserve and suppresses VT but does not affect post-MI remodeling and may cause an immune response.

Prognostic Value of Stress Echocardiography in Patients With Low-Intermediate or High Short-Term (10 Years) Versus Low (<39%) or High (≥39%) Lifetime Predicted Risk of Cardiovascular Disease According to the American College of Cardiology/American Heart Association 2013 Cardiovascular Risk Calculator

This study evaluates the prognostic value of stress echocardiography (Secho) in short-term (10 years) and lifetime atherosclerotic cardiovascular disease risk-defined groups according to the American College of Cardiology/American Heart Association 2013 cardiovascular risk calculator. The ideal risk assessment and management of patients with low-to-intermediate or high short-term versus low (<39%) or high (≥39%) lifetime CV risk is unclear. The purpose of this study was to evaluate the prognostic value of Secho in short-term and lifetime CV risk-defined groups. We evaluated 4,566 patients (60 ± 13 years; 46% men) who underwent Secho (41% treadmill and 59% dobutamine) with low-intermediate short-term (<20%) risk divided into low (<39%, n = 368) or high (≥39%, n = 661) lifetime CV risk and third group with high short-term risk (≥20%, n = 3,537). Follow-up (3.2 ± 1.5 years) for nonfatal myocardial infarction (n = 102) and cardiac death (n = 140) were obtained. By univariate analysis, age (p <0.001) and ≥3 new ischemic wall motion abnormalities (WMAs, p <0.001) were significant predictors of cardiac events. Cumulative survival in patients was significantly worse in patients with ≥3 WMA versus <3 WMA in low-intermediate short-term and low (3.3% vs 0.3% per year, p <0.001) or high (2.0% vs 0% per year, p <0.001) lifetime risk and also in those with high short-term CV risk group (3.5% vs 1.0% per year, p <0.001). Multivariate Cox proportional hazards analysis identified ≥3 new ischemic WMAs as the strongest predictor of cardiac events (hazard ratio 3.0, 95% confidence interval 2.3 to 3.9, p <0.001). In conclusion, Secho results (absence or presence of ≥3 new ischemic segments) can further refine risk assessment in patients with low-intermediate or high short-term versus low or high lifetime cardiovascular risk. Event rate with normal Secho is low (≤1% per year) but higher in patients with high short-term CV risk by the American College of Cardiology/American Heart Association 2013 cardiovascular risk calculator.

Utilization of stress echocardiography in patients with multivessel coronary artery disease

OBJECTIVE

The purpose of this study was to evaluate the role of stress echocardiography in the risk stratification and prognosis of patients with multivessel coronary artery disease (CAD).

BACKGROUND

Stress echocardiography is an established technique for diagnosis, risk stratification, and prognosis of patients with known or suspected CAD.

METHODS

We evaluated 409 patients (65 ± 10 years; 63% men) referred for stress echocardiography (45% treadmill, 55% dobutamine), who underwent stress echocardiography and coronary angiography within 3 months. All patients had multivessel CAD as defined by coronary stenosis (≥50% left main or ≥70% in two or more major epicardial vessels or branches). The left ventricle was divided into 16 segments and was scored on a five-point scale of wall motion. Patients with abnormal results on stress echocardiography were defined as those with stress-induced ischemia (increase in wall motion score of ≥1 grade).

RESULTS

Follow-up (3.1 ± 1.3 years) for nonfatal myocardial infarction (n = 35) and cardiac death (n = 25) was obtained. In patients with multivessel CAD, stress echocardiography effectively risk-stratified normal (no ischemia, n = 83) vs. abnormal (ischemia, n = 326) groups for cardiac events (event rate 1.9 vs. 5.4%/year; P < 0.01). Multivariable Cox proportional-hazards regression model identified stress-induced ischemia (hazard ratio 5.5, 95% confidence interval 1.9-15.9, P = 0.002) as the most significant predictor of adverse cardiac events. A stepwise Cox proportional-hazards model demonstrated significant incremental prognostic value of stress echocardiography over clinical variables, stress electrocardiography and resting left ventricular function (P < 0.0001), with the highest global chi-square value.

CONCLUSIONS

In patients with angiographically significant multivessel CAD, despite normal-stress echocardiography, there was an intermediate cardiac event rate (1.9%/year); abnormal-stress echocardiography identified a high-risk group (5.4%/year); and stress echocardiography provided incremental prognostic value for risk stratification and prediction of cardiac events.

Differential response of LV sublayer twist during dobutamine stress echocardiography as a novel marker of contractile reserve after acute myocardial infarction: relationship with follow-up LVEF improvement

AIMS

Dobutamine stress echocardiography (DSE) is frequently performed to assess left ventricular (LV) contractile reserve in patients following myocardial infarction (STEMI). Given that resting LV sublayer twist assessment has been proposed as a marker of infarct transmurality, this study aimed to investigate whether response of LV subepicardial twist on DSE represents a novel quantitative marker of contractile reserve.

METHODS AND RESULTS

First STEMI patients treated with primary percutaneous coronary intervention with a resting wall motion abnormality in greater than or equal to two segment(s) at 3 months who underwent full protocol DSE were included. Two-dimensional speckle-tracking was used to calculate LV subepi- and subendocardial twist-defined as the net difference (in degrees) of apical and basal rotation for each sublayer-at rest and peak-dose stages. Primary end point was a ≥5% absolute LV ejection fraction (LVEF) improvement between 3 and 6 months. In total, 61 patients (mean age 61 ± 12, 87% male) were included, of whom 48% (n = 29) demonstrated follow-up LVEF improvement. Mean change in both LV subepicardial (ΔLVsubepi) twist (2.4 ± 3.0 vs. 0.00 ± 2.0°, P = 0.001) and LV subendocardial (ΔLVsubendo) twist (2.7 ± 4.5 vs. 0.25 ± 4.5°, P = 0.04) from rest to peak was significantly higher in LVEF improvers. ΔLVsubepi (odds ratio, OR 1.5, 95% confidence interval, CI 1.1-2.0, P = 0.007), but not ΔLVsubendo (OR 1.1, 95% CI 0.99-1.3, P = 0.07), twist was independently associated with follow-up LVEF improvement following adjustment for baseline LVEF and β-blockade.

CONCLUSION

In post-STEMI patients with resting regional dysfunction, the response of LV subepicardial twist on DSE is associated with follow-up LV function improvement, suggesting recruitment in subepicardial function following STEMI reflects greater extent of contractile reserve.

Dobutamine stress for evaluation of right ventricular reserve in pulmonary arterial hypertension

Right ventricular contractile response to pharmacological stress in pulmonary arterial hypertension (PAH) has not been characterised. We evaluated right ventricular contractile reserve in adults with PAH using dobutamine stress echocardiography.

16 PAH patients and 18 age-matched controls underwent low-dose dobutamine stress echocardiography. Contractile reserve was assessed by the change (Δ; peak stress minus rest value) in tricuspid annular plane systolic excursion (TAPSE) and tricuspid annular systolic velocity (S′). A subgroup of 13 PAH patients underwent treadmill cardiopulmonary exercise testing for peak oxygen uptake (V′O2peak).

At rest, TAPSE and S′ were reduced in the PAH group compared with controls (1.7±0.4 versus 2.4±0.2 cm and 9.7±2.6 versus 12.5±1.2 cm·s−1, respectively; p<0.05). Contractile reserve was markedly attenuated in PAH compared to controls (ΔTAPSE 0.1±0.2 versus 0.6±0.3 cm and ΔS′ 4.6±2.8 versus 11.2±3.6 cm·s−1; p<0.0001). In the sub-group of PAH patients with preserved right ventricular systolic function at rest, contractile reserve remained depressed compared to controls. V′O2peak was significantly correlated with ΔS′ (r=0.87, p=0.0003) and change in stroke volume (r=0.59, p=0.03).

Dobutamine stress can reveal sub-clinical reduction in right ventricular contractile reserve in patients with PAH. A correlation with exercise capacity suggests potential clinical value beyond resting measurements.

Late gadolinium enhancement magnetic resonance imaging for the assessment of myocardial infarction: comparison of image quality between single and double doses of contrast agents

To compare the image quality of late gadolinium enhancement (LGE) cardiac magnetic resonance imaging (CMR) using a single dose of gadolinium contrast agent versus the conventional double dose for assessing myocardial infarction. This retrospective study examined 37 patients with chronic myocardial infarction who underwent LGE CMR using both inversion recovery (IR)-turbo fast low-angle shot magnitude-reconstructed and phase-sensitive images with two different dosages of gadolinium contrast agent: a single dose of 0.1 mmol/kg gadolinium-DTPA in 17 patients and a double dose of 0.2 mmol/kg in 20 patients. The contrast-to-noise ratio (CNR) and visual conspicuity between infarct and normal myocardium (CNRinfarct-normal, conspicuityinfarct-normal) and between infarct and left ventricular cavity (CNRinfarct-LVC, conspicuityinfarct-LVC) were compared. Interobserver agreement for the maximal transmural extent of infarction was also evaluated. CNRinfarct-normal was significantly higher with double-dose gadolinium contrast agent (15.5 ± 20.7 vs. 40.4 ± 16.1 in magnitude images and 9.5 ± 2.8 vs. 11.2 ± 2.7 in phase-sensitive images, P < 0.001) while conspicuityinfarct-normal showed no significant difference between the two groups (P > 0.05). Both CNRinfarct-LVC (7.7 ± 10.7 vs. -6.6 ± 19.0 in magnitude images and 4.1 ± 2.3 vs. -0.4 ± 4.1 in phase-sensitive images, P < 0.05) and conspicuityinfarct-LVC were significantly better with single-dose gadolinium contrast. Interobserver agreement for assessing the transmural extent of infarction was moderate in both groups: 0.591 for single-dose and 0.472 for double-dose. LGE CMR using a single dose of gadolinium contrast agent showed significantly better contrast between infarcted myocardium and left ventricular cavity lumen without a significant decrease in visual contrast between infarcted myocardium and normal myocardium, compared to a double dose.

Left ventricular twist during dobutamine stress echocardiography after acute myocardial infarction: association with reverse remodeling

Left ventricular (LV) twist is emerging as a marker of global LV contractility after acute myocardial infarction (AMI). This study aimed to describe stress-induced changes in LV twist during dobutamine stress echocardiography (DSE) after AMI and investigate their association with LV reverse remodeling at 6 months follow-up. In 82 consecutive first AMI patients (61 ± 12 years, 85 % male) treated with primary percutaneous coronary intervention, DSE was performed at 3 months follow-up. Two-dimensional speckle-tracking-derived apical and basal rotation and LV twist were calculated at rest, low- and peak-dose stages. LV reverse remodeling was defined as ≥10 % decrease in LV end-systolic volume between baseline and 6 months follow-up. Patterns of LV twist response on DSE consisted of either a progressive increase throughout each stage (n = 18), an increase at either low- or peak-dose (n = 53) or no significant increase (n = 11). LV reverse remodeling occurred in 28 (34 %) patients, who showed significantly higher peak-dose LV twist (8.51° vs. 6.69°, p = 0.03) and more frequently progressive LV twist increase from rest to peak-dose (39 vs. 13 %, p < 0.01) compared to patients without reverse remodeling. Furthermore, increase in LV twist from rest to peak-dose was the only independent predictor of LV reverse remodeling at 6 months follow-up (OR 1.3, 95 % CI 1.1-1.5, p = 0.005). Both the pattern of progressive increase in LV twist and the stress-induced increment in LV twist on DSE are significantly associated with LV reverse remodeling at 6 month follow-up after AMI, suggesting its potential use as a novel marker of contractile reserve.

Feasibility and prognostic value of stress echocardiography in obese, morbidly obese, and super obese patients referred for bariatric surgery

BACKGROUND

Stress echocardiography (SE) is clinically used in the risk stratification and prognosis of patients with coronary artery disease. Due to multiple comorbidities, obese patients have increased risk of adverse cardiovascular events perioperatively in noncardiac surgery. The aim of this study was to investigate the feasibility of SE in morbidly obese patients undergoing bariatric surgery.

METHODS

Consecutive patients referred for SE for preoperative evaluation prior to bariatric surgery from January 2002 to July 2011 formed the study cohort. Contrast was used to define the endocardial border in patients with poor acoustic windows. All-cause mortality data were obtained from Social Security Death Index.

RESULTS

Six hundred fifty-two patients (47 ± 10 years, 84% females) with the mean follow-up of 3.0 ± 2.7 years and mean body mass index (BMI) of 47 ± 9 kg/m² were included in this analysis. Dobutamine SE was performed in 65% of patients compared to exercise SE in 35%. Patients with higher BMI were more likely to undergo dobutamine SE (P < 0.0001). Similarly, incidence of poor acoustic windows and contrast use was higher in those with increased BMI (P < 0.001). Contrast use was higher in patients undergoing dobutamine SE (39%) versus exercise (25%), (P = 0.002). 19 patients (3%) had an abnormal SE and 8 patients (1.2%) died during the follow-up period.

CONCLUSION

Stress echocardiography is feasible in the morbidly obese patients. Patients with higher BMI were more likely to undergo dobutamine SE and have higher incidence of poor acoustic windows and contrast use.

Effect of body mass index on outcome in patients with suspected coronary artery disease referred for stress echocardiography

In patients with hypertension, heart failure, or coronary artery disease (CAD), obese patients have been shown to have a lower cardiac event rate compared with normal weight counterparts. This phenomenon has been termed the "obesity paradox." We sought to determine whether the obesity paradox exists in a cohort of patients referred for stress echocardiography. We evaluated 4,103 patients with suspected CAD (58 ± 13 years; 42% men) undergoing stress echocardiography (52% exercise and 47% dobutamine). Patients were divided into 3 groups on the basis of body mass index (BMI): 18.5 to 24.9, 25 to 29.9, and >30 kg/m(2). During the follow-up of 8.2 ± 3.6 years, there were 683 deaths (17%). Myocardial ischemia was present in 21% of the population. Myocardial ischemia was more prevalent in patients with a BMI of 18.5 to 24.9 kg/m(2) (26%) than those with a BMI of 25 to 29.9 kg/m(2) (21%) and >30 kg/m(2) (18%). Patients with a BMI of >30 kg/m(2) had the lowest death rate (1.2%/year) compared with those with a BMI of 25 to 29.9 kg/m(2) (1.75%/year) and 18.5 to 24.9 kg/m(2) (2.9%/year; p <0.001). After adjusting for significant clinical variables including exercise capacity, patients with higher BMI (>30 kg/m(2) and 25 to 29.9 kg/m(2)) had less risk of mortality compared with those with a BMI of 18.5 to 24.9 kg/m(2) (hazard ratio 0.58, 95% confidence interval 0.47 to 0.72, p <0.0001 and hazard ratio 0.69, 95% confidence interval 0.57 to 0.82, p <0.0001, respectively). In conclusion, higher survival rate in patients with higher BMI as previously described in patients with hypertension, heart failure, and CAD extends to patients with suspected CAD referred for stress echocardiography, independent of exercise capacity.

Activation of β-adrenoceptors by dobutamine may induce a higher expression of peroxisome proliferator-activated receptors δ (PPARδ) in neonatal rat cardiomyocytes

Recent evidence showed the role of peroxisome proliferator-activated receptors (PPARs) in cardiac function. Cardiac contraction induced by various agents is critical in restoring the activity of peroxisome proliferator-activated receptors δ (PPARδ) in cardiac myopathy. Because dobutamine is an agent widely used to treat heart failure in emergency setting, this study is aimed to investigate the change of PPARδ in response to dobutamine. Neonatal rat cardiomyocytes were used to examine the effects of dobutamine on PPARδ expression levels and cardiac troponin I (cTnI) phosphorylation via Western blotting analysis. We show that treatment with dobutamine increased PPARδ expression and cTnI phosphorylation in a time- and dose-dependent manner in neonatal rat cardiomyocytes. These increases were blocked by the antagonist of β1-adrenoceptors. Also, the action of dobutamine was related to the increase of calcium ions and diminished by chelating intracellular calcium. Additionally, dobutamine-induced action was reduced by the inhibition of downstream messengers involved in this calcium-related pathway. Moreover, deletion of PPARδ using siRNA generated the reduction of cTnI phosphorylation in cardiomyocytes treated with dobutamine. Thus, we concluded that PPARδ is increased by dobutamine in cardiac cells.

Prognostic value of stress echocardiogram in patients with angiographically significant coronary artery disease

The purpose of this study was to evaluate the prognostic value of stress echocardiography in patients with angiographically significant coronary artery disease (CAD). Two hundred sixty patients (mean age 63 ± 10 years, 58% men) who underwent stress echocardiography (41% treadmill, 59% dobutamine) and coronary angiography within 3 months and without intervening coronary revascularization were evaluated. All patients had significant CAD as defined by coronary stenosis ≥70% in major epicardial vessels or branches (45% had single-vessel disease, and 55% had multivessel disease). The left ventricle was divided into 16 segments and scored on a 5-point scale of wall motion. Patients with abnormal results on stress echocardiography were defined as those with stress-induced ischemia (increase in wall motion score of ≥1 grade). Follow-up (3.1 ± 1.2 years) for nonfatal myocardial infarction (n = 23) and cardiac death (n = 6) was obtained. In patients with angiographically significant CAD, stress echocardiography effectively risk stratified normal (no ischemia, n = 91) in contrast to abnormal (ischemia, n = 169) groups for cardiac events (event rate 1.0%/year vs 4.9%/year, p = 0.01). Multivariate logistic regression analysis identified multivessel CAD (hazard ratio 2.53, 95% confidence interval 1.16 to 5.51, p = 0.02) and number of segments in which ischemia was present (hazard ratio 4.31, 95% confidence interval 1.29 to 14.38, p = 0.01) as predictors of cardiac events. A Cox proportional-hazards model for cardiac events showed small, significant incremental value of stress echocardiography over coronary angiography (p = 0.02) and the highest global chi-square value for both (p = 0.004). In conclusion, in patients with angiographically significant CAD, (1) normal results on stress echocardiography conferred a benign prognosis (event rate 1.0%/year), and (2) stress echocardiographic results (no ischemia vs ischemia) added incremental prognostic value to coronary angiographic results, and (3) stress echocardiography and coronary angiography together provided additive prognostic value, with the highest global chi-square value.

Inotropic contractile reserve can risk-stratify patients with HIV cardiomyopathy: a dobutamine stress echocardiography study

OBJECTIVES

The purpose of this study was to assess whether inotropic contractile reserve (ICR) during dobutamine stress echocardiography (DSE) could risk-stratify patients with human immunodeficiency virus (HIV) cardiomyopathy and predict improvement of left ventricular ejection fraction (LVEF).

BACKGROUND

HIV cardiomyopathy is an important cause of heart failure and death. ICR is associated with better survival and improvement of LVEF in patients with ischemic and nonischemic cardiomyopathies. However, the prognostic value of ICR in patients with HIV cardiomyopathy is unknown.

METHODS

Patients with HIV cardiomyopathy and a LVEF <45% who were referred for DSE were enrolled. ICR was evaluated by the delta wall motion score index (ΔWMSI), calculated as the difference between rest and peak WMSI. Patients were followed for cardiac death and change in LVEF on follow-up.

RESULTS

Sixty patients (75% men; age, 54 ± 9 years) with HIV cardiomyopathy (mean LVEF, 28 ± 11%) formed the study group. After 2.4 ± 2.1 years, 11 cardiac deaths occurred (event rate of 7.6%/year). A receiver-operating characteristic curve identified a ΔWMSI of 0.38 as an optimal cut point for the presence of ICR, with a specificity of 88% and a sensitivity of 73% for the prediction of cardiac death. On univariable analysis, the absence of ICR (hazard ratio: 6.6; 95% confidence interval: 1.93 to 22.62; p = 0.003) and New York Heart Association functional class IV (hazard ratio: 7.2; 95% confidence interval: 2.20 to 23.65; p = 0.001) were the only predictors of cardiac death. After 2.1 ± 1.8 years, 41 patients had a follow-up echocardiogram. LVEF improvement from baseline occurred in 23 patients (56%), more so in patients with ICR than without ICR. A ΔWMSI of 0.59 predicted improvement in the LVEF with a specificity of 78% and a sensitivity of 74%.

CONCLUSIONS

The presence of ICR during DSE can risk-stratify and predict subsequent improvement in LVEF in patients with HIV cardiomyopathy.

Prevalence of scarred and dysfunctional myocardium in patients with heart failure of ischaemic origin: a cardiovascular magnetic resonance study

BACKGROUND

Cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE) can provide unique data on the transmural extent of scar/viability. We assessed the prevalence of dysfunctional myocardium, including partial thickness scar, which could contribute to left ventricular contractile dysfunction in patients with heart failure and ischaemic heart disease who denied angina symptoms.

METHODS

We invited patients with ischaemic heart disease and a left ventricular ejection fraction < 50% by echocardiography to have LGE CMR. Myocardial contractility and transmural extent of scar were assessed using a 17-segment model.

RESULTS

The median age of the 193 patients enrolled was 70 (interquartile range: 63-76) years and 167 (87%) were men. Of 3281 myocardial segments assessed, 1759 (54%) were dysfunctional, of which 581 (33%) showed no scar, 623 (35%) had scar affecting ≤50% of wall thickness and 555 (32%) had scar affecting > 50% of wall thickness. Of 1522 segments with normal contractile function, only 98 (6%) had evidence of scar on CMR. Overall, 182 (94%) patients had ≥1 and 107 (55%) patients had ≥5 segments with contractile dysfunction that had no scar or ≤50% transmural scar suggesting viability.

CONCLUSIONS

In this cohort of patients with left ventricular systolic dysfunction and ischaemic heart disease, about half of all segments had contractile dysfunction but only one third of these had > 50% of the wall thickness affected by scar, suggesting that most dysfunctional segments could improve in response to an appropriate intervention.

The concept of ventricular reserve in heart failure and pulmonary hypertension: an old metric that brings us one step closer in our quest for prediction

PURPOSE OF REVIEW

Ventricular reserve is emerging a strong predictor of outcome in heart failure and cardiovascular disease. Ventricular reserve is the term used to describe the extent of increase or change in ventricular function that occurs during exercise or pharmacological stress (typically with dobutamine).

RECENT FINDINGS

The interest in ventricular reserve lies in its ability to assess viability in coronary artery disease, to predict clinical outcome and response to therapy in patients with heart failure and to screen patients for early cardiovascular disease.

SUMMARY

In this paper, we will review the emerging role of ventricular reserve in heart failure and pulmonary hypertension. We will also explore the mechanisms involved in the pathophysiology of impaired ventricular reserve and discuss future directions of research in the field.

Myocardial viability and survival in ischemic left ventricular dysfunction

BACKGROUND

The assessment of myocardial viability has been used to identify patients with coronary artery disease and left ventricular dysfunction in whom coronary-artery bypass grafting (CABG) will provide a survival benefit. However, the efficacy of this approach is uncertain.

METHODS

In a substudy of patients with coronary artery disease and left ventricular dysfunction who were enrolled in a randomized trial of medical therapy with or without CABG, we used single-photon-emission computed tomography (SPECT), dobutamine echocardiography, or both to assess myocardial viability on the basis of prespecified thresholds.

RESULTS

Among the 1212 patients enrolled in the randomized trial, 601 underwent assessment of myocardial viability. Of these patients, we randomly assigned 298 to receive medical therapy plus CABG and 303 to receive medical therapy alone. A total of 178 of 487 patients with viable myocardium (37%) and 58 of 114 patients without viable myocardium (51%) died (hazard ratio for death among patients with viable myocardium, 0.64; 95% confidence interval [CI], 0.48 to 0.86; P=0.003). However, after adjustment for other baseline variables, this association with mortality was not significant (P=0.21). There was no significant interaction between viability status and treatment assignment with respect to mortality (P=0.53).

CONCLUSIONS

The presence of viable myocardium was associated with a greater likelihood of survival in patients with coronary artery disease and left ventricular dysfunction, but this relationship was not significant after adjustment for other baseline variables. The assessment of myocardial viability did not identify patients with a differential survival benefit from CABG, as compared with medical therapy alone. (Funded by the National Heart, Lung, and Blood Institute; STICH ClinicalTrials.gov number, NCT00023595.).

Myocardial reverse remodeling

Despite an extensive literature defining the mechanisms and significance of pathological myocardial remodeling, there has been no comprehensive review of the inverse process, often labeled reverse remodeling. Accordingly, the goal of this review is to overview the varied settings in which clinically significant reverse remodeling has been well documented. When available, we reviewed relevant randomized, controlled clinical trials, and meta-analyses with sufficient cardiac imaging data to permit conclusions about reverse remodeling. When these types of studies were not available, relevant case-control studies and case series that employed appropriate methodology were reviewed. Regression of pathological myocardial hypertrophy, chamber shape distortions, and dysfunction occurs in a wide variety of settings. Although reverse remodeling occurs spontaneously in some etiologies of myocardial dysfunction and failure, remodeling is more commonly observed in response to medical, device-based, or surgical therapies, including β-blockers, revascularization, cardiac resynchronization therapy, and valve surgery. Indeed, reverse remodeling following pathophysiologically targeted interventions helps validate that the targeted mechanisms are propelling and/or sustaining pathological remodeling. The diverse clinical settings in which reverse remodeling has been observed demonstrates that myocardial remodeling is bidirectional and occurs across the full spectrum of myocardial disease severity, duration, and etiology. Observations in several settings suggest that recovered hearts are not truly normal despite parallel improvements at organ, tissue, and cellular level. Nevertheless, the link between reverse remodeling and improved outcomes should inspire further research to better understand the mechanisms responsible for both reverse remodeling and persistent deviations from normalcy.

Quantity of viable myocardium required to improve survival with revascularization in patients with ischemic cardiomyopathy: A meta-analysis

BACKGROUND

This meta-analysis was conducted to determine optimal cutoff values for the assessment of viability using various imaging techniques for which revascularization would offer a survival benefit in patients with ischemic cardiomyopathy (ICM).

METHODS AND RESULTS

We searched five electronic databases to identify relevant studies through December 2008. Relative risks of cardiac death, both in patients with and without viability, were calculated in each study. In order to estimate the optimal threshold for the presence of viability, we assumed a linear relationship between the amount of viable myocardium and survival benefit of revascularization. Twenty-nine studies (4,167 patients) met the inclusion criteria. The optimal threshold for the presence of viability was estimated to be 25.8% (95% CI: 16.6-35.0%) by positron emission tomography using 18F-fluorodeoxyglucose-perfusion mismatch, 35.9% (95% CI: 31.6-40.3%) by stress echocardiography using contractile reserve or ischemic responses, and 38.7% (95% CI: 27.7-49.7%) by single photon emission computed tomography using thallium-201 or technetium-99m MIBI myocardial perfusion.

CONCLUSIONS

The calculated amount of viable myocardium determined to lead to improved survival was different among imaging techniques. Thus, separate cutoff values for imaging modalities may be helpful in determining which patients with ICM benefit from revascularization.

Effect of revascularization on long-term survival in patients with ischemic left ventricular dysfunction and a wide range of viability

Short-term survival in patients with viability and ischemic left ventricular dysfunction appears improved by revascularization, but no randomized studies have shown a long-term benefit of revascularization in patients with a wide range of viability. Propensity analysis was used as a substitute for randomization in a study comparing the survival of revascularized and medically treated patients with ischemic dysfunction. Dobutamine echocardiography was performed in 274 patients with ischemic left ventricular dysfunction (mean ejection fraction 32%), with 32% having viability in > or =25% of the myocardium. Clinical, angiographic, and echocardiographic characteristics were comparable between treatment groups except for multivessel disease, hyperlipidemia, and the percentage of nonviable myocardium. A propensity score, reflecting the probability of receiving revascularization, was derived for each patient from baseline variables. After stratification by propensity scores, there were no differences between groups. Patients were followed for cardiac death. Revascularization was performed in 130 patients, and 144 were medically treated. There were 114 cardiac deaths (42%) over 4.5 years of follow-up. After propensity score adjustment, survival was better with revascularization (mean survival 5.9 vs 3.3 years, hazard ratio 0.42, 95% confidence interval 027 to 0.65, p <0.0001). Medical and device therapy during follow-up was similar between treatment groups, except that beta-blocker use was more common in revascularized patients. After adjustment for beta-blocker use and propensity score, survival remained better in revascularized patients (hazard ratio 0.47, 95% confidence interval 0.30 to 0.72, p = 0.0006). In conclusion, revascularization improves long-term survival in patients with ischemic left ventricular dysfunction and a wide range of viability.

Relationship between myocardial viability and coronary run-off in jeopardized myocardium

OBJECTIVE

The aim of this study was to evaluate the relationship between coronary run-off and myocardial viability in jeopardized regions.

METHOD

We studied 50 patients (40 male, mean age: 55.63 +/- 10.54 years) with coronary artery stenosis >70% and ejection fraction <40% referred for viability study via dobutamine stress echocardiography. The relationship between coronary run-off and viability was evaluated. Good run-off demonstrates good or moderate and no run-off means poor or no run-off.

RESULTS

In the apical region, 33% of the segments with good antegrade run-off were viable and 67% nonviable. Also, 72% of the segments with no run-off were nonviable and 28% viable. In the midportion region, 70% of the segments with good antegrade run-off were viable and 30% nonviable; 50% of the segments with no run-off were nonviable and 50% viable. In the basal region, 85% of the segments with good antegrade run-off were viable and 15% nonviable; 19% of the segments with no run-off were nonviable and 81% viable. The proportion of the nonviable segments increased significantly from the basal to apical regions either with good (p < 0.001) or no run-off (p = 0.004). From 239 viable segments, 58.6% had antegrade, 15.4% retrograde, and 25.5% no run-off. Of 181 nonviable segments, 44% had antegrade, 34% retrograde, and 34.8% no run-off.

CONCLUSION

There was more susceptibility to nonviability in the apical regions despite good run-off, while the basal segments showed more viability in spite of having no run-off. The findings may be helpful for selecting patients with coronary artery disease and left ventricular systolic dysfunction that benefit from revascularization.