Prediction of mortality using dobutamine echocardiography

Evaluation of left ventricular flow field changes after stress in patients with nonobstructive coronary artery disease using ultrasonic flow vector imaging

Purpose

Vector flow mapping and treadmill exercise stress echocardiography were used to evaluate and explore changes in the left ventricular (LV) flow field of patients with nonobstructive coronary artery disease.

Methods

Overall, 34 patients with nonobstructive (<50%) left anterior descending coronary artery stenosis (case group) and 36 patients with no coronary artery stenosis (control group) were included. Apical four-, three-, and two-chamber echocardiographic images were collected at rest and during early recovery from treadmill exercise. LV flow field, vortex area, and circulation (cir) changes were recorded in different phases: isovolumetric systole (S1), rapid ejection (S2), slow ejection (S3), isovolumetric diastole (D1), rapid filling (D2), slow filling (D3), and atrial systole (D4). Intra- and inter-group differences were compared before and after exercise loading.

Results

The control and case groups demonstrated regular trends of eddy current formation and dissipation at rest and under stress. Compared with the control group, the case group had irregular streamline distributions. Abnormal vortices formed in the S1 and D3 apical segments and D1 left ventricular middle segment in the resting group. Compared with the control group, the resting group had decreased left ventricular S1 vortex areas and increased S3 vortex areas. The post-stress D1 and D3 vortex areas and D1 and D2 cir increased. Compared with at rest, after stress, the control group had decreased S1, S3, D2, and D3 vortex areas; increased S2, D1, D3, and D4 cir; and decreased D2 cir. After stress, the case group had decreased S3 and D2 vortex areas, increased D1 vortex areas, and increased S2, D1, D3, and D4 cir (P all < 0.001). Logistic regression and ROC curve analyses show that increased D1 vortex area after stress is an independent risk factor for stenosis in nonobstructive stenosis of coronary arteries (OR: 1.007, 95% CI: 1.005-1.010, P < 0.05). A D1 vortex area cutoff value of 82.26 had an AUC, sensitivity, and specificity of 0.67, 0.655, and 0.726, respectively.

Conclusion

The resting left ventricular flow field changed in patients with nonobstructive left anterior descending coronary artery stenosis. Both groups had more disordered left ventricular blood flow after stress. The increased D1 vortex area after stress is an independent risk factor for mild coronary stenosis and may contribute to the assessment of nonobstructive coronary stenosis. VFM combined with treadmill stress is useful in evaluating left ventricular flow field changes in patients with nonobstructive coronary artery disease, which is valuable in the early evaluation of coronary heart disease.

VEGF-B hypertrophy predisposes to transition from diastolic to systolic heart failure in hypertensive rats

AIMS

Cardiac energy metabolism is centrally involved in heart failure (HF), although the direction of the metabolic alterations is complex and likely dependent on the particular stage of HF progression. Vascular endothelial growth factor B (VEGF-B) has been shown to modulate metabolic processes and to induce physiological cardiac hypertrophy; thus, it could be cardioprotective in the failing myocardium. This study investigates the role of VEGF-B in cardiac proteomic and metabolic adaptation in HF during aldosterone and high-salt hypertensive challenges.

METHODS AND RESULTS

Male rats overexpressing the cardiac-specific VEGF-B transgene (VEGF-B TG) were treated for 3 or 6 weeks with deoxycorticosterone-acetate combined with a high-salt (HS) diet (DOCA + HS) to induce hypertension and cardiac damage. Extensive longitudinal echocardiographic studies of HF progression were conducted, starting at baseline. Sham-treated rats served as controls. To evaluate the metabolic alterations associated with HF, cardiac proteomics by mass spectrometry was performed. Hypertrophic non-treated VEGF-B TG hearts demonstrated high oxygen and adenosine triphosphate (ATP) demand with early onset of diastolic dysfunction. Administration of DOCA + HS to VEGF-B TG rats for 6 weeks amplified the progression from cardiac hypertrophy to HF, with a drastic drop in heart ATP concentration. Dobutamine stress echocardiographic analyses uncovered a significantly impaired systolic reserve. Mechanistically, the hallmark of the failing TG heart was an abnormal energy metabolism with decreased mitochondrial ATP, preceding the attenuated cardiac performance and leading to systolic HF.

CONCLUSIONS

This study shows that the VEGF-B TG accelerates metabolic maladaptation which precedes structural cardiomyopathy in experimental hypertension and ultimately leads to systolic HF.

Evolution of Stress Echocardiogram in the Era of CT Angiography

The ideal diagnostic modality for acute chest pain is a highly debated topic in the cardiovascular community. With the rapid rise of coronary computed tomography angiography (CTA) and the fall of functional testing, stress echocardiography (SE) is at a delicate crossroads. Though there are many advantages of coronary CTA, it is not without its flaws. The exact realm of SE needs to be clearly defined, as well as which patients need diagnostic testing. The emergence of additional parameters will propel the evolution of modern SE. In this review article, we explore the role of SE, guidelines, comparison of SE versus CTA, and additional parameters in the coronary CTA era.

Current Concepts and Future Applications of Non-Invasive Functional and Anatomical Evaluation of Coronary Artery Disease

Over the last decades, significant advances have been achieved in the treatment of coronary artery disease (CAD). Proper non-invasive diagnosis and appropriate management based on functional information and the extension of ischemia or viability remain the cornerstone in the fight against adverse CAD events. Stress echocardiography and single photon emission computed tomography are often used for the evaluation of ischemia. Advancements in non-invasive imaging modalities such as computed tomography (CT) coronary angiography and cardiac magnetic resonance imaging (MRI) have not only allowed non-invasive imaging of coronary artery lumen but also provide additional functional information. Other characteristics regarding the plaque morphology can be further evaluated with the latest modalities achieving a morpho-functional evaluation of CAD. Advances in the utilization of positron emission tomography (PET), as well as software advancements especially regarding cardiac CT, may provide additional prognostic information to a more evidence-based treatment decision. Since the armamentarium on non-invasive imaging modalities has evolved, the knowledge of the capabilities and limitations of each imaging modality should be evaluated in a case-by-case basis to achieve the best diagnosis and treatment decision. In this review article, we present the most recent advances in the noninvasive anatomical and functional evaluation of CAD.

Prognostic Role of Cardiac Power in a Large Cohort of Patients with Normal Ejection Fraction Referred for Dobutamine Stress Echocardiography

BACKGROUND

Cardiac power reflects cardiac performance in terms of energy transferred by the left ventricle (LV) to the aorta per unit time. Peak stress cardiac power has been shown to predict outcome in patients with reduced LV ejection fraction (EF), and more recently, in patients with normal EF referred for exercise stress echocardiography. We sought to evaluate the prognostic significance of cardiac power in patients with normal EF referred for dobutamine stress test (DSE).

METHODS

We studied data from 15,576 patients with EF ≥50% and no significant valvular or right ventricular dysfunction, undergoing DSE. Cardiac power at rest and peak stress and power reserve (peak stress minus rest power) were calculated and normalized to LV mass. Outcome endpoints were all-cause mortality and new-onset heart failure (HF).

RESULTS

The mean age was 66±13 years and 49% patients were females. Resting and peak stress power/mass were 0.7±0.2 and 1.6±0.6 W/100 g of LV myocardium, respectively. During follow-up [median 3.3 (IQR 0.7-7.3) years], 2,278 patients died and 2,137 developed HF. After adjusting for age, sex, comorbidities, and stress test results, lower peak stress power/mass was independently associated with mortality [adjusted hazard ratio (HR), highest vs. lowest quartile, 0.84, 95% confidence intervals (CI) 0.74-0.95, P=0.004] and HF at follow-up [adjusted HR 0.67, 95% CI 0.59-0.76, P<0.0001]. Power reserve showed similar associations with outcomes.

CONCLUSION

Assessment of cardiac power during DSE in patients with normal EF provides valuable prognostic information regarding risk of mortality and future HF, in addition to stress test results. It is an important research tool to study cardiac performance and development of risk scores incorporating this novel index could be considered after further validation in prospective studies.

Revascularization or optimal medical therapy for stable ischemic heart disease: A Bayesian meta-analysis of contemporary trials

BACKGROUND

The role of revascularization in patients with stable ischemic heart disease (SIHD) has been controversial, more so in the present era of drug-eluting stents.

AIMS

To examine the absolute risk difference (ARD) between revascularization plus optimal medical therapy (OMT) versus OMT alone among patients with SIHD using Bayesian approach.

METHODS

PubMed/MEDLINE and Cochrane citation indices were utilized to identify randomized controlled trials (RCTs) through March 31, 2020. Among trials comparing initial revascularization plus OMT with initial OMT alone, revascularization arm must have comprised >50% of patients receiving either percutaneous or surgical revascularization, and >50% of patients must have received aspirin and statin as OMT in both arms.

RESULTS

Seven RCTs (12,494) were included in the final analysis. The ARD of all-cause mortality for revascularization with respect to OMT was centred at -0.002 (95% CrI: -0.01; 0.01, Tau: 0.01, 67% probability of ARD of revascularization vs. OMT < 0). The ARD for cardiac mortality was centred at -0.0025 (95%CrI: -0.01; 0.01, Tau: 0.01, 77% probability of ARD of revascularization vs. OMT < 0). The ARD for MI was -0.02 (95% CrI: -0.06; 0.00, Tau: 0.02, 97% probability of ARD for revascularization vs. OMT < 0). There was 96% probability of ARD for unstable angina with revascularization vs. OMT < 0, 4.5% probability of ARD for freedom from angina with revascularization vs. OMT < 0, and 6% probability of ARD for stroke with revascularization vs. OMT < 0.

CONCLUSIONS

Bayesian analysis demonstrated minimal probability of difference in all-cause mortality and cardiac mortality in patients with SIHD who underwent revascularization compared with OMT alone. However, revascularization was associated with lower probability of MI, unstable angina, and increased freedom from angina, but a higher risk of stroke compared with OMT alone.

PROSPERO

The protocol of this systematic review and meta-analysis was registered in PROSPERO [CRD42020160540].

Updated knowledge and practical implementations of stress echocardiography in ischemic and non-ischemic cardiac diseases: an expert consensus of the Working Group of Echocardiography of the Hellenic Society of Cardiology

Stress echocardiography (SE) is a well-established and valid technique, widely-used for the diagnostic evaluation of patients with ischemic and non-ischemic cardiac diseases. This statement of the Echocardiography Working Group of the Hellenic Society of Cardiology summarizes the consensus of the writing group regarding the applications of SE, based on the expertise of their members and on a critical review of current medical literature. The main objectives of the consensus document include a comprehensive review of SE methodology and training, focusing on the preparation, the protocols used and the analysis of the SE images and an updated, evidence-based knowledge about SE applications on ischemic and non-ischemic heart diseases, such as in cardiomyopathies, heart failure and valvular heart disease.

Controversies in revascularisation for stable coronary artery disease

Recent randomised controlled trials, such as ISCHEMIA and ORBITA, have overturned most of what we were taught in medical school about hospital procedures considered necessary for patients with stable coronary artery disease. In this article, we discuss what these trials mean for physicians and patients considering revascularisation procedures with the hope of reducing the risk of death or alleviating angina.

Death and Myocardial Infarction Following Initial Revascularization Versus Optimal Medical Therapy in Chronic Coronary Syndromes With Myocardial Ischemia: A Systematic Review and Meta-Analysis of Contemporary Randomized Controlled Trials

Background

In chronic coronary syndromes, myocardial ischemia is associated with a greater risk of death and nonfatal myocardial infarction (MI). We sought to compare the effect of initial revascularization with percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) plus optimal medical therapy (OMT) with OMT alone in patients with chronic coronary syndrome and myocardial ischemia on long‐term death and nonfatal MI.

Methods and Results

Ovid Medline, Embase, Scopus, and Cochrane Library databases were searched for randomized controlled trials of PCI or CABG plus OMT versus OMT alone for patients with chronic coronary syndromes. Studies were screened and data were extracted independently by 2 authors. Random‐effects models were used to generate pooled treatment effects. The search yielded 7 randomized controlled trials that randomized 10 797 patients. Median follow‐up was 5 years. Death occurred in 640 of the 5413 patients (11.8%) randomized to revascularization and in 647 of the 5384 patients (12%) randomized to OMT (odds ratio [OR], 0.97; 95% CI, 0.86–1.09; P=0.60). Nonfatal MI was reported in 554 of 5413 patients (10.2%) in the revascularization arms compared with 627 of 5384 patients (11.6%) in the OMT arms (OR, 0.75; 95% CI, 0.57–0.99; P=0.04). In subgroup analysis, nonfatal MI was significantly reduced by CABG (OR, 0.35; 95% CI, 0.21–0.59; P<0.001) but was not reduced by PCI (OR, 0.92; 95% CI, 0.75–1.13; P=0.43) (P‐interaction <0.001).

Conclusions

In patients with chronic coronary syndromes and myocardial ischemia, initial revascularization with PCI or CABG plus OMT did not reduce long‐term mortality compared with OMT alone. CABG plus OMT reduced nonfatal MI compared with OMT alone, whereas PCI did not.

Added Value of CT Attenuation Correction and Prone Positioning in Improving Breast and Subdiaphragmatic Attenuation in Myocardial Perfusion Imaging

Soft-tissue attenuation of γ-photons is the most common source of artifacts and remains an intricate problem for myocardial perfusion imaging (MPI) by SPECT. Breast and subdiaphragmatic artifacts are the most frequent cause of false-positive findings in women. Many methods of overcoming attenuation artifacts have been introduced, including prone positioning to avoid breast attenuation or use of hybrid SPECT/CT systems. The purpose of this study was to evaluate the role of prone images in attenuation correction (AC) when CT AC is compared with MPI. Methods: Forty-four patients were initially included in the study. Statistical analysis was done for 30 patients with suspected or confirmed ischemic heart disease. All patients underwent ordinary supine stress/rest SPECT MPI followed by additional stress/rest prone SPECT and stress/rest SPECT/CT. Each study was interpreted separately, and their results were compared. Results: It was found that 58% (31/53) of the depicted defects were attributable to attenuation artifacts; the CT AC imaging technique was able to correct 52%, versus 49% for prone imaging. Sensitivity, specificity, and diagnostic accuracy were 100%, 90.3%, and 94%, respectively, for CT AC, versus 100%, 83.8%, and 91%, respectively, for prone imaging. Inferior wall defects were more common in men (95%), in whom CT AC performed better than prone imaging (i.e., 92.9% in CT AC vs. 90.9% in prone imaging). On the other hand, anterior wall defects were more common in women (83.3%), in whom prone imaging was better than CT AC. Conclusion: Both CT AC and prone imaging increased the specificity and diagnostic accuracy of MPI without affecting the sensitivity.

Accuracy and Prognostic Value of Physiologist-Led Stress Echocardiography for Coronary Disease

BACKGROUND

We demonstrated that physiologist-led stress echocardiography (PLSE) is feasible for coronary artery disease (CAD) assessment. We sought to extend our work by assessing its accuracy and prognostic value.

METHODS

Retrospective study of 898 subjects undergoing PLSE (n=393) or cardiologist-led stress echocardiography (CLSE) (n=505) for CAD assessment using exercise or dobutamine. For accuracy assessment, the primary outcome was the ability of stress echocardiography to identify significant CAD on invasive coronary angiography (ICA). Incidence of 24-month non-fatal MI, total and cardiac mortality, revascularisation and combined major adverse cardiac events (MACE) were assessed.

RESULTS

Demographics, comorbidities, CAD predictors, CAD pre-test probability and cardiac medications were matched between the PLSE and CLSE groups. PLSE had high sensitivity, specificity, positive and negative predictive value and accuracy (85%, 74%, 69%, 88%, 78% respectively). PLSE accuracy measures were similar and non-inferior to CLSE. There was a similar incidence of individual and combined outcomes in PLSE and CLSE subjects. Negative stress echocardiography conferred a comparably low incidence of non-fatal MI (PLSE 1.4% vs. CLSE 0.9%, p=0.464), cardiac mortality (0.6% vs. 0.0%, p=0.277) and MACE (6.8% vs. 3.1%, p=0.404).

CONCLUSION

This is the first study of the accuracy compared with gold standard of ICA, and prognostic value of PLSE CAD assessment. PLSE demonstrates high and non-inferior accuracy compared with CLSE for CAD assessment. Negative PLSE and CLSE confer a similarly very low incidence of cardiac outcomes, confirming for the first time the important prognostic value of PLSE.

Long-Term Prognostic Value of Coronary Atherosclerotic Plaque Characteristics Assessed by Computerized Tomographic Angiography

We aimed to present the long-term prognostic role of coronary computed tomography angiography (CTA) in a cohort of patients with coronary artery disease (CAD) and noncritical stenosis. A total of 1138 patients who underwent coronary CTA for suspected CAD were included in the study. For the categorization of the coronary atherosclerotic plaque (CAP), the coronary system was divided into 16 segments. For each segment, CAPs were categorized as calcified, noncalcified, and mixed. All-cause and cardiovascular (CV) mortality data were collected for prognostic evaluation. Coronary CTA analyses showed that 34.5% of patients had noncalcified CAP, 14.5% of patients had calcified CAP, and 11% of patients had mixed CAP. During a median of 141.5 months follow-up, CV and all-cause mortality was observed in 57 (5%) and 149 (13.1%) patients, respectively. In multivariable Cox regression analysis, calcified CAP morphology and the extent of involved segments were significant predictors of both CV and all-cause mortality. The presence of calcified CAP morphology and the higher number of diseased coronary segments via coronary CTA might help stratify patients at risk for adverse CV outcomes during long-term follow-up. Patients with these features at index coronary CTA may be evaluated more closely with aggressive preventive measures.

Myocardial Perfusion Imaging Using Positron Emission Tomography

Coronary artery disease (CAD), also known as ischemic heart disease, is a major cause of morbidity and mortality worldwide, and timely noninvasive diagnosis of clinical and subclinical CAD is imperative to mitigate its burden on individual patients and populations. Positron emission tomography (PET) is a versatile tool that can perform relative myocardial perfusion imaging (MPI) with high accuracy; furthermore, it provides valuable information about the coronary microvasculature using rest and stress myocardial blood flow (MBF) and coronary flow reserve (CFR) measurements. Several radiotracers are approved by the US Food and Drug Administration to help with MPI, MBF, and CFR evaluation. A large body of evidence indicates that evaluation of the coronary microcirculation using MBF and CFR provides strong diagnostic and prognostic data in a multitude of patient populations. This review describes the technical aspects of PET compared to other modalities and discusses its clinical uses for diagnosis and prognosis of coronary arterial epicardial and microcirculatory disease.

Clinical Utility of Stress Echocardiography in Remote Indigenous and Non-Indigenous Populations: A 10-Year Study in Central Australia

BACKGROUND

Remote Central Australia has a large Indigenous population and a significant burden of cardiovascular disease. Stress echocardiography has been previously validated as a useful investigation for long-term prognostication. However, there are no prior studies assessing its utility in remote or Indigenous populations.

METHOD

Consecutive individuals undergoing stress echocardiography in Central Australia between 2007 and 2017 were included. Stress echocardiography was performed and reported via standard protocols. Individuals were followed up for all-cause mortality.

RESULTS

One-thousand and eight patients (1,008) (54% Indigenous Australian) were included. After a mean follow-up of 3.5±2.4 years, 54 (5%) patients were deceased. Overall, 797 (79%) patients had no abnormalities during rest or stress echocardiography, with no difference according to ethnicity (p>0.05). In patients with a normal test, annual mortality averaged 1.3% over 5 years of follow-up, with annual mortality significantly higher in Indigenous compared to non-Indigenous individuals (1.8% vs 0.6% respectively). In those with an abnormal test, annual mortality was 4.4% vs 1.3% in Indigenous and non-Indigenous individuals respectively. Increasing age, Indigenous ethnicity and cardiometabolic comorbidities were associated with mortality in univariate analyses (p<0.05 for all). In multivariate models, only chronic kidney disease remained predictive of mortality, with other associations (including Indigenous ethnicity) becoming attenuated.

CONCLUSION

This is the first study to report on the use of stress echocardiography in a remote or Indigenous population. A normal stress echocardiogram in remote Indigenous individuals was able to identify a lower risk group of patients in this setting. Although Indigenous individuals with a normal test still had a higher annual rate of mortality compared to non-Indigenous individuals, this association appeared to be mediated by cardiometabolic comorbidities.

Comparison of NICE and ESC proposed strategies on new onset chest pain and the contemporary clinical utility of pretest probability risk score

AIMS

Patients with de novo chest pain are usually investigated non-invasively. The new UK-National Institute for Health and Care Excellence (NICE) guidelines recommend CT coronary angiography (CTCA) for all patients, while European Society of Cardiology (ESC) recommends functional tests. We sought to compare the clinical utility and perform a cost analysis of these recommendations in two UK centres with different primary investigative strategies.

METHODSRESULTS

We compared two groups of patients, group A (n=667) and group B (n=654), with new onset chest pain in two neighbouring National Health Service hospitals, each primarily following either ESC (group A) or NICE (group B) guidance. We assessed the clinical utility of each strategy, including progression to invasive coronary angiography (ICA) and revascularisation. We present a retrospective cost analysis in the context of UK tariff for stress echo (£176), CTCA (£220) and ICA (£1001). Finally, we sought to identify predictors of revascularisation in the whole population.Baseline characteristics in both groups were similar. The progression to ICA was comparable (9.9% vs 12.0%, p=0.377), with similar requirement for revascularisation (4.0% vs 5.0%.; p=0.532). The average cost of investigations per investigated patient was lower in group A (£279.66 vs £325.77), saving £46.11 per patient. The ESC recommended risk score (RS) was found to be the only predictor of revascularisation (OR 1.05, 95% CI 1.04 to 1.06; p<0.001).

CONCLUSION

Both NICE and ESC-proposed strategies led to similar rates of ICA and need for revascularisation in discrete, but similar groups of patients. The SE-first approach had a lower overall cost by £46.11 per patient, and the ESC RS was the only variable correlated to revascularisation.

Current approach to the diagnosis of atherosclerotic coronary artery disease: more questions than answers

Despite its commonality in routine clinical practice, the approach to a diagnosis of atherosclerotic coronary artery disease remains complex and, in part, contentious. The traditional dogma linking ischaemia to hard clinical outcomes has been questioned and reframed over the years; rather than being a predictor of hard clinical outcomes, the degree of ischaemia may simply be a marker of atherosclerotic disease burden. A renewed interest in the imaging of plaque burden has spawned the contemporary role of CT imaging for not only diagnosis and prognosis, but also for dictating downstream management. As the technology develops and evidence expands, decisions on investigative modalities remain centred around patient factors, local availability, test performance and cost. This review summarizes the available methods for diagnosis in the symptomatic patient and provides an overview of the current evidence behind functional and anatomical approaches.

The value of negative stress echocardiography in predicting cardiovascular events among adults with no known coronary disease

Introduction: Stress echocardiography is a safe and cost-effective method of evaluating the patients with suspected coronary artery disease (CAD). However, the risk factors of an adverse cardiovascular event after a normal exercise (ESE) or dobutamine (DSE) stress echocardiography are not well established.

Methods: A cohort of 705 patients without previous history of CAD and a negative ESE/DSE was studied. All studies were performed in a high-volume echocardiologic laboratory and interpreted by two experienced echocardiography-trained cardiologists. Patients with inconclusive studies and those with an evidence of myocardial ischemia were excluded. Demographic, echocardiographic and hemodynamic findings were recorded. Patients were followed for at least 2 years. Independent predictors of major adverse cardiovascular events (MACE) were determined by regression analysis.

Results: During a period of 55.7±17.5 months, MACE occurred in 35 (5.0%) of patients. Negative predictive value (NPV) of DSE was 89.2%, which was significantly less than 96.5% for ESE in predicting the occurrence of MACE (P = 0.001). MACE occurred more frequently among older (≥65 years) men with preexisting diabetes, hypertension, and/or hyperlipidemia. During ESE, a higher maximum blood pressure*heart rate product for the achieved level of metabolic equivalent (METS) of tasks was also an independent predictor of MACE.

Conclusion: Inability of patients to undergo traditional ESE that led to the choice of using DSE alternative reduces the NPV of the stress echocardiography among patients without previous history of CAD. A modest rise of heart rate and blood pressure in response to increased level of activity serves as favorable prognostic value and improves the NPV of stress echocardiography.

[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.

CT coronary angiography: a paradigm shift for functional imaging tests

The UK National Institute for Health and Care Excellence (NICE) have just updated their guideline on new-onset stable chest pain, recommending that all patients should be investigated with a CT coronary angiography (CTCA). In a separate guideline, NICE recommended CT fractional flow reserve (CT-FFR), to assess coronary stenoses, found on CTCA, stating that this would reduce the need for invasive coronary angiography and hence reduce cost. We discuss the evidence base for CT-FFR and emphasise that we already have established functional imaging tests, with extensive evidence base for efficacy and prognosis and that CT-FFR should be compared with this standard of care and not with the much more expensive and invasive fractional flow reserve undertaken during invasive coronary angiography.

Stress Echocardiography Positivity Predicts Cancer Death

BACKGROUND

Stress echocardiography (SE) predicts cardiac death, but an increasing share of cardiac patients eventually die of cancer. The aim of the study was to assess whether SE positivity predicts cancer death.

METHODS AND RESULTS

In a retrospective analysis of prospectively acquired single-center, observational data, we evaluated 4673 consecutive patients who underwent SE from 1983 to 2009. All patients were cancer-free at index SE and were followed up for a median of 131 months (interquartile range 134). We separately analyzed predetermined end points: cardiovascular, cancer, and noncardiovascular, noncancer death, with and without competing risk. SE was positive in 1757 and negative in 2916 patients; 869 cardiovascular, 418 cancer, and 625 noncardiovascular, noncancer deaths were registered. The 25-year mortality was higher in SE-positive than in SE-negative patients, considering cardiovascular (40% versus 31%; P<0.001) and cancer mortality (26% versus 17%; P<0.01). SE positivity was a strong predictor of cancer (cause-specific hazard ratio 1.19; 95% confidence interval, 1.16-1.73; P=0.05) and cardiovascular mortality (1.18; 95% confidence interval, 1.03-1.35; P=0.02). Fine-Gray analysis to account for competing risk gave similar results. Cancer risk diverged after 15 years, whereas differences were already significant at 5 years for cardiovascular risk.

CONCLUSIONS

SE results predict cardiovascular and cancer mortality. SE may act as a proxy of the shared risk factor milieu for cancer or cardiovascular death.

Baseline mitral regurgitation predicts outcome in patients referred for dobutamine stress echocardiography

A number of parameters recorded during dobutamine stress echocardiography (DSE) are associated with worse outcome. However, the relative importance of baseline mitral regurgitation (MR) is unknown. The aim of this study was to assess the prevalence and associated implications of functional MR with long-term mortality in a large cohort of patients referred for DSE. 6745 patients (mean age 64.9 ± 12.2 years) were studied. Demographic, baseline and peak DSE data were collected. All-cause mortality was retrospectively analyzed. DSE was successfully completed in all patients with no adverse outcomes. MR was present in 1019 (15.1%) patients. During a mean follow up of 5.1 ± 1.8 years, 1642 (24.3%) patients died and MR was significantly associated with increased all-cause mortality (p < 0.001). With Kaplan-Meier analysis, survival was significantly worse for patients with moderate and severe MR (p < 0.001). With multivariate Cox regression analysis, moderate and severe MR (HR 2.78; 95% CI 2.17-3.57 and HR 3.62; 95% CI 2.89-4.53, respectively) were independently associated with all-cause mortality. The addition of MR to C statistic models significantly improved discrimination. MR is associated with all-cause mortality and adds incremental prognostic information among patients referred for DSE. The presence of MR should be taken into account when evaluating the prognostic significance of DSE results.

Stress Echocardiography in Stable Coronary Artery Disease

PURPOSE OF REVIEW

Stress echocardiography (SE) is a well-established technique for the diagnosis and risk stratification of patients with known or suspected coronary artery disease (CAD). This review article summarizes the status of SE in CAD, including testing protocols, clinical efficacy and current use of newer technologies: myocardial perfusion, strain imaging, three-dimensional echocardiography and adjunctive carotid ultrasonography.

RECENT FINDINGS

Recent major findings in SE include the clinical value of myocardial perfusion imaging in multicentre studies, as well as when added to left ventricular (LV) wall motion assessment in clinical service. Additionally, SE has been shown to be more cost-effective than exercise ECG in patients with low-intermediate pre-test probability of CAD. Adjunctive atherosclerosis imaging by carotid ultrasonography (CU) to ischaemia testing by SE provides synergistic prognostic value, equivalent to hybrid imaging by PET-CT. Despite the development of newer and more expensive imaging modalities, SE remains the cornerstone for the assessment of CAD and has excellent clinical efficacy, is safe and is cost-effective.

Prognostic Value of Noninvasive Cardiovascular Testing in Patients With Stable Chest Pain: Insights From the PROMISE Trial (Prospective Multicenter Imaging Study for Evaluation of Chest Pain)

BACKGROUND

Optimal management of patients with stable chest pain relies on the prognostic information provided by noninvasive cardiovascular testing, but there are limited data from randomized trials comparing anatomic with functional testing.

METHODS

In the PROMISE trial (Prospective Multicenter Imaging Study for Evaluation of Chest Pain), patients with stable chest pain and intermediate pretest probability for obstructive coronary artery disease (CAD) were randomly assigned to functional testing (exercise electrocardiography, nuclear stress, or stress echocardiography) or coronary computed tomography angiography (CTA). Site-based diagnostic test reports were classified as normal or mildly, moderately, or severely abnormal. The primary end point was death, myocardial infarction, or unstable angina hospitalizations over a median follow-up of 26.1 months.

RESULTS

Both the prevalence of normal test results and incidence rate of events in these patients were significantly lower among 4500 patients randomly assigned to CTA in comparison with 4602 patients randomly assigned to functional testing (33.4% versus 78.0%, and 0.9% versus 2.1%, respectively; both P<0.001). In CTA, 54.0% of events (n=74/137) occurred in patients with nonobstructive CAD (1%-69% stenosis). Prevalence of obstructive CAD and myocardial ischemia was low (11.9% versus 12.7%, respectively), with both findings having similar prognostic value (hazard ratio, 3.74; 95% confidence interval [CI], 2.60-5.39; and 3.47; 95% CI, 2.42-4.99). When test findings were stratified as mildly, moderately, or severely abnormal, hazard ratios for events in comparison with normal tests increased proportionally for CTA (2.94, 7.67, 10.13; all P<0.001) but not for corresponding functional testing categories (0.94 [P=0.87], 2.65 [P=0.001], 3.88 [P<0.001]). The discriminatory ability of CTA in predicting events was significantly better than functional testing (c-index, 0.72; 95% CI, 0.68-0.76 versus 0.64; 95% CI, 0.59-0.69; P=0.04). If 2714 patients with at least an intermediate Framingham Risk Score (>10%) who had a normal functional test were reclassified as being mildly abnormal, the discriminatory capacity improved to 0.69 (95% CI, 0.64-0.74).

CONCLUSIONS

Coronary CTA, by identifying patients at risk because of nonobstructive CAD, provides better prognostic information than functional testing in contemporary patients who have stable chest pain with a low burden of obstructive CAD, myocardial ischemia, and events.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01174550.

Effect of Coronary Revascularization on the Prognostic Value of Stress Myocardial Contrast Wall Motion and Perfusion Imaging

Background

The assessment of myocardial perfusion (MP) and wall motion (WM) using contrast dipyridamole echocardiography (cSE‐WMP) improves the sensitivity to detect coronary artery disease and the stratification of cardiac events, but its long‐term value for fatal and nonfatal ischemic cardiac events, also with respect to patients undergoing revascularization or not, remains to be determined.

Methods and Results

One‐thousand three‐hundred and twenty‐nine patients with suspect or known CAD who underwent cSE‐WMP were followed for a median 5.5 years. The independent prognostic value of cSE‐WMP regarding cardiac death or nonfatal myocardial infarction was related to stress WM and MP, rest ejection fraction, clinical risk factors, and medications. Patients revascularized after cSE‐WMP were separately analyzed to determine whether the procedure influenced outcome and whether this depends on cSE‐WMP results. A total of 125 cardiac fatal and nonfatal ischemic events (9.4%) occurred during the follow‐up (61 deaths, 64 myocardial infarctions). The 5‐year event rate with normal MP and WM was 5.9%, 9.9% with isolated MP defects (normal WM), and 15.5% with both MP and WM abnormalities. In patients not undergoing revascularization (n=1111), reversible MP defects added discrimination value over WM response and clinical factors/medication data (P=0.001), while in the cohort undergoing revascularization (n=218), cSE‐WMP results did not influence outcome.

Conclusions

cSE‐WMP, with both contrast MP and WM assessments, provides independent, incremental prognostic information regarding ischemic cardiac events at 5 years in patients with known or suspected coronary artery disease. Revascularization reduces cardiac events after an abnormal cSE‐WMP, resulting in outcomes not different from those in patients with normal cSE‐WMP.

Long-term prognostic performance of low-dose coronary computed tomography angiography with prospective electrocardiogram triggering

OBJECTIVES

To assess long-term prognosis after low-dose 64-slice coronary computed tomography angiography (CCTA) using prospective electrocardiogram-triggering.

METHODS

We included 434 consecutive patients with suspected or known coronary artery disease referred for low-dose CCTA. Patients were classified as normal, with non-obstructive or obstructive lesions, or previously revascularized. Coronary artery calcium score (CACS) was assessed in 223 patients. Follow-up was obtained regarding major adverse cardiac events (MACE): cardiac death, myocardial infarction and elective revascularization. We performed Kaplan-Meier analysis and Cox regressions.

RESULTS

Mean effective radiation dose was 1.7 ± 0.6 mSv. At baseline, 38% of patients had normal arteries, 21% non-obstructive lesions, 32% obstructive stenosis and 8% were revascularized. Twenty-nine patients (7%) were lost to follow-up. After a median follow-up of 6.1 ± 0.6 years, MACE occurred in 0% of patients with normal arteries, 6% with non-obstructive lesions, 30% with obstructive stenosis and 39% of those revascularized. MACE occurrence increased with increasing CACS (P < 0.001), but 4% of patients with CACS = 0 experienced MACE. Multivariate Cox regression identified obstructive stenosis, lesion burden in CCTA and CACS as independent MACE predictors (P ≤ 0.001).

CONCLUSION

Low-dose CCTA with prospective electrocardiogram-triggering has an excellent long-term prognostic performance with a warranty period >6 years for patients with normal coronary arteries.

KEY POINTS

• Coronary CT angiography (CCTA) has an excellent long-term prognostic performance. • CCTA can accurately stratify cardiac risk according to coronary lesion severity. • A normal CCTA predicts freedom from cardiac events for >6 years. • Patients with a coronary calcium score of 0 may experience cardiac events. • CCTA allows for reclassification of cardiac risk compared with ESC SCORE.

Cardiac Imaging in the Diagnosis of Coronary Artery Disease

Coronary artery disease (CAD) continues to be a leading cause of morbidity and mortality worldwide. Although invasive coronary angiography has previously been the gold standard in establishing the diagnosis of CAD, there is a growing shift to more appropriately use the cardiac catheterization laboratory to perform interventional procedures once a diagnosis of CAD has been established by noninvasive imaging modalities rather than using it primarily as a diagnostic facility to confirm or refute CAD. With ongoing technological advancements, noninvasive imaging plays a pre-eminent role in not only diagnosing CAD but also informing the choice of appropriate therapies, establishing prognosis, all while containing costs and providing value-based care. Multiple imaging modalities are available to evaluate patients suspected of having coronary ischemia, such as stress electrocardiography, stress echocardiography, single-photon emission computed tomography myocardial perfusion imaging, positron emission tomography, coronary computed tomography (CT) angiography, and magnetic resonance imaging. These imaging modalities can variably provide functional and anatomical delineation of coronary stenoses and help guide appropriate therapy. This review will discuss their advantages and limitations and their usage in the diagnostic pathway for patients with CAD. We also discuss newer technologies such as CT fractional flow reserve, CT angiography with perfusion, whole-heart coronary magnetic resonance angiography with perfusion, which can provide both anatomical as well as functional information in the same test, thus obviating the need for multiple diagnostic tests to obtain a comprehensive assessment of both, plaque burden and downstream ischemia. Recognizing that clinicians have a multitude of tests to choose from, we provide an underpinning of the principles of ischemia detection by these various modalities, focusing on anatomy vs physiology, the database justifying their use, their prognostic capabilities and lastly, their appropriate and judicious use in this era of patient-centered, cost-effective imaging.

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 dobutamine stress myocardial perfusion echocardiography in patients with known or suspected coronary artery disease and normal left ventricular function

Objective

We sought to determine the prognostic value of qualitative and quantitative analysis obtained by real-time myocardial perfusion echocardiography (RTMPE) in patients with known or suspected coronary artery disease (CAD).

Background

Quantification of myocardial blood flow reserve (MBFR) in patients with CAD using RTMPE has been demonstrated to further improve accuracy over the analysis of wall motion (WM) and qualitative analysis of myocardial perfusion (QMP).

Methods

From March 2003 to December 2008, we prospectively studied 168 patients with normal left ventricular function (LVF) who underwent dobutamine stress RTMPE. The replenishment velocity reserve (β) and MBFR were derived from RTMPE. Acute coronary events were: cardiac death, myocardial infarction and unstable angina with need for urgent coronary revascularization.

Results

During a median follow-up of 34 months (5 days to 6.9 years), 17 acute coronary events occurred. Abnormal β reserve in ≥2 coronary territories was the only independent predictor of events hazard ratio (HR) = 21, 95% CI = 4.5–99; p<0.001). Both, abnormal β reserve and MBFR added significant incremental value in predicting events over qualitative analysis of WM and MP (χ2 = 6.6 and χ2 = 24.6, respectively; p = 0.001 and χ2 = 6.6 and χ2 = 15.5, respectively; p = 0.012, respectively). When coronary angiographic data was added to the multivariate analysis model, β reserve remained the only predictor of events with HR of 21.0 (95% CI = 4.5–99); p<0.001.

Conclusion

Quantitative dobutamine stress RTMPE provides incremental prognostic information over clinical variables, qualitative analysis of WM and MP, and coronary angiography in predicting acute coronary events.

The prognostic role of stress echocardiography in a contemporary population and the clinical significance of limited apical ischaemia

INTRODUCTION

In this study, we aim to reassess the prognostic value of stress echocardiography (SE) in a contemporary population and to evaluate the clinical significance of limited apical ischaemia, which has not been previously studied.

METHODS

We included 880 patients who underwent SE. Follow-up data with regards to MACCE (cardiac death, myocardial infarction, any repeat revascularisation and cerebrovascular accident) were collected over 12 months after the SE. Mortality data were recorded over 27.02 ± 4.6 months (5.5-34.2 months). We sought to investigate the predictors of MACCE and all-cause mortality.

RESULTS

In a multivariable analysis, only the positive result of SE was predictive of MACCE (HR, 3.71; P = 0.012). The positive SE group was divided into 2 subgroups: (a) inducible ischaemia limited to the apical segments ('apical ischaemia') and (b) ischaemia in any other segments with or without apical involvement ('other positive'). The subgroup of patients with apical ischaemia had a significantly worse outcome compared to the patients with a negative SE (HR, 3.68; P = 0.041) but a similar outcome to the 'other positive' subgroup. However, when investigated with invasive coronary angiography, the prevalence of coronary artery disease (CAD) and their rate of revascularisation was considerably lower. Only age (HR, 1.07; P < 0.001) was correlated with all-cause mortality.

CONCLUSION

SE remains a strong predictor of patients' outcome in a contemporary population. A positive SE result was the only predictor of 12-month MACCE. The subgroup of patients with limited apical ischaemia have similar outcome to patients with ischaemia in other segments despite a lower prevalence of CAD and a lower revascularisation rate.

Long-Term (>10 Years) Prognostic Value of Dobutamine Stress Echocardiography in a High-Risk Cohort

The prognostic value of dobutamine stress echocardiography (DSE) at >10-year follow-up is unknown. The aim of this study was to assess the very long-term prognostic value of DSE in a high-risk cohort of patients with known or suspected coronary artery disease. This prospective, single-center study included 3,381 patients who underwent DSE from January 1990 to January 2003. Two-dimensional echocardiographic images were acquired at rest, during dobutamine stress, and during recovery. Follow-up events were collected and included overall mortality, cardiac death, nonfatal myocardial infarction, and revascularization. The incremental value of DSE in the prediction of selected end points was evaluated using multivariate Cox proportional hazard analysis. During a mean follow-up of 13 ± 3.2 years (range 7.3 to 20.5 years), there were 1,725 deaths (51%), of which 1,128 (33%) were attributed to cardiac causes. Patients with an abnormal DSE had a higher mortality rate (44% vs 35% at 15-year follow-up, p <0.001) than those with a normal DSE. When comparing echocardiographic variables at rest to variables at maximum dose dobutamine, the chi-square of the test improved from 842 to 870 (p <0.0001) and from 684 to 740 (p <0.0001) for all-cause mortality and cardiac death, respectively. DSE provided incremental value in predicting all-cause mortality, cardiac death, and hard cardiac events. There seems, however, to be a "warranty period" of approximately 7 years, when the survival curves of a normal and abnormal DSE no longer diverge.

The prognostic value of dobutamine stress echocardiography amongst British Indian Asian and Afro-Caribbean patients: a comparison with European white patients

Background

The incidence of cardiovascular disease is considerably disparate among different racial and ethnic populations. While dobutamine stress echocardiography (DSE) has been shown to be useful in Caucasian patients, its role among ethnic minority groups remains unclear. This study aimed to investigate the prognostic importance of DSE in three ethnic groups in the UK.

Methods

DSE was performed on 6231 consecutive patients. After exclusions, 5329 patients formed the study (2676 [50.2 %] Indian Asian, 2219 [41.6 %] European white and 434 [8.1 %] Afro-Caribbean). Study outcome measures were non-fatal cardiac events (NFCE) and all-cause mortality.

Results

There were 849 (15.9 %) NFCE and 1365 (25.6 %) deaths over a median follow-up period of 4.6 years. In total 1174 (22 %) patients had inducible myocardial ischaemia during DSE, 859 (16.1 %) had fixed wall motion abnormalities and 3645 (68.4 %) patients had a normal study. Ethnicity did not predict events. Among the three ethnic groups, ischaemia on DSE was associated with 2 to 2.5 times the risk of non-fatal cardiac events and 1.2 to 1.4 times the risk of all-cause mortality. Peak wall motion score index was the strongest independent predictor of non-fatal cardiac events and all-cause mortality in all groups. The C statistic for the prediction of NFCE and all-cause mortality were significantly higher when DSE parameters were added to the standard risk factors for all ethnic groups.

Conclusions

DSE is a strong predictor of NFCE and all-cause mortality and provides predictive information beyond that provided by standard risk factors in three major racial and ethnic groups. No major differences among racial and ethnic groups in the predictive value of DSE was detected.

Electronic supplementary material

The online version of this article (doi:10.1186/s12947-015-0028-1) contains supplementary material, which is available to authorized users.

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.

Role of coronary physiology in the contemporary management of coronary artery disease

Coronary artery disease (CAD) remains the leading cause of death worldwide with approximately 1 in 30 patients with stable CAD experiencing death or acute myocardial infarction each year. The presence and extent of resultant myocardial ischaemia has been shown to confer an increased risk of adverse outcomes. Whilst, optimal medical therapy (OMT) forms the cornerstone of the management of patients with stable CAD, a significant number of patients present with ischaemia refractory to OMT. Historically coronary angiography alone has been used to determine coronary lesion severity in both stable and acute settings. It is increasingly clear that this approach fails to accurately identify the haemodynamic significance of lesions; especially those that are visually “intermediate” in severity. Revascularisation based upon angiographic appearances alone may not reduce coronary events above OMT. Technological advances have enabled the measurement of physiological indices including the fractional flow reserve, the index of microcirculatory resistance and the coronary flow reserve. The integration of these parameters into the routine management of patients presenting to the cardiac catheterization laboratory with CAD represents a critical adjunctive tool in the optimal management of these patients by identifying patients that would most benefit from revascularisation and importantly also highlighting patients that would not gain benefit and therefore reducing the likelihood of adverse outcomes associated with coronary revascularisation. Furthermore, these techniques are applicable to a broad range of patients including those with left main stem disease, proximal coronary disease, diabetes mellitus, previous percutaneous coronary intervention and with previous coronary artery bypass grafting. This review will discuss current concepts relevant to coronary physiology assessment, its role in the management of both stable and acute patients and future applications.

Stress echocardiography

Stress echocardiography is the combination of 2D echocardiography with a physical, pharmacological or electrical stress. The diagnostic end point for the detection of myocardial ischemia is the induction of a transient worsening in regional function during stress. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging but at a substantially lower cost, without environmental impact and with no biohazards for the patient and the physician. In spite of its dependence upon operator's training, it is the best possible choice to achieve the still elusive target of sustainable cardiac imaging in the field of noninvasive diagnosis of coronary artery disease.

Stress cardiac MR imaging compared with stress echocardiography in the early evaluation of patients who present to the emergency department with intermediate-risk chest pain

PURPOSE

To compare the utility and efficacy of stress cardiac magnetic resonance (MR) imaging and stress echocardiography in an emergency setting in patients with acute chest pain (CP) and intermediate risk of coronary artery disease (CAD).

MATERIALS AND METHODS

Written informed consent was obtained from all patients. This HIPAA-compliant study was approved by the institutional review board for research ethics. Sixty patients without history of CAD presented to the emergency department with intermediate-risk acute CP and were prospectively enrolled. Patients underwent both stress cardiac MR imaging and stress echocardiography in random order within 12 hours of presentation. Stress imaging results were interpreted clinically immediately (blinded interpretation was performed months later), and coronary angiography was performed if either result was abnormal. CAD was considered significant if it was identified at angiography (narrowing >50% ) or if a cardiac event (death or myocardial infarction) occurred during follow-up (mean, 14 months ± 5 [standard deviation]). McNemar test was used to compare the diagnostic accuracy of techniques.

RESULTS

Stress cardiac MR imaging and stress echocardiography had similar specificity, accuracy, and positive and negative predictive values (92% vs 96%, 93% vs 88%, 67% vs 60%, and 100% vs 91%, respectively, for clinical interpretation; 90% vs 92%, 90% vs 88%, 58% vs 56%, and 98% vs 94%, respectively, for blinded interpretation). Stress cardiac MR imaging had higher sensitivity at clinical interpretation (100% vs 38%, P = .025), which did not reach significance at blinded interpretation (88% vs 63%, P = .31). However, multivariable logistic regression analysis showed stress cardiac MR imaging to be the strongest independent predictor of significant CAD (P = .002).

CONCLUSION

In patients presenting to the emergency department with intermediate-risk CP, adenosine stress cardiac MR imaging performed within 12 hours of presentation is safe and potentially has improved performance characteristics compared with stress echocardiography. Online supplemental material is available for this article.

Prognostic value of treadmill stress echocardiography at extremes of exercise performance: submaximal <85% maximum predicted heart rate versus high exercise capacity ≥ 10 metabolic equivalents

BACKGROUND

Submaximal stress testing or achieving <85% maximum predicted heart rate (MPHR) may lead to nondiagnostic results and indeterminate outcomes. High exercise capacity (≥ 10 metabolic equivalents, METS) is a predictor of favorable prognosis. The purpose of this study was to evaluate the prognostic value of submaximal or high exercise capacity stress echocardiography.

METHODS

We evaluated 1781 patients (55 ± 13 years; 59% male) undergoing treadmill stress echocardiography divided into 811 patients with submaximal (<85% MPHR) and 970 patients with high exercise capacity (≥ 10 METS). Resting left ventricular ejection fraction and regional wall motion were assessed. The left ventricle was divided into 16 segments and scored on 5-point scale of wall motion. Abnormal stress echocardiography was defined as stress-induced ischemia (wall-motion score of ≥ 1 grade). Follow-up (3.3 ± 1.5 years) for nonfatal myocardial infarction (MI) (n = 40) and cardiac death (n = 52) were obtained.

RESULTS

By univariate analysis, echocardiographic variables of ejection fraction, peak wall-motion score index (WMSI) and number of new ischemic wall-motion abnormalities were significant predictors of cardiac events. Cumulative survival was significantly worse in patients with abnormal (ischemic) versus normal (nonischemic) stress echocardiography in submaximal (4.4%/year vs. 1.3%/year, P < 0.0001) and high exercise capacity (1.5%/year vs. 0.2%/year, P < 0.0001) studies. Multivariate Cox proportional hazards analysis identified number of new ischemic wall-motion abnormalities as the strongest predictor of cardiac events (P < 0.05) in both groups.

CONCLUSIONS

Despite normal stress echocardiography, the inability to achieve 85% MPHR conferred a higher, intermediate cardiac event rate of 2.9%/year. The ability to achieve 9 minutes (≥ 10 metabolic equivalents, METS) conferred an overall low cardiac event rate of 0.4%/year. However, the absence or presence of ischemia by stress echocardiography was able to further risk stratify patients with either submaximal or high exercise capacity studies.

The Prognostic Significance of Resting Regional Left Ventricular Function in Patients With Varying Degrees of Myocardial Ischemia

Background

Our aim was to determine whether regional left ventricular (LV) function on a resting transthoracic echo (TTE) provides prognostic information in patients with varying degrees of ischemia on myocardial perfusion imaging.

Methods

Between 2004 - 2009, we identified 503 patients (mean age 69 (SD 11); 79% male) with reversible ischemia on a myocardial SPECT scan who had a TTE within 30 days. We evaluated the rate of subsequent revascularization and death for all patients.

Results

Following the SPECT scan and TTE, 246/503(49%) patients underwent revascularization, 64/503 (13%) patients died, 369 (73%) patients had a normal left ventricular ejection fraction (LVEF), 242 (48%) patients had a resting wall motion abnormality (WMA), 21/261 (8%) with no WMA died compared to 43/242 (18%) in patients with a WMA. In patients with a WMA (n = 242) there was no significant difference in mortality when comparing patients with small (< 6 segments) and large (> 6 segments) WMA (P = 0.44). In patients with moderate/severe ischemia, the presence of a resting WMA was associated with a higher mortality rate (18% v 7%; P = 0.005). In a multivariable model, LVEF (< 50%) was associated with a hazard ratio of 2.2 (P = 0.002, 95% CI 1.34 - 3.68) however, WMA and number of abnormal segments did not reach statistical significance.

Conclusion

A resting wall motion abnormality in patients with moderate/severe ischemia is associated with a higher mortality compared to patients with mild ischemia on myocardial perfusion imaging. Regional left ventricular dysfunction unlike LVEF was not an independent predictor of mortality.

Prognosis of patients with mild-moderate coronary artery stenosis detected by coronary computed tomography angiography

BACKGROUND

In addition to the diagnostic performance, coronary computed tomography angiography (CTA) can give important data regarding the prognosis of coronary artery disease (CAD). In this study we aimed to evaluate the prognostic role of coronary CTA in patients with suspected CAD and mild-moderate coronary stenosis.

METHODS

A total of 1115 patients (602 male, 54%; age 58.4 ± 11.4) without previous CAD were enrolled. Patients underwent coronary CTA imaging using dual-source 64-slice CT scanner. For categorization of the coronary atherosclerotic plaques (CAP), the coronary system was divided into 16 separate segments. For each segment, CAPs were categorized as: calcified, noncalcified and mixed.

RESULTS

During follow-up of 29.7 ± 13.2 months, cardiovascular events defined as ST segment elevation myocardial infarction (4 patients), non-ST segment elevation myocardial infarction (5 patients) and unstable angina pectoris (20 patients) requiring revascularization or hospital admission were recorded. Cox hazard regression analysis revealed an association between the severity of luminal stenosis (HR: 4.73, 95% CI: 1.36-16.47, p<0.05) and extent (HR: 1.10, 95% CI: 1.00-1.22, p=0.051) and the adverse coronary events in the follow-up. Multivariate Cox hazard regression analysis revealed that nonobstructive (≤ 50%) lesions were the only factor causing increased probability of coronary events in the follow-up (HR: 4.77, 95% CI: 1.36-16.74, p<0.05).

CONCLUSION

The presence and severity of luminal stenosis shown by coronary CTA were associated with prognosis of coronary events in the follow-up. These results may improve the risk stratification in patients evaluated by coronary CTA and provide strategies for the individualized prevention programs.