Usefulness of stress echocardiography for risk stratification and prognosis of patients with left ventricular hypertrophy

Exercise stress echocardiography: Where are we now?

Exercise stress echocardiography (ESE) is a widely used diagnostic test in cardiology departments. ESE is mainly used to study patients with coronary artery disease; however, it has increasingly been used in other clinical scenarios including valve pathology, congenital heart disease, hypertrophic and dilated cardiomyopathies, athlete evaluations, diastolic function evaluation, and pulmonary circulation study. In our laboratories, we use an established methodology in which cardiac function is evaluated while exercising on a treadmill. After completing the exercise regimen, patients remain in a standing position or lie down on the left lateral decubitus, depending on the clinical questions to be answered for further evaluation. This method increases the quality and quantity of information obtained. Here, we present the various methods of exercise stress echocardiography and our experience in many clinical arenas in detail. We also present alternatives to ESE that may be used and their advantages and disadvantages. We review recent advances in ESE and future directions for this established method in the study of cardiac patients and underline the advantage of using a diagnostic tool that is radiation-free.

International Study of Comparative Health Effectiveness with Medical and Invasive Approaches (ISCHEMIA) trial: Rationale and design

BACKGROUND

Prior trials comparing a strategy of optimal medical therapy with or without revascularization have not shown that revascularization reduces cardiovascular events in patients with stable ischemic heart disease (SIHD). However, those trials only included participants in whom coronary anatomy was known prior to randomization and did not include sufficient numbers of participants with significant ischemia. It remains unknown whether a routine invasive approach offers incremental value over a conservative approach with catheterization reserved for failure of medical therapy in patients with moderate or severe ischemia.

METHODS

The ISCHEMIA trial is a National Heart, Lung, and Blood Institute supported trial, designed to compare an initial invasive or conservative treatment strategy for managing SIHD patients with moderate or severe ischemia on stress testing. Five thousand one-hundred seventy-nine participants have been randomized. Key exclusion criteria included estimated glomerular filtration rate (eGFR) <30 mL/min, recent myocardial infarction (MI), left ventricular ejection fraction <35%, left main stenosis >50%, or unacceptable angina at baseline. Most enrolled participants with normal renal function first underwent blinded coronary computed tomography angiography (CCTA) to exclude those with left main coronary artery disease (CAD) and without obstructive CAD. All randomized participants receive secondary prevention that includes lifestyle advice and pharmacologic interventions referred to as optimal medical therapy (OMT). Participants randomized to the invasive strategy underwent routine cardiac catheterization followed by revascularization with percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) surgery, when feasible, as selected by the local Heart Team to achieve optimal revascularization. Participants randomized to the conservative strategy undergo cardiac catheterization only for failure of OMT. The primary endpoint is a composite of cardiovascular (CV) death, nonfatal myocardial infarction (MI), hospitalization for unstable angina, hospitalization for heart failure, or resuscitated cardiac arrest. Assuming the primary endpoint will occur in 16% of the conservative group within 4 years, estimated power exceeds 80% to detect an 18.5% reduction in the primary endpoint. Major secondary endpoints include the composite of CV death and nonfatal MI, net clinical benefit (primary and secondary endpoints combined with stroke), angina-related symptoms and disease-specific quality of life, as well as a cost-effectiveness assessment in North American participants. Ancillary studies of patients with advanced chronic kidney disease and those with documented ischemia and non-obstructive coronary artery disease are being conducted concurrently.

CONCLUSIONS

ISCHEMIA will provide new scientific evidence regarding whether an invasive management strategy improves clinical outcomes when added to optimal medical therapy in patients with SIHD and moderate or severe ischemia.

Cardiovascular disease in chronic kidney disease. A clinical update from Kidney Disease: Improving Global Outcomes (KDIGO)

Cardiovascular morbidity and mortality in patients with chronic kidney disease (CKD) is high, and the presence of CKD worsens outcomes of cardiovascular disease (CVD). CKD is associated with specific risk factors. Emerging evidence indicates that the pathology and manifestation of CVD differ in the presence of CKD. During a clinical update conference convened by the Kidney Disease: Improving Global Outcomes (KDIGO), an international group of experts defined the current state of knowledge and the implications for patient care in important topic areas, including coronary artery disease and myocardial infarction, congestive heart failure, cerebrovascular disease, atrial fibrillation, peripheral arterial disease, and sudden cardiac death. Although optimal strategies for prevention, diagnosis, and management of these complications likely should be modified in the presence of CKD, the evidence base for decision making is limited. Trials targeting CVD in patients with CKD have a large potential to improve outcomes.

Influence of left ventricular hypertrophy and geometry on diagnostic accuracy of wall motion and perfusion magnetic resonance during dobutamine stress

BACKGROUND

The purpose of this study was to determine the influence of left ventricular (LV) hypertrophy and geometry on the diagnostic accuracy of wall motion and additional perfusion imaging during high-dose dobutamine/atropine stress magnetic resonance for the detection of coronary artery disease.

METHODS AND RESULTS

Combined dobutamine stress magnetic resonance (DSMR)-wall motion and DSMR-perfusion imaging was performed in a single session in 187 patients scheduled for invasive coronary angiography. Patients were classified into 4 categories on the basis of LV mass (normal, ≤ 81 g/m(2) in men and ≤ 62 g/m(2) in women) and relative wall thickness (RWT) (normal, <0.45) as follows: normal geometry (normal mass, normal RWT), concentric remodeling (normal mass, increased RWT), concentric hypertrophy (increased mass, increased RWT), and eccentric hypertrophy (increased mass, normal RWT). Wall motion and perfusion images were interpreted sequentially, with observers blinded to other data. Significant coronary artery disease was defined as ≥ 70% stenosis. In patients with increased LV concentricity (defined by an RWT ≥ 0.45), sensitivity and accuracy of DSMR-wall motion were significantly reduced (63% and 73%, respectively; P<0.05) compared with patients without increased LV concentricity (90% and 88%, respectively; P<0.05). Although accuracy of DSMR-perfusion was higher than that of DSMR-wall motion in patients with concentric hypertrophy (82% versus 71%; P < 0.05), accuracy of DSMR-wall motion was superior to DSMR-perfusion (90% versus 85%; P < 0.05) in patients with eccentric hypertrophy.

CONCLUSIONS

The accuracy of DSMR-wall motion is influenced by LV geometry. In patients with concentric remodeling and concentric hypertrophy, additional first-pass perfusion imaging during high-dose dobutamine stress improves the diagnostic accuracy for the detection of coronary artery disease.

How to identify the asymptomatic high-risk patient?

Worldwide, cardiovascular diseases are among the leading causes of mortality and morbidity with ever-increasing prevalence. Early targeted initiation of preventive measures would be of great benefit and can provide a major opportunity in reducing mortality and morbidity. To this end, accurate identification of individuals who are still asymptomatic but at elevated risk is essential. However, traditional risk assessment fails to recognize a substantial proportion of patients at high risk while a large proportion of individuals are classified as having intermediate risk, leaving management uncertain. Additional strategies to further refine risk assessment are therefore highly needed. To this end, the use of biomarkers and noninvasive imaging modalities has been proposed. The aim of this review is to provide an overview of the different approaches that are available or under development to improve the identification of asymptomatic individuals at elevated risk for cardiovascular diseases events.

Cardiac assessment in chronic kidney disease

Patients with chronic kidney disease are well recognized to develop a wide range of cardiac structural and functional abnormalities. These changes may be progressive and relate directly to a grossly aggravated risk of cardiovascular events and reduced survival. Although conventional methods of cardiac assessment have been shown to be useful, they are limited by insufficient sensitivity and specificity, to fully appreciate the overall degree of myocardial distress that is common in these patients. This article aims to review the use of established and emerging cardiac imaging tools and, in particular, their application in patients with chronic kidney disease.