Clinical value of exercise Doppler echocardiography in patients with cardiac-valvular disease

Prognostic Utility of Indoxyl Sulfate for Patients with Acute Coronary Syndrome

Aim: We investigated whether indoxyl sulfate (IS), a protein-bound uremic toxin, predicts prognosis after acute coronary syndrome (ACS).

Methods: Serum IS level was determined prospectively in 98 patients who underwent successful primary percutaneous coronary intervention for ACS. Patients on hemodialysis were excluded. The endpoint of this study was six-month composite events including death, nonfatal myocardial infarction, heart failure requiring hospitalization, and adverse bleeding events.

Results: During the mean follow-up period of 168 days, composite events occurred in 13.3% of cases. Serum IS level was significantly higher in subjects who developed composite events than in those without events (0.14 ± 0.11 mg/dl vs. 0.06 ± 0.04 mg/dl; p < 0.001). After adjusting for confounding factors, a Cox proportional hazard analysis revealed that the IS level (hazard ratio (HR): 10.6; 95% confidence interval (CI): 1.63–69.3, p = 0.01), hemoglobin level (HR: 0.61; 95% CI: 0.43–0.87; p < 0.01), and left ventricular ejection fraction (LVEF) (HR: 0.95; 95% CI: 0.91–0.99; p = 0.03) were independent predictive factors of composite events. Furthermore, IS level significantly conferred additional value to the combined established risks of LVEF and hemoglobin level for predicting the incidence of composite events (area under the curve: 0.82 vs. 0.88, p = 0.01; net reclassification improvement: 0.67, p = 0.01; and integrated discrimination improvement: 0.15, p < 0.01).

Conclusions: The assessment of serum IS level has prognostic utility for the management of ACS.

Exercise stress echocardiography in patients with valvular heart disease

Stress echocardiography is recommended for the assessment of asymptomatic patients with severe valvular heart disease (VHD) when there is discrepancy between symptoms and resting markers of severity. The aim of this study is to determine the prognostic value of exercise stress echocardiography in patients with common valve lesions. One hundred and fifteen patients with VHD (aortic stenosis (n=28); aortic regurgitation (n=35); mitral regurgitation, (n=26); mitral stenosis (n=26)), and age- and sex-matched controls (n=39) with normal ejection fraction underwent exercise stress echocardiography. The primary endpoint was a composite of death or hospitalization for heart failure. Asymptomatic VHD patients had lower exercise capacity than controls and 37% of patients achieved <85% of their predicted metabolic equivalents (METS). There were three deaths and four hospital admissions, and 24 patients underwent surgery during follow-up. An abnormal stress echocardiogram (METS <5, blood pressure rise <20 mmHg, or pulmonary artery pressure post exercise >60 mmHg) was associated with an increased risk of death or hospital admission (14% vs 1%, P<0.0001). The assessment of contractile reserve did not offer additional predictive value. In conclusion, an abnormal stress echocardiogram is associated with death and hospitalization with heart failure at 2 years. Stress echocardiography should be considered as part of the routine follow-up of all asymptomatic patients with VHD.

[Asymptomatic severe aortic stenosis with preserved left ventricular ejection fraction. Evaluation by exercise test: which results and which decision?]

Aortic stenosis is the most common valvular heart disease in Europe and North America and it is a real public health problem. Its prevalence increases with population aging. Symptomatic patients require surgery (class I, level of evidence B). In asymptomatic patients, a stress test with or without imaging is recommended to unmask the false asymptomatic patients and refine risk stratification of occurrence of major events. This support remains difficult and makes the optimal timing for surgery controversial in the absence of prospective data on the determinants of aortic stenosis progression, multicenter studies on risk stratification or randomized studies on patient management. The complexity of care arises from the balance between the spontaneous disease risk (risk of sudden death and irreversible left ventricular dysfunction) and the risk of surgery and prosthetic complications. It is therefore crucial to identify subgroups of patients at risk of pejorative progression in whom prophylactic surgery may be considered. This article focuses on evaluating during exercise asymptomatic patients with severe aortic stenosis and preserved left ventricular ejection fraction. We will explain how to perform the test, determine which echocardiographic measurements should be obtained, focusing on the diagnostic and prognostic value of these measurements and discuss indications for surgery according to new practice guidelines.

Systolic function reserve using two-dimensional strain imaging in hypertrophic cardiomyopathy: comparison with essential hypertension

BACKGROUND

Although patients with hypertrophic cardiomyopathy (HCM) have normal ejection fractions at rest, the investigators hypothesized that these patients have differentially abnormal systolic function reserves, limiting their exercise capacity compared with patients with hypertension (HTN).

METHODS

Forty patients with HCM (mean age, 39.1 ± 12 years), 20 patients with HTN with LVH, and 33 healthy individuals underwent resting and peak exercise echocardiography using two-dimensional strain imaging. Peak longitudinal systolic strain (εsys) and strain rate were measured in apical views. Circumferential εsys and left ventricular (LV) twist were analyzed from short-axis views. LV systolic dyssynchrony was measured from regional longitudinal strain curves as the standard deviation of time to peak strain (time from the beginning of the Q wave on electrocardiography to peak εsys) between 12 segments. The differences between resting and peak exercise values were analyzed, and functional reserve was calculated as the difference divided by the resting value.

RESULTS

In patients with HCM, resting values for longitudinal εsys, systolic strain rate, early diastolic strain rate, and atrial diastolic strain rate were significantly lower, while circumferential εsys and twist were higher, compared with patients with HTN and controls (P < .0001). Functional systolic reserve increased during exercise in controls (17 ± 6%), increased to a lesser extent in patients with HTN (10 ± 16%), and was markedly attenuated in patients with HCM (-23 ± 28%) (P < .001). At peak exercise, even with augmented circumferential εsys and twist in patients with HCM (P < .01) compared with those with HTN, both remained lower than in controls (P < .001). LV dyssynchrony was amplified during exercise in patients with HCM compared with those with HTN (P < .001). Within the entire population, exercise capacity was clearly correlated with systolic functional reserve. However when taken separately, it was mainly related to resting LV dyssynchrony and diastolic function in patients with HCM, whereas it was linked to age and LV wall thickness in those with HTN.

CONCLUSIONS

Patients with HCM have significantly limited systolic function reserve and more dynamic dyssynchrony with exercise compared with those with HTN. Two-dimensional strain imaging during stress may provide a new and reliable method to identify patients at higher cardiovascular risk.

[Heart failure with preserved ejection fraction: a systemic disorder?]

When the syndrome of heart failure (HF) is due to left ventricular (LV) systolic dysfunction the clinical manifestations and natural history of the syndrome depend primarily on the severity of LV systolic dysfunction. In contrast, when the syndrome is attributed to LV diastolic dysfunction multiple comorbidities are responsible for the clinical manifestations and the natural history of the syndrome. The present review underscores the multifactorial pathogenesis of the syndrome of HF associated with LV diastolic dysfunction that nowadays is more properly referred to as HF with preserved LV ejection fraction (HFpEF) than to diastolic HF. The prognosis is similarly poor whether HF is due to systolic dysfunction or associated with diastolic dysfunction. The cause of death that is commonly non-cardiovascular in HFpEF supports the pathogenic importance of comorbidities in this condition. Hypertension, chronic kidney disease (CKD), diabetes, obesity and sleep disorder breathing are among the most frequent comorbidities in HFpEF. These comorbidities account for the multiple clinical presentations of the syndrome of HFpEF. Limited functional capacity is in HFpEF largely related to the downward spiral between CKD mediated fluid accumulation and LV stiffness as well as altered ventricular-vascular coupling. The diagnosis of HFpEF currently relies on 2D-Doppler echocardiography findings of impaired LV relaxation and increased LV stiffness and to a lesser extent on biomarkers. Owing to both lack of stringent inclusion and exclusion enrollment criteria and mistaken therapeutic target, placebo-controlled randomized therapeutic trials have been so far negative in HFpEF.

Serum N-terminal brain natriuretic peptide indicates exercise induced augmentation of pulmonary artery pressure in patients with mitral stenosis

INTRODUCTION

To determine whether elevated N-terminal pro-BNP (NT pro-BNP) predicts pulmonary artery systolic pressure increase on exercise stress echocardiography in asymptomatic or mildly symptomatic patients with moderate to severe mitral stenosis.

METHODS AND RESULTS

Forty-one asymptomatic or mildly symptomatic patients with moderate to severe mitral stenosis and 21 age- and sex-matched healthy subjects. Transthoracic echocardiography was performed in all patients to assess the severity of the valve disease and to measure pulmonary artery pressure before and immediately after treadmill exercise. Blood samples for NT pro-BNP were also collected before and immediately after treadmill exercise at the time of echocardiographic examination. The plasma concentrations of NT pro-BNP levels were significantly higher in patients with mitral stenosis than in control subjects before and after exercise (P < 0.001). Patients with atrial fibrillation had significantly higher NT pro-BNP levels compared to those with sinus rhythm (P < 0.001). Pre- and postexercise NT pro-BNP levels correlated statistically significantly with the left atrial (LA) dimension, right ventricle enddiastolic diameter, exercise duration, heart rate, rest, and exercise pulmonary artery systolic pressure, after exercise mitral valve mean gradient. Area under the receiver-operating characteristic curve for NT pro-BNP as an exercise induced augmentation of pulmonary artery pressure was 0.78. Using an optimized cutoff value of 251 pg/mL for NT pro-BNP, sensitivity was 89.47%. The independent determinants of higher pulmonary artery pressure were LA diameter and pretest NT pro-BNP levels in multivariante analysis.

CONCLUSION

NT pro-BNP levels correlate with functional class and echocardiographic findings in patients with mitral stenosis and indicate exercise induced augmentation of peak PAP > 60 mmHg. (Echocardiography 2011;28:8-14).

Key role of Doppler echocardiography in the emergency management of elderly patients

Owing to modern epidemiology in Western countries, ageing represents a growing health burden. In general, because of age itself and comorbid conditions, all clinical cardiovascular manifestations have a higher mortality rate and a worse outcome in older people compared with in younger individuals. Diagnosis of the disease in the elderly in an emergency setting is particularly challenging for the practitioner. Age-related cardiovascular changes and comorbid conditions may alter signs, symptoms and adaptation to the disease and response to treatment. Bedside Doppler echocardiography is likely to play a major role in guiding diagnosis, therapeutic strategies and prognosis. The purpose of this review is to appraise the application of echocardiographic examination in helping the clinician facing emergency situations that involve the cardiovascular system in the older population.