Clinical indications for intravascular ultrasound imaging.

Intravascular ultrasound (IVUS) is a catheter-based imaging modality, which provides high resolution cross-sectional images of the coronary arteries. Unlike angiography, which displays only the opacified luminal silhouette, IVUS permits imaging of both the lumen and vessel wall and allows characterization of the type of the plaque. Although IVUS provides accurate quantitative and qualitative information regarding the lumen and outer vessel wall, it is not routinely used during coronary angiography or in angioplasty procedures because the risk to benefit ratio (additional expense, procedural time, certain degree of risk, and complication versus improvement in the outcome) does not justify routine utilization. Nevertheless, there are situations where IVUS is extremely useful tool both for diagnosis and management so the aim of this review is to summarize the indications for IVUS imaging in the contemporary clinical practice.

Left ventricular morphology, global and longitudinal function in normal older individuals: a cardiac magnetic resonance study.

BACKGROUND: The heart transforms structurally and functionally with age but the nature and magnitude of reported changes appear inconsistent. This study was designed to assess left ventricular (LV) morphology, global and longitudinal function in healthy older men and women using cardiac magnetic resonance (CMR). METHODS: Ninety-five healthy subjects (age 62+/-16 years, range 22-91 years) underwent breath-hold cine CMR. LV end-diastolic volume (EDV), end-systolic volume (ESV), myocardial mass, ejection fraction (EF), mass-to-volume ratio, mean midventricular wall motion, thickness and thickening were calculated from short-axis data sets. Average mitral annular displacement was measured to assess longitudinal LV function. RESULTS: Subjects were divided according to age (< 65 and > or = 65 years) and sex. EDV and ESV indices (corrected for body surface area) decreased whilst EF increased with age. There was no difference in LV myocardial mass index between the age groups, but midventricular wall thickness was significantly higher in older people. Mass-to-volume ratio also increased with age. In contrast to EF, mitral annular displacement declined with age. Midventricular LV wall thickness, myocardial mass index and mass-to-volume ratio were higher in men than in women but there were no differences in measures of global and longitudinal LV systolic function. CONCLUSIONS: Due to smaller LV volumes but higher wall thickness, myocardial mass remains unchanged with age. We have found an age-related increase in EF and reduction in longitudinal LV function in apparently normal subjects. This must be borne in mind when assessing older patients with possible heart failure and normal LV systolic function. Men have higher myocardial mass than women.

Renal artery stenosis: an innocent bystander or an independent predictor of worse outcome in patients with chronic heart failure? A magnetic resonance imaging study.

AIMS: To investigate the prognostic impact of atherosclerotic renovascular disease in patients with chronic heart failure. METHODS AND RESULTS: Patients with heart failure due to left ventricular systolic dysfunction underwent cardiac magnetic resonance imaging and contrast-enhanced magnetic resonance angiography. Renal artery stenosis (RAS) was defined as a luminal narrowing >50%. Of the 366 patients investigated, 112 (31%) had RAS, of whom 41 had bilateral RAS. Patients with RAS were older (P < 0.001), had higher blood pressure (P < 0.001), and worse renal function (P = 0.001). In addition, these patients had more admissions and more prolonged hospital stays because of vascular events (0.09 ± 0.26 vs. 0.02 ± 0.16 admissions/per patient/year; P < 0.001; and 1.26 ± 5.79 vs. 0.31 ± 2.54 days/per patient/year; P < 0.001, respectively) and worse prognosis (hazard ratio 1.60, 95% confidence interval 1.10-2.34, P = 0.015). However, in multivariable analysis, a history of diabetes mellitus, decreasing haemoglobin, and increasing left ventricular end-systolic volume index, but not age and RAS, were independently related to outcome. CONCLUSIONS: RAS is a common finding in patients suffering from heart failure. Although it is associated with an increased vascular morbidity, it is not an independent predictor of mortality.

Relationship between right ventricular volumes measured by cardiac magnetic resonance imaging and prognosis in patients with chronic heart failure.

AIMS: The aim of this study was to investigate the prognostic impact of right ventricular (RV) size in patients with chronic heart failure. METHODS AND RESULTS: Normal volunteers (n = 80) and patients (n = 380) with left ventricular (LV) ejection fraction <45% on echocardiography and on optimal treatment for heart failure underwent cardiac magnetic resonance imaging with measurement of LV and RV volumes, mass and ejection fraction. The mean and the standard deviation (SD) of the RV end-systolic volume index in normal subjects were used to define the normal range as: mean RV end-systolic volume index +2 SD. Patients with dilated RV (>2 SD beyond the mean) (25%) had more frequent evidence of fluid overload in clinical examination and greater LV dimensions (P < 0.0001). During follow-up (median 45, interquartile range: 28-66 months), 37% of patients with and 24% without RV dilation died (log-rank test = 8.4; P = 0.004). In a multivariable Cox regression model, including 13 other clinical variables, RV (HR: 1.08/10 mL/m(2), 95% CI: 1.00-1.18, P = 0.044), but not LV, end-systolic volume index predicted a worse outcome. CONCLUSION: Twenty-five per cent of patients with heart failure due to LV systolic dysfunction have a dilated right ventricle. Greater RV dimensions predict mortality in patients with chronic heart failure. Treatments aimed at preserving or enhancing RV structure and function, possibly by unloading the RV by reducing pulmonary vascular resistance or left atrial pressure, should be investigated.