The 20 year evolution of dobutamine stress cardiovascular magnetic resonance.

Over the past 20 years, investigators world-wide have developed and utilized dobutamine magnetic resonance stress testing procedures for the purpose of identifying ischemia, viability, and cardiac prognosis. This article traces these developments and reviews the data utilized to substantiate this relatively new noninvasive imaging procedure.

Intraperitoneal fat is associated with thickening of the thoracic aorta in individuals at high risk for cardiovascular events.

Increased intraperitoneal (IP) fat is associated with increased cardiovascular (CV) risk, but mechanisms for this increase in risk are not completely established. We performed this study to assess whether IP fat is associated with ascending aortic wall thickness (AOWT), a risk factor for CV events. Four hundred and forty-one consecutive participants, aged 55-85 years, with risk factors for CV events underwent magnetic resonance measures of AOWT and abdominal fat (subcutaneous (SC) fat + IP fat). For the ascending aorta, mean wall thickness of the 4th quartile of the IP fat was higher relative to the 1st quartile (P ≤ 0.001). This difference persisted after accounting for SC fat (P ≤ 0.001), as well as age, gender, height, weight, smoking, diabetes, hypertension, low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol (HDL-C), and C-reactive protein (CRP) (P < 0.03). Elevated IP fat volume is associated with an increase in ascending AOWT, a condition that promotes CV events in middle aged and elderly adults.

Impaired left ventricular stroke volume reserve during clinical dobutamine stress predicts future episodes of pulmonary edema.

OBJECTIVES: The purpose of this study was to determine whether dobutamine-induced abnormal stress changes in left ventricular stroke volume (LVSV) and aortic stiffness predict future pulmonary edema. BACKGROUND: Increased aortic stiffness that decreases LVSV during adrenergic stress may serve as a marker for future pulmonary edema (PE). METHODS: We measured LVSV, ventriculovascular stiffness (pulse pressure/LVSV(index)), and aortic distensibility at rest and during intravenous dobutamine administration using cardiovascular magnetic resonance. Personnel blinded to dobutamine cardiovascular magnetic resonance followed participants longitudinally over time to identify those admitted to the hospital with PE. Data for 44 participants who had a hospital admission for PE were compared with data for 72 participants of similar age, sex, and resting left ventricular ejection fraction who remained PE free. RESULTS: Expressed as median and interquartile range, participants with and without PE exhibited a decreased stress/rest LVSV ratio (0.9 [range 0.7 to 1.1] vs. 1.0 [range 0.9 to 1.2], respectively; p = 0.002), an increased ventriculovascular stiffness stress/rest ratio (1.4 [range 1.0 to 1.6] vs. 1.0 [range 0.8 to 1.3], respectively; p ≤ 0.001); and a decreased stress-induced measure of aortic distensibility (0.8 mm Hg(-3) [range 0.3 to 1.3 mm Hg(-3)] vs. 1.6 mm Hg(-3) [range 1.2 to 3.2 mm Hg(-3)], respectively; p = 0.002). After accounting for age, sex, left ventricular ejection fraction, risk factors for PE, and the presence of dobutamine-induced ischemia, LVSV reserve and the stress/rest ventriculovascular stiffness ratio still differed (p < 0.008 for both) in those with and without PE. CONCLUSIONS: In patients without inducible ischemia during dobutamine stress testing in whom one might otherwise assume a favorable prognosis, the failure to increase LVSV or an increase in ventriculovascular stiffness indicates patients at risk of subsequent PE.

The effect of renal dysfunction on BNP, NT-proBNP, and their ratio.

We examined the effect of renal dysfunction on B-natriuretic peptide (BNP), N-terminal (NT)-proBNP, and their molar ratio at varying severities of cardiac function in 94 Thai patients with chest pain (52 men; 32 women), also measuring creatinine and left ventricular ejection fraction (LVEF). Renal function was classified into 5 stages by estimated glomerular filtration rate. The molar NT-proBNP/BNP ratio was calculated. Cardiac status was classified by LVEF (normal, >50%; moderate, 35%-50%; severe, <35%). BNP, NT-proBNP, and their ratio corresponded to renal disease stage exponential (0.51, 1.05, and 0.54, respectively; correlation coefficients, >or=0.95). BNP and the ratio are affected less than NT-proBNP by renal dysfunction, starting in stage III; NT-proBNP expresses effects starting in stage II. NT-proBNP is more sensitive than BNP to renal disease stage. For log of geometric means vs stage of renal disease, the BNP slopes and correlation coefficients vary considerably (slopes, 0.036-0.531; r(2), 0.017-0.99). The NT-proBNP slopes and regression coefficients vary considerably (slopes, 0.18-0.71; r(2), 0.33-0.99). For the ratio, the slopes show low variation (0.148-0.337), r(2) greater than 0.96, women differing from men (P = .012). The effect of renal disease differs by gender. BNP and NT-proBNP increase by stage III for women but not for men. One must consider renal function, gender, and LVEF when using BNP or NT-proBNP as cardiac biomarkers. The ratio of the 2 peptides is the most consistent marker across LVEFs.

Left ventricular hypertrophy influences cardiac prognosis in patients undergoing dobutamine cardiac stress testing.

BACKGROUND: This study was performed to determine the utility of dobutamine stress test results for predicting myocardial infarction (MI) and cardiac death in patients with chest pain and left ventricular hypertrophy (LVH). METHODS AND RESULTS: Three hundred fifty-three participants with a mean+/-SD age of 64+/-12 years (54%men) underwent dobutamine cardiovascular magnetic resonance stress testing and then were followed up for 6+/-2 years (mean+/-SD; range, 0.5-11.5) to assess the post-dobutamine cardiovascular magnetic resonance stress test occurrence of MI or cardiac death. LV mass and the presence or absence of ischemia were determined; LVH was defined as an LV mass index >96 g/m(2) in men and >77 g/m(2) in women. LVH was present in 62 participants (18% of the men and 17% of the women, P=0.90). Seventy-one (20%) participants experienced an MI or cardiac death during follow-up. The MI and cardiac death rate was more frequent in those with versus without LVH (32% vs 17%, P=0.009). In multivariable analysis that accounted for the presence of preexisting coronary artery disease, hypertension, diabetes, stress-induced ischemia, and reduced LV ejection fraction, LVH was an independent predictor of MI and cardiac death (hazard ratio=1.99; 95% CI, 1.13-3.50; P=0.02). CONCLUSIONS: LVH is predictive of future MI and cardiac death in patients with or without inducible ischemia during dobutamine cardiac stress testing. As a result, LVH should be reported in those referred for dobutamine cardiac stress tests, particularly in those without inducible ischemia, in whom one would otherwise assume a favorable cardiac prognosis.