Safety and utility of dobutamine and pressure wire use in the hemodynamic assessment of low-flow, low-gradient aortic stenosis with reduced left ventricular ejection fraction.

BACKGROUND: The ACC/AHA guidelines recommend low-dose dobutamine challenge for hemodynamic assessment of the severity of AS in patients with low flow, low gradient aortic stenosis with reduced ejection fraction (EF) (LFLG-AS; stage D2). Inherent pitfalls of echocardiography could result in inaccurate aortic valve areas (AVA), which have downstream prognostic implications. Data on the safety and efficacy of coronary pressure wire and fluid-filled catheter use for low dose dobutamine infusion is sparse. METHODS: We retrospectively analyzed 39 consecutive patients with EF<50%, AVA<1cm2 and SVI<35ml/m2 on echocardiography who underwent simultaneous right and left heart catheterization. Hemodynamic assessments were performed at baseline and at every increment in the dobutamine infusion rate (The infusion was continued until maximal dose of dobutamine or a mean AV gradient>40mmHg was attained. The occurrence of sustained ventricular arrhythmias, symptomatic hypotension or intolerable symptoms leading to cessation of infusion was recorded. Transient ischemic attacks (TIAs) or clinically apparent strokes periprocedurally or up to 30days after the procedure were recorded. RESULTS: Dobutamine challenge confirmed true AS in 26 patients (67%) and pseudosevere AS in 34%. No sustained arrhythmias, hypotension or cessation of infusion from intolerable symptoms were observed. No clinical strokes or TIAs were observed up to 30days after procedure in any of these patients. CONCLUSIONS: Hemodynamic assessment of AS using a pressure wire with dobutamine challenge is a safe and effective tool in identifying truly severe AS in patients with LFLG-AS with reduced EF.

Left ventricular hypertrophy and risk reclassification for coronary events in multi-ethnic adults.

BACKGROUND: Left ventricular hypertrophy (LVH) has not been evaluated for reclassification improvement in the intermediate Framingham risk category for incident hard coronary events in a large multi ethnic population free of cardiovascular disease at baseline. DESIGN: A post-hoc analysis on the Multi Ethnic Study of Atherosclerosis (MESA) dataset (n = 4921) was performed. METHODS: LVH was defined as the upper 95 th percentile of cardiac magnetic resonance imaging derived left ventricular mass (LVM) indexed based on body surface area (BSA) and height. Multivariate Cox proportional hazards models were used to assess the independent association between LVH and composite outcomes like all cardiovascular disease (CVDa) and hard coronary heart disease (CHDh) events over a mean follow-up period of 4.5 years. To assess the incremental value of LVH over traditional CV risk factors for CHDh prediction, we compared the discrimination, calibration and net reclassification index (NRI) of models comprising of traditional CV risk factors with and without LVH. RESULTS: LVH derived from LVM indexed by BSA (LVH-BSA) and height(1.7)(LVH-height) showed an independent association with CVDa (LVH-BSA: hazard ratio (HR) 1.52, 95% confidence interval (CI) 1.05-2.20, p = 0.03; LVH-height(1.7): HR 1.58, 95% CI 1.14-2.18, p = 0.012) and CHDh (LVH-BSA: HR 2.36, 95% CI 1.37-4.04, p = 0.002; LVH-height(1.7): HR: 1.95, 95% CI: 1.17-3.26, p = 0.01). Addition of LVH to the model based on traditional CV risk factors demonstrated no significant improvement in NRI for CHDh in either the entire cohort (LVH-BSA: NRI 1.7%, 95% CI: -8.3% to 11.7%, p = 0.74; LVH-height(1.7): NRI 2.7%, 95% CI: -5.8% to 11.3%, p = 0.62) or the intermediate risk group (LVH-BSA: NRI 12.0%, 95% CI: -5.7% to 29.8%, p = 0.19; LVH-height(1.7): NRI 14.5%, 0.1% to 28.8%, p = 0.05). CONCLUSIONS: Although an independent predictor of cardiovascular events, LVH does not lead to clinically meaningful reclassification of the overall and intermediate risk population for CHDh.