Faculty Bibliography

PURPOSE: The purpose of this pilot study was to test the impact of language-free, low literacy self-care management patient education materials in an ethnically diverse multilingual heart failure (HF) population. METHODS: A one group pre-test-post-test design measured changes in self-care, knowledge and health-related quality of life (HRQL) after a 1month intervention using language-free, low literacy self-care management patient education materials and delivered by a health educator. RESULTS: The ethnically diverse sample (n=21) was predominately male (72%), 48% Black, 42% Hispanic, and 28% marginal/inadequate literacy. There were significant improvements in self-care and knowledge but not HRQL. CONCLUSIONS: Language-free, low literacy self-care patient education may facilitate improved self-care and knowledge in diverse populations who are at risk for poor HF outcomes.

PURPOSE: Chest pain is a common emergency department (ED) presentation that is often unexplained. Recent evidence suggests that disease of the microvessels (arterioles) as opposed to the coronary artery (conduit artery) could explain one third of these cases, particularly in women. Brachial artery reactivity (BAR) is a validated surrogate measure of coronary artery vasomotion. OBJECTIVES: The goal of this study was to compare brachial artery conduit vessel function (BAR) and microvascular function (postischemic peak reactive hyperemia [RH]) in subjects with and without chest pain and grouped according to sex. METHODS: This prospective cohort study was conducted from January through March 2010. Cases were patients admitted to an ED chest pain center with low to moderate risk of acute coronary syndrome; they were eligible for study if their creatinine level was <2.0 mg/dL and systolic blood pressure was >100 mm Hg or <180 mm Hg. Asymptomatic healthy volunteers on no medications were recruited as control subjects. BAR as a change in brachial artery diameter in response to transient forearm ischemia (endothelium-dependent vasodilation) and RH as a change in flow velocities were measured with a high-resolution ultrasound. Telephone follow-up visits were made at 1 month for recurrence of chest pain and recidivism. FINDINGS: A total of 57 patients and 21 control subjects were enrolled; there was 100% follow-up at 1 month. Most patients (86%) had at least 1 cardiac risk factor. Neither BAR nor RH varied significantly between patients and control subjects (P > 0.05). Symptomatic men had lower mean BAR than women (2.67% vs 6.22%; P < 0.01), even when normalized for shear stress (P = 0.01). Conversely, women with chest pain had lower RH compared with men (2.85 vs 4.61; P = 0.01). The sex-specific differences adjusted for age and Framingham risk scores persisted for BAR (P = 0.003) and RH (P = 0.002). Of 57 patients, 53% had recurrent pain, and 4 returned to the hospital within 1 month. IMPLICATIONS: Differences in BAR and RH in patients ruled out for myocardial infarction suggest that the pathophysiology of acute chest pain might be sex-specific. Men with chest pain exhibited lower BAR, indicating peripheral conduit artery dysfunction. Conversely, women with chest pain exhibited lower postischemic peak hyperemia, indicative of peripheral microvascular dysfunction. Sex differences in pathophysiology of chest pain and vascular dysfunction could inform development of effective therapeutics for patients with recurrent or persistent chest pain in the absence of obstructive coronary artery disease.

Takotsubo cardiomyopathy (TC) often occurs after emotional or physical stress. Norepinephrine levels are unusually high in the acute phase, suggesting a hyperadrenergic mechanism. Comparatively little is known about parasympathetic function in patients with TC. We sought to characterize autonomic function at rest and in response to physical and emotional stimuli in 10 women with a confirmed history of TC and 10 age-matched healthy women. Sympathetic and parasympathetic activity was assessed at rest and during baroreflex stimulation (Valsalva maneuver and tilt testing), cognitive stimulation (Stroop test), and emotional stimulation (event recall, patients). Ambulatory blood pressure monitoring and measurement of brachial artery flow-mediated vasodilation were also performed. TC women (tested an average of 37 months after the event) had excessive pressor responses to cognitive stress (Stroop test: p <0.001 vs baseline and p = 0.03 vs controls) and emotional arousal (recall of TC event: p = 0.03 vs baseline). Pressor responses to hemodynamic stimuli were also amplified (Valsalva overshoot: p <0.05) and prolonged (duration: p <0.01) in the TC women compared with controls. Plasma catecholamine levels did not differ between TC women and controls. Indexes of parasympathetic (vagal) modulation of heart rate induced by respiration and cardiovagal baroreflex gain were significantly decreased in the TC women versus controls. In conclusion, even long after the initial episode, women with previous episode of TC have excessive sympathetic responsiveness and reduced parasympathetic modulation of heart rate. Impaired baroreflex control may therefore play a role in TC.

Iron deficiency is common in heart failure (HF) patients, and is associated with increased risk of adverse clinical outcomes. Clinical trials of intravenous iron supplementation in iron-deficient HF patients have demonstrated short-term improvement in functional capacity and quality of life. In some trials, the benefits of iron supplementation were independent of the hemoglobin levels. Additional investigations of iron supplementation are needed to characterize the mechanisms contributing to clinical benefit and long-term safety in HF.

RATIONALE: Obesity is characterized by increased systemic and pulmonary blood volumes (pulmonary vascular congestion). Concomitant abnormal alveolar membrane diffusion suggests subclinical interstitial edema. In this setting, functional abnormalities should encompass the entire distal lung including the airways. OBJECTIVES: We hypothesize that in obesity: 1) pulmonary vascular congestion will affect the distal lung unit with concordant alveolar membrane and distal airway abnormalities; and 2) the degree of pulmonary congestion and membrane dysfunction will relate to the cardiac response. METHODS: 54 non-smoking obese subjects underwent spirometry, impulse oscillometry (IOS), diffusion capacity (DLCO) with partition into membrane diffusion (DM) and capillary blood volume (VC), and cardiac MRI (n = 24). Alveolar-capillary membrane efficiency was assessed by calculation of DM/VC. MEASUREMENTS AND MAIN RESULTS: Mean age was 45+/-12 years; mean BMI was 44.8+/-7 kg/m2. Vital capacity was 88+/-13% predicted with reduction in functional residual capacity (58+/-12% predicted). Despite normal DLCO (98+/-18% predicted), VC was elevated (135+/-31% predicted) while DM averaged 94+/-22% predicted. DM/VC varied from 0.4 to 1.4 with high values reflecting recruitment of alveolar membrane and low values indicating alveolar membrane dysfunction. The most abnormal IOS (R5 and X5) occurred in subjects with lowest DM/VC (r2 = 0.31, p<0.001; r2 = 0.34, p<0.001). Cardiac output and index (cardiac output / body surface area) were directly related to DM/VC (r2 = 0.41, p<0.001; r2 = 0.19, p = 0.03). Subjects with lower DM/VC demonstrated a cardiac output that remained in the normal range despite presence of obesity. CONCLUSIONS: Global dysfunction of the distal lung (alveolar membrane and distal airway) is associated with pulmonary vascular congestion and failure to achieve the high output state of obesity. Pulmonary vascular congestion and consequent fluid transudation and/or alterations in the structure of the alveolar capillary membrane may be considered often unrecognized causes of airway dysfunction in obesity.

Reduced parasympathetic modulation of heart rate is an independent predictor of mortality in heart failure. It is not known whether enhancing parasympathetic outflow to the heart impacts survival in these patients. Our aim was to evaluate whether the neck collar technique, a noninvasive method of stimulating the carotid baroreceptors, was a reliable and reproducible means to evaluate baroreflex control of heart rate in patients with heart failure. Twenty-five patients (20 males, mean age 54 +/-10-years) with symptomatic heart failure (NYHA class II-III) were studied on two separate days, one week apart. All were free of cholesterol plaques in the carotid arteries. Blood pressure and RR intervals were measured continuously in the seated position. Graded pressure (-70 to +70 mmHg) was administered to the neck during a held expiration using a custom-designed collar. Maximum change in RR intervals was determined during the onset of neck pressure. Stimulus response curves were plotted for changes in RR intervals against estimated-carotid sinus pressure. The technique was well tolerated and there were no adverse events. The maximal differential, used to estimate baroreflex gain, was tightly correlated between visits 1 and 2 (R2= 0.8063, p < 0.0001). The corresponding "set point" of the reflex was also significantly correlated between visits (R2=0.3324 p=0.049). To our knowledge, this is the first time the neck collar technique has been validated in a medically fragile population. The technique is safe and reproducible and maybe useful to help understand whether strategies that enhance parasympathetic activity change outcomes in heart failure