Lisa Mielniczuk

The Association Between High-Dose Diuretics and Clinical Stability in Ambulatory Chronic Heart Failure Patients

OBJECTIVE In chronic heart failure (HF), diuretic doses increase as the disease progresses, often after hospitalization for instability, and have been associated with worsening renal function and increased mortality. METHODS AND RESULTS A prospective observational analysis of 183 patients in an advanced HF clinic stratified at baseline by diuretic dose (low dose < or = 80 mg, high dose > 80 mg furosemide equivalent) was performed. All patients were followed for 1 year, and the primary outcome was a combined HF event of admission for HF, cardiac transplant, mechanical cardiac support, or death. Compared with patients taking low-dose diuretics (n = 113), patients taking high-dose diuretics (n = 70) had more markers of increased cardiovascular risk and were more likely to have a history of recent instability (33% vs 4.4% in low dose, P < .001). High doses of diuretics were a strong univariate predictor of subsequent HF events (hazard ratio 3.83, 95% confidence interval 1.82-8.54); however, after adjustment for clinical stability, diuretic dose no longer remained significant (hazard ratio 1.53, 95% confidence interval 0.58-4.03). CONCLUSION High-dose diuretics may be more of a marker than a cause of instability. A history of HF stability during the past 6 months is associated with an 80% lower risk of an HF event during the next year, independently of baseline diuretic dose.

Usefulness of Beta-Blocker Therapy and Outcomes in Patients With Pulmonary Arterial Hypertension

Pulmonary arterial hypertension (PAH) is a disorder in which pulmonary arterial remodeling and vasoconstriction progressively lead to right heart failure (HF), exercise intolerance, and high mortality. Beta-blockers have been shown to decrease mortality in left-sided HF, but their efficacy in isolated right HF associated with PAH is uncertain. Patients with PAH may have cardiac co-morbidities for which β-blocker therapy is indicated, and the relative risk benefit of this therapy remains to be proved. This is a prospective cohort study of 94 consecutive patients with PAH divided into 2 groups with and without β-blocker use at baseline. Rate of all-cause mortality, PAH-related hospitalization, change in 6-minute walk test, right ventricular structure and function measured by echocardiography, and hemodynamics measured by right heart catheterization were determined between subjects with and without β-blocker use. Beta-blocker use was common (28%) in this cohort. After a median follow-up of 20 months, changes in pulmonary hemodynamics and right ventricular size and function were similar between groups. There were no statistically significant differences in adverse events including PAH-related hospitalization or all-cause mortality (p = 0.19), presence of right HF by last visit (p = 0.75), or change in last 6-minute walk distance (p = 0.92). In conclusion, β-blocker use is not uncommon in a select group of patients with PAH and cardiac co-morbidities and did not appear to exert detrimental effects in clinical, functional, and hemodynamic outcomes. Further randomized data are needed to evaluate the potential benefits and risks of β-blocker use in patients with PAH.

Relation Between Right Ventricular Function and Increased Right Ventricular [18F]Fluorodeoxyglucose Accumulation in Patients With Heart Failure

Background—Left heart failure is characterized by alterations in metabolic substrate utilization, and metabolic modulation may be a future strategy in the management of heart failure. Little is known about cardiac metabolism in the right ventricle and how it relates to other measures of right ventricular (RV) function. This study was designed to measure glucose metabolism in the right ventricle, as estimated by [18F]fluorodeoxyglucose (FDG) positron emission tomography imaging and to determine the relation between RV function and FDG uptake in patients with heart failure. Methods and Results—A total of 68 patients underwent cardiac [18F]FDG positron emission tomography scanning with measurement of RV FDG uptake as a standardized uptake value. Perfusion imaging was acquired at rest with rubidium-82 or [13N]ammonia. RV function was determined by equilibrium radionuclide ventriculography. Relative RV FDG uptake was determined as the ratio of RV to LV standardized uptake value. Fifty-five percent of these patients had ischemic cardiomyopathy. The mean LV and RV ejection fractions were 21±7% and 35±10%, respectively. There was a correlation between RV ejection fraction and the ratio of RV to LV FDG uptake whether the entire LV myocardium (r=−0.40, P<0.001) or LV free wall (r=−0.43, P<0.001) was used. This relation persisted in the subgroup with nonischemic cardiomyopathy (r=−0.37, P=0.04). RV FDG uptake was weakly related to increased RV systolic pressure but not related to LV size, function, or FDG uptake. The correlation between RV ejection fraction and RV/LV FDG was maintained after partial-volume correction (r=−0.68, P<0.001). Conclusions—RV dysfunction is associated with an increase in RV FDG uptake, the magnitude of which may be correlated with severity.

Estimated glomerular filtration rate, inflammation, and cardiovascular events after an acute coronary syndrome

UNLABELLED Both renal dysfunction and elevated levels of high-sensitivity C-reactive protein (CRP) are associated with a higher risk of cardiovascular (CV) outcomes. However, it remains to be established whether the prognostic value of impaired estimated glomerular filtration rate (GFR) remains after accounting for markers of inflammation. METHODS AND RESULTS Glomerular filtration rate was estimated using the Modification of Diet in Renal Disease equation in 4178 patients with non-ST or ST-elevation acute coronary syndromes, participating in the A to Z trial. The mean estimated GFR was 68 mL/min, with a median baseline CRP of 20.2 mg/L. Both an estimated GFR <60 mL/min (HR 2.13, 95% CI 1.7-2.6) and a CRP in the fourth quartile (HR 1.7, 95% CI 1.4-2.2) were strong univariate predictors of a CV event (composite of CV death, recurrent myocardial infarction, heart failure, or stroke). After adjusting for baseline CRP, GFR <60 mL/min remained a strong multivariate predictor for CV death (HR 1.82, 95% CI 1.1-2.97). Randomization to high-dose statin therapy was associated with a reduction in the CV composite (adjusted HR 0.69, 95% CI 0.5-0.95) irrespective of baseline renal function. CONCLUSIONS In a population of patients without overt renal disease, moderate reductions in estimated GFR remain an important prognostic marker. This increased CV hazard associated with an estimated GFR <60 mL/min is independent and additive to markers of inflammation.

Effects of Short-Term Continuous Positive Airway Pressure on Myocardial Sympathetic Nerve Function and Energetics in Patients With Heart Failure and Obstructive Sleep Apnea A Randomized Study

Background— Heart failure with reduced ejection fraction and obstructive sleep apnea (OSA), 2 states of increased metabolic demand and sympathetic nervous system activation, often coexist. Continuous positive airway pressure (CPAP), which alleviates OSA, can improve ventricular function. It is unknown whether this is due to altered oxidative metabolism or presynaptic sympathetic nerve function. We hypothesized that short-term (6–8 weeks) CPAP in patients with OSA and heart failure with reduced ejection fraction would improve myocardial sympathetic nerve function and energetics. Methods and Results— Forty-five patients with OSA and heart failure with reduced ejection fraction (left ventricular ejection fraction 35.8±9.7% [mean±SD]) were evaluated with the use of echocardiography and 11C-acetate and 11C-hydroxyephedrine positron emission tomography before and ≈6 to 8 weeks after randomization to receive short-term CPAP (n=22) or no CPAP (n=23). Work metabolic index, an estimate of myocardial efficiency, was calculated as follows: (stroke volume index×heart rate×systolic blood pressure÷Kmono), where Kmono is the monoexponential function fit to the myocardial 11C-acetate time-activity data, reflecting oxidative metabolism. Presynaptic sympathetic nerve function was measured with the use of the 11C-hydroxyephedrine retention index. CPAP significantly increased hydroxyephedrine retention versus no CPAP (&Dgr;retention: +0.012 [0.002, 0.021] versus −0.006 [−0.013, 0.005] min−1; P=0.003). There was no significant change in work metabolic index between groups. However, in those with more severe OSA (apnea-hypopnea index >20 events per hour), CPAP significantly increased both work metabolic index and systolic blood pressure (P<0.05). Conclusions— In patients with heart failure with reduced ejection fraction and OSA, short-term CPAP increased hydroxyephedrine retention, indicating improved myocardial sympathetic nerve function, but overall did not affect energetics. In those with more severe OSA, CPAP may improve cardiac efficiency. Further outcome-based investigation of the consequences of CPAP is warranted. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT00756366.

Prognostic Value of Rubidium-82 Positron Emission Tomography in Patients After Heart Transplant

Background—Cardiac allograft vasculopathy is a key prognostic determinant after heart transplant. Detection and risk stratification of patients with cardiac allograft vasculopathy are problematic. Positron emission tomography using rubidium-82 allows quantification of absolute myocardial blood flow and may have utility for risk stratification in this population. Methods and Results—Patients with a history of heart transplant undergoing dipyridamole rubidium-82 positron emission tomography were prospectively enrolled. Myocardial perfusion and left ventricular ejection fraction were recorded. Absolute flow quantification at rest and after dipyridamole stress as well as the ratio of mean global flow at stress and at rest, termed myocardial flow reserve, were calculated. Patients were followed for all-cause death, acute coronary syndrome, and heart failure hospitalization. A total of 140 patients (81% men; median age, 62 years; median follow-up, 18.2 months) were included. There were 14 events during follow-up (9 deaths, 1 acute coronary syndrome, and 4 heart failure admissions). In addition to baseline clinical variables (estimated glomerular filtration rate, previously documented cardiac allograft vasculopathy), relative perfusion defects, mean myocardial flow reserve, and mean stress myocardial blood flow were significant predictors of adverse outcome. Conclusions—Abnormalities on rubidium-82 positron emission tomography were predictors of adverse events in heart transplant patients. Larger prospective studies are required to confirm these findings.

The Prognostic Value of Rb-82 Positron Emission Tomography in Patients Following Heart Transplant

Background—Cardiac allograft vasculopathy is a key prognostic determinant after heart transplant. Detection and risk stratification of patients with cardiac allograft vasculopathy are problematic. Positron emission tomography using rubidium-82 allows quantification of absolute myocardial blood flow and may have utility for risk stratification in this population. Methods and Results—Patients with a history of heart transplant undergoing dipyridamole rubidium-82 positron emission tomography were prospectively enrolled. Myocardial perfusion and left ventricular ejection fraction were recorded. Absolute flow quantification at rest and after dipyridamole stress as well as the ratio of mean global flow at stress and at rest, termed myocardial flow reserve, were calculated. Patients were followed for all-cause death, acute coronary syndrome, and heart failure hospitalization. A total of 140 patients (81% men; median age, 62 years; median follow-up, 18.2 months) were included. There were 14 events during follow-up (9 deaths, 1 acute coronary syndrome, and 4 heart failure admissions). In addition to baseline clinical variables (estimated glomerular filtration rate, previously documented cardiac allograft vasculopathy), relative perfusion defects, mean myocardial flow reserve, and mean stress myocardial blood flow were significant predictors of adverse outcome. Conclusions—Abnormalities on rubidium-82 positron emission tomography were predictors of adverse events in heart transplant patients. Larger prospective studies are required to confirm these findings.

Alternative Imaging Modalities in Ischemic Heart Failure (AIMI-HF) IMAGE HF Project I-A: study protocol for a randomized controlled trial

BackgroundIschemic heart disease (IHD) is the most common cause of heart failure (HF); however, the role of revascularization in these patients is still unclear. Consensus on proper use of cardiac imaging to help determine which candidates should be considered for revascularization has been hindered by the absence of clinical studies that objectively and prospectively compare the prognostic information of each test obtained using both standard and advanced imaging.Methods/DesignThis paper describes the design and methods to be used in the Alternative Imaging Modalities in Ischemic Heart Failure (AIMI-HF) multi-center trial. The primary objective is to compare the effect of HF imaging strategies on the composite clinical endpoint of cardiac death, myocardial infarction (MI), cardiac arrest and re-hospitalization for cardiac causes.In AIMI-HF, patients with HF of ischemic etiology (n = 1,261) will follow HF imaging strategy algorithms according to the question(s) asked by the physicians (for example, Is there ischemia and/or viability?), in agreement with local practices. Patients will be randomized to either standard (SPECT, Single photon emission computed tomography) imaging modalities for ischemia and/or viability or advanced imaging modalities: cardiac magnetic resonance imaging (CMR) or positron emission tomography (PET). In addition, eligible and consenting patients who could not be randomized, but were allocated to standard or advanced imaging based on clinical decisions, will be included in a registry.DiscussionAIMI-HF will be the largest randomized trial evaluating the role of standard and advanced imaging modalities in the management of ischemic cardiomyopathy and heart failure. This trial will complement the results of the Surgical Treatment for Ischemic Heart Failure (STICH) viability substudy and the PET and Recovery Following Revascularization (PARR-2) trial. The results will provide policy makers with data to support (or not) further investment in and wider dissemination of alternative ‘advanced’ imaging technologies.Trial registrationNCT01288560

Acute Decline in Renal Function, Inflammation, and Cardiovascular Risk after an Acute Coronary Syndrome

BACKGROUND AND OBJECTIVES Chronic kidney disease is associated with a higher risk of cardiovascular outcomes. The prognostic significance of worsening renal function has also been shown in various cohorts of cardiac disease; however, the predictors of worsening renal function and the contribution of inflammation remains to be established. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Worsening renal function was defined as a 25% or more decrease in estimated GFR (eGFR) over a 1-mo period in patients after a non-ST or ST elevation acute coronary syndromes participating in the Aggrastat-to-Zocor Trial; this occurred in 5% of the 3795 participants. RESULTS A baseline C-reactive protein (CRP) in the fourth quartile was a significant predictor of developing worsening renal function (odds ratio, 2.48; 95% confidence interval, 1.49, 4.14). After adjusting for baseline CRP and eGFR, worsening renal function remained a strong multivariate predictor for the combined cardiovascular composite of CV death, recurrent myocardial infarction (MI), heart failure or stroke (hazard ratio, 1.6; 95% confidence interval, 1.1, 2.3). CONCLUSIONS Patients with an early decline in renal function after an acute coronary syndrome are at a significant increased risk for recurrent cardiovascular events. CRP is an independent predictor for subsequent decline in renal function and reinforces the idea that inflammation may be related to the pathophysiology of progressive renal disease.

Reduced Myocardial Flow in Heart Failure Patients With Preserved Ejection Fraction

Background—There remains limited insight into the pathophysiology and therapeutic advances directed at improving prognosis for patients with heart failure with preserved ejection fraction (HFpEF). Recent studies have suggested a role for coronary microvascular dysfunction in HFpEF. Rb-82 cardiac positron emission tomography imaging is a noninvasive, quantitative approach to measuring myocardial flow reserve (MFR), a surrogate marker for coronary vascular health. The aim of this study was to determine whether abnormalities exist in MFR in patients with HFpEF without epicardial coronary artery disease. Methods and Results—A total of 376 patients with ejection fraction ≥50%, no known history of obstructive coronary artery disease, and a confirmed diagnosis of heart failure (n=78) were compared with patients with no evidence of heart failure (n=298), further stratified into those with (n=186) and without (n=112) hypertension. Global and regional left ventricular MFR was calculated as stress/rest myocardial blood flow using Rb-82 positron emission tomography. Patients with HFpEF were more likely to be older, female, and have comorbid hypertension, diabetes mellitus, dyslipidemia, atrial fibrillation, anemia, and renal dysfunction. HFpEF was associated with a significant reduction in global MFR (2.16±0.69 in HFpEF versus 2.54±0.80 in hypertensive controls; P<0.02 and 2.89±0.70 in normotensive controls; P<0.001). A diagnosis of HFpEF was associated with 2.62 times greater unadjusted odds of having low global MFR (defined as <2.0) and remained a significant predictor of reduced global MFR after adjusting for comorbidities. Conclusions—HFpEF, in the absence of known history for obstructive epicardial coronary artery disease, is associated with reduced MFR independent of other risk factors.