Novel protein therapeutics for systolic heart failure: chronic subcutaneous B-type natriuretic peptide

OBJECTIVES

The purpose of the present study was to translate our laboratory investigations to establish safety and efficacy of 8 weeks of chronic SC B-type natriuretic peptide (BNP) administration in human Stage C heart failure (HF).

BACKGROUND

B-Type natriuretic peptide is a cardiac hormone with vasodilating, natriuretic, renin-angiotensin inhibiting, and lusitropic properties. We have previously demonstrated that chronic cardiac hormone replacement with subcutaneous (SC) administration of BNP in experimental HF resulted in improved cardiovascular function.

METHODS

We performed a randomized double-blind placebo-controlled proof of concept study comparing 8 weeks of SC BNP (10 μg/kg bid) (n = 20) with placebo (n = 20) in patients with ejection fraction <35% and New York Heart Association functional class II to III HF. Primary outcomes were left ventricular (LV) volumes and LV mass determined by cardiac magnetic resonance imaging. Secondary outcomes include LV filling pressure by Doppler echo, humoral function, and renal function.

RESULTS

Eight weeks of chronic SC BNP resulted in a greater reduction of LV systolic and diastolic volume index and LV mass index as compared with placebo. There was a significantly greater improvement of Minnesota Living with Heart Failure score, LV filling pressure as demonstrated by the reductions of E/e' ratio, and decrease in left atrial volume index as compared with placebo. Glomerular filtration rate was preserved with SC BNP, as was the ability to activate plasma 3',5'-cyclic guanosine monophosphate (p < 0.05 vs. placebo).

CONCLUSIONS

In this pilot proof of concept study, chronic protein therapy with SC BNP improved LV remodeling, LV filling pressure, and Minnesota Living with Heart Failure score in patients with stable systolic HF on optimal therapy. Renin-angiotensin was suppressed, and glomerular filtration rate was preserved. Subcutaneous BNP represents a novel, safe, and efficacious protein therapeutic strategy in human HF. Further studies are warranted to determine whether these physiologic observations can be translated into improved clinical outcomes and ultimately delay the progression of HF. (Cardiac Hormone Replacement With BNP in Heart Failure: A Novel Therapeutic Strategy; NCT00252187).

Comorbidity and ventricular and vascular structure and function in heart failure with preserved ejection fraction: a community-based study

BACKGROUND

Patients with heart failure and preserved ejection fraction (HFpEF) display increased adiposity and multiple comorbidities, factors that in themselves may influence cardiovascular structure and function. This has sparked debate as to whether HFpEF represents a distinct disease or an amalgamation of comorbidities. We hypothesized that fundamental cardiovascular structural and functional alterations are characteristic of HFpEF, even after accounting for body size and comorbidities.

METHODS AND RESULTS

Comorbidity-adjusted cardiovascular structural and functional parameters scaled to independently generated and age-appropriate allometric powers were compared in community-based cohorts of HFpEF patients (n=386) and age/sex-matched healthy n=193 and hypertensive, n=386 controls. Within HFpEF patients, body size and concomitant comorbidity-adjusted cardiovascular structural and functional parameters and survival were compared in those with and without individual comorbidities. Among HFpEF patients, comorbidities (obesity, anemia, diabetes mellitus, and renal dysfunction) were each associated with unique clinical, structural, functional, and prognostic profiles. However, after accounting for age, sex, body size, and comorbidities, greater concentric hypertrophy, atrial enlargement and systolic, diastolic, and vascular dysfunction were consistently observed in HFpEF compared with age/sex-matched normotensive and hypertensive.

CONCLUSIONS

Comorbidities influence ventricular-vascular properties and outcomes in HFpEF, yet fundamental disease-specific changes in cardiovascular structure and function underlie this disorder. These data support the search for mechanistically targeted therapies in this disease.

Longitudinal changes in ejection fraction in heart failure patients with preserved and reduced ejection fraction

BACKGROUND

Heart failure (HF) can occur in patients with preserved (HFpEF, EF≥50%) or reduced (HFrEF, EF<50%) ejection fraction (EF), but changes in EF after HF diagnosis are not well described.

METHODS AND RESULTS

Among a community cohort of incident HF patients diagnosed from 1984 to 2009 in Olmsted County, Minnesota, we obtained all EFs assessed by echocardiography from initial HF diagnosis until death or last follow-up through March 2010. Mixed effects models fit a unique linear regression line for each person using serial EF data. Compiled results allowed estimates of the change in EF over time in HFpEF and HFrEF. Among 1233 HF patients (48.3% male, mean age 75.0 years, mean follow-up 5.1 years), 559 (45.3%) had HFpEF at diagnosis. In HFpEF, on average, EF decreased by 5.8% over 5 years (P<0.001) with greater declines in older individuals and those with coronary disease. Conversely, EF increased in HFrEF (average increase 6.9% over 5 years, P<0.001). Greater increases were noted in women, younger patients, individuals without coronary disease, and those treated with evidence-based medications. Overall, 39% of HFpEF patients had an EF<50% and 39% of HFrEF patients had an EF≥50% at some point after diagnosis. Decreases in EF over time were associated with reduced survival whereas increases in EF were associated with improved survival.

CONCLUSIONS

These data suggest that progressive contractile dysfunction may contribute to the pathophysiology of HFpEF. Prospective longitudinal studies are needed to confirm these observations and establish the mechanism and clinical relevance of decline in EF over time in HFpEF.

Diastolic stiffness as assessed by diastolic wall strain is associated with adverse remodelling and poor outcomes in heart failure with preserved ejection fraction

AIMS

The pathophysiology of heart failure with preserved ejection fraction (HFpEF) is complex but increased left ventricular (LV) diastolic stiffness plays a key role. A load-independent, non-invasive, direct measure of diastolic stiffness is lacking. The diastolic wall strain (DWS) index is based on the linear elastic theory, which predicts that impaired diastolic wall thinning reflects resistance to deformation in diastole and thus, increased diastolic myocardial stiffness. The objectives of this community-based study were to determine the distribution of this novel index in consecutive HFpEF patients and healthy controls, define the relationship between DWS and cardiac structure and function and determine whether increased diastolic stiffness as assessed by DWS is predictive of the outcome in HFpEF.

METHODS AND RESULTS

Consecutive HFpEF patients (n = 327, EF ≥ 50%) and controls (n = 528) from the same community were studied. Diastolic wall strain was lower in HFpEF (0.33 ± 0.08) than in controls (0.40 ± 0.07, P < 0.001). Within HFpEF, those with DWS ≤ median (0.33) had higher LV mass index, relative wall thickness, E/e', Doppler-estimated LV end-diastolic pressure to LV end-diastolic volume ratio, left atrial volume index, and brain natriuretic peptide (BNP) levels than those with DWS > median. Heart failure with preserved ejection fraction patients with DWS ≤ median had higher rate of death or HF hospitalization than those with DWS > median (P = 0.003) even after the adjustment for age, gender, log BNP, LV geometry, or log E/e' (P < 0.01).

CONCLUSION

These data suggest that DWS, a simple index, is useful in assessing diastolic stiffness and that more advanced diastolic stiffness is associated with worse outcomes in HFpEF.

Variable phenotype in murine transverse aortic constriction

BACKGROUND

In mice, transverse aortic constriction (TAC) is variably characterized as a model of pressure overload-induced hypertrophy (left ventricular [LV] hypertrophy, or LVH) or heart failure (HF). While commonly used, variability in the TAC model is poorly defined. The objectives of this study were to characterize the variability in the TAC model and to define a simple, noninvasive method of prospectively identifying mice with HF versus compensated LVH after TAC.

METHODS

Eight-week-old male C57BL/6J mice underwent TAC or sham and then echocardiography at 3 weeks post-TAC. A group of sham and TAC mice were euthanized after the 3-week echocardiogram, while the remainder underwent repeat echocardiography and were euthanized at 9 weeks post-TAC. The presence of TAC was assessed with two-dimensional echocardiography, anatomic aortic m-mode and color flow, and pulsed-wave Doppler examination of the transverse aorta (TA) and by LV systolic pressure (LVP). Trans-TAC pressure gradient was assessed invasively in a subset of mice. HF was defined as lung/body weight>upper limit in sham-operated mice.

RESULTS

As compared with sham, TAC mice had higher TA velocity, LVP and LV weight, and lower ejection fraction (EF) at 3 or 9 weeks post-TAC. Only a subset of TAC mice (28%) developed HF. As compared with compensated LVH, HF mice were characterized by similar TA velocity and higher percent TA stenosis, but lower LVP, higher LV weight, larger LV cavity, lower EF and stress-corrected midwall fiber shortening, and more fibrosis. Both EF and LV mass measured by echocardiography at 3 weeks post-TAC were predictive of the presence of HF at 3 or 9 weeks post-TAC.

CONCLUSIONS

In wild-type mice, TAC produces a variable cardiac phenotype. Marked abnormalities in LV mass and EF at echocardiography 3 weeks post-TAC identify mice with HF at autopsy. These data are relevant to appropriate design and interpretation of murine studies.

Effects of vasodilation in heart failure with preserved or reduced ejection fraction implications of distinct pathophysiologies on response to therapy

OBJECTIVES

The purpose of this study was to compare hemodynamic responses to vasodilator therapy in patients with heart failure (HF) and preserved ejection fraction (HFpEF) versus HF and reduced ejection fraction (HFrEF).

BACKGROUND

There is no proven therapy for HFpEF. In the absence of data, medicines with established benefit in HFrEF such as vasodilators are frequently prescribed for HFpEF.

METHODS

We compared baseline hemodynamics and acute responses to vasodilation with intravenous sodium nitroprusside in patients with HFrEF (n = 174) and HFpEF (n = 83), determined invasively by cardiac catheterization.

RESULTS

Baseline blood pressure, stroke volume, and cardiac output were greater in HFpEF than HFrEF, while pulmonary artery mean and pulmonary wedge pressures were similar. Left ventricular filling pressures were reduced to a similar extent in each group with nitroprusside, but the drop in systemic arterial pressure was 2.6-fold greater in HFpEF (p < 0.0001), and improvements in stroke volume and cardiac output were each ∼60% lower in HFpEF compared to HFrEF (p < 0.0001). Despite similarly elevated filling pressures, HFpEF patients were fourfold more likely than HFrEF to experience a reduction in stroke volume with nitroprusside (p < 0.0001), suggesting greater vulnerability to preload reduction. Pulmonary artery systolic pressure dropped more in HFpEF than in HFrEF despite similar reduction in pulmonary mean pressure and resistance, suggesting higher right ventricular systolic elastance in HFpEF.

CONCLUSIONS

As compared to patients with HFrEF, patients with HFpEF experience greater blood pressure reduction, less enhancement in cardiac output, and greater likelihood of stroke volume drop with vasodilators. These findings emphasize fundamental differences in the 2 HF phenotypes and suggest that more pathophysiologically targeted therapies are needed for HFpEF.

Pulmonary pressures and death in heart failure: a community study

OBJECTIVES

The purpose of this study was to determine among community patients with heart failure (HF) whether pulmonary artery systolic pressure (PASP) assessed by Doppler echocardiography was associated with death and improved risk prediction over established factors, using the integrated discrimination improvement and net reclassification improvement.

BACKGROUND

Although several studies have focused on idiopathic pulmonary arterial hypertension, less is known about pulmonary hypertension among patients with HF, particularly about its prognostic value in the community.

METHODS

Between 2003 and 2010, Olmsted County residents with HF prospectively underwent assessment of ejection fraction, diastolic function, and PASP by Doppler echocardiography.

RESULTS

PASP was recorded in 1,049 of 1,153 patients (mean age 76 ± 13; 51% women). Median PASP was 48 mm Hg (25th to 75th percentile: 37.0 to 58.0). There were 489 deaths after a follow-up of 2.7 ± 1.9 years. There was a strong positive graded association between PASP and mortality. Increasing PASP was associated with an increased risk of death (hazard ratio [HR]: 1.45, 95% confidence interval [CI]: 1.13 to 1.85 for tertile 2; HR: 2.07, 95% CI: 1.62 to 2.64 for tertile 3 vs. tertile 1), independently of age, sex, comorbidities, ejection fraction, and diastolic function. Adding PASP to models including these clinical characteristics resulted in an increase in the c-statistic from 0.704 to 0.742 (p = 0.007), an integrated discrimination improvement gain of 4.2% (p < 0.001), and a net reclassification improvement of 14.1% (p = 0.002), indicating that PASP improved prediction of death over traditional prognostic factors. All results were similar for cardiovascular death.

CONCLUSIONS

Among community patients with HF, PASP strongly predicts death and provides incremental and clinically relevant prognostic information independently of known predictors of outcomes.

Cardiorenal rescue study in acute decompensated heart failure: rationale and design of CARRESS-HF, for the Heart Failure Clinical Research Network

BACKGROUND

Worsening renal function is common among patients hospitalized for acute decompensated heart failure (ADHF). When this occurs, subsequent management decisions often pit the desire for effective decongestion against concerns about further worsening renal function. There are no evidence-based treatments or guidelines to assist in these difficult management decisions. Ultrafiltration is a potentially attractive alternative to loop diuretics for the management of fluid overload in patients with ADHF and worsening renal function.

METHODS AND RESULTS

The National Heart, Lung, and Blood Institute Heart Failure Clinical Research Network designed a clinical trial to determine if ultrafiltration results in improved renal function and relief of congestion compared with stepped pharmacologic care when assessed 96 hours after randomization in patients with ADHF and cardiorenal syndrome. Enrollment began in June 2008. This paper describes the rationale and design of the Cardiorenal Rescue Study in Acute Decompensated Heart Failure (CARRESS-HF).

CONCLUSIONS

Treating the signs and symptoms of congestion in ADHF is often complicated by worsening renal function. CARRESS-HF compares treatment strategies (ultrafiltration vs stepped pharmacologic care) for the management of worsening renal function in patients with ADHF. The results of the CARRESS-HF trial are expected to provide information and evidence as to the most appropriate approaches for treating this challenging patient population.

Sildenafil and B-type natriuretic peptide acutely phosphorylate titin and improve diastolic distensibility in vivo

BACKGROUND

In vitro studies suggest that phosphorylation of titin reduces myocyte/myofiber stiffness. Titin can be phosphorylated by cGMP-activated protein kinase. Intracellular cGMP production is stimulated by B-type natriuretic peptide (BNP) and degraded by phosphodiesterases, including phosphodiesterase-5A. We hypothesized that a phosphodiesterase-5A inhibitor (sildenafil) alone or in combination with BNP would increase left ventricular diastolic distensibility by phosphorylating titin.

METHODS AND RESULTS

Eight elderly dogs with experimental hypertension and 4 young normal dogs underwent measurement of the end-diastolic pressure-volume relationship during caval occlusion at baseline, after sildenafil, and BNP infusion. To assess diastolic distensibility independently of load/extrinsic forces, the end-diastolic volume at a common end-diastolic pressure on the sequential end-diastolic pressure-volume relationships was measured (left ventricular capacitance). In a separate group of dogs (n=7 old hypertensive and 7 young normal), serial full-thickness left ventricular biopsies were harvested from the beating heart during identical infusions to measure myofilament protein phosphorylation. Plasma cGMP increased with sildenafil and further with BNP (7.31±2.37 to 26.9±10.3 to 70.3±8.1 pmol/mL; P<0.001). Left ventricular diastolic capacitance increased with sildenafil and further with BNP (51.4±16.9 to 53.7±16.8 to 60.0±19.4 mL; P<0.001). Changes were similar in old hypertensive and young normal dogs. There were no effects on phosphorylation of troponin I, troponin T, phospholamban, or myosin light chain-1 or -2. Titin phosphorylation increased with sildenafil and BNP, whereas titin-based cardiomyocyte stiffness decreased.

CONCLUSION

Short-term cGMP-enhancing treatment with sildenafil and BNP improves left ventricular diastolic distensibility in vivo, in part by phosphorylating titin.

Predictive utility of atrial, N-terminal pro-atrial, and N-terminal pro-B-type natriuretic peptides for mortality and cardiovascular events in the general community: a 9-year follow-up study

OBJECTIVE

To determine the predictive value of atrial natriuretic peptide (ANP), N-terminal pro-ANP (NT-proANP), and N-terminal pro-B-type natriuretic peptide (NT-proBNP) for mortality and cardiovascular events in the general population in the absence of overt heart failure (HF).

PARTICIPANTS AND METHODS

We identified a community-based cohort of 2042 individuals. Those with stage C or D HF (n=45) and renal insufficiency (n=6) were excluded from the current study. Of the remaining individuals, 1769 (89%) underwent echocardiography and measurement of plasma ANP, NT-proANP, and NT-proBNP. Participants were followed up from January 1, 1997, to May 1, 2009, for mortality, HF, myocardial infarction (MI), and cerebrovascular accident; median follow-up was 9 years.

RESULTS

After adjustment for conventional clinical risk factors, NT-proANP had significant predictive value for mortality but not for HF, MI, or cerebrovascular accident, whereas ANP lacked any predictive value. The predictive value of NT-proANP for mortality was attenuated after adjustment for structural and functional cardiac abnormalities. In contrast, NT-proBNP had predictive value for mortality, HF, and MI after adjustment for conventional risk factors and retained significance for mortality and HF after adjustment for structural and functional cardiac abnormalities.

CONCLUSION

Our results suggest that NT-proBNP is a more robust cardiac biomarker compared with ANP or NT-proANP and is independently predictive of mortality and HF in the general population free of overt HF.

Pulmonary capillary wedge pressure augments right ventricular pulsatile loading

BACKGROUND

Right ventricular failure from increased pulmonary vascular loading is a major cause of morbidity and mortality, yet its modulation by disease remains poorly understood. We tested the hypotheses that, unlike the systemic circulation, pulmonary vascular resistance (R(PA)) and compliance (C(PA)) are consistently and inversely related regardless of age, pulmonary hypertension, or interstitial fibrosis and that this relation may be changed by elevated pulmonary capillary wedge pressure, augmenting right ventricular pulsatile load.

METHODS AND RESULTS

Several large clinical databases with right heart/pulmonary catheterization data were analyzed to determine the R(PA)-C(PA) relationship with pulmonary hypertension, pulmonary fibrosis, patient age, and varying pulmonary capillary wedge pressure. Patients with suspected or documented pulmonary hypertension (n=1009) and normal pulmonary capillary wedge pressure displayed a consistent R(PA)-C(PA) hyperbolic (inverse) dependence, C(PA)=0.564/(0.047+R(PA)), with a near-constant resistance-compliance product (0.48±0.17 seconds). In the same patients, the systemic resistance-compliance product was highly variable. Severe pulmonary fibrosis (n=89) did not change the R(PA)-C(PA) relation. Increasing patient age led to a very small but statistically significant change in the relation. However, elevation of the pulmonary capillary wedge pressure (n=8142) had a larger impact, significantly lowering C(PA) for any R(PA) and negatively correlating with the resistance-compliance product (P<0.0001).

CONCLUSIONS

Pulmonary hypertension and pulmonary fibrosis do not significantly change the hyperbolic dependence between R(PA) and C(PA), and patient age has only minimal effects. This fixed relationship helps explain the difficulty of reducing total right ventricular afterload by therapies that have a modest impact on mean R(PA). Higher pulmonary capillary wedge pressure appears to enhance net right ventricular afterload by elevating pulsatile, relative to resistive, load and may contribute to right ventricular dysfunction.

Experimental mild renal insufficiency mediates early cardiac apoptosis, fibrosis, and diastolic dysfunction: a kidney-heart connection

Impaired renal function with loss of nephron number in chronic renal disease (CKD) is associated with increased cardiovascular morbidity and mortality. However, the structural and functional cardiac response to early and mild reduction in renal mass is poorly defined. We hypothesized that mild renal impairment produced by unilateral nephrectomy (UNX) would result in early cardiac fibrosis and impaired diastolic function, which would progress to a more global left ventricular (LV) dysfunction. Cardiorenal function and structure were assessed in rats at 4 and 16 wk following UNX or sham operation (Sham); (n = 10 per group). At 4 wk, blood pressure (BP), aldosterone, glomerular filtration rate (GFR), proteinuria, and plasma B-type natriuretic peptide (BNP) were not altered by UNX, representing a model of mild early CKD. However, UNX was associated with significantly greater LV myocardial fibrosis compared with Sham. Importantly, terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining revealed increased apoptosis in the LV myocardium. Further, diastolic dysfunction, assessed by strain echocardiography, but with preserved LVEF, was observed. Changes in genes related to the TGF-β and apoptosis pathways in the LV myocardium were also observed. At 16 wk post-UNX, we observed persistent LV fibrosis and impairment in LV diastolic function. In addition, LV mass significantly increased, as did LVEDd, while there was a reduction in LVEF. Aldosterone, BNP, and proteinuria were increased, while GFR was decreased. The myocardial, structural, and functional alterations were associated with persistent changes in the TGF-β pathway and even more widespread changes in the LV apoptotic pathway. These studies demonstrate that mild renal insufficiency in the rat results in early cardiac fibrosis and impaired diastolic function, which progresses to more global LV remodeling and dysfunction. Thus, these studies importantly advance the concept of a kidney-heart connection in the control of myocardial structure and function.

Impaired natriuretic and renal endocrine response to acute volume expansion in pre-clinical systolic and diastolic dysfunction

OBJECTIVES

We hypothesized an impaired renal endocrine and natriuretic response to volume expansion (VE) in humans with pre-clinical systolic dysfunction (PSD) and pre-clinical diastolic dysfunction (PDD). We further hypothesized that exogenous B-type natriuretic peptide (BNP) could rescue an impaired natriuretic response in PSD and PDD.

BACKGROUND

Recent reports suggest that in early systolic heart failure (HF), there is an impaired natriuretic response to acute VE.

METHODS

PSD was defined as left ventricular ejection fraction <40% without HF symptoms. PDD was defined as ejection fraction >50%, moderate to severe diastolic dysfunction by Doppler criteria, and no HF symptoms. A double-blinded, placebo-controlled, crossover study was employed to determine the renal response to VE (0.25 ml/kg/min of normal saline for 60 min) in the presence and absence of exogenous BNP. Twenty healthy control subjects, 20 PSD subjects, and 18 PDD subjects participated.

RESULTS

In healthy control subjects, urinary cyclic guanosine monophosphate (cGMP) and natriuresis increased after VE. In contrast, among PSD and PDD subjects, there was a paradoxical decrease in urinary cGMP and attenuated natriuresis. Pre-treatment with subcutaneous BNP resulted in similar increases in both urinary cGMP and natriuresis among healthy normal, PSD, and PDD subjects.

CONCLUSIONS

In PSD and PDD, there is impaired renal cGMP activation, which contributes to impaired natriuresis in response to VE. Impaired activation of urinary cGMP and reduced natriuresis may contribute to volume overload and the progression of HF among PSD and PDD subjects. Importantly, the impaired renal excretory response to VE is rescued by exogenous BNP in PSD and PDD.

Abstract P117: Frailty and Outcomes among Heart Failure Patients in the Community

Objective: To determine among community heart failure (HF) patients whether frailty is associated with an increased risk of hospitalization, emergency department (ED) visits and death, independently of comorbidities.

Background: Frailty is associated with adverse outcomes in some populations; however the prognostic value of frailty among HF patients is not fully documented, particularly for healthcare utilization.

Methods: Olmsted, Dodge and Fillmore County residents with HF between 10/2007 and 12/2010 were prospectively recruited to undergo frailty assessment. Frailty was defined as 3 or more of the following: unintentional weight loss >10 lbs. in 1 year, physical exhaustion, weak grip strength, and slowness and low activity measured by the SF-12 physical component score. Intermediate frailty was defined as having 1-2 components. To account for repeated events, Anderson-Gill modeling was used to determine if frailty predicted hospitalization or ED visits. Cox proportional hazards regression examined associations between frailty and death.

Results: Among 409 patients (mean age 73±13, 58% male), 19% were frail and 55% had intermediate frailty. Within one year, 449 hospitalizations, 523 ED visits and 34 deaths occurred. There was a positive graded association between frailty and hospitalization and ED visits (Table). After adjustment for age, sex, ejection fraction and comorbidity, frailty was associated with an 80% increased risk of hospitalization and a 60% increased risk of ED visits. Frailty was also associated with more than a 2-fold increased risk of death after adjustment.

Conclusion: In the community, frailty is prevalent and is a strong and independent predictor of hospitalizations, ED visits and death among HF patients. As it is independent from coexisting comorbidities, frailty defines new avenues for intervention and should be formally assessed clinically.

Abstract P114: Longitudinal Use of Echocardiography After Heart Failure Diagnosis in the Community

Background: Echocardiography is an important component of the assessment of patients with heart failure (HF). However, its longitudinal use after initial HF diagnosis has not been evaluated.

Methods: We studied patterns of echocardiogram use after HF diagnosis among a random sample of validated incident HF cases in Olmsted County, Minnesota, from 1987 to 2006.

Results: Among 1472 HF patients (mean age 76.0 years, 45% male), 4817 echocardiograms were obtained over a mean follow-up of 5.1 years. The majority were transthoracic (n=3952, 82%), with fewer transesophageal (n=604, 13%) and stress (n=250, 5%) studies obtained. Most patients died during follow-up (n=1126, 76%), and thus had their entire lifetime after HF diagnosis captured. The number of echocardiograms per person ranged from 0-38 (Figure) with a median (25 th , 75 th percentile) of 2 (1, 4). The mean rate of echocardiograms obtained per 10 years of follow-up was 6.4, and increased over time with mean echocardiograms per 10 years follow-up of 4.9, 5.9, 7.2, and 7.8 for persons diagnosed from 1987-1991, 1992-96, 1997-2001, and 2002-06, respectively (p for trend <0.001). Men had echocardiograms more frequently than women (7.2 vs. 5.7 per 10 person years follow-up, p<0.001). Patients who were younger at diagnosis had more frequent echocardiography with rates of 7.1, 6.8, and 5.2 per 10 years follow-up for those who were <70 years, 70-79 years, and 80 years or older at diagnosis (p for trend <0.001).

Conclusions: Most patients have multiple echocardiograms performed after HF diagnosis, and echocardiography use in patients with HF has increased over time. Men and younger patients have higher rates of use after HF diagnosis.

Influence of sex and hormone status on circulating natriuretic peptides

OBJECTIVES

The aim of this study was to assess the relationship between sex hormones and natriuretic peptide levels in community-based adults.

BACKGROUND

Women have higher circulating natriuretic peptide concentrations than men, but the mechanisms for these sex-related differences and the impact of hormone therapy are unclear. Experimental studies suggest that androgens may suppress natriuretic peptide secretion.

METHODS

We measured N-terminal pro-B-type natriuretic peptide (NT-proBNP), total testosterone, and sex hormone-binding globulin plasma levels in 4,056 men and women (mean age 40 ± 9 years) from the Framingham Heart Study Third-Generation cohort. Sex/hormone status was grouped as: 1) men; 2) post-menopausal women not receiving hormone replacement therapy; 3) pre-menopausal women not receiving hormonal contraceptives; 4) post-menopausal women receiving hormone replacement therapy; and 5) pre-menopausal women receiving hormonal contraceptives.

RESULTS

Circulating NT-proBNP levels were associated with sex/hormone status (overall p < 0.0001). Men had lower NT-proBNP levels than women of all menopause or hormone groups, and women receiving hormonal contraceptives had higher NT-proBNP levels than women who were not receiving hormone therapy (all p < 0.0001). These relationships remained significant after adjusting for age, body mass index, and cardiovascular risk factors. Across sex/hormone status groups, free testosterone (FT) levels decreased and sex hormone-binding globulin levels increased in tandem with increasing NT-proBNP levels. In sex-specific analyses, NT-proBNP levels decreased across increasing quartiles of FT in men (p for trend <0.01) and women (p for trend <0.0001). Adjustment for FT markedly attenuated the association between sex/hormone status and NT-proBNP concentrations.

CONCLUSIONS

These findings suggest that lower levels of circulating androgens and the potentiating effect of exogenous female hormone therapy contribute to the higher circulating NT-proBNP concentrations in women.

A genetic variant of the atrial natriuretic peptide gene is associated with cardiometabolic protection in the general community

OBJECTIVES

We sought to define the cardiometabolic phenotype associated with rs5068, a genetic variant of the atrial natriuretic peptide (ANP) gene.

BACKGROUND

The ANP and B-type natriuretic peptide play an important role in cardiorenal homeostasis but also exert metabolic actions.

METHODS

We genotyped 1,608 randomly selected residents from Olmsted County, Minnesota. Subjects were well-characterized.

RESULTS

Genotype frequencies were: AA 89.9%, AG 9.7%, and GG 0.4%; all subsequent analyses were AA versus AG+GG. The G allele was associated with increased plasma levels of N-terminal pro-atrial natriuretic peptide (p = 0.002), after adjustment for age and sex. The minor allele was also associated with lower body mass index (BMI) (p = 0.006), prevalence of obesity (p = 0.002), waist circumference (p = 0.021), lower levels of C-reactive protein (p = 0.027), and higher values of high-density lipoprotein cholesterol (p = 0.019). The AG+GG group had a lower systolic blood pressure (p = 0.011) and lower prevalence of myocardial infarction (p = 0.042). The minor allele was associated with a lower prevalence of metabolic syndrome (p = 0.025). The associations between the G allele and high-density lipoprotein cholesterol, C-reactive protein values, myocardial infarction, and metabolic syndrome were not significant, after adjusting for BMI; the associations with systolic blood pressure, BMI, obesity, and waist circumference remained significant even after adjusting for N-terminal pro-atrial natriuretic peptide.

CONCLUSIONS

In a random sample of the general U.S. population, the minor allele of rs5068 is associated with a favorable cardiometabolic profile. These findings suggest that rs5068 or genetic loci in linkage disequilibrium might affect susceptibility for cardiometabolic diseases and support the possible protective role of natriuretic peptides by their favorable effects on metabolic function. Replication studies are needed to confirm our findings.

Atrial fibrillation and mortality in heart failure: a community study

BACKGROUND

Heart failure (HF) and atrial fibrillation (AF) share common risk factors and often coexist. The combination of HF and AF may carry a worse prognosis than either condition alone; however, the magnitude of this risk remains controversial and it is not known whether the timing of AF influences the risk of death.

METHODS AND RESULTS

We determined the risk of all-cause mortality in relation to the presence of AF prior to or after HF diagnosis in a community-based cohort of persons diagnosed as having HF between 1983 and 2006. Of 1664 individuals with HF, 553 had a history of AF and 384 developed AF after HF. During a median follow-up of 4.0 years, 450 deaths occurred among persons with prior AF, 314 among those with AF after HF, and 572 among patients without AF. In fully adjusted models, compared with patients without AF, those with AF prior to HF had a 29% increased risk of death, whereas those who developed AF after HF exhibited >2-fold increased risk of death.

CONCLUSIONS

In the community, AF is frequent in the setting of HF and is associated with a large excess risk of death. The magnitude of this excess risk differs markedly according to the timing of AF, with AF developing after HF conferring the largest increased risk of death compared with HF patients without AF.

Progression of left ventricular diastolic dysfunction and risk of heart failure

CONTEXT

Heart failure incidence increases with advancing age, and approximately half of patients with heart failure have preserved left ventricular ejection fraction. Although diastolic dysfunction plays a role in heart failure with preserved ejection fraction, little is known about age-dependent longitudinal changes in diastolic function in community populations.

OBJECTIVE

To measure changes in diastolic function over time and to determine the relationship between diastolic dysfunction and the risk of subsequent heart failure.

DESIGN, SETTING, AND PARTICIPANTS

Population-based cohort of participants enrolled in the Olmsted County Heart Function Study. Randomly selected participants 45 years or older (N = 2042) underwent clinical evaluation, medical record abstraction, and echocardiography (examination 1 [1997-2000]). Diastolic left ventricular function was graded as normal, mild, moderate, or severe by validated Doppler techniques. After 4 years, participants were invited to return for examination 2 (2001-2004). The cohort of participants returning for examination 2 (n = 1402 of 1960 surviving [72%]) then underwent follow-up for ascertainment of new-onset heart failure (2004-2010).

MAIN OUTCOME MEASURES

Change in diastolic function grade and incident heart failure.

RESULTS

During the 4 (SD, 0.3) years between examinations 1 and 2, diastolic dysfunction prevalence increased from 23.8% (95% confidence interval [CI], 21.2%-26.4%) to 39.2% (95% CI, 36.3%-42.2%) (P < .001). Diastolic function grade worsened in 23.4% (95% CI, 20.9%-26.0%) of participants, was unchanged in 67.8% (95% CI, 64.8%-70.6%), and improved in 8.8% (95% CI, 7.1%-10.5%). Worsened diastolic dysfunction was associated with age 65 years or older (odds ratio, 2.85 [95% CI, 1.77-4.72]). During 6.3 (SD, 2.3) years of additional follow-up, heart failure occurred in 2.6% (95% CI, 1.4%-3.8%), 7.8% (95% CI, 5.8%-13.0%), and 12.2% (95% CI, 8.5%-18.4%) of persons whose diastolic function normalized or remained normal, remained or progressed to mild dysfunction, or remained or progressed to moderate or severe dysfunction, respectively (P < .001). Diastolic dysfunction was associated with incident heart failure after adjustment for age, hypertension, diabetes, and coronary artery disease (hazard ratio, 1.81 [95% CI, 1.01-3.48]).

CONCLUSIONS

In a population-based cohort undergoing 4 years of follow-up, prevalence of diastolic dysfunction increased. Diastolic dysfunction was associated with development of heart failure during 6 years of subsequent follow-up.