Utility of positron emission tomography for drug development for heart failure.

Only about 1 in 5,000 investigational agents in a preclinical stage acquires Food and Drug Administration approval. Among many reasons for this includes an inefficient transition from preclinical to clinical phases, which exponentially increase the cost and the delays the process of drug development. Positron emission tomography (PET) is a nuclear imaging technique that has been used for the diagnosis, risk stratification, and guidance of therapy. However, lately with the advance of radiochemistry and of molecular imaging technology, it became evident that PET could help novel drug development process. By using a PET radioligand to report on receptor occupancy during novel agent therapy, it may help assess the effectiveness, efficacy, and safety of such a new medication in an early preclinical stage and help design successful clinical trials even at a later phase. In this article, we explore the potential implications of PET in the development of new heart failure therapies and review PET's application in the respective pathophysiologic pathways such as myocardial perfusion, metabolism, innervation, inflammation, apoptosis, and cardiac remodeling.

Inotrope use and outcomes among patients hospitalized for heart failure: impact of systolic blood pressure, cardiac index, and etiology.

BACKGROUND: Inotropes are widely used in hospitalized systolic heart failure (HF) patients, especially those with low systolic blood pressure (SBP) or cardiac index. In addition, inotropes are considered to be harmful in nonischemic HF. METHODS AND RESULTS: We examined the association of in-hospital inotrope use with (1) major events (death, ventricular assist device, or heart transplant) and (2) study days alive and out of hospital during the first 6 months in the Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness, which excluded patients with immediate need for inotropic therapy. Predefined subgroups of interest were baseline SBP <100 versus ≥ 100 mm Hg, cardiac index <1.8 vs ≥ 1.8 L min(-1) m(-2), and ischemic versus nonischemic HF etiology. Inotropes were frequently used in both the <100 mm Hg (88/165 [53.3%]) and the ≥ 100 mm Hg (106/262 [40.5%]) SBP subgroups and were associated with higher risk for major events in both subgroups (adjusted hazard ratio [HR] 2.85, 95% confidence interval [CI] 1.59-5.12 [P < .001]; and HR 1.86, 95% CI 1.02-3.37 [P = .042]; respectively). Risk with inotropes was more pronounced among those with cardiac index ≥ 1.8 L min(-1) m(-2) (n = 114; HR 4.65, 95% CI 1.98-10.9; P < .001) vs <1.8 L min(-1) m(-2) (n = 82; HR 1.48, 95% CI 0.61-3.58; P = .39). Event rates were higher with inotropes in both ischemic (n = 215; HR 2.64, 95% CI 1.49-4.68; P = .001) and nonischemic (n = 216; HR 2.19, 95% CI 1.18-4.07; P = .012) patients. Across all subgroups, patients who received inotropes spent fewer study days alive and out of hospital. CONCLUSIONS: In the absence of cardiogenic shock or end-organ hypoperfusion, inotrope use during hospitalization for HF was associated with unfavorable 6-month outcomes, regardless of admission SBP, cardiac index, or HF etiology.

The Masquerading Myocarditis: A Case of Late Recurrence of Acute Myocarditis Presenting as "Peripartum Cardiomyopathy".

Myocarditis is a potentially fatal medical condition with varied etiologies. Peripartum cardiomyopathy (PPCM) refers to systolic dysfunction occurring toward the end of pregnancy or in the months following delivery; it is a diagnosis of exclusion. We present a patient with chest pain, bipedal edema, markedly elevated troponins, electrocardiogram (EKG) findings that were concerning for myocardial infarction, and a significantly reduced left ventricular ejection fraction (LVEF) on the echocardiogram. The patient's presentation in the postpartum period closely resembled peripartum cardiomyopathy and presented a peculiar diagnostic challenge to our team. The right diagnosis was possible with cardiac magnetic resonance imaging, which revealed late gadolinium enhancement. Additionally, the patient had positive Coxsackie B5 and Epstein Bar virus serologies. While the clinical course of the disease is often benign, it could rapidly deteriorate, so early recognition and diagnosis are important to ensure patients receive adequate therapeutic support.

Soluble guanylate cyclase: a potential therapeutic target for heart failure.

The number of annual hospitalizations for heart failure (HF) and the mortality rates among patients hospitalized for HF remains unacceptably high. The search continues for safe and effective agents that improve outcomes when added to standard therapy. The nitric oxide (NO)-soluble guanylate cyclase (sGC)-cyclic guanosine monophosphate (cGMP) pathway serves an important physiologic role in both vascular and non-vascular tissues, including regulation of myocardial and renal function, and is disrupted in the setting of HF, leading to decreased protection against myocardial injury, ventricular remodeling, and the cardio-renal syndrome. The impaired NO-sGC-cGMP pathway signaling in HF is secondary to reduced NO bioavailability and an alteration in the redox state of sGC, making it unresponsive to NO. Accordingly, increasing directly the activity of sGC is an attractive pharmacologic strategy. With the development of two novel classes of drugs, sGC stimulators and sGC activators, the hypothesis that restoration of NO-sGC-cGMP signaling is beneficial in HF patients can now be tested. Characterization of these agents in pre-clinical and clinical studies has begun with investigations suggesting both hemodynamic effects and organ-protective properties independent of hemodynamic changes. The latter could prove valuable in long-term low-dose therapy in HF patients. This review will explain the role of the NO-sGC-cGMP pathway in HF pathophysiology and outcomes, data obtained with sGC stimulators and sGC activators in pre-clinical and clinical studies, and a plan for the further clinical development to study these agents as HF therapy.

Acute heart failure: patient characteristics and pathophysiology.

The number of hospitalizations for acute heart failure (HF) continues to increase and it remains the most common discharge diagnosis among Medicare beneficiaries. Prognosis after hospitalization for HF is poor, with high in-hospital mortality and even higher post-discharge mortality and rehospitalization rates. It is a complex clinical syndrome that varies widely with respect to clinical presentation and underlying pathophysiology. This paper reviews what is documented in the literature regarding the known pathophysiologic mechanisms reported in patients hospitalized for HF.

Classification of patients hospitalized for heart failure.

Despite low inpatient mortality and effective symptomatic management, patients hospitalized for heart failure (HHF) experience high postdischarge mortality and rehospitalization rates. HHF represents a widely heterogeneous population with distinct clinical subsets that may require tailored management approaches. Despite this, however, HHF patients are almost uniformly managed with intravenous diuretics, with low uptake of new therapies during hospitalization. This article proposes a practical approach to classifying HHF patients that is focused on guiding individualized inpatient and postdischarge management. HHF is not a single disease but a manifestation of several cardiac and noncardiac processes and thus should be approached as such.

Medication dosing for heart failure with reduced ejection fraction - opportunities and challenges.

Multiple drug classes have shown incremental benefits in heart failure with reduced ejection fraction. Most of these trials were designed to achieve specific doses of the investigational agent. Clinical practice guidelines recommend using the same target dosing of therapies, as tolerated. However, with the increasing number of available therapies, clinicians face the challenge of simultaneously using several drugs, achieving target doses, and managing side effects that are often overlapping. Blood pressure, renal function, hyperkalaemia, and other factors may impede achieving target doses of all medications, leaving clinicians with dilemmas as to how to sequence and dose these various classes of drugs. The guideline-directed eligibility for certain drugs and devices requires stability on maximally tolerated doses of background therapies. However, significant variability exists in dosing achieved in clinical practice. We discuss the existing background data regarding the doses of heart failure medications in clinical trials and in practice, and provide recommendations on how to navigate this complex therapeutic decision-making.

Serum Osmolality and Postdischarge Outcomes After Hospitalization for Heart Failure.

Serum osmolality may fluctuate with neurohormonal activation and in response to certain therapeutics in patients with heart failure (HF). The clinical relevance of osmolality in patients with HF has not been defined. In this post hoc analysis of the Efficacy of Vasopressin Antagonism in Heart Failure: Outcome Study with Tolvaptan trial, we analyzed serum osmolality measured at discharge in 3,744 patients hospitalized for HF and reduced ejection fraction (EF ≤40%). Median follow-up was 9.9 months. The association between discharge osmolality and all-cause mortality (ACM) and composite cardiovascular mortality or HF hospitalization was nonlinear; and thus, patients were divided into low (≤284), normal (285 to 300), and high (≥300 mOsm/kg) osmolality. Median serum osmolality at discharge was 297 (290 to 304) mOsm/kg. Patients in the low osmolality group (n = 454,12.1%) were more likely to be younger, men, have lower rates of hypertension, coronary artery disease, chronic kidney disease, diabetes, and have lower serum sodium, creatinine, systolic blood pressure, and EF (all p <0.001). Low discharge osmolality was associated with higher ACM (low 29.3%; normal 23.6%; high 25.2%; p = 0.04) and the composite endpoint (low 45.6%; normal 39.3%; high 41.8%; p = 0.04). After risk adjustment, a 15 mOsm/kg decrease in osmolality was predictive of higher ACM (hazard ratio 1.61, 95% CI 1.19 to 2.17) and the composite endpoint (hazard ratio 1.37, 95% CI 1.06 to 1.75) in the low osmolality group. These associations were not seen in patients with normal or high osmolality. Interaction analyses for tolvaptan treatment were nonsignificant (p >0.4). In conclusion, low discharge serum osmolality was independently predictive of worse postdischarge mortality and readmission. Further study is required to clarify the clinical utility of serum osmolality in hospitalized patients with HF.

Echocardiographic assessment of pulmonary artery systolic pressure and outcomes in ambulatory heart failure patients.

BACKGROUND: Pulmonary hypertension (PH) in patients with heart failure (HF) is associated with worse outcomes and is rapidly being recognized as a therapeutic target. To facilitate pragmatic research efforts, data regarding the prognostic importance of noninvasively assessed pulmonary artery systolic pressure (PASP) in stable ambulatory patients with HF are needed. METHODS AND RESULTS: We examined the association between echocardiographic PASP and outcomes in 417 outpatients with HF (age, 54 ± 13 years; 60.7% men; 50.4% whites; 24.9% with preserved ejection fraction). Median PASP was 36 mm Hg (interquartile range [IQR]: 29, 46). After a median follow-up of 2.6 years (IQR: 1.7, 3.9) there were 72 major events (57 deaths; 9 urgent heart transplants; and 6 ventricular assist device implantations) and 431 hospitalizations for HF. In models adjusting for clinical risk factors and therapy, a 10-mm Hg higher PASP was associated with 37% higher risk (95% CI: 18, 59; P<0.001) for major events, and 11% higher risk (95% CI: 1, 23; P=0.039) for major events or HF hospitalization. The threshold that maximized the likelihood ratio for both endpoints was 48 mm Hg; those with PASP ≥ 48 mm Hg (N=84; 20.1%) had an adjusted hazard ratio of 3.33 (95% CI: 1.96, 5.65; P<0.001) for major events and 1.47 (95% CI: 1.02, 2.11; P=0.037) for major events or HF hospitalization. Reduced right ventricular systolic function had independent prognostic utility over PASP for adverse outcomes. Right atrial pressure and transtricuspid gradient both contributed to risk. CONCLUSIONS: Elevated PASP, determined by echocardiography, identifies ambulatory patients with HF at increased risk for adverse events.

Soluble tumor necrosis factor receptors and heart failure risk in older adults: Health, Aging, and Body Composition (Health ABC) Study.

BACKGROUND: Tumor necrosis factor (TNF) levels are associated with risk for heart failure (HF). The soluble TNF type 1 (sTNF-R1) and type 2 (sTNF-R2) receptors are elevated in patients with manifest HF, but whether they are associated with risk for incident HF is unclear. METHODS AND RESULTS: Using Cox proportional hazard models, we examined the association between baseline levels of sTNF-R1 and sTNF-R2 with incident HF risk among 1285 participants of the Health, Aging, and Body Composition Study (age, 74.0±2.9 years; 51.4% women; 41.1% black). At baseline, median (interquartile range) of TNF, sTNF-R1, and sTNF-R2 levels was 3.14 (2.42-4.06), 1.46 (1.25-1.76), and 3.43 (2.95-4.02) ng/mL, respectively. During a median follow-up of 11.4 (6.9-11.7) years, 233 (18.1%) participants developed HF. In models controlling for other HF risk factors, TNF (hazard ratio [HR], 1.28; 95% confidence interval [CI], 1.02-1.61 per log2 increase) and sTNF-R1 (HR, 1.68; 95% CI, 1.15-2.46 per log2 increase), but not sTNF-R2 (HR, 1.15; 95% CI, 0.80-1.63 per log2 increase), were associated with a higher risk for HF. These associations were consistent across whites and blacks (TNF, sTNF-R1, sTNF-R2; interaction P=0.531, 0.091, and 0.795, respectively) and in both sexes (TNF, sTNF-R1, sTNF-R2; interaction P=0.491, 0.672, and 0.999, respectively). TNF-R1 was associated with a higher risk for HF with preserved versus reduced ejection fraction (HR, 1.81; 95% CI, 1.03-3.18; P=0.038 for preserved versus HR, 0.90; 95% CI, 0.56-1.44; P=0.667 for reduced ejection fraction; interaction P=0.05). CONCLUSIONS: In older adults, elevated levels of sTNF-R1 are associated with increased risk for incident HF. However, addition of TNF-R1 to the previously validated Health ABC HF risk model did not demonstrate material improvement in net discrimination or reclassification.

Incident heart failure in relation to vascular disease: insights from the Health, Aging, and Body Composition Study.

AIMS: The contribution of heart failure (HF) unrelated to vascular disease to the overall HF burden in older adults is not well characterized. This was investigated in this study. METHODS AND RESULTS: We assessed HF incidence and outcomes in 2895 participants of the Health ABC Study (age 74 ± 3 years, 48.4% men, 41.4% black) in relation to vascular disease (coronary, peripheral, or cerebrovascular disease) either present at baseline or developed prior to HF. During 11.4 years follow-up, 493 participants developed HF; 134 (27.2%) in participants without any prior vascular disease and 177 (36.8%) without coronary disease. Both baseline [hazard ratio (HR) 2.4, 95% confidence interval (CI) 1.9-2.8] and incident vascular disease (HR 4.3, 95% CI 3.6-5.2) were associated with HF. During a median follow-up of 2.1 years after HF onset, 67.5% participants died. Annual mortality after HF development was 21.3% in those with compared with 24.6% in those without vascular disease (HR 1.11, 95% CI 0.87-1.43; P = 0.399). There were 658 all-cause (436.3/1000 person-years) and 523 HF-related (346.4/1000 person-years) hospitalizations after HF development. There was no significant difference in hospitalizations between those with and without vascular disease [rate ratio (RR) 1.04, 95% CI 0.86-1.24 for all-cause, and RR 0.84 95% CI 0.69-1.02 for HF hospitalization]. HF with preserved EF was more common in participants without vascular disease (67.0% vs. 55.0%, P = 0.040). CONCLUSION: A significant proportion of HF in older adults develops without prior vascular disease. Outcomes for these patients are poor compared with those with preceding vascular disease. These data suggest the need for more targeted HF prediction and prevention efforts.

Developing therapies for heart failure with preserved ejection fraction: current state and future directions.

The burden of heart failure with preserved ejection fraction (HFpEF) is considerable and is projected to worsen. To date, there are no approved therapies available for reducing mortality or hospitalizations for these patients. The pathophysiology of HFpEF is complex and includes alterations in cardiac structure and function, systemic and pulmonary vascular abnormalities, end-organ involvement, and comorbidities. There remain major gaps in our understanding of HFpEF pathophysiology. To facilitate a discussion of how to proceed effectively in future with development of therapies for HFpEF, a meeting was facilitated by the Food and Drug Administration and included representatives from academia, industry, and regulatory agencies. This document summarizes the proceedings from this meeting.

Nitrate therapy for heart failure: benefits and strategies to overcome tolerance.

Combination therapy with hydralazine and nitrates can improve outcomes in patients with heart failure and low ejection fraction. However, this combination is underused in clinical practice for several reasons, including side effects related to hydralazine and polypharmacy. Some of the benefits seen with hydralazine, including afterload reduction and attenuation of nitrate tolerance, have also been observed with angiotensin-converting enzyme inhibitors. Demonstrating similar clinical benefits with nitrates plus angiotensin-converting enzyme inhibitor therapy alone, in the absence of hydralazine, may represent an opportunity to improve heart failure care by increasing the use of nitrates. In this paper, we summarize data that support studying such an approach.

Patient-reported selective adherence to heart failure self-care recommendations: a prospective cohort study: the Atlanta Cardiomyopathy Consortium.

Simultaneous adherence with multiple self-care instructions among heart failure (HF) patients is not well described. Patient-reported adherence to 8 recommendations related to exercise, alcohol, medications, smoking, diet, weight, and symptoms was assessed among 308 HF patients using the Medical Outcomes Study Specific Adherence Scale questionnaire (0="never" to 5="always," maximum score=40). A baseline cumulative score of ≥32/40 (average ≥80%) defined good adherence. Clinical events (death/transplantation/ventricular assist device), resource utilization, functional capacity (6-minute walk distance), and health status (Kansas City Cardiomyopathy Questionnaire [KCCQ]) were compared among patients with and without good adherence. The mean follow-up was 2.0±1.0 years, and adherence ranged from 26.3% (exercise) to 89.9% (medications). A cumulative score indicating good adherence was reported by 35.7%, whereas good adherence with every behavior was reported by 9.1% of patients. Good adherence was associated with fewer hospitalizations (all-cause 87.8 vs 107.6; P=.018; HF 29.6 vs 43.8; P=.007) and hospitalized days (all-cause 422 vs 465; P=.015; HF 228 vs 282; P<.001) per 100-person-years and better health status (KCCQ overall score 70.1±24.6 vs 63.8±22.8; P=.011). Adherence was not associated with clinical events or functional capacity. Patient-reported adherence with HF self-care recommendations is alarmingly low and selective. Good adherence was associated with lower resource utilization and better health status.

Reassessing the use of vasodilators in heart failure.

Heart failure is a growing epidemic that currently affects nearly 6 million people in the USA. Despite the well-documented hemodynamic abnormalities associated with the disease (e.g., elevated systemic vascular resistance), therapies that directly target these derangements have consistently failed to improve important clinical outcomes, unless they also act on the underlying pathophysiology of the disease (e.g., angiotensin-converting enzyme inhibitors). Numerous clinical trials of vasodilators in the treatment of heart failure have resulted in either neutral or negative outcomes suggesting that systemic vascular resistance may be an inappropriate target of therapy. The reasons for failure in these studies are manifold, including a poor understanding of vasodilator agents and their secondary effects, poorly designed studies that include a markedly heterogeneous patient population and a paucity of objective end points that may be used as targets of therapy, to name a few. Future studies of vasodilators will need to consider these issues in trial design.

Endothelial dysfunction, arterial stiffness, and heart failure.

Outcomes for heart failure (HF) patients remain suboptimal. No known therapy improves mortality in acute HF and HF with preserved ejection fraction; the most recent HF trial results have been negative or neutral. Improvement in surrogate markers has not necessarily translated into better outcomes. To translate breakthroughs with potential therapies into clinical benefit, a better understanding of the pathophysiology establishing the foundation of benefit is necessary. Vascular function plays a central role in the development and progression of HF. Endothelial function and nitric oxide availability affect myocardial function, systemic and pulmonary hemodynamics, and coronary and renal circulation. Arterial stiffness modulates ventricular loading conditions and diastolic function, key components of HF with preserved ejection. Endothelial function and arterial stiffness may therefore serve as important physiological targets for new HF therapies and facilitate patient selection for improved application of existing agents.