Treatment with inotropic agents is one of the most controversial topics in heart failure. Initial enthusiasm, based on strong pathophysiological rationale and apparent empirical efficacy, has been progressively limited by results of controlled trials and registries showing poorer outcomes of the patients on inotropic therapy. The use of these agents remains, however, potentially indicated in a significant proportion of patients with low cardiac output, peripheral hypoperfusion and end-organ dysfunction caused by heart failure. Limitations of inotropic therapy seem to be mainly related to their mechanisms of action entailing arrhythmogenesis, peripheral vasodilation, myocardial ischemia and damage, and possibly due to their use in patients without a clear indication, rather than to the general principle of inotropic therapy itself. This review will discuss the characteristics of the patients with a potential indication for inotropic therapy, the main data from registries and controlled trials, the mechanism of the untoward effects of these agents on outcomes and, lastly, perspectives with new agents with novel mechanisms of action.

Objectives

The study tested the hypothesis that augmentation of the left ventricular (LV) wall thickness with direct intramyocardial injections of alginate hydrogel implants (AHI) reduces LV cavity size, restores LV shape, and improves LV function in dogs with heart failure (HF).

Background

Progressive LV dysfunction, enlargement, and chamber sphericity are features of HF associated with increased mortality and morbidity.

Methods

Studies were performed in 14 dogs with HF produced by intracoronary microembolizations (LV ejection fraction [EF] <30%). Dogs were randomized to AHI treatment (n = 8) or to sham-operated control (n = 6). During an open-chest procedure, dogs received either intramyocardial injections of 0.25 to 0.35 ml of alginate hydrogel (Algisyl-LVR, LoneStar Heart, Inc., Laguna Hills, California) or saline. Seven injections were made ∼ 1.0 to 1.5 cm apart (total volume 1.8 to 2.1 ml) along the circumference of the LV free wall halfway between the apex and base starting from the anteroseptal groove and ending at the posteroseptal groove. Hemodynamic and ventriculographic measurements were made before treatment (PRE) and repeated post-surgery for up to 17 weeks (POST).

Results

Compared to control, AHI significantly reduced LV end-diastolic and end-systolic volumes and improved LV sphericity. AHI treatment significantly increased EF (26 ± 0.4% at PRE to 31 ± 0.4% at POST; p < 0.05) compared to the decreased EF seen in control dogs (27 ± 0.3% at PRE to 24 ± 1.3% at POST; p < 0.05). AHI treatment was well tolerated and was not associated with increased LV diastolic stiffness.

Conclusions

In HF dogs, circumferential augmentation of LV wall thickness with AHI improves LV structure and function. The results support continued development of AHI for the treatment of patients with advanced HF.

AIMS: AUGMENT-HF was an international, multi-centre, prospective, randomized, controlled trial to evaluate the benefits and safety of a novel method of left ventricular (LV) modification with alginate-hydrogel. METHODS: Alginate-hydrogel is an inert permanent implant that is directly injected into LV heart muscle and serves as a prosthetic scaffold to modify the shape and size of the dilated LV. Patients with advanced chronic heart failure (HF) were randomized (1 : 1) to alginate-hydrogel (n = 40) in combination with standard medical therapy or standard medical therapy alone (Control, n = 38). The primary endpoint of AUGMENT-HF was the change in peak VO2 from baseline to 6 months. Secondary endpoints included changes in 6-min walk test (6MWT) distance and New York Heart Association (NYHA) functional class, as well as assessments of procedural safety. RESULTS: Enrolled patients were 63 ± 10 years old, 74% in NYHA functional class III, had a LV ejection fraction of 26 ± 5% and a mean peak VO2 of 12.2 ± 1.8 mL/kg/min. Thirty-five patients were successfully treated with alginate-hydrogel injections through a limited left thoracotomy approach without device-related complications; the 30-day surgical mortality was 8.6% (3 deaths). Alginate-hydrogel treatment was associated with improved peak VO2 at 6 months-treatment effect vs. CONTROL: +1.24 mL/kg/min (95% confidence interval 0.26-2.23, P = 0.014). Also 6MWT distance and NYHA functional class improved in alginate-hydrogel-treated patients vs. Control (both P < 0.001). CONCLUSION: Alginate-hydrogel in addition to standard medical therapy for patients with advanced chronic HF was more effective than standard medical therapy alone for improving exercise capacity and symptoms. The results of AUGMENT-HF provide proof of concept for a pivotal trial. TRIAL REGISTRATION NUMBER: NCT01311791.

There are over 1 million hospitalizations for heart failure (HF) annually in the United States alone, and a similar number has been reported in Europe. Recent clinical trials investigating novel therapies in patients with hospitalized HF (HHF) have been negative, and the post-discharge event rate remains unacceptably high. The lack of success with HHF trials stem from problems with understanding the study drug, matching the drug to the appropriate HF subgroup, and study execution. Related to the concept of study execution is the importance of including appropriate study sites in HHF trials. Often overlooked issues include consideration of the geographic region and the number of patients enrolled at each study center. Marked differences in baseline patient co-morbidities, serum biomarkers, treatment utilization and outcomes have been demonstrated across geographic regions. Furthermore, patients from sites with low recruitment may have worse outcomes compared to sites with higher enrollment patterns. Consequently, sites with poor trial enrollment may influence key patient end points and likely do not justify the costs of site training and maintenance. Accordingly, there is an unmet need to develop strategies to identify the right study sites that have acceptable patient quantity and quality. Potential approaches include, but are not limited to, establishing a pre-trial registry, developing site performance metrics, identifying a local regionally involved leader and bolstering recruitment incentives. This manuscript summarizes the roundtable discussion hosted by the Food and Drug Administration between members of academia, the National Institutes of Health, industry partners, contract research organizations and academic research organizations on the importance of selecting optimal sites for successful trials in HHF.

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.

The increasing burden and the continued suboptimal outcomes for patients with heart failure underlines the importance of continued research to develop novel therapeutics for this disorder. This can only be accomplished with successful translation of basic science discoveries into direct human application through effective clinical trial design and execution that results in a substantially improved clinical course and outcomes. In this respect, phase II clinical trials play a pivotal role in determining which of the multitude of potential basic science discoveries should move to the large and expansive registration trials in humans. A critical examination of the phase II trials in heart failure reveals multiple shortcomings in their concept, design, execution, and interpretation. To further a dialogue on the challenges and potential for improvement and the role of phase II trials in patients with heart failure, the Food and Drug Administration facilitated a meeting on October 17, 2016, represented by clinicians, researchers, industry members, and regulators. This document summarizes the discussion from this meeting and provides key recommendations for future directions.