Plasma norepinephrine and atrial natriuretic peptide in heart failure: influence of felodipine in the third Vasodilator Heart Failure Trial. V-HeFT III investigators

Exploration of alive-and-ventilator free days as an outcome measure for clinical trials of Resuscitative interventions

BACKGROUND

Outcome selection is a critically important aspect of clinical trial design. Alive-and-ventilator free days is an outcome measure commonly used in critical care clinical trials, but has not been fully explored in resuscitation science.

METHODS

A simulation study was performed to explore approaches to the definition and analysis of alive-and-ventilator free days in cardiac arrest populations. Data from an in-hospital cardiac arrest observational cohort and from the Pragmatic Airway Resuscitation Trial were used to inform and conduct the simulations and validate approaches to alive-and-ventilator free days measurement and analysis.

FINDINGS

Alive-and-ventilator-free days is a flexible outcome measure in cardiac arrest populations. An approach to alive-and-ventilator free days that assigns -1 days when return of spontaneous circulation is not achieved provides a wider distribution of the outcome and improves statistical power. The optimal approach to the analysis of alive-and-ventilator free days varies based on the expected impact of the intervention under study on rates of return of spontaneous circulation, survival, and ventilator-free survival.

CONCLUSIONS

Alive-and-ventilator free days adds to the armamentarium of clinical trialists in the field of resuscitation science.

Natriuretic Peptides as Biomarkers of Treatment Response in Clinical Trials of Heart Failure

OBJECTIVES

This study sought to determine whether treatment-related changes in natriuretic peptides (NPs) predict longer-term therapeutic effects in clinical trials of heart failure (HF).

BACKGROUND

The lack of reliable predictors of efficacy of drugs and devices in HF has presented a major hurdle to the development and evaluation of novel therapies.

METHODS

The study conducted a trial-level analysis of 16 phase III chronic HF trials completed between 1987 and 2013 studying 18 therapeutic comparisons in 48,844 patients. Weighted Pearson correlation coefficients were calculated between average control- or placebo-corrected changes in NPs and longer-term treatment effects on clinical endpoints (expressed as log-transformed hazard ratios).

RESULTS

Median follow-up for clinical endpoints was 28 (25th to 75th percentile range: 18 to 36) months. NPs were available in a median of 748 (25th to 75th percentile range: 270 to 1,868) patients and measured at a median of 4 (25th to 75th percentile range: 3 to 6) months after randomization. Treatment-related changes in NPs were not correlated with longer-term treatment effects on all-cause mortality (r = 0.12; p = 0.63), but were correlated with HF hospitalization (r = 0.63; p = 0.008). Correlation with HF hospitalization improved when analyses were restricted to trials completed in the last decade (>2010; r = 0.92; p = 0.0095), using N-terminal pro-B-type NP assays (r = 0.65; p = 0.06), and evaluating inhibitors of the renin-angiotensin-aldosterone system (r = 0.97; p = 0.0002).

CONCLUSIONS

When examining a broad range of interventions, therapy-related changes in NPs appeared modestly correlated with longer-term therapeutic effects on hospitalization for HF, but not with effects on all-cause mortality. These observations raise important caveats regarding the use of NPs in phase II trials for decision making regarding phase III trials.

What change in outcomes after cardiac arrest is necessary to change practice? Results of an international survey

BACKGROUND

Efficient trials of interventions for patients with out-of-hospital cardiac arrest (OHCA) should have adequate but not excess power to detect a difference in outcomes. The minimum clinically important difference (MCID) is the threshold value in outcomes observed in a trial at which providers should choose to adopt a treatment. There has been limited assessment of MCID for outcomes after OHCA. Therefore, we conducted an international survey of individuals interested in cardiac resuscitation to define the MCID for a range of outcomes after OHCA.

METHODS

A brief survey instrument was developed and modified by consensus. Included were open-ended responses. The survey included an illustrative example of a hypothetical randomized study with distributions of outcomes based on those in a public use datafile from a previous trial. Elicited information included the minimum significant difference required in an outcome to change clinical practice. The population of interest was emergency physicians or other practitioners of acute cardiovascular research.

RESULTS

Usable responses were obtained from 160 respondents (50% of surveyed) in 46 countries (79% of surveyed). MCIDs tended to increase as baseline outcomes increased. For a population of patients with 25% survival to discharge and 20% favorable neurologic status at discharge, the MCID were median 5 (interquartile range [IQR] 3, 10) percent for survival to discharge; median 5 (IQR 2, 10) percent for favorable neurologic status at discharge, median 4 (IQR 2, 9) days of ICU-free survival and median 4 (IQR 2, 8) days of hospital-free survival.

CONCLUSION

Reported MCIDs for outcomes after OHCA vary according to the outcome considered as well as the baseline rate of achieving it. MCIDs of ICU-free survival or hospital-free survival may be useful to accelerate the rate of evidence-based change in resuscitation care.

The effects of medications on circulating levels of cardiac natriuretic peptides

Circulating cardiac natriuretic peptide levels are being used increasingly in a range of clinical circumstances. Since it is evident that drugs used in the treatment of cardiovascular disorders can modulate natriuretic peptide levels, we here review the literature documenting these effects. Diuretics, blockers of the renin-angiotensin system, vasodilator agents, dopamine-like agonists, amiodarone, and perhaps allopurinol and statins suppress natriuretic peptide levels, most obviously in heart failure. Beta-blockers stimulate natriuretic peptide concentrations in hypertensive subjects, whereas in heart failure they have little effect or are stimulatory in the short term and inhibitory with sustained therapy. Digitalis compounds and aspirin tend to increase natriuretic peptide levels, and calcium channel blocking agents have varying effects depending on the individual drug and duration of administration. The effects of other drugs are less clear. Additional information is needed regarding the effects of medications along with dissection of the role of altered cardiac secretion versus changes in plasma clearance as explanation for drug-induced perturbations in natriuretic peptide concentrations. In the meantime, clinicians need to consider the known effects of medications when interpreting plasma levels of the cardiac natriuretic peptides.

The influence of sex on right ventricular dysfunction in patients with severely depressed left ventricular ejection fraction

AIM

To assess the influence of sex on right ventricular dysfunction (RVD) in patients with severe left ventricular systolic dysfunction.

METHODS AND RESULTS

We studied 385 consecutive patients with left ventricular ejection fraction (LVEF) <0.35. All patients underwent invasive measurement of right ventricular and pulmonary artery pressures and evaluation of RVD by standard transthoracic echocardiography. Female patients (n=84, 21.8%) were significantly older than male patients (62.0+/-11.4 vs. 58.2+/-10.7 years), p=0.005. The prevalence of RVD was lower in women (26.5%) than in men (38.9%), p=0.03; both in patients with and without coronary artery disease (19.4% vs. 34.5% and 31.9% vs. 44.4%, respectively). Haemodynamic parameters and LVEF were similar in men and women. Low LVEF, pulmonary systolic pressure, degree of mitral regurgitation, male sex, and absence of significant coronary artery disease were independently correlated with RVD.

CONCLUSION

Women with severe left ventricular systolic dysfunction have less RVD than men, despite similar haemodynamic parameters and LVEF.

Effects of low-dose treatment with felodipine versus fosinopril in Chinese patients with nonischemic heart failure and normal blood pressure: A double-blind, randomized, crossover study

BACKGROUND

Two second-generation calcium channel blockers, felodipine and amlodipine besylate, have been associated with similar high mortality rates in patients with ischemic heart failure (HF) but not in patients with nonischemic causes of HF. In patients with nonischemic HF, amlodipine might have a beneficial effect on survival. However, no difference in mortality rates was found between felodipine and placebo in a nonischemic HF group. Felodipine 10 mg/d was used in 1 large study, a dose considered high for nonischemic HF usually associated with normal blood pressure (BP).

OBJECTIVE

The aim of this study was to compare the effects of 12-week, low-dose treatment with felodipine versus those of an angiotensin-converting enzyme inhibitor, fosinopril sodium, in patients with nonischemic HF and normal BP.

METHODS

This double-blind, randomized, crossover trial was conducted at Taipei Medical University Hospital (Taipei, Taiwan). Patients aged ≥ 18 years with angiographically proved, nonischemic HF and normal BP who were being treated with an optimal regimen of digitalis and diuretics were enrolled. After a 2-week run-in period, patients were randomized to first receive 12 weeks of treatment with felodipine tablets (2.5 mg/d) or fosinopril tablets (7.5 mg/d) and, after a 2-week washout period, were crossed over to the opposite treatment. Efficacy analysis was performed before (baseline) and after treatment and included symptomatic assessment using a 7-grade clinical scale; 2-dimensional echocardiography (2-D echo); exercise tests; and neurohumoral data, including plasma renin activity, plasma aldosterone, and 24-hour urinary epinephrine (E) and norepinephrine (NE) measurements. The primary end point was death due to HF, and the secondary end point was hospital admission due to worsening HF. Compliance was measured using a pill count at the end of each treatment period.

RESULTS

We enrolled 33 patients. One developed worsening HF during the run-in period and was admitted. A total of 32 patients entered the study (18 men, 14 women; mean [SD] age, 48.2 [6.3] years [range, 34-56 years]; mean [SD] systolic BP, 117.2 [9.8] mm Hg [range, 100-138 mm Hg]; mean [SD] diastolic BP, 59.4 [5.7] mm Hg [range, 50-72 mm Hg]). No hospital admission or cardiac death due to HF occurred during 12 weeks of treatment. Twenty-seven patients were included in the felodipine assessment, and 30 patients were included in the fosinopril assessment. Significant improvement in clinical score was noted in both treatment groups (both P < 0.01). The clinical scores did not differ significantly between the 2 treatments. No significant differences were found in 2-D echo parameters between treatments or within groups after treatment versus baseline. Significant improvement in exercise duration was noted with both study drugs after treatment versus baseline (both P < 0.01). No significant difference in exercise duration was found between the 2 treatments. Urinary E and NE were not significantly different between treatments or after treatment with either study drug compared with baseline.

CONCLUSION

The present findings suggest that, in Chinese patients with moderate to severe HF who have normal BP and insignificant coronary artery disease and were being treated with diuretics and digitalis, a 12-week, low-dose course of felodipine (2.5 mg/d) as a vasodilator was associated with as satisfactory an outcome as standard treatment with fosinopril (7.5 mg/d).