Elsevier

The Lancet

Volume 377, Issue 9766, 19–25 February 2011, Pages 658-666
The Lancet

Articles
Wireless pulmonary artery haemodynamic monitoring in chronic heart failure: a randomised controlled trial

https://doi.org/10.1016/S0140-6736(11)60101-3Get rights and content

Summary

Background

Results of previous studies support the hypothesis that implantable haemodynamic monitoring systems might reduce rates of hospitalisation in patients with heart failure. We undertook a single-blind trial to assess this approach.

Methods

Patients with New York Heart Association (NYHA) class III heart failure, irrespective of the left ventricular ejection fraction, and a previous hospital admission for heart failure were enrolled in 64 centres in the USA. They were randomly assigned by use of a centralised electronic system to management with a wireless implantable haemodynamic monitoring (W-IHM) system (treatment group) or to a control group for at least 6 months. Only patients were masked to their assignment group. In the treatment group, clinicians used daily measurement of pulmonary artery pressures in addition to standard of care versus standard of care alone in the control group. The primary efficacy endpoint was the rate of heart-failure-related hospitalisations at 6 months. The safety endpoints assessed at 6 months were freedom from device-related or system-related complications (DSRC) and freedom from pressure-sensor failures. All analyses were by intention to treat. This trial is registered with ClinicalTrials.gov, number NCT00531661.

Findings

In 6 months, 84 heart-failure-related hospitalisations were reported in the treatment group (n=270) compared with 120 in the control group (n=280; rate 0·32 vs 0·44, hazard ratio [HR] 0·72, 95% CI 0·60–0·85, p=0·0002). During the entire follow-up (mean 15 months [SD 7]), the treatment group had a 37% reduction in heart-failure-related hospitalisation compared with the control group (158 vs 254, HR 0·63, 95% CI 0·52–0·77; p<0·0001). Eight patients had DSRC and overall freedom from DSRC was 98·6% (97·3–99·4) compared with a prespecified performance criterion of 80% (p<0·0001); and overall freedom from pressure-sensor failures was 100% (99·3–100·0).

Interpretation

Our results are consistent with, and extend, previous findings by definitively showing a significant and large reduction in hospitalisation for patients with NYHA class III heart failure who were managed with a wireless implantable haemodynamic monitoring system. The addition of information about pulmonary artery pressure to clinical signs and symptoms allows for improved heart failure management.

Funding

CardioMEMS.

Introduction

Despite current treatments, rates of hospital admissions for heart failure have improved little during the past three decades.1 In the USA, between 1996 and 2006, hospital discharges for heart failure rose from 877 000 to 1 106 000.2 Among beneficiaries of Medicare, 27% of discharged patients with heart failure were readmitted to hospital within 30 days.3 More than half the US$39·2 billion yearly direct cost of care for heart failure in the USA is attributable to the cost of treatment in hospital.2 The estimated average cost of the final 2 years of life for patients with heart failure is greater than $156 000, with more than 75% attributable to hospital admission for heart failure during the last 6 months of life.4 Improvements in outpatient management of patients with chronic heart failure are needed to address the increasing burden of worsening heart failure that requires admission to hospital.

Patients are usually admitted to hospital for heart failure because of worsening signs and symptoms of congestion.5 Previous investigations have shown that increases in intracardiac and pulmonary artery pressures are the cause of this clinical congestion and are apparent several days to weeks before the onset of worsening signs, symptoms, and hospital admission,6, 7 suggesting that early intervention targeting these pressures might reduce the risk of admission to hospital. In a clinical trial,8 increases in intracardiac pressures often arose independently of weight changes, such that monitoring of weight alone was inadequate to identify congestion in time to avert the events associated with heart failure. This finding might account for why telemonitoring systems that rely on patient-reported assessment of general health, symptoms of heart failure, and daily weight change have not reduced readmission or mortality rates.9

Implantable systems for chronic monitoring of intracardiac and pulmonary artery pressures have been developed.10, 11, 12, 13, 14, 15 Preliminary findings with the use of these systems suggest a reduction in hospital admissions for heart failure. The hypothesis in the present study, the CardioMEMS Heart Sensor Allows Monitoring of Pressure to Improve Outcomes in NYHA Class III Heart Failure Patients (CHAMPION) trial, was that management of heart failure by use of pulmonary artery pressures would greatly reduce the rate of heart-failure-related hospitalisation.

Section snippets

Patients

Patients (aged ≥18 years) were eligible for participation in the CHAMPION study if they had moderate (New York Heart Association [NYHA] functional class III) heart failure for at least 3 months, irrespective of left ventricular ejection fraction or cause, and a hospitalisation for heart failure within the past 12 months. Patients had to be given drug and device treatments for heart failure at optimum or best-tolerated stable doses, according to national guidelines.16 Exclusion criteria included

Results

Between Sept 6, 2007, and Oct 7, 2009, 550 patients were randomly assigned to the treatment (n=270) and control groups (n=280). Figure 2 shows the trial profile. All patients remained in their assigned group until the last patient completed 6 months of follow-up. The mean follow-up was 15 months (SD 7, total duration 250 176 patient days). The groups were similar with respect to baseline characteristics (table 1). All analyses were undertaken on patients in their original assignment groups.

Both

Discussion

W-IHM is safe and significantly reduces the risk of heart-failure-related hospitalisation in patients with NYHA functional class III heart failure. The 6-month risk of heart-failure-related hospital admission was 30% lower in the W-IHM group, managed with daily measurement of pulmonary artery pressures plus standard of care, than in the control group, managed according to standard-of-care monitoring of heart failure alone. This reduction in risk lasted the entire period of the randomised

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