Heart failure is an increasing societal burden with greater than 5 million Americans affected. Acute decompensated heart failure (ADHF) is the leading cause of hospitalization in patients over the age of 65. In conjunction, there are greater than 1 million hospitalizations occurring annually for ADHF. Heart failure hospitalizations are strong predictors of subsequent mortality and carry a high risk for future readmission of approximately 25% at 30 days and 50 % at 6 months.¹

Various processes intersect when a patient transitions from chronic heart failure (CHF) to ADHF, including neurohormonal activation, up-regulation of inflammatory mediators, and cardiorenal interactions, which may be consequences of or occur in concert with deterioration of other comorbidities, such as coronary artery disease, new or worsening arrhythmias, and hypertension. These pathways lead to an elevation in ventricular filling pressures and signs of congestion. Worsening symptoms of congestion account for the majority of admissions for heart failure; however, these signs have poor sensitivity for detecting acute decompensation and are rather late manifestations reflecting significantly elevated intracardiac filling pressures.² Studies have demonstrated that increases in intra-cardiac and pulmonary artery pressures can precede the development of worsening signs and symptoms of congestion by weeks and can increase independent of changes in weight.³

Given the limited sensitivity of signs and symptoms of congestion, studies evaluating the efficacy of telemonitoring have failed to show a benefit in reducing heart failure readmissions.⁴

Various surrogates of intracardiac pressure and volume have been studied in an attempt to predict and prevent decompensated heart failure. The use of impedance monitoring, whether via noninvasive impedance cardiography or intracardiac impedance sensors in cardiac implantable electronic devices have been shown to predict heart failure admissions.⁵ However, incorporating intracardiac impedance sensors into a management strategy for CHF has not been shown to reduce hospitalizations.⁶

Early studies of implantable continuous hemodynamic monitors to guide management in heart failure did not demonstrate a reduction in heart failure hospitalizations. The CardioMEMS Heart Sensor Allows Monitoring of Pressure to Improve Outcomes in NYHA Class III Heart Failure Patients (CHAMPION) trial⁷ was a prospective, single-blind, multicenter trial that randomized patients with New York Heart Association Class III heart failure with a previous admission for heart failure in the prior year, regardless of left ventricular ejection fraction, to management with a wireless implantable hemodynamic monitoring system or a control group for 6 months. The primary efficacy endpoint was the rate of heart failure-related hospitalizations at 6 months. All patients had the wireless radiofrequency sensor implanted in the pulmonary artery, but the treatment group allowed the clinician to access the pulmonary artery pressure readings. In the treatment group, clinicians had access to the pulmonary artery pressure data at least once per week, with patients uploading measurements daily. If pulmonary artery pressures were elevated, the protocol-defined treatment goal was to lower pulmonary artery pressures using either diuretics, vasodilators and/or neurohormonal blockade heart failure therapies.

At 6 months, there was a 28% reduction in heart failure hospitalizations, with 84 hospitalizations in the treatment group, compared to 120 in the control group (hazard ratio [HR] 0.72, 95% confidence interval [CI] 0.60-0.85, p = 0.0002). There was a 37% reduction in heart failure-related hospitalizations in the treatment group during the entire follow-up period, which averaged 15 months (HR 0.63, 95% CI 0.52-0.77, p < 0.0001). Further, there was a significant improvement in quality of life in the treatment group, as assessed by improvement in Minnesota Living with Heart Failure Questionnaire. Not surprisingly, the length of stay for heart failure-related hospitalizations was significantly shorter in the treatment group, as compared to the control group (2.2 days vs. 3.8 days, p = 0.02) and the treatment group had more changes to heart failure medications compared to the control group (9.1 per patient versus 3.8, p <0.0001). The rate of device related or system related complications was low (n = 8) with 98.6% freedom from complications.

There have not been many effective treatment options that have been shown to improve outcomes in patients with heart failure with preserved ejection fraction. Approximately 20% of the patients enrolled in the CHAMPION trial had heart failure with preserved ejection fraction defined as heart failure with a left ventricular ejection fraction of ≥ 40%. In this pre-specified subgroup of patients, heart failure hospitalizations were 46% lower in the treatment group compared to the control group by primarily adjusting diuretic therapy based on pulmonary artery pressure tracings (incidence rate ratio 0.54; 95% CI 0.38-0.70; p < 0.0001).⁸

The results of the CHAMPION trial suggest that hemodynamic-guided medical management of heart failure patients via an invasive wireless implantable heart monitor can improve symptoms and reduce heart failure hospitalizations by approximately one-third. It must be emphasized that these pressure monitoring tools were used to implement a protocol-defined medical strategy that involved a team-based approach to care coordination and delivery. In addition to frequent clinic visits, there was online access to review pulmonary pressures daily, and an automatic email notification system was in place to notify study personnel if the daily pulmonary pressures were outside of the user-defined range. The protocol considered patients with elevated pulmonary pressures to be volume overloaded with the initial recommendation to increase diuretic therapy. If pulmonary pressures remained persistently elevated despite optimal diuretic medication changes, vasodilator therapy was recommended. The majority of medication adjustments were around diuretic therapy. The below-average rate of heart failure hospitalizations observed in the control group highlighted the importance of CHF management.

While the results of this trial are impressive, it must be noted that highly trained heart failure physicians and mid-level providers cared for the patients. In practice, the "virtual heart failure clinic" created in this trial is not easily replicated outside of dedicated heart failure centers or well-staffed, hospital-based programs. In addition, little is revealed in the CHAMPION trial on potential side effects of aggressive diuresis or vasodilation that were used to reduce pulmonary artery pressures. This may be particularly relevant as this therapeutic strategy is applied to a large real-world cohort of elderly patients with heart failure. It is also unclear how this strategy applies to patients with more (or less) severe forms of heart failure because the trial only included patients with Class III symptoms.

At our center, we began using the CardioMEMS device a year ago. While we have been able to demonstrate significant benefit in some patients, there is a data burden that we initially were not prepared to handle. It is important to think about the resources that are needed to handle the data and increased communication with patients prior to initiation of the program. The success of a CardioMEMS program is predicated on developing a robust virtual heart failure program as was done in the CHAMPION trial.

References

1. Dharmarajan K, Hsieh AF, Lin Z et al. Diagnoses and timing of 30-day readmissions after hospitalization for heart failure, acute myocardial infarction, or pneumonia. JAMA 2013;309:355-63.
2. Stevenson LW, Perloff JK. The limited reliability of physical signs for estimating hemodynamics in chronic heart failure. JAMA 1989;261:884-888.
3. Ritzema J, Troughton R, Melton I, et al. Physician-directed patient self-management of left atrial pressure in advanced chronic heart failure. Circulation 2010;121:1086-95.
4. Chaudhry SI, Mattera JA, Curtis JP, et al. Telemonitoring in patients with heart failure. N Engl J Med 2010;363:2301-9.
5. Whellan DJ, Ousdigian KT, Al-Khatib SM, et al. Combined heart failure device diagnostics identify patients at higher risk of subsequent heart failure hospitalizations: results from PARTNERS HF (Program to Access and Review Trending Information and Evaluate Correlation to Symptoms in Patients With Heart Failure) study. J Am Coll Cardiol 2010;55:1803-10.
6. Van Veldhuisen DJ, Braunschweigh F, Conraads V, et al. Intrathoracic impedance monitoring, audible patient alerts, and outcome in patients with heart failure. Circulation 2011;124:1719-26.
7. Abraham WT, Adamson PB, Bourge RC, et al. Wireless pulmonary artery haemodynamic monitoring in chronic heart failure: a randomised controlled trial. Lancet 2011;377:658-66.
8. Adamson PB, Abraham WT, Bourge RC, et al. Wireless pulmonary artery pressure monitoring guides management to reduce decompensation in heart failure with preserved ejection fraction. Circ Heart Fail 2014;7:935-44.

Keywords: Aged, Ambulatory Care, Arrhythmias, Cardiac, Cardiography, Impedance, Comorbidity, Confidence Intervals, Control Groups, Coronary Artery Disease, Diuresis, Diuretics, Electric Impedance, Follow-Up Studies, Heart Failure, Hospitalization, Hypertension, Inflammation Mediators, Patient Readmission, Patient Transfer, Prospective Studies, Pulmonary Artery, Quality of Life, Single-Blind Method, Stroke Volume, Treatment Outcome, Up-Regulation, Vasodilation, Vasodilator Agents, Ventricular Pressure

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