Pulmonary hypertension
Continuous Hemodynamic Monitoring in Patients With Pulmonary Arterial Hypertension

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Background

The purpose of this study was to determine whether an implantable hemodynamic monitor (IHM) could be used to judge the response of pulmonary arterial hypertension (PAH) patients to changes in therapy.

Methods

A prospective, non-randomized, multi-center study evaluated physical examination, functional class, echocardiography, brain natriuretic peptide (BNP) levels, exercise capacity assessed by 6-minute walk and cardiopulmonary exercise tests, and quality of life at baseline and at 12 weeks. IHM measurements were continuously available to clinicians between clinic visits. Based on a priori, pre-specified analyses, the relationships between hemodynamic values, PAH treatments and clinical parameters were tracked in an observational fashion.

Results

Twenty-four PAH patients underwent IHM implantation prior to a change in PAH therapy. IHM data identified 13 of the 15 patients who improved their 6-minute walk distance by >30 m at 12 weeks (+48 ± 65 m, p < 0.05), whereas the others walked less (−78 ± 115 m, not statistically significant). In addition, peak Vo2, BNP levels and Minnesota Living with Heart Failure Questionnaire scores only improved in the former group. The change in mean pulmonary artery pressure correlated with the change in 6-minute walk distance at 12 weeks (r = −0.71, p < 0.001). Device-related adverse events were comparable to those known to occur with a pacemaker-like device.

Conclusions

Changes in ambulatory continuous hemodynamic measurements predicted changes in 6-minute walk distance after the start or addition of PAH therapy. The IHM also identified patients who had improved exercise tolerance, BNP levels and quality of life. The IHM appeared to be well tolerated and allowed rapid hemodynamic feedback between clinic visits.

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Patient Population

Patients with World Health Organization (WHO) Group I, Functional Class II or III with idiopathic PAH or PAH associated with connective tissue disease or anorexigens were enrolled in this study. Patients were either newly diagnosed or on stable PAH therapy for at least 3 months, but for whom additional PAH therapy was indicated. Additional screening study enrollment criteria were: (1) echocardiogram measurement consistent with PAH with an estimated RV systolic pressure >50 mm Hg; (2) no

Patient Population and Study Performance

Twenty-four patients with PAH were enrolled in the study and had an IHM implanted. Two patients were excluded from the subsequent data analysis; 1 patient did not require additional PAH-specific therapy and 1 patient died from right heart failure before obtaining the prescribed PAH therapy due to logistic reasons. Autopsy did not demonstrate any evidence of device-related complication. Patients' baseline characteristics are presented in Table 1. Seventy-three percent of patients had idiopathic

Discussion

The 6-minute walk distance is a frequently used end-point in clinical PAH trials and has been shown to correlate with outcome23 in these patients. However, it is possible that long-term outcome in PAH will be best preserved by targeting hemodynamic improvements to reduce risk of subsequent right ventricular failure. Non-invasive assessments of cardiac morphology (RV size, LV eccentricity) and hemodynamics, including cardiac output by echocardiography, may also prove to be useful parameters to

References (27)

Cited by (28)

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    2016, Clinical Cardiac Pacing, Defibrillation and Resynchronization Therapy
  • Novel technologies and devices for monitoring and treating pulmonary arterial hypertension

    2015, Canadian Journal of Cardiology
    Citation Excerpt :

    In a small study by Kjellstrom et al., implantation of the CardioMEMS (St Jude Medical, Atlanta, GA) device in 10 patients with PAH allowed for closer monitoring of response to initiation of therapy and ambulatory monitoring with activity.27 Frantz and colleagues also explored the use of the Chronicle device (Medtronic, Minneapolis, MN) in a prospective, nonrandomized, multicentre study in 24 patients with PAH and correlated changes in hemodynamics with quality of life, changes in 6-minute walk distance, exercise tolerance, and brain natriuretic peptide.28 In an innovative study performed by Fruhwald et al., the Chronicle device was implanted in 5 patients with WHO Group 1 PAH and repeated short-term tests were performed with inhalation of iloprost, which demonstrated only short-term improvement in pulmonary hemodynamics.29

  • Hemodynamic ranges during daily activities and exercise testing in patients with pulmonary arterial hypertension

    2014, Journal of Cardiac Failure
    Citation Excerpt :

    A pressure sensor lead was placed with the tip in the right ventricle, preferably in a middle to high septal position. The pressure monitoring system has been described in detail previously.9–12 Measurement of heart rate (HR), right ventricular systolic (RVSP), diastolic (RVDP), and mean pulmonary arterial (MPAP) pressure were derived from each cardiac cycle and stored continuously as the median over a preprogrammed storage interval.

  • Pericardial effusions in pulmonary arterial hypertension: Characteristics, prognosis, and role of drainage

    2013, Chest
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    Pericardiocentesis resulted in symptomatic and hemodynamic improvement in the setting of PAH in most patients. The latter was previously documented in a patient using an implantable hemodynamic device.24 The absence of acute right ventricular dilation or dysfunction was confirmed through dynamic echocardiographic imaging.

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Conflicts of interest: R.P.F., R.L.B., R.C.B., R.J.B. and M.D.M. have received research support from Medtronic, Inc. B.K. and T.D.B. are employees of Medtronic, Inc.

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