Chest
Volume 130, Issue 3, September 2006, Pages 841-846
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Original Research: Pulmonary Hypertension
Chronic Thromboembolic and Pulmonary Arterial Hypertension Share Acute Vasoreactivity Properties

https://doi.org/10.1378/chest.130.3.841Get rights and content

Background

Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are the major classes of pulmonary hypertensive disorders according to the World Health Organization; both lead to right heart failure and death. A better understanding of disease mechanisms has led to the suggestion that the thromboembolic and nonthromboembolic types of pulmonary hypertension may share pathophysiologic features. We therefore compared acute vasoreactivity and proximal pulmonary artery compliance in patients with PAH and CTEPH during the initial diagnostic heart catheterization.

Methods

Right heart catheterization using a flow-directed Swan-Ganz catheter was performed in patients with CTEPH (n = 22) and PAH (n = 35). Pulmonary hemodynamics were assessed at baseline, during the inhalation of 40 ppm of nitric oxide, and 30 min after the inhalation of 10 μg of iloprost. To assess the proximal pulmonary artery compliance, the pulse pressure (PP) [systolic − diastolic pressure] and the fractional PP (PPf) [divided by the mean pressure] were calculated.

Results

Both vasodilators produced similar hemodynamic improvement, and the difference between CTEPH and PAH was not significant. The baseline PP and PPf did not vary between the two groups.

Conclusion

Patients with PAH and CTEPH show similar acute vasoreactivity to inhaled nitric oxide and iloprost, and have similar pulmonary artery compliance. These findings support the presence of some shared pathophysiologic pathways in both disorders and may lead to therapeutic implications in patients with inoperable CTEPH.

Section snippets

Patient Population

Thirty-five patients with PAH and 22 patients with CTEPH were included in the study after obtaining written informed consent. The study was approved by the local ethics committee. PAH was diagnosed as idiopathic (n = 25) if the evaluation performed before catheterization did not reveal any other causes of elevated pulmonary pressure and was associated with other conditions such as congenital heart disease (n = 6), connective tissue disease (n = 2), and HIV (n = 2) that were diagnosed by medical

Patient Characteristics

A total of 57 patients, 35 with PAH and 22 with CTEPH, were included in the study. Patient characteristics are presented in Table 1. Patients with CTEPH were on average older than those with PAH, and had lower CI, Sao2, and mixed venous saturation (S v¯o2). Other parameters did not vary significantly between the two groups.

Acute Vasoreactivity Testing

iNO and iILO significantly decreased MPAP and PVR in both PAH and CTEPH patients, and to a comparable extent. The response to iNO and iILO, as well as the response

DISCUSSION

We found that the inhalation of iNO and/or iILO during the initial diagnostic right heart catheterization decreased MPAP and increased CI in patients with CTEPH and PAH who were in WHO functional classes III to IV, with the magnitude of the response as well as the number of responders being not different between CTEPH and PAH patients. Patients with PAH and CTEPH also had similar indexes of proximal pulmonary arterial compliance. These results suggest that CTEPH and PAH may share some

REFERENCES (38)

  • V Fuster et al.

    Primary pulmonary hypertension: natural history and the importance of thrombosis

    Circulation

    (1984)
  • HI Palevsky et al.

    Primary pulmonary hypertension: vascular structure, morphometry, and responsiveness to vasodilator agents

    Circulation

    (1989)
  • V Castelain et al.

    Pulmonary artery pressure-flow relations after prostacyclin in primary pulmonary hypertension

    Am J Respir Crit Care Med

    (2002)
  • H Olschewski et al.

    Inhaled iloprost for severe pulmonary hypertension

    N Engl J Med

    (2002)
  • HA Ghofrani et al.

    Sildenafil for long-term treatment of nonoperable chronic thromboembolic pulmonary hypertension

    Am J Respir Crit Care Med

    (2003)
  • N Nagaya et al.

    Oral beraprost sodium improves exercise capacity and ventilatory efficiency in patients with primary or thromboembolic pulmonary hypertension

    Heart

    (2002)
  • O Sitbon et al.

    Inhaled nitric oxide as a screening vasodilator agent in primary pulmonary hypertension: a dose-response study and comparison with prostacyclin

    Am J Respir Crit Care Med

    (1995)
  • O Raffy et al.

    Clinical significance of the pulmonary vasodilator response during short-term infusion of prostacyclin in primary pulmonary hypertension

    Circulation

    (1996)
  • RJ Barst et al.

    Diagnosis and differential assessment of pulmonary arterial hypertension

    J Am Coll Cardiol

    (2004)
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    Drs. Ulrich, Fischler, Speich, Popov, and Maggiorini have been supported in attending research meetings by Actelion/Switzerland and Schering/Switzerland. Dr. Popov worked for 6 months (2002) at Actelion/Switzerland. Dr. Speich has received educational grants from Roche/Switzerland, Actelion/Switzerland, and Schering/Switzerland, and receives financial support for a study nurse from Actelion/Switzerland and Schering/Switzerland.

    Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).

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