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J Heart Lung Transplant. 2017 Nov;36(11):1234-1242. doi: 10.1016/j.healun.2017.05.024. Epub 2017 May 22.

Dead-space ventilation is linked to exercise capacity and survival in distal chronic thromboembolic pulmonary hypertension.

Author information

1
Université Paris-Sud, Le Kremlin-Bicêtre, France; AP-HP, Service de Pneumologie, Centre de Référence de l׳Hypertension Pulmonaire Sévère, DHU Thorax Innovation, Hôpital Bicêtre, Le Kremlin-Bicêtre, France; INSERM UMR_S999, LabEx LERMIT, Centre Chirurgical Marie Lannelongue, Le Plessis-Robinson, France; CHU UCL Namur, Université Catholique de Louvain, Département de Pneumologie, Yvoir, Belgium. Electronic address: laurent.godinas@uclouvain.be.
2
Université Paris-Sud, Le Kremlin-Bicêtre, France; AP-HP, Service de Pneumologie, Centre de Référence de l׳Hypertension Pulmonaire Sévère, DHU Thorax Innovation, Hôpital Bicêtre, Le Kremlin-Bicêtre, France; INSERM UMR_S999, LabEx LERMIT, Centre Chirurgical Marie Lannelongue, Le Plessis-Robinson, France.
3
Université Paris-Sud, Le Kremlin-Bicêtre, France; AP-HP, Service de Pneumologie, Centre de Référence de l׳Hypertension Pulmonaire Sévère, DHU Thorax Innovation, Hôpital Bicêtre, Le Kremlin-Bicêtre, France; INSERM UMR_S999, LabEx LERMIT, Centre Chirurgical Marie Lannelongue, Le Plessis-Robinson, France; Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Camperdown, New South Wales, Australia.
4
Université Paris-Sud, Le Kremlin-Bicêtre, France; AP-HP, Service de Pneumologie, Centre de Référence de l׳Hypertension Pulmonaire Sévère, DHU Thorax Innovation, Hôpital Bicêtre, Le Kremlin-Bicêtre, France; INSERM UMR_S999, LabEx LERMIT, Centre Chirurgical Marie Lannelongue, Le Plessis-Robinson, France; Department of Medicine, Division of Respirology University of Calgary, Calgary, Alberta, Canada.
5
AP-HP, Groupe Hospitalier Pitié-Salpêtrière Charles Foix, Service des Explorations Fonctionnelles de la Respiration, de l׳Exercice et de la Dyspnée, Paris, France; Sorbonne Universités, UPMC Université Paris 06, UMR_S 1158, Neurophysiologie Respiratoire Expérimentale et Clinique, Paris, France.

Abstract

BACKGROUND:

Cardiopulmonary exercise testing (CPET) is frequently used for the evaluation of patients with pulmonary hypertension (PH). Non-operable distal chronic thromboembolic pulmonary hypertension (CTEPH) represents a unique subgroup of PH where microvascular disease resembling pulmonary arterial hypertension (PAH) may predominate and efficacious medical therapy is now available. However, little is known regarding the detailed CPET profile of patients with distal CTEPH, and whether ventilation and gas exchange responses are different from PAH.

METHODS:

Forty-nine consecutive patients with non-operable distal CTEPH according to multidisciplinary team assessment and 45 PAH patients underwent CPET and right heart catheterization. Patients were followed up for a median of 3.2 years (interquartile range: 1.8 to 4.4).

RESULTS:

Pulmonary hemodynamics were similar in distal CTEPH and PAH groups, but patients with distal CTEPH achieved a lower percent predicted peak oxygen consumption (59 ± 13% vs 66 ± 14%, p < 0.05). At peak exercise, higher physiologic dead-space fraction (VD/VT) (0.45 ± 0.07 vs 0.35 ± 0.07, p < 0.0001) and higher arterial-to-end-tidal carbon dioxide gradient (9 ± 3 vs 5 ± 3 mm Hg, p < 0.0001) were observed in distal CTEPH compared with PAH. Ventilatory efficiency, expressed as VE/VCO2 slope, was also more impaired in distal CTEPH (52.2 ± 10.1 vs 43.8 ± 8.4 liters/min, p < 0.0001). In the distal CTEPH group only, higher VD/VT was associated with lower peak oxygen consumption (r = -0.46, p = 0.003) and worse survival.

CONCLUSIONS:

Compared with PAH, a distinct pattern of response to exercise was observed in distal CTEPH, characterized by increased dead-space ventilation that resulted in worse ventilatory efficiency and greater impairment of exercise capacity. In distal CTEPH, dead-space ventilation correlated with exercise capacity and was associated with survival.

KEYWORDS:

cardiopulmonary exercise test; chronic thromboembolic disease; gas exchange; physiologic dead space; pulmonary artery hypertension; ventilatory efficiency

PMID:
28666570
DOI:
10.1016/j.healun.2017.05.024
[Indexed for MEDLINE]

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