Functional Characterization of Patients with Chronic Thromboembolic Disease

• Published in: Respiration Vol. 91; no. 6; pp. 503 - 509
• Main Authors: Held, Matthias, Kolb, Philipp, Grün, Maria, Jany, Berthold, Hübner, Gudrun, Grgic, Aleksandar, Holl, Regina, Schaefers, Hans-Joachim, Wilkens, Heinrike
• Format: Journal Article
• Language: English
• Published: Basel, Switzerland S. Karger AG 01.01.2016
• Subjects: Aged; Aged, 80 and over; Blood clots; Care and treatment; Chronic Disease; Clinical Investigations; Development and progression; Dyspnea - physiopathology; Exercise; Exercise Test; Exercise Tolerance; Female; Health aspects; Humans; Lung diseases; Male; Middle Aged; Physiological aspects; Pulmonary hypertension; Quality of life; Respiration; Retrospective Studies; Thromboembolism; Thromboembolism - physiopathology; Canada; Chronic thromboembolic pulmonary hypertension; Chronic thromboembolic pulmonary disease; Mean pulmonary artery pressure
• ISSN: 0025-7931; 1423-0356; 1423-0356
• DOI: 10.1159/000447247

Background: Patients with chronic thromboembolic pulmonary disease (CTED) have persistent pulmonary vascular obstruction and exercise intolerance without pulmonary hypertension at rest and may benefit from pulmonary endarterectomy. However, up to now, CTED has been poorly characterized. Objectives: This study aimed to analyze the exercise capacity and limiting factors in CTED. Methods: We compared right heart catheterization and cardiopulmonary exercise test results of patients with CTED [mean pulmonary artery pressure (mPAP) at rest <25 mm Hg, n = 10], chronic thromboembolic pulmonary hypertension (CTEPH, n = 31) and a control group (n = 41) presenting with dyspnea but normal pulmonary vascular imaging and excluded pulmonary hypertension. Results: Subjects with CTED show a reduced oxygen uptake [median 76/interquartile range (IQR) 22% pred.] and work rate (median 76/IQR 21 W). The work rate was significantly lower compared to control subjects (p = 0.04) but not significantly different from CTEPH patients (p = 0.66). Oxygen pulse and breathing reserve were normal. CTED subjects showed decreased end-tidal CO 2 at anaerobic threshold (28.4/4.3 mm Hg), an elevated V E /V CO 2 slope (42.5/23.5), breathing equivalents (EQ O 2 32.0/8.7, EQ CO 2 39.5/8.8), alveolar-capillary oxygen gradient (34.7/15.5 mm Hg) and capillary end-tidal carbon dioxide gradient (8.8/5.7 mm Hg) compared to control subjects (p < 0.001). The degree of limitation was similar to that in CTEPH. Conclusions: Despite an mPAP of <25 mm Hg, subjects with CTED show objective functional impairment and similar limitations to patients with CTEPH. Functional limitation is characterized by gas exchange disturbance and ineffective ventilation.