Effects of Exercise and Vasodilators on Cerebral Tissue Oxygenation in Pulmonary Hypertension

• Published in: Lung Vol. 193; no. 1; pp. 113 - 120
• Main Authors: Müller-Mottet, Séverine, Hildenbrand, Florian F., Keusch, Stephan, Hasler, Elisabeth, Maggiorini, Marco, Speich, Rudolf, Bloch, Konrad E., Ulrich, Silvia
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01-02-2015; Springer; Springer Nature B.V
• Subjects: Administration, Inhalation; Aged; Antihypertensive Agents - administration & dosage; Brain - blood supply; Brain - drug effects; Brain - metabolism; Cardiac Catheterization; Care and treatment; Cerebrovascular Circulation - drug effects; Complications and side effects; Exercise; Exercise Test; Exercise Tolerance - drug effects; Female; Humans; Hypertension; Hypertension, Pulmonary - diagnosis; Hypertension, Pulmonary - physiopathology; Hypertension, Pulmonary - therapy; Male; Medicine; Medicine & Public Health; Middle Aged; Multivariate Analysis; Nitric Oxide - administration & dosage; Oxygen - blood; Oxygen Consumption - drug effects; Oxygen Inhalation Therapy; Oxygen therapy; Physiological aspects; Pneumology/Respiratory System; Predictive Value of Tests; Pulmonary hypertension; Spectroscopy, Near-Infrared; Switzerland; Temperature effects; Time Factors; Tissues; Treatment Outcome; Vasodilator Agents - administration & dosage; Switzerland; Cerebral tissue oxygenation; Pulmonary hypertension; Exercise
• ISSN: 0341-2040; 1432-1750
• DOI: 10.1007/s00408-014-9667-5

Background
Arterial and thromboembolic pulmonary hypertension (PH) lead to arterial hypoxaemia.
Objective
To investigate whether cerebral tissue oxygenation (CTO) in patients with PH is reduced and whether this is associated with reduced exercise tolerance.
Methods
16 patients with PH (mean pulmonary arterial pressure ≥25 mmHg, 14 arterial, 2 chronic thromboembolic) and 15 controls underwent right heart catheterisation with monitoring of CTO at rest, during maximal bicycle exercise and during inhalation of oxygen and NO. The 6 min walk distance (6MWD) was measured.
Results
Median CTO in PH-patients at rest was 62 % (quartiles 53; 71), during exercise 60 % (53; 65); corresponding values in controls were 65 % (73; 73) (P = NS) and 68 % (66; 70) (
p
 = .013 vs. PH). Inhalation of NO and oxygen improved CTO in PH. In multivariate regression analysis CTO at maximal exercise predicted the work load achieved when controlled for age, pulmonary vascular resistance and mixed venous oxygen saturation (
R
2
 = .419,
p
 < .000); in addition, the 6MWD was predicted by CTO (adjusted
R
2
 = .511,
p
 < .000).
Conclusion
In PH-patients but not in controls CTO decreased during exercise. Since CTO was an independent predictor of the work load achieved and the 6MWD cerebral hypoxia may contribute to exercise limitation in PH. Clinicaltrials.gov: NCT01463514.