Effects of a rehabilitation program on skeletal muscle function in idiopathic pulmonary arterial hypertension.
BACKGROUND
A majority of patients with idiopathic pulmonary arterial hypertension (IPAH) display persistent exercise intolerance despite current therapies. Whether a rehabilitation program elicits favorable changes in muscle function which would partly explain improvements in exercise tolerance of IPAH patients remains unknown. We performed this study to assess the effect of a 12-week rehabilitation program on skeletal muscle characteristics and exercise tolerance in patients with IPAH.


METHODS
Exercise capacity measured by the 6-minute walk test and by the cycle endurance test (CET), limb muscle cross-sectional area, quadriceps function by maximal voluntary contraction and magnetic stimulation (potentiated twitches), and molecular muscle characteristics by quadriceps biopsy of 5 IPAH patients were assessed before and after a 12-week rehabilitation program.


RESULTS
Following training, improvements in all patients were observed for the 6-minute walk test distance, from 441 (75) to 499 (85) m, P = .01, and the CET time, from 429 (239) to 633 (380) seconds, P = .16. Minute ventilation assessed at isotime during CET decreased by 15(11)%, P = .05. This was related to both decreased carbon dioxide output and (Equation is included in full-text article.)E/(Equation is included in full-text article.)co2. These improvements were associated with decreased type IIx fiber proportion, 31(8)% to 23(10)%, P = .05.


CONCLUSIONS
Peripheral muscle characteristic improvements may contribute to the clinical benefit observed following a rehabilitation program in IPAH.
Mainguy
Vincent
V
Centre de recherche de l'Institut universitaire de cardiologie et de pneumologie de Québec, chemin Sainte-Foy, Canada.
Maltais
François
F
Saey
Didier
D
Gagnon
Philippe
P
Martel
Simon
S
Simon
Mathieu
M
Provencher
Steeve
S
D000328:Adult; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001642:Bicycling / Q000502:physiology*; D000077300:Bosentan; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D065627:Familial Primary Pulmonary Hypertension; D005260:Female; D006305:Health Status Indicators; D006801:Humans; D006976:Hypertension, Pulmonary / Q000534:rehabilitation; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000502:physiology*; D010101:Oxygen Consumption; D058986:Phosphodiesterase 5 Inhibitors / Q000627:therapeutic use; D010865:Pilot Projects; D010879:Piperazines / Q000627:therapeutic use; D015397:Program Evaluation; D011687:Purines / Q000627:therapeutic use; D052097:Quadriceps Muscle / Q000502:physiology; D000068677:Sildenafil Citrate; D013449:Sulfonamides / Q000627:therapeutic use; D013450:Sulfones / Q000627:therapeutic use; D016896:Treatment Outcome
D000959:Antihypertensive Agents; D058986:Phosphodiesterase 5 Inhibitors; D010879:Piperazines; D011687:Purines; D013449:Sulfonamides; D013450:Sulfones; D000068677:Sildenafil Citrate; D000077300:Bosentan