Effects of a rehabilitation program on skeletal muscle function in idiopathic pulmonary arterial hypertension

J Cardiopulm Rehabil Prev. Sep-Oct 2010;30(5):319-23. doi: 10.1097/HCR.0b013e3181d6f962.

Abstract

Introduction: 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.

Discussion: Peripheral muscle characteristic improvements may contribute to the clinical benefit observed following a rehabilitation program in IPAH.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Antihypertensive Agents / therapeutic use
  • Bicycling / physiology*
  • Bosentan
  • Exercise Test
  • Exercise Tolerance / physiology*
  • Familial Primary Pulmonary Hypertension
  • Female
  • Health Status Indicators
  • Humans
  • Hypertension, Pulmonary / rehabilitation
  • Male
  • Middle Aged
  • Muscle Contraction / physiology
  • Muscle, Skeletal / physiology*
  • Oxygen Consumption
  • Phosphodiesterase 5 Inhibitors / therapeutic use
  • Pilot Projects
  • Piperazines / therapeutic use
  • Program Evaluation
  • Purines / therapeutic use
  • Quadriceps Muscle / physiology
  • Sildenafil Citrate
  • Sulfonamides / therapeutic use
  • Sulfones / therapeutic use
  • Treatment Outcome

Substances

  • Antihypertensive Agents
  • Phosphodiesterase 5 Inhibitors
  • Piperazines
  • Purines
  • Sulfonamides
  • Sulfones
  • Sildenafil Citrate
  • Bosentan