title: Ischemic preconditioning of the lower extremity attenuates the normal hypoxic increase in pulmonary artery systolic pressure.
abstract: Ischemic pre-condition of an extremity (IPC) induces effects on local and remote tissues that are protective against ischemic injury. To test the effects of IPC on the normal hypoxic increase in pulmonary pressures and exercise performance, 8 amateur cyclists were evaluated under normoxia and hypoxia (13% F(I)O(2)) in a randomized cross-over trial. IPC was induced using an arterial occlusive cuff to one thigh for 5 min followed by deflation for 5 min for 4 cycles. In the control condition, the resting pulmonary artery systolic pressure (PASP) increased from a normoxic value of 25.6±2.3 mmHg to 41.8±7.2 mmHg following 90 min of hypoxia. In the IPC condition, the PASP increased to only 32.4±3.1 mmHg following hypoxia, representing a 72.8% attenuation (p=0.003). No significant difference was detected in cycle ergometer time trial duration between control and IPC conditions with either normoxia or hypoxia. IPC administered prior to hypoxic exposure was associated with profound attenuation of the normal hypoxic increase of pulmonary artery systolic pressure.
authors.affiliation: Cardiology Section, Medical Service, VA Loma Linda HealthCare System, Loma Linda, CA 92357, United States. gary.foster2@va.gov
authors.forename: Gary P
authors.initials: GP
authors.lastname: Foster
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Westerdahl
authors.forename: Laura A
authors.initials: LA
authors.lastname: Foster
authors.forename: Jeffrey V
authors.initials: JV
authors.lastname: Hsu
authors.forename: James D
authors.initials: JD
authors.lastname: Anholm
mesh_terms: D000328:Adult; D001794:Blood Pressure / Q000502:physiology*; D018592:Cross-Over Studies; D018618:Echocardiography, Doppler, Color; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D019194:Ischemic Preconditioning; D007866:Leg / Q000098:blood supply; D008297:Male; D008875:Middle Aged; D011651:Pulmonary Artery / Q000502:physiology