title: Mild coronary artery stenosis has no impact on cardiac and vascular parameters in miniature swine exposed to positive acceleration stress.
abstract: BACKGROUND
  Exposure of pilots' heart to acceleration-associated stress (+Gz stress) is an adverse effect of high-performance aviation. The occurrence of coronary heart diseases is one of the most frequent medical causes leading to cessation of flying.
  
  
  OBJECTIVE
  To assess the effects of +Gz stress on coronary artery stenosis (CAS) in a minimally invasive miniature swine model with a fast recovery.
  
  
  METHODS
  The proximal left anterior descending branch was ligated in 20 swine using silk suture. CAS degree (mild, moderate, severe) was analyzed by quantitative computerized angiography. Five swine underwent a sham operation. +Gz stress exposure was performed and venous blood was collected before/after exposure. Plasma C-reactive protein (CRP), endothelin (ET)-1, angiotensin (Ang) II and urotensin 2 (U2) levels were measured.
  
  
  RESULTS
  CAS models were successful in 18 animals. Two swine exhibited ventricular fibrillation during the procedure and died. Plasma CRP, ET-1, Ang II and U2 changed significantly after maximal tolerated +Gz stress exposure (all P < 0.05). After maximal tolerated +Gz stress exposure, plasma CRP, ET-1, Ang II and U2 levels increased in the moderate and severe stenosis groups, compared with the sham group (all P < 0.05), but there was no significant difference between the mild stenosis group and the sham group (all P > 0.05).
  
  
  CONCLUSIONS
  The fully endoscopic operation method successfully generated animal models of different degrees of CAS. Plasma CRP, ET-1, Ang II and U2 levels increased after +Gz stress exposure with increasing CAS severity. Animals with mild stenosis showed no ill effect under +Gz stress, suggesting that pilots with mild stenosis might be allowed to continue flying, but it must be confirmed in humans.
authors: aDepartment of Cardiology, Air Force Clinic Institution of Anhui Medical University bDepartment of Cardiology, General Hospital of Air Force, PLA cAnimal Experimental Center of Fuwai Hospital, National Heart Center of China, Beijing, China.
authors: Haitao
authors: H
authors: Zhang
authors: Huilan
authors: H
authors: Luo
authors: Jinjin
authors: J
authors: Sun
authors: Chaozhong
authors: C
authors: Liu
authors: Yi
authors: Y
authors: Tian
authors: Hao
authors: H
authors: Chen
authors: Chao
authors: C
authors: Zhang
mesh_terms: D000054:Acceleration; D000818:Animals; D002097:C-Reactive Protein / Q000032:analysis; D023921:Coronary Stenosis / Q000503:physiopathology*; D004195:Disease Models, Animal; D006112:Gravitation; D006321:Heart / Q000503:physiopathology*; D006339:Heart Rate; D008297:Male; D013552:Swine; D013556:Swine, Miniature; D013906:Thoracoscopy
chemical_list: D002097:C-Reactive Protein