Physical ischaemia induced by isometric exercise facilitated collateral development in the remote ischaemic myocardium of humans.

The aim of the present study was to investigate the effects of isometric-handgrip-induced PIT (physical ischaemia training) on remote coronary recruitment and growth. A total of 74 CAD (coronary artery disease) patients were randomly assigned to either the IHG (isometric handgrip group) or NEG (non-exercise group). Patients in the IHG performed isometric handgrip exercises during 1 min of coronary balloon occlusion, whereas patients in the NEG remained sedentary. CFI (collateral flow index), HR (heart rate), SBP (systolic blood pressure) and DBP (diastolic blood pressure) were evaluated before and at the end of occlusion. In a second study, 21 CAD patients were randomly divided into the IHT (isometric handgrip training) group or the NTG (non-training group). Patients in the IHT group performed 3 months of IHT, whereas patients in the control group remained sedentary. SPECT (single-photon emission computed tomography) was used to evaluate myocardial perfusion, and VEGF (vascular endothelial growth factor) levels were determined using ELISA. In the IHG, CFI was significantly higher than in the control group (P<0.01). HR, SBP and DBP in the IHG were significantly higher than in the NEG (P<0.01) at the end of occlusion. In the second study, myocardial perfusion (P<0.05) and left ventricular ejection fraction (P<0.01) were significantly improved in the IHT group. VEGF levels in the IHT group were significantly increased (P<0.01). Levels of VEGF were negatively correlated with the summed rest score of SPECT (r=-0.60, P<0.01). In conclusion, isometric handgrip exercise-induced PIT may promote remote collateral recruitment and growth in CAD patients.