Remote Ischemic Conditioning (RIC)

RIC is the repeated inflation (usually 5 minutes) and deflation of a blood pressure cuff for a number of cycles (usually 4 or 5) on an extremity to protect a distant organ such as the brain from ischemia. RIC can be administered before an ischemic event (remote ischemic preconditioning), during an ischemic event (remote ischemic perconditioning) or after an ischemic event, during reperfusion (remote ischemic postconditoning)  (Hess et al., 2013) RIC is a form of  preconditioning and follows the principle that a small dose of a harmful agent protects against a later lethal dose of that agent. RIC elicits a protective or “ischemia tolerant” phenotype. RIC has multiple mechanisms of action including improving collateral flow (likely by increasing NOS3) and providing tissue protection by effects on the mitochondria. (Hess et al., 2015)

Fig. RIC applied bilaterally on the lower extremities in mice

Our laboratory showed that RIC was effective in an autologous thromboembolic model in young male mice, in ovariectomized females, and in combination with ”late “tissue plasminogen activator (tPA). (Hoda et al., 2012)(Hoda, Bhatia, et al., 2014)(Hoda, Fagan, et al., 2014). We also showed that RIC acutely increases CBF in the ischemic hemisphere in acute ischemic stroke and increases CBF long term in a chronic ischemia model, the bilateral carotid artery stenosis model in mice.(Khan et al., 2014, 2018)

Moreover, our group showed that RIC is effective in both the collagenase and autologous blood injection models of intracerebral hemorrhage ( ICH ) in improving outcome and hastening clot resolution when administered for 5 days. (Vaibhav et al., 2018)

The safety and efficacy of RIC in preclinical   acute stroke and ICH models suggests RIC may be an ideal intervention to use in the prehospital setting. RIC is simple, safe, and inexpensive and be applied in the ambulance, helicopter, Emergency Department, hospital, and home.