Feasibility of Remote Ischemic Peri-conditioning during Air Medical Transport of STEMI Patients

Abstract

Remote ischemic peri-conditioning (RIPC) has gained interest as a means of reducing ischemic injury in patients with acute ST-elevation myocardial infarction (STEMI) who are undergoing emergent primary percutaneous coronary intervention (pPCI). We aimed to evaluate the feasibility, process, and patient-related factors related to the delivery of RIPC during air medical transport of STEMI patients to tertiary pPCI centers. We performed a retrospective review of procedural outcomes of a cohort of STEMI patients who received RIPC as part of a clinical protocol in a multi-state air medical service over 16 months (March 2013 to June 2014). Eligible patients were transported to two tertiary PCI centers and received up to four cycles of RIPC by inflating a blood pressure cuff on an upper arm to 200 mmHg for 5 minutes and subsequently deflating the cuff for 5 minutes. Data regarding feasibility, process variables, patient comfort, and occurrence of hypotension were obtained from prehospital records and prospectively completed quality improvement surveys. The primary outcome was whether at least 3 cycles of RIPC were completed by air medical transport crews prior to pPCI. Secondary outcomes included the number of cycles completed prior to pPCI, time spent with the patient prior to transport (bedside time), patient discomfort level, and incidence of hypotension (systolic blood pressure <90 mmHg) during the procedure. RIPC was initiated in 99 patients (91 interfacility, 8 scene transports) and 83 (83.3%) received 3 or 4 cycles of RIPC, delivered over 25–35 minutes. Median bedside time for interfacility transfers was 8 minutes (IQR 7, 10). More than half of patients reported no pain related to the procedure (N = 53, 53.3%), whereas 5 (5.1%) patients reported discomfort greater than 5 out of 10. Two patients developed hypotension while receiving RIPC and both had experienced hypotension prior to initiation of RIPC. RIPC is feasible and safe to implement for STEMI patients undergoing air medical transport for pPCI, without occurrence of prolonged bedside times. The incidence of excessive RIPC-related discomfort or hemodynamic instability is rare. STEMI patients requiring on average >30 minutes transport for pPCI may be the ideal group for RIPC utilization.

Key words::

• remote ischemic conditioning
• emergency medical services
• ST-elevation myocardial infarction