Patients who have a heart attack followed by return of spontaneous circulation (ROSC), but not consciousness, have a poor prognosis. The neurological outcomes for these so-called ROSC patients can be aided by rapid cooling of the body (therapeutic hypothermia) in the cardiac catheterization lab, but many questions remain about implementing this treatment.
Resident Ifrah Abdirahman presented a comparison of outcomes between ROSC patients with and without an ST-elevation myocardial infarction (STEMI) who underwent cooling after their arrival at the hospital. The expectation was that patients with STEMI, the most dangerous type of heart attack, would have worse neurological outcomes, but found this was not the case.
The two groups spent similar lengths of time in the hospital, and similar numbers of patients in both groups were discharged home, a marker of favourable neurological outcome. These results indicate that cooling in conjunction with immediate percutaneous coronary intervention (PCI: angioplasty and stenting) is feasible in comatose STEMI patients.
Dr. Rohit Moudgil, a fifth-year resident, discussed a worrisome finding for patients undergoing simultaneous cooling and PCI: that the drug clopidogrel, given to prevent dangerous blood clots after stenting, does not appear to work well at colder body temperatures. He and his colleagues tested blood from ROSC patients after 24 hours of cooling and found that almost none showed any platelet inhibition after clopidogrel administration. Interestingly, ROSC patients at normal body temperature also showed minimal platelet inhibition with clopidogrel. Other platelet inhibitors should be evaluated in these patients, he concluded.