Time to Medical Management in Patients Presenting with Non-ST Elevation Myocardial Infarction: A Retrospective Analysis of Two Teaching Hospitals

Background: It is clear that early administration of antiplatelet and antithrombotic therapy in patients presenting with Non-ST elevation MI (NSTEMI) is associated with improved outcomes. There are existing guidelines regarding early treatment in this patient population. We investigated how effectively patients are being managed for NSTEMI with respect to time to administration of indicated medical therapies in two teaching institutions.Methods: A retrospective analysis was performed on 100 consecutive patients with no prior history of coronary artery disease who presented to the Emergency Departments of two teaching hospitals affiliated with McMaster University with the diagnosis of NSTEMI (defined as ischemic symptoms in presence of elevated cardiac biomarkers with or without electrocardiographic changes). Times of medication administration were obtained from the nursing notes.Results: The mean age was 63.9 ± 14.1 years. The average time to administration of aspirin was 2.7 ± 4.3 hours, Unfractionated or Low Molecular Weight Heparin 5.4 ± 5.0 hours, and Clopidagrel 10.8 ± 16.5 hours from time of triage. Duration of symptoms prior to presentation were longer in patients with left ventricular (LV) dysfunction (on echocardiography assessed in 73 patients) compared to patients with normal LV, (7.5 h ± 8.3 vs. 3.3 h ± 3.4 p = 0.006). The average age of patients who had ASA, Heparin, and Clopidagrel initiated within 3 hours was lower than those after 6 hours (60.1 ± 12.7 years vs 68.1 ± 14.4 years, p = 0.01). The average age for those who underwent angiography ± percutaneous coronary intervention (PCI) was also lower at 60.2 ± 11.8 versus 76.1 ± 14.4 years (p = 0.0001).Conclusions: There was a lag time in the administration of established medical therapies in patients presenting with first time NSTEMI. An age bias towards time to treat and selection for PCI may have also existed. The fact that increased duration of symptoms was associated with worse LV function may provide impetus for early recognition and management of patients with NSTEMI.