Research Assistant New Brunswick Heart Centre Saint John, New Brunswick, Canada
Background: Primary percutaneous coronary intervention (PPCI) is the preferred treatment for ST-Segment Elevation Myocardial Infarction (STEMI) but is generally limited to patients for whom intervention can be performed within 90 minutes of diagnosis. In New Brunswick (NB) and Prince Edward Island (PEI), many patients present to non-PCI capable centres first and receive thrombolysis. They are then immediately transferred to the New Brunswick Heart Centre (NBHC) for subsequent management, including rescue PCI (RPCI) in the event of failed reperfusion. Wide variation in transfer distances to the NBHC raise concerns of prolonged ischemic times for select RPCI patients. Therefore, we sought to assess the efficacy of the RPCI program at the NBHC.
METHODS AND RESULTS: A total of 1439 consecutive STEMI patients referred to the NBHC between January 2019 and August 2021 were included in this analysis. In this group, 939 patients (65.2%) received thrombolytic therapy, of whom 429 patients (29.8%) failed to reperfuse and subsequently required RPCI. Rescue PCI patients were stratified based on distance from the referring centre to the NBHC (0 – 150km, n = 161; 151 – 300km, n = 162; 301 – 450km, n = 106). Patient characteristics were similar at baseline, including age, sex distribution, and prevalence of key STEMI comorbidities including hypertension and diabetes. Median transfer-associated time increased significantly with distance [0-150km, 129mins (109-150); 151-300km, 209mins (169-265); 301-450km, 273mins (240-311), p < 0.0001]. The proportion of those arriving with signs of cardiogenic shock (0 – 150km, 8.7%; 151 – 300km, 6.8%; 301 – 450km, 10.1%, p = 0.56) or having suffered a cardiac arrest (0 – 150km, 8.7%; 151 – 300km, 10.5%; 301 – 450km, 10.5%, p = 0.83) did not significantly increase with distance. Similarly, the rate of those requiring vasoactive support after RPCI (0-150km, 16.6%; 151-300km, 14.1%; 301-450km, 15.9%, p = 0.91), or cardiac surgery (0-150km, 8.1%; 151-300km, 5.0%; 301-450km, 12.2%, p = 0.11) did not significantly differ. The in-hospital mortality was also comparable between groups (0-150km, 4.4%; 151-300km, 1.9%; 301-450km, 1.9%, p = 0.35).
Conclusion: We report data from a large cohort of STEMI patients served by a single tertiary cardiac centre in which the majority receive primary thrombolytic strategy due largely to geographic limitations. Our unique experience suggests that despite thrombolytics, nearly half of this patient population required RPCI. Having said that, patients being transferred from up to 450 km away achieved acceptable outcomes despite the inherent geographical disadvantage.
