Long-term survival after a pharmacoinvasive strategy in patients with ST-elevation myocardial infarction and long distances to primary percutaneous coronary intervention – a prospective cohort study
Authors: Kvakkestad K M , Gran J M , Halvorsen S 
Published: October 2021

Abstract

Background
In patients with ST-elevation myocardial infarction (STEMI), a pharmacoinvasive (PI) strategy is the recommended reperfusion method if primary percutaneous coronary intervention (pPCI) cannot be performed within 120 minutes from diagnosis. Long-term prognosis for STEMI patients with long transfer distances to pPCI is sparsely documented.

Purpose
To compare short- and long-term survival, and cardiovascular (CV) death in STEMI patients treated with PI or pPCI strategy.

Methods
Consecutive STEMI patients admitted to our cardiac invasive centre were registered prospectively during 2005–2011 in a local quality registry. Follow-up data throughout 2013 were provided by the Norwegian Cause of death registry. Effects of treatment strategy were determined using a propensity score weighted analysis, adjusting for treatment-outcome confounding. Outcomes were 30-day mortality, overall survival and CV death during follow-up.

Results
Of 4762 STEMI patients, 543 (11.4%) were treated with thrombolysis before admission for rescue- or early coronary angiography (PI strategy), and 4044 (84.9%) were admitted for a pPCI strategy (3,7% excluded due to unspecified treatment strategy). Median age was 60 and 63 years in the PI and pPCI groups (19.5% and 24.1% women, respectively). Median time to reperfusion was 110 minutes (25–75th percentile: 75–163; symptom-to-thrombolysis) versus 230 minutes (149–435; symptom-to-balloon). Crude 30-day mortality was 3.9% and 6.6% in the PI- and pPCI groups. Median follow-up was 4.5 years (max 8.3 years). The overall 8-year survival was 84.6% (95% CI 79.4–88.4) in the PI group and 72.6% (95% CI 70.1–74.9) in the pPCI group (crude hazard ratio [HR] 0.56 (95% CI 0.43–0.72, p&lt;0.0001). After propensity score weighting (based on age, gender, smoking, previous hypertension, stroke, diabetes, myocardial infarction, angina pectoris and peripheral artery disease, kidney function and pre-hospital resuscitation), patients had estimated 25% lower risk of long-term mortality with a PI strategy (weighted HR 0.75; 95% CI 0.53–1.07, p=0.113, Figure 1A). Cumulative incidence rate of CV death was 12.8 (PI strategy) and 27.8 (pPCI strategy) pr 1000 person-years (crude incidence rate ratio 0.46; 95% CI 0.32–0.68, p&lt;0.0001), and was significantly lower in the PI group after weighting on the propensity score (p=0.048, Figure 1B).

Conclusions
There was a non-significant 25% lower risk of mortality up to 8 years with a PI versus pPCI strategy in STEMI patients with long transfer distances to PCI, after adjustment for treatment-outcome confounding. Importantly, long-term incidence of CV death was significantly lower in the PI group. These findings from real life practice support the use of a PI strategy in STEMI patients without contraindications to thrombolysis, when pPCI within 120 minutes from diagnosis is not possible.

Funding Acknowledgement
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Funded by grant form the Scientific Board of the Southeastern Norway Regional Health Authority, Hamar, Norway.