AimsSpontaneous coronary artery dissection (SCAD) was underdiagnosed and poorly understood for decades. It is increasingly recognized as an important cause of myocardial infarction (MI) in women. We aimed to assess the natural history of SCAD, which has not been adequately explored.
Background:
Recent clinical trial data support a pharmacoinvasive strategy as an alternative to primary percutaneous coronary intervention (pPCI) in ST-segment elevation myocardial infarction. We evaluated whether this is true in a real-world prehospital ST-segment elevation myocardial infarction network using ECG assessment of reperfusion coupled with clinical outcomes within 1 year.
Methods:
Of the 5583 ST-segment elevation myocardial infarction patients in the Alberta Vital Heart Response Program (Cohort 1 [2006–2011]: n=3593; Cohort 2 [2013–2016]: n=1990), we studied 3287 patients who received a pharmacoinvasive strategy with tenecteplase (April 2013: half-dose tenecteplase was employed in prehospital patients ≥75 years) or pPCI. ECGs were analyzed within a core laboratory; sum ST-segment deviation resolution ≥50% was defined as successful reperfusion. The primary composite was all-cause death, congestive heart failure, cardiogenic shock, and recurrent myocardial infarction within 1 year.
Results:
The pharmacoinvasive approach was administered in 1805 patients (54.9%), (493 [27.3%] underwent rescue/urgent percutaneous coronary intervention and 1312 [72.7%] had scheduled angiography); pPCI was performed in 1482 patients (45.1%). There was greater ST-segment resolution post-catheterization/percutaneous coronary intervention with a pharmacoinvasive strategy versus pPCI (75.8% versus 64.3%, IP-weighted odds ratio, 1.59; 95% CI, 1.33–1.90;
P
<0.001). The primary composite was significantly lower with a pharmacoinvasive approach (16.3% versus 23.1%, IP-weighted hazard ratio, 0.84; 95% CI, 0.72–0.99;
P
=0.033). Major bleeding and intracranial hemorrhage were similar between a pharmacoinvasive strategy and pPCI (7.6% versus 7.5%,
P
=0.867; 0.6% versus 0.6%;
P
=0.841, respectively). In the 82 patients ≥75 years with a prehospital pharmacoinvasive strategy, similar ST-segment resolution and rescue rates were observed with full-dose versus half-dose tenecteplase (75.8% versus 88.9%,
P
=0.259; 31.0% versus 29.2%,
P
=0.867) with no difference in the primary composite (31.0% versus 25.0%,
P
=0.585).
Conclusions:
In this large Canadian ST-segment elevation myocardial infarction registry, a pharmacoinvasive strategy was associated with improved ST-segment resolution and enhanced outcomes within 1 year compared with pPCI. Our findings support the application of a selective pharmacoinvasive reperfusion strategy when delay to pPCI exists.
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