Prevalence and outcomes of patients with SMuRF-less acute coronary syndrome undergoing percutaneous coronary intervention.

backgroundThere is increasing awareness that patients without standard modifiable risk factors (SMuRFs; diabetes, hypercholesterolaemia, hypertension and smoking) may represent a unique subset of patients with acute coronary syndrome (ACS). We aimed to investigate the prevalence and outcomes of patients with SMuRF-less ACS undergoing percutaneous coronary intervention (PCI) compared with those with SMuRFs.

methodsWe analysed data from the Melbourne Interventional Group PCI Registry. Patients with coronary artery disease were excluded. The primary outcome was 30-day mortality. Secondary outcomes included in-hospital and 30-day events. Long-term mortality was investigated using Cox-proportional hazards regression.

resultsFrom 1 January 2005 to 31 December 2020, 2727/18 988 (14.4%) patients were SMuRF less, with the proportion increasing over time. Mean age was similar for patients with and without SMuRFs (63 years), and fewer females were SMuRF-less (19.8% vs 25.4%, p<0.001). SMuRF-less patients were more likely to present with cardiac arrest (6.6% vs 3.9%, p<0.001) and ST-elevation myocardial infarction (59.1% vs 50.8%, p<0.001) and were more likely to experience postprocedural cardiogenic shock (4.5% vs 3.6%, p=0.019) and arrhythmia (11.2% vs 9.9%, p=0.029). At 30 days, mortality, myocardial infarction, revascularisation and major adverse cardiac and cerebrovascular events did not differ between the groups. During median follow-up of 7 years, SMuRF-less patients had an adjusted 13% decreased rate of mortality (HR 0.87 (95% CI 0.78 to 0.97)).

conclusionsThe proportion of SMuRF-less patients increased over time. Presentation was more often a devastating cardiac event compared with those with SMuRFs. No difference in 30-day outcomes was observed and SMuRF-less patients had lower hazard for long-term mortality.