Prevalence and outcomes of acute coronary syndrome patients with and without standard modifiable risk factors undergoing percutaneous coronary intervention

Abstract

Abstract Background Prevention strategies in acute coronary syndrome (ACS) have focused on patients with standard modifiable risk factors (SMuRFs; diabetes, hypercholesterolaemia, hypertension, and current smoking). There is increasing awareness that SMuRF-less patients may represent a unique subset of patients experiencing ACS. Purpose To investigate the prevalence, characteristics, and outcomes of SMuRF-less ACS patients compared to those with SMuRFs undergoing percutaneous coronary intervention (PCI) in a major city in Australia. Methods We analysed data from adult (≥18 years) ACS patients receiving PCI between 2005 and 2020 using a PCI Registry which contains data for all patients undergoing coronary intervention at one of six major hospitals. Patients with a known history of coronary artery disease were excluded. Overall clinical characteristics and outcomes for those with and without SMuRFs were examined. The primary outcome was 30-day all-cause mortality. Secondary outcomes included in-hospital outcomes, myocardial infarction (MI), revascularisation, and major adverse cardiovascular and cerebrovascular (MACCE) events at 30 days. Long-term mortality was investigated using Cox-proportional hazards regression. Results From 1 January 2005 to 31 December 2020, 2,727 (14.4%) of 18,988 patients were SMuRF-less. Mean (± standard deviation [SD]) age was similar between patients with and without SMuRFs (63±13 vs 63±12 years) and there were more females with SMuRFs (25% vs 20%, p<0.001). SMuRF-less patients were less likely to have a history of cerebrovascular disease (1.2% vs 4.2%, p<0.001), peripheral vascular disease (0.6% vs 3.0%, p<0.001), and chronic lung disease (8.6% vs 10.1%, p=0.014). They were more likely to present with out-of-hospital cardiac arrest (6.6% vs 3.9%, p<0.001) and ST-elevation MI (59% vs 51%, p<0.001). The left anterior descending artery was the target lesion in 46% of SMuRF-less patients compared to 39% of those with SMuRFs. During hospital stay, SMuRF-less patients were more likely to experience post-procedural cardiogenic shock (4.5% vs 3.6%, p=0.019) and arrhythmia (11.2% vs 9.9%, p=0.029). At 30 days, all-cause mortality did not differ between those with and without SMuRFs (3.2% vs 3.6%, p=0.290). Similarly, there were no differences in 30-day MI, revascularisation, and MACCE. During mean follow-up of approximately 7 years, being SMuRF-less was associated with a 12% decreased rate of mortality (adjusted Hazard Ratio 0.88 [95% confidence interval 0.78, 0.99], p=0.035). Conclusions Despite differences in characteristics (rates of cardiac arrest and ST-elevation MI), no difference in 30-day outcomes was observed among those with and without SMuRFs. However, SMuRF-less patients had lower hazard for long-term mortality. These findings suggest SMuRF-less patients may have novel risk factors and improved long-term outcome warranting further research.