The substantial and growing proportion of patients who develop STEMI in the absence of standard modifiable cardiovascular risk factors (SMuRFs) is proving a challenge for the cardiac community.
As previously reported in the limbic, patients with STEMI in the absence of SMuRFs have poorer outcomes – increased in-hospital and 30-day all-cause and cardiovascular mortality – which warrants a concerted effort at identifying the underlying pathophysiologic mechanisms at play.
In a new study led by Professor Gemma Figtree, individual patient-level data from 10 randomised STEMI with confirmed CAD trials was interrogated for new clues.
In the cohort of 2,862 patients, 18.3% were SMuRF-less and 81.7% had at least one SMuRF of dyslipidaemia, hypertension, diabetes mellitus or smoking.
The study, published in JACC: Cardiovascular Interventions, found SMuRF-less patients had higher rates of TIMI 0/1 flow pre-PCI compared with SMuRF-positive patients (72% vs 64%, P = 0.0007).
“This association between TIMI flow and SMuRF-less status remained significant after adjusting for age, sex, and LAD versus non-LAD as the culprit lesion (P = 0.011).”
Imaging found no significant association between SMuRF-less status and infarct size, MVO, or LVEF assessed at a median of 4 days post-PCI.
Unlike the SWEDEHEART registry study, SMuRF-less patients in the current study had similar 30-day and 1-year rates of mortality, reinfarction, and hospitalisation for heart failure.
“These discrepancies are likely caused by selection bias as well as greater adherence to guideline-recommended therapies, including those for secondary prevention, within randomised trials compared with what occurs in the “real world,” the study authors said.
They added that medications including statins, ACE inhibitors/ARBs and beta blockers were therefore still important in patients without SMuRFs.
“The substantial proportion of patients who develop STEMI despite no previously diagnosed SMuRF warrants further investigation of potential mechanisms to help guide strategies for both primary and secondary prevention in this patient population,” they wrote.
Beyond traditional risk factors
Professor Figtree told the limbic that primary care had done a creditable job preventing heart attacks in people with traditional risk factors.