Selective Use of Thromboaspiration in STEMI: CMR Evidence Against Routine Practice

Thromboaspiration (TA) has been proposed as an adjunct to primary percutaneous coronary intervention (PCI) in ST-elevation myocardial infarction (STEMI) to reduce thrombus burden. However, its effect on microvascular perfusion remains uncertain, and concerns have been raised about its potential to aggravate microvascular injury. This study aimed to evaluate the impact of TA on microvascular obstruction (MVO) using cardiac magnetic resonance imaging in a large cohort of STEMI patients. We prospectively enrolled 460 STEMI patients treated with primary PCI within 12 hours of symptom onset. TA was performed in 193 patients (42%). Cardiac magnetic resonance was performed at day 6 and 3 months to assess infarct size and MVO. A propensity score-based average treatment effect analysis was used to adjust for baseline differences. Subgroup analyses were conducted according to symptom-to-treatment time, thrombus burden (thrombolysis in myocardial infarction thrombus score), and sex. TA was independently associated with higher MVO incidence (odds ratios [OR] 1.52; 95% confidence intervals [CI]: 1.16 to 1.98; p = 0.0024) and greater MVO extent (standardized mean differences 0.42; 95% CI: 0.02 to 0.72; p = 0.041). The association was particularly significant in patients reperfused beyond 6 hours (OR 3.46; 95% CI: 1.92 to 6.23; p < 0.0001) and those with nonocclusive thrombus (thrombolysis in myocardial infarction thrombus score "1 to 4") (OR 2.23; 95% CI: 1.29 to 3.85; p = 0.004). Sex-stratified analysis showed increased MVO risk in men (OR 1.52; 95% CI: 1.14 to 2.05; p = 0.005) but not in women. TA during primary PCI was associated with increased occurrence and extent of MVO, particularly in patients with delayed reperfusion or nonocclusive thrombus. These findings reinforce current ESC guidelines against routine TA use and suggest that its application should be restricted to carefully selected patients.