Failed Thrombus Aspiration and Decreased Myocardial Perfusion in Patients with STEMI and High Thrombus Load

Half of the patients undergoing percutaneous transluminal coronary angioplasty (PTCA) in a setting of ST-segment elevation acute myocardial infarction (STEMI) experience inadequate myocardial perfusion, known as the no-reflow phenomenon, which contributes to cardiac remodeling and increases mortality. For this reason, effective thrombus removal could reduce the incidence of no-reflow and improve clinical outcomes.

However, studies such as TASTE (Thrombus Aspiration in ST-Elevation Myocardial Infarction in Scandinavia) and TOTAL (Trial of Routine Aspiration Thrombectomy with PCI versus PCI Alone in Patients with STEMI) showed no significant clinical benefits derived from the use of thrombus aspiration (TA). Consequently, its routine application is not recommended. Despite this, many operators continue to perform TA in STEMI patients with a high thrombus load.

The objective of this subanalysis of the Gangwon PCI Registry, a prospective, multicenter, observational registry, was to investigate the effect of failed TA on myocardial perfusion and clinical outcomes in STEMI patients with a high thrombus load who underwent PTCA. Additionally, researchers assessed clinical and angiographic predictors associated with TA failure.

The primary endpoint (PE) was the final TIMI angiographic flow after PTCA. The secondary endpoint (SE) included the final myocardial blush grade, electrocardiographic ST-segment resolution, microvascular obstruction, infarct size (measured by cardiac magnetic resonance imaging), all-cause mortality, cardiovascular mortality, stent thrombosis, and treated-vessel revascularization at one month.

The study included a total of 812 STEMI patients with a high thrombus load who underwent PTCA. Of these, 279 had failed TA and 533 had successful TA. Patients with failed TA were older, but there were no significant differences between the groups in terms of gender, risk factors, or time since the onset of infarction.

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The proportion of final TIMI flow grade 3 was lower in the failed TA group compared to the successful TA group (74.6% vs. 82.2%; P = 0.011). Similarly, the failed TA group showed lower myocardial perfusion (reduced blush grade), less electrocardiographic ST-segment resolution, and a higher incidence of microvascular obstruction. TA failure was independently associated with lower final TIMI flow (hazard ratio: 1.525; 95% confidence interval [CI]: 1.048-2.218; P = 0.027).

Factors associated with TA failure included older age, Killip class ≥III, vessel tortuosity, calcification, and a culprit vessel other than the left anterior descending artery.

Conclusion

Failed TA was associated with reduced myocardial perfusion in STEMI patients with a high thrombus load who underwent primary PTCA. Older age, hemodynamic instability, tortuosity and calcification of the infarct-related artery, and involvement of arteries other than the left anterior descending artery reduce the effectiveness of thrombus aspiration in a setting of STEMI.

Original Title: Failed Thrombus Aspiration and Reduced Myocardial Perfusion in Patients With STEMI and Large Thrombus Burden.

Reference: Ho Sung Jeon, MD et al JACC Cardiovasc Interv. 2024.