Failed Thrombus Aspiration in STEMI, and Impact

Large Clot Burden (LCB) is known to be a predictor of no-reflow. There is a hypothesis which states that effective thrombus aspiration (TA) might reduce the incidence of this complication, while improving ST elevation MI (STEMI) patient prognosis. 

There are three large randomized studies on TA effectiveness. The TAPAS trial (2008), looked into TA during primary PCI, which resulted in improved perfusion parameters and reduced cardiovascular events. However, researchers were not able to reproduce these outcomes in subsequent studies, such as the TASTE (2013) and the TOTAL (2015). This is why the most relevant clinical guidelines will not recommend TA routine procedure for STEMI patients. Nevertheless, recommendations do not exclude specific clinical situations where TA is needed, such as cases of LCB, or thromboembolic driven MI.

The aim of this study presented by Jeon et al. was to look at the impact of failed TA (defined as failed aspiration of thrombus, remnant thrombus ≥G-2, or distal embolization) on myocardial perfusion and clinical events in patients with STEMI and LCB (defined as thrombotic score ≥3).

This was a subanalysis of the Gangwon PCI Registry (South Korea). Operators conducted manual TA for visible thrombi lesions and complete occlusion. After crossing with a 0.14 guidewire, TA was done with a TA 6F catheter, such as the Thrombuster II and the Export.

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Primary end point was post primary PCI final TIMI flow. Secondary end points included myocardial blush, ST resolution at 90 minutes, microvascular obstruction and infarct size determined by cardiac magnetic resonance (CMR) between 3 and 7 days after AMI, as well as all-cause and cardiovascular mortality, stent thrombosis and need for new revascularization at 30 days. 

Of total 1804 STEMI patients undergoing primary PCI, 812 were eligible because of LCB. Mean age was 63.1 ± 12.8 years, 73.9% were men and 74.3% were in Killip I. 98.5% received an antiaggregant load of aspirin, 56.7% one of ticagrelor and 41.6% clopidogrel.

Failed TA patients were older, presented worse Killip classification and were more often pre-treated with ticagrelor. When looking at angiographic characteristics, there was a higher proportion of culprit lesions in arteries other than the anterior descending, as well as more moderate to severe tortuosity (12.9% vs. 7.3%; P = 0.009) and moderate to severe calcification (12.9% vs. 8.3%; P = 0.035).

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In patients with successful TA, 12.8% presented thrombus grade 3 (G-3) or moderate (0.5-2.0 x vessel diameter), 82.7% G-4 or large (>2 x diameter) and 4.5% G-5 or total occlusion. When looking at primary end point, TIMI flow resulted 0-2 in 25.4% of the failed group, 17.6% of the TA group with successful TA (OR: 1.594; CI 95%: 1.124-2.261; P = 0.009). Myocardial blush was 0-1 in 19.7% of the failed TA group and 13.7% of the successful group (OR: 1.547; CI 95%: 1.053-2.273; P = 0.026). The failed TA group showed higher incidence of microvascular obstruction and brighter CMR. Also, all-cause mortality (11.8% vs. 7.1%; P = 0.024) and cardiovascular death rates (11.1% vs. 6.4%; P = 0.018) were higher among failed TA patients.

Predictors of reduced TIMI flow and failed TA were ≥75 years (OR: 1.753; CI 95%: 1.138-2.701; P = 0.011), ischemic time >230 minutes (OR: 1.677; CI 95%: 1.151-2.445; P = 0.007) and failed TA (OR: 1.525; CI 95%: 1.048-2.218; P = 0.027).

CONCLUSIONS

≥75 years, higher Killip, and anatomical characteristics such as tortuosity and calcification, as well as location other than the anterior descending, were identified as independent predictors of failed TA. Also, failed TA is associated to inadequate perfusion, evidenced by lower final TIMI flow grade. 

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

Reference: Jeon, H, Kim, Y, Lee, J. et al. Failed Thrombus Aspiration and Reduced Myocardial Perfusion in Patients With STEMI and Large Thrombus Burden. J Am Coll Cardiol Intv. null2024, 0 (0) . https://doi.org/10.1016/j.jcin.2024.07.016.