Updates on thrombectomy for PCI in STEMI
Thrombectomy is known to improve myocardial reperfusion in ST-elevation myocardial infarction (STEMI), but no mortality benefit has been clearly demonstrated with this strategy, according to a presentation at APSC 2017, which suggests that thrombus aspiration in primary percutaneous intervention (PCI) should not be a routine procedure.
“Thrombectomy should be reserved for cases with large thrombus burden, or [as a] bailout for residual thrombus or slow/no-reflow [phenomenon],” suggested Dr Choo Gim Hooi from the Cardiac Vascular Sentral Kuala Lumpur, Malaysia.
The latest ACC/AHA/SCAI update (2015) on guideline for primary PCI in patients with STEMI states that “routine aspiration thrombectomy before primary PCI is not useful (level of evidence: A)” and gives it a “class III recommendation”, which indicates no benefit. Recommendation for selective and bailout aspiration thrombectomy before PCI has also been modified from class “IIa” in 2011/2013 to “IIb” in the latest update, stating that the usefulness of such procedure “is not well established.” [Circulation 2016;133:1135-1147]
The initial enthusiasm for aspiration thrombectomy was rekindled in 2008 with the publication of the TAPAS* trial, which showed that thrombus aspiration before stenting an infarcted artery reduced cardiac death at 1 year (hazard ratio [HR], 1.93; p=0.02) and the combined cardiac death or nonfatal reinfarction at 1 year (HR, 1.81; p=0.009) compared with conventional PCI for STEMI. [Lancet 2008; 371:1915-1920]
“Although aspiration thrombectomy [is a] slightly more time-consuming procedure [than PCI alone, it] may facilitate better lesion visualization, appropriate stent selection, and direct stenting,” said Choo.
However, the TASTE** trial which involved 7,244 patients with STEMI undergoing PCI revealed no reduction in all-cause mortality at 30 days (HR, 0.94; p=0.63) or 1 year (HR, 0.94; p=0.57) with routine thrombectomy vs PCI alone. [N Engl J Med 2014;371:1111-1120]
In the TOTAL*** study, not only was there no reduction in the risk of the composite primary endpoint of cardiovascular (CV) death, cardiogenic shock, recurrent myocardial infarction, or NYHA# class IV heart failure at 6 months after thrombectomy compared with PCI alone (HR, 0.99; p=0.86), there was an increased stroke rate within 30 days after thrombectomy (HR, 2.06; p=0.02). [N Engl J Med 2015;372:1389-1398]
Nonetheless, the stroke risk in the TOTAL trial needs to be confirmed in future studies, cautioned Choo.
“Although thrombectomy improves myocardial reperfusion in STEMI, no mortality benefit has been observed with this strategy,” he said, underscoring the updated recommendation in clinical guideline that thrombectomy should not be a routine procedure in primary PCI.
Still, he questioned, “do you need mortality benefit before you decide whether to remove aspiration catheters from your cath lab?” and “are there subsets that may still have improved clinical outcomes with aspiration thrombectomy?”
In a meta-analysis from the Thrombectomy Trialists Collaboration, which pooled data from the TAPAS, TASTE, and TOTAL studies, CV death (HR, 0.84; p=0.06) and stroke or transient ischaemic attack (TIA) within 30 days (HR, 1.43; p=0.06) were not significantly different between the thrombectomy group vs the PCI alone group. However, subgroup analysis of patients with high thrombus burden (TIMI## grade ≥3) showed fewer CV deaths with thrombus aspiration (HR, 0.80; p=0.03), albeit with more strokes or TIA (odds ratio, 1.56; p=0.04). [Circulation 2017;135:143-152]
As such, aspiration thrombectomy should be reserved for patients with high thrombus burden or as a bailout, Choo said, adding that “if thrombus aspiration is deemed necessary but not possible/ineffective, other options of thrombus management … [available include using] other mechanical thrombectomy devices, embolic protection stents, or pharmacological drugs.”
“I still have space in my cath lab shelf for thrombectomy catheters,” he said.