Current Guidelines
Both the current European Society of Cardiology (ESC) and American College of Cardiology/American Heart Association (ACC/AHA) guidelines recommend coronary artery thrombus aspiration as adjunctive therapy during primary PCI for STEMI.48,49 These recommendations are based partly on TAPAS30 together with several meta-analyses,37,39 which provided the necessary evidence to endorse thrombus aspiration as a class IIa recommendation with the level of evidence B in the ACC/AHA guideline48 and with level of evidence A in the ESC guidelines.49 Whether the recent data should change this is much debated. Thrombus aspiration clearly has a role to play but perhaps the routine use is not the answer. Instead, the use of thrombectomy should probably be limited to cases of poor pre-procedural reperfusion or in cases where there is evidence of large intracoronary thrombus burden.
The Future
Due to the uncertainty of the use of thrombectomy in PPCI for STEMI, a number of large multi-centre clinical trials are currently taking place, which will hopefully provide a more definite answer to whether the use of thrombectomy is associated with a clinical benefit in this setting. Further evidence regarding routine use should be provided by the large multi-centre trial to date investigating the role of manual aspiration thrombectomy using the Export catheter (A Trial of Routine Aspiration Thrombectomy With PCI Versus PCI Alone in Patient with STEMI Undergoing Primary PCI [TOTAL]) is aiming to recruit 4,000 patients. Primary composite endpoints are cardiovascular death, recurrent MI, cardiogenic shock, or new or worsening New York Heart Association (NYHA) Class IV heart failure up to 180 days.50
A direct comparison between manual and mechanical will be provided by the Comparison of Manual Aspiration With Rheolytic Thrombectomy in Patients Undergoing Primary PCI (SMART-PCI) trial. This is a singlecentre study that is directly comparing the role of mechanical versus manual thrombectomy in PPCI.47,51 The primary endpoint is residual thrombus burden assessed as number of coronary quadrants containing thrombus by optical coherence tomography (OCT) after thrombectomy and before infarct artery stenting. Their preliminary results suggest that mechanical thrombectomy has better STR, TIMI 3 flow and TIMI grade 3 blush compared with manual thrombectomy.51 However, this study is not powered to investigate any long-term clinical benefits of thrombectomy.
Finally, a large ongoing trial in Korea including 27 centres is comparing PPCI using thrombectomy with PPCI alone. They are aiming to recruit 1,400 patients in total with a primary endpoint of cardiac death and MI at 12 months after their procedure.52
Although one cannot be certain whether these trials will provide a definitive answer regarding the use of thrombectomy in PPCI for STEMI, they will hopefully add clarity to the long-term benefits of their use.