TCT-855 Optical coherence tomography appraisal of residual thrombus burden in patients with ST-segment elevation myocardial infarction undergoing high versus low bivalirudin infusion. The MATRIX (Minimizing Adverse Haemorrhagic Events by TRansradial Access Site and angioX) OCT study

BACKGROUND Residual stent strut thrombosis, which is frequently documented after primary PCI, may increase stent thrombosis risk and prevents optimal myocardial perfusion. Objectives: to assess whether a strategy of either high dose (HB) versus low dose (LB) bivalirudin infusion reduces residual stent strut thrombosis in sub- jects with ST elevation myocardial infarction (STEMI). M E T H O D S Multivessel STEMI patients undergoing primary PCI and requiring staged intervention were selected among those allocated to either HB (1.75 mg/kg/h) or LB (0.25 mg/kg/h) in the MATRIX (Minimizing Adverse Haemorrhagic Events by TRansradial Access Site and angioX) Treatment- Duration study. Optical coherence tomography (OCT) of the infarct-related artery was performed at the end of primary PCI and four to five days thereafter during staged intervention. The primary endpoint was the change in minimum flow area (DMinFA) defined as: [stent area þ incom- plete stent apposition (ISA) area] - (intraluminal defect þ tissue prolapsed area) between index and staged PCI. RESULTS Between September 2013 and November 2015, 316 patients were screened and 64 received either LB (N1⁄441) or HB (N1⁄473). Mean stent and lumen areas, percentage of malapposed struts and mean percent thrombotic area were comparable after index or staged PCI. DMinFA [LB: 0.25 (0.03, 0.70) and HB 0.39 (-0.01, 0.88) mm2; P1⁄40.894]. CONCLUSION Prolonged bivalirudin infusion with either high or low dose after primary PCI did not reduce residual stent strut thrombosis. This observation should be considered hypothesis generating since treatment was not randomly allocated.