Valgimigli M, et al. - Researchers described the prespecified final 1-year outcomes of the Minimizing Adverse Haemorrhagic Events by Transradial Access Site and Systemic Implementation of Angiox (MATRIX) programme. In this programme, patients with the whole spectrum of acute coronary syndrome undergoing invasive management were included to assess the comparative safety and effectiveness of radial vs femoral access and of bivalirudin vs unfractionated heparin with optional glycoprotein IIb/IIIa inhibitors. They noted lower rates of net adverse clinical events, but no major adverse cardiovascular events at 1 year, in association with radial access vs femoral access. Lower rates of major adverse cardiovascular events or net adverse clinical events were not evident in association with bivalirudin with or without post-procedure infusion. For acute coronary syndrome patients undergoing invasive management, radial access should become the default approach.

Methods

• MATRIX was a programme of three nested, randomised, multicentre, open-label, superiority trials in patients with acute coronary syndrome.
• The programme was conducted at 78 hospitals in Italy, the Netherlands, Spain, and Sweden.
• Simultaneous random assignment (1:1) was performed of patients with ST-elevation myocardial infarction before coronary angiography to radial or femoral access and to bivalirudin, with or without post-percutaneous coronary intervention infusion or unfractionated heparin (one-step inclusion).
• Researchers randomly assigned (1:1) patients with non-ST-elevation acute coronary syndrome before coronary angiography to radial or femoral access and, only if deemed eligible to percutaneous coronary intervention after angiography (two-step inclusion), the patients were included in the antithrombin type and treatment duration programmes.
• Using computers, they generated, blocked, and stratified the randomisation sequences in accordance to intended new or current use of P2Y12 inhibitor (clopidogrel vs ticagrelor or prasugrel), and acute coronary syndrome type (ST-elevation myocardial infarction, troponin-positive, or troponin-negative non-ST-elevation acute coronary syndrome).
• They provided bivalirudin as a bolus of 0·75 mg/kg, followed immediately by an infusion of 1·75 mg/kg per h until completion of percutaneous coronary intervention.
• They administered heparin at 70–100 units per kg to patients not receiving glycoprotein IIb/IIIa inhibitors, and at 50–70 units per kg to patients receiving glycoprotein IIb/IIIa inhibitors.
• They performed clinical follow-up at 30 days and 1 year.
• For MATRIX access and MATRIX antithrombin type, co-primary outcomes included major adverse cardiovascular events, defined as the composite of all-cause mortality, myocardial infarction, or stroke up to 30 days; and net adverse clinical events, defined as the composite of non-coronary artery bypass graft-related major bleeding, or major adverse cardiovascular events up to 30 days.
• The composite of urgent target vessel revascularisation, definite stent thrombosis, or net adverse clinical events up to 30 days was assessed as the primary outcome for MATRIX treatment duration.
• The intention-to-treat principle was used to perform the analyses. 

Results

• Researchers performed a random assignment of 8404 patients to receive radial (4197 patients) or femoral (4207 patients) access between Oct 11, 2011, and Nov 7, 2014.
• The MATRIX antithrombin type study included 7213 of these 8404 patients; these patients randomly received bivalirudin (3610 patients) or heparin (3603 patients).
• The MATRIX treatment duration study included patients assigned to bivalirudin; these patients were randomly assigned to post-procedure infusion (1799 patients) or no post-procedure infusion (1811 patients).
• At 1 year, patients assigned to radial access and those assigned to femoral access were not different regarding the major adverse cardiovascular events (14·2% vs 15·7%; rate ratio 0·89, 95% CI 0·80–1·00; p=0·0526), however, fewer net adverse clinical events were observed with radial than with femoral access (15·2% vs 17·2%; 0·87, 0·78–0·97; p=0·0128).
• Compared with heparin, no association of bivalirudin with fewer major adverse cardiovascular (15·8% vs 16·8%; 0·94, 0·83–1·05; p=0·28) or net adverse clinical events (17·0% vs 18·4%; 0·91, 0·81–1·02; p=0·10) was evident.
• Researchers identified no differences in the composite of urgent target vessel revascularisation, stent thrombosis, or net adverse clinical events with or without post-procedure bivalirudin infusion (17·4% vs 17·4%; 0·99, 0·84–1·16; p=0·90).