MATRIX Trial Compares Radial and Femoral Access for PCI
March 18, 2017—Alessandro Sciahbasi, MD, revealed findings from the MATRIX study during a featured clinical research presentation at ACC.17, the American College of Cardiology's 66th annual scientific session in Washington, DC.
This study of minimizing adverse hemorrhagic events by transradial access site with systemic implementation of AngioX (bivalirudin, The Medicines Company) compares radial access (using Terumo devices) with femoral access among patients undergoing cardiac catheterization for acute coronary syndromes. The trial is sponsored by The Medicines Company and Terumo.
The ACC outlined the trial design in an abstract that noted that the randomized, parallel, blinded, and stratified trial enrolled 8,404 patients with acute coronary syndromes (ST-segment elevation myocardial infarction [STEMI; 48%)] and non-STEMI [NSTEMI; 52%]). The mean age of patients was 66 years; 25% were female; 23% had diabetes.
Patients were randomized to radial access (n = 4,197) versus femoral access (n = 4,207). By factorial design, patients were also randomized to bivalirudin versus heparin (reported separately).
Percutaneous coronary intervention (PCI) was attempted in 80% of patients. Anticoagulation administered in the catheterization lab was unfractionated heparin in 50% of patients and bivalirudin in 40%. Attempted access was unsuccessful 5.8% of the radial group versus 2.3% of the femoral group.
At 30-day follow-up, the findings showed that radial access for acute coronary syndromes was associated with reduced net adverse events compared with femoral access.
As summarized in the ACC abstract, the primary outcome of death, myocardial infarction, or stroke occurred in 8.8% of the radial group versus 10.3% of the femoral group (P = .031), which exceeded the prespecified α level of 2.5%. The only subgroup in which there was evidence of treatment interaction was the hospital’s radial PCI volume; hospitals that performed > 80% radial PCIs had better outcomes with radial procedures versus femoral procedures (P for interaction = .0048). Hospitals with a low and intermediate proportion of radial PCIs had similar outcomes with either radial or femoral procedures.
Secondary outcomes for radial versus femoral included death, MI, stroke, or BARC (type 3 or 5) major bleeding (9.8% vs 11.7%; P = .0092); all-cause mortality (1.6% vs 2.2%; P = .045); stroke (0.4% vs 0.4%; P = .99); and Bleeding Academic Research Consortium type 3 or 5 major bleeding (1.6% vs 2.3%; P = .0128).
In a subset of patients enrolled in the RAD-MATRIX study (n = 7,570) evaluating radiation exposure, the mean thorax radiation dose to the operator was 77 µSv for radial procedures versus 41 µSv for femoral procedures (P = .019). The effective dose delivered to the patient was 13 µSv for radial procedures versus 12 µSv for femoral procedures (P < .0001).
In an interpretation of the study findings for the ACC, reviewer Deepak Bhatt, MD, stated, "Among patients with acute coronary syndromes, radial access for cardiac catheterization was associated with a reduction in net adverse cardiovascular events compared with femoral access. Although there was a favorable trend toward reduction in major adverse cardiovascular events, this coprimary endpoint did not reach formal statistical significance."
Dr. Bhatt continued, "Radial access was associated with greater radiation to the operator and the patient. Benefit was most pronounced among the highest volume radial PCI centers (ie, > 80% PCIs by radial access). This suggests that for catheterization laboratories that are facile with femoral access with low bleeding rates, benefit from radial access may be marginal. For catheterization laboratories that have high rates of bleeding with femoral access, conversion to default radial access would be an appropriate mechanism to reduce bleeding and net adverse events. Operators who perform radial procedures need to remain vigil about reducing radiation exposure to patients."