Approximately two-thirds of all PCI are performed for acute coronary syndromes.  In this setting, the optimal balance of anticoagulation to avoid thrombosis against the risk of major bleeding is a pivotal area of procedural management.  Multiple clinical trials have compared bivalirudin and heparin (+/- IIb/IIIa inhibitor), but the optimal strategy remains debated.  In particular, changes in clinical practice, namely increasing use of radial access and decreasing use of IIb/IIIa inhibitors, may influence the optimal antithrombotic treatment strategy.  In the MATRIX trial, 7213 patients with an acute coronary syndrome (55% with ST-elevation) were randomly allocated to receive either bivalirudin or heparin at 70-100u/kg peri-procedurally with an additional randomization step at procedural completion to either stop bivalirudin or continue the infusion for 4 to 6 hours.  Approximately 25% of the heparin group also received a IIb/IIIa inhibitor at the treating physician’s discretion.  There was no significant difference in rates of major adverse cardiovascular events between the bivalirudin and heparin groups (10.3% vs. 10.9%; RR, 0.94; 95% CI, 0.81 to 1.09; P=0.44), nor was there any difference in safety outcomes between the two arms (P=0.12).  In addition, prolonging bivalirudin infusion made no difference to clinical outcomes with no change in rates of stent thrombosis or other adverse clinical events (P=0.34).

Conclusions

In this latest study of bivalirudin versus heparin, there was no difference in outcomes between the two drugs among patients undergoing PCI for acute coronary syndromes. Prior studies suggest bleeding events may be lower with bivalirudin as compared with heparin.  However, with increasing use of radial access and decreasing use of IIb/IIIa in routine practice, the relative benefit of bivalirudin may be decreasing and contribute to the findings of recent trials.

Summarized by Hussain Contractor and Steven M. Bradley

Valgimigli M, Frigoli E, Leonardi S, Rothenbühler M, Gagnor A, Calabrò P, Garducci S, Rubartelli P, Briguori C, Andò G, Repetto A, Limbruno U, Garbo R, Sganzerla P, Russo F, Lupi A, Cortese B, Ausiello A, Ierna S, Esposito G, Presbitero P, Santarelli A, Sardella G, Varbella F, Tresoldi S, de Cesare N, Rigattieri S, Zingarelli A, Tosi P, van ‘t Hof A, Boccuzzi G, Omerovic E, Sabaté M, Heg D, Jüni P, Vranckx P; MATRIX Investigators. Bivalirudin or Unfractionated Heparin in Acute Coronary Syndromes. N Engl J Med. 2015 Sep 10;373(11):997-1009.