• Cardiology Clinical Trials
• Interventional Techniques & Devices
• Thrombotic Disorders

• Cardiology Clinical Trials
• Cardiology & Cardiovascular Medicine
• Interventional Techniques & Devices
• Thrombotic Disorders

Adeel Shahzad, PhD, Liverpool Heart and Chest Hospital, Liverpool, United Kingdom (UK), presented results from the How Effective Are Antithrombotic Therapies in Primary Percutaneous Coronary Intervention trial [HEAT PPCI; NCT01519518]. All patients with ST-segment elevation myocardial infarction presenting at a single UK center were randomized to open-label treatment with heparin (70 units/kg body weight preprocedure) or bivalirudin (bolus of 0.75 mg/kg followed by 1.75 mg/kg/hour infusion during the procedure) on top of preprocedure dual antiplatelet therapy. The glycoprotein IIb/IIIa inhibitor, abciximab, was available for “bailout” from ischemic complications in both groups. Patients were excluded if they had active bleeding at presentation; administration of oral antiplatelet therapy was contraindicated, had a known intolerance or contraindication to the study medications, or had previously enrolled in the study.

The study protocol received full UK ethics approval and both drugs were administered according to the approved labeling. The ancillary benefit of this consent approach was to improve generalizability of the study results by allowing for enrollment of subjects that would not typically be included. The primary efficacy endpoint was major adverse cardiac events (MACE) at 28 days. Major bleeds, defined as Type 3 to 5 per the Bleeding Academic Research Consortium definitions, was the primary safety endpoint. A clinical events committee blinded to treatment assignment adjudicated key clinical events.

Over a 22-month period, 1917 patients presented for emergency angiography and 1829 eligible patients were randomized. Only seventeen patients did not give informed consent after the acute intervention. Of those randomized, 905 were in the bivalirudin analysis and 907 were analyzed from the heparin group. The demographic characteristics were similar between the two treatment groups. The median age was ∼63 years, ∼27% were female, and >95% were Caucasian. Approximately 12% of patients had a previous MI. Procedural details are presented in Table 1.

Event rates by treatment group are presented in Table 2. For the primary efficacy outcome, MACE was 8.7% (n=79) in the bivalirudin group compared with 5.7% (n=52) in heparin-treated patients, resulting in an absolute risk difference of 3.0% and a relative risk ratio (RRR) of 1.52 (95% CI, 1.1 to 2. 1; p=0.01). The risk of stent thrombosis was higher with bivalirudin (3.4% [n=24] vs 0.9% [n=6], RRR, 3.91; 95% CI, 1.6 to 9.5; p=0.001). Safety was similar between the two groups for the primary safety outcome of major bleeds. Thirty-two bivalirudin-treated patients (3.5%) had a major bleed compared with 28 patients receiving heparin (3.1%; RR, 1.15; 95% CI, 0.7 to 1.9; p=0.59).

Although the trial was large, it was conducted at a single center and with open-label therapy. Dr. Shahzad noted that the large sample size and unselected population with multiple operators made this a “real world” trial. The investigators believe that the potential impact of the open-label design, which has been utilized in other trials, was mitigated by complete follow-up (no loss to follow-up), a primary outcome of overt clinical events, and adjudication by independent blinded clinicians.

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