PARIS—New research suggests that patients who have undergone primary percutaneous coronary intervention (PCI) have a low risk of stent thrombosis, regardless of the anticoagulant therapy they receive.
In a large, registry-based study, stent thrombosis occurred in less than 1% of patients, regardless of whether they received bivalirudin with or without heparin, heparin alone, or a GP IIb/IIIa inhibitor (GPI) with or without heparin.
The study also showed that patients who experienced stent thrombosis between days 2 and 30, regardless of drug regimen, were more likely to die within a year than patients who developed stent thrombosis within the first 24 hours of their procedure.
Per Grimfjard, of Vasteras Hospital/Uppsala University in Sweden, presented these findings at EuroPCR 2015.
A number of recent studies have raised concerns that bivalirudin may increase the risk of stent thrombosis compared with heparin. But rates of stent thrombosis have differed substantially between studies.
So Dr Grimfjard and his colleagues decided to review stent thrombosis rates by drug choice among more than 30,000 patients who were treated with primary PCI for ST-elevation myocardial infarction (STEMI) between January 2007 and July 2014 in the Swedish Coronary Angiography and Angioplasty Register (SCAAR).
The researchers divided patients into 3 treatment groups: bivalirudin, heparin, and GPI. However, 77% of patients in the bivalirudin group also received heparin, and 3.6% received a GPI prior to or during the PCI procedure. In the GPI group, 77% of patients also received heparin.
The rates of stent thrombosis were low in all 3 groups—0.84% in the bivalirudin group, 0.94% in the heparin group, and 0.83% in the GPI group.
For all 3 drugs, mortality at 1 year was numerically higher if the stent thrombosis occurred between 2 and 30 days, as compared with day 0 to 1 post-PCI.
“[A] possible explanation is that a stent thrombosis that happens once the patient has left the hospital is likely to cause a more substantial infarction, the reason being longer delay from symptoms to revascularization,” Dr Grimfjard said.
He added that a more substantial myocardial infarction typically leads to more heart failure and arrhythmia long-term. Unfortunately, the findings regarding the timing of stent thrombosis do not offer any guidance for choosing optimal antithrombotic treatment.
He and his colleagues are currently enrolling patients in a 6000-patient, registry-based, randomized clinical trial called SWEDEHART-Validate. The team will compare heparin alone to bivalirudin and optional low-dose heparin in STEMI and non-STEMI patients undergoing PCI.
“Hopefully, this large, randomized trial will bring clarity to the choice of antithrombotic treatment strategy in these patients,” Dr Grimfjard said.
