Higher Heparin Dose Doesn't Cut Stent Risks
Patients getting elective stents saw no drop in death, heart attack, or repeat procedures with a higher heparin bolus.
Updated on Nov. 2, 2026 in Heart Disease
A large cluster-randomised trial presented at the TCT 2026 meeting found that a higher heparin dose during elective coronary stenting did not reduce death, heart attack, or repeat revascularisation compared with a standard lower dose. Major bleeding rates were similar in both groups, so the study does not support switching to the higher dose for this procedure.
Why it matters
Heparin is a routine anticoagulant given during percutaneous coronary intervention (PCI), and dosing has been debated for years. The HD-PCI results give clinicians and patients evidence that increasing the dose did not improve 30-day outcomes, though the trial enrolled fewer patients than planned and lacked routine post-procedure biomarker data.
This cluster-randomised, crossover, registry-based trial enrolled 11,619 patients undergoing elective PCI at 11 hospitals, comparing a 100 U/kg heparin bolus with a 70 U/kg bolus. The 30-day composite of death, heart attack, or repeat revascularisation was 1.2% with the higher dose and 1.0% with the lower dose, a difference that was not statistically significant (P = .17).
The players
McMaster University
A research university in Hamilton, Ontario, whose investigators lead cardiovascular trials in interventional cardiology.
The details
Heparin is an anticoagulant that prevents clots from forming during and after the balloon-and-stent procedure used to open narrowed coronary arteries. In HD-PCI, hospitals alternated between two standard policies, giving patients either a 70 U/kg or a 100 U/kg intravenous heparin bolus. The higher bolus produced more deeply anticoagulated blood, but in this trial that extra anticoagulation did not translate into fewer ischaemic events or more bleeding. Exploratory measurements showed activated clotting time (ACT) values below 250 seconds were less common with the higher dose at two centres, though this finding was not tied to clinical outcomes.
Timeline
November 2, 2026: HD-PCI results presented at the TCT 2026 meeting
Health Landscape
Anticoagulation during PCI has long relied on fixed weight-based heparin dosing set by prior practice rather than head-to-head outcome data. Pragmatic cluster-randomised designs like HD-PCI are increasingly used to test whether routine dosing choices change patient outcomes in everyday cardiac care.
If you are scheduled for an elective stent procedure, the findings suggest a standard heparin dose is not inferior to a higher one for 30-day outcomes, which is worth raising with your cardiologist. Questions about your own anticoagulation plan are best answered by your treating physician, who can weigh these results against your individual risks.
The takeaway
A higher heparin bolus did not improve 30-day outcomes or increase major bleeding in elective PCI, so the standard dose remains a reasonable choice. Ask your cardiologist how anticoagulation is managed during any planned stent procedure.
Further reading
For more on how doctors manage heart disease and procedures like stenting, explore our Heart Disease coverage.
