We’ve been routinely starting anticoagulation therapy on patients diagnosed with an acute coronary syndrome for a couple decades. The evidence from the preceding era is clear – patients treated with anticoagulation plus aspirin are at much lower risk for subsequent ischemic events than those treated with aspirin alone.
However, these trials are not generalizable to most modern care for ACS. For example, the FRISC and ATACS trial discharged patients with nSTEMI or unstable angina with continued anticoagulation for weeks to months. Revascularization procedures were performed only as rescue therapy, rather than the routine early invasive strategies in use today. Dual anti-platelet and other adjunctive therapies were unavailable. So – do we actually still need the heparin?
These authors retrospectively evaluated the association between parenteral anticoagulation therapy and in-hospital death and in-hospital major bleeding. There were 6,804 patients included in their 4-year, multi-center data set, about two-thirds of whom did not receive parenteral anticoagulation prior to PCI. There were small, probably unimportant differences reported between groups, excepting one feature: time to intervention. Time to intervention was a median of 1 day in those managed without anticoagulation versus a median of 3 days in those managed with. Overall, there was no difference in in-hospital death, nor 30-day, 1-year, or 3-year death for those included in long-term follow-up. A handful of cases suffered bleeding complications, with a small absolute excess in those managed with anticoagulation.
This is neither prospective nor a randomized trial, and there could certainly be unexamined confounding baseline characteristics favoring one treatment group over the other. The authors also note bleeding complications could be ameliorated by use of fondaparinux rather than heparinoids, but this would still be moot if there is still no benefit to anticoagulation. Finally, in-hospital mortality is a fabulous patient-oriented endpoint, but it does not tell the entire story with regard to any additional morbidity potentially resulting from anticoagulation being withheld. We should not change practice based on this level of evidence, but these data should prompt further examination and potentially prospective evaluation.
“Association of Parenteral Anticoagulation Therapy With Outcomes in Chinese Patients Undergoing Percutaneous Coronary Intervention for Non–ST-Segment Elevation Acute Coronary Syndrome”
https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2719425