Are Clot Busters Acceptable for Stroke Patients on Anticoagulation?

May 29th, 2018

Based on treatment guidelines, emergency clinicians sometimes are hesitant to use IV tissue plasminogen activator (tPA) in stroke patients on anticoagulation therapy. Yet research discussed at the International Stroke Conference earlier this year indicates that being on anticoagulants should not prohibit tPA use in acute ischemic stroke patients, study authors determined.

Novel oral anticoagulants (NOAC) are increasingly used as an alternative to warfarin to reduce stroke risk in atrial fibrillation patients. But if those patients are diagnosed with ischemic strokes, guidelines recommend against the use of tPA unless sensitive coagulation parameters are normal or 48 hours has passed since the last dose.

The team involved in this recent study, led by University of California San Diego researchers, wanted to determine the relationship between anticoagulation use and hemorrhagic conversions (HC) in patients treated with IV tPA in a large and representative national patient registry.

“Even though [tPA] has unequivocally shown to improve outcomes in acute ischemic stroke (AIS), its utilization remains low due to various concerns/contraindications. Many clinicians are concerned about the risk of hemorrhage after tPA in patients on anti-coagulation (AC),” researchers wrote.

Their study was based on an analysis of the National Inpatient Sample and Healthcare Cost and Utilization Project data for years 2002-2014. AIS was identified with ICD-9-CM codes 433.xx-436, IV tPA with procedure code 99.10, and HC with ICD-9 431. Concurrently, anticoagulation use was documented by previously validated ICD-9-CM codes.

Data indicated that 264,643 patients with AIS received IV tPA, of which 12,690 were on AC prior to admission.

While unadjusted, the frequency of HC was higher among AC group (9.1% vs. 8.0%; P < 0.001), yet the difference disappeared after adjusting for confounders with multivariate analysis. Researchers found no difference in HC between the groups on AC and not on blood-thinners (OR, 0.87; 95% CI, 0.75-1.01; P = 0.071).

The authors also detected no variation in in-hospital mortality (OR, 0.91; 95% CI, 0.79-1.05; P = 0.178) or discharge to home (OR, 1.1; 95% CI, 0.99-1.2; P = 0.05) among the AC vs. “not on AC” groups.

“Our study shows AC use prior to AIS onset is not associated with higher HC with tPA use,” study authors concluded. “Moreover, no significant differences in outcomes were observed in AC and ‘not on AC’ group. Being on AC should not be a prohibitive factor for tPA utilization in AIS patients. Further prospective studies that include precise anticoagulant measurements are required to better understand the relationship between AC use and HC.”

Limitations of the study included that it was based on registries that do not include decision-making details about IV tPA use or the timing of the anticoagulation.