Purpose
Evaluate the characteristics of patients started on intravenous heparin for a thrombotic indication that experienced PTT prolongation at Jefferson Einstein Philadelphia Hospital.
Methods
This study included patients at least 18 years old that received heparin for a thrombotic indication and had at least 48 hours of PTTs available in their chart. Prolonged PTT was defined by two or more PTT values greater than 112 seconds within 48 hours of heparin. If patients experienced a prolonged PTT, they were evaluated to determine if a bleeding event had occurred within 48 hours of heparin. Patients were excluded if they were pregnant at data collection. The primary endpoint was a multivariable analysis of characteristics that predisposed patients to prolonged PTTs, including hypertension, abnormal renal and/or liver function, previous stroke, history of bleed, baseline PTT 1.5 times the upper limit of normal, age, alcohol use disorder, body mass index, male sex, bolus on initiation, black race, and thrombolytic or anticoagulant use within 48 hours of heparin initiation. The secondary endpoint was the incidence of bleeding with prolonged PTT.
Results
Data was analyzed using GraphPad Prism 10.6.1. Out of 344 patients, 58 (16.9%) did not experience PTT prolongation. Baseline characteristics between both groups were similar. PTT 1.5 times the upper limit of normal (5.8, 95% CI [1.1-107], p=0.04) was the only variable associated with PTT prolongation. All other variables were considered statistically nonsignificant. Among the 286 patients
(83.1%) that experienced PTT prolongation, 65 patients (22.7%) experienced a bleeding event within 48 hours of heparin initiation.
Conclusion/Summary
This study with 344 patients found that a baseline PTT 1.5 times the upper limit of normal is associated with PTT prolongation. Limitations include single-center, retrospective nature, and small sample size. Future steps include conducting a study using a nomogram with conservative heparin dosing in this cohort of patients with PTT prolongation at baseline and more frequent monitoring to prevent adverse outcomes.
