Anticoagulation Therapy Often Poorly Managed in Pulmonary Arterial Hypertension

PT INR test
PT INR test
A study evaluated the quality of targeted anticoagulation in patients with PAH, and examined outcomes associated with poor time spent within targeted anticoagulation range.

Patients with pulmonary arterial hypertension (PAH) often have low quality of target anticoagulation and as a result may be at higher risk for anticoagulation-related complications, according to a study published in Thrombosis Research.

Researchers collected data retrospectively on a cohort of 121 patients with PAH currently taking oral anticoagulation therapy who were receiving treatment at Brigham and Women’s Hospital in Boston, Massachusetts, and Hospital Universitario L Paz in Madrid, Spain. Patients in Boston were more commonly prescribed warfarin, while acenocoumarol was the vitamin K antagonist of choice by clinicians in Madrid.

The objectives of this study were to assess the quality of the anticoagulation management, the rate of complications related to anticoagulation, and the risk factors for poor anticoagulation in patients with PAH.

Only 57% of individuals on oral anticoagulant treatment were in time spent within range (TTR), with a reported 105 anticoagulation-related complications in 47 individuals.

The odds ratio of having an anticoagulation-related event was 2.43 in patients with TTR <60% (95% CI, 1.01-5.83; P =.046). Thrombosis rates were significantly higher in individuals with TTR <60% (1.5 events per 100 patient-years) than those with TTR >60% (0.6 events per 100 patient-years) (95% CI, 0.02-3.4). Potential predictors for poor anticoagulation were found to be age, sex, functional capacity, atrial fibrillation, and select PAH medications.

Overall, investigators found inconsistent control of the International Normalized Ratio (INR) in patients with PAH, with a strong association between poorly controlled anticoagulation therapy and anticoagulation-related complications.

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They concluded that patients on oral anticoagulation medications with TTR <60% experienced more anticoagulation-related events and were noted to be in the therapeutic range less than two-thirds of the time (57%). This is below the national average TTR in anticoagulation clinics (69%), suggesting that patients with PAH may be a more challenging population in whom to manage anticoagulation therapy.

Individuals with PAH found to have the best INR control were at centers that specifically manage anticoagulation therapy in individuals. Therefore, clinicians should carefully monitor INR in patients diagnosed with PAH and refer them for careful management at an anticoagulation specializing center whenever possible.


Roldan T, Villamañán E, Rios JJ, Waxman AB. Assessment of the quality of anticoagulation management in patients with pulmonary arterial hypertension. Thromb Res. 2017;160:83-90.