Incidence of thromboembolic complications in patients with atrial fibrillation or mechanical heart valves with a subtherapeutic international normalized ratio: a prospective multicenter cohort study

Francesco Dentali, Pasquale Pignatelli, Alessandra Malato, Daniela Poli, Matteo Nicola Dario Di Minno, Leonardo Di Gennaro, Elena Rancan, Daniele Pastori, Elisa Grifoni, Elena Grifoni, Alessandro Squizzato, Sergio Siragusa, Giovanni Di Minno, Walter Ageno
American Journal of Hematology 2012, 87 (4): 384-7
Subtherapeutic international normalized ratio (INR) is frequently encountered in clinical practice, and patients with high-risk atrial fibrillation (AF) and with mechanical heart valve (MHV) with inadequate anticoagulation may be exposed to an increased risk of thromboembolic events (TE). However, there are no prospective data evaluating this risk. Consecutive patients with a history of stable anticoagulation, but with a subtherapeutic INR, were prospectively included. Data on use and dose of low-molecular weight heparin (LMWH) bridging therapy were collected. The incidence of objectively confirmed TE and of major bleeding events within 90 days after the index INR was assessed. Five hundred and one patients with INR value 0.5-1 INR units below the lower limit of the patient-specific target INR were included in the study (280 with MHV and 221 with AF and CHADS2 score ≥3). LMWH was prescribed for 64 patients (12.8%). During follow-up, seven patients had a TE (1.40%; 95% confidence interval 0.68, 2.86%; 5.58 events for 100 patients year). All the events occurred within 14 days after the index INR. When we consider only patients who did not receive bridging therapy, the incidence of TE was 1.14% (5 of 437 patients; 95% confidence interval 0.49, 2.64%; 4.58 events for 100 patients year). There were no major bleeding events. The risk of TE in this population was not negligible. Given the frequent observation of subtherapeutic INR levels when monitoring vitamin K antagonists, this finding warrants additional investigation to improve the management of these patients.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"