Factors associated with thrombotic complications after the Fontan procedure: a secondary analysis of a multicenter, randomized trial of primary thromboprophylaxis for 2 years after the Fontan procedure.

McCrindle BW, Manlhiot C, Cochrane A, Roberts R, Hughes M, Szechtman B, Weintraub R, Andrew M, Monagle P; Fontan Anticoagulation Study Group.

Source

Labatt Family Heart Centre, Department of Paediatrics, University of Toronto, The Hospital for Sick Children, Toronto, Ontario, Canada. brian.mccrindle@sickkids.ca

Abstract

OBJECTIVES:

The study sought to identify factors associated with increased risk of thrombosis after Fontan.

BACKGROUND:

The Fontan procedure is the culmination of staged palliation for patients with univentricular physiology. Thrombosis is an important complication after this procedure.

METHODS:

An international multicenter randomized controlled trial of acetylsalicylic acid versus warfarin for thromboprophylaxis after the Fontan procedure was conducted in 111 patients, and did not show a significant difference regarding thrombotic complications. We performed a secondary analysis of this previously published manuscript to identify factors associated with thrombosis in this population. Standardized prospective data collection included independent adjudication of all events.

RESULTS:

At 2.5 years after randomization, time-related freedom from thrombosis was 69% (all venous, no arterial events), with 28% of thrombosis presenting with clinical signs or events. Hazard of thrombosis was highest immediately after Fontan with a gradual increase in risk during late follow-up. In multivariable models, factors associated with higher risk of thrombosis were pulmonary atresia with intact ventricular septum (hazard ratio [HR]: 3.64, 95% confidence interval [CI]: 1.04 to 12.70, p = 0.04), pulmonary artery distortion (HR: 2.35, 95% CI: 0.96 to 5.73, p = 0.06), lower pre-operative unconjugated bilirubin (HR: 0.84 μmol/l, 95% CI: 0.72 to 0.99, p = 0.04), use of central venous lines for >10 days or until hospital discharge (HR: 17.8, 95% CI: 3.97 to 79.30, p < 0.001), and lower FiO(2) 24 h after the procedure (HR: 0.67/10%, 95% CI: 0.45 to 1.00, p = 0.06). Patients on warfarin who consistently achieved minimum target international normalized ratio levels or those on acetylsalicylic acid had a decrease in risk of thrombosis compared with patients who often failed to meet target international normalized ratio level (HR: 3.53, 95% CI: 1.35 to 9.20, p = 0.01).

CONCLUSIONS:

More favorable thromboprophylaxis strategies are needed in light of the difficulties in controlling warfarin therapy and the high prevalence of thrombosis in this population.

Comment in

An aspirin a day... [J Am Coll Cardiol. 2013]

Journal Club

Wednesday, November 6, 2013

Post-Fontan thrombotic complications