Role of blood transfusion product type and amount in deep vein thrombosis after cardiac surgery

•Duplex venous scans (DVS) confirmed postoperative DVT in 13% of cardiac surgery patients despite maximal thromboprophylaxis.•Post cardiac surgery DVTs were predominantly diagnosed during hospitalization and were clinically silent or asymptomatic.•Adjusting for post-op morbidity and lack of ambulation, RBC transfusion increased DVT risk in a dose-dependent fashion.•The RBC Transfusion - DVT association is exacerbated when the RBC transfusion is also accompanied with FFP.•Postoperative screening DVS, in transfused high risk for DVT patients, are warranted and will facilitate timely intervention.

BackgroundPostoperative deep vein thrombosis (DVT) is associated with significant morbidity. Even with maximal thromboprophylaxis, postoperative DVT is present in 10% of cardiac surgery patients, and is linked to receiving transfusion. We hypothesized that the incidence of DVT varies with the transfused blood product type, and increases with transfusion dose.Study design and methods139/1070 cardiac surgery patients have DVT despite maximal chemo and mechanical prophylaxis. DVTs were detected via serial perioperative duplex venous scans (DVS). Red blood cells (RBC), platelets (PLT), plasma (FFP) and cryoprecipitate transfusion data were collected.ResultsTransfusion was used in 506(47%) patients: RBC [468(44%); 4.0 ± 4.2 u]; FFP [155(14.5%); 3.5 ± 2.3 u]; PLT [185(17.3%); 2.2 ± 1.3 u] and Cryoprecipitate [51(4.8%); 1.3 ± 0.6 u]. Isolated RBC transfusion accounted for 92.6% patients receiving one product, and their DVT rate was increased considerably compared to no transfusion (16.7% versus 7.3%; P < 0.001). Incidence of DVT increased substantially for multiple product transfusions; particularly when both RBC and FFP are used (25%-40%).Relative to no RBC (n = 602), multivariate logistic regression analysis identified a significant RBC-DVT dose dependent relation (P < 0.001) with: 1-3 RBC units [n = 285, AOR = 1.95(1.23-3.07), adjusted odds ratio (95% confidence interval)]; 4-6 units [n = 117; AOR = 1.65(0.86-3.20)]; and ≥ 7 RBC units [n = 66; 3.19(1.52-6.70)]. This relation also increased according to an RBC ∗ FFP interaction term [AOR = 1.87(1.11-3.22); P = 0.022].ConclusionRBC transfusion is associated with increased risk of DVT after cardiac surgery in a dose-dependent fashion that is exacerbated when accompanied with FFP. Postoperative screening diagnostic DVS are warranted in this transfused, high risk for DVT population to facilitate timely therapeutic intervention.