By Lynda Williams
An imbalance in procoagulant/fibrinolytic blood factors may point to an increased risk for thrombosis following liver surgery, research suggests.
The ratio of von Willebrand factor (vWF) to vWF-cleaving protease rose significantly from a preoperative value of 13-15 to above 20 in the 2 weeks following surgery in three hepatectomy patients who experienced portal vein thrombosis, inferior vena cava thrombosis, and cerebral infarction, respectively.
The enzyme, also known as a disintegrin and metalloprotease with a thrombospondin type 1 motif, member (ADAMTS)13, degrades plasma vWF dimers that are required for thrombosis, explain Masato Nagino (Nagoya University Graduate School of Medicine, Japan) and co-workers.
The team monitored vWF and ADAMTS13 levels in 50 hepatectomy patients undergoing cancer surgery, and 23 pancreatoduodenectomy (PD) patients who underwent surgery between 2010 and 2011.
Autologous blood transfusion was performed in 48% of hepatectomy and 52% of PD patients, and the groups did not significantly differ for other types of transfusion.
vWF levels were significantly higher in the hepatectomy than PD groups at all timepoints including before surgery. In particular, the liver patients experienced a significantly greater increase in vWF immediately after surgery than the PD patients, with a 300-350% peak between 4 and 7 days after surgery.
Mean ADAMTS13 activity was slightly below normal levels in the hepatectomy patients before surgery and fell significantly after the procedure, with a steady decrease for the first 2 weeks.
By contrast, the PD patients experienced a smaller decrease after surgery and ADAMTS13 activity began to recover on postoperative day 1, and had almost completely recovered to baseline levels after 2 weeks.
Finally, the ratio of vWF to ADAMTS13 was significantly higher in hepatectomy patients on day 7 than PD patients, and remained abnormally high until day 14, with peaks noted in three patients who developed thrombosis. Among PD patients, the ratio was stable and "close to normal" over the study period. The ratio also correlated with the size of the remnant liver.
"Our study demonstrated distinct profiles of procoagulant/fibrinolytic factors in patients who underwent a major hepatectomy and patients who underwent a PD," the team writes.
"In addition, we provide evidence that abnormally high vWF to ADAMTS13 ratios in patients who underwent a major hepatectomy may indicate a potential increased risk of thrombotic complications."
They conclude: "Further prospective studies are necessary to examine the importance of vWF to ADAMTS13 ratios and to establish the appropriate therapeutic protocols to normalize vWF to ADAMTS13 ratios and prevent severe thrombotic complications."
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