Healthy liver donors may be at increased risk for blood clots after hepatectomy, Japanese researchers have found.
The retrospective study looked at 55 adult donors, all from the University of Tokyo Hospital, and found that hepatectomy influenced coagulation status, especially in the extrinsic pathway of coagulation.
According to the study, one-third of the healthy liver donors showed a level of prothrombin time-international normalized ratio (PT-INR) of at least 1.5 after hepatectomy. According to guidelines from the American Society of Regional Anesthesia and Pain Medicine, manipulation of an epidural catheter in patients whose PT-INR is more than 1.5 raises their risk for epidural hematoma.
“Coagulation capacity after hepatectomy may be impaired by both reduction in hepatic production of coagulation factors and consumption of extrahepatically stored coagulation factors,” said Yuho Tamai, MD, assistant professor of anesthesiology at the University of Tokyo Hospital, who led the study.
Researchers found that PT-INR did show significant prolongation in hepatectomy patients, which usually does not occur in patients after major abdominal surgeries with equivalent blood loss or operation times. Results of the study also showed that PT-INR increased significantly on postoperative day 1 (1.43±0.13) and continued through day 7, then fell to the preoperative level at discharge. Of the 55 donor patients, 18 showed a PT-INR of at least 1.5 at any postoperative point.
The decreased production capacity of coagulation factors is mostly influenced by the volume of the liver graft. Consumption of coagulation factors stored outside the liver is likely determined by both half-life and distribution of each coagulation factor, Dr. Tamai said.
“I think the best we can do at the present time is to identify donors who may be at a greater risk of having hypercoagulable states,” said David Mulligan, MD, director of the Yale-New Haven Transplantation Center, in New Haven, Conn. “Donors are healthy people. We owe it to them.”
Although safety always is a top concern for donor surgery of living donor liver transplantation (LDLT) with measures like epidural catheter for postoperative analgesia performed on a routine basis, Dr. Tamai said it is important to know as many details as possible about coagulation status to ensure optimal postoperative management.
“It may be better to pay more attention to coagulation status to prevent postoperative hemorrhagic complications including epidural hematoma after hepatectomy,” Dr. Tamai said.
The study investigators reviewed the medical and anesthesia records of 24 male and 31 female patients who underwent donor hepatectomy for adult LDLT from January 2010 through December 2012.
The researchers analyzed several measures of coagulation, including amount of bleeding, blood transfusion volume and liver ischemia time. Baseline characteristics, including age, sex, body weight, amount of bleeding, operating time and graft site also were examined in the donors.
Dr. Mulligan said looking at PT-INR for blood clotting is complicated because minor factors can influence clotting not reflected in the PT-INR. Graft site—left or right lobe—was the only factor found to influence coagulation status in this study.
Dr. Tamai said data on blood coagulation factor concentration at any given point—something that was missing from this study—would be important to know. His group plans to conduct further research in order to know more about which coagulation factor was affected most by hepatectomy.