Value of thrombin-antithrombin III complexes in major orthopedic surgery: relation to the onset of venous thromboembolism

Renal transplant and hemostasis: early postoperative changes in recipients and donors

Background

The benefit of administering pharmacologic thromboprophylaxis following renal transplantation remains uncertain.

Objectives

To compare hemostatic parameters before and after renal transplant surgery in both recipients and their donors at predetermined time points.

Methods

Blood samples were collected at baseline (T1), immediately after surgery (T2), and at 24 hours after surgery (T3) in both recipients and donors and at 72 (T4) and 120 hours (T5) from recipients only. Assays included in vitro thrombin generation, factor VIII (FVIIIc) activity, von Willebrand factor (VWF) antigen, D-dimer, antithrombin activity, prothrombin fragment 1 + 2 (F1 + 2), thrombin-antithrombin complexes, and plasminogen activator inhibitor-1 (PAI-1) antigen.

Results

Fifty-two patients (28 recipients and 24 donors) were enrolled. Both donors and recipients had increased FVIIIc, VWF, F1 + 2, D-dimer, and PAI immediately after surgery but reduced antithrombin. Mixed-model analysis showed that the magnitude of change over time (between T1 and T3) for FVIIIc (mean estimated difference [MED], 72; 95% CI, 41-102; P < .0001), VWF (MED, 89; 95% CI, 35-142; P = .001), F1 + 2 (MED, 283; 95% CI, 144-422; P < .0001), thrombin-antithrombin complexes (MED, 3.5; 95% CI, 1.9-5.1; P < .0001), D-dimer (MED, 2.2; 95% CI, 1.0-3.3; P < .0001), PAI-1 (MED, 9.2; 95% CI, 3.4-14.9; P = .002), and time to peak thrombin generation (MED, 1.5; 95% CI, 0.35-2.7; P = .01) was more significant in recipients than in donors.

Conclusion

Persistence of a hypercoagulable state was more prominent in recipients after 24 hours despite recovery in renal function and initiation of thromboprophylaxis.

Enteral immuno-enhanced diets with arginine are safe and beneficial for patients early after esophageal cancer surgery

We previously reported that provision of immediate enteral nutrition (EN) with a certain amount of omega (omega)-3 fatty acids (FAs) in patients after esophageal cancer surgery resulted in reduced platelet aggregation, coagulation activity, and cytokine production. We investigated whether EN using immuno-enhanced diet (IED) containing a large amount of omega-3 FAs as well as arginine and RNA affected the above-described responses. We also attempted to reveal whether arginine in the IED can potentially harm patients who undergo esophageal cancer surgery. Twenty-nine patients with esophageal cancer who underwent similar surgical procedures were selected. All patients received EN starting immediately after surgery. Fourteen patients received the formula with fewer omega-3 FAs, and fifteen patients received the IED. Administration of the IED tended to inhibit postoperative decrease in platelet count. Prothrombin activity and thrombin-antithrombin III complex levels were significantly reduced in the IED group. Plasma IL-8 levels were significantly lower (P < 0.05) in patients without the IED on the fifth postoperative day (POD). The proportion of T-cells was significantly higher (P < 0.05) in the IED group on PODs 1 and 7. Nitrate/nitrite levels did not differ significantly between the two groups. Early EN with an IED may enhance the inhibitory effects on postoperative platelet aggregation and hypercoagulation, and appeared to be advantageous to T-cell proliferation. These effects are expected to be beneficial in patients at risk of developing infectious complications. This study also showed that the IED could be safely used without any adverse effects for patients early after a radical surgery for the esophageal cancer.

Production of tissue factor by pancreatic islet cells as a trigger of detrimental thrombotic reactions in clinical islet transplantation

BACKGROUND

Intraportal transplantation of pancreatic islets offers improved glycaemic control and insulin independence in type 1 diabetes mellitus, but intraportal thrombosis remains a possible complication. The thrombotic reaction may explain why graft loss occurs and islets from more than one donor are needed, since contact between human islets and ABO-compatible blood in vitro triggers a thrombotic reaction that damages the islets. We investigated the possible mechanism and treatment of such thrombotic reactions.

METHODS

Coagulation activation and islet damage were monitored in four patients undergoing clinical islet transplantation according to a modified Edmonton protocol. Expression of tissue factor (TF) in the islet preparations was investigated by immunohistochemistry, immunoprecipitation, electron microscopy, and RT-PCR. To assess TF activity in purified islets, human islets were mixed with non-anticoagulated ABO-compatible blood in tubing loops coated with heparin.

FINDINGS

Coagulation activation and subsequent release of insulin were found consistently after clinical islet transplantation, even in the absence of signs of intraportal thrombosis. The endocrine, but not the exocrine, cells of the pancreas were found to synthesise and secrete active TF. The clotting reaction triggered by pancreatic islets in vitro could be abrogated by blocking the active site of TF with specific antibodies or site-inactivated factor VIIa, a candidate drug for inhibition of TF activity in vivo.

INTERPRETATION

Blockade of TF represents a new therapeutic approach that might increase the success of islet transplantation in patients with type 1 diabetes, in terms of both the risk of intraportal thrombosis and the need for islets from more than one donor.