Fibrinolysis during major abdominal surgery

Influence of the sampling technique on the measurement of peritoneal fibrinolytic activity

OBJECTIVE

To establish the influence of the peritoneal sampling technique on the measurement of fibrinolytic capacity.

DESIGN

Clinical study.

SETTING

University hospital, Germany.

SUBJECTS

40 peritoneal biopsy specimens were taken from 10 patients who were having elective colorectal resections.

INTERVENTIONS

Peritoneal biopsy specimens were taken either with a biopsy punch (n = 20) or manually with forceps and scissors (n = 20).

MAIN OUTCOME MEASURES

Extent of agreement in fibrinolytic activities between specimens taken with biopsy punch and manually. Major endpoint-peritoneal tissue plasminogen activator (t-PA) activity. Minor endpoints-peritoneal tissue plasminogen activator concentration, and concentration and activity of plasminogen activator inhibitior type 1 (PAT-1).

RESULTS

Intra-assay agreement and the extent of agreement between the groups were evaluated by the method of Bland and Altman. Correlation of repeated measurements of t-PA and PAI-1 concentrations and activities from the same sample using the same ELISA kit was high (r = 0.93-0.99, p < 0.01). t-PA activities and concentrations between the groups correlated poorly (r= 0.60 and 0.66, p < 0.01) while no correlation at all was seen for PAI-1 concentration and activity between the groups (r = 0.6 and 0.1, p = 0.2 and 0.9). The mean differences between the groups ranged from -27% to -4.8%.

CONCLUSION

The sampling technique considerably affects the measurement of peritoneal fibrinolytic activity.

Coagulation and fibrinolysis during laparoscopic cholecystectomy

Laparoscopic surgery appears to be less traumatic to the patient than open surgery, but its influence upon coagulation and fibrinolysis is incompletely elucidated. Our aim was to measure markers of coagulation and fibrinolysis before, during. and after laparoscopic cholecystectomy (LC). Blood samples drawn on admission, on four occasions during operation as well as 2 hours after operation and on the first postoperative day in 50 patients undergoing elective LC were analyzed for prothrombin fragment 1+2 (F1+2), soluble fibrin (SF), D-dimer (DD), fibrin degradation products (FbDP), tissue-type plasminogen activator (tPA) activity and antigen, and plasminogen activator inhibitor (PAI) activity and antigen. F1+2, SF, DD, and FbDP levels increased significantly after LC. Differences between pre- and postoperative PAI and tPA levels were not significant apart from a transient increase in tPA antigen levels. tPA activity was significantly increased during operation.

Fibrinolytic activity in laparoscopic cholecystectomy

The aim of this study was to examine the fibrinolytic activity in laparoscopic cholecystectomy (LC) to determine whether changes occur that might indicate a greater risk of thrombosis. The study was carried out in 20 patients who had undergone laparoscopic surgery for cholelithiasis without complications. The average age was 59.4 years (34-77 years). Seventy-five percent were women. The mean operating time was 70 minutes (35-120 minutes). Pneumoperitoneum at 14 mm Hg was maintained in all patients, and they were in 30 degrees reverse Trendelenburg position. Postoperative mobilization was obtained before 24 hours, and patients were discharged 48 hours after surgery. The control group was composed of 12 patients, evenly distributed by age, sex, and length of surgery, who had undergone Bassini herniorrhaphy without complications or relapses. The following hemostatic parameters were studied: plasma fibrinolytic activity (PFA), euglobulin fibrinolytic activity (EFA), tissue-type plasminogen activator (t-PA), fast-acting plasminogen activator inhibitor-1 (PAI-1), and D-dimer (D-D). Samples were obtained at the following times: (1) under basal conditions the day before surgery, (2) preoperatively, (3) at the end of surgery, (4) 24 hours after surgery, and (5) on the seventh day following surgery. No patient had clinical manifestations of thromboembolic disease immediately after surgery or during an average follow-up period of 16 months (range 15-18 months). Analysis of the results of global fibrinolysis showed that fibrinolytic activity was enhanced only in the postoperative period (third sample) of the LC patients. The fraction of euglobulins enhances fibrinolytic activity in both groups in the third sample with regard to the other determinations; the LC patients showed a higher degree of significance (p<0.005). A significant increase of postoperative t-PA in both groups was found, being more significant in the LC group (p<0.005). In the PAI-1 values, no significant differences existed between either determinations or groups. A significant increase in D-dimer (p<0.05) occurred in the immediate postoperative period (third sample) and 24 hours later (fourth sample), returning to normal basal values on the seventh day. No significant differences were found between the two groups. These results seem to indicate that LC produces an increase in the fibrinolytic activity in plasma as a result of the liberation of tissue plasminogen activator from the venous endothelium, which could indicate hypocoagulability during the immediate postoperative period and, therefore, signify less thrombotic risk for patients undergoing this procedure.

Depression of peritoneal fibrinolysis during operation is a local response to trauma

BACKGROUND

Peritoneal fibrinolytic capacity decreases during abdominal operation. This may be a local effect or a part of a generalized response to the procedure.

METHODS

Plasma and paired peritoneal biopsy specimens were taken at intervals during abdominal operation, and fibrinolytic components were assayed in plasma and tissue extracts. Values are given as median [interquartile range].

RESULTS

In peritoneal tissue there was a gradual decrease of tissue-type plasminogen activator (tPA) activity, and at 90 minutes of the operation differed significantly from that of the initial sample (1.0 [1.0] ng/mg protein, and 5.1 [6.5] ng/mg protein, respectively, p < 0.05). The tPA activity levels at the wound were significantly lower (1.0 [1.0] ng/mg protein) at 90 minutes compared with a remote peritoneal site (1.8 [1.9] ng/mg protein, p < 0.05). At the wound, the tPA activity correlated significantly with time (r = -0.48, n = 26, p < 0.01). tPA activity and antigen peaked in plasma at 30 minutes (p < 0.05) and 60 minutes (p < 0.05), respectively. Plasminogen activator inhibitor type 1 activity increased in plasma during operation (p < 0.05), but was not detectable in peritoneal samples.

CONCLUSIONS

The intraoperative changes in tissue tPA activity were not consistently reflected in plasma samples. These findings suggest that the reduction in peritoneal fibrinolysis during abdominal operation is a local response to trauma.

Plasminogen activators and plasminogen activator inhibitor in portal blood from patients with and without gastric malignancy

BACKGROUND

Plasminogen activators (PA) may be released by the gut and eliminated by the liver. Patients with liver disorders or malignancy often have abnormal plasma levels of PAs. Some tumours may produce PAs.

METHODS

In patients undergoing gastric surgery for malignant (n = 18) or benign (n = 21) disorders., blood drawn from the portal vein and a peripheral vein was analysed for tissue-type plasminogen activator antigen and activity (tPA: Ag, tPA: Act), single-chain urokinase-type plasminogen activator activity (scuPA: Act), and plasminogen activator inhibitor antigen and activity (PAI: Ag, PAI: Act).

RESULTS AND CONCLUSIONS

In both groups tPA: Act and scuPA: Act levels were significantly higher in portal blood than in peripheral blood, but tPA: Ag and PAI: Act levels did not differ. PAI: Act levels were significantly lower in patients with malignant disease, but levels of the other markers did not differ in the two groups.

The effects of gynaecological surgery on coagulation activation, fibrinolysis and fibrinolytic inhibitor in patients with and without ketorolac infusion

The effects of gynaecological surgery on the fibrinolytic and inhibitor mechanisms were followed up for 24 h post-operatively in patients receiving a single dose of ketorolac infusion (n = 18) as compared with those not receiving ketorolac infusion (n = 11). A pre-operative state of lower mean t-PA activity and higher PAI-1 levels with increased platelet activation than that reported in normal subjects were observed in both groups of patients. Increased t-PA activity upon anaesthetic induction together with a decreased level at 24 h post-operation was seen in both groups. However, fibrinolytic 'shut-down' was not evident as significant increase in D-dimer levels was observed post-operatively, suggesting an enhanced lytic state concurrent with an enhanced activation of coagulation and diminished platelet activation although beta-TG remained above the normal level; plasmin from this enhanced lytic state affects platelet adhesion and cleaves platelet glycoprotein Ib thus inhibit release reaction. Ketorolac infusion elicited a significant response in PAI-1 activity within 24 h post-operation and this was not seen in the non-ketorolac group in spite of the rising trend by 24 h post-operation which did not achieve statistical significance. There were no statistical significant differences in blood loss and duration of surgery between the two groups of patients. Overall, both groups of patients showed similar haemostatic changes post-operatively for 24 h, a longer duration of post-operative study would have revealed any subtle changes in the molecular markers of thrombosis which was not the objective of this study.

Increased tissue-type plasminogen activator activity in orthotopic but not heterotopic liver transplantation: the role of the anhepatic period

The major cause of the increased tissue-type plasminogen activator activity during orthotopic liver transplantation is still unclear. Both the lack of hepatic clearance of tissue-type plasminogen activator in the anhepatic period and increased endothelial release from the graft on reperfusion have been proposed as the major causes. Heterotopic liver transplantation avoids the resection of the host liver and is a useful model to help differentiate between these two possibilities. In this study the fibrinolytic system was evaluated in 10 orthotopic liver transplantations, 18 heterotopic liver transplantations and a control group of 10 partial hepatic resections. A marked increment in tissue-type plasminogen activator activity, from 0.2 to 5.2 IU/ml (p less than 0.02), was observed during the anhepatic period of orthotopic liver transplantation, which rapidly normalized after reperfusion. In contrast, tissue-type plasminogen activator activity levels remained normal in heterotopic liver transplantation and partial hepatic resections. In orthotopic liver transplantation and in heterotopic liver transplantation no increase occurred in tissue-type plasminogen activator activity after reperfusion. The first venous hepatic outflow after reperfusion did not contain elevated tissue-type plasminogen activator activity levels. Plasma degradation products of fibrin and fibrinogen increased during the anhepatic period of orthotopic liver transplantation (from 2.60 to 8.80 micrograms/ml [p less than 0.008] and from 0.40 to 1.60 micrograms/ml [p less than 0.04], respectively) and remained elevated thereafter. In heterotopic liver transplantation and partial hepatic resections these levels remained low. In conclusion, the lack of hepatic clearance during the anhepatic period is probably the most important factor in the evolution of increased tissue-type plasminogen activator activity during orthotopic liver transplantation.

Pharmacokinetics of low-molecular-weight heparin and unfractionated heparin during elective aortobifemoral bypass grafting

Perioperative monitoring has demonstrated that administration of heparin on an empirical basis is associated with a wide variation in patient response and elimination rate. This problem may be overcome by intervention on the basis of perioperative monitoring or by using forms of heparin with different pharmacokinetic properties. When compared with unfractionated heparin, low-molecular-weight heparin has a higher bioavailability after subcutaneous administration, a linear clearance mechanism with a prolonged half-life, and is at least as effective in preventing postoperative vein thrombosis. Theoretically these characteristics of low-molecular-weight heparin could lead to more predictable levels of heparin activity. In this study we compared the pharmacokinetics of low-molecular-weight heparin and unfractionated heparin after an intravenous injection in patients undergoing aortic graft surgery. Heparin activity was measured before heparin administration and at 5, 20, 35, 50, 65, 80, 95, and 110 minutes after administration. The anti-Xa activity in the low-molecular-weight heparin group showed less variation and was more sustained when compared to the unfractionated heparin group. Fibrin degradation products were moderately correlated with the anti-factor Xa levels of the low-molecular-weight heparin group, but no correlation was found in the unfractionated heparin group. The anti-factor Xa activity of low-molecular-weight heparin was, in contrast to that of unfractionated heparin, not completely reversible by protamine administration. The blood loss was comparable in both groups. In contrast to what was expected, the pharmacokinetic profiles of low-molecular-weight heparin and unfractionated heparin showed a similarity after intravenous injection in patients undergoing aortobifemoral bypass grafting. Factors that could have influenced the pharmacokinetic behavior of heparin are discussed.