The Role of Intrinsic Fibrinolytic System Activation in Pathogenesis of Hemostasis Disturbances in Hemodialized Patients with Chronic Renal Failure

Perioperative hyperfibrinolysis - physiology and pathophysiology

Introduction and objectives

The role of the anesthesiologist in the perioperative management of hemostasis has attracted increasing attention. The fibrinolytic system participates in hemostasis, removing clots after repair of the vascular injury. Over the past two decades, several studies have assessed the efficacy and safety of antifibrinolytic agents in reducing perioperative bleeding and transfusion requirements. Some of the conditions that seem to benefit from antifibrinolytic drugs involve trauma, postpartum hemorrhage, cardiac surgery, spine surgery, knee or hip arthroplasty, urological and gynecological surgery, among others. However, there are currently few publications focusing on the perioperative features of fibrinolytic system, which will be the subject of the present review.

Content and conclusions

Fibrinolytic physiology, its relationship with the clot structure and its perioperative behavior are described. Pathophysiological mechanisms related to anesthesiology clinical practice and their possible perioperative scenarios are addressed according to a suggested classification. This article aims to provide anesthesiologists with a broader understanding of the normal functioning of fibrinolysis, the mechanisms of possible deviations from normality in the perioperative period, the pathophysiological rationale supporting the current indications of antifibrinolytics, and some recent outcomes obtained with their use.

Coagulation and Fibrinolysis in Kidney Graft Rejection

Coagulation system is currently considered an integrated part of innate immunity. Clotting activation in response to bacterial surface along with complement cascade priming represents the first line of defense against pathogens. In the last three decades, we learned that several coagulation factors, including factor II or thrombin and factor X, can interact with specific cell surface receptors activated by an unusual proteolytic mechanism and belonging to a novel class of G-protein-coupled receptors known as protease-activated receptors (PARs). PARs are expressed by a variety of cells, including monocytes, dendritic cells, and endothelial cells and may play a key role in the modulation of innate immunity and in the regulation of its interaction with the adaptive branch of the immune system. Also, the fibrinolytic system, in which activation is controlled by coagulation, can interact with innate immunity, and it is a key modulator of extracellular matrix deposition eventually leading to scarring and fibrosis. In the setting of kidney transplantation, coagulation and fibrinolytic systems have been shown to play key roles in the ischemia/reperfusion injury featuring delayed graft function and in the pathogenesis of tissue damage following acute and chronic rejection. In the present review, we aim to describe the mechanisms leading to coagulation and fibrinolysis activation in this setting and their interaction with the priming of the innate immune response and their role in kidney graft rejection.

Percutaneous instillation of physiological saline solution for the treatment of femoral pseudoaneuryms

OBJECTIVE

To investigate the efficacy of para-aneurysmal saline injection for closure of postcatheterization pseudo-aneurysm (PA) at the vascular access site.

METHODS

Fifty-one consecutive patients with postcatheterization PA at the vascular access site were included to undergo percutaneous para-aneurysmal saline injection. In case of technical failure the day after, PA were treated by bovine thrombin injection. Anatomical properties of the PA were recorded as were details to injection.

RESULTS

Initially all patients exhibited success which was reduced to 43 % at day one. A saline volume of median 7 ml (interquartile range 6-8 ml) has been injected. The amount of injected saline was not different in patients with and without treatment success at day one (P = 0.6). Several anatomical properties of the PA exhibited marked differences in patients with or without success. The length (10.3 mm (7.8-12.0) vs. 12.5 mm (10.3-15.0); P = 0.009) and the angulation (110° (100-118) vs. 140° (129-146); P < 0.001) of the fistula/vessel axis was statistically different between groups. The peak systolic velocity failed to show significance with a tendency to higher values in the ineffective study group (P = 0.07). No peripheral complications occurred.

CONCLUSION

Para-aneurysmal saline injection may be a therapeutic alternative to percutaneous thrombin injection in patients exhibiting favorable anatomical properties.

Role of orosomucoid in the regulation of plasma proteolytic systems during experimental renal failure

Activity of plasma proteolytic systems was studied in outbred albino rats with acute renal failure. The possibility of treating this disorder with acute phase protein alpha-1-acid glycoprotein was evaluated. Acute renal failure was induced by single subcutaneous injection of mercury chloride (II). The parameters were evaluated on day 5 postinjection. alpha-1-Acid glycoprotein in a dose of 150 mg/kg was administered 3 times. Acute renal failure was accompanied by activation of the complement system and fibrin formation (with factors for the intrinsic and common pathways of blood coagulation) and inhibition of the fibrinolytic system and antithrombin activity. Treatment with glycoprotein was followed by partial recovery of fibrin formation and complement system. These changes were probably related to accumulation of glycoprotein in the renal tissue and in situ protective effect.