Incidence, outcome and risk stratification tools for venous thromboembolism in advanced pancreatic cancer - A retrospective cohort study.

INTRODUCTION: Venous thromboembolism (VTE) is frequent in advanced pancreatic cancer (APC). Recent studies demonstrated that the Khorana score - an established risk stratification tool for VTE in cancer - performs poorly in identifying pancreatic cancer patients at high risk for VTE. MATERIALS AND METHODS: We performed a retrospective cohort study in order to define incidence, treatment and outcome of VTE as well as the performance of VTE risk stratification tools (Khorana score, CONKO score and aPTT ratio) in a "real life" clinical cohort of APC patients undergoing palliative chemotherapy. RESULTS AND CONCLUSIONS: One hundred and seventy-two eligible APC patients from our comprehensive cancer center were identified. VTE after start of palliative chemotherapy was diagnosed in 71 patients (41.3%). Most VTE events were asymptomatic (n=50, 29.1%) with only 21 symptomatic events (12.2%). On multivariate analysis - including age, performance status and carbohydrate antigen 19-9 (CA 19-9) - symptomatic VTE was an independent risk factor for death (hazard ratio [HR]: 2.22, 95% CI: 1.05-2.60, p<0.05). Khorana score, CONKO score and aPTT ratio alone were not able to predict the risk for symptomatic VTE. High risk patients could only be identified by using a combination of either Khorana or CONKO score with aPTT ratio (30% vs. 10% symptomatic VTE events in high vs. low risk patients, p<0.05). The combination of Khorana or CONKO score with aPTT thus may represent a novel risk stratification tool for symptomatic VTE in APC and should further be validated within prospective clinical trials.

Antithrombin is as effective as heparin and hirudin to prevent formation of microvascular thrombosis in a murine model.

A recently published post-hoc analysis of a trial using high-dose antithrombin (AT) in septic patients (KyberSept) revealed significant reduction of lethality when no concomitant heparin was administered, whereas patients with the combination of heparin and AT did not benefit in terms of survival. Therefore, it seems feasible to study the capability of AT in prevention of microvascular thrombus formation to avoid concomitant application of heparin and AT. Using fluorescence microscopy and a light/dye-injury mouse ear model, the kinetics of thrombus formation were analyzed quantitatively in vivo upon single iv bolus of saline (control), heparin (100 IU/kg), hirudin (1 mg/kg) or AT (25, 50, 100 or 250 IU/kg) (N = 7 animals per group each). In controls, light/dye-injury induced complete thrombotic occlusion in all arterioles and venules studied. Heparin and hirudin prevented thrombotic vessel occlusion in 62% and 43% of arterioles and 11% and 28% of venules. AT-250 was found to be more effective than heparin and hirudin, because thrombus formation was completely banned in all arterioles and venules. AT-100 and AT-50 were also capable of significantly blocking thrombus formation in both arterioles and venules. In blood vessels, which finally clogged, the time for development of complete vessel occlusion was delayed after heparin, hirudin and AT-25, but in particular after AT-50 and AT-100. In conclusion, AT-mediated antithrombotic activity has been characterized in a model of phototoxicity-induced microvascular thrombosis formation, demonstrating that AT delays and prevents thrombus formation in arterioles and venules at least comparably effective as heparin and hirudin.

Diagnosis of hepatic veno-occlusive disease by plasminogen activator inhibitor-1 plasma antigen levels: a prospective analysis in 350 allogeneic hematopoietic stem cell recipients.

BACKGROUND: Veno-occlusive disease (VOD) is one of the most serious complications following allogeneic hematopoietic stem cell transplantation (HSCT) and is associated with a high mortality. We conducted a large trial in order to investigate the value of plasminogen activator inhibitor-1 (PAI-1) plasma antigen levels in VOD patients as PAI-1 has been described as a possible diagnostic marker of VOD. METHODS: In all, 350 stem cell recipients were included in our study. PAI-1 levels were analyzed prior to conditioning therapy and then weekly until eight weeks after HSCT. Transplantation-related complications (TRC) including VOD, microangiopathic hemolytic anemia (MAHA), and graft-versus-host disease (GVHD) were recorded weekly throughout the study. RESULTS: Maximum PAI-1 antigen levels were increased in all patients with VOD (n=15; mean 248 ng/ml; 95% CI 183-314 ng/ml). Maximum PAI-1 levels above 120 ng/ml showed a sensitivity of 100% and a specificity of 30.6% for VOD after HSCT. CONCLUSION: Our study underlines that maximum PAI-1 plasma antigen levels not exceeding 120 ng/ml have a strong negative predictive value in the diagnosis of VOD and thus represent a helpful non-invasive tool for exclusion of VOD after HSCT.

Platelet activation markers in patients with heart assist device.

Clinical use of heart assist devices is often associated with thromboembolic complications. We hypothesized that platelets may be activated in patients receiving assist devices and examined expression of the platelet activation markers CD62, CD63, and thrombospondin using flow cytometry in eight patients with Novacor left ventricular assist system (LVAS) or Berlin Heart. Patients with end-stage heart failure had elevated expression of platelet activation markers before insertion of the assist device. While CD62 (P < 0.05) and thrombospondin expression (n.s.) decreased by the 14th postoperative day, the CD63 expression remained elevated (n.s.). A good correlation was found between CD62 and thrombospondin expression (r = 0.72). Bleeding time ex vivo indicated platelet dysfunction during the first 4 weeks after implantation. No relation between expression of platelet activation markers and bleeding time ex vivo were found. In conclusion, expression of the platelet activation markers CD62, CD63, and thrombospondin is increased in patients with end-stage heart failure before device placement and shows prolonged elevation during the assist period. Future studies in larger patient populations are necessary to identify new and specific markers of platelet activation in this clinical setting.