Bianca Bottasso

Decrease in protein C antigen and formation of an abnormal protein soon after starting oral anticoagulant therapy.

Summary. Changes in protein C antigen (PC: Ag) have been compared with those in factor II, VII, IX and X antigens (II:Ag; VII:Ag; IX:Ag and X: Ag) in 10 patients starting on oral anticoagulant therapy with warfarin, monitored with thrombotest. Between days 0 and 3 of therapy, PC: Ag decreased at the same rate as VII: Ag, whilst IX: Ag, X: Ag and II: Ag decreased at progressively slower rates. On days 15 and 21, clotting proteins and PC: Ag did not differ significantly. Before and after warfarin, PC: Ag had the same mobility on crossed immunoelectrophoresis in Ca2+‐free agarose gel; with Ca2+, a protein with faster anodal mobility appeared on day 1 and became maximal 5 d after warfarin was started. These findings indicate that the rate of PC decrease is closer to that of factor VII than those of factors IX, X and II, and that an abnormal PC with poor Ca2+‐binding properties appears soon after treatment is started. The early decrease in the physiological inactivator (i.e. PC) might contribute to the poor antithrombotic efficacy of anticoagulant therapy during the first days.

Haemostatic and inflammatory biomarkers in advanced chronic heart failure: role of oral anticoagulants and successful heart transplantation

Advanced chronic heart failure (CHF) is associated with abnormal haemostasis and inflammation, but it is not known how these abnormalities are related, whether they are modified by oral anticoagulants (OAT), or if they persist after successful heart transplantation. We studied 25 patients with CHF (New York Heart Association class IV, 10 of whom underwent heart transplantation) and 25 age‐ and sex‐matched healthy controls by measuring their plasma levels of prothrombin fragment 1 + 2 (F1 + 2), thrombin–antithrombin (TAT) complexes, tissue plasminogen activator (t‐PA), plasminogen activator inhibitor‐1 (PAI‐1), D‐dimer, factor VII (FVII), fibrinogen, von Willebrand factor (VWF), tumour necrosis factor (TNF), soluble TNF receptor II (sTNFRII), interleukin 6 (IL‐6), soluble intercellular adhesion molecule‐1 (sICAM‐1), soluble vascular cell adhesion molecule‐1 (sVCAM‐1), endothelial‐selectin (E‐selectin) and thrombomodulin. CHF patients had higher plasma levels of TAT, D‐dimer, t‐PA, fibrinogen, VWF, TNF, IL‐6, sTNFRII, sVCAM‐1 (P = 0·0001), sICAM‐1 (P = 0·003) and thrombomodulin (P = 0·007) than controls. There were significant correlations (r = 0·414–0·595) between coagulation, fibrinolysis, endothelial dysfunction and inflammation parameters, which were lower in those patients treated with OATs. Heart transplantation led to reductions in fibrinogen (P = 0·001), VWF (P = 0·05), D‐dimer (P = 0·05) and IL‐6 levels (P = 0·05), but all the parameters remained significantly higher (P = 0·01–0·0001) than in the controls. Advanced CHF is associated with coagulation activation, endothelial dysfunction and increased proinflammatory cytokine levels. Most of these abnormalities parallel each other, tend to normalize in patients treated with OATs and, although reduced, persist in patients undergoing successful heart transplantation, despite the absence of clinical signs of CHF.

In Vivo Thrombin Generation and Activity During and After Intravenous Infusion of Heparin or Recombinant Hirudin in Patients With Unstable Angina Pectoris

In patients with unstable angina, intravenous heparin reduces thrombin activity but does not influence thrombin generation. Recombinant hirudin, a direct thrombin inhibitor, may be more effective in inhibiting both thrombin generation and activity. We measured the plasma levels of prothrombin fragment 1+2 (a marker of thrombin generation) and fibrinopeptide A (a marker of thrombin activity) in 67 patients with unstable angina enrolled in the GUSTO (Global Use of Strategies to Open Occluded Coronary Arteries) IIb trial who were receiving either recombinant hirudin (31 patients) or heparin (36 patients). Blood samples were obtained at baseline (before any treatment), after 3 to 5 days of study drug infusion (immediately before discontinuation), and 1 month later. In the patients receiving recombinant hirudin, the prothrombin fragment 1+2 levels measured immediately before drug discontinuation were significantly lower than at baseline (P =0.0014), whereas they had not changed in the patients receiving heparin; at this time point, the difference between patients receiving hirudin and those receiving heparin was statistically significant (P =0.032). One month later, the prothrombin fragment 1+2 levels in both groups were similarly persistently high and did not differ from baseline. Fibrinopeptide A plasma levels at the end of infusion were significantly lower than at baseline in both treatment groups (P =0.0005 for hirudin and P =0.042 for heparin) and remained lower after 1 month (P =0.0001 for both hirudin and heparin). The fibrinopeptide A plasma levels were not different between patients treated with hirudin versus heparin at baseline, at the end of infusion, and after 1 month. Thus, in patients with unstable angina, in vivo thrombin generation and activity are reduced during intravenous infusion of recombinant hirudin. However, the inhibition of thrombin generation is not sustained, and after 1 month, the majority of patients have biochemical signs of increased thrombin generation.

l-Arginine therapy in Raynaud's phenomenon?

SummarySincel-Arginine is the substrate for nitric oxide synthesis by vascular endothelial cells the effects ofl-arginine treatment on the digital vascular response to local stimuli were investigated in patients with primary or secondary Raynauds phenomenon. After therapy, patients withu Raynauds phenomenon secondary to systemic sclerosis showed: (1) higher digital vasodilation after local warming, (2) cold-induced digital vasodilation, and (3) increase of plasma levels of tissue-type plasminogen activator.

Hypercoagulability and hyperfibrinolysis in patients with melanoma

The purpose of this study was to evaluate whether or not, using sensitive analytical methods for the measurement of coagulation and fibrinolysis enzyme activity, there was a hypercoagulable state in patients with melanoma, and whether differences existed between those with or without metastases. Seventy-one patients were studied, 45 with localized tumors (stages Ia and Ib) and 26 with metastases (stages II-IV). Plasma level of activated factor VII, prothrombin fragment 1 + 2, thrombin-antithrombin complex, fibrinopeptide A, plasmin-antiplasmin complex and D-dimer were much higher in the whole group of 71 patients than in 45 controls with benign nevi. However, when melanoma patients with or without metastases were compared, there were smaller differences, with only thrombin-antithrombin complex, plasmin-antiplasmin and D-dimer significantly higher in metastatic melanoma. These results indicate that in patients carrying a tumor endowed with high procoagulant activity in vitro, there is a laboratory picture of hypercoagulability with secondary hyperfibrinolysis in vivo. However, differences between patients with localized and metastatic tumors for markers of hypercoagulability are not striking, in spite of the fact that metastatic cells support greater coagulant activity than primary cells in vitro.

Fibrinolytic response in normal subjects to venous occlusion and DDAVP infusion.

A set of fibrinolytic parameters was measured in 40 healthy subjects before and after a venous occlusion (VO) test lasting 10 min. After VO, plasma levels of tissue-type plasminogen activator (t-PA) antigen increased in all subjects, t-PA activity increased only in 25 subjects who were considered responders and remained unchanged in 15 (non-responders). High levels of plasminogen activator inhibitor (PAI) in the non-responder group explain this discrepancy. The non-responders had basal levels of PAI activity and t-PA antigen higher than responders (p less than 0.0001) and their basal levels of t-PA activity were lower (p less than 0.001). DDAVP infusion elicited good responses in 7 of 9 non-responders to VO with a fall of PAI activity to 0. Our data indicate that a high proportion of healthy subjects do not have a fibrinolytic response after VO, that a lack of fibrinolytic response to VO is due to high plasma levels of PAI and that DDAVP infusion appear to be more selective than VO for detecting non-responders.

Effects of subcutaneously administered dermatan sulfate (MF 701) on the coagulation and fibrinolytic parameters of healthy volunteers

Eight healthy volunteers were given single subcutaneous doses of dermatan sulfate (DS, 100, 200 and 400 mg), heparin (5,000 IU) and placebo in random order. Wash-out between treatments was greater than or equal to 10 days. Serial blood samples were taken before and up to 24 hours after treatment to measure coagulation and fibrinolytic parameters. Thrombin generation was significantly inhibited by DS and heparin as compared to placebo. The effect of DS was dose-dependent. Peak inhibition after 200 mg DS was comparable to that of 5,000 IU heparin, but lasted longer. A small, bordeline significant prolongation of APTT was observed after 400 mg DS and heparin. The changes in PAI and fibrinolytic activities were those of the circadian variation. No changes were seen in the other parameters tested. In conclusion, single s.c. doses of DS (200, or 400 mg) inhibit ex vivo thrombin generation equally or more than 5,000 IU heparin and for a longer time. The effect of both treatments on fibrinolysis is negligible.

TREATMENT WITH STANAZOLOL OF TYPE I PROTEIN C DEFICIENCY IN AN ITALIAN FAMILY

SummaryFunctional and immunological assays specific for protein C were employed in the study of a family with congenital protein C deficiency associated with venous thromboembolism. By both assays, four members of the family belonging to two generations had half-normal PC levels. These findings, as well as the normal mobility of the protein in crossed immunoelectrophoresis, suggest that PC deficiency in this family is due to the decreased synthesis of a functionally normal protein. In one member of the family oral administration of the anabolic steroid stanazolol increased PC levels until normal values, suggesting that the defect can be overcome by pharmacological stimulation of protein synthesis.