The spectrum of von Willebrand's disease revisited

We have examined nine patients with presumed von Willebrand's disease who present the spectrum of that disorder. Two had findings that would be accepted generally as diagnostic of von Willebrand's disease, and seven had variations of the usual pattern. The commonest variation was the combination of borderline and variable levels of coagulant Factor VIII, commensurate levels of Factor VIII-related antigen, and low levels of ristocetin-Willebrand factor.

Treatment of life-threatening hemorrhage due to acquired factor VIII inhibitor

An otherwise healthy elderly man developed massive, life-threatening, sublingual bleeding associated with an idiopathic factor VIII inhibitor. The patient was treated wtih cyclophosphamide, steroids, factor VIII concentrates, and repeated plasmapheresis (including three times with NCI-IBM blood-cell separator). Rapid clinical and laboratory improvement occurred, with complete disappearance of the inhibitor. The patient has remained well, without evidence of an inhibitor, for 8 mo. The possible role of each of the therapeutic measures in the disappearance of the inhibitor and the possible pathogenetic mechanism of this disorder are discussed. A high mortality rate and a striking incidence of sublingual hematoma have been observed in cases in the literature.

Liver transplantation in pigs with von Willebrand's disease

Nine pigs with von Willebrand's disease (vWd pigs) received normal auxiliary livers; in the immediate postoperative period, three pigs died, three survived from 3 days to 3 weeks, and three were killed 5-13 weeks postoperatively. There was an increase in factor VIII (up to 90 u/dl) but with a type of factor VIII that was more labile than normal and that decreased after 2 weeks, probably as a result of liver rejection. There was a slight increase in the levels of the ristocetin-Willebrand factor postoperatively (up to 11%) but this activity was undetectable after 2 weeks. There was no correction of the abnormal bleeding time and platelet retention. When a vWd liver was transplanted orthotopically into a normal pig, the factor-VIII coagulant activity and the ristocetin-Willebrand factor remained normal. The abnormality in porcine von Willebrand's disease is only partially corrected by liver transplantation, which suggests that there also is extrahepatic synthesis of the missing or abnormal plasmatic activity or activities.

Effect of heparin on chronically induced intravascular coagulation in dogs

When intermediate-strength thromboplastin was continuously infused into dogs for 10 days or more, platelet counts decreased sharply and factor VIII concentrations decreased by more than 50%. There was little change in plasma fibrinogen, prothrombin, factor V, antithrombin III, plasminogen, prothrombin time, and thrombin time values. When heparin was infused (25-50 U/kg per h) along with the same thromboplastin, there was no change in onset or degree of thrombocytopenia. However, the decrease in factor VIII was abolished and there were significant increases in fibrinogen, prothrombin, and factor V. The absolute concentrations of the various clotting factors seemed to give no indication of their turnover rates. Unexplained is the remarkable heparin tolerance that developed in these dogs.

Ultrastructure of platelets in Bernard-Soulier syndrome

The platelets of a patient with the Bernard-Soulier syndrome were studied by electron microscopy. The main abnormalities were the presence of giant and often round platelets, hypertrophic and frequently widely dilated open canalicular system, disorganized microtubules, and platelets with sparse or absent granulation. Although well defined, these ultrastructural morphologic aberrations are not considered diagnostic or pathognomonic of the syndrome.

Evaluation of ristocetin-Willebrand factor assay and ristocetin-induced platelet aggregation

Normal subjects, patients with various bleeding disorders, and patients with von Willebrand's disease were studied. All patients with von Willebrand's disease had decreased levels of ristocetin-Willebrand factor (range, 0 to 41%) as compared with all other subjects (range, 79 to 202%). Ristocetin-induced platelet aggregation of platelet-rich plasma was abnormal in all patients with von Willebrand's disease tested, and it was possible to correct this abnormal response by addition of normal platelet-poor plasma. Abnormal ristocetin-induced platelet aggregation was seen in patients with intrinsic platelet disorders or, on some occasions, in normal patients who had ingested aspirin. Ristocetin-induced platelet aggregation is not diagnostic, but it may be useful as a simple screening test for patients with possible von Willebrand's disease. In conjunction with other tests, the assay for ristocetin-Willebrand factor will be useful in diagnosis and evaluation of these patients.

Effect of induced chronic intravascular coagulation on plasminogen activator in dogs

Plasminogen activator activity in blood vessels of various organs was determined in three untreated (control) male dogs and in two male dogs that received a continous infusion of canine brain thromboplastic emulsion for 2 weeks. Activator was measured by the speed and degree of lysis of fibrin films that were overlaid with slices of tissue. Depletion of vascular plasminogen activator occurred in the vena cava of treated dogs at the site of the tip of the catheter, which was surrounded by a clot. A decrease of activator was found in most organs and particularly in certain endocrine organs (thyroid, pituitary, and testis). Of organs that normally contained the most activator, the greatest depletion was found in the skin, lung, and penis. The wide variation of plasminogen activator activity in organs of normal dogs is described.