Clinically relevant differences between assays for von Willebrand factor activity.

Essentials It is unclear whether there are differences between von Willebrand factor (VWF) activity assays. We compared the four most used VWF activity assays in 661 von Willebrand disease (VWD) patients. All assays correlated excellently, but a discrepant classification was seen in 20% of patients. Differences between VWF activity assays have a large impact on the classification of VWD. SUMMARY: Background Measuring the ability of von Willebrand factor (VWF) to bind to platelets is crucial for the diagnosis and classification of von Willebrand disease (VWD). Several assays that measure this VWF activity using different principles are available, but the clinical relevance of different assay principles is unclear. Objective To compare the four most widely used VWF activity assays in a large VWD patient population. Methods We measured VWF:RCo (ristocetin to activate VWF + whole platelets), VWF:GPIbR (ristocetin + platelet glycoprotein Ib receptor [GPIb] fragments), VWF:GPIbM (gain-of-function GPIb fragments that bind VWF spontaneously without ristocetin) and VWF:Ab (monoclonal antibody directed against the GPIb binding epitope of VWF to mimic platelets) in 661 VWD patients from the nationwide 'Willebrand in the Netherlands' (WiN) Study. Results All assays correlated excellently (Pearson r > 0.9), but discrepant results led to a different classification for up to one-fifth of VWD patients. VWF:RCo was not sensitive enough to classify 18% of patients and misclassified half of genotypic 2B VWD patients, especially those with p.Arg1306Trp. VWF:GPIbR was more sensitive, accurately classified the vast majority of patients, and was unaffected by the p.Asp1472His variant that causes artificially low VWF:RCo. VWF:GPIbM was the most precise assay but misclassified over a quarter of genotypic 2A, 2B and 3 patients. VWF:Ab, often not considered an actual VWF activity assay, performed at least equally to the other assays with regard to accurate VWD classification. Conclusion Although the different VWF activity assays are often considered similar, differences between assays have a large impact on the classification of VWD.

Analysis of current perioperative management with Haemate® P/Humate P® in von Willebrand disease: Identifying the need for personalized treatment.

INTRODUCTION: Patients with Von Willebrand disease (VWD) are regularly treated with VWF-containing concentrates in case of acute bleeding, trauma and dental or surgical procedures. AIM: In this multicentre retrospective study, current perioperative management with a von Willebrand factor (VWF)/Factor VIII (FVIII) concentrate (Haemate® P) in patients with VWD was evaluated. PATIENTS/METHODS: Patients with VWD undergoing minor or major surgery between 2000 and 2015, requiring treatment with a VWF/FVIII concentrate (Haemate® P), were included. Achieved VWF activity (VWF:Act) and FVIII during FVIII-based treatment regimens were compared to predefined target levels in national guidelines. RESULTS: In total, 103 patients with VWD (148 surgeries) were included: 54 type 1 (73 surgeries), 43 type 2 (67 surgeries) and 6 type 3 (8 surgeries). Overall, treatment resulted in high VWF:Act and FVIII levels, defined as ≥0.20 IU/mL above predefined levels. In patients with type 1 VWD, respectively, 65% and 91% of trough VWF:Act and FVIII levels were higher than target levels. In patients with type 2 and type 3 VWD, respectively, 53% and 57% of trough VWF:Act and 72% and 73% of trough FVIII levels were higher than target level. Furthermore, FVIII accumulation over time was observed, while VWF:Act showed a declining trend, leading to significantly higher levels of FVIII than VWF:Act. CONCLUSION: High VWF:Act and accumulation of FVIII were observed after perioperative FVIII-based replacement therapy in patients with VWD, both underlining the necessity of personalization of dosing regimens to optimize perioperative treatment.

Plasma levels of plasminogen activator inhibitor-1 and bleeding phenotype in patients with von Willebrand disease.

INTRODUCTION: von Willebrand disease (VWD) is the most common inherited bleeding disorder. In VWD patients, large variations in bleeding tendency are observed, which cannot be completely explained by the variation in von Willebrand factor levels or activities. Thus, there must be additional factors, for instance, changes in fibrinolysis that have an effect on the variation in bleeding tendency in VWD patients. AIM: To investigate whether plasminogen activator inhibitor-1 (PAI-1) level influences the variation in bleeding tendency in VWD patients. METHODS: PAI-1 antigen levels were measured in the plasma of 633 patients with moderate or severe VWD who participated in the 'Willebrand in the Netherlands' (WiN) study, a nationwide multicentre cross-sectional study. Bleeding severity was assessed using the Tosetto bleeding score. RESULTS: PAI-1 levels increased with age (Spearman's rho: 0.225, P < 0.001) and were higher in men (23 [IQR 12-60] vs. 20 [IQR 10-44] ng mL-1 in women, P = 0.039), whereas the bleeding score was higher in women (11 [IQR 7-17] vs. 9 [IQR 5-14] ng mL-1 in men, P = 0.002). After adjustment for age and sex by stratification, PAI-1 level and bleeding score were negatively correlated (Spearman's rho: -0.170, P = 0.017) in the group of 196 young (age ≤ 45 year) female VWD patients, accounting for 31% of our study population. CONCLUSION: In young female VWD patients, we observed that low PAI-1 levels were associated with a higher bleeding score, which may partly explain the observed variability in bleeding phenotype in VWD patients.

A diagnostic approach to mild bleeding disorders.

Mild inherited bleeding disorders are relatively common in the general population. Despite recent advances in diagnostic approaches, mild inherited bleeding disorders still pose a significant diagnostic challenge. Hemorrhagic diathesis can be caused by disorders in primary hemostasis (von Willebrand disease, inherited platelet function disorders), secondary hemostasis (hemophilia A and B, other (rare) coagulant factor deficiencies) and fibrinolysis, and in connective tissue or vascular formation. This review summarizes the currently available diagnostic methods for mild bleeding disorders and their pitfalls, from structured patient history to highly specialized laboratory diagnosis. A comprehensive framework for a diagnostic approach to mild inherited bleeding disorders is proposed.

Needle-knife sphincterotomy guided by a biliary endoprosthesis in Billroth II gastrectomy patients.

BACKGROUND AND STUDY AIMS: All available techniques for performing endoscopic sphincterotomy in Billroth II gastrectomy patients have their limitations, and no standard technique has emerged. A new technique, needle-knife sphincterotomy guided by a thin (7 Fr) biliary endoprosthesis, is described here that overcomes some of the limitations of other techniques. PATIENTS AND METHODS: The technique was attempted in 19 nonselected patients during a three-year period. The results were retrospectively assessed. The outcome variables were the achievement of an adequate sphincterotomy and complications. RESULTS: An adequate sphincterotomy could be performed without much technical difficulty in 18 of the 19 patients. There was one complication, a retroperitoneal leakage, that settled with conservative treatment. CONCLUSIONS: In patients with Billroth II anastomoses, endoprosthesis-guided sphincterotomy is a new and relatively easy procedure, which is especially attractive once selective bile duct cannulation has been achieved. This technique allows the performance of sphincterotomy as a well-controlled procedure, and may, therefore, be safer than nonguided techniques. In contrast to previously reported guided techniques using nasobiliary cannulas, the endoprosthesis technique does not necessitate withdrawing and reinserting the endoscope.

Endoscopic sphincterotomy and biliary drainage in patients with cholangitis due to common bile duct stones.

OBJECTIVES: In a prospective study, we analyzed 95 consecutive patients undergoing endoscopic papillotomy (EP) for cholangitis due to common bile duct (CBD) stones; our purpose was to evaluate the risk factors influencing the complication rate due to cholangitis, with special attention to the clinical history. METHODS: Patients with previous gastric surgery or EP were excluded. Complications subsequent to sphincterotomy were recorded over a 3-month period. RESULTS: In patients with persistent cholangitis before EP, the risk for complications due to cholangitis increased with increasing delay between the onset of cholangitis and biliary drainage. In patients with a good response to antibiotics before EP, the delay in biliary drainage did not influence the risk of complications. After complete CBD stone removal, the morbidity (42% vs. 4%, p = 0.001) and the mortality (8% vs. 0%, NS) due to cholangitis were much higher in 12 patients with progressive cholangitis for > 3 days before biliary drainage, compared with 73 cases who had experienced a good response to antibiotics before EP and/or early drainage (< 3 days) after the onset of cholangitis. Two patients with advanced cholangitis and septic shock at the time of EP died < 12 h after completed sphincterotomy with CBD stone removal. Three patients with retained CBD stones and failed biliary drainage after EP experienced disastrous morbidity (100% vs. 9%, p < 0.01) and mortality (67% vs. 1%, p < 0.01) due to cholangitis, compared with 85 patients without retained CBD stone(s). CONCLUSIONS: We recommend emergency biliary drainage in all patients presenting with calculous cholangitis who are severely ill with continuous fever for several days. Emergency nasobiliary drainage without EP or after a limited EP may be a safer treatment in patients with (impending) septic shock. We believe that a more conservative approach is justified in patients presenting with symptoms of mild cholangitis, restricting emergency biliary drainage for those who do not respond rapidly (< 24 h) to antibiotics. Further emergency surgical or percutaneous biliary drainage should be performed immediately on patients in whom CBD stones are retained, after EP and drainage fails, especially if a stone is left impacted distally.

Endoscopic papillotomy for common bile duct stones: factors influencing the complication rate.

In a prospective study, the complications observed in 242 consecutive patients after endoscopic sphincterotomy for common bile duct stones were recorded over a period of up to three months. Patients with previous gastric surgery, papillotomy, or additional pancreato-biliary disease other than gallbladder stones were excluded. The overall complication rate was 14%, 74% of these complications being moderate or severe. The complication rate due to cholangitis was higher in (1) the group with retained stones following complete papillotomy and without biliary drainage, and (2) the group with failed precut papillotomy and drainage after cholangiography, both compared to patients with successful drainage (75% vs. 2.6%: p < 0.001 and 40% vs. 2.6%: p = 0.001 respectively). Both pancreatitis and retroperitoneal air leakage occurred in 1.7% of cases. They were more frequently observed in patients with a smaller diameter (< 10 mm) in the distal common bile duct (5.6% vs. 0%: p = 0.007 for pancreatitis, and 2.8% vs. 1.2%; n.s. for perforation) and especially following precut papillotomy (13.0% for pancreatitis and 8.7% for perforation), which had to be performed more often in these patients. Bleeding following sphincterotomy was relatively frequent when the papilla was located at the lower rim of or inside a diverticulum, compared to patients without a diverticulum (16.2% vs. 2.7%: p = 0.004 and 26.7% vs. 2.7%: p < 0.001 respectively). When the papilla was located inside diverticula, both the rate of perforation and bleeding increased following precut papillotomy, compared with standard papillotomy only (33% vs. 0%, n.s., and 33% vs. 22%, n.s.).(ABSTRACT TRUNCATED AT 250 WORDS)

Endoscopic papillotomy in biliary tract pain and fluctuating cholestasis with common bile duct dilatation and small gallbladder stones.

In patients suspected of having functional disorders of the papilla it is often difficult to establish the indications whether or not to perform endoscopic papillotomy (EP). We report on thirty-two consecutive patients referred for endoscopic retrograde cholangiopancreatography who all had longstanding biliary tract pain and episodes of liver enzyme elevation indicating cholestasis. Further features were: 1) a dilated common bile duct (CBD) after cholecystectomy (n = 11) or 2) a dilated CBD without or with larger (greater than cystic duct diameter) gallbladder stones (n = 6) or 3) multiple small gallbladder stones, with a normal or dilated CBD, in patients with signs of acute gallstone pancreatitis or in whom elective cholecystectomy was not indicated (n = 15). No CBD stones, organic obstruction or other disorders were found in these patients. Without further diagnostic procedures, EP was routinely performed. The laboratory (up to 3 months) and clinical findings (2 to 4 years follow up) showed improvement in all patients undergoing EP. We conclude that immediate EP appears justified in these selected patients.

Prognostic implications of the localization of carcinoma in the head of the pancreas.

Between 1974 and 1989, 411 patients with pathologically and anatomically proven carcinoma of the head of the pancreas underwent endoscopic retrograde cholangiopancreatography (ERCP). According to the localization of the tumor, these patients were divided into those with a cranially, centrally (periductally), caudally, or indeterminately localized tumor. In cranially localized tumors, extrahepatic metastases and vessel invasion were absent or resectable in 53% and 46%, respectively. The tumor was resectable in 41% of cases. If a patient with a cranially localized tumor could not be operated curatively for secondary reasons, the prognosis was better than for tumors with another localization. If there was unresectable vessel invasion and the tumor was not resectable, the 0% survival rate was reached at 33 months. Of the curatively operated patients, 26% were alive at 36 months after the start of complaints. Of the centrally or periductally localized tumors, there were no liver metastases in 73%. Extrahepatic metastases and vessel invasion were absent or resectable in 57% and 53%, respectively. The tumor was resectable in 48% of cases. If there was unresectable vessel invasion or the tumor was unresectable, the 0% survival rate was reached after 18 months. These tumors have maximal chances at curative resection. Of the curatively operated patients, 31% were alive at 36 months after the start of complaints. In caudally localized tumors, there were liver metastases in 59%, unresectable other abdominal metastases in 93%, unresectable vessel invasion in 91%, and the tumor was unresectable in 96%. In patients with an unresectable vessel invasion or an unresectable tumor, the 0% survival rate was reached after 33 months; 3% of these patients were operated curatively. Indeterminately localized tumors had liver metastases in 77%, unresectable extrahepatic metastases in 90%, unresectable vessel invasion in 95%, and the tumor was unresectable in 91%. Only one of the 44 patients (2%) could be operated curatively.

Malignant common bile duct obstruction: factors influencing the success rate of endoscopic drainage.

The problems encountered in draining the bile ducts endoscopically in 148 patients with malignant obstruction of the mid or distal common bile duct and/or the papilla were assessed. Endoscopically visible extrinsic invasion of the papilla by a malignancy in the pancreatic head, with or without duodenal stenosis, appeared to be the major reason for the failure to insert a stent. The larger a tumor in the pancreatic head the greater the chance of invasion of the papillary region. This appeared to be evident for tumors restricted to the non-uncinate region of the pancreatic head. We would recommend primary percutaneous biliary drainage or surgery when the size of a proven malignancy restricted to the non-uncinate region of the pancreatic head is 5 cm or more, or when diagnostic duodenoscopy reveals extrinsic invasion of the papilla of Vater, or severe duodenal involvement with stenosis.

Fluorescein-diacetate, a fluorescent dye compound stain for rapid evaluation of the viability of mammalian oocytes prior to in vitro studies.

A method for a quantitative measurement of the fluorescence activity of porcine egg cells is described. The non-polar fluorescein-diacetate molecules enter the cell, are hydrolyzed by cell esterases, and fluorescein is produced. This polar compound can not leave the cell because it is unable to pass through the intact cell membrane, and it therefore accumulates in the cytoplasm of the cell. Damaged cells however show a distinct loss of fluorescein through the cell membrane. With the aid of a fluorescence microscope, a photometer and a recorder, the amount of radiated light can be measured. The advantages of this method in oocyte research are briefly discussed.

The relation between sperm quality and the effect of ouabain on the motility of spermatozoa.

This paper reports the results of an investigation into the effect of ouabain on spermatozoa which have suffered from aging, sudden changes in temperature and deep-freezing. Normal spermatozoa of different boars under standard conditions show an evident variation in ouabain sensitivity. A definite relation could be established between the fertility of the semen of a boar and the ouabain sensitivity of this semen. Spermatozoa exposed to aging, sudden temperature changes or deep-freezing, showed a greater sensitivity for 10(-3)M ouabain than corresponding controls. We concluded that factors which are harmful to membrane quality of spermatozoa can be revealed by exposing them to ouabain.