Perioperative diagnosis and impact of acquired von Willebrand syndrome in infants with congenital heart disease.

Acquired von Willebrand syndrome (aVWS) has been reported in patients with congenital heart diseases associated with shear stress caused by significant blood flow gradients. Its etiology and impact on intraoperative bleeding during pediatric cardiac surgery have not been systematically studied. This single-center, prospective, observational study investigated appropriate diagnostic tools of aVWS compared with multimer analysis as diagnostic criterion standard and aimed to clarify the role of aVWS in intraoperative hemorrhage. A total of 65 newborns and infants aged 0 to 12 months scheduled for cardiac surgery at our tertiary referral center from March 2018 to July 2019 were included in the analysis. The glycoprotein Ib M assay (GPIbM)/von Willebrand factor antigen (VWF:Ag) ratio provided the best predictability of aVWS (area under the receiver operating characteristic curve [AUC], 0.81 [95% CI, 0.75-0.86]), followed by VWF collagen binding assay/VWF:Ag ratio (AUC, 0.70 [0.63-0.77]) and peak systolic echocardiographic gradients (AUC, 0.69 [0.62-0.76]). A cutoff value of 0.83 was proposed for the GPIbM/VWF:Ag ratio. Intraoperative high-molecular-weight multimer ratios were inversely correlated with cardiopulmonary bypass (CPB) time (r = -0.57) and aortic cross-clamp time (r = -0.54). Patients with intraoperative aVWS received significantly more fresh frozen plasma (P = .016) and fibrinogen concentrate (P = .011) than those without. The amounts of other administered blood components and chest closure times did not differ significantly. CPB appears to trigger aVWS in pediatric cardiac surgery. The GPIbM/VWF:Ag ratio is a reliable test that can be included in routine intraoperative laboratory workup. Our data provide the basis for further studies in larger patient cohorts to achieve definitive clarification of the effects of aVWS and its potential treatment on intraoperative bleeding.

Multi-Modal Characterization of the Coagulopathy Associated With Extracorporeal Membrane Oxygenation.

OBJECTIVES: Extracorporeal membrane oxygenation is used to stabilize severe cardiocirculatory and/or respiratory failure. However, extracorporeal membrane oxygenation is associated with a coagulopathy characterized by thromboembolic and hemorrhagic complications. This study aimed to characterize the pathomechanism of the extracorporeal membrane oxygenation-associated coagulopathy and identify options to optimize its monitoring and therapy. DESIGN: Prospective observational clinical trial. SETTING: ICU of a university hospital. PATIENTS: Patients treated with venovenous extracorporeal membrane oxygenation (n = 10) due to acute respiratory distress syndrome and patients treated with venoarterial extracorporeal membrane oxygenation (n = 8) due to cardiocirculatory failure. One patient per group (venovenous extracorporeal membrane oxygenation or venoarterial extracorporeal membrane oxygenation) had surgery before extracorporeal membrane oxygenation. INTERVENTIONS: Blood was sampled before, and 1, 24, and 48 hours after extracorporeal membrane oxygenation implantation. Point-of-care tests (thrombelastometry/platelet aggregometry), conventional coagulation tests, whole blood counts, and platelet flow cytometry were performed. MEASUREMENTS AND MAIN RESULTS: Even before extracorporeal membrane oxygenation, plasmatic coagulation and platelet aggregation were impaired due to systemic inflammation, liver failure, anticoagulants (heparins, phenprocoumon, apixaban), and antiplatelet medication. During extracorporeal membrane oxygenation, hemodilution and contact of blood components with artificial surfaces and shear stress inside extracorporeal membrane oxygenation additionally contributed to coagulation and platelet defects. Fibrinogen levels, fibrin polymerization, platelet activation, and microparticle release were increased in venovenous extracorporeal membrane oxygenation compared to venoarterial extracorporeal membrane oxygenation patients. Point-of-care results were available faster than conventional analyses. Bleeding requiring blood product application occurred in three of 10 venovenous extracorporeal membrane oxygenation patients and in four of eight venoarterial extracorporeal membrane oxygenation patients. No thrombotic events were observed. In-hospital mortality was 30% for venovenous extracorporeal membrane oxygenation and 37.5% for venoarterial extracorporeal membrane oxygenation patients. CONCLUSIONS: The extracorporeal membrane oxygenation-associated coagulopathy is a multifactorial and quickly developing syndrome. It is characterized by individual changes of coagulation parameters and platelets and is aggravated by anticoagulants. The underlying factors of the extracorporeal membrane oxygenation-associated coagulopathy differ between venovenous extracorporeal membrane oxygenation and venoarterial extracorporeal membrane oxygenation patients and are best diagnosed by a combination of point-of-care and conventional coagulation and platelet analyses. Therapy protocols for treating extracorporeal membrane oxygenation-associated coagulopathy should be further validated in large-scale prospective clinical investigations.

Disease progression and defects in primary hemostasis as major cause of bleeding in multiple myeloma.

BACKGROUND AND OBJECTIVES: In patients with multiple myeloma (MM), unexpected bleeding complications remain a major issue. Since routine coagulation parameters are often inconspicuous, diagnosis and treatment of the underlying coagulation disorders are challenging. PATIENTS AND METHODS: In our single-center observational study, we analyzed 164 patients with MM for coagulation disorders and bleeding complications. RESULTS: Prolonged closure times (CTs), measured by PFA-100, were the most common, abnormal coagulation test, found in 66% of bleeding patients vs 5% in non-bleeding, followed by qualitative defects of von Willebrand factor (VWF:CB/VWF:Ag ratios), found in 34% vs 1% in the non-bleeding group. Increased serum free light chains (SFLC) and SFLC ratios were significantly associated with prolonged CTs and acquired von Willebrand syndrome (AVWS). Prolonged CTs and AVWS were associated with disease progression, determined by dynamics of SFLC ratios (P < .001), serum creatinine level (P = .013), Beta-2 microglobulin (P = .03), LDH (P = .016), and bone marrow infiltration (P < .001). Of note, response to myeloma therapy was frequently correlated with normalization of coagulation parameters. CONCLUSIONS: Bleeding complications in MM are predominantly caused by defects in primary hemostasis and associated with disease progression. In a peri-interventional workup, determination of CTs and VWF:CB/VWF:Ag ratios are of significant importance to assess bleeding risk.

Low plasma protein Z levels are associated with an increased risk for perioperative bleedings.

BACKGROUND AND OBJECTIVES: Protein Z (PZ) deficiency has been implicated both in bleeding diatheses and in thrombophilia. Considering its ambiguous nature and the conflicting clinical data so far, we set out to evaluate the impact of low PZ on perioperative bleeding in patients who underwent surgical (ENT) interventions involving a high risk of bleeding. PATIENTS AND METHODS: After exclusion of other coagulation disorders, 154 Patients were stratified into quartiles according to PZ plasma concentrations to evaluate the relation between PZ and bleeding complications. RESULTS: Low PZ levels were associated with increased blood loss (P < .001), increased need for blood transfusions (P < .001), and a higher rate of surgical revisions (P = .009) in a concentration-dependent fashion. Low PZ caused earlier (within 24 hours) and repetitive bleedings (P = .005). The number of major bleeding episodes was significantly increased when low PZ was combined with bleeding history (P < .05). Finally, ROC analyses confirmed the predictive value of low PZ for bleeding complications and PZ-thresholds for clinical practice were determined. CONCLUSIONS: Low PZ appears to be an underestimated risk factor for perioperative bleeding. Determination of PZ plasma concentrations might be useful in the preoperative workup in patients with a bleeding history, when detailed clotting analyses remain inconclusive.

Acquired von Willebrand syndrome is common in infants with systemic-to-pulmonary shunts: Retrospective case-series.

Background: Although acquired von Willebrand syndrome (aVWS) has been described in congenital heart disease before, anatomical features leading to aVWS with characteristic reduction or loss of high molecular weight von Willebrand multimers (HMWM) are not well known. This study assesses the prevalence and effects of aVWS in infants with systemic-to-pulmonary shunts (SPS). Methods: This retrospective single-center study analyzes diagnostic data of infants with complex congenital heart defects requiring palliation with SPS. During the study period between 12/15-01/17 fifteen consecutive patients were eligible for analysis. Results of von Willebrand factor antigen (VWF:Ag), collagen binding activity (VWF:CB) and von Willebrand factor multimer analysis were included. Results: In all 15 patients with SPS an aVWS could be found. Blood samples were collected between 5 and 257 days after shunt implantation (median 64 days). None of the patients demonstrated increased bleeding in everyday life. However, 6 out of 15 patients (40%) showed postoperative bleeding complications after SPS implantation. Following shunt excision multimeric pattern normalized in 8 of 10 (80%) patients studied. Conclusions: This study shows that in patients undergoing SPS implantation aVWS might emerge. Pathogenesis can be explained by shear stress resulting from turbulent flow within the shunt. Knowledge of aVWS existence is important for the consideration of replacement therapy with von Willebrand factor containing products and antifibrinolytic treatment in bleeding situations. Implementation of methods for rapid aVWS detection is required to achieve differentiated hemostatic therapy and reduce the risk of complications caused by empiric replacement therapy.

Acquired coagulopathy caused by intoxication with the superwarfarin-type anticoagulant rodenticide flocoumafen.

A 28 year-old heretofore healthy woman was transferred to our hospital with a two-month history of recurring episodes of bleeding. Administration of vitamin K and prothrombin complex concentrates in the transferring hospital had only temporarily corrected both the markedly elevated international normalized ratio (INR) and the prolonged activated partial thromboplastin time (aPTT). The patient's medical and family history revealed no reason for these abnormalities. Our laboratory analyses revealed a sustained deficiency of vitamin K-dependent clotting factors. Presence of an acquired inhibitor of clotting factors was excluded. Thus we suspected, intoxication with an anticoagulant rodenticide. Liquid chromatography-mass spectrometry (LC-MS/MS) revealed pharmacologically active concentrations of flocoumafen, a rodenticide belonging to the superwarfarin family, in the patient's serum. While the long elimination half-life of superwarfarins is well described in rodents, information on pharmacokinetics in humans is not yet available. Therefore, patient management was not limited to prolonged administration of vitamin K, but also included repeated measurements of flocoumafen serum levels. During follow-up visits, clotting tests remained normal and flocoumafen levels gradually decreased, reaching the limit of quantification after 48 days. Based on the repeated measurements of flocoumafen serum levels, a half-life of 6.7 days was estimated in our patient, which is in clear contrast to the 220 days reported in rodents. Thus, monitoring flocoumafen serum concentrations in affected patients may provide a rational basis for the duration of vitamin K substitution and adequate follow-up intervals.

[Vaginal bleeding as symptom of a medical emergency--pitfalls of therapy with new oral anticoagulants - case 5/2014]. / Vaginale Blutung als Symptom eines internistischen Notfalls--Tücken der Therapie mit neuen oralen Antikoagulanzien - Fall 5/2014.

HISTORY AND ADMISSION FINDINGS: A 90-year-old female patient treated with dabigatran for atrial fibrillation presented emergently with a spontaneous vaginal bleeding due to endometrium carcinoma. INVESTIGATIONS: Laboratory analysis revealed azotemia consistent with acute-on-chronic renal failure. Coagulation was deranged (prolongation of activated partial thromboplastin time (aPTT) by 3.5-fold, international normalized ratio (INR) 7.8) due to a massive accumulation of dabigatran (measured plasma concentration 2230 ng/ml). DIAGNOSIS, TREATMENT AND COURSE: Vaginal bleedings were treated with external tamponade. Hemodialysis treatment was commenced due to uremia and dabigatran accumulation. Over night, the patient was dialysed with a SLED (sustained low efficiency dialysis) regimen. After volume resuscitation renal function promptly ensued indicating prerenal azotemia as a cause of renal failure. After two more hemodialysis sessions dabigatran concentrations were no longer detecable and this was paralleled by normalization of coagulation tests. CONCLUSIONS: Dabigatran can accumulate massively during acute renal failure and evoke a life-threatening bleeding diathesis. Dabigatran can be removed with low efficient dialysis (such as SLED).

[Unusual cause of macrohematuria in a 29-year-old woman]. / Seltene Ursache einer Makrohämaturie bei einer 29-jährigen Patientin.

HISTORY AND ADMISSION FINDINGS: We report on the case of a young women presenting with macrohaematuria, petechiae and strong headaches. INVESTIGATIONS: Laboratory showed a thrombotic microangiopathy with helmet cells, increased LDH levels (>600 U/l), and thrombocytopenia (<40,000/µl). DIAGNOSIS, TREATMENT AND COURSE: Due to strong haemolytic activity and headache with blurred vision, immediate plasma separation with fresh frozen plasma was commenced. Markedly decreased ADAMTS13 activity and detection of anti-ADAMTS13 antibodies were consistent with the diagnosis of idiopathic thrombotic thrombocytopenic purpura. In total, 11 plasma separations were required to stop disease activity. In parallel, immunosuppressive therapy using glucocorticoids was initiated. The patient was discharged from the hospital in a good general condition and with normalized laboratory findings 26 days after hospitalization. CONCLUSIONS: All patients with anemia and thrombocytopenia should be tested for haemolysis and helmet cells. An early diagnosis and initiation of necessary therapy are determining for the clinical outcome.

Management of disseminated intravascular coagulopathy with direct factor Xa inhibitor rivaroxaban in Klippel-Trénaunay syndrome.

Klippel-Trénaunay syndrome (KTS) is a rare congenital anomaly characterized by malformation of lymph and blood vessels as well as growth disturbance of soft tissue and bone. The clinical picture is variable and associated with an increased risk of thromboembolic events mediated by intravascular coagulopathy in venous malformations. Here, we report on a male patient with KTS suffering from recurrent deep vein thrombosis (DVT) and life-threatening bleeding due to consumptive coagulopathy. Furthermore, we describe the successful long-term anticoagulant management with rivaroxaban.

[Severe hemorrhage in a patient with metastatic colorectal cancer - case 8/2012]. / Schwere Blutungen bei einer Patientin mit metastasierendem Kolonkarzinom - Fall 8/2012.

HISTORY AND ADMISSION FINDINGS: We report on a 65-year-old female patient with a recent diagnosis of adenocarcinoma of the sigmoid colon and massive hematochezia in the context of a general bleeding disorder. INVESTIGATIONS: Disseminated malignant disease with hepatic metastases as well as bone marrow involvement was demonstrated. Moreover, circulating tumor cells were demonstrated by flow cytometry. The patient had right lower quadrant abdominal pain due to a spontaneous psoas intramuscular hematoma. DIAGNOSIS, TREATMENT AND COURSE: At the time of admission to our hospital, the patient displayed microangiopathic hemolytic anemia and secondary hyperfibrinolysis with a pronounced bleeding tendency. Moreover, there was an acute renal failure which improved with fluid resuscitation. With immediate chemotherapy consisting of 5-fluorouracil, folinic acid and oxaliplatin (FOLFOX regimen) and cetuximab initiated with the second course, plasmatic coagulation could be stabilized. Consequently, treatment with tranexamic acid, fibrinogen, fresh frozen plasma as well as red blood cell and platelet infusions could be stopped. Continuation of chemotherapy was possible on an outpatient basis and the further course was associated with a good quality of life until her near end. The patient died at home 7 months after initial diagnosis of her colon cancer due to progressive disease with CNS metastases. CONCLUSIONS: Disseminated intravascular coagulation with microangiopathic hemolysis and secondary hyperfibrinolysis is a rare albeit possible event in disseminated colorectal cancer, especially when the bone marrow is involved. Treatment of the underlying cause is the most important therapeutic measure.

Human plasma thrombopoietin levels are regulated by binding to platelet thrombopoietin receptors in vivo.

BACKGROUND: Data from several studies support the hypothesis that thrombopoietin (TPO) plasma levels are regulated via circulating platelet (PLT) numbers by binding to PLT TPO receptors (TPO-Rs). In this study, PLT numbers and TPO plasma levels were measured following the transfusion of unmanipulated, sham-saturated, and TPO-R-saturated PLT preparations to provide additional in vivo evidence for this regulatory mechanism. STUDY DESIGN AND METHODS: Following in vitro experiments to characterize pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) binding characteristics, PLT numbers and TPO plasma levels were measured following the transfusion of unmanipulated, sham-saturated, and TPO-R-saturated PLT preparations in thrombocytopenic patients. Sham-saturated and TPO-R-saturated PLTs were prepared by a 1-hour incubation without and with 40 ng per mL of PEG-rHuMGDF, respectively, and subsequent washing and resuspension. RESULTS: In vitro, 2.72 +/- 0.8 ng of PEG-rHuMGDF per 1 x 10(8) PLTs was bound within 1 hour of incubation. No additional PEG-rHuMGDF was bound following a second incubation with PEG-rHuMGDF, and bound PEG-rHuMGDF was not released over time. In vivo, TPO plasma levels decreased significantly (p < 0.001), by 30.7 +/- 5.8 and 20.9 +/- 2.1 percent after transfusion of unmanipulated and sham-saturated PLT preparations, respectively. However, TPO plasma levels were unaffected after the transfusion of TPO-R-saturated PLTs despite comparable transfusion-induced PLT count increases. CONCLUSION: These data strongly support the concept that binding to PLT TPO-R is directly involved in human TPO plasma level regulation in vivo.