Very Late Scaffold Thrombosis: Intracoronary Imaging and Histopathological and Spectroscopic Findings.

BACKGROUND Bioresorbable scaffolds provide transient lumen support followed by complete resorption. OBJECTIVES This study examined whether very late scaffold thrombosis (VLScT) occurs when resorption is presumed to be nearly complete. METHODS Patients with VLScT at 3 tertiary care centers underwent thrombus aspiration followed by optical coherence tomography (OCT). Thrombus aspirates were analyzed by histopathological and spectroscopic examination. RESULTS Between March 2014 and February 2015, 4 patients presented with VLScT at 44 (case 1), 19 (cases 2 and 4), and 21 (case 3) months, respectively, after implantation of an Absorb Bioresorbable Vascular Scaffold 1.1 (Abbott Laboratories, Abbott Park, Illinois). At the time of VLScT, all patients were taking low-dose aspirin, and 2 patients were also taking prasugrel. OCT showed malapposed scaffold struts surrounded by thrombus in 7.1%, 9.0%, and 8.9% of struts in cases 1, 2, and 4, respectively. Scaffold discontinuity with struts in the lumen center was the cause of malapposition in cases 2 and 4. Uncovered scaffold struts with superimposed thrombus were the predominant findings in case 3. OCT percent area stenosis at the time of VLScT was high in case 1 (74.8%) and case 2 (70.9%) without evidence of excessive neointimal hyperplasia. Spectroscopic thrombus aspirate analysis showed persistence of intracoronary polymer fragments in case 1. CONCLUSIONS VLScT may occur at advanced stages of scaffold resorption. Potential mechanisms specific for VLScT include scaffold discontinuity and restenosis during the resorption process, which appear delayed in humans; these findings suggest an extended period of vulnerability for thrombotic events.

Treatment of optic neuritis with erythropoietin (TONE): a randomised, double-blind, placebo-controlled trial-study protocol.

INTRODUCTION Optic neuritis leads to degeneration of retinal ganglion cells whose axons form the optic nerve. The standard treatment is a methylprednisolone pulse therapy. This treatment slightly shortens the time of recovery but does not prevent neurodegeneration and persistent visual impairment. In a phase II trial performed in preparation of this study, we have shown that erythropoietin protects global retinal nerve fibre layer thickness (RNFLT-G) in acute optic neuritis; however, the preparatory trial was not powered to show effects on visual function. METHODS AND ANALYSIS Treatment of Optic Neuritis with Erythropoietin (TONE) is a national, randomised, double-blind, placebo-controlled, multicentre trial with two parallel arms. The primary objective is to determine the efficacy of erythropoietin compared to placebo given add-on to methylprednisolone as assessed by measurements of RNFLT-G and low-contrast visual acuity in the affected eye 6 months after randomisation. Inclusion criteria are a first episode of optic neuritis with decreased visual acuity to ≤0.5 (decimal system) and an onset of symptoms within 10 days prior to inclusion. The most important exclusion criteria are history of optic neuritis or multiple sclerosis or any ocular disease (affected or non-affected eye), significant hyperopia, myopia or astigmatism, elevated blood pressure, thrombotic events or malignancy. After randomisation, patients either receive 33 000 international units human recombinant erythropoietin intravenously for 3 consecutive days or placebo (0.9% saline) administered intravenously. With an estimated power of 80%, the calculated sample size is 100 patients. The trial started in September 2014 with a planned recruitment period of 30 months. ETHICS AND DISSEMINATION TONE has been approved by the Central Ethics Commission in Freiburg (194/14) and the German Federal Institute for Drugs and Medical Devices (61-3910-4039831). It complies with the Declaration of Helsinki, local laws and ICH-GCP. TRIAL REGISTRATION NUMBER NCT01962571.

Dysregulation of alternative splicing of coagulation factor V results in bleeding disorder, east Texas type and other disorders of hemostasis

The studies completed herein explore different phenotypes related to the genetic defects that predispose individuals to a disruption of normal hemostasis. In the first study, a novel autosomal dominant bleeding disorder, which is characterized by excessive bleeding with trauma or surgery and menorrhagia in affected women, was studied in a large family (16 affected individuals) from east Texas. Affected members had a prolongation of their PT and/or aPTT, but normal clinical coagulation studies. Previous linkage analysis by Kuang et. al. (2001) mapped the defective gene to 1g23-24 (LODmax 7.22), which contains the gene for coagulation factor V (FV). I identified an alteration (A2440G) in the FV gene in exon 13 that segregated with the disease and was not present in 62 controls. Interestingly, this alteration resulted in a 22-fold up-regulation of a novel alternative splicing variant in patients' RNA versus controls. This translated into a similar fold increase in a 250-kDa isoform of FV seen in patients' plasma versus controls. A recombinant of this splicing event exhibited an increased sensitivity to cleavage by activated protein C (APC) that was more striking in the presence of PS. In addition, this novel isoform had increased APC cofactor activity, thus increasing the degradation of FVIIIa. These data indicated that A2440G up-regulates an alternatively spliced transcript of FV, and increases a FV isoform that hinders coagulation as opposed to promoting it like its wild-type counterpart. ^ The second study reports the largest screening to date of African Americans in two independent cohorts for a rare prothrombin variant, C20209T, which is suspected to be associated with thrombotic disease. The Texas Medical Center Genetics Resource (TexGen) Stroke DNA repository revealed 1.67% (Fisher p=0.27) of African American stroke patients were heterozygous for the 20209*T allele. Screening of the Atherosclerosis Risk in Communities Study (ARIC) cohort (n=3470) for the 20209*T allele revealed a population prevalence of 0.58% in individuals of African American descent; however, all associations with thrombotic disease were negative. Analysis of these two independent cohorts revealed that, unlike its neighbor G20210A, the C20209T variant does not increase the risk of thrombotic events in the African American population. ^

Variability in the international normalised ratio (INR) in patients with antiphospholipid syndrome and positive lupus anticoagulant: should the INR targets be higher?

El síndrome antifosfolípido es un desorden autoinmune caracterizado por hipercoagulabilidad que requiere terapia anticoagulante como pilar fundamental, siendo la warfarina el tratamiento de elección en los casos que requieren manejo por largos periodos. Sin embargo, los pacientes con anticoagulante lúpico positivo representan un reto porque tienen mayor riesgo de presentar eventos trombóticos, sumado a que el seguimiento con el International Normalized Ratio (INR) no es confiable, ya que estos anticuerpos generan interferencia con las pruebas de laboratorio basadas en fosfolípidos, como es el caso del tiempo de protrombina (PT) con INR basal prolongado, incluso antes del inicio de la terapia anticoagulante. Por tal razón, se ilustra el caso de una paciente con síndrome antifosfolípido primario y anticoagulante lúpico positivo quien ha presentado múltiples episodios trombóticos, a pesar de recibir terapia anticoagulante. Además se hace una revisión de la literatura disponible y se postulan nuevas metas de INR en estos pacientes diferentes de las que se plantean actualmente.

Treatment of thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP), characterized by thrombocytopenia and microangiopathic haemolytic anaemia, was almost universally fatal until the introduction of plasma exchange (PE) therapy in the 1970s. Based on clinical studies, daily PE has become the first-choice therapy since 1991. Recent findings may explain its effectiveness, which may include, in particular, the removal of anti-ADAMTS13 autoantibodies and unusually large von Willebrand factor multimers and/or supply of ADAMTS13 in acquired idiopathic or congenital TTP. Based on currently available data, the favoured PE regimen is daily PE [involving replacement of 1-1.5 times the patient's plasma volume with fresh-frozen plasma (FFP)] until remission. Adverse events of treatment are mainly related to central venous catheters. The potential reduction of plasma related side-effects, such as transfusion-related acute lung injury (TRALI) or febrile transfusion reactions by use of solvent-detergent treated (S/D) plasma instead of FFP is not established by controlled clinical studies. Uncontrolled clinical observations and the hypothesis of an autoimmune process in a significant part of the patients with acquired idiopathic TTP suggest a beneficial effect of adjunctive therapy with corticosteroids. Other immunosuppressive treatments are not tested in controlled trials and should be reserved for refractory or relapsing disease. There is no convincing evidence for the use of antiplatelet agents. Supportive treatment with transfusion of red blood cells or platelets has to be evaluated on a clinical basis, but the transfusion trigger for platelets should be very restrictive. Further controlled, prospective studies should consider the different pathophysiological features of thrombotic microangiopathies, address the prognostic significance of ADAMTS13 and explore alternative exchange fluids to FFP, the role of immunosuppressive therapies and of new plasma saving approaches as recombinant ADAMTS13 and protein A immunoadsorption.

Multiple thromboembolic events in fetofetal transfusion syndrome in triplets contributing to the understanding of pathogenesis of hydranencephaly in combination with polymicrogyria

Over the last 180 years, several theories concerning the origin of hydranencephaly have been proposed with an emphasis on infectious, aplastic, and vascular etiologies. In this report, we present a case of triplets with fetofetal transfusion syndrome of which 2 fetuses (1 and 2) developed almost similar hydranencephaly, whereas the third exhibited the features of a fetus papyraceus (3). In the monochorial triamniotic placenta, multiple arteriovenous anastomoses were detected, representing a probable route for the transmission of thrombi originating from fetus 3 causing visceral lesions in fetus 2. Hydranencephaly was histologically characterized by necrosis, macrophage invasion, and endothelial proliferation. In addition, polymicrogyria was seen in fetuses 1 and 2. The combination of multiple visceral thromboembolic events and the death of fetus 3 approximately in the 11th week of gestation suggested a vascular thrombotic pathogenesis of hydranencephaly. Polymicrogyria can be considered as postmigratory laminar necrosis. Our findings contribute to the pathogenetic understanding of combined hydranencephaly and polymicrogyria.

Pancreatitis preceding acute episodes of thrombotic thrombocytopenic purpura-hemolytic uremic syndrome: report of five patients with a systematic review of published reports

BACKGROUND AND OBJECTIVES: The thrombotic thrombocytopenic purpura-hemolytic uremic syndromes (TTP-HUS) have diverse etiologies, clinical manifestations, and risk factors, but the events that may trigger acute episodes are often unclear. We describe the occurrence of TTP-HUS following pancreatitis and consider whether pancreatitis may be a triggering event for acute episodes of TTP-HUS. DESIGN AND METHODS: We report on three patients from the Oklahoma Registry and two patients from Northwestern University who had an acute episode of TTP-HUS following pancreatitis. A systematic review of published case reports was performed to identify additional patients who had TTP-HUS following pancreatitis. RESULTS. In each of our five patients there was an apparent etiology of alcoholism or common bile duct obstruction for the pancreatitis and no evidence of TTP-HUS when the pancreatitis was diagnosed. Two patients had severe ADAMTS13 deficiency with an inhibitor; in one of these patients TTP-HUS recurred following a subsequent recurrent episode of pancreatitis. The systematic review identified 16 additional patients who had TTP-HUS following pancreatitis; recurrent TTP-HUS occurred in three of these patients following a subsequent episode of recurrent pancreatitis. In all 21 patients, the interval between the diagnosis of pancreatitis and TTP-HUS was short (1-13 days; median, 3 days). The three Oklahoma patients represent approximately 1% of the 356 patients in the Registry. INTERPRETATION AND CONCLUSIONS: These observations suggest that in some patients pancreatitis, a disorder that results in an intense systemic inflammatory response, may be a triggering event for acute episodes of TTP-HUS.

Acute pancreatitis and thrombotic thrombocytopenic purpura

Thrombotic thrombocytopenic purpura (TTP) has multiple clinical manifestations and risk factors, but the events that actually trigger acute episodes of TTP are often unclear. We describe the case of a 56-year-old woman who presented with clinical signs and symptoms of TTP and acute pancreatitis. We discuss whether pancreatitis was due to ischemic pancreatic damage caused by microvascular platelet clumping in the frame of TTP, or whether acute pancreatitis, a disorder that results in an intense systemic inflammatory response, may be a triggering event for acute episodes of TTP.

Clinical outcomes after platelet transfusions in patients with thrombotic thrombocytopenic purpura

BACKGROUND: Reports of deterioration and death after platelet (PLT) transfusions in patients with thrombotic thrombocytopenic purpura (TTP) have led to recommendations that they should not be given except for life-threatening hemorrhage. STUDY DESIGN AND METHODS: Published reports of PLT transfusions in patients with TTP were systematically reviewed and data from the Oklahoma TTP-HUS Registry, an inception cohort of 382 consecutive patients, 1989 through 2007, were analyzed. RESULTS: A systematic review identified 34 publications describing outcomes of patients with TTP after PLT transfusions: 9 articles attributed complications to PLT transfusions, 4 suggested that they may be safe, and 21 articles did not comment about a relation between PLT transfusions and outcomes. Fifty-four consecutive patients from the Oklahoma TTP-HUS Registry were prospectively analyzed. ADAMTS13 activity was less than 10 percent in 47 patients; also included were 7 patients whose activity was not measured but who may have been deficient. Thirty-three (61%) patients received PLT transfusions. The frequency of death was not different between the two groups (p = 0.971): 8 (24%) patients who received PLT transfusions died (thrombosis, 5; hemorrhage, 1; sepsis, 2) and 5 (24%) patients who did not receive PLT transfusions died (thrombosis, 4; hemorrhage, 1). The frequency of severe neurologic events was also not different (p = 0.190): 17 (52%) patients who received PLT transfusions (in 5 of these 17 patients, neurologic events only occurred before PLT transfusions) and 7 (33%) patients who did not receive PLT transfusions. CONCLUSION: Evidence for harm from PLT transfusions in patients with TTP is uncertain.

On the Dark Side of Therapies with Immunoglobulin Concentrates: The Adverse Events

Therapy by human immunoglobulin G (IgG) concentrates is a success story ongoing for decades with an ever increasing demand for this plasma product. The success of IgG concentrates on a clinical level is documented by the slowly increasing number of registered indication and the more rapid increase of the off-label uses, a topic dealt with in another contribution to this special issue of Frontiers in Immunology. A part of the success is the adverse event (AE) profile of IgG concentrates which is, even at life-long need for therapy, excellent. Transmission of pathogens in the last decade could be entirely controlled through the antecedent introduction by authorities of a regulatory network and installing quality standards by the plasma fractionation industry. The cornerstone of the regulatory network is current good manufacturing practice. Non-infectious AEs occur rarely and mainly are mild to moderate. However, in recent times, the increase in frequency of hemolytic and thrombotic AEs raised worrying questions on the possible background for these AEs. Below, we review elements of non-infectious AEs, and particularly focus on hemolysis and thrombosis. We discuss how the introduction of plasma fractionation by ion-exchange chromatography and polishing by immunoaffinity chromatographic steps might alter repertoire of specificities and influence AE profiles and efficacy of IgG concentrates.

Caplacizumab for Acquired Thrombotic Thrombocytopenic Purpura.

BACKGROUND Acquired thrombotic thrombocytopenic purpura (TTP) is caused by aggregation of platelets on ultralarge von Willebrand factor multimers. This microvascular thrombosis causes multiorgan ischemia with potentially life-threatening complications. Daily plasma exchange and immunosuppressive therapies induce remission, but mortality and morbidity due to microthrombosis remain high. METHODS Caplacizumab, an anti-von Willebrand factor humanized single-variable-domain immunoglobulin (Nanobody), inhibits the interaction between ultralarge von Willebrand factor multimers and platelets. In this phase 2, controlled study, we randomly assigned patients with acquired TTP to subcutaneous caplacizumab (10 mg daily) or placebo during plasma exchange and for 30 days afterward. The primary end point was the time to a response, defined as confirmed normalization of the platelet count. Major secondary end points included exacerbations and relapses. RESULTS Seventy-five patients underwent randomization (36 were assigned to receive caplacizumab, and 39 to receive placebo). The time to a response was significantly reduced with caplacizumab as compared with placebo (39% reduction in median time, P=0.005). Three patients in the caplacizumab group had an exacerbation, as compared with 11 patients in the placebo group. Eight patients in the caplacizumab group had a relapse in the first month after stopping the study drug, of whom 7 had ADAMTS13 activity that remained below 10%, suggesting unresolved autoimmune activity. Bleeding-related adverse events, most of which were mild to moderate in severity, were more common with caplacizumab than with placebo (54% of patients vs. 38%). The frequencies of other adverse events were similar in the two groups. Two patients in the placebo group died, as compared with none in the caplacizumab group. CONCLUSIONS Caplacizumab induced a faster resolution of the acute TTP episode than did placebo. The platelet-protective effect of caplacizumab was maintained during the treatment period. Caplacizumab was associated with an increased tendency toward bleeding, as compared with placebo. (Funded by Ablynx; ClinicalTrials.gov number, NCT01151423.).