A Series of 14 Polish Patients with Thrombotic Events and PC Deficiency-Novel c.401-1G>A PROC Gene Splice Site Mutation in a Patient with Aneurysms

Objectives: Protein C (PC) deficiency is an inherited thrombophilia with a prevalence of 0.5% in the general population and 3% in subjects with a first-time deep vein thrombosis (DVT). Here we report a series of 14 PC-deficient Polish patients with comprehensive clinical and molecular characteristics, including long-term follow-up data and a deep mutational analysis of the PROC gene. Patients and Methods: Fourteen unrelated probands (mean ± SD age 43.8 ± 13.0 years) with suspicion of PC deficiency, who experienced thromboembolic events and a majority of whom received anticoagulants (92.8%), were screened for PROC mutations by sequencing the nine PROC exons and their flanking intron regions. Results: Ten probands (71.4%) had missense mutations, two patients (14.3%) carried nonsense variants, and the other two subjects (14.3%) had splice-site mutations, the latter including the c.401-1G>A variant, reported here for the very first time. The proband carrying the c.401-1A allele had a hepatic artery aneurysm with a highly positive family history of aneurysms and the absence of any mutations known to predispose to this vascular anomaly. Conclusion: A novel detrimental PROC mutation was identified in a family with aneurysms, which might suggest yet unclear links of thrombophilia to vascular anomalies, including aneurysms at atypical locations in women. The present case series also supports data indicating that novel oral anticoagulants (NOACs) are effective in PC deficient patients.

Recurrent Cerebral Venous Thrombosis Treated with Direct Oral Anticoagulants in a Japanese Man with Hereditary Protein C Deficiency

We herein report a case involving a 32-year-old Japanese man with recurrent cerebral venous thrombosis due to hereditary protein C deficiency. He was admitted to our hospital with impaired consciousness. Brain magnetic resonance imaging demonstrated high intensities diffusely along the bilateral sulci and magnetic resonance venography revealed left transverse sinus and superior sagittal sinus stenoses. His father had a history of cerebral infarction and venous thrombosis. The protein C activity level examined by chromogenic synthetic substrate assay was markedly reduced. He was diagnosed with protein C deficiency, and a genetic analysis revealed a heterozygous mutation at exon 3 c.199G>A,p.Glu67Lys on the protein C gene. Four months later, at his second admission, he had transient aphasia, and his protein C activity was under 10%. We switched warfarin to the direct oral anticoagulants edoxaban. He remains fully recovered with no adverse events after the administration of edoxaban for a year. Direct oral anticoagulants may be a new tool for treating cerebral venous thrombosis due to hereditary protein C deficiency.

Protein C deficiency related obscure gastrointestinal bleeding treated by enteroscopy and anticoagulant therapy

Obscure gastrointestinal bleeding is an uncommonly encountered and difficult-to-treat clinical problem in gastroenterology, but advancements in endoscopic and radiologic imaging modalities allow for greater accuracy in diagnosing obscure gastrointestinal bleeding. Ectopic varices account for less than 5% of all variceal bleeding cases, and jejunal variceal bleeding due to extrahepatic portal hypertension is rare. We present a 47-year-old man suffering from obscure gastrointestinal bleeding. Computed tomography of the abdomen revealed multiple vascular tufts around the proximal jejunum but no evidence of cirrhosis, and a visible hypodense filling defect suggestive of thrombus was visible in the superior mesenteric vein. Enteroscopy revealed several serpiginous varices in the proximal jejunum. Serologic data disclosed protein C deficiency (33.6%). The patient was successfully treated by therapeutic balloon-assisted enteroscopy and long-term anticoagulant therapy, which is normally contraindicated in patients with gastrointestinal bleeding. Diagnostic modalities for obscure gastrointestinal bleeding, such as capsule endoscopy, computed tomography enterography, magnetic resonance enterography, and enteroscopy, were also reviewed in this article.

Protein C and protein S deficiency - practical diagnostic issues

Protein C (PC) and protein S (PS) are vitamin K-dependent glycoproteins, that act as natural anticoagulants. The proteolytic activation of PC by thrombin occurs on the surface of endothelial cells and involves thrombomodulin and endothelial PC receptor. In the presence of PS, phospholipids and calcium, activated PC (APC) inactivates membrane bound factors V (FVa) and FVIIIa by their cleavage at the specific arginine residues. PC and PS deficiencies are inherited as autosomal dominant disorders associated with recurrent venous thromboembolism (VTE) and, in most cases, derived from heterozygous missense mutations (78% and 63%, respectively). Heterozygous PC deficiency is found in 6% of families with inherited thrombophilia, in 3% of patients with a first-time deep vein thrombosis (DVT) and 0.2-0.3% of healthy individuals. The PS deficiency is detected more commonly than PC deficiency and its prevalence has been estimated with a less than 0.5% in the general European population and 2% to 12% of selected groups of thrombophilic patients. Approximately 75% of PC-deficient patients have type I deficiency and 95% of PS-deficient patients develop type I and type III of PS deficiency. The diagnosis of PC and PS deficiencies is challenging, many preanalytical and analytical factors may affect the PC/PS levels. Molecular analysis of the PC and PS genes (PROC and PROS1, respectively) involves direct gene sequencing and if negative, multiplex ligation-dependent probe amplification (MLPA) method. Patients with low PC and PS levels and the known mutation within PROC or PROS1 genes combined with other genetic or environmental thrombosis factors are at increased risk of recurrent thromboembolic events and require lifelong oral anticoagulation.

Case report: perioperative use of protein c concentrate for protein C deficiency in THA

BACKGROUND

Perioperative management of patients with heterozygous protein C deficiency is challenging because of the competing risks of bleeding and recurrent thrombosis.

CASE DESCRIPTION

We report the case of a 74-year-old man with protein C deficiency and heterozygous prothrombin G20210A gene mutation who had a successful left THA with perioperative administration of human zymogen protein C concentrate in addition to anticoagulation with enoxaparin.

LITERATURE REVIEW

Several studies have reported the use of protein C concentrate in severe sepsis-associated purpura fulminans in patients with severe congenital protein C deficiency who have had thrombotic events. We reviewed studies and case reports pertinent to the treatment of patients with protein C deficiency, especially in the perioperative setting. We report the case of a patient undergoing THA in whom we used human zymogen protein C concentrate.

PURPOSES AND CLINICAL RELEVANCE

THA, a particularly high-risk procedure, is associated with a 40% to 70% incidence of venographic deep venous thrombosis and a 2% to 3% incidence of symptomatic deep venous thrombosis. These risks are greater in people with thrombophilic defects such as protein C deficiency. The use of human zymogen protein C in our patient with heterozygous protein C deficiency during the perioperative period of a THA was associated with no evidence of excessive bleeding, hematoma, deep venous thrombosis, or pulmonary embolism.

Use of protein C concentrate in neonatal period

Levels of protein C, low at birth, physiologically Increase until six months of age and achieve the adult range after puberty. Protein C deficiency may be congenital or acquired. Severe protein C deficiency is a rare autosomal recessive disorder that usually presents in neonatal period with purpura fulminans. Acquired protein C deficiency may be caused by increased consumption (e.g., asphyxia, overt DIC, severe infection without overt DIC, acute VTE) or by decreased synthesis of the active carboxylated protein (e.g. administration of vitamin K antagonists, severe hepatic synthetic disfunction). Two different formulations of protein C are available: recombinant human activated protein C (rhAPC) and human plasma-derived viral-inactivated protein C. It is known that in septic patients replacement therapy with rhAPC reduces mortality but is associated with an increased risk of bleeding. During the neonatal period, when a higher risk of bleeding exists, the human plasma-derived viral-inactivated protein C concentrate may represent an effective therapeutic option. In fact, its administration results effective both in severe congenital and acquired forms of protein C deficiency.

High long-term absolute risk of recurrent venous thromboembolism in patients with hereditary deficiencies of protein S, protein C or antithrombin

Hereditary deficiencies of protein S, protein C and antithrombin are known risk factors for first venous thromboembolism. We assessed the absolute risk of recurrence, and the contribution of concomitant thrombophilic defects in a large cohort of families with these deficiencies. Annual incidence of recurrence was estimated in 130 deficient patients, with separate estimates for those with each of protein S, protein C, and antithrombin deficiency, and in eight non-deficient patients with prior venous thromboembolism. All patients were also tested for factor V Leiden, prothrombin G20210A, high levels of factors VIII, IX and XI, and hyperhomocysteinemia. There were 81 recurrent events among 130 deficient patients. Median follow-up was 4.6 years. Annual incidences (95% confidence interval) of recurrent venous thromboembolism were 8.4% (5.8-11.7) for protein S deficiency, 6.0% (3.9-8.7) for protein C deficiency, 10.0% (6.1-15.4) for antithrombin deficiency, and overall 7.7% (6.1-9.5). Relative risk of recurrence in patients with a spontaneous versus provoked first event was 1.5 (0.95-2.3). Cumulative recurrence rates at 1, 5 and 10 years were 15%, 38% and 53%. Relative risk of recurrence with concomitant defects was 1.4 (0.7-2.6) (1 defect) and 1.4 (0.8-2.7) (> or =2 defects). Annual incidence was 1.0% (0.03-5.5) in eight non-deficient patients. Annual incidence of major bleeding in deficient patients on oral anticoagulant treatment was 0.5% (0.2-1.0). We conclude that patients with a hereditary protein S, protein C or antithrombin deficiency appear to have a high absolute risk of recurrence. This risk is increased after a first spontaneous event, and by concomitance of other thrombophilic defects.

Hirudin treatment for multiple thromboses in a preterm infant with inherited thrombophilia

Thromboembolic events in preterm infants constitute a serious problem in neonatal intensive care. In most cases, treatment with low-molecular-weight heparin offers a sufficient therapy of thrombotic events. We report the case of a severely sick male preterm infant with a heterozygous factor V Leiden mutation and protein C deficiency. The infant developed multiple thromboses despite adequate anticoagulation with enoxaparin and was in a life-threatening situation. Treatment with hirudin prevented the occurrence of new thromboses without causing bleeding complications. After 2 weeks hirudin was discontinued and low-molecular-weight heparin therapy was started again. A successive recanalization of the vast majority of affected vessels was observed within the following 6 months. Despite some minor neurologic sequelae and a slight delay in neuro-motor development, the 2.5-year-old boy is in a healthy condition. This case demonstrates that hirudin can be an effective alternative anticoagulant in neonates and infants refractory to heparin treatment. Efficacy and safety issues of hirudin treatment, however, need to be evaluated in randomized trials.

Reduction of high fetal loss rate by anticoagulant treatment during pregnancy in antithrombin, protein C or protein S deficient women

Hereditary thrombophilia is associated with an increased risk of fetal loss. Assuming that fetal loss is due to placental thrombosis, anticoagulant treatment might improve pregnancy outcome. In an observational family cohort study, we prospectively assessed the effects of anticoagulant drugs on fetal loss rates in women with hereditary deficiencies of antithrombin, protein C or protein S. The cohort contained 376 women (50 probands and 326 deficient or non-deficient relatives). Probands were consecutive deficient patients with venous tromboembolism. Thromboprophylaxis during pregnancy was recommended in deficient women, irrespective of prior venous thromboembolism, and in non-deficient women with prior venous thromboembolism. Outcome of first pregnancy was analysed in 55 eligible women. Of 37 deficient women, 26 (70%) received thromboprophylaxis during pregnancy, compared with three of 18 (17%) non-deficient women. Fetal loss rates were 0% in deficient women with thromboprophylaxis versus 45% in deficient women without (P = 0.001) and 7% in non-deficient women without thromboprophylaxis (P = 0.37). The adjusted relative risk of fetal loss in women who received thromboprophylaxis versus women who did not was 0.07 (95% confidence interval 0.001-0.7; P = 0.02). Our data suggest that anticoagulant treatment during pregnancy reduces the high fetal loss rate in women with hereditary deficiencies of antithrombin, protein C or protein S.

Right-to-left interatrial shunt with hypoxemia caused by a right atrial thrombus

A right-to-left shunt in the presence of normal pulmonary artery pressure is an unusual cause of hypoxemia in an adult who has a patent foramen ovale. We report a rare case of such a shunt-the result of a right atrial thrombus that formed in a hypercoagulable patient after placement of an indwelling central venous catheter for chemotherapy. In order to ascertain the nature of the right atrial mass and to decrease the risk of systemic embolization, the thrombus was surgically removed with the patient on cardiopulmonary bypass.

Protein C concentrations in severe sepsis: an early directional change in plasma levels predicts outcome

INTRODUCTION

Protein C, because of its central role in hemostasis, plays an integral role in the host response to infection. Protein C depletion, resulting from increased consumption, degradation, and/or decreased synthesis, is characteristic of sepsis and has been shown to predict morbidity and mortality. The objective of this study was to determine whether early directional changes in protein C levels correlate with outcome.

METHODS

Patients in the Recombinant Human Activated Protein C Worldwide Evaluation in Severe Sepsis (PROWESS) clinical trial were assessed and categorized by baseline protein C (n = 1574). Deficiency was categorized as: severe deficiency, protein C levels < or = 40% of normal protein C activity (n = 615, 39% of patients); deficient, protein C levels 41-80% of normal protein C activity (n = 764, 48.5% of patients); and normal, >80% of normal protein C activity (n = 195, 12.4% of patients). Logistic regression analysis of 28-day mortality for placebo patients was used to investigate whether baseline and day 1 protein C levels were independent risk factors for mortality. The impact of treatment with drotrecogin alfa (activated) (DrotAA) was also assessed.

RESULTS

Protein C levels at baseline and day 1 were independent risk factors in placebo patients. If baseline protein C levels of severely deficient placebo patients remained < or = 40% at day 1 their odds of death increased (odds ratio = 2.75, P < 0.0001), while if levels improved to >40% by day 1 their risk of death decreased (odds ratio = 0.43, P = 0.03). If baseline protein C levels of placebo patients were >40% but decreased by > or = 10% on day 1, their risk of death increased (odds ratio = 1.87, P = 0.02). DrotAA treatment improved protein C levels by day 1 compared with placebo (P = 0.008) and reduced the risk of death in severely deficient (< or = 40%) patients at baseline. Treatment also decreased the number of severely protein C deficient (= 40%) patients and decreased the number of deficient (41-80%) patients and normal (>80%) patients who had a > or = 10% decrease in protein C levels by day 1.

CONCLUSION

Baseline protein C levels were an independent predictor of sepsis outcome. Day 1 changes in protein C, regardless of baseline levels, were also predictive of outcome. The association of DrotAA treatment, increased protein C levels, and improved survival may partially explain the mechanism of action.

Process scale-up studies for protein C separation using IMAC

Protein C (PC) is the pivotal anticoagulant and antithrombotic in the human coagulation cascade. PC deficiency can disturb the blood hemostasis and cause thrombosis, inhibiting oxygen transport to tissue, and resulting in major medical problems such as deep vein thrombosis (DVT). The current treatment can cause bleeding and other major medical problems. PC circulates in the blood as a zymogen and is only activated when and where it is needed. PC is a safe anticoagulant without harmful side effects. A combination of ion-exchange chromatography and IMAC IDA-Cu was studied for the relatively large scaled PC separation from Cohn fraction IV-1. Almost half of the active PC was recovered by using this process. In future work, we will verify the linearity of the IMAC column scale-up. This process can be used to produce PC from Cohn fraction IV-1 at large quantities and low cost to treat PC-deficient patients.

Acute myeloblastic leukemia in a patient with hereditary protein C deficiency

The patient had been diagnosed with hereditary protein C deficiency. She recently developed acute myeloblastic leukemia (AML). Chemotherapy for AML by cytosine arabinoside, aclarubicin followed by granulocyte colony-stimulating factor (CAG) was started. Disseminated intravascular coagulation (DIC) was observed, however thromboembolic complication was not observed during the hospital course. Hematological remission was not obtained, and the patient died of pseudomembranous pancolitis. Whether the development of these rare disorders of hereditary protein C and AML are coincidental, or involve a causal relationship remains unknown.

Protein C and/or S deficiency presenting as peripheral arterial insufficiency

Although protein C and/or S deficiency has frequently been associated with venous thromboembolic events, instances of arterial thromboses have been reported. However, the exact incidence of protein C and/or S deficiency in patients with peripheral arterial insufficiency has not been established. Furthermore, given the lack of adequate studies to define the natural history and angiographic findings of these patients, the treatment has not been well delineated. Therefore, we conducted a prospective study to investigate the prevalence, characteristic angiographic findings and optimal treatments in patients with peripheral arterial insufficiency associated with protein C and/or S deficiency. Between September 2000 and August 2004, 133 patients who presented with peripheral arterial insufficiency underwent hypercoagulability tests before the initiation of any treatments. Of these, 11 patients (8.3%) with protein C and/or S deficiency were included in this study. There were nine males and two females. The ages ranged from 38 years to 72 years (mean 57 years). All patients showed characteristic angiographic findings: long segment thrombotic occlusion of a main peripheral artery without evidence of atherosclerosis or with mild atherosclerotic changes in the aorta and other major arterial trees. Surgical or endovascular procedures were performed in nine patients: bypass graft in four, thrombectomy in four and catheter-directed thrombolysis in one. Conservative treatment with full anticoagulation was performed in two patients. All patients received pre- and post-operative anticoagulation. Except for one amputated case, clinical and vascular laboratory improvements were achieved in 10 patients. Mean follow-up period was 21 months (range 4-45 months). However, one patient, in whom re-vascularization surgery was performed successfully, discontinued warfarin therapy himself at 10 months after surgery, graft occlusion and limb loss occurred at 30 months after surgery. This initial experience suggests that protein C and/or S deficiency may be an independent risk factor for peripheral arterial insufficiency. Patients who present with peripheral arterial insufficiency and protein C and/or S deficiency demonstrate characteristic angiographic findings. Once the diagnosis of protein C and/or S deficiency is made, patients should be treated with life-long anticoagulation.

New insights into the protein C pathway: potential implications for the biological activities of drotrecogin alfa (activated)

It has been hypothesized that the protein C pathway is a pivotal link between the inflammation and coagulation cascades. The demonstration that a survival benefit is associated with administration of drotrecogin alfa (activated) (recombinant human activated protein C [APC]) in severe sepsis patients has provided new insights into the protein C pathway. APC was originally identified based on its antithrombotic properties, which result from the inhibition of activated Factors V and VIII. In the early 1990s, any potential anti-inflammatory properties of APC were thought to relate primarily to its inhibition of thrombin generation. However, the mid-1990s saw the identification of the endothelial protein C receptor (EPCR), which has subsequently been shown to be neither endothelial specific nor protein C specific, but has a primary function as a cofactor for enhancing the generation of APC or behaving as an APC receptor. Thus, the potential biologic activities of APC can be classed into two categories related either to the limiting of thrombin generation or to cellular effects initiated by binding to the EPCR. Intracellular signaling initiated by binding of APC to its receptor appears to be mediated by interaction with an adjacent protease-activated receptor (PAR), or by indirect activation of the sphingosine 1-phosphate pathway. Based mostly on in vitro studies, binding of APC to its receptor on endothelial cells leads to a decrease in thrombin-induced endothelial permeability injury, while such binding on blood cells, epithelial cells, and neurons has been shown to inhibit chemotaxis, be anti-apoptotic, and be neuroprotective, respectively. In the Recombinant Human Activated Protein C Worldwide Evaluation in Severe Sepsis (PROWESS) study, drotrecogin alfa (activated) was associated with improved cardiovascular function, respiratory function, and a prevention of hematologic dysfunction. This article discusses the way in which the interactions of APC may alter the microcirculation.

Modeling behavior of protein C during and after subcutaneous administration

Protein C is an important blood factor protein that regulates the blood coagulation process. Deficiency of protein C can lead to excessive coagulation that results in lack of tissue oxygenation, causing conditions such as deep vein thrombosis, pulmonary embolism, and stroke. Human protein C has been approved as a treatment for congenital protein C deficiency; however, the therapy requires frequent injections, due to the short residence time of the protein. Subcutaneous administration has been examined as an alternative to increase residence time and decrease injection frequency, thereby creating a more patient-friendly dosing regimen. In order to design an efficient injection or infusion protocol for subcutaneously administered proteins, it is important to accurately model the behavior (absorption, distribution, elimination) of these proteins in the body. However, several factors involved in a subcutaneous injection of the protein make modeling this behavior a challenging task. For example, absorption of the drug from the subcutaneous site into the blood stream can be variable depending on the site of injection, physical activity of the patient, etc. Furthermore, degradation of the protein can occur at the site of injection and further modify its absorption. The objective of this work was to demonstrate the utility of frequency response modeling as an alternative method to analyze the behavior of subcutaneously administered protein C. The results of our study indicate that if the dose range yielding the constant clearance of protein C is identified for the patient, models of that type, as presented in our study, can be used to adjust optimal dosing of protein C necessary to reach prescribed levels of the protein in this patient at desired time points, both specified by treatment requirements.

Subcutaneous administration of protein C concentrate

Children born with severe homozygous protein C deficiency do not survive beyond the neonatal period unless they receive protein C replacement. Protein C concentrate (Baxter Biosciences, Vienna) is usually given intravenously via a central venous catheter The authors describe 2 children in whom protein C concentrate was successfully administered by subcutaneous infusion after they had had recurrent central line infections. Alternate daily doses of 250-350 IU/kg resulted in trough protein C levels of > 25 IU/dL. In the follow-up period of 1-2 years neither child has had a thrombotic episode or purpuric skin lesions, and infusions are managed in the home by their parents.

Diagnosis and treatment of a newborn with homozygous protein C deficiency

The case is reported of a seriously affected newborn with homozygous protein C deficiency who developed neonatal purpura fulminans. Foetal ultrasound at 33 wk of gestation revealed ventriculomegaly. The first lesions appeared on the scalp 48 h after birth. She was initially treated with fresh-frozen plasma and, after the diagnosis was confirmed, with purified protein C concentrate. After skin necrosis had healed, therapy was continued with oral warfarin. The infant was homozygous for protein C W380G mutation. Diagnosis at the DNA level gave the parents an option of reliable prenatal diagnosis in their subsequent pregnancy.

CONCLUSION

Difficulties in reaching an accurate diagnosis are discussed since early diagnosis and urgent therapy with protein C replacement are crucial to avoid further damage after delivery.

[Use of protein C concentrate in adult patients with severe sepsis and septic shock]

AIM

The aim of this study is to describe the first experiences on the use of protein C concentrate (PC) in adult patients with severe sepsis and septic shock and clinical contraindications to activated protein C (APC). On the basis of the effectiveness demonstrated by the activated form in sepsis and of the encouraging results expressed in literature of protein C concentrate (PC) mainly about meningococcus fulminating infections, we carried out an observational study on protein C concentrate (PC) with 28-day follow-up and a daily analysis of the hemato-chemical and clinical parameters. Particular attention was paid to the variations in the PC plasma levels, to the modifications of the coagulation system, to the SOFA score as well as to the safety under bleeding risk conditions.

METHODS

The study included 7 patients (5 females and 2 males) either with severe sepsis (2). or septic shock (5); one of them had DIC, with PC plasma levels less than 50%. APC could not be administered because of clinical reasons. Patients' mean age was 60.5 years (43-78), the average SAPS II 52.2 (36-72), the pathologies leading to sepsis were lung infections (3). and peritonitis (4). The average time elapsed between the onset of the organ failure and the beginning of treatment with PC was 27.7 hours (12-42).

RESULTS

Mortality on day 28 was 42.8% (3 deaths), in all patients the PC plasma levels were brought again to the physiological values. Among the biochemical parameters recorded during the PC infusion, was observed in particular a significant decrease of PDFs, a general rise of the platelet count, and a reduction of the lactic acid levels. No adverse reaction or bleeding complication were seen, even if most of the patients' coagulation was altered or at risk due to neurological problems or repeated surgery.

CONCLUSION

In our small number of patients, protein C concentrate has proven to be safe and particularly useful in the control of the coagulopathy triggered and sustained by sepsis.

Successful management of a pregnant woman with heterozygous protein C deficiency using activated protein C concentrate

Heterozygous protein C deficiency frequently causes deep vein thrombosis during pregnancy. We report the successful management of delivery using activated protein C concentrate in a patient with heterozygous protein C deficiency, who developed deep vein thrombosis in mid gestation.

[Replacement therapy with protein C for meningococcal sepsis and fulminant purpura in pediatric patients]

Disseminated intravascular coagulation as associated to sepsis contributes to the development of clinical multiple organ failure by extensive thrombosis in microcirculation vessels. This condition commonly manifests itself in severe meningococcal sepsis. On the skin, its clinical manifestation is extensive purpura with necrotic lesions that usually progress to serious distal ischemia and may call for amputation. A common denominator in these events regarding hemostasis is a depletion of so-called natural anticoagulant proteins, particularly protein C. According to clinical observations replacement therapy with human plasma-derived protein C concentrates has been associated with significantly improved clinical outcome in patients with meningococcal sepsis and fulminant purpura. This paper reports a case of acquired protein C deficiency in a girl with meningococcal sepsis, fulminant purpura, disseminated intravascular coagulation, and septic shock. Fresh plasma therapy was intended to increase consumption coagulopathy-depleted coagulation factors and to provide small amounts of protein C. The inability to restore protein C concentrations above 30%, and the presence of severe thrombopenia in the setting of disseminated intravascular coagulation led to the onset of replacement therapy using a human protein C concentrate (Ceprotin), which increased plasma protein C concentrations and contributed to revert the existing hypercoagulability status. Finally, evidence available in the literature regarding fulminant meningococcal sepsis management using human protein C concentrates and recombinant activated protein C is discussed.

Activated protein C concentrate reverses purpura fulminans in severe genetic protein C deficiency

Severe genetic protein C deficiency is rare and is associated with severe, often fatal thrombosis. The authors report the use of recombinant activated protein C (APC) to treat an episode of purpura fulminans (PF) in a teenage girl with severe protein C deficiency who had developed anaphylaxis to fresh-frozen plasma that was given in the past to treat recurrent episodes of PF. Concomitant with an infusion of APC, 20 microg/kg/h for 10 hours, a d-dimer level that was markedly positive (6,450 ng/mL) prior to the onset of PF decreased to 847 ng/mL following the APC. The teenager was treated with heparin along with warfarin for four days until the INR was more than 3.5 and the d-dimer level was less than 230 ng/mL. At the end of the APC infusion all skin lesions of PF were resolved. There were no adverse reactions to APC. APC was safe and effective for treatment of PF in severe genetic protein C deficiency.

Safety, pharmacokinetics, and pharmacodynamics of drotrecogin alfa (activated) in children with severe sepsis

OBJECTIVE

In a phase 3 trial, recombinant human activated protein C (drotrecogin alfa [activated]) significantly reduced mortality in adult patients with severe sepsis. We have now performed a preliminary analysis of the safety, pharmacokinetics, and pharmacodynamics of drotrecogin alfa (activated) in pediatric patients with severe sepsis.

DESIGN AND SETTING

Open-label, nonrandomized, sequential, 2-part study conducted in 11 medical centers in the United States and United Kingdom.

PATIENTS

Eighty-three pediatric patients with severe sepsis aged term newborn (>or=38 weeks' gestation) to <18 years old.

INTERVENTION

In part 1, drotrecogin alfa (activated) was administered as escalating doses of 6, 12, 24, and 36 micro g/kg per hour for 6 hours for each patient (n = 21). In part 2, drotrecogin alfa (activated) was infused at a rate of 24 micro g/kg per hour for 96 hours in 62 patients.

MAIN OUTCOME MEASURES

Plasma clearance, plasma concentration, D-dimer, protein C, and antithrombin levels were measured, and adverse events were monitored.

RESULTS

The trial enrolled 83 pediatric patients with severe sepsis, aged term newborn (>or=38 weeks' gestation) to <18 years. In part 1, a dose of 24 micro g/kg per hour produced steady-state plasma concentrations of activated protein C similar to those attained in equivalently dosed adult severe sepsis patients. For all pediatric patients dosed at 24 micro g/kg per hour, the median weight-normalized clearance was 0.45 L/hour/kg and the median steady-state concentration was 51.3 ng/mL. The mean plasma half-life was 30 minutes. Weight-normalized clearance in pediatric and adult patients did not differ significantly with age or weight. D-dimer levels decreased 26% from baseline to end of infusion. Baseline levels of protein C and antithrombin increased 79% and 24%, respectively, over the 96-hour treatment period in part 2. The incidence of serious bleeding during infusion and during the entire study period was 2.4% and 4.8%, respectively.

CONCLUSIONS

Pediatric patients with severe sepsis manifest sepsis-induced coagulopathy including protein C deficiency comparable to that seen in adults with severe sepsis. The pharmacokinetics, pharmacodynamic effects, and safety profile of drotrecogin alfa (activated) in pediatric patients are similar to those previously published for adult patients. A large, phase 3, randomized, placebo-controlled study is ongoing to confirm these results and formally assess the safety and efficacy of drotrecogin alfa (activated) in children.

Late onset of clinical symptoms and recurrent ecchymotic skin lesions in a 12-year-old girl with a severe double heterozygous protein C deficiency

The authors describe a 12-year-old girl with late-onset clinical symptoms due to severe protein C deficiency. Protein C gene analysis showed double heterozygosity for two distinct mutations, associated with type I protein C deficiency. Her parents and only brother were also evaluated. Coumarin-induced skin necrosis was a recurrent feature during oral anticoagulation therapy, forcing her physicians to treat her with nadroparin (Fraxiparin) for only a few months.

Myeloid/natural killer cell precursor acute leukemia accompanied by homozygous protein C deficiency

A patient with myeloid/natural killer (NK) cell precursor acute leukemia who was also homozygous for protein C deficiency was treated and showed a complete remission while he simultaneously received low molecular weight heparin. He presented with fever spikes, lymphadenopathy, and a bulky tumor of the anterior mediastinum. A bone marrow aspirate showed the infiltration of immature lymphoblastoid cells. The patient's diagnosis was determined to be myeloid/NK cell precursor acute leukemia by morphologic and immunophenotypic analysis (CD7(+)CD33(+)CD34(+)CD56(+)). The patient developed a thrombosis in his jugular vein on cannulation of the internal jugular vein. An examination of the serum levels and the activities of proteins C and S demonstrated a slight decrease in the protein C level but an undetectable protein C activity. The patient received the diagnosis of homozygous protein C deficiency, because both parents were found to have heterozygous protein C activity. Treatment of the patient's leukemia included induction chemotherapy (Ara-C and idarubicin) with concomitant administration of low molecular weight heparin for his homozygous protein C deficiency. He achieved a complete remission without expressing any thrombosis during the course of chemotherapy. To our knowledge, this is the first case ever described in which acute myeloid leukemia was complicated with homozygous protein C deficiency.

[Obstetric aspects of hereditary thrombophilias: epidemiology, complications and prophylaxis]

The study gives a survey of literature on obstetric aspects of hereditary thrombophilias e.i. factor V Leiden, prothrombin gene 20210A mutation, antithrombin III deficiency, protein C/protein S deficiency, and hyperhomocysteinemia. All types of thrombophilia cause similar pathomorphological changes in placenta and decidua (high number of infarcts and microclots, decidual vasculopathia) as well as insufficient invasion of cytotrophoblast in spiral arteries. The study also discusses prophylactic rules: application of low molecular weight heparin and non-fractionated heparin in prophylaxis and in hyperhomocysteinemia application of folic acid.

Human protein C: new preparations. Effective replacement therapy for some clotting disorders

(1) Depending on its severity, congenital protein C deficiency can cause a variety of problems, such as increasing the frequency of venous thrombosis in high risk situations; recurrent venous thrombosis; skin necrosis at the start of treatment with a vitamin K antagonist; and severe thrombotic events in neonates. For many years the only available replacement treatment consisted of fresh frozen plasma which, among other adverse effects, carries a risk of hypervolemia. (2) Two human protein C concentrates prepared from donated blood have been given marketing authorisation in Europe for intravenous replacement therapy (Ceprotin from Baxter, and Protexel from LFB). (3) Their clinical files contain only retrospective case series (22 children with severe deficiency treated with Ceprotin; and 10 patients of various ages and with different degrees of severity treated with Protexel). The two preparations have not been compared with each other. (4) In patients with severe protein C deficiency, including neonates, replacement therapy with human protein C is effective, especially for treating cutaneous thrombosis and preventing thrombosis in high risk situations. (5) In patients with moderate deficiency, a short-course of human protein C prophylaxis reduces the frequency of thrombosis in high risk situations. (6) In long-term prophylaxis, human protein C replacement therapy, added to ongoing (but inadequately effective) vitamin K antagonist therapy, seems to reduce the risk of recurrent venous thrombosis even though it has some constraints. (7) The adverse effects of the two preparations are poorly documented. Allergic reactions and bleeding have been reported. Human protein C is a blood product, and therefore carries a risk of infection. (8) Ceprotin offers a small advantage, being available in two dose strengths: for a given dose the volume injected is halved. (9) In practice, Ceprotin and Protexel are the reference drugs for replacement therapy of constitutional protein C deficiency, although their indications and adverse effects should be better documented.

Thromboprophylaxis with low molecular weight heparin in thrombophilia-complicated pregnancy

We treated three thrombophilia-complicated pregnant women (two antiphospholipid antibody syndrome, one protein C deficiency) with low molecular weight heparin (dalteparin). All three pregnancies including one twin pregnancy ended in live births without a decrease in bone mineral density. This treatment modality was effective and safe preventing thrombosis during their pregnancies.

Protein C deficiency. Biatrial thrombus presentation

Protein C deficiency is an inherited thrombophilia presented in adults with venous thrombosis at different sites. Symptomatic biatrial thrombus presentation of protein C deficiency has not, to my knowledge, been described. This report investigates a man with protein C deficiency who presented with dyspnea and recurrent attacks of dizziness associated with biatrial thrombus. Complete disappearance of the symptoms and thrombi was observed within less than 3 weeks of anticoagulation.

Human recombinant activated protein C in meningococcal sepsis

A 19-year-old woman presented with purpura fulminans and septic shock; subsequently, progressive coagulopathy, widespread purpura fulminans associated with meningococcemia, severe shock, respiratory, and renal failure developed. This clinical course was associated with depletion of functional protein C levels to < 5%. We describe her clinical course and therapy with human recombinant activated protein C.

[Perioperative management of a patient with purpura fulminans syndrome due to protein C deficiency]

PURPOSE

Protein C is a vitamin K-dependent anticoagulant and homozygous protein C deficiency is a rare fatal thrombotic disease. This report describes the perioperative management of homozygous protein C deficiency in a patient who underwent a total of three surgical procedures under general anesthesia and the successful use of activated protein C concentrate.

CLINICAL FEATURES

A female baby, who developed disseminated intravascular coagulation and purpura fulminans shortly after birth, was diagnosed as purpura fulminans syndrome due to homozygous protein C deficiency. At one month of age, she suffered bilateral retinal detachment and glaucoma due to retinal hemorrhage. After marked improvement of her condition after administration of activated protein C concentrate, she underwent a left iridectomy and implantation of a Broviak catheter under general anesthesia. Her intraoperative course was uncomplicated but, on postoperative day four, she presented another episode of massive cutaneous necrosis and gangrene. Activated protein C concentrate was administered again, with good results. She underwent replacement of a Broviak catheter at four months of age, and right iridectomy for glaucoma at eight months. Both were uneventful.

CONCLUSION

The perioperative management of homozygous protein C deficiency and purpura fulminans requires appropriate measures for thromboembolic prophylaxis. Sufficient iv fluid administration is necessary. Attention should be paid to decrease the risk of tissue compression such as that associated with positioning, blood pressure cuff, and endotracheal intubation, which may cause necrosis over pressure points. Replacement therapy with activated protein C concentrate appears safe and effective. The anesthetic management is reviewed and discussed.

Clinical management of protein C deficiency

Protein C (PC) is a vitamin K-dependent plasma protein that is structurally similar to other coagulation factors such as prothrombin and Factor X. PC is converted to its active anticoagulant form by a thrombin-thrombomodulin complex on the surface of capillary endothelial cells. Activated PC (APC) prevents the formation of blood clots by specifically inactivating factors Va and VIIIa in the clotting cascade. Both acquired and hereditary forms of PC deficiency exist, with hereditary further categorised as heterozygous, homozygous as well as doubly heterozygous. Patients suffering from symptomatic heterozygous PC deficiency present with purpura fulminans, venous thrombosis and/or pulmonary embolism. Homozygous PC deficiency is usually associated with the development of severe and often fatal, purpura fulminans and disseminated intravascular coagulation (DIC) during the neonatal period. Various therapeutic options have been described for long-term management of severe heterozygous and homozygous PC deficiencies. For the treatment of heterozygous PC deficiency, oral anticoagulation with a coumarin derivative or heparin therapy remains standard therapy. Homozygous patients may be treated with fresh frozen plasma (FFP) and iv. PC concentrate or coumarin derivatives. Other therapeutic options for the treatment of hereditary PC deficiency include the use of low-molecular weight heparin (LMWH), steroids and liver transplantation. Maintenance of a symptom-free life depends on response to therapy. Patients responding well to treatment can expect normalisation of haemostasis as well as improvement of microcirculation and resolution of purpura fulminans.

An open-label study of the role of adjuvant hemostatic support with protein C replacement therapy in purpura fulminans-associated meningococcemia

Activated protein C (APC) is a natural anticoagulant that plays a pivotal role in coagulation homeostasis. Severe inherited or acquired deficiency results in a clinical syndrome called purpura fulminans. In addition, APC also appears to have potent cytokine-modifying properties and is protective in animal models of sepsis. The dual functional properties of APC are particularly relevant to severe meningococcemia, where acquired PC deficiency is accompanied by multiorgan failure and purpura fulminans. The authors conducted an open-label prospective study assessing the efficacy of PC replacement therapy in patients with severe meningococcal septicemia, purpura fulminans, and multiorgan failure. The morbidity and mortality were compared with predicted morbidity using the Glasgow Meningococcal Septicemia Prognostic Score. Thirty-six patients with a mean age of 12 years (range 3 months to 72 years) were enrolled in the study. The mean +/- SD for plasma PC was 18 +/- 7 IU/mL. PC was significantly lower than antithrombin or protein S and was also significantly lower than PC levels in a cohort of patients who developed meningococcemia without multiorgan failure and purpura fulminans. A total of 3 of 36 (8%) patients died, which compares favorably with predicted mortality of 18 of 36 (50%). Amputations were required in 4 of 33 (12%) survivors and in 2 of 31 (6.5%) patients who received PC within 24 hours of admission into the hospital, in comparison with the predicted amputation rate of 11 of 33 (30%). In conclusion, PC replacement therapy in severe meningococcal septicemia was associated with a reduction in predicted morbidity and mortality. The beneficial effect of PC replacement may reflect both the anticoagulant and anti-inflammatory properties of the PC pathway. (Blood. 2000;96:3719-3724)

Replacement therapy with protein C concentrate in infants and adolescents with meningococcal sepsis and purpura fulminans

We report the effects of substitution with a virus-inactivated protein C (PC) concentrate in disseminated intravascular coagulation (DIC) in infants and children with meningococcal sepsis associated with purpura fulminans. It was a prospective open-label study. Eight pediatric and adolescent patients age 0.2 to 18.25 years with DIC associated with severe acquired PC deficiency (range 0.02 to 0.48 IU/mL; median, 0.22 IU/mL) in meningococcal septic shock and purpura fulminans were studied. Replacement therapy was initiated with a virus-inactivated PC concentrate with an initial intravenous bolus of 80 to 120 IU/kg followed by 50 IU/kg up to six times per day as an adjunctive therapeutic regimen to otherwise optimal intensive care treatment. After initial PC administration, plasma PC levels rose to normal ranges and were maintained under PC replacement therapy. Improving or even normalizing global hemostatic parameters were assessed in all patients. Markedly elevated plasminogen activator inhibitor type 1 (PAI-1) levels prior to treatment, reflecting a reduced fibrinolytic potential, decreased rapidly under PC substitution. Concomitantly improving signs of purpura fulminans reflected by decreasing size of skin lesions, demonstrated a restoring microcirculation. Six of the eight patients survived. One patient required limb amputation; two patients died because of multiorgan failure. Both presented with a severely low plasma PC activity of 0.02 IU/mL on admission to the hospital. No adverse effects were observed with the PC concentrate administration. It can be concluded that the administration of PC concentrate had a marked benefit on the deranged coagulation status of patients with purpura fulminans and meningococcal septicemia. Normalization or even partial correction of hemostasis as well as improvement of microcirculation accompanied by improving signs of purpura fulminans were demonstrated in all patients.

Long-term management of homozygous protein C deficiency: replacement therapy with subcutaneous purified protein C concentrate

We present the case of a full-term newborn in whom purpura fulminans developed shortly after birth. A diagnosis of homozygous protein C deficiency was established based upon undetectable plasma protein C activity and antigenemia in the newborn infant, and was later confirmed by protein C gene analysis. Specific replacement therapy with intravenous protein C concentrate was started 9 days after birth. This rapidly led to the complete regression of cutaneous lesions and consumption coagulopathy. After stabilization, oral anticoagulation was initiated in association with prophylactic treatment with intravenous protein C concentrate. However, oral anticoagulation was finally abandoned as the patient presented several thrombotic and hemorrhagic episodes clearly related to difficulties with anticoagulation. Due to the hazards related to prolonged venous access, we are currently using subcutaneous infusion of protein C concentrate for the long-term management of this condition, with satisfactory results.

Ophthalmic manifestation of congenital protein C deficiency

Under normal conditions activated protein C is a natural anticoagulant that cleaves 2 activated coagulation factors, factor Va and factor VIIIa, thereby inhibiting the conversion of factor X to factor Xa and of prothrombin to thrombin. Additionally, activated protein C enhances tissue-plasminogen activator-mediated fibrinolysis by inhibition of plasminogen activator inhibitor-1. This results in an increase in circulatory plasminogen activator levels. Protein C deficiency, a genetic or acquired thrombophilic abnormality, has been demonstrated to predispose to episodes of potentially blinding and lethal thromboembolic events. Heterozygous-deficient subjects usually remain asymptomatic until adolescence or adulthood. In homozygous-deficient patients, protein C activity is usually less than 1% (reference range, 70%-140%), resulting in thromboembolism as early as in the neonatal period. The major clinical symptoms in affected newborn infants have been purpura fulminans, vitreous hemorrhage, and central nervous system thrombosis. The age of onset of the first symptoms has ranged from a few hours to 2 weeks after birth, usually after an uncomplicated full-term pregnancy and delivery. In contrast to the genetic form, acquired neonatal protein C deficiency occurs particularly in ill preterm babies. Typical complications of prematurity such as respiratory distress syndrome, necrotizing enterocolitis, and neonatal sepsis may also be present. In the medical literature, there are only a few reports of homozygous protein C deficiency in neonates. We present 2 cases of homozygous protein C deficiency with ocular and extraocular manifestation.

[Antithrombin deficiency and thrombosis in a young child]

BACKGROUND

Thromboses represent a rare event in children and may be due to a deficiency of antithrombin.

CASE REPORT

A 10-year-old boy developed thrombosis due to a congenital quantitative deficiency in antithrombin, confirmed by molecular biology. His father was diagnosed with the same deficiency. The child was first treated with heparin and is now on antivitamin K. He is well 26 months after diagnosis.

CONCLUSION

When a young patient presents with a thrombotic event, a congenital deficiency in one of the inhibitors of coagulation, one of which is antithrombin, should be looked for and the condition treated as soon as possible.

Evaluation of protein C and protein S levels during oral anticoagulant therapy

A number of workers have examined protein C in relation to other vitamin K dependent factors during warfarin therapy and successfully identified protein C deficient patients by ratio calculation. However, protein S deficiency has not been addressed in this manner. This study compares protein C and protein S by functional and antigenic determination with procoagulant factors of similar half life (Factors VII and II) in an attempt to identify protein C and protein S deficient patients whilst on oral anticoagulant therapy. Procoagulant and anticoagulant factors were compared by linear regression in a population of normal blood donors and patients on stabilized warfarin therapy to obtain expected values for protein C and protein S dependent upon FVII and FII levels, respectively. Observed over expected values for protein C and protein S were calculated for individual patients and normal ranges derived. Comparison of similarly calculated observed over expected protein C and protein S ratios with these normal ranges successfully identified known protein C and protein S deficient patients who were taking warfarin at time of testing.