Combined heterozygous plasminogen deficiency and factor V Leiden defect in the same kindred

A prediction model for successful anticoagulation in cirrhotic portal vein thrombosis

BACKGROUND AND OBJECTIVE

Portal vein thrombosis (PVT) is a common complication in cirrhosis, and when complete, it increases morbidity and mortality in liver transplant candidates. The aim of the study was to assess the hemostatic status, as well as clinical characteristics of thrombus and patients, as predictors of therapeutic efficacy of anticoagulation for the treatment of PVT in cirrhotics.

PATIENTS AND METHODS

Patients with cirrhosis consecutively treated for PVT with enoxaparin were enrolled. All patients underwent evaluation of coagulation status and thrombophilia screening. Thrombus characteristics and extension were evaluated at baseline and during follow-up. Anticoagulation was continued until recanalization or up to 12 months. Variables correlated with the response to anticoagulation were used to create a predictive score that was validated in an external multicenter cohort.

RESULTS

A total of 65 patients were included and had partial PVT in most cases (72%). Treatment with enoxaparin resulted in an overall response rate of 66% (43/65) after a median time of 4.4 months and 76% (33/43) within the first 6 months. At multivariate analysis, efficacy of anticoagulation correlated with the severity of liver disease, complete verus partial PVT, age of the thrombus, and time interval from treatment start (<6 months). The areas under the curve of the statistical model for predicting the response to anticoagulation were 0.84 and 0.76 for the training (n=65) and validation (n=60) cohorts, respectively.

CONCLUSION

Early diagnosis and early treatment are key factors for the successful management of PVT in cirrhosis, so that screening of PVT and prompt start of anticoagulant treatment should be mandatory.

LPA Variants Are Associated With Residual Cardiovascular Risk in Patients Receiving Statins

BACKGROUND

Coronary heart disease (CHD) is a leading cause of death globally. Although therapy with statins decreases circulating levels of low-density lipoprotein cholesterol and the incidence of CHD, additional events occur despite statin therapy in some individuals. The genetic determinants of this residual cardiovascular risk remain unknown.

METHODS

We performed a 2-stage genome-wide association study of CHD events during statin therapy. We first identified 3099 cases who experienced CHD events (defined as acute myocardial infarction or the need for coronary revascularization) during statin therapy and 7681 controls without CHD events during comparable intensity and duration of statin therapy from 4 sites in the Electronic Medical Records and Genomics Network. We then sought replication of candidate variants in another 160 cases and 1112 controls from a fifth Electronic Medical Records and Genomics site, which joined the network after the initial genome-wide association study. Finally, we performed a phenome-wide association study for other traits linked to the most significant locus.

RESULTS

The meta-analysis identified 7 single nucleotide polymorphisms at a genome-wide level of significance within the LPA/PLG locus associated with CHD events on statin treatment. The most significant association was for an intronic single nucleotide polymorphism within LPA/PLG (rs10455872; minor allele frequency, 0.069; odds ratio, 1.58; 95% confidence interval, 1.35-1.86; P=2.6×10-10). In the replication cohort, rs10455872 was also associated with CHD events (odds ratio, 1.71; 95% confidence interval, 1.14-2.57; P=0.009). The association of this single nucleotide polymorphism with CHD events was independent of statin-induced change in low-density lipoprotein cholesterol (odds ratio, 1.62; 95% confidence interval, 1.17-2.24; P=0.004) and persisted in individuals with low-density lipoprotein cholesterol ≤70 mg/dL (odds ratio, 2.43; 95% confidence interval, 1.18-4.75; P=0.015). A phenome-wide association study supported the effect of this region on coronary heart disease and did not identify noncardiovascular phenotypes.

CONCLUSIONS

Genetic variations at the LPA locus are associated with CHD events during statin therapy independently of the extent of low-density lipoprotein cholesterol lowering. This finding provides support for exploring strategies targeting circulating concentrations of lipoprotein(a) to reduce CHD events in patients receiving statins.

[Polymorphism of the plasminogen activator inhibitor type 1 gene, plasminogen level and thrombosis in patients with antiphospholipid syndrome]

The frequency of venous and arterial thromboses and plasminogen level were investigated in 78 patients with antiphospholipid syndrome (APS), 35 of whom with systemic lupus erythematosus (SLE+APS) and 43 - with primary APS (PAPS). The levels and genotype of plasminogen activator inhibitor type 1 (PAI-1) were determined in 45 patients with APS, of whom 21 patients with SLE + APS and 24 patients with PAPS. A control group included 10 healthy individuals without autoimmune disease signs and thromboses on period of investigation and in past history. It was shown for the first time that for one third of 67 patients with APS and thromboses high positive levels of antiphospholipid antibodies (aPL) are associated with low plasminogen levels. The levels of PAI-1 antigen measured by ELIZA method, which detects active, latent and bound with plasminogen activator PAI-1, were opposed with frequency of thromboses in APS patients. Correlation between the high and increased levels of PAI-1 and high positive aPL levels was found for one third of 43 patients with APS and thrombosis. One of the possible mechanisms of this interconnection was considered. It was shown that arterial and, to a more extent, venous thromboses are associated with the 4G/5G polymorphism of PAI-1 gene and high plasma level of the inhibitor in 79% of APS patients. At the presence of the 4G allele patients with SLE+APS had higher PAI-1 levels than patients with PAPS. The obtained results show that measuring the levels of plasminogen and PAI-1 as well as the 4G/5G polymorphism of PAI-1 gene which is associated with thromboses may have the practical significance for identification of high risk of thrombosis in APS patients.

Increased anticoagulant response to low-molecular-weight heparin in plasma from patients with advanced cirrhosis

INTRODUCTION

Cirrhotic patients may present thrombotic complications that warrant anticoagulant therapy. However, the efficacy of low-molecular-weight heparin (LMWH) in this clinical setting is still unclear.

AIMS/METHODS

To evaluate the in vitro effect of LMWH on thrombin generation (TG) in cirrhotic patients at different stages of liver disease. Thirty cirrhotics (10 Child Pugh A, 10 Child Pugh B and 10 Child Pugh C), 10 subjects with inherited type 1 antithrombin (AT) defect and 10 healthy controls were studied. TG was determined at baseline and with anti-Xa levels after the addition of enoxaparin at 0.35 and 0.7 U anti-Xa mL. The endogenous thrombin potential (ETP) ratio at 0.35 and 0.7 U anti-Xa mL was obtained by dividing ETP with LMWH by ETP at baseline.

RESULTS

Mean AT levels in all cirrhotic subgroups and in patients with AT deficiency were significantly lower than in controls. The 0.35 ETP ratio was significantly lower in cirrhotic patients than in controls (0.26 ± 0.1 vs. 0.48 ± 0.1, P < 0.001) and the reduction paralleled the severity of liver disease, in spite of the concomitant decrease in AT and anti-Xa activity. AT-deficient subjects showed a significantly increased 0.35 ETP ratio compared with both cirrhotic patients and controls (0.69 ± 1 vs. 0.26 ± 0.1, P < 0.001, and vs. 0.48 ± 0.1, P = 0.04 respectively). LMWH at 0.7 U anti-Xa mL completely inhibited TG in 9/30 cirrhosis patients with more advanced liver disease (Child Pugh B and C), whereas complete TG abolition was seen in only 1/10 controls.

CONCLUSIONS

Cirrhotic patients show an increased response to LMWH, which correlates with the severity of liver disease, in spite of reduced AT and anti-Xa activity levels. Thrombin generation may be a useful tool to monitor the response to LMWH in cirrhotic patients.

Plasminogen deficiency

Plasminogen deficiency has emerged as a well-recognized disorder in which reduced levels of plasminogen lead to the development of pseudo membranes on mucosal surfaces, with subsequent end-organ damage of the affected tissue. Ligneous conjunctivitis is the most recognizable, well-documented, and common presentation of the clinical syndromes associated with plasminogen deficiency, although numerous other organs have been reported to be affected. Interestingly, while plasminogen deficiency was initially believed to be related to development of venous thromboembolic disease, more recent data suggest that decreased plasminogen levels may not, in and of themselves, increase the risk of thrombosis. Two types of plasminogen deficiency have been described in the literature. Type I represents a quantitative deficiency and type II a qualitative deficiency. It appears that hypoplasminogenaemia (type I deficiency) is the type most associated with pseudomembrane disease. A variety of genetic mutations has been identified recently and is reported to lead to these disorders. These defects have been identified in diverse populations, with no specific ethnic predilection. However, this disorder may have increased prevalence in areas and communities where consanguinity is more common. Despite the fact that the characteristic lesions are now better recognized and plasminogen levels are accurately and easily measured, adequate treatment of the clinical manifestations of this disorder is lacking. For ligneous conjunctivitis, a plasminogen concentrate formulated into an ophthalmologic preparation has been found to be an effective local therapy. Unfortunately, no plasminogen concentrate is currently available commercially for either systemic or local therapy.

Plasminogen and tissue-type plasminogen activator deficiency as risk factors for thromboembolic disease

OBJECTIVE

To review the published evidence for an association between a deficiency of plasminogen or tissue-type plasminogen activator (tPA) and the risk of thrombosis.

DATA SOURCES

Review of the medical literature, with an emphasis on the last 10 years.

DATA EXTRACTION AND SYNTHESIS

After an initial assessment of the literature, including review of clinical study design and laboratory methods, a draft manuscript summarizing the findings was prepared and circulated to participants in the College of American Pathologists Conference on Diagnostic Issues in Thrombophilia. The key findings and each recommendation were presented for discussion at the conference. Recommendations were accepted if a consensus of the 27 experts attending the conference was reached. The results of the discussion were used to revise the manuscript into its final form.

CONCLUSIONS

The consensus of the conference was that routine laboratory assessment of plasminogen and tPA concentration in patients with thrombophilia is not warranted at this time. Analysis of plasminogen and tPA gene alterations in patients with thrombophilia is also not warranted at this time. Determination of plasminogen concentration should be performed in patients suspected of having ligneous conjunctivitis.

Effect of delivery modalities on the physiologic inhibition system of coagulation of the neonate

The perinatal period is associated with an increased incidence of thromboembolic complications, which may occur in both the maternal and fetal circulation in otherwise normal and healthy adults and fetuses, and this may be related to the activation of the coagulation system at the time of parturition. The risk of these complications is generally much higher in neonates, who have decreased activity of the physiologic inhibition system of coagulation (PISC), including protein C, protein S and antithrombin, in comparison with adults. Therefore, any additional obstetric iatrogenic factors could predispose the neonate to an increased risk of thromboembolic complications. The aim of this study was to evaluate the influence of modality of delivery (spontaneous vaginal delivery vs. elective caesarian section) on the neonatal PISC factor (protein C, protein S and antithrombin) levels and the fibrinolytic system (plasminogen and fibrinogen levels). We studied 41 consecutive healthy newborns, 18 delivered vaginally (mean gestational age 39.7 +/- 0.8) and 23 by elective caesarian section (mean gestational age 38.5 +/- 0.7). Plasma samples were collected from the umbilical cord at birth. AT activity, protein C antigen and activity, total and free protein S antigen, fibrinogen concentration and plasminogen activity were tested. Among PISC factors studied in cord blood of infants born after vaginal delivery, protein C antigen levels and antithrombin activity were statistically higher (41.3 +/- 9.4 vs. 33.9 +/- 7.2 and 58.5 +/- 10.0 vs. 48.4 +/- 12.7, respectively; P<.01), while free protein S was significantly lower (36.8 +/- 11.6 vs. 46.4 +/- 12.5; P<.05) than in newborns delivered by caesarian section. Cord blood plasminogen and fibrinogen were elevated in vaginally delivered neonates in comparison to those delivered by caesarian section, but the difference was not statistically significant. Our data show that the labor stress of vaginal delivery may play a role in influencing the levels of some PISC factors in the cord blood of full-term neonates. In newborns with coagulation disorders, separate reference ranges in coagulation screening tests should be possibly needed depending on the delivery modality.

Symptomatic combined homozygous factor XII deficiency and heterozygous factor V Leiden. luscaber@tin.it

A family with a combined deficiency of factor XII and factor V Leiden is presented. The proposita is a 72-year-old who showed a mild to moderate thrombotic tendency characterized by two episodes of deep venous thrombosis and superficial phlebitis between the age of 50 and 71. She was shown to be carrier of homozygous factor XII deficiency and heterozygous FV Leiden mutation. A sister of the proposita showed the same pattern but remained asymptomatic. Other family members showed either isolated heterozygous factor XII deficiency or combined heterozygous factor XII deficiency and heterozygous FV Leiden mutation but were all asymptomatic. These data lend support to those who maintain that FV Leiden is a mild genetic determinant for thrombosis. The role of FXII deficiency as an additional risk factor remains questionable.