Thrombin generation measured as thrombin-antithrombin complexes predicts clinical outcomes in patients with cirrhosis

AIM

Hypercoagulability has been detected in patients with cirrhosis yet its clinical significance remains unclear. We investigated the association of hypercoagulability with clinical outcomes in patients with cirrhosis.

METHODS

Thrombin-antithrombin (TAT) complexes as thrombin generation (TG) marker, D-dimer, antithrombin (AT), protein C, protein S, international normalized ratio (INR), activated partial thromboplastin time, fibrinogen, Child-Pugh class and Model for End-Stage Liver Disease (MELD) were evaluated. Two different multivariate analyses were performed: one not including MELD (model 1) and one including MELD and excluding INR (model 2).

RESULTS

Eighty-one patients (Child-Pugh class A/B/C: 27/27/27) and 40 healthy subjects were enrolled. Only ΤΑΤ and AT were independently associated with increasing liver disease severity. Increased TAT levels and MELD score were significantly associated with ascites and varices at baseline. Independent predictors of follow-up events were: TAT and MELD score for new-onset ascites; TAT and AT for variceal bleeding (VB); TAT and AT for portal vein thrombosis (PVT); and TAT and MELD for mortality. TAT equaled MELD in mortality prediction at 12 and 18 months. TAT cut-offs at 5.35, 14.6, 13.5 and 9.25 ng/mL identified patient groups with significantly higher probability of new-onset ascites, VB, PVT and mortality, respectively.

CONCLUSION

Increased TG is strongly correlated with portal hypertension-related complications, PVT and mortality in patients with cirrhosis. Measuring TG by TAT could enable risk stratification and institution of preventive strategies to improve clinical outcomes.

Genetic polymorphisms associated with retinal vein occlusion: a Greek case-control study and meta-analysis

BACKGROUND

The genetic background of retinal vein occlusion (RVO) remains unclear. In the current study, we aimed to replicate polymorphisms related to thrombophilia/hypofibrinolysis in a Greek population and also systematically summarize current evidence available on the topic.

MATERIALS AND METHODS

A total of 48 RVO patients and 53 controls were genotyped for factor V H1299R and V Leiden, β-fibrinogen G455A, PAI-1 4G/5G, ACE I/D, HPA1, prothrombin G20210A, factor XIII Val34Leu, MTHFR A1298C and C677T polymorphisms. We examined the association between RVO and the above polymorphisms under a per-allele genetic model in a Greek unrelated case/control population. Additionally, searching PubMed up to January 2012, we identified existing evidence on these polymorphisms and performed meta-analyses.

RESULTS

A total of three polymorphisms had nominally significant associations with RVO. These associations pertained to ACE D allele (odds ratio, OR, 2.08 [95% CI, 1.12-3.85], p = 0.02); factor XIII 34Leu allele (OR = 0.41 [95% CI, 0.18-0.95], p = 0.037] and MTHFR 677T variant (OR = 2.20 [95% CI 1.10-4.40], p = 0.026). We performed a meta-analysis on the associations between RVO and PAI-1 (n = 5), factor V Leiden (n = 21), MTHFR C677T (n = 19) and prothrombin G20210A (n = 21). We observed nominally significant associations only for PAI-1 (OR = 1.27 [95% CI, 1.02-1.60, p = 0.036]) (I(2) = 44.7%), and factor V Leiden (OR = 1.40 [95% CI, 1.07-1.84, p = 0.015]) (I(2) = 3.6%) using random effects model.

CONCLUSIONS

Our results suggest that there may be an association between increased risk for RVO and ACE I/D, MTHFR C677T, PAI-1 4G/5G and factor V Leiden polymorphisms, whereas the Val34Leu variant may exert a protective effect.

Prothrombotic state, cardiovascular, and metabolic syndrome risk factors in prepubertal children born large for gestational age

OBJECTIVE

To evaluate metabolic syndrome and cardiovascular disease risk factors in prepubertal children born large for gestational age (LGA) to nondiabetic, nonobese mothers.

RESEARCH DESIGN AND METHODS

At 6-7 years of age, the comparison of various factors was made between 31 LGA and 34 appropriate-for-gestational-age (AGA) children: fibrinogen, antithrombin III, protein C and S, fasting insulin, glucose, homeostasis assessment model of insulin resistance (HOMA-IR) index, adiponectin, leptin, visfatin, IGF-1, IGF-binding protein (IGFBP)-1, IGFBP-3, lipids, and the genetic factors V Leiden G1691A mutation, prothrombin 20210A/G polymorphism, and mutation in the enzyme 5,10-methylenetetrahydrofolate-reductase gene (MTHFR-C677T).

RESULTS

LGA children had higher levels of leptin (P<0.01), fasting insulin (P<0.01), and HOMA-IR (P<0.01), but lower IGFBP-3 (P=0.0001), fibrinogen (P=0.0001), and lipoprotein(a) (P<0.001) than AGA children. Significantly more LGA children were homozygous for the MTHFR-C677T mutation (P=0.0016).

CONCLUSIONS

Being born LGA to nondiabetic, nonobese mothers is associated with diverse effects on cardiometabolic risk factors at prepuberty.

Thrombophilic risk factors in the pathogenesis of non-arteritic anterior ischemic optic neuropathy patients

BACKGROUND

Non-arteritic anterior ischemic optic neuropathy (N-AION) is caused by acute ischemic infarction of the optic nerve head, supplied by the posterior ciliary arteries. Thrombophilia is the tendency/predisposition to vascular thromboses of arteries and veins, and the existence of thrombophilic risk factors leads to blood hypercoagulability and potentially increased risk for thromboses.

OBJECTIVES

To investigate whether there is an association between N-AION and a wide spectrum of thrombophilic risk factors.

PATIENTS AND METHODS

Seventy-seven consecutive cases of confirmed N-AION and 60 age- and sex-matched consecutive controls constituted the study group. Fibrinogen levels, deficiency of proteins C, S, ATIII, lupus anticoagulant, activated protein C resistance, factor V Leiden, factor V H1299R, factor II G20210A, MTHFR C677T, MTHFR A1298C, GPIIIa A1/A2, and ACE I/D polymorphisms were analysed.

RESULTS

Statistical analysis of the plasma proteins in our study demonstrated that the only significant difference was the one concerning protein S levels. In particular, the mean value for N-AION patients was 78.8% +/- 21.2, and for the control group the mean value was 88% +/- 21.2 (p = 0.013). Despite the above-mentioned result, there was not any statistical difference between the two subgroups regarding actual protein S deficiency, as 9/77 (11.7%) patients and 4/60 (6.7%) controls had protein S levels below 60% (p = 0.32). In our study sample, homozygosity for MTHFR C677T polymorphism in the study group as a whole, and the presence of at least one A2 allele of GPIIIa in the subgroup of male patients as compared to healthy male controls, proved to be the most significant thrombophilic risk factors, with odds ratios of 16.78 (95% C.I 0.96-294.42, p = 0.054) and 4.6 (95% C.I 1.52-13.88, p = 0.007) respectively.

CONCLUSION

Screening for these polymorphisms would probably constitute a valuable procedure in N-AION patients, as they may have an important contribution to the pathogenesis of the disease.

Protein Z Plasma Levels are Not Elevated in Patients with Non-Arteritic Anterior Ischemic Optic Neuropathy

Background:

Protein Z is a glycoprotein that acts as a co-factor for the inhibition of activated coagulation factor X. Protein Z circulating in abnormal levels has been associated with increased risk for acute ischemic events. Non-arteritic Anterior Ischemic Optic Neuropathy (N-AION) is caused by acute ischemic infarction of the optic nerve head, supplied by the posterior ciliary arteries.

Objectives:

The aim was to investigate whether there is an association between N-AION and plasma protein Z levels.

Patients and Methods:

Twenty-six cases of confirmed N-AION and fifty-two controls were included in the study group. Protein Z was estimated in thawed citrate plasma on both N-AION cases and controls by an enzyme immunoassay. The imprecision of the estimation was satisfactory (CV = 4, 6%).

Results:

The controls’ protein Z values distributed within a range 340 to 4200 ng/ml (median = 1420, mean = 1673, SD = 1040 ng/ml). Patients’ protein Z values distributed within a range 420 to 3600 ng/ml (median = 1030, mean = 1520, SD = 939 ng/ml). There was no statistical difference between the two distributions (Independent t-test, p=0.529).

Conclusion:

In our study, protein Z levels are not implicated in the pathogenesis of non-arteritic anterior ischemic optic neuropathy (N-AION).

Genetic risk factors associated with thrombosis in children with congenital neurologic disorders

Thromboembolic events during the perinatal period are responsible for irreversible brain damage owing to cerebral hypoxia and neuronal necrosis. We investigated the presence of thrombophilia risk factors in children with congenital neurologic disorders. Nineteen children (9 males and 10 females), aged 1 to 14 years (median 4.5 years), who had presented with symptoms and signs of congenital neurologic disorders were studied. Thirty-five age-matched healthy children recruited from the same geographic area served as controls. Three patients of 19 (15.8%) were carrying the factor V Leiden mutation compared with 2 children among the controls (5.7%). One patient was heterozygous for the prothrombin G20210A variant (5.2%) compared with one child who was heterozygous among the controls. Three patients were homozygous (15.8%) and 11 were heterozygous (57.9%) for the C677T 5,10-methylenetetrahydrofolate reductase gene mutation compared with 4 (11.5%) and 18 (51.4%), respectively, among the controls. Three patients of 19 (15.8%) were carrying more than one mutation. We found 18 mutations in 79% (15/19) of the patients and 25 mutations in 69% (24/35) of the healthy children. Among the individuals carrying the homozygous 677TT 5,10-methylenetetrahydrofolate reductase genotype, we found 7 mutations in 32% (6/19) of the patients and 7 mutations in 20% (7/35) of the healthy children (P > .05). In one patient, lupus anticoagulant and antiphospholipid antibodies of IgG isotype were detected. Reduced activities of protein C, protein S, or antithrombin III were not observed in either the patient or the control group. Although, among our cases, we found some well-known risk factors associated with thrombosis in adults, the pathogenesis of these clinical entities remains obscure.