Levels Of Coagulation Factor VII Research Articles

Development of a Hypercoagulable-Hypofibrinolytic State Early After Spinal Cord Injury

ObjectivesTo determine whether spinal cord injury (SCI) is associated with adverse changes in coagulation and fibrinolytic factors that underlie thrombogenesis and contribute to atherothrombotic events such as myocardial infarctions (MIs) and strokes. DesignCross-sectional study. SettingNeurorehabilitation hospital and general community. ParticipantsThirty young and middle-aged (20-58 years) adults (N=30) were studied: 14 non-injured community dwelling adults. (11M/4F) and 16 with subacute tetraplegic motor complete SCI during initial inpatient rehabilitation (13M/3F; time since injury: 11.8±5.3 wk). InterventionsNot applicable. Main Outcome MeasuresCirculating markers of coagulation [von Willebrand factor (vWf) and factors VII, VIII, and X], the fibrinolytic system [tissue-type plasminogen activator (t-PA), and plasminogen activator inhibitor-1 (PAI-1) antigen and activity], and fibrin formation (D-dimer) were determined by enzyme immunoassay. ResultsThirty young and middle-aged (20-58 years) adults were studied: 14 non-injured (11M/4F) and 16 with subacute tetraplegic motor complete SCI (13M/3F; time since injury: range 4-25 wk). Circulating levels of coagulation factors VII, VIII, and X were significantly higher (∼20%-45%; P<.05) in the adults with SCI than non-injured adults, whereas vWf was similar between groups. Fibrinolytic markers were adversely disrupted with SCI with t-PA antigen, PAI-1 antigen and PAI-1 activity were markedly higher (∼50%-800%; P<.05) in adults with SCI compared with non-injured adults. The molar concentration ratio of active t-PA to PAI-1 was significantly higher (∼350%) in adults with SCI. Concordant with coagulation cascade activation and fibrinolytic system inhibition, D-dimer concentrations were markedly ∼70% higher (P<.05) in adults with SCI compared with non-injured adults. ConclusionsSubacute tetraplegic motor complete SCI is associated with a prothrombotic hemostatic profile. Adverse changes in the coagulation cascade and fibrinolytic system appear to occur early after injury and may contribute to the increased atherothrombotic risk in adults living with SCI.

SAT-344 Venous Thromboembolism Caused by Primary Hyperparathyroidism

Background. Primary hyperparathyroidism (PHPT) is often overlooked as a potential etiology of hypercoagulability and thrombosis. We present a case in which PHPT was the only identifiable risk factor for an episode of venous thromboembolism (VTE). Case. A 64 year old female with no chronic health problems presented to the emergency department for evaluation of dyspnea and right lower extremity pain. Symptoms had steadily increased in severity over approximately one week. The patient denied any long distance travel, sustained immobility, or tobacco use, and she was not taking any prescription or over-the-counter medications. Examination was notable for right distal lower extremity pain to palpation, but no swelling or erythema was observed. Elevated D-dimer (4.00 mg/mL, < 0.50) and hypercalcemia (12.7 mg/dL, 8.8–10.5) were discovered on initial laboratory testing, and an ECG showed sinus tachycardia. CT angiography of the chest revealed extensive, bilateral pulmonary emboli, and lower extremity venous Doppler studies confirmed a right lower extremity deep venous thrombus (DVT). Unequivocally elevated intact parathyroid hormone (PTH) level (235 pg/mL, 12–88) confirmed a diagnosis of PHPT, and an apparent left lower parathyroid adenoma was identified by both Tc99m parathyroid scintigraphy and neck ultrasonography. After hydration, serum calcium remained in the range of 11.5–12.0 mg/dL. The patient was discharged home on the direct factor Xa inhibitor rivaroxaban (Xarelto™) with a plan for six months of anticoagulation before parathyroidectomy. Conclusions. The skeletal, neuromuscular, cardiovascular, and neuropsychiatric manifestations of PHPT are well described, but little is published regarding PHPT and VTE. In a multivariate analysis of participants in the fourth and fifth Tromsø surveys controlled for age, sex, and BMI, simultaneous elevations of PTH and serum calcium were associated with a nearly 80% increased risk of VTE. PHPT has been linked to several changes that predispose to a hypercoagulable state and thrombosis including dehydration, vasoconstriction, increased platelet count and levels of coagulation factors VII and X, elevated tissue plasminogen activator inhibitor-1 and D-dimer levels, and diminished tissue factor pathway inhibitor levels. Unfortunately, risk of VTE is not addressed in series documenting long-term outcomes for patients undergoing parathyroidectomy for management of PHPT. However, in cases of VTE where PHPT is diagnosed, parathyroidectomy should be considered to potentially improve hypercoagulability and reduce the risk of subsequent VTE.

Biomarkers of Hemostatic Dysregulation, Inflammation, and Infection in Patients Diagnosed with Sepsis Associated Coagulopathy

Introduction: Sepsis associated coagulopathy (SAC) is one of the major pathophysiological mechanisms of sepsis and has been shown to greatly increase mortality in septic patients. SAC is characterized by the inappropriate activation of the coagulation cascade, leading to the formation of microthrombi and the potential for multiple organ failure. Additionally, the excessive consumption of platelets and coagulation factors can create a risk of excessive bleeding. SAC is a complex syndrome, involving coagulation factors, inflammatory cytokines, and several other notable factors of varied origin. In this study, our aim was to evaluate the levels of endocan, pentraxin, and procalcitonin in individuals with SAC diagnosed according to the ISTH criteria in comparison to healthy individuals. Endocan is a soluble, circulating proteoglycan that normally binds to LFA-1 and inhibits leukocyte diapedesis. It is produced by vascular endothelial cells as well as the lung and kidney and has been proposed as a marker of endothelial dysfunction and disease severity in patients with sepsis. Endocan may be useful in the evaluation and tracking of SAC as a marker of endothelial damage caused by excessive inflammation and coagulation. Pentraxin (PTX3) is a protein structurally similar to CRP that is produced by several cell types in response to inflammatory signals and is known to be a marker of inflammation in a number of disease processes. In addition to being the precursor of the hormone calcitonin, procalcitonin is produced by a variety of tissues and may correlate with degree of infection and response to treatment in individuals with sepsis. Taken together, endocan, pentraxin, and procalcitonin may be useful in the evaluation and monitoring of SAC as they are representative of endothelial damage, inflammation, and systemic infection, respectively.Materials and Methods: Blood from 50 patients with SAC and 33 normal individuals obtained from a commercial source (George King Biomedical, Overland Park, KS) were evaluated. Levels of pentraxin, procalcitonin, endocan, and coagulation factors VII, IX, and X were measured using commercially available ELISA kits from Stago (Parsippany, NJ), Lunginnov (Lillie, France) and R&D Systems (Minneapolis, MN). All results are compiled as group mean and expressed as average mean + SD. These values are compared with normal and results were computed as percent increase or decrease.Results: The levels of coagulation factors VII and X were found to be reduced in patients with SAC compared to normal individuals (p < 0.05); the level of factor IX was statistically unchanged. The reduction in factor X was relatively modest, less than a 20% reduction compared to normal, while the reduction in factor VII was more marked, with a greater than 40% reduction compared to normal. The levels of pentraxin, proxalcitonin, and endocan were all found to be significantly elevated in blood from SAC patients compared to blood from normal healthy individuals (p < 0.05). All three markers exhibited a greater than 100% average increase when compared to normal.Discussion: These results indicate that endocan, pentraxin, procalcitonin, and factor VII are all candidates for further investigation in the identification of a more comprehensive molecular profile of SAC and in the development of diagnostic or prognostic tests. The significant degree of change observed in each marker from normal provides a baseline for future studies of these markers in SAC patients. Although these factors individually are not specific markers of SAC, each is a marker for a specific system that is dysregulated in SAC; endocan for endothelial damage, pentraxin for inflammation, procalcitonin for infection, and factor VII for coagulation. Taken together, these biomarkers may be useful in the diagnosis and monitoring of SAC. DisclosuresNo relevant conflicts of interest to declare.

The molecular basis of low activity levels of coagulation factor VII: a Brazilian cohort.

Inherited factor VII (FVII) deficiency is the most common among the rare bleeding disorders. It is transmitted as an autosomal recessive inheritance, due to mutations in the FVII gene (F7). Molecular studies of FVII deficiency are rare in non-Caucasian populations. The aim of the study was to evaluate the molecular basis behind low levels of FVII activity (FVII:C) levelsin a cohort of Brazilian patients. A total of 34 patients with low FVII levels were clinically evaluated and submitted to laboratory tests, among these, prothrombin time and FVII:C, with different thromboplastins. All exons and intron/exon boundaries of F7 were amplified and sequenced. A total of 14 genetic alterations were identified, of which six were described previously, c.1091G>A, c.1151C>T, c.-323_-313insCCTATATCCT, c.285G>A, c.525C>T, c.1238G>A and eight (54.0%) and eight were new, c.128G>A, c.252C>T, c.348G>A, c.417G>A, c.426G>A, c.745_747delGTG, c.843G>A and c.805+52C>T. In addition to the mutation c.1091G>A, known as FVII Padua, the mutation c.1151C>T also presented discrepant FVII:C levels when tested with human and rabbit brain thromboplastin. There was no association between phenotype and genotype. Most of the identified genetic alterations found were polymorphisms. Low levels of FVII:C in this population were mostly related to polymorphisms in F7 and associated with a mild clinical phenotype. Mutation c.1151C>T was associated with discrepant levels of FVII:C using different thromboplastins, such as reported with FVII Padua.

Sneddon's syndrome: case report and review of its relationship with antiphospholipid syndrome

The Sneddon's syndrome is a rare disorder characterized by the occurrence of cerebrovascular disease associated with livedo reticularis. The antiphospholipid syndrome is the most frequent type of acquired thrombophilia, defined by the occurrence of thrombosis or pregnancy morbidity in the presence of persistently positive antiphospholipid antibodies. Approximately 80% of Sneddon's syndrome patients have an antiphospholipid antibody marker. These antibodies may play a pathogenetic role in some cases of Sneddon's syndrome, and many authors consider these two syndromes as the same entity. Although clinical features of antiphospholipid syndrome and Sneddon's syndrome may overlap, there is a distinction between clinical and laboratory evidence suggesting that these two entities are different diseases. A recent finding of coagulopathies, including elevated levels of coagulation factor VII, decreased levels of protein S, and activated protein C in Sneddon's syndrome patients suggested a possible biological link between the vasculopathy and a primary coagulopathy. Moreover, the clinical course seems to be progressive in Sneddon's syndrome patients and includes increase of disability and cognitive deterioration, more arterial involvement, and the antiphospholipid syndrome shows a more benign course. Both syndromes share clinical and laboratory features, and whether Sneddon's syndrome represents a spectrum of antiphospholipid syndrome remains unclear. Sneddon's syndrome patients have a worse prognosis and may represent a subgroup of patients who demands more rigorous follow-up. It is important to recognize the Sneddon's syndrome, particularly because stroke episodes may be prevented through appropriate treatment.

The coagulation system of extremely preterm infants: influence of perinatal risk factors on coagulation

Little is known about the influence of preterm delivery and perinatal risk factors on development and expression of the coagulation system in extremely preterm infants. The objective of this study was to determine reference values for the components of the coagulation system at the first day of life in extremely preterm infants. Components of the coagulation system were examined retrospectively in 132 extremely preterm infants. Patients were grouped according to clinical criteria for preterm delivery: group A: maternal indication; group B: uteroplacental dysfunction; group C: systemic inflammation. Levels of coagulation factors VII and X rose with increasing gestational age, whereas fibrinogen and coagulation factors II, V and VIII remained constant. Levels of factors V and VIII were higher than those of vitamin K-dependent factors. If preterm delivery was caused by placental disorder (group B) or chorioamnionitis (group C), levels of factor II, VIII and X were significantly lower, whereas factor V and VII levels did not differ. In group C fibrinogen levels in group C were higher compared with group A. Identification of perinatal risk factors may help to define patients at risk of bleeding disorders.

Two polymorphisms of the FVII gene and their impact on the risk of myocardial infarction in poles under 45 years of age

High levels of coagulation factor VII (FVII) in plasma have been associated with the increased risk of myocardial infarction (MI) in some studies. Both environmental and genetic factors are responsible for different levels of FVII in plasma. In the FVII gene there are two common polymorphisms (-323A1/A2 and IVS7)which are related to the level of FVII. The purpose of this study was to evaluate the influence of these polymorphisms on the risk of acute myocardial infarction in Poles under 45 years of age. We performed a case-control study of 266 patients with the history of MI. All patients had the first incidence of MI before 45 years of age. The control group consisted of 137 healthy individuals older than 45 years. Carriers of the A2 allele (-32341/A2 polymorphism) have a lower risk of MI than noncarriers (OR = 0.40, 95% CI = 0.20 to 0.80). The IVS7 polymorphism was shown not to be related to MI in this study. Our findings suggest that the -323A1/A2 polymorphism of the FVII gene is related to the risk of MI in Polish individuals. We pointed that plasma cholesterol (OR = 1.11, 95% CI = 1.03 to 1.18), arterial hypertension (OR = 3.84, 95% CI = 1.99 to 7.43) and family history (OR = 2.72, 95% CI = 1.57 to 4.73) are significant predictors of acute myocardial infarction.

Novel Associations of Multiple Genetic Loci With Plasma Levels of Factor VII, Factor VIII, and von Willebrand Factor

Background— Plasma levels of coagulation factors VII (FVII), VIII (FVIII), and von Willebrand factor (vWF) influence risk of hemorrhage and thrombosis. We conducted genome-wide association studies to identify new loci associated with plasma levels. Methods and Results— The setting of the study included 5 community-based studies for discovery comprising 23 608 European-ancestry participants: Atherosclerosis Risk In Communities Study, Cardiovascular Health Study, British 1958 Birth Cohort, Framingham Heart Study, and Rotterdam Study. All subjects had genome-wide single-nucleotide polymorphism (SNP) scans and at least 1 phenotype measured: FVII activity/antigen, FVIII activity, and vWF antigen. Each study used its genotype data to impute to HapMap SNPs and independently conducted association analyses of hemostasis measures using an additive genetic model. Study findings were combined by meta-analysis. Replication was conducted in 7604 participants not in the discovery cohort. For FVII, 305 SNPs exceeded the genome-wide significance threshold of 5.0×10 −8 and comprised 5 loci on 5 chromosomes: 2p23 (smallest P value 6.2×10 −24 ), 4q25 (3.6×10 −12 ), 11q12 (2.0×10 −10 ), 13q34 (9.0×10 −259 ), and 20q11.2 (5.7×10 −37 ). Loci were within or near genes, including 4 new candidate genes and F7 (13q34). For vWF, 400 SNPs exceeded the threshold and marked 8 loci on 6 chromosomes: 6q24 (1.2×10 −22 ), 8p21 (1.3×10 −16 ), 9q34 (&lt;5.0×10 −324 ), 12p13 (1.7×10 −32 ), 12q23 (7.3×10 −10 ), 12q24.3 (3.8×10 −11 ), 14q32 (2.3×10 −10 ), and 19p13.2 (1.3×10 −9 ). All loci were within genes, including 6 new candidate genes, as well as ABO (9q34) and VWF (12p13). For FVIII, 5 loci were identified and overlapped vWF findings. Nine of the 10 new findings were replicated. Conclusions— New genetic associations were discovered outside previously known biological pathways and may point to novel prevention and treatment targets of hemostasis disorders.

The coagulation factor VII gene polymorphisms in patients with myocardial infarction in Ningxia Hui and Han populations

To investigate the characteristics for activated coagulation factor VII(F VIIa) and the R353Q, -323 0/10 bp, HVR4 polymorphisms in the gene in patients with coronary heart disease (CHD) and myocardial infarction from Ningxia Hui and Han populations. Four hundred and twenty angiographically proven CHD patients in the Hui population, and 508 healthy blood donors were tested for their plasma levels of coagulation factor VII using recombinant tissue factor method. The coagulation factor VII gene R353Q, -323 0/10 bp and HVR4 genotypes were identified by polymerase chain reaction. In addition, 600 Han patients with CHD and 604 healthy Han control subjects were also investigated. (1) The plasma F VIIa levels was significantly higher in patients with CHD and myocardial infarction than that in healthy control subjects and angor pectoris (P<0.01) in both Hui and Han populations. (2) There were significant differences in the distribution of genotypes and allelic frequencies of the R353Q between myocardial infarction and angor pectoris disease in the Hui population (P<0.05). So was the -323 0/10 bp locus in both the Hui and Han population. (3) The F VIIa level was significantly higher in individuals with RR genotype than those of Q allele carriers in the Hui population. There are polymorphisms of the F VII gene R353Q, -323 0/10 bp and HVR4 in the Hui and Han populations. The Q allele might be a protective factor against myocardial infarction in the Hui, and the plasma F VIIa level may be influenced by the R353Q polymorphism of the F VII gene. The 10 allele may be a protective factor against myocardial infarction in both the Hui and Han populations.

Segmentation, Reconstruction, and Analysis of Blood Thrombus Formation in 3D 2-Photon Microscopy Images

We study the problem of segmenting, reconstructing, and analyzing the structure growth of thrombi (clots) in blood vessels in vivo based on 2-photon microscopic image data. First, we develop an algorithm for segmenting clots in 3D microscopic images based on density-based clustering and methods for dealing with imaging artifacts. Next, we apply the union-of-balls (or alpha-shape) algorithm to reconstruct the boundary of clots in 3D. Finally, we perform experimental studies and analysis on the reconstructed clots and obtain quantitative data of thrombus growth and structures. We conduct experiments on laser-induced injuries in vessels of two types of mice (the wild type and the type with low levels of coagulation factor VII) and analyze and compare the developing clot structures based on their reconstructed clots from image data. The results we obtain are of biomedical significance. Our quantitative analysis of the clot composition leads to better understanding of the thrombus development, and is valuable to the modeling and verification of computational simulation of thrombogenesis.

Lumbosacral plexopathy associated with aortoiliac occlusive disease

Lumbosacral plexopathy associated with aortoiliac occlusive disease

Association of depressive symptoms with coagulation factors in young healthy individuals

Background Depression has been reported to be an independent risk factor for coronary heart disease (CHD). We investigated the association of depressive symptoms with lipids and coagulation factors in young individuals free of CHD. Methods We recruited 1073 young healthy individuals candidates for military academies (mean age = 18.4 ± 0.8 years, males 762) in whom the presence of depressive symptoms was assessed by using the depression scale of Minnesota Multiphasic Personality Inventory test. Total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, lipoprotein (a), fibrinogen, factors VII, VIII and X were measured. Results The depression score ranged from 22 to 90. The participants were divided into quartiles according to the depression score. Three hundred twenty-two subjects were classified in the upper quartile (score > 48) and 269 in the lower quartile (score < 37) of the depression score. Factor VII (102.95 ± 24 versus 98.5 ± 20%) and X levels (92 ± 11 versus 89.7 ± 10%) were significantly higher in individuals in the upper quartile compared to the lower quartile of the depression score. In a logistic regression model with factor VII as dependent variable (upper versus lower quartile) and depression score, age, gender, body mass index, exercise and smoking as predictor variables, depression was an independent predictor of factor VII levels with an adjusted odds ratio for high levels of factor VII of 1.05 (95% confidence interval 1.008–1.09, p = 0.01). Factor VII levels were associated with triglycerides ( r = 0.21, p = 0.001) while factor X with triglycerides ( r = 0.22, p < 0.001) and cholesterol levels ( r = 0.12, p < 0.001). Conclusions Depressed mood is associated with a hypercoagulant profile as it is expressed by the higher levels of coagulation factors VII and X. This might partially explain the higher propensity for CHD of people with depressive symptoms.

Generation of genetically-altered mice producing very low levels of coagulation factor VII

It has been shown earlier that mice with a total targeted deletion of the factorVII gene (FVII(-/-)) die perinatally, thereby precluding study of adult animals with this total deficiency. Consequently, mice producing very low levels of FVII were developed by targeted replacement of the wild-type (WT) murine FYII gene with its corresponding cDNA, under control of the tetracycline transactivator (tTA) promoter. When backcrossed into the C57BI/6 strain, unchallenged mice containing two replaced FVII(tTA) alleles (FVII(tTA/tTA) produce approximately 0.7% of WT FVII levels, but yet live to adulthood despite displaying severely downregulated overall thrombin production and spontaneously developing cardiac fibrosis at a young adult age. This genetically-altered mouse line provides an excellent animal model to study consequences of a severe FVII deficiency in unchallenged mice and in mice subjected to a variety of experimental challenges.

Nitric oxide and TGF-β1 inhibit HNF-4α function in HEPG2 cells

This study analyzes if the profibrogenic factors nitric oxide and transforming growth factor-β1 (TGF-β1) affect hepatocyte nuclear factor-4α (HNF-4α) function. For this purpose, HepG2 cells were treated with TGF-β1 or with a nitric oxide donor to determine mRNA levels of coagulation factor VII and HNF-4α. Treatment effect on factor VII gene promoter was assessed by chloramphenicol acetyl-transferase assays in cells transfected with the pFVII-CAT plasmid. HNF-4α binding and protein levels were determined by gel shift assays and Western blot. TGF-β1 and nitric oxide downregulated factor VII mRNA levels by inhibiting its gene promoter activity. This inhibition is caused by a decrease in the DNA binding of HNF-4α. TGF-β1 induces degradation of HNF-4α in the proteasome while nitric oxide provokes nitrosylation of cysteine residues in this factor. TGF-β1 and nitric oxide inhibit HNF-4α activity. These findings may explain the loss of liver functions that occurs during fibrosis progression.

Coagulation factor VII, R353Q polymorphism, and serum choline-containing phospholipids in males at high risk for coronary heart disease

Introduction: Elevated levels of coagulation factor VII (FVII) have been associated with increased risk for myocardial infarction (MI). The R353Q polymorphism of the FVII gene has been shown to modify plasma levels of FVII, and has in some studies also been associated with reduced risk for MI. Objectives: To examine the R353Q polymorphism of the FVII gene and the relation to myocardial infarction (MI), cardiovascular disease (CVD), and diabetes, and furthermore, to elucidate the association between the polymorphism and plasma levels of FVII coagulant activity (FVIIc), FVII antigen (FVIIag), activated FVII (FVIIa), and serum choline-containing phospholipids (PC). Methods: In 560 elderly men characterised as hypercholesterolemic in 1972, we examined the R353Q polymorphism by melting curve analysis after real-time PCR. In a subgroup of 205 individuals, FVIIc, FVIIag, FVIIa, and PC were analysed. Results: There were no significant associations between genotype and the disease states, although we observed a lower number of MI cases among subjects with the Q allele, compared to the RR individuals (14% vs. 19%). FVIIag and FVIIc levels were lower in RQ compared to RR subjects, whereas for FVIIa the opposite was observed ( p<0.001 for all). PC correlated positively with FVIIag ( r=0.24, p<0.001), but negatively with FVIIa ( r=−0.25, p<0.001). No genotype specific interactions were found for the association between FVII and PC. Conclusion: No significant associations between the R353Q polymorphism and MI, CVD, or diabetes were observed, although the polymorphism strongly influenced plasma levels of FVII. Serum PC correlated significantly with FVIIag and inversely with FVIIa, independently of genotype.

Experimental Arterial Thrombosis in Genetically or Diet Induced Hyperlipidemia in Rats

To investigate the relationship among lipids, coagulation and thrombosis in the absence of atherosclerosis, spontaneous or dietary-induced hyperlipidemic (FHL) rats were studied. FHL showed higher levels of coagulation factors VII, IX, X, VIII and XII and a shortening of the occlusion time (OT) of an artificial arterial prosthesis as compared with normolipidemic (FNL) animals. Damage of abdominal aorta of FHL was followed by increased fibrin deposition in the vascular intima as compared to FNL. After 5 months of cholesterol-rich diet FNL showed increased cholesterol, triglycerides and factor II, VII, IX, X, XII levels. A significant shortening of the OT and increased fibrin deposition was also observed. Two-month diet withdrawal restored the initial condition. Warfarin treatment, at a dose decreasing vitamin K-dependent factor to levels found in FNL, prolonged the OT and reduced fibrin deposition, without modifying F XII or changing lipid profile. An increase in the activated form of F VII was observed. In contrast, no difference was found in F VII clearance. High lipid levels favour the process of thrombus formation by increasing the activation of vitamin K-dependent coagulation factors. Low-dose warfarin treatment reverts the prothrombotic effect of hyperlipidemia.

Polymorphisms in the factor VII gene and the risk of myocardial infarction in patients with coronary artery disease.

High plasma levels of coagulation factor VII have been suggested to be predictors of death due to coronary artery disease. Since polymorphisms in the factor VII gene contribute to variations in factor VII levels, such polymorphisms may be associated with the risk of myocardial infarction, which is precipitated by thrombosis. We studied a total of 444 patients, 311 of whom had severe, angiographically documented coronary atherosclerosis. Of these 311 patients, 175 had documentation of a previous myocardial infarction. As a control group, 133 patients with normal coronary arteriograms were also included. We measured the levels of activated factor VII and assessed three polymorphisms in the factor VII gene, one involving the promoter (A1 and A2 alleles), one involving the catalytic region (R353Q), and one involving intron 7. Each of the polymorphisms influenced factor VII levels. Patients with the A2A2 and QQ genotypes had the lowest levels of activated factor VII (66 percent and 72 percent lower, respectively, than the levels in patients with the wild-type genotypes). The frequencies of the various genotypes in the patients free of coronary artery disease were similar to those in the entire population of patients with coronary artery disease. In the latter group, there were significantly more heterozygotes and homozygotes for the A2 and Q alleles among those who had not had a myocardial infarction than among those who had had an infarction (P=0.008 for the presence of the promoter polymorphism and P=0.01 for the presence of the R353Q polymorphism by chi-square analysis). The adjusted odds ratio for myocardial infarction among the patients with the A1A2 or RQ genotype was 0.47 (95 percent confidence interval, 0.27 to 0.81). Our findings suggest that certain factor VII genotypes have a role in protection against myocardial infarction. This may explain why some patients do not have myocardial infarction despite the presence of severe coronary atherosclerosis.

Increased D-dimer Levels in Twin Gestation

In normal pregnancy, the hemostatic balance is displaced toward hypercoagulability. The elevation in plasma levels of coagulation factors VII, VIII, and X and fibrinogen and the increased concentrations of plasminogen activator inhibitors [1,2] may predispose individuals to thromboembolism, especially near term [1,3]. Because human multifetal gestation requires still greater physiological alterations, the imbalance in hemostasis is further exaggerated. It has been suggested that the changes in the coagulation system near term may even mimic low-grade disseminated intravascular coagulopathy [4]. However, for the majority of women with multifetal gestation, the coagulopathy observed in the laboratory is not clinically apparent [5]. Despite the large body of research on the physiological adaptation to pregnancy, relatively little is known of the biological adaptation in general and the hemostatic changes in particular associated with multiple gestation.

Polymorphisms in the coagulation factor VII gene and the risk of myocardial infarction.

High blood levels of coagulation factor VII are associated with a risk of ischemic vascular disease. Although factor VII levels may be genetically determined, the relation between genetic polymorphisms of factor VII, factor VII blood levels, and the risk of myocardial infarction has not been established. We performed a case-control study of 165 patients with familial myocardial infarction (mean [+/-SD] age, 55+/-9 years) and 225 controls without a personal or family history of cardiovascular disease (mean age, 56+/-8 years). The polymorphisms involving R353Q and hypervariable region 4 of the factor VII gene were studied. Factor VII clotting activity and antigen levels were also measured. Patients with the QQ or H7H7 genotype had a decreased risk of myocardial infarction (odds ratios, 0.08 [95 percent confidence interval, 0.01 to 0.9] and 0.22 [95 percent confidence interval, 0.08 to 0.63], respectively). For the R353Q polymorphism, the RR genotype was associated with the highest risk, followed by the RQ genotype and then by the QQ genotype (P<0.001). For the polymorphism involving hypervariable region 4, the combined H7H5 and H6H5 genotypes were associated with the highest risk, followed in descending order by the H6H6, H6H7, and H7H7 genotypes (P<0.001). Patients with the QQ or H7H7 genotype had lower levels of both factor VII antigen and factor VII clotting activity than those with the RR or H6H6 genotype. Patients with the lowest level of factor VII clotting activity had a lower risk of myocardial infarction than those with the highest level (odds ratio, 0.13; 95 percent confidence interval, 0.05 to 0.34). Our findings suggest that certain polymorphisms of the factor VII gene may influence the risk of myocardial infarction. It is possible that this effect may be mediated by alterations in factor VII levels.

Pathologic fibrin formation and cold-induced clotting of membrane oxygenators during cardiopulmonary bypass

In 1,800 patients undergoing cardiac surgery over a 2-year period, 11 incidents of abnormal inlet pressure elevations occurred before the membrane oxygenators. In 3 patients, the oxygenators had to be changed during cardiopulmonary bypass. This complication was found to be caused by fibrin formation possibly secondary to precipitaition of fibrinogen with other coagulation factors in the heat exchangers of the oxygenators during the cooling phase. Large amounts of fibrin were demonstrated in the exchanger of the oxygenators. After careful washing of the apparatus, plasmin was added and fibrin was detected by measuring D-dimer levels. In heat exchangers from uneventful operations, only trace amounts of fibrin were found. Because there were no cold agglutinins demonstrated in the patients before surgery, cryoprecipitation studies were performed soon after surgery. When the patients' plasma samples were studied at different temperatures, from 37°C down to 3°C, cryoprecipitates or a gel (in 1 patient only) were formed. This indicated that there might be something abnormal with regard to fibrinogen-fibrin formation. The study patients were therefore investigated after the acute phase of the operation had ended for various coagulation factors, as well as for fibrin gel network characteristics. The results were compared with those of a control group ( n = 10) with uneventful operations. There were no differences between the groups with regard to levels of coagulation factors VII and VIII and von Willebrand factor, although they were increased in both groups. The mean levels of coagulation inhibitors, antithrombin and Protein S, were slightly lower in the study patients. All of these patients had a highly pathologic, ie, tight fibrin gel network, except for the patient in whose sample a gel formed, despite being treated with aspirin or oral anticoagulants. The network was also tighter in some of the controls ( v middle-aged reference individuals), although it was significantly tighter in the patients. It is concluded that some individuals who have an increased tendency to form tighter fibrin gel networks might be at increased risk for a severe complication during cardiac surgery performed under hypothermia.