G20210A prothrombin gene polymorphism and coronary ischaemic syndromes: a phenotype-specific meta-analysis of 12 034 subjects

Serological short-chain fatty acid and trimethylamine N-oxide microbial metabolite imbalances in young adults with acute myocardial infarction

Acute myocardial infarction (AMI) is associated with systemic inflammatory processes and metabolic alterations. Microbial-derived metabolites, such as short-chain fatty acids and trimethylamine N-oxide (TMAO), have emerged in recent years as key players in the modulation of inflammation, with potential implications for cardiovascular diseases. We performed a prospective observational study that monitored the serological concentration of bacterial metabolites in 45 young patients (<55 years) without cardiovascular risk factors but with AMI, at hospital admission and at 3 months of follow-up, and compared them with a control group. TMAO and acetate levels were significantly higher in AMI, whereas butyrate and propionate were significantly lower. The acetate/propionate ratio showed the most discrimination between AMI and controls by receiver operating characteristic analysis (area under the curve 0.769, P < 0.0001). A multivariate logistic regression model revealed that this ratio was independently associated with AMI. Short-chain fatty acid concentrations, but not TMAO, exhibited significant correlations with inflammatory and coagulation parameters. Three months after the acute AMI event, all metabolite levels returned to those observed in healthy controls except butyrate. In conclusion, our study reveals disturbances of the serological concentration of microbiota-derived metabolites in AMI that are also related to inflammatory and coagulation parameters. These findings highlight an interesting field of study in the potential role of microbial metabolites from gut in cardiovascular disease.

Acute Myocardial Infarction in Patients with Hereditary Thrombophilia-A Focus on Factor V Leiden and Prothrombin G20210A

Factor V (FV) Leiden and prothrombin G20210A are the most common hereditary thrombophilias. While their role in venous thromboembolism is well known, there are still uncertainties regarding their relationship with arterial thrombotic events, especially coronary ones. Our research, based on an in-depth analysis of the available literature, provides up-to-date information on the relationship between FV Leiden and prothrombin G20210A and acute myocardial infarction. FV Leiden and prothrombin G20210A screening should be implemented only in select cases, such as acute coronary syndrome in young individuals and/or in the absence of traditional cardiovascular risk factors and/or in the absence of significant coronary artery stenosis at angiography. Their identification should be followed by the implementation of optimal control of modifiable traditional cardiovascular risk factors to reduce the risk of recurrent events and genotyping and genetic counseling of all family members of affected cases for proper prophylaxis. An extended dual antiplatelet therapy (DAPT) may be considered, given the lower risk of bleeding under DAPT conferred by FV Leiden.

Risk factors profile of young and older patients with myocardial infarction

Myocardial infarction (MI) among young adults (<45 years) represents a considerable proportion of the total heart attack incidents. The underlying pathophysiologic characteristics, atherosclerotic plaque features, and risk factors profile differ between young and older patients with MI. This review article discusses the main differences between the younger and elderly MI patients as well as the different pathogenic mechanisms underlying the development of MI in the younger. Young patients with MI often have eccentric atherosclerotic plaques with inflammatory features but fewer lesions, and are more likely to be smokers, obese, and have poor lifestyle, such as inactivity and alcohol intake. Compared to older MI patients, younger are more likely to be men, have familial-combined hyperlipidaemia and increased levels of lipoprotein-a. In addition, MI in younger patients may be related to use of cannabis, cocaine use, and androgenic anabolic steroids. Genomic differences especially in the pathways of coagulation and lipid metabolism have also been identified between young and older patients with MI. Better understanding of the risk factors and the anatomic and pathophysiologic processes in young adults can improve MI prevention and treatment strategies in this patient group. Awareness could help identify young subjects at increased risk and guide primary prevention strategies. Additional studies focusing on gene pathways related to lipid metabolism, inflammation, and coagulation are needed.

A System-Wide Investigation and Stratification of the Hemostatic Proteome in Premature Myocardial Infarction

Introduction

Advancing understanding of key factors that determine the magnitude of the hemostatic response may facilitate the identification of individuals at risk of generating an occlusive thrombus as a result of an atherothrombotic event such as an acute Myocardial Infarction (MI). While fibrinogen levels are a recognized risk factor for MI, the association of thrombotic risk with other coagulation proteins is inconsistent. This is likely due to the complex balance of pro- and anticoagulant factors in any individual.

Methods

We compared measured levels of pro- and anticoagulant proteins in plasma from 162 patients who suffered an MI at an early age (MI <50 y) and 186 age- and gender-matched healthy controls with no history of CAD. We then used the measurements from these individuals as inputs for an established mathematical model to investigate how small variations in hemostatic factors affect the overall amplitude of the hemostatic response and to identify differential key drivers of the hemostatic response in male and female patients and controls.

Results

Plasma from the MI patients contained significantly higher levels of Tissue Factor (P = 0.007), the components of the tenase (FIX and FVIII; P < 0.0001 for both) and the prothrombinase complexes (FX; P = 0.003), and lower levels of Tissue Factor Pathway Inhibitor (TFPI; P = 0.033) than controls. The mathematical model, which generates time-dependent predictions describing the depletion, activation, and interaction of the main procoagulant factors and inhibitors, identified different patterns of hemostatic response between MI patients and controls, and additionally, between males and females. Whereas, in males, TF, FVIII, FIX, and the inhibitor TFPI contribute to the differences seen between case and controls, and in females, FII, FVIII, and FIX had the greatest influence on the generation of thrombin. We additionally show that further donor stratification may be possible according to the predicted donor response to anticoagulant therapy.

Conclusions

We suggest that modeling could be of value in enhancing our prediction of risk of premature MI, recurrent risk, and therapeutic efficacy.

Biochemical risk factors of atherosclerotic cardiovascular disease: from a narrow and controversial approach to an integral approach and precision medicine

INTRODUCTION

Guidelines of management of dyslipidemias and prevention of cardiovascular disease (CVD) are based on firm scientific evidence obtained by randomized controlled trials (RCTs). However, the role of elevated low-density lipoprotein-cholesterol (LDL-C)as a risk factor of CVD and therapies to lower LDL-C are frequently disputed by colleagues who disagree with the conclusions of the RCTs published. This review focuses on this dispute, and evaluates the current approach of management of dyslipidemias and CVD prevention to find modern alternatives for more precise diagnosis and therapy of dyslipidemic patients.

AREAS COVERED

Recent interest in lipoprotein(a) (Lp(a)) and remnants lipoproteins and in therapies that do not influence LDL-C levels primarily, such as anti-inflammatory drugs and icosapent ethyl, has revitalized our concern to optimize the care for patients with increased CVD risk without focusing simply on reduction of LDL-C by therapy with statins, ezitemibe, and proprotein convertase subtilisin-kexin type 9 (PCSK9) inhibitors.

EXPERT OPINION

The limited characterization of study populations by measurement of total cholesterol (TC), high-density lipoprotein-cholesterol (HDL-C) and triglycerides (TG) followed by measurement or calculation of LDL-C should be extended by a more integral approach in order to realize precision diagnostics and precision medicine, for the sake of personalized patient care.

Family history in first degree relatives of patients with premature cardiovascular disease

BACKGROUND

Family history (FH) of cardiovascular disease (CVD) in first degree relatives (FDR) is a major risk factor, especially for premature events. Data are sparse on FH of different manifestations of CVD among FDRs of patients with premature myocardial infarction (MI), chronic stable angina (CSA) or peripheral vascular disease (PVD).

METHODS

We obtained FHs from first degree relatives (parents or siblings) of 230 consecutive patients with premature (men < 60 and women < 65 years) CVD, including 79 wth MI, 39 CSA, 51 PVD and 61 blood donors. Among 1225 parents or siblings, 421 had MI, 222 CSA, 261PVD and 321 were among blood donors.

RESULTS

FH of MI were 5.6% (18/321) among blood donors, 14.0% (59/421) among patients with premature MI, 14.4% (32/222) CSA, and 8.0% (21/261) PVD. (all p < 0.05). For FH of CSA the corresponding frequencies were 3.7% 5.2%, 11.3%, and 6.9%. (all p < 0.05). For PVD, the corresponding frequencies were 2.1%, 3.4%, 0.9% and 0.7%, respectively. (p = ns).

CONCLUSIONS

These data are compatible with the hypothesis that FH of MI, CSA and PVD are significantly different for patients with premature MI or CSA but not PVD.

[Hemostatic Gene Polymorphisms in Acute Coronary Syndrome with Nonobstructive Coronary Atherosclerosis]

PURPOSE

to study distribution of genes of the coagulation system, unfavorable in relation to the risk of thrombosis, and their influence on serum parameters ofthe hemostasis system in patients with nonobstructive coronary atherosclerosis (NCA) and acute coronary syndrome (ACS).

MATERIALS AND METHODS

We included in this nonrandomized open study patients with ACS older than 18 years with intact coronary arteries or confirmed at coronary angiography stenosis &lt;50%. Genotypes of these patients were analyzed by 8 polymorphic variants of the hemostatic system genes which previously were found to be associated with the thrombophilia risk: F2 (20210 G&gt;A) rs1799963, F5 (1691 G&gt;A) rs6025, F7 (10976G&gt;A) rs6046, F13 (163 G&gt;T) rs5985, F1 (-455G&gt;A) rs1800790, GP Ia - Ila (807C&gt;t) rs1126643, GP Ilb-IIIa (1565 T&gt;C) rs5918, PAI-I (-6755G&gt;4G) rs1799889. Activities of protein C, Von Willebrand factor, plasminogen, and antithrombin III were also determined.

RESULTS

Of 913 patients with ACS in 30 (3.3%) with mean age 54±11 years we detected NCA. Acute myocardial infarction (AMI) was diagnosed in 24 (80%), unstable angina - in 6 (20%) patients. Only in 1 patient we found no carriage of thrombosis associated genotypes. The frequency of occurrence of the heterozygous genotype of the factor V gene was 1 (3%). Heterozygous genotype of the factor XIII was registered significantly more often in patients with present atherosclerotic lesion compared with those with intact coronary arteries. Mean activity of protein C was 103% [90; 110], antithrombin III - 96% [88; 103], Von Willebrand factor - 137% [114; 162], plasminogen - 109% [102; 112]. At admission lowering of antithrombin III and protein C activities was detected in 4 cases (13%). In dynamics level of these parameters was restored. Elevation of Von Willebrand factor activity at admission was detected in 14 cases (14%) and remained elevated one year after the index event. There was no association between of fibrinogen level, protein C activity, rs1800790 and rs6025 gene polymorphisms, respectively. One-year mortality was 7% (n=2). For one year occurred 1 AIM recurrence (3%), heart failure developed in 15 patients (50%), 11 patients (37%) were repetitively hospitalized due to all causes. No association was revealed between activity of studied blood serum markers and 1 -year outcomes (death, re-AIM, rehospitalization).

CONCLUSION

Among ACS patients 3.3% had NCA, what corresponded to the literature data. Carriage of at least 1 polymorphic variant of 8 thrombosis associated genes of the coagulation system was found in 97 % of patients with ACS and NCA. Distribution of these variants was like that in the European population and in patients with AIM at the background of stenosing atherosclerosis. Level of serum markers did not depend on distribution of polymorphic variants of the coagulation system genes, and presence of atherosclerotic coronary artery lesions. There was no association between hospital and long-term outcomes and distribution of polymorphic variants of thrombosis associated coagulation system genes, as well as levels of blood serum markers.

Prothrombin Gene G20210A Variant in Angiographically Documented Patients with Coronary Artery Stenosis

Background: Studies on the association between the prothrombin G20210A variant and coronary artery disease (CAD) risk are inconclusive. This study aimed to investigate the possible association between the G20210A variant in the prothrombin gene and documented CAD and its severity. Methods: This study enrolled 1460 patients who were consecutively admitted for elective coronary angiography. Via the standard angiographic techniques, coronary angiographies were done and the presence and severity of CAD were determined through the clinical vessel score and the Gensini score. Prothrombin G20210A genotypes were identified using PCR-RFLP. Results: This cross-sectional study was performed on 953 men and 507 women at a mean age of 58.21±10.33 years. The median and the interquartile range for the Gensini score were not statistically significantly different between the wild (GG) and mutant (AA+GA) genotypes (P=0.440). The association between the G20210A polymorphism and the severity of CAD with respect to the vessel score also showed no significant linear trend of higher numbers of diseased vessels (P= 0.765 for the Mantel-Haenszel test of linear trend) in the AA+GA genotype as compared with the GG genotype. Conclusion: Our data failed to confirm the hypothesis that the G20210A variant mutation may be a significant determinant of CAD risk or its severity.

[ST elevation myocardial infarction in young adults: Is there an interest for thrombophilia screening?]

BACKGROUND

Coronary lesions characteristics as well as patient thrombogenicity can explain coronary events manifestation. In young patient, local conditions are usually less important and thrombogenicity could play a significant role. Assessing thrombophilia could be justified in young patients and may induce an adapted therapeutic management.

PURPOSE

We aimed to assess the prevalence of thrombophilia and therapeutic modification in young adults aged≤55 years admitted in our department for ST elevation myocardial infarction (STEMI).

METHODS

From January 2013 to January 2017, data on all patients aged≤55 years with STEMI admitted in emergency were retrospectively retrieved from our database. Thrombophilia investigation was made regarding clinical (with or without cardiovascular risk factors [CVRF]), biological and/or angiographic evaluation.

RESULTS

A total of 133 patients aged≤55 years with STEMI were included. Cardiac arrest occurred in 15 patients (11%). One or less CVRF were found in 47 patients (35%). Smoking was reported in 93 patients (70%) and drug addiction (cannabis, cocaine) in 19 patients (14%). A subset of 51 patients (38%) were screened for thrombophilia. Patients with thrombophilia assessment were younger, less active smokers and presented less CVRF than patients without investigation (P<0.001). Single vessel diseased was found in 88 patients (66%). No differences regarding coronary procedural characteristic were found between the two groups. The most frequently encountered aetiology, found in 122 patients (92%), was de novo intra-arterial thrombosis related to atherosclerosis. In patients with thrombophilia assessment (n=51), one or more abnormal biological results was found in 22 patients (43%) and a therapeutic adjustment was made in 6 patients (12%).

CONCLUSION

Thrombophilia screening in young STEMI adults showed an abnormality in 43% of cases. Antithrombotic treatment can be modified after its demonstration.

[Acute coronary syndrome in a young female patient: findings beyond coronary lesions]

Nous exposons le cas d’une patiente de 47 ans qui présente un syndrome coronarien aigu et une probable embolie artérielle du membre inférieur droit dans l’étude duquel nous détectons la présence de la mutation du gène de la prothrombine G201210A associée à la présence de facteur anticoagulant lupique. La patiente a bénéficié d’une transplantation cardiaque avec bonne évolution clinique.

Thrombophilia in 153 Patients With Premature Cardiovascular Disease ≤Age 45

We assessed contributions of thrombophilia to premature cardiovascular disease (CVD) events (≤ age 45) in 153 patients. Test results of thrombophilia-hypofibrinolysis were obtained in 153 patients with CVD ≤ age 45, 110 healthy normal controls, and 110 patients who had venous thromboembolism (VTE) without CVD. Of the 153 patients with CVD, 121 (79%) had sustained myocardial infarction, 70 (46%) had coronary artery stenting, and 53 (35%) had coronary artery bypass grafts. The first CVD events occurred at ages >20 to 35 in 47 patients and at ages >35 to 45 in 106 patients. At study entry, median low-density lipoprotein cholesterol was 126 mg/dL, 56 (37%) smoked, 56 (37%) had hypertension, and 56 (37%) were diabetic. Cases differed from normal controls for high factor VIII (10 [22%] of 45 vs 7 of 103 [7%], P = .007), high homocysteine (32 [21%] of 151 vs 5 [5%] of 107, P = .0002), low free protein S (5 [11%] of 44 vs 2 [2%] of 96, P = .032), high anticardiolipin antibodies (ACLA) IgM (11 [9%] of 129 vs 2 [2%] of 109, P = .024), high lipoprotein (a) [Lp(a)] (46 [30%] of 151 vs 21 [19%] of 110, P = .038), and the lupus anticoagulant (4 [11%] of 37 vs 2 [2%] of 110, P = .035). There were no differences ( P > .05) between cases and VTE controls except free protein S and Lp(a). Free protein S was more often low in VTE controls (24 [28%] of 85 vs 5 [11%] of 44, P = .03) and Lp(a) was more often high in cases (46 [30%] of 151, VTE controls 12 [17%] of 71, P = .032). In 153 patients with premature CVD ≤ age 45, thrombophilia was pervasive (high factor VIII, homocysteine, ACLA IgM, low free protein S, high Lp(a), and lupus anticoagulant), evidencing thrombotic contribution to premature CVD. Moreover, thrombophilia in patients with premature CVD was comparable to VTE controls, emphasizing the pervasive nature of thrombophilia in premature CVD.

Prothrombin G20210A (rs1799963) polymorphism increases myocardial infarction risk in an age-related manner: A systematic review and meta-analysis

G20210A polymorphism (rs1799963) within the prothrombin gene is associated with a higher circulation level of prothrombin, thus increasing the likelihood of developing myocardial infarction (MI). Opinions differ regarding the correlation between prothrombin G20210A genotype and MI risk, which prompted us to conduct a meta-analysis to determine this association. PubMed, EMBASE, Web of Science and CNKI were searched for pertinent reports. A total of 34 studies involving 14 611 MI cases and 84 358 controls were analyzed in this quantitative analysis. We found a statistically significant association between prothrombin G20210A polymorphism and MI in the allele model (A vs. G, OR = 1.43, 95%CI: 1.18–1.72), heterozygote model (GA vs. GG, OR = 1.41, 95%CI: 1.16–1.72) and dominant model (GA + AA vs. GG, OR = 1.41, 95%CI: 1.15–1.72). The association remains significant in Caucasians but not in non-Caucasians. Moreover, prothrombin G20210A polymorphism increases MI risk in an age-related manner. A further significant association was found in a subpopulation younger than 55 years (allele model, OR = 1.76, 95%CI: 1.32–2.35; heterozygote model, OR = 1.70, 95%CI: 1.24–2.33; dominant model, OR = 1.70, 95%CI: 1.24–2.34). Sensitivity analysis and publication bias analysis revealed stable and statistically robust results. Our meta-analysis demonstrated that prothrombin G20210A polymorphism may represent a risk factor for MI.

Association Between the G20210A Polymorphism of Prothrombin Gene and Myocardial Infarction in Tunisian Population

The prothrombin is the precursor of the serine protease thrombin, a key enzyme in homeostasis. Prothrombin G20210A polymorphism (rs1799963) was described as a moderate risk factor for venous thrombosis because this mutation is associated with prothrombin elevated levels which may lead to an imbalance between the procoagulant, anticoagulant, and fibrinolytic system. 20210A carriers have an increased risk of thrombosis. In this study, we proposed to determine the prevalence of 20210A prothrombin variant among Tunisian population, and to evaluate the potential relevance of this variant with myocardial infarction. This study included 1290 unrelated Tunisians (1007 male and 283 female) divided in two groups: Four hundred and eighty-seven MI patients (mean age: 52.64 ± 8.98 years) and 803 apparently healthy controls (mean age: 51 ± 8.99). The prothrombin G20210A polymorphism was carried out by polymerase chain reaction/restriction fragment length polymorphism (PCR-RFLP) analysis. The distribution of genotypes was in accordance with Hardy-Weinberg equilibrium (p > 0.05). A significant difference in genotype distribution and allele frequency was observed between patients and controls. Male patients with MI had a frequency of 97 % for GG genotype and 3 % for GA+AA genotypes. The control group had a frequency of 99 % for the GG genotype and 1 % for the GA+AA genotypes which is significantly lower than the frequency found in patients (p = 0.01). The same genotype frequencies were found in women (p = 0.032). The MI patient group showed a significantly higher frequency of 20210A allele compared to controls 0.02 versus 0.01 [OR = 3.60 (95 % CI = 1.29-10.53), p = 0.005] in men and 0.015 versus 0.068 [OR = 4.68 (95 % CI = 1.60-14.26), p = 0.001] in women. Our work showed a significant but not independent association between the G20210A polymorphism of the prothrombin gene and MI in the Tunisian population.

The impact of blood coagulability on atherosclerosis and cardiovascular disease

Although the link between blood coagulation and atherogenesis has been long postulated, only recently, and through the extensive work on transgenic mice, crossbred on an atherogenic background, has the direction of this interaction become visible. In general, hypercoagulability in mice tends to increase atherosclerosis, whereas hypocoagulability reduces the atherosclerotic burden, depending on the mouse model used. The information on a direct relationship between coagulation and atherosclerosis in humans, however, is not that clear. Almost all coagulation proteins, including tissue factor, are found in atherosclerotic lesions in humans. In addition to producing local fibrin, a matrix for cell growth, serine proteases such as thrombin may be very important in cell signaling processes, acting through the activation of protease-activated receptors (PARs). Activation of PARs on vascular cells drives many complex processes involved in the development and progression of atherosclerosis, including inflammation, angiogenesis, and cell proliferation. Although current imaging techniques do not allow for a detailed analysis of atherosclerotic lesion phenotype, hypercoagulability, defined either by gene defects of coagulation proteins or elevated levels of circulating markers of activated coagulation, has been linked to atherosclerosis-related ischemic arterial disease. New, high-resolution imaging techniques and sensitive markers of activated coagulation are needed in order to study a causal contribution of hypercoagulability to the pathophysiology of atherosclerosis. Novel selective inhibitors of coagulation enzymes potentially have vascular effects, including inhibition of atherogenesis through attenuation of inflammatory pathways. Therefore, we propose that studying the long-term vascular side effects of this novel class of oral anticoagulants should become a clinical research priority.

Thrombotic gene polymorphisms and postoperative outcome after coronary artery bypass graft surgery

Background

Emerging perioperative genomics may influence the direction of risk assessment and surgical strategies in cardiac surgery. The aim of this study was to investigate whether single nucleotide polymorphisms (SNP) affect the clinical presentation and predispose to increased risk for postoperative adverse events in patients undergoing coronary artery bypass grafting surgery (CABG).

Methods

A total of 220 patients undergoing first-time CABG between January 2005 and May 2008 were screened for factor V gene G1691A (FVL), prothrombin/factor II G20210A (PT G20210A), angiotensin I-converting enzyme insertion/deletion (ACE-ins/del) polymorphisms by PCR and Real Time PCR. End points were defined as death, myocardial infarction, stroke, postoperative bleeding, respiratory and renal insufficiency and event-free survival. Patients were compared to assess for any independent association between genotypes for thrombosis and postoperative phenotypes.

Results

Among 220 patients, the prevalence of the heterozygous FVL mutation was 10.9% (n = 24), and 3.6% (n = 8) were heterozygous carriers of the PT G20210A mutation. Genotype distribution of ACE-ins/del was 16.6%, 51.9%, and 31.5% in genotypes I/I, I/D, and D/D, respectively. FVL and PT G20210A mutations were associated with higher prevalence of totally occluded coronary arteries (p < 0.001). Furthermore the risk of left ventricular aneurysm formation was significantly higher in FVL heterozygote group compared to FVL G1691G (p = 0.002). ACE D/D genotype was associated with hypertension (p = 0.004), peripheral vascular disease (p = 0.006), and previous myocardial infarction (p = 0.007).

Conclusions

FVL and PT G20210A genotypes had a higher prevalence of totally occluded vessels potentially as a result of atherothrombotic events. However, none of the genotypes investigated were independently associated with mortality.

Quality of systematic reviews of observational nontherapeutic studies

INTRODUCTION

High-quality epidemiologic research is essential in reducing chronic diseases. We analyzed the quality of systematic reviews of observational nontherapeutic studies.

METHODS

We searched several databases for systematic reviews of observational nontherapeutic studies that examined the prevalence of or risk factors for chronic diseases and were published in core clinical journals from 1966 through June 2008. We analyzed the quality of such reviews by using prespecified criteria and internal quality evaluation of the included studies.

RESULTS

Of the 145 systematic reviews we found, fewer than half met each quality criterion; 49% reported study flow, 27% assessed gray literature, 2% abstracted sponsorship of individual studies, and none abstracted the disclosure of conflict of interest by the authors of individual studies. Planned, formal internal quality evaluation of included studies was reported in 37% of systematic reviews. The journal of publication, topic of review, sponsorship, and conflict of interest were not associated with better quality. Odds of formal internal quality evaluation (odds ratio [OR], 1.10 per year; 95% confidence interval [CI], 1.02-1.19) and either planned, formal internal quality evaluation or abstraction of quality criteria of included studies (OR, 1.17 per year; 95% CI, 1.08-1.26) increased over time, without positive trends in other quality criteria from 1990 through June 2008. Systematic reviews with internal quality evaluation did not meet other quality criteria more often than those that ignored the quality of included studies.

CONCLUSION

Collaborative efforts from investigators and journal editors are needed to improve the quality of systematic reviews.

No early signs of atherosclerotic alterations in carriers of inherited thrombophilia

BACKGROUND

Congenital thrombophilia is a risk factor for venous thromboembolism (VTE). Whether it is associated with increased risk of arterial disease is today a matter of debate. We aimed to look for early signs of atherosclerotic alterations in carriers of inherited thrombophilic alterations (ITA).

METHODS

Between January 2006 and September 2008 ultrasonography assessment of the carotid arteries with measurement of intima-media thickness (IMT), and determination of the ankle/brachial pressure index (ABI), was performed in: a) 161 carriers of ITA (deficiency of antithrombin, protein C or S, factor V Leiden or prothrombin G20210A mutations), 84 of whom with previous VTE, and b) 180 subjects without ITA, matched for age, sex and previous VTE. All subjects were <66 year old.

RESULTS

Carotid plaques were found in 8 subjects [3 (1.9%) with ITA]. Increased IMT values (>1mm) were detected in 6 subjects with and 1 without thrombophilia (p=0.055). The prevalence of IMT values>90(th) percentile was not different in subjects with/without thrombophilia (15.2% vs 11.6%, p=0.416). At multivariate analysis only age was significantly associated with increased odds ratios for IMT values>90(th) percentile. No subjects had abnormal (<0.9) ABI values.

CONCLUSIONS

The present study, the first to investigate the presence of atherosclerotic markers in relatively young subjects with inherited thrombophilia, did not find a particular prevalence of signs of early atherosclerotic markers in these subjects.

Genomics of heart failure

Cardiovascular disease is the leading cause of death in men and women, and heart failure (HF) is associated with high rates of morbidity and mortality. Most common forms of HF are non-mendelian and the evidence for heritability is modest. Study of the genetic susceptibility to HF has been limited to patients with rare familial forms of HF and candidate gene association studies in patients with distinct subtypes of HF. However, with the completion of the human genome project and the development of the HapMap template, new large-scale genome-wide association studies are possible. This article reviews the status of these and other important developments in genomics, in particular genome-wide sequencing, and other "omics".

Personalized Medicine in Coronary Artery Disease: Insights From Genomic Research

Prior clinical studies have demonstrated that a family history of coronary artery disease (CAD) is associated with future cardiovascular events. Although there are several Mendelian disorders that are associated with CAD, most common forms of CAD are believed to be multifactorial and the result of many genes with small individual effects. The identification of these genes and their variation would be very helpful for the prediction, prevention, and management of CAD; linkage analysis or candidate gene case-control studies have been largely unsuccessful. On the contrary, recent advances in genomic techniques have generated a large amount of deoxyribonucleic acid (DNA)-based information. The link between CAD and inflammation and biological pathways has been highlighted. In particular, several genome-wide association studies have replicated a novel gene marker on chromosome 9p21. The information gained from genomic studies, in combination with clinical data, is expected to refine personalized approaches to assess risk and guide management for CAD. Genetic risk scores derived from several functional single nucleotide polymorphisms (SNPs) or haplotypes in multiple genes may improve the prediction of CAD. Despite the complexity of CAD genetics, steady progress is expected.

Effect of formal statistical significance on the credibility of observational associations

The author evaluated the implications of nominal statistical significance for changing the credibility of null versus alternative hypotheses across a large number of observational associations for which formal statistical significance (p < 0.05) was claimed. Calculation of the Bayes factor (B) under different assumptions was performed on 272 observational associations published in 2004-2005 and a data set of 50 meta-analyses on gene-disease associations (752 studies) for which statistically significant associations had been claimed (p < 0.05). Depending on the formulation of the prior, statistically significant results offered less than strong support to the credibility (B > 0.10) for 54-77% of the 272 epidemiologic associations for diverse risk factors and 44-70% of the 50 associations from genetic meta-analyses. Sometimes nominally statistically significant results even decreased the credibility of the probed association in comparison with what was thought before the study was conducted. Five of six meta-analyses with less than substantial support (B > 0.032) lost their nominal statistical significance in a subsequent (more recent) meta-analysis, while this did not occur in any of seven meta-analyses with decisive support (B < 0.01). In these large data sets of observational associations, formal statistical significance alone failed to increase much the credibility of many postulated associations. Bayes factors may be used routinely to interpret "significant" associations.

Polymorphisms in coagulation factors and the risk of recurrent cardiovascular events in men after a first myocardial infarction

BACKGROUND

The aim of this study was to examine whether genetic predisposition to high levels of coagulation factors influences the risk of developing fatal and non-fatal arterial cardiovascular events in men with a first myocardial infarction (MI).

METHODS

We performed a cohort study among 542 MI patients with a mean age of 56 years (range 32-70 years) at the time of the event. All of the men had a first MI between 1990 and 1996 and were followed until 1 September 2004. DNA was analyzed for polymorphisms of fibrinogen, prothrombin (factor II), factor V, factor VII and plasminogen activator inhibitor type 1, all of which are associated with gain of function of the protein. We collected information from hospital files and general practitioners on the occurrence of major arterial events.

RESULTS

In total, 254 major arterial cardiovascular events occurred during a median follow-up period of 11 years (range 0.2-15 years). The point estimates of the relative rates (RRs) of these events for the variant genotypes were all between 0.7 and 1.1 except for the prothrombin 20210A mutation: RR 1.8 (95% confidence interval 0.8-4.1).

CONCLUSION

These findings suggest that there is no association between coagulation factor polymorphisms, previously associated with plasma levels, and the risk of recurrent cardiovascular events.

The Mediterranean paradox for susceptibility factors in coronary heart disease extends to genetics

The incidence of coronary heart disease (CHD) shows a North to South gradient in Europe. We tested whether that gradient could be accounted for by the distribution of putative susceptibility genotypes. We correlated the published frequencies of susceptibility genotypes for the genes most often associated with CHD (ACE, AGT, APOE, F2, F5, MTHFR, PON1, and SERPINE1) with the incidence of the disease, controlling for the effects of smoking, systolic pressure, total cholesterol, and body-mass index. In three polymorphisms a negative correlation between the incidence of CHD and the frequency of a suceptibility genotype was observed. For ACE this correlation was significantly negative even when discounting classical susceptibility factors. This suggests that some alleles described as susceptibility factors cannot account for disease incidence at the population level. A genetic component must be added to the "Mediterranean paradox": genetic variants deemed to be risk factors for CHD show a geographical pattern uncorrelated with the disease incidence. This pattern can be understood from the history of populations which has shaped the genetic diversity of the European populations in North-South clines, similar to what is observed for CHD incidence, which will tend to create spurious correlations with polymorphisms related, or not related, to the disease.

Relevance of Genetics and Genomics for Prevention and Treatment of Cardiovascular Disease

Atherosclerotic cardiovascular disease (CVD) is a major health problem in the United States and around the world. Evidence accumulated over decades convincingly demonstrates that family history in a parent or a sibling is associated with atherosclerotic CVD, manifested as coronary heart disease, stroke, and/or peripheral arterial disease. Although there are several mendelian disorders that contribute to CVD, most common forms of CVD are believed to be multifactorial and to result from many genes, each with a relatively small effect working alone or in combination with modifier genes and/or environmental factors. The identification and the characterization of these genes and their modifiers would enhance prediction of CVD risk and improve prevention, treatment, and quality of care. This scientific statement describes the approaches researchers are using to advance understanding of the genetic basis of CVD and details the current state of knowledge regarding the genetics of myocardial infarction, atherosclerotic CVD, hypercholesterolemia, and hypertension. Current areas of interest and investigation--including gene-environment interaction, pharmacogenetics, and genetic counseling--are also discussed. The statement concludes with a list of specific recommendations intended to help incorporate usable knowledge into current clinical and public health practice, foster and guide future research, and prepare both researchers and practitioners for the changes likely to occur as molecular genetics moves from the laboratory to clinic.

A prospective cohort study on the absolute incidence of venous thromboembolism and arterial cardiovascular disease in asymptomatic carriers of the prothrombin 20210A mutation

The prothrombin 20210A mutation has been associated with an increased risk for venous thromboembolism (VTE) and arterial cardiovascular disease. The risks for asymptomatic carriers of this mutation have thus far been studied only in case-control and retrospective cohort studies. Here we present the results of the first prospective observational study in asymptomatic first-degree family members of patients with either VTE or premature atherosclerosis and the prothrombin 20210A mutation. We included 464 individuals (236 carriers) with a total follow-up duration of 1816 years (943 years for the carriers). The annual incidence of a first VTE was 0.37% (95% CI, 0.08-1.08) for carriers and 0.12% (95% CI, 0.00-0.69) for noncarriers (HR, 3.1; 95% CI, 0.3-29.6). The annual incidence of a first arterial cardiovascular event was 0.56% (95% CI, 0.18-1.31) for carriers and 0.73% (95% CI, 0.27-1.58) for noncarriers (adjusted HR, 0.7; 95% CI, 0.2-2.5). We conclude that the absolute incidence of a first VTE or arterial cardiovascular event is low; therefore, the clinical implications of carriership of the prothrombin 20210A mutation are limited, and routinely testing all first-degree relatives of probands with this mutation does not appear to be justified.

Investigating the Genetic Determinants of Cardiovascular Disease Using Candidate Genes and Meta-analysis of Association Studies

Coronary artery disease (CAD) has a polygenic basis, and identification of CAD susceptibility genes has the potential to aid the development of new treatments and enhance prediction of disease risk. Thus far, the strategy has firstly been to choose "candidate" genes coding for important "rate-limiting" proteins in the homeostatic systems involved in maintaining cardiovascular health; secondly to identify common variants in these candidate genes; thirdly to carry out genotyping and statistical analysis using genetic association studies; and finally to test the functional effects of the identified variants in vitro and in vivo. However, lack of reproducibility of genetic association studies has led to uncertainty about the nature and number of genes involved. In part this is because many of the studies conducted have not been adequately powered to detect small risk effects, or to permit adequate exploration of gene-gene or gene-environment interactions in a robust manner. Spurious positive and negative associations due to type I and type II statistical errors are likely to co-exist with real associations in the published literature. By utilising all available data to increase statistical power, meta-analysis of genetic association studies is increasingly being used to identify genotypic risk with a greater degree of precision. Though potentially powerful, this approach may be prone to publication bias. Therefore, very large genetic association studies will also be required to identify risk genes for CAD. This review lays out the framework for the candidate gene approach for CAD and illustrates this with published results from a UK prospective study of 3000 middle-aged men.

Seven haemostatic gene polymorphisms in coronary disease: meta-analysis of 66,155 cases and 91,307 controls

BACKGROUND

Variants of certain haemostatic genes (such as that encoding factor V Leiden) are involved in the development of venous thrombosis, but studies of such variants in coronary disease have reported apparently conflicting results. We did meta-analyses on seven such haemostatic genetic variants for which the available evidence on each comprises at least 5000 coronary disease cases and at least 5000 controls.

METHODS

Meta-analyses were done of 191 studies in relation to factor V G1691A (ie, factor V Leiden), factor VII G10976A, prothrombin G20210A, plasminogen activator inhibitor-1 (PAI-1) [-675] 4G/5G, and three platelet glycoprotein (GP) receptor variants (GPIa C807T, GPIbalpha T[-5]C, GPIIIa C1565T), involving a total of 66 155 coronary disease cases and 91 307 controls. We explored potential sources of heterogeneity.

FINDINGS

In a combined analysis of all studies, the per-allele relative risks (RR) for coronary disease of factor V 1691A and of prothrombin 20210A were 1.17 (95% CI 1.08-1.28) and 1.31 (1.12-1.52), respectively. Combined analyses of studies of the PAI-1 [-675] 4G variant yielded a per-allele relative risk for coronary disease of 1.06 (1.02-1.10), but there was an indication of publication bias in these studies. Combined analyses of the factor VII 10976A, GPIa 807T, GPIbalpha [-5]C, and GPIIIa 1565T variants showed no significant overall associations with coronary disease, yielding per-allele RRs of 0.97 (0.91-1.04), 1.02 (0.97-1.08), 1.05 (0.96-1.13), and 1.03 (0.98-1.07), respectively.

INTERPRETATION

The 1691A variant of the factor V gene and the 20210A variant of the prothrombin gene, both of which increase circulating thrombin generation, might each be moderately associated with the risk of coronary disease. Further studies are merited to assess these associations in greater detail (including any gene-gene and gene-environment interactions) and to determine any implications with regard to potential therapies designed to reverse patients' prothrombotic phenotype, such as selective plasma factor V or factor Xa inhibition.

Genomic medicine and thrombotic risk: Who, when, how and why?

Major advances in Human Genome research could significantly change the clinical medical practice, providing new possibilities for both diagnosing and treating common pathologies. Many genetic tests are now commercially available for predicting future risk of common disorders. However, genetic testing has potential benefits but also limitations for the patients, and it should not be used to 'screen' the general population. Diagnostic assays for a predisposition of both venous and arterial thrombosis are among the most requested genetic tests in molecular diagnostics laboratories. However, there is considerable uncertainty as to how this information should be utilized in patient management. Both the medical community and the patients need to obtain accurate information concerning the appropriate use of genetic testing. The purpose of this article is to discuss the usefulness and the practical applications of thrombotic genetic testing in order to define which patients should be tested for both venous and arterial thrombotic risk as well as to have an acceptable cost/benefit ratio and to prevent patients' anxiety.

Implications of emerging risk factors for therapeutic intervention

Recently, the National Cholesterol Education Panel (NCEP) of the United States of America commented on the implications of new clinical trials for the Adult Treatment Panel III (ATP III) guidelines. In this commentary, new categories of "moderately high" and "very high" coronary risk were proposed with new "therapeutic options" for low-density lipoprotein (LDL) cholesterol of < or = 100 mg/dL and < or = 70 mg/dL respectively. In ATP III, these "moderately high" risk patients had been classified as moderate risk with an LDL treatment goal of < or = 130 mg/dL, while the "very high" risk patients had been classified as high risk with a treatment goal of < or = 100 mg/dL. Risk classification in the new NCEP publication is based essentially on the combination of the Framingham risk score plus counting of classical risk factors. In the present document, the International Task Force for Prevention of Coronary Heart Disease responds to this NCEP commentary and supports the suggestion of more intensive LDL cholesterol lowering in particular cases. However, the Task Force feels that a classification based on a combination of a risk score plus a count of emerging risk factors is a more logical way to identify such patients requiring lower LDL cholesterol levels than a scheme in which classical risk factors are taken into account twice, once in a count and once in a risk score.

Genetic Determinants of Cardiovascular Disease Risk in Familial Hypercholesterolemia

OBJECTIVE

To investigate the contribution of polymorphisms in multiple candidate genes to cardiovascular disease (CVD) risk in a large cohort of patients with heterozygous familial hypercholesterolemia (FH).

METHODS AND RESULTS

We genotyped 1940 FH patients for 65 polymorphisms in 36 candidate genes. During 91.451 person-years, 643 (33.1%) patients had at least 1 cardiovascular event. Multifactorial Cox survival analysis revealed that the G20210A polymorphism in the prothrombin gene was strongly associated with a significantly increased CVD risk (GA versus GG; P<0.001).

CONCLUSIONS

In a large cohort of FH patients, we found that the G20210A polymorphism in the prothrombin gene is strongly associated with CVD risk. Our results constitute a step forward in the unraveling of the hereditary propensity toward CVD in FH and might lead to better risk stratification and hence to more tailored therapy for CVD prevention.