Impact of COVID-19 pandemic on the occurrence and outcome of cardiogenic shock complicating acute myocardial infarction

Background

The COVID-19 pandemic had influenced the patient's behavior and impacted the homeostasis to a pro-thrombotic niveau.

Aim

The study aimed to follow the impact of COVID-19 on the incidence and prognosis of cardiogenic shock complicated initially acute myocardial infarction (CS-AMI).

Methods

We used data entered into a large national all-comers registry of coronary intervention over five years. From 1/2016 to 12/2020, 50,745 AMI patients were included, and 2,822 (5.6%) initially had CS.

Results

The incidence of CS-AMI was significantly higher in the COVID period (2020) than the mean incidence in 2016–2019 (5.5% vs 6%, p=0.032). The difference was caused by significant increase of CS in acute STEMI (7.6% vs. 8.7%, p=0.011); it was 7.1% in 2016, 7.8% (2017), 7.6% (2018), 7.8% (2019), and 8.7% (2020). The CS complicated 2.3% (2016), 2.7% (2017), 2.7% (2018), 2.8% (2019), and 2.8% (2020) of NSTEMI.

The observed rise in CS-STEMI incidence each month during the pandemic compared to the average incidence in non-pandemic years correlated with the substantial increase in the number of COVID infected/hospitalized (Table 1). In these months, no changes in time delay to reperfusion layout were observed in CS-STEMI patients (Table 2).

Except of less frequent history of previous PCI (13.9% and 8.2%, p<0.001), we found no significant differences in the followed CS-STEMI patient characteristics in 2016–2019 and 2020; men 72.7% and 75.4% (p=0.1), mean age (SD) 66.3 (12.3)yrs and 66.3 (12.2) yrs, Diabetes 20.9% and 19.1% (p=0.2), CKD 5.4% and 5.7% (p=0.4), previous CABG 4.5 and 4.2% (p=0.5), left main disease (14.3% and 16%, p=0.5), one vessel disease 24.9% and 32.1% (p=0.9), pre-PCI TIMI flow 0 64.4% and 66.2% (p=0.6), post-PCI TIMI flow 3 76.7% and 76.9%.

The COVID pandemic didn't influence the proportions of pre-hospital resuscitated CS-AMI patients (57.5% and 58.7%, p=0.6) and those on mechanical ventilation (67.8% and 68.3%, p=0.8).

The 30-day mortality trend of CS-AMI was 53.7% in 2016, 51.6% (2017), 49.7% (2018), 49.3% (2019), and 47.9% (2020). And in CS-STEMI it was 50.8%, 47.1%, 46.4%, 44.1%, and 45.3% (P2019 vs. 2020 =0.8), respectively.

Conclusion

Data from a large national all-comer registry showed an increase in the proportion of patients admitted to hospitals with STEMI complicated by CS in the year of the COVID pandemic. The CS rise correlated with the increase in the COVID infected population. Factors other than the patient's cardiovascular risk profile or prolongation of a time delay to reperfusion influenced this trend. We suggest that the availability of health care and patient adherence may have affected the risks control. We did not observe any effect of the pandemic on CS-AMI mortality.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Ministry of Health of the Czech Republic

All-cause mortality of patients with STEMI, cardiogenic shock and multivessel coronary disease treated with culprit vessel only versus multivessel primary PCI

Background

Patients with ST elevation myocardial infarction (STEMI) and cardiogenic shock (CS) treated with primary percutaneous coronary intervention (pPCI) have high mortality. A recent trial demonstrated that a culprit vessel-only strategy (CV-pPCI) was superior to immediate multivessel PCI (MV-pPCI) for patients with CS and multivessel coronary artery disease (MVD). Irrespective of it and current guidelines, multivessel PCI is still often used in these patients.

Purpose/Methods

The study aimed to compare the characteristics and prognosis of patients with CS-STEMI and MVD treated with culprit vessel only pPCI or multivessel PCI during initial procedure. From 2016 to 2020, 23703 primary PCI patients with STEMI were included in the national all-comers registry of cardiovascular interventions. From them, a total of 1213 (5.1%) patients had cardiogenic shock and MVD at admission to the hospital. Initially 921 (75.9%) patients were treated with CV-pPCI and 292 (24.1%) with MV-pPCI.

Results

CV-pPCI was a preferred strategy to MV-pPCI in men (74.6% vs 25.4%; p<0,001) and women (79.8% vs 20.2%; p<0,001) with CS-STEMI and MVD. Patients with 3-vessel disease and left main disease had higher probability to be treated with MV-pPCI than patients with 2-vessel disease and without left main disease (28.5% vs 18.6%; p<0,001 and 37.7% vs 20.6%; p<0,001).The CV-pPCI and MV-pPCI group patients did not differ in age (68.1±11.2 vs 66.2±11.4 years; p=0.780), previous PCI (16.1% vs 12.0%; p=0.890) and CABG (6.2% vs 4.8%; p=0.376), chronic kidney disease (6.8% vs 8.2%; p=0.426), cardiopulmonary resuscitation (60.4% vs 58.9%; p=0.657) and pulmonary ventilation (66.8% vs 70.5%; p=0.227) at admission, localization of myocardial infarction (anterior 50.8.% vs 58.9%; p=0.671), time to reperfusion (<2 hours 5.2% vs 4.8%; p=0.722) and TIMI flow 0 before PCI (63.1% vs 64.0%; p=0.675). Based on the results of logistic regression analysis, 30-days (odds ratio, 0.99; 95% CI 0.76 to 1.29; p=0.937) and 1-year (odds ratio, 0.91; 95% CI 0.69 to 1.19; p=0.477) all-cause mortality rates were similar in CV-pPCI and MV-pPCI groups. The presence of 3-vessel disease was the strongest adjusted predictor of 30-days (odds ratio, 1.61; 95% CI 1.27 to 2.04; p<0.001) and 1-year (odds ratio, 1.64; 95% CI 1.30 to 2.08; p<0.001) all-cause mortality in patients with STEMI and CS treated with pPCI.

Conclusion

Immediate multivessel primary PCI is still used in patients with CS-STEMI and MVD in routine clinical practice. We did not find difference in 30-days and 1-year mortality among patients with CS-STEMI and MVD treated either with culprit vessel-only or multivessel primary PCI.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): NV19-02-00086 supported by Ministry of Health of the Czech Republic

Echocardiography is inferior to computed tomography in predicting balloon expandable transcutaneous implantation valve size in routine clinical setting-single centre study

Funding Acknowledgements

Type of funding sources: None.

Background

Transcatheter aortic valve replacement (TAVR) became standard of care for selected patients with severe aortic stenosis. Computed tomography (CT) and 2D/3D echocardiography (ECHO) are used for aortic annulus sizing. As a result of increasing number of TAVR more imaging specialists participate in pre-procedural TAVR assessment.

Purpose

The aim of this study was to compare accuracy of ECHO aortic annulus measurements vs CT based parameters for Edward Sapiens TAVR in such environment.

Methods

Data of 145 consecutive patients with TAVR (Sapiens XT or Sapiens 3S) were analysed retrospectively. One radiologist and six echocardiographers trained in aortic annulus size measurements participated in pre-procedural aortic anulus assessment. Aortic annulus area and area derived diameter were measured/calculated in each patient from 3D ECHO data set acquired from mid-oesophageal view and from CT data set, using multiplanar reconstruction. 2D ECHO aortic annulus size was measured from mid-oesophageal 120º view in early systole. 

Results

139 (96%) patients had favourable TAVR result (max. mild aortic regurgitation, single valve implanted). 3D ECHO aortic anulus area and area derived diameter were smaller than corresponding CT parameters (464 ± 99 vs 479 ± 88 mm2, p < 0.001 and 24.2 ± 2.7 mm vs 25.0 ± 5.5, p = 0.002, respectively) and differed between echocardiographers (p < 0.001). 2D ECHO anulus measurement were smaller in comparison to both CT and 3D ECHO area derived diameter (22.6 ± 2.9 vs 25.0 ± 5.5mm, p = 0,013 and 22.6 ± 2.9 vs 24.2± 2.7mm, p < 0.001, respectively). In implanted valves with favourable procedure result, concordance of CT and 3D ECHO aortic annulus area with manufacturer recommended ranges was 79.4% vs 61% (p= 0.001) and for area derived diameter 80.1% vs 61.7% (p = 0.001). Using 3D ECHO measurements 33% of the patients would have hypothetically received inappropriate valve size.

Conclusion

3D ECHO aortic annulus measurements are generally smaller then CT ones. If 3D ECHO based parameters only were used for TAVR (Edward Sapiens) size selection, it would have resulted in underestimation of the valve size in up to 1/3 of the patients. CT aortic annulus size assessment should be preferred method over 3D ECHO in daily practice. Abstract Figure 1  Abstract Table 1

Genome-wide meta-analysis of variant-by-diuretic interactions as modulators of lipid traits in persons of European and African ancestry

Hypertension (HTN) is a significant risk factor for cardiovascular morbidity and mortality. Metabolic abnormalities, including adverse cholesterol and triglycerides (TG) profiles, are frequent comorbid findings with HTN and contribute to cardiovascular disease. Diuretics, which are used to treat HTN and heart failure, have been associated with worsening of fasting lipid concentrations. Genome-wide meta-analyses with 39,710 European-ancestry (EA) individuals and 9,925 African-ancestry (AA) individuals were performed to identify genetic variants that modify the effect of loop or thiazide diuretic use on blood lipid concentrations. Both longitudinal and cross-sectional data were used to compute cohort-specific interaction results, which were then combined through meta-analysis in each ancestry. These ancestry-specific results were further combined through trans-ancestry meta-analysis. Analysis of EA data identified two genome-wide significant (p < 5×10⁻⁸) loci with single nucleotide variant (SNV)-loop diuretic interaction on TG concentrations (including COL11A1). Analysis of AA data identified one genome-wide significant locus adjacent to BMP2 with SNV-loop diuretic interaction on TG concentrations. Trans-ancestry analysis strengthened evidence of association for SNV-loop diuretic interaction at two loci (KIAA1217 and BAALC). There were few significant SNV-thiazide diuretic interaction associations on TG concentrations and for either diuretic on cholesterol concentrations. Several promising loci were identified that may implicate biologic pathways that contribute to adverse metabolic side effects from diuretic therapy.

Pharmacogenomics study of thiazide diuretics and QT interval in multi-ethnic populations: the cohorts for heart and aging research in genomic epidemiology

Thiazide diuretics, commonly used antihypertensives, may cause QT interval (QT) prolongation, a risk factor for highly fatal and difficult to predict ventricular arrhythmias. We examined whether common single-nucleotide polymorphisms (SNPs) modified the association between thiazide use and QT or its component parts (QRS interval, JT interval) by performing ancestry-specific, trans-ethnic and cross-phenotype genome-wide analyses of European (66%), African American (15%) and Hispanic (19%) populations (N=78 199), leveraging longitudinal data, incorporating corrected standard errors to account for underestimation of interaction estimate variances and evaluating evidence for pathway enrichment. Although no loci achieved genome-wide significance (P<5 × 10-8), we found suggestive evidence (P<5 × 10-6) for SNPs modifying the thiazide-QT association at 22 loci, including ion transport loci (for example, NELL1, KCNQ3). The biologic plausibility of our suggestive results and simulations demonstrating modest power to detect interaction effects at genome-wide significant levels indicate that larger studies and innovative statistical methods are warranted in future efforts evaluating thiazide-SNP interactions.

GWAS for executive function and processing speed suggests involvement of the CADM2 gene

To identify common variants contributing to normal variation in two specific domains of cognitive functioning, we conducted a genome-wide association study (GWAS) of executive functioning and information processing speed in non-demented older adults from the CHARGE (Cohorts for Heart and Aging Research in Genomic Epidemiology) consortium. Neuropsychological testing was available for 5429-32,070 subjects of European ancestry aged 45 years or older, free of dementia and clinical stroke at the time of cognitive testing from 20 cohorts in the discovery phase. We analyzed performance on the Trail Making Test parts A and B, the Letter Digit Substitution Test (LDST), the Digit Symbol Substitution Task (DSST), semantic and phonemic fluency tests, and the Stroop Color and Word Test. Replication was sought in 1311-21860 subjects from 20 independent cohorts. A significant association was observed in the discovery cohorts for the single-nucleotide polymorphism (SNP) rs17518584 (discovery P-value=3.12 × 10(-8)) and in the joint discovery and replication meta-analysis (P-value=3.28 × 10(-9) after adjustment for age, gender and education) in an intron of the gene cell adhesion molecule 2 (CADM2) for performance on the LDST/DSST. Rs17518584 is located about 170 kb upstream of the transcription start site of the major transcript for the CADM2 gene, but is within an intron of a variant transcript that includes an alternative first exon. The variant is associated with expression of CADM2 in the cingulate cortex (P-value=4 × 10(-4)). The protein encoded by CADM2 is involved in glutamate signaling (P-value=7.22 × 10(-15)), gamma-aminobutyric acid (GABA) transport (P-value=1.36 × 10(-11)) and neuron cell-cell adhesion (P-value=1.48 × 10(-13)). Our findings suggest that genetic variation in the CADM2 gene is associated with individual differences in information processing speed.

Genetic contributions to variation in general cognitive function: a meta-analysis of genome-wide association studies in the CHARGE consortium (N=53949)

General cognitive function is substantially heritable across the human life course from adolescence to old age. We investigated the genetic contribution to variation in this important, health- and well-being-related trait in middle-aged and older adults. We conducted a meta-analysis of genome-wide association studies of 31 cohorts (N=53,949) in which the participants had undertaken multiple, diverse cognitive tests. A general cognitive function phenotype was tested for, and created in each cohort by principal component analysis. We report 13 genome-wide significant single-nucleotide polymorphism (SNP) associations in three genomic regions, 6q16.1, 14q12 and 19q13.32 (best SNP and closest gene, respectively: rs10457441, P=3.93 × 10(-9), MIR2113; rs17522122, P=2.55 × 10(-8), AKAP6; rs10119, P=5.67 × 10(-9), APOE/TOMM40). We report one gene-based significant association with the HMGN1 gene located on chromosome 21 (P=1 × 10(-6)). These genes have previously been associated with neuropsychiatric phenotypes. Meta-analysis results are consistent with a polygenic model of inheritance. To estimate SNP-based heritability, the genome-wide complex trait analysis procedure was applied to two large cohorts, the Atherosclerosis Risk in Communities Study (N=6617) and the Health and Retirement Study (N=5976). The proportion of phenotypic variation accounted for by all genotyped common SNPs was 29% (s.e.=5%) and 28% (s.e.=7%), respectively. Using polygenic prediction analysis, ~1.2% of the variance in general cognitive function was predicted in the Generation Scotland cohort (N=5487; P=1.5 × 10(-17)). In hypothesis-driven tests, there was significant association between general cognitive function and four genes previously associated with Alzheimer's disease: TOMM40, APOE, ABCG1 and MEF2C.

A genome-wide association meta-analysis of plasma Aβ peptides concentrations in the elderly

Amyloid beta (Aβ) peptides are the major components of senile plaques, one of the main pathological hallmarks of Alzheimer disease (AD). However, Aβ peptides' functions are not fully understood and seem to be highly pleiotropic. We hypothesized that plasma Aβ peptides concentrations could be a suitable endophenotype for a genome-wide association study (GWAS) designed to (i) identify novel genetic factors involved in amyloid precursor protein metabolism and (ii) highlight relevant Aβ-related physiological and pathophysiological processes. Hence, we performed a genome-wide association meta-analysis of four studies totaling 3 528 healthy individuals of European descent and for whom plasma Aβ1-40 and Aβ1-42 peptides levels had been quantified. Although we did not observe any genome-wide significant locus, we identified 18 suggestive loci (P<1 × 10(-)(5)). Enrichment-pathway analyses revealed canonical pathways mainly involved in neuronal functions, for example, axonal guidance signaling. We also assessed the biological impact of the gene most strongly associated with plasma Aβ1-42 levels (cortexin 3, CTXN3) on APP metabolism in vitro and found that the gene protein was able to modulate Aβ1-42 secretion. In conclusion, our study results suggest that plasma Aβ peptides levels are valid endophenotypes in GWASs and can be used to characterize the metabolism and functions of APP and its metabolites.

Allelic differences between Europeans and Chinese for CREB1 SNPs and their implications in gene expression regulation, hippocampal structure and function, and bipolar disorder susceptibility

Bipolar disorder (BD) is a polygenic disorder that shares substantial genetic risk factors with major depressive disorder (MDD). Genetic analyses have reported numerous BD susceptibility genes, while some variants, such as single-nucleotide polymorphisms (SNPs) in CACNA1C have been successfully replicated, many others have not and subsequently their effects on the intermediate phenotypes cannot be verified. Here, we studied the MDD-related gene CREB1 in a set of independent BD sample groups of European ancestry (a total of 64,888 subjects) and identified multiple SNPs significantly associated with BD (the most significant being SNP rs6785[A], P=6.32 × 10(-5), odds ratio (OR)=1.090). Risk SNPs were then subjected to further analyses in healthy Europeans for intermediate phenotypes of BD, including hippocampal volume, hippocampal function and cognitive performance. Our results showed that the risk SNPs were significantly associated with hippocampal volume and hippocampal function, with the risk alleles showing a decreased hippocampal volume and diminished activation of the left hippocampus, adding further evidence for their involvement in BD susceptibility. We also found the risk SNPs were strongly associated with CREB1 expression in lymphoblastoid cells (P<0.005) and the prefrontal cortex (P<1.0 × 10(-6)). Remarkably, population genetic analysis indicated that CREB1 displayed striking differences in allele frequencies between continental populations, and the risk alleles were completely absent in East Asian populations. We demonstrated that the regional prevalence of the CREB1 risk alleles in Europeans is likely caused by genetic hitchhiking due to natural selection acting on a nearby gene. Our results suggest that differential population histories due to natural selection on regional populations may lead to genetic heterogeneity of susceptibility to complex diseases, such as BD, and explain inconsistencies in detecting the genetic markers of these diseases among different ethnic populations.

Follow-up of loci from the International Genomics of Alzheimer's Disease Project identifies TRIP4 as a novel susceptibility gene

To follow-up loci discovered by the International Genomics of Alzheimer's Disease Project, we attempted independent replication of 19 single nucleotide polymorphisms (SNPs) in a large Spanish sample (Fundació ACE data set; 1808 patients and 2564 controls). Our results corroborate association with four SNPs located in the genes INPP5D, MEF2C, ZCWPW1 and FERMT2, respectively. Of these, ZCWPW1 was the only SNP to withstand correction for multiple testing (P=0.000655). Furthermore, we identify TRIP4 (rs74615166) as a novel genome-wide significant locus for Alzheimer's disease risk (odds ratio=1.31; confidence interval 95% (1.19-1.44); P=9.74 × 10(-)(9)).

Drug-gene interactions and the search for missing heritability: a cross-sectional pharmacogenomics study of the QT interval

Variability in response to drug use is common and heritable, suggesting that genome-wide pharmacogenomics studies may help explain the 'missing heritability' of complex traits. Here, we describe four independent analyses in 33 781 participants of European ancestry from 10 cohorts that were designed to identify genetic variants modifying the effects of drugs on QT interval duration (QT). Each analysis cross-sectionally examined four therapeutic classes: thiazide diuretics (prevalence of use=13.0%), tri/tetracyclic antidepressants (2.6%), sulfonylurea hypoglycemic agents (2.9%) and QT-prolonging drugs as classified by the University of Arizona Center for Education and Research on Therapeutics (4.4%). Drug-gene interactions were estimated using covariable-adjusted linear regression and results were combined with fixed-effects meta-analysis. Although drug-single-nucleotide polymorphism (SNP) interactions were biologically plausible and variables were well-measured, findings from the four cross-sectional meta-analyses were null (Pinteraction>5.0 × 10(-8)). Simulations suggested that additional efforts, including longitudinal modeling to increase statistical power, are likely needed to identify potentially important pharmacogenomic effects.

Lipoprotein-associated phospholipase A₂ mass level is increased in elderly subjects with type 2 diabetes mellitus

OBJECTIVE. Lipoprotein-associated phospholipase A₂ (Lp-PLA₂) is extensively expressed by advanced atherosclerotic lesions and may play a role in plaque instability. We selected a group of elderly subjects that underwent transcatheter aortic valve implantation (TAVI) or balloon angioplasty (BA) and separated them into two groups, diabetic and nondiabetic, to compare the level of Lp-PLA₂ mass between them. METHODS. 44 patients aged 79.6 ± 5.6 years with symptomatic severe aortic valve stenosis underwent TAVI (n = 35) or BA (n = 9). 21 subjects had confirmed type 2 diabetes mellitus. Lp-PLA₂ mass was measured using an enzyme-linked immunosorbent assay kit (USCN Life Science, China) before and 3 days after the procedure. RESULTS. Lp-PLA₂ mass was significantly elevated in this population (1296 ± 358 ng/mL before TAVI; 1413 ± 268 ng/mL before BA) and further increased after TAVI (1604 ± 437 ng/mL, P < 0.01) or BA (1808 ± 303 ng/mL, P < 0.01). Lp-PLA₂ mass was significantly increased on the diabetic group before these interventions. CONCLUSION. Lp-PLA₂ may be a novel biomarker for the presence of rupture-prone atherosclerotic lesions in elderly patients. Levels of Lp-PLA₂ in diabetic patients may accompany the higher amount of small dense LDL particles seen in these subjects.

Meta-analysis of 74,046 individuals identifies 11 new susceptibility loci for Alzheimer's disease

Eleven susceptibility loci for late-onset Alzheimer's disease (LOAD) were identified by previous studies; however, a large portion of the genetic risk for this disease remains unexplained. We conducted a large, two-stage meta-analysis of genome-wide association studies (GWAS) in individuals of European ancestry. In stage 1, we used genotyped and imputed data (7,055,881 SNPs) to perform meta-analysis on 4 previously published GWAS data sets consisting of 17,008 Alzheimer's disease cases and 37,154 controls. In stage 2, 11,632 SNPs were genotyped and tested for association in an independent set of 8,572 Alzheimer's disease cases and 11,312 controls. In addition to the APOE locus (encoding apolipoprotein E), 19 loci reached genome-wide significance (P < 5 × 10(-8)) in the combined stage 1 and stage 2 analysis, of which 11 are newly associated with Alzheimer's disease.

Common genetic variation near the connexin-43 gene is associated with resting heart rate in African Americans: a genome-wide association study of 13,372 participants

BACKGROUND

Genome-wide association studies have identified several genetic loci associated with variation in resting heart rate in European and Asian populations. No study has evaluated genetic variants associated with heart rate in African Americans.

OBJECTIVE

To identify novel genetic variants associated with resting heart rate in African Americans.

METHODS

Ten cohort studies participating in the Candidate-gene Association Resource and Continental Origins and Genetic Epidemiology Network consortia performed genome-wide genotyping of single nucleotide polymorphisms (SNPs) and imputed 2,954,965 SNPs using HapMap YRI and CEU panels in 13,372 participants of African ancestry. Each study measured the RR interval (ms) from 10-second resting 12-lead electrocardiograms and estimated RR-SNP associations using covariate-adjusted linear regression. Random-effects meta-analysis was used to combine cohort-specific measures of association and identify genome-wide significant loci (P≤2.5×10(-8)).

RESULTS

Fourteen SNPs on chromosome 6q22 exceeded the genome-wide significance threshold. The most significant association was for rs9320841 (+13 ms per minor allele; P = 4.98×10(-15)). This SNP was approximately 350 kb downstream of GJA1, a locus previously identified as harboring SNPs associated with heart rate in Europeans. Adjustment for rs9320841 also attenuated the association between the remaining 13 SNPs in this region and heart rate. In addition, SNPs in MYH6, which have been identified in European genome-wide association study, were associated with similar changes in the resting heart rate as this population of African Americans.

CONCLUSIONS

An intergenic region downstream of GJA1 (the gene encoding connexin 43, the major protein of the human myocardial gap junction) and an intragenic region within MYH6 are associated with variation in resting heart rate in African Americans as well as in populations of European and Asian origin.

Failure of noninvasive prediction of pulmonary hypertension in patients with idiopathic pulmonary fibrosis

BACKGROUND

Pulmonary hypertension (PH) in patients with advanced idiopathic pulmonary fibrosis (IPF) is a complication connected with unfavorable prognosis. Great efforts have been made in attempting to establish a reliable non-invasive method which would enable detection of this complication. In this context a formula using pulmonary function parameters was published with outstanding results.

METHODS

We tested the formula in 27 IPF patients who underwent a lung function examination, cardiac ultrasonography and catheterisation on the same day.

RESULTS

Pulmonary hypertension was detected by catheterisation in 17 patients (63%). In our group, contrary to the published data, the aforementioned formula was neither useful for detecting patients with a high probability of PH nor as a means of calculating the mean pulmonary artery pressure in individual patients (p = 0.502 and p = 0.833, respectively). Ultrasound examination reached borderline correlation with the values measured by catheterisation when we compare patients with relevant results (r = 0.531, p = 0.051). However, the examination gave no usable results in 13 patients (48%).

CONCLUSION

Our data suggests that no reliable, noninvasive method is currently available for detecting and confirming PH in IPF patients. We did not confirm the usefulness of the published formula. Further carefully organised studies will be necessary to verify or refute it.

Bayesian methods for meta-analysis of causal relationships estimated using genetic instrumental variables

Genetic markers can be used as instrumental variables, in an analogous way to randomization in a clinical trial, to estimate the causal relationship between a phenotype and an outcome variable. Our purpose is to extend the existing methods for such Mendelian randomization studies to the context of multiple genetic markers measured in multiple studies, based on the analysis of individual participant data. First, for a single genetic marker in one study, we show that the usual ratio of coefficients approach can be reformulated as a regression with heterogeneous error in the explanatory variable. This can be implemented using a Bayesian approach, which is next extended to include multiple genetic markers. We then propose a hierarchical model for undertaking a meta-analysis of multiple studies, in which it is not necessary that the same genetic markers are measured in each study. This provides an overall estimate of the causal relationship between the phenotype and the outcome, and an assessment of its heterogeneity across studies. As an example, we estimate the causal relationship of blood concentrations of C-reactive protein on fibrinogen levels using data from 11 studies. These methods provide a flexible framework for efficient estimation of causal relationships derived from multiple studies. Issues discussed include weak instrument bias, analysis of binary outcome data such as disease risk, missing genetic data, and the use of haplotypes.

Genome-wide association studies of cardiovascular risk factors: design, conduct and interpretation

Relying on known biology, candidate-gene studies have been only modestly successful in identifying genetic variants associated with cardiovascular risk factors. Genome-wide association (GWA) studies, in contrast, allow broad scans across millions of loci in search of unsuspected genetic associations with phenotypes. The large numbers of statistical tests in GWA studies and the large sample sizes required to detect modest-sized associations have served as a powerful incentive for the development of large collaborative efforts such as the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) Consortium. This article uses published data on three phenotypes, fibrinogen, uric acid, and electrocardiographic QT interval duration, from the CHARGE Consortium to describe several methodologic issues in the design, conduct, and interpretation of GWA studies, including the use of imputation and the need for additional genotyping. Even with large studies, novel genetic loci explain only a small proportion of the variance of cardiovascular phenotypes.

Time-course of tissue factor plasma level in patients with acute coronary syndrome

Enhanced expression of tissue factor (TF) may result in thrombosis contributing to acute clinical consequences of coronary artery disease. Several studies demonstrated elevated plasma levels of TF in patients with acute coronary syndrome (ACS). The aim of our study was to compare the concentrations of TF in coronary sinus (CS), proximal part of the left coronary artery (LCA) and peripheral vein (PV) of patients with ACS and stable coronary artery disease (SCAD). Time course of the TF plasma levels in PV was followed on day 1 and day 7 after index event of ACS presentation and was compared to day 0 values. No heparin was given prior to the blood sampling. Twenty-nine patients in the ACS group (age 63.6+/-10.8 years, 20 males, 9 females) and 24 patients with SCAD (age 62.3+/-8.1 years, 21 males, 3 females) were examined. TF plasma level was significantly higher in patients with ACS than in those with SCAD (239.0+/-99.3 ng/ml vs. 164.3+/-114.2 ng/ml; p=0.016). There was no difference in TF plasma levels in PV, CS and LCA (239.0+/-99.3 ng/ml vs. 253.7+/-131.5 ng/ml vs. 250.6+/-116.4 ng/ml, respectively). TF plasma levels tended to decrease only non-significantly on the day 7 (224.4+/-109.8 ng/ml). Significant linear correlation between TF and high sensitivity CRP (hs-CRP) levels on day 0 was found. In conclusion, TF plasma levels are elevated in patients with ACS not only locally in CS but also in systematic circulation. Our data support the relationship between TF production and proinflammatory mediators.

Variation in 24 hemostatic genes and associations with non-fatal myocardial infarction and ischemic stroke

BACKGROUND

Arterial thrombosis involves platelet aggregation and clot formation, yet little is known about the contribution of genetic variation in fibrin-based hemostatic factors to arterial clotting risk. We hypothesized that common variation in 24 coagulation-fibrinolysis genes would contribute to risk of incident myocardial infarction (MI) or ischemic stroke (IS).

METHODS

We conducted a population-based, case-control study. Subjects were hypertensive adults and postmenopausal women 30-79 years of age, who sustained a first MI (n = 856) or IS (n = 368) between 1995 and 2002, and controls matched on age, hypertension status, and calendar year (n = 2,689). We investigated the risk of MI and IS associated with (i) global variation within each gene as measured by common haplotypes and (ii) individual haplotypes and single nucleotide polymorphisms (SNPs). Significance was assessed using a 0.2 threshold of the false discovery rate q-value, which accounts for multiple testing.

RESULTS

After accounting for multiple testing, global genetic variation in factor (F) VIII was associated with IS risk. Two haplotypes in FVIII and one in FXIIIa1 were significantly associated with increased IS risk (all q-values < 0.2). A plasminogen gene SNP was associated with MI risk. All are new discoveries not previously reported. Another 24 tests had P-values < 0.05 and q-values > 0.2 in MI and IS analyses, 23 of which are new and hypothesis generating.

CONCLUSIONS

Apart from the association of FVIII variation with IS, we found little evidence that common variation in the 24 candidate fibrin-based hemostasis genes strongly influences arterial thrombotic risk, but our results cannot rule out small effects.

Plasma tissue factor in coronary artery disease: further step to the understanding of the basic mechanisms of coronary artery thrombosis

Tissue factor is a cell surface protein that is expressed constitutively by monocytes, macrophages and fibroblasts, but also by some other cells in response to a variety of stimuli. The main function of the tissue factor is to form a complex with factor VII/VIIa that converts factors IX and X to their active forms. Tissue factor is also involved in the pathophysiology of systemic inflammatory disorders, coagulopathies, atherosclerotic disease, tumor angiogenesis and metastasis. Increased tissue factor expression either locally in the coronary plaques or systematically on circulating blood elements of patients with acute coronary syndromes may be responsible for increased thrombin generation, thus leading to platelet activation and fibrin formation. Tissue factor therefore plays a pivotal role in the initiation of thrombotic complications in patients with coronary artery disease.

[Cardiogenic shock in acute myocardial infarction--what we know in 2005]

Cardiogenic shock represents a complication in up to 10% of patients with acute myocardial infarction. Cardiogenic shock mortality remains high. In the contemporary treatment inhibitors of NO synthase are studied, apart from classic medications. Mechanical circulatory support is also important in majority of patients with cardiogenic shock: intraaortic balloon contrapulsation, left ventricular assist device systems. Prognosis is improved by percutaneous coronary intervention.

[Ischemia-modified albumin: new marker of myocardial ischemia?]

The Albumin Cobalt Binding Test is a quantitative in vitro diagnostic test used on human serum that detects ischemia-modified albumin by measuring the cobalt binding capacity of albumin in human serum. Ischemia modified albumin is intended for use in conjunction with ECG and cardiac troponin as an aid to short term risk stratification of patients presenting with chest pain suggestive of cardiac origin. Thus, in patients with chest pain or equivalent symptoms suggestive of cardiac origin, with non-diagnostic ECG and normal troponin, a negative IMA can be used as an aid to rule out acute coronary syndrome (ACS) in low risk patients.