Hundreds of variants clustered in genomic loci and biological pathways affect human height

Most common human traits and diseases have a polygenic pattern of inheritance: DNA sequence variants at many genetic loci influence the phenotype. Genome-wide association (GWA) studies have identified more than 600 variants associated with human traits, but these typically explain small fractions of phenotypic variation, raising questions about the use of further studies. Here, using 183,727 individuals, we show that hundreds of genetic variants, in at least 180 loci, influence adult height, a highly heritable and classic polygenic trait. The large number of loci reveals patterns with important implications for genetic studies of common human diseases and traits. First, the 180 loci are not random, but instead are enriched for genes that are connected in biological pathways (P = 0.016) and that underlie skeletal growth defects (P < 0.001). Second, the likely causal gene is often located near the most strongly associated variant: in 13 of 21 loci containing a known skeletal growth gene, that gene was closest to the associated variant. Third, at least 19 loci have multiple independently associated variants, suggesting that allelic heterogeneity is a frequent feature of polygenic traits, that comprehensive explorations of already-discovered loci should discover additional variants and that an appreciable fraction of associated loci may have been identified. Fourth, associated variants are enriched for likely functional effects on genes, being over-represented among variants that alter amino-acid structure of proteins and expression levels of nearby genes. Our data explain approximately 10% of the phenotypic variation in height, and we estimate that unidentified common variants of similar effect sizes would increase this figure to approximately 16% of phenotypic variation (approximately 20% of heritable variation). Although additional approaches are needed to dissect the genetic architecture of polygenic human traits fully, our findings indicate that GWA studies can identify large numbers of loci that implicate biologically relevant genes and pathways.

A catalog of genetic loci associated with kidney function from analyses of a million individuals

Chronic kidney disease (CKD) is responsible for a public health burden with multi-systemic complications. Through trans-ancestry meta-analysis of genome-wide association studies of estimated glomerular filtration rate (eGFR) and independent replication (n = 1,046,070), we identified 264 associated loci (166 new). Of these, 147 were likely to be relevant for kidney function on the basis of associations with the alternative kidney function marker blood urea nitrogen (n = 416,178). Pathway and enrichment analyses, including mouse models with renal phenotypes, support the kidney as the main target organ. A genetic risk score for lower eGFR was associated with clinically diagnosed CKD in 452,264 independent individuals. Colocalization analyses of associations with eGFR among 783,978 European-ancestry individuals and gene expression across 46 human tissues, including tubulo-interstitial and glomerular kidney compartments, identified 17 genes differentially expressed in kidney. Fine-mapping highlighted missense driver variants in 11 genes and kidney-specific regulatory variants. These results provide a comprehensive priority list of molecular targets for translational research.

Target genes, variants, tissues and transcriptional pathways influencing human serum urate levels

Elevated serum urate levels cause gout and correlate with cardiometabolic diseases via poorly understood mechanisms. We performed a trans-ancestry genome-wide association study of serum urate in 457,690 individuals, identifying 183 loci (147 previously unknown) that improve the prediction of gout in an independent cohort of 334,880 individuals. Serum urate showed significant genetic correlations with many cardiometabolic traits, with genetic causality analyses supporting a substantial role for pleiotropy. Enrichment analysis, fine-mapping of urate-associated loci and colocalization with gene expression in 47 tissues implicated the kidney and liver as the main target organs and prioritized potentially causal genes and variants, including the transcriptional master regulators in the liver and kidney, HNF1A and HNF4A. Experimental validation showed that HNF4A transactivated the promoter of ABCG2, encoding a major urate transporter, in kidney cells, and that HNF4A p.Thr139Ile is a functional variant. Transcriptional coregulation within and across organs may be a general mechanism underlying the observed pleiotropy between urate and cardiometabolic traits.

Genome-wide association meta-analyses and fine-mapping elucidate pathways influencing albuminuria

Increased levels of the urinary albumin-to-creatinine ratio (UACR) are associated with higher risk of kidney disease progression and cardiovascular events, but underlying mechanisms are incompletely understood. Here, we conduct trans-ethnic (n = 564,257) and European-ancestry specific meta-analyses of genome-wide association studies of UACR, including ancestry- and diabetes-specific analyses, and identify 68 UACR-associated loci. Genetic correlation analyses and risk score associations in an independent electronic medical records database (n = 192,868) reveal connections with proteinuria, hyperlipidemia, gout, and hypertension. Fine-mapping and trans-Omics analyses with gene expression in 47 tissues and plasma protein levels implicate genes potentially operating through differential expression in kidney (including TGFB1, MUC1, PRKCI, and OAF), and allow coupling of UACR associations to altered plasma OAF concentrations. Knockdown of OAF and PRKCI orthologs in Drosophila nephrocytes reduces albumin endocytosis. Silencing fly PRKCI further impairs slit diaphragm formation. These results generate a priority list of genes and pathways for translational research to reduce albuminuria.

Linkage analysis identifies a novel locus for restless legs syndrome on chromosome 2q in a South Tyrolean population isolate

Restless legs syndrome (RLS) is a common neurological condition with three loci (12q, 14q, and 9p) described so far, although none of these genes has yet been identified. We report a genomewide linkage scan of patients with RLS (n=37) assessed in a population isolate (n=530) of South Tyrol (Italy). Using both nonparametric and parametric analyses, we initially obtained suggestive evidence of a novel locus on chromosome 2q, with nominal evidence of linkage on chromosomes 5p and 17p. Follow-up genotyping yielded significant evidence of linkage (nonparametric LOD score 5.5, P Collapse

Key Words Collapse

MESH Headings

• Adolescent
• Adult
• Child
• Chromosome Mapping
• Chromosomes, Human, Pair 2/genetics
• Family
• Female
• Genetic Linkage
• Genetic Predisposition to Disease
• Genome, Human
• Humans
• Italy
• Lod Score
• Male
• Microsatellite Repeats
• Middle Aged
• Pedigree
• Restless Legs Syndrome/genetics

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The Cooperative Health Research in South Tyrol (CHRIS) study: rationale, objectives, and preliminary results

The Cooperative Health Research In South Tyrol (CHRIS) study is a population-based study with a longitudinal lookout to investigate the genetic and molecular basis of age-related common chronic conditions and their interaction with life style and environment in the general population. All adults of the middle and upper Vinschgau/Val Venosta are invited, while 10,000 participants are anticipated by mid-2017. Family participation is encouraged for complete pedigree reconstruction and disease inheritance mapping. After a pilot study on the compliance with a paperless assessment mode, computer-assisted interviews have been implemented to screen for conditions of the cardiovascular, endocrine, metabolic, genitourinary, nervous, behavioral, and cognitive system. Fat intake, cardiac health, and tremor are assessed instrumentally. Nutrient intake, physical activity, and life-course smoking are measured semi-quantitatively. Participants are phenotyped for 73 blood and urine parameters and 60 aliquots per participant are biobanked (cryo-preserved urine, DNA, and whole and fractionated blood). Through liquid-chromatography mass-spectrometry analysis, metabolite profiling of the mitochondrial function is assessed. Samples are genotyped on 1 million variants with the Illumina HumanOmniExpressExome array and the first data release including 4570 fully phenotyped and genotyped samples is now available for analysis. Participants’ follow-up is foreseen 6 years after the first visit. The target population is characterized by long-term social stability and homogeneous environment which should both favor the identification of enriched genetic variants. The CHRIS cohort is a valuable resource to assess the contribution of genomics, metabolomics, and environmental factors to human health and disease. It is awaited that this will result in the identification of novel molecular targets for disease prevention and treatment.

Comparison of anatomic feasibility of three different multibranched off-the-shelf stent-grafts designed for thoracoabdominal aortic aneurysms

OBJECTIVE

We compared the theoretical anatomic feasibility of endovascular treatment of thoracoabdominal aortic aneurysms (TAAAs) with three off-the-shelf multibranched stent-grafts: t-Branch (Zenith t-Branch; Cook Medical, Bloomington, Ind), Gore Excluder thoracoabdominal branch endoprosthesis (TAMBE; W. L. Gore & Associates, Flagstaff, Ariz), and E-nside (E-nside multibranch stent graft system; Jotec GmbH, Hechingen, Germany).

METHODS

Computed tomography scans of patients with degenerative TAAAs treated from 2007 to 2019 were reviewed, and the anatomic feasibility of the multibranched stent-grafts was assessed according to the manufacturer's instructions for use. The anatomic factors determining the overall feasibility were divided into access feasibility, aortic feasibility, and visceral vessel feasibility.

RESULTS

Degenerative TAAAs in 268 patients were analyzed. The overall feasibility did not differ significantly (TAMBE, 33%; t-Branch, 39%; E-nside, 43%; P = .271). Access, aortic, and visceral vessel feasibility alone excluded 18% to 22%, 35% to 49% and 21% to 26% of the patients respectively. The only significant difference between the devices was in aortic feasibility (P = .005), which was more frequently limited by the proximal aortic neck diameter in the TAMBE cohort and the inner visceral aortic diameter in the t-Branch cohort. The overall treatment feasibility using any of the three devices would have been 58%.

CONCLUSIONS

The new investigational off-the-shelf multibranched stent-grafts did not significantly improve the theoretical applicability in an extensive cohort of patients with TAAAs. Improvements are warranted to increase their overall feasibility.

Multi-ancestry GWAS of the electrocardiographic PR interval identifies 202 loci underlying cardiac conduction

The electrocardiographic PR interval reflects atrioventricular conduction, and is associated with conduction abnormalities, pacemaker implantation, atrial fibrillation (AF), and cardiovascular mortality. Here we report a multi-ancestry (N = 293,051) genome-wide association meta-analysis for the PR interval, discovering 202 loci of which 141 have not previously been reported. Variants at identified loci increase the percentage of heritability explained, from 33.5% to 62.6%. We observe enrichment for cardiac muscle developmental/contractile and cytoskeletal genes, highlighting key regulation processes for atrioventricular conduction. Additionally, 8 loci not previously reported harbor genes underlying inherited arrhythmic syndromes and/or cardiomyopathies suggesting a role for these genes in cardiovascular pathology in the general population. We show that polygenic predisposition to PR interval duration is an endophenotype for cardiovascular disease, including distal conduction disease, AF, and atrioventricular pre-excitation. These findings advance our understanding of the polygenic basis of cardiac conduction, and the genetic relationship between PR interval duration and cardiovascular disease.

The genetic study of three population microisolates in South Tyrol (MICROS): study design and epidemiological perspectives

BACKGROUND

There is increasing evidence of the important role that small, isolated populations could play in finding genes involved in the etiology of diseases. For historical and political reasons, South Tyrol, the northern most Italian region, includes several villages of small dimensions which remained isolated over the centuries.

METHODS

The MICROS study is a population-based survey on three small, isolated villages, characterized by: old settlement; small number of founders; high endogamy rates; slow/null population expansion. During the stage-1 (2002/03) genealogical data, screening questionnaires, clinical measurements, blood and urine samples, and DNA were collected for 1175 adult volunteers. Stage-2, concerning trait diagnoses, linkage analysis and association studies, is ongoing. The selection of the traits is being driven by expert clinicians. Preliminary, descriptive statistics were obtained. Power simulations for finding linkage on a quantitative trait locus (QTL) were undertaken.

RESULTS

Starting from participants, genealogies were reconstructed for 50,037 subjects, going back to the early 1600s. Within the last five generations, subjects were clustered in one pedigree of 7049 subjects plus 178 smaller pedigrees (3 to 85 subjects each). A significant probability of familial clustering was assessed for many traits, especially among the cardiovascular, neurological and respiratory traits. Simulations showed that the MICROS pedigree has a substantial power to detect a LOD score > or = 3 when the QTL specific heritability is > or = 20%.

CONCLUSION

The MICROS study is an extensive, ongoing, two-stage survey aimed at characterizing the genetic epidemiology of Mendelian and complex diseases. Our approach, involving different scientific disciplines, is an advantageous strategy to define and to study population isolates. The isolation of the Alpine populations, together with the extensive data collected so far, make the MICROS study a powerful resource for the study of diseases in many fields of medicine. Recent successes and simulation studies give us confidence that our pedigrees can be valuable both in finding new candidates loci and to confirm existing candidate genes.

A meta-analysis of genome-wide data from five European isolates reveals an association of COL22A1, SYT1, and GABRR2 with serum creatinine level

BACKGROUND

Serum creatinine (S CR) is the most important biomarker for a quick and non-invasive assessment of kidney function in population-based surveys. A substantial proportion of the inter-individual variability in S CR level is explicable by genetic factors.

METHODS

We performed a meta-analysis of genome-wide association studies of S CR undertaken in five population isolates ('discovery cohorts'), all of which are part of the European Special Population Network (EUROSPAN) project. Genes showing the strongest evidence for an association with SCR (candidate loci) were replicated in two additional population-based samples ('replication cohorts').

RESULTS

After the discovery meta-analysis, 29 loci were selected for replication. Association between SCR level and polymorphisms in the collagen type XXII alpha 1 (COL22A1) gene, on chromosome 8, and in the synaptotagmin-1 (SYT1) gene, on chromosome 12, were successfully replicated in the replication cohorts (p value = 1.0 x 10(-6) and 1.7 x 10(-4), respectively). Evidence of association was also found for polymorphisms in a locus including the gamma-aminobutyric acid receptor rho-2 (GABRR2) gene and the ubiquitin-conjugating enzyme E2-J1 (UBE2J1) gene (replication p value = 3.6 x 10(-3)). Previously reported findings, associating glomerular filtration rate with SNPs in the uromodulin (UMOD) gene and in the schroom family member 3 (SCHROOM3) gene were also replicated.

CONCLUSIONS

While confirming earlier results, our study provides new insights in the understanding of the genetic basis of serum creatinine regulatory processes. In particular, the association with the genes SYT1 and GABRR2 corroborate previous findings that highlighted a possible role of the neurotransmitters GABAA receptors in the regulation of the glomerular basement membrane and a possible interaction between GABAA receptors and synaptotagmin-I at the podocyte level.

2q37 as a susceptibility locus for idiopathic basal ganglia calcification (IBGC) in a large South Tyrolean family

Familial idiopathic basal ganglia calcification (FIBGC) is an inherited neurodegenerative disorder characterized by the accumulation of calcium deposits in different brain regions, particularly in the basal ganglia. FIBGC usually follows an autosomal dominant pattern of inheritance. Despite the mapping to chromosome 14q of a susceptibility locus for IBGC (IBCG1) in one family, this locus has been excluded in several others, demonstrating genetic heterogeneity in this disorder. The etiology of this disorder thus remains largely unknown. Using a large extended multigenerational Italian family from South Tyrol with 17 affected in a total of 56 members, we performed a genome-wide linkage analysis in which we were able to exclude linkage to the IBCG1 locus on chromosome 14q and obtain evidence of a novel locus on chromosome 2q37. Electronic supplementary material. The online version of this article (doi:10.1007/s12031-009-9287-3) contains supplementary material, which is available to authorized users.

Genetic analyses of the electrocardiographic QT interval and its components identify additional loci and pathways

The QT interval is an electrocardiographic measure representing the sum of ventricular depolarization and repolarization, estimated by QRS duration and JT interval, respectively. QT interval abnormalities are associated with potentially fatal ventricular arrhythmia. Using genome-wide multi-ancestry analyses (>250,000 individuals) we identify 177, 156 and 121 independent loci for QT, JT and QRS, respectively, including a male-specific X-chromosome locus. Using gene-based rare-variant methods, we identify associations with Mendelian disease genes. Enrichments are observed in established pathways for QT and JT, and previously unreported genes indicated in insulin-receptor signalling and cardiac energy metabolism. In contrast for QRS, connective tissue components and processes for cell growth and extracellular matrix interactions are significantly enriched. We demonstrate polygenic risk score associations with atrial fibrillation, conduction disease and sudden cardiac death. Prioritization of druggable genes highlight potential therapeutic targets for arrhythmia. Together, these results substantially advance our understanding of the genetic architecture of ventricular depolarization and repolarization.

Restless legs syndrome: epidemiological and clinicogenetic study in a South Tyrolean population isolate

Genetic contributions to restless legs syndrome (RLS) have been consistently recognized from population and family studies. To determine the clinical and genetic features of RLS in a population isolate and explore linkage to three previously described susceptibility loci on chromosomes 12q, 14q, and 9p, respectively, an isolated population in the South Tyrolean Alps was identified and 530 adults participated in the study. Using a two-step strategy, 47 patients with idiopathic RLS were ascertained. The prevalence in the population was 8.9%. Twenty-eight patients (59.6%) had at least one affected first-degree relative and were classified as hereditary cases. In a single extended pedigree, linkage to known RLS loci was investigated specifying autosomal dominant and recessive models; parametric and nonparametric multipoint linkage scores were computed. None of the calculated linkage scores was suggestive of linkage between RLS and any of the three investigated loci. This study was conducted in a population isolate providing for a homogeneous genetic and environmental background. The absence of a suggestive linkage signal at the three known RLS susceptibility loci is indicative of further locus heterogeneity of this frequent disorder and encourages further studies to unveil the genetic causes of RLS.

A systematic review of infected descending thoracic aortic grafts and endografts

OBJECTIVE

The objective of this study was to collect and critically analyze the current evidence on the modalities and results of treatment of descending thoracic aortic surgical graft (SG) and endograft (EG) infection, which represents a rare but dramatic complication after both surgical and endovascular aortic repair.

METHODS

A comprehensive electronic health database search (PubMed/MEDLINE, Scopus, Google Scholar, and the Cochrane Library) identified all articles that were published up to October 2017 reporting on thoracic aortic SG or EG infection. Observational studies, multicenter reports, single-center series and case reports, case-control studies, and guidelines were considered eligible if reporting specific results of treatment of descending thoracic aortic SG or EG infection. Comparisons of patients presenting with SG or EG infection and between invasive and conservative treatment were performed. Odds ratio (OR) meta-analyses were run when comparative data were available.

RESULTS

Forty-three studies reporting on 233 patients with infected SG (49) or EG (184) were included. Four were multicenter studies including 107 patients, all with EG infection, associated with a fistula in 91% of cases, with a reported overall survival at 2 years of 16% to 39%. The remaining 39 single-center studies included 49 patients with SG infection and 77 with EG infection. Association with aortoesophageal fistula was significantly more common with EG (60% vs 31%; P = .01). In addition, time interval from index procedure to infection was significantly shorter with EG (17 ± 21 months vs 32 ± 61 months; P = .03). Meta-analysis showed a trend of increased 1-year mortality in patients with SG infection compared with EG infection (pooled OR, 3.6; 95% confidence interval, 0.9-14.7; P = .073). Surgical management with infected graft explantation was associated with a trend toward lower 1-year mortality compared with graft preservation (pooled OR, 0.3; 95% confidence interval, 0.1-1.0; P = .056).

CONCLUSIONS

Thoracic aortic EG infection is likely to occur more frequently in association with aortoesophageal fistulas and in a shorter time compared with SG infection. Survival is poor in both groups, especially in patients with SG infection. Surgical treatment with graft explantation seems to be the preferable choice in fit patients.

Effects of Calcium, Magnesium, and Potassium Concentrations on Ventricular Repolarization in Unselected Individuals

BACKGROUND

Subclinical changes on the electrocardiogram are risk factors for cardiovascular mortality. Recognition and knowledge of electrolyte associations in cardiac electrophysiology are based on only in vitro models and observations in patients with severe medical conditions.

OBJECTIVES

This study sought to investigate associations between serum electrolyte concentrations and changes in cardiac electrophysiology in the general population.

METHODS

Summary results collected from 153,014 individuals (54.4% women; mean age 55.1 ± 12.1 years) from 33 studies (of 5 ancestries) were meta-analyzed. Linear regression analyses examining associations between electrolyte concentrations (mmol/l of calcium, potassium, sodium, and magnesium), and electrocardiographic intervals (RR, QT, QRS, JT, and PR intervals) were performed. The study adjusted for potential confounders and also stratified by ancestry, sex, and use of antihypertensive drugs.

RESULTS

Lower calcium was associated with longer QT intervals (-11.5 ms; 99.75% confidence interval [CI]: -13.7 to -9.3) and JT duration, with sex-specific effects. In contrast, higher magnesium was associated with longer QT intervals (7.2 ms; 99.75% CI: 1.3 to 13.1) and JT. Lower potassium was associated with longer QT intervals (-2.8 ms; 99.75% CI: -3.5 to -2.0), JT, QRS, and PR durations, but all potassium associations were driven by use of antihypertensive drugs. No physiologically relevant associations were observed for sodium or RR intervals.

CONCLUSIONS

The study identified physiologically relevant associations between electrolytes and electrocardiographic intervals in a large-scale analysis combining cohorts from different settings. The results provide insights for further cardiac electrophysiology research and could potentially influence clinical practice, especially the association between calcium and QT duration, by which calcium levels at the bottom 2% of the population distribution led to clinically relevant QT prolongation by >5 ms.

H- desorption from uracil via metastable electron capture

In this Letter we report an analysis of the quantum dynamics for the scattering of slow electrons off uracil molecules, leading to the formation of a trapped, metastable anionic state at around 9 eV of energy. This resonant state is seen to be capable of describing an anionic molecular precursor which can explain the desorption of the H- species observed in experiments on film deposited uracil samples.

Reducing the environmental impact of surgery on a global scale: systematic review and co-prioritization with healthcare workers in 132 countries

BACKGROUND

Healthcare cannot achieve net-zero carbon without addressing operating theatres. The aim of this study was to prioritize feasible interventions to reduce the environmental impact of operating theatres.

METHODS

This study adopted a four-phase Delphi consensus co-prioritization methodology. In phase 1, a systematic review of published interventions and global consultation of perioperative healthcare professionals were used to longlist interventions. In phase 2, iterative thematic analysis consolidated comparable interventions into a shortlist. In phase 3, the shortlist was co-prioritized based on patient and clinician views on acceptability, feasibility, and safety. In phase 4, ranked lists of interventions were presented by their relevance to high-income countries and low-middle-income countries.

RESULTS

In phase 1, 43 interventions were identified, which had low uptake in practice according to 3042 professionals globally. In phase 2, a shortlist of 15 intervention domains was generated. In phase 3, interventions were deemed acceptable for more than 90 per cent of patients except for reducing general anaesthesia (84 per cent) and re-sterilization of 'single-use' consumables (86 per cent). In phase 4, the top three shortlisted interventions for high-income countries were: introducing recycling; reducing use of anaesthetic gases; and appropriate clinical waste processing. In phase 4, the top three shortlisted interventions for low-middle-income countries were: introducing reusable surgical devices; reducing use of consumables; and reducing the use of general anaesthesia.

CONCLUSION

This is a step toward environmentally sustainable operating environments with actionable interventions applicable to both high- and low-middle-income countries.

Echocardiographic features of hypertensive-diabetic heart muscle disease

Computerized M-mode echocardiography was used to evaluate left ventricular anatomy and function in 20 patients with hypertension and diabetes mellitus, without signs of overt heart disease. A similar study was performed in 20 patients with hypertension of similar severity and duration and in 20 normal subjects. Mean posterior wall thickness and mean septal thickness were increased in hypertensive patients compared to normal (p less than 0.001), but diabetic patients had thicker septa with respect to nondiabetics (p less than 0.05). All hypertensive-diabetic patients had reduced peak lengthening rate and/or peak velocity of posterior wall thinning. Six of them also had reduced peak Vcf and/or peak velocity of posterior wall thickening. Only 9 of the 20 patients with hypertension alone had abnormal diastolic function; 4 out of these 9 also had abnormal systolic function. We conclude that diabetes causes more severe impairment of left ventricular function in patients with a similar degree of hypertension. The more consistent abnormalities are reduced rate of dimension increase during filling and slower wall thinning, suggesting impaired left ventricular relaxation and distensibility.

Anatomic feasibility of the investigational GORE EXCLUDER Thoracoabdominal Branch Endoprosthesis (TAMBE), off-the-shelf multibranched endograft for the treatment of pararenal and thoracoabdominal aortic aneurysms

OBJECTIVE

The objective of this study was to evaluate the proportion of pararenal aortic aneurysms and thoracoabdominal aortic aneurysms (TAAAs) that could theoretically be treated with the investigational GORE EXCLUDER Thoracoabdominal Branch Endoprosthesis (TAMBE; W. L. Gore & Associates, Flagstaff, Ariz) off-the-shelf multibranched endograft.

METHODS

The preoperative computed tomography scans of patients with pararenal aortic aneurysms and TAAAs treated at a single institution between 2007 and 2017 were reviewed. This cohort included both open and endovascular repairs performed in either elective or urgent/emergent settings. These studies were included in a retrospective feasibility study to verify anatomic feasibility of the TAMBE graft (with four antegrade portals) employed within the manufacturer's investigational instructions for use during the U.S. pivotal trial. The patient cohort was divided into two groups: extended thoracoabdominal aneurysm (E-TAA)-extent I, II, and III TAAA; and limited pararenal and thoracoabdominal aneurysm (L-TAA)-pararenal aortic aneurysm and extent IV TAAA. The anatomic factors determining the overall theoretical feasibility were further divided into three groups: vascular access feasibility, aortic feasibility, and visceral vessel feasibility.

RESULTS

Computed tomography scans of 227 patients with degenerative aneurysms were analyzed, 166 with E-TAA and 61 with L-TAA. In the L-TAA group, 49% of the cases could have been treated with the TAMBE endograft alone; access feasibility was 85%, aortic feasibility 74%, and visceral vessel feasibility 72%. In the E-TAA group, only 23% of the cases could have been treated with a TAMBE combined with a GORE CTAG proximal thoracic stent graft; access feasibility was 79%, aortic feasibility 48%, and visceral vessel feasibility 63%. The different feasibility rate was related to a difference in aortic feasibility between L-TAA and E-TAA (74% vs 48%; P = .0008) because of the lack of a dedicated tapered thoracic component.

CONCLUSIONS

The TAMBE multibranched endograft can theoretically be employed in half of an all-comers cohort of patients with degenerative L-TAA. Development of a dedicated tapered thoracic component is warranted to increase the feasibility for E-TAA, and comparative studies are required to investigate differences with other available off-the-shelf stent grafts.

Ten years of dynamic consent in the CHRIS study: informed consent as a dynamic process

The Cooperative Health Research in South Tyrol (CHRIS) is a longitudinal study in Northern Italy, using dynamic consent since its inception in 2011. The CHRIS study collects health data and biosamples for research, and foresees regular follow-ups over time. We describe the experience with the CHRIS study dynamic consent, providing an overview of its conceptualization and implementation, and of the participant-centered strategies used to assess and improve the process, directly linked to participation and communication. In order to comply with high ethical standards and to allow broadness in the areas of research, CHRIS dynamic consent was conceived as an interactive process: based on a strong governance and an ongoing tailored communication with participants, it aims to promote autonomy and to develop a trust-based engaged relationship with participants, also relevant for retention. Built within an online platform, the consent allows granular choices, which can be changed over time. In a process of co-production, participants views have been investigated and kept into account in policy development. Participants showed a high degree of participation, thus enabling the consolidation of the CHRIS resources. Even though a low change rate was reported in the baseline, participants valued the possibility of changing their informed consent choices. Communication (language-tailored, ongoing, multimedia) was important for participants, and for participation and retention. In our experience, dynamic consent was proven to be a flexible consent model, which allowed to meet ethical and legal standards for participation in research, and to accommodate participants' and researchers' needs.

Differential and shared genetic effects on kidney function between diabetic and non-diabetic individuals

Reduced glomerular filtration rate (GFR) can progress to kidney failure. Risk factors include genetics and diabetes mellitus (DM), but little is known about their interaction. We conducted genome-wide association meta-analyses for estimated GFR based on serum creatinine (eGFR), separately for individuals with or without DM (nDM = 178,691, nnoDM = 1,296,113). Our genome-wide searches identified (i) seven eGFR loci with significant DM/noDM-difference, (ii) four additional novel loci with suggestive difference and (iii) 28 further novel loci (including CUBN) by allowing for potential difference. GWAS on eGFR among DM individuals identified 2 known and 27 potentially responsible loci for diabetic kidney disease. Gene prioritization highlighted 18 genes that may inform reno-protective drug development. We highlight the existence of DM-only and noDM-only effects, which can inform about the target group, if respective genes are advanced as drug targets. Largely shared effects suggest that most drug interventions to alter eGFR should be effective in DM and noDM.

Outcomes of routine use of percutaneous access with large-bore introducer sheaths (>21F outer diameter) during endovascular aneurysm repair

OBJECTIVE

The objective of this study was to evaluate the performance of percutaneous femoral access with large-bore sheaths (>21F outer diameter) mainly employed for thoracic and thoracoabdominal aortic endovascular treatment and to stratify the outcomes on the basis of the introducer size.

METHODS

Between December 2015 and December 2018, all consecutive patients who received endovascular repair through a percutaneous approach with a suture-mediated vascular closure device (VCD) and the preclose technique were included in a retrospective single-center study called Totally Percutaneous Approach to Endovascular Treatment of Aortic Aneurysms (PEVAR-PRO). The morphologic characteristics of the access vessels and patients' demographics were recorded, and 30-day closure success was defined as the primary end point. Analysis of the closure success comparing large-bore sheaths vs small-bore sheaths (≤21F outer diameter) was performed after 1:1 propensity score matching of preoperative confounding variables.

RESULTS

The closure success rate of the entire study cohort was 94% (622 femoral accesses in 360 patients; median age, 74 years; 84% male). Univariate analysis identified eight different factors associated with failure, but only two remained significant on multivariate analysis: diabetes (odds ratio [OR], 2.8; 95% confidence interval [CI], 1.3-6.2; P = .011) and common femoral artery stenosis >50% (OR, 4.5; 95% CI, 1.3-13.7; P = .019). After propensity score matching (1:1, 172 femoral accesses per group), closure success rate was not significantly different between large-bore and small-bore sheaths (90.7% vs 93.0%; P = .43). Multivariate analysis of the large-sheath group identified two factors associated with failure: small (<9 mm) femoral arteries (OR, 6.9; 95% CI, 1.5-31.6; P = .13) and access vessel calcifications involving more than one-third of the circumference (OR, 7.9; 95% CI, 2.1-29.4; P = .002). Neither previous femoral cutdown (44 accesses [23%]) nor percutaneous closure with VCDs (38 accesses [20%]) affected the closure success rate in the large-sheath group. Closure failure did not significantly increase the need for postoperative blood transfusions or hospital length of stay.

CONCLUSIONS

Off-label use of VCDs and the preclose technique for percutaneous approach with large-bore sheaths needed for complex aortic endovascular procedures is safe and feasible. Closure success rate is not significantly different from that obtained with on-label application of VCDs with smaller sheaths.

How to best treat infectious complications of open and endovascular thoracic aortic repairs

Infectious complications of open and endovascular procedures for descending thoracic aortic disease are relatively rare, affecting 1% to 6% of treated patients. However, the number of thoracic aortic procedures, especially endovascular, is increasing continuously, and infectious complications involving the graft or endograft have been observed more frequently in recent years. Several causative factors may play a role in thoracic aortic prosthetic infections, including hematogenous seeding, local bacterial translocation, and iatrogenous contamination. In addition, the development of a fistula between the aortic graft and the esophagus or the bronchial tree is a common associated finding, representing a dramatic event that further increases mortality rates and requires multidisciplinary management. Treatment of these conditions is demanding, often including a number of pharmacological, surgical, and endovascular options. Because there are several different surgical strategies and timing modalities that are chosen according to the surgeon's experience, the results of different treatment options are difficult to summarize, and no consensus exists on a standardized paradigm of treatment. In this review, published reports regarding clinical outcomes related to thoracic graft and endograft infections are discussed, including our personal experience with surgical and endovascular management of this condition.

Sequential recruitment of study participants may inflate genetic heritability estimates

After the success of genome-wide association studies to uncover complex trait loci, attempts to explain the remaining genetic heritability (h ²) are mainly focused on unraveling rare variant associations and gene-gene or gene-environment interactions. Little attention is paid to the possibility that h ² estimates are inflated as a consequence of the epidemiological study design. We studied the time series of 54 biochemical traits in 4373 individuals from the Cooperative Health Research In South Tyrol (CHRIS) study, a pedigree-based study enrolling ten participants/day over several years, with close relatives preferentially invited within the same day. We observed distributional changes of measured traits over time. We hypothesized that the combination of such changes with the pedigree structure might generate a shared-environment component with consequent h ² inflation. We performed variance components (VC) h ² estimation for all traits after accounting for the enrollment period in a linear mixed model (two-stage approach). Accounting for the enrollment period caused a median h ² reduction of 4%. For 9 traits, the reduction was of >20%. Results were confirmed by a Bayesian Markov chain Monte Carlo analysis with all VCs included at the same time (one-stage approach). The electrolytes were the traits most affected by the enrollment period. The h ² inflation was independent of the h ² magnitude, laboratory protocol changes, and length of the enrollment period. The enrollment process may induce shared-environment effects even under very stringent and standardized operating procedures, causing h ² inflation. Including the day of participation as a random effect is a sensitive way to avoid overestimation.

Open or endovascular treatment of downstream thoracic or thoraco-abdominal aortic pathology after frozen elephant trunk: perioperative and mid-term outcomes

OBJECTIVES

The aim of this study was to evaluate the outcomes of open and endovascular treatment of downstream thoracic or thoraco-abdominal aortic pathology in patients who underwent previous frozen elephant trunk (FET).

METHODS

Data were retrieved to evaluate mortality, cardiac, pulmonary, cerebrovascular, renal and spinal cord major adverse events, early- and mid-term reintervention and survival rates. The Society for Vascular Surgery endovascular reporting standards were used.

RESULTS

From 2011 to 2020, 48 patients (36 males, median age 60 years) underwent downstream aortic repair at a median of 18 months (interquartile range: 6-57) after the initial FET. Twenty-eight patients (58.3%) received open and 20 (41.7%) endovascular repair. The overall 30-day mortality was 6.3% and the initial clinical success was 88%, with no inter-group differences (P = 0.22 and 0.66 respectively). Six spinal cord deficits were recorded (13%): 3 (6.3%) were permanent. The major adverse events incidence was lower in the endovascular cohort [4 (20%) vs 14 (50%); P = 0.047], mainly due to a lower rate of grade ≥2 respiratory complications (5% vs 42.9%; P = 0.004). Assisted primary clinical success at 5 years was higher in the endovascular group (95% vs 68%, P = 0.022); freedom from reintervention at competing risk analysis (P = 0.3) and overall survival at Kaplan-Meier curves (log-rank P = 0.29) were similar.

CONCLUSIONS

Downstream aortic repair after FET is feasible with both open and endovascular repair with acceptable mortality and permanent paraplegia rates. The endovascular approach has potential perioperative and mid-term advantages, but long-term durability has to be further investigated in larger cohorts.