Admixture mapping of peripheral artery disease in a Dominican population reveals a putative risk locus on 2q35.

Peripheral artery disease (PAD) is a form of atherosclerotic cardiovascular disease, affecting ∼8 million Americans, and is known to have racial and ethnic disparities. PAD has been reported to have a significantly higher prevalence in African Americans (AAs) compared to non-Hispanic European Americans (EAs). Hispanic/Latinos (HLs) have been reported to have lower or similar rates of PAD compared to EAs, despite having a paradoxically high burden of PAD risk factors; however, recent work suggests prevalence may differ between sub-groups. Here, we examined a large cohort of diverse adults in the BioMe biobank in New York City. We observed the prevalence of PAD at 1.7% in EAs vs. 8.5% and 9.4% in AAs and HLs, respectively, and among HL sub-groups, the prevalence was found at 11.4% and 11.5% in Puerto Rican and Dominican populations, respectively. Follow-up analysis that adjusted for common risk factors demonstrated that Dominicans had the highest increased risk for PAD relative to EAs [OR = 3.15 (95% CI 2.33-4.25), p < 6.44 × 10-14]. To investigate whether genetic factors may explain this increased risk, we performed admixture mapping by testing the association between local ancestry and PAD in Dominican BioMe participants (N = 1,813) separately from European, African, and Native American (NAT) continental ancestry tracts. The top association with PAD was an NAT ancestry tract at chromosome 2q35 [OR = 1.96 (SE = 0.16), p < 2.75 × 10-05) with 22.6% vs. 12.9% PAD prevalence in heterozygous NAT tract carriers versus non-carriers, respectively. Fine-mapping at this locus implicated tag SNP rs78529201 located within a long intergenic non-coding RNA (lincRNA) LINC00607, a gene expression regulator of key genes related to thrombosis and extracellular remodeling of endothelial cells, suggesting a putative link of the 2q35 locus to PAD etiology. Efforts to reproduce the signal in other Hispanic cohorts were unsuccessful. In summary, we showed how leveraging health system data helped understand nuances of PAD risk across HL sub-groups and admixture mapping approaches elucidated a putative risk locus in a Dominican population.

Admixture Mapping of Peripheral Artery Disease in a Dominican Population Reveals a Novel Risk Locus on 2q35.

Peripheral artery disease (PAD) is a form of atherosclerotic cardiovascular disease, affecting ∼8 million Americans, and is known to have racial and ethnic disparities. PAD has been reported to have significantly higher prevalence in African Americans (AAs) compared to non-Hispanic European Americans (EAs). Hispanic/Latinos (HLs) have been reported to have lower or similar rates of PAD compared to EAs, despite having a paradoxically high burden of PAD risk factors, however recent work suggests prevalence may differ between sub-groups. Here we examined a large cohort of diverse adults in the Bio Me biobank in New York City (NYC). We observed the prevalence of PAD at 1.7% in EAs vs 8.5% and 9.4% in AAs and HLs, respectively; and among HL sub-groups, at 11.4% and 11.5% in Puerto Rican and Dominican populations, respectively. Follow-up analysis that adjusted for common risk factors demonstrated that Dominicans had the highest increased risk for PAD relative to EAs (OR=3.15 (95% CI 2.33-4.25), P <6.44×10 -14 ). To investigate whether genetic factors may explain this increased risk, we performed admixture mapping by testing the association between local ancestry (LA) and PAD in Dominican Bio Me participants (N=1,940) separately for European (EUR), African (AFR) and Native American (NAT) continental ancestry tracts. We identified a NAT ancestry tract at chromosome 2q35 that was significantly associated with PAD (OR=2.05 (95% CI 1.51-2.78), P <4.06×10 -6 ) with 22.5% vs 12.5% PAD prevalence in heterozygous NAT tract carriers versus non-carriers, respectively. Fine-mapping at this locus implicated tag SNP rs78529201 located within a long intergenic non-coding RNA (lincRNA) LINC00607 , a gene expression regulator of key genes related to thrombosis and extracellular remodeling of endothelial cells, suggesting a putative link of the 2q35 locus to PAD etiology. In summary, we showed how leveraging health systems data helped understand nuances of PAD risk across HL sub-groups and admixture mapping approaches elucidated a novel risk locus in a Dominican population.

Metabolite patterns associated with individual response to supervised exercise therapy in patients with intermittent claudication.

Objective: Supervised exercise therapy (SET) is the first line treatment for intermittent claudication owing to peripheral arterial disease. Despite multiple randomized controlled trials proving the efficacy of SET, there are large differences in individual patient's responses. We used plasma metabolomics to identify potential metabolic influences on the individual response to SET. Methods: Primary metabolites, complex lipids, and lipid mediators were measured on plasma samples taken at before and after Gardner graded treadmill walking tests that were administered before and after 12 weeks of SET. We used an ensemble modeling approach to identify metabolites or changes in metabolites at specific time points that associated with interindividual variability in the functional response to SET. Specific time points analyzed included baseline metabolite levels before SET, dynamic metabolomics changes before SET, the difference in pre- and post-SET baseline metabolomics, and the difference (pre- and post-SET) of the dynamic (pre- and post-treadmill). Results: High levels of baseline anandamide levels pre- and post-SET were associated with a worse response to SET. Increased arachidonic acid (AA) and decreased levels of the AA precursor dihomo-γ-linolenic acid across SET were associated with a worse response to SET. Participants who were able to tolerate large increases in AA during acute exercise had longer, or better, walking times both before and after SET. Conclusions: We identified two pathways of relevance to individual response to SET that warrant further study: anandamide synthesis may activate endocannabinoid receptors, resulting in worse treadmill test performance. SET may train patients to withstand higher levels of AA, and inflammatory signaling, resulting in longer walking times. Clinical Relevance: This manuscript describes the use of metabolomic techniques to measure the interindividual effects of SET in patients with peripheral artery disease (PAD). We identified high levels of AEA are linked to CB1 signaling and activation of inflammatory pathways. This alters energy expenditure in myoblasts by decreasing glucose uptake and may induce an acquired skeletal muscle myopathy. SET may also help participants tolerate increased levels of AA and inflammation produced during exercise, resulting in longer walking times. This data will enhance understanding of the pathophysiology of PAD and the mechanism by which SET improves walking intolerance.

Performance of polygenic risk scores for cancer prediction in a racially diverse academic biobank.

PURPOSE: Genome-wide association studies have identified hundreds of single nucleotide variations (formerly single nucleotide polymorphisms) associated with several cancers, but the predictive ability of polygenic risk scores (PRSs) is unclear, especially among non-Whites. METHODS: PRSs were derived from genome-wide significant single-nucleotide variations for 15 cancers in 20,079 individuals in an academic biobank. We evaluated the improvement in discriminatory accuracy by including cancer-specific PRS in patients of genetically-determined African and European ancestry. RESULTS: Among the individuals of European genetic ancestry, PRSs for breast, colon, melanoma, and prostate were significantly associated with their respective cancers. Among the individuals of African genetic ancestry, PRSs for breast, colon, prostate, and thyroid were significantly associated with their respective cancers. The area under the curve of the model consisting of age, sex, and principal components was 0.621 to 0.710, and it increased by 1% to 4% with the inclusion of PRS in individuals of European genetic ancestry. In individuals of African genetic ancestry, area under the curve was overall higher in the model without the PRS (0.723-0.810) but increased by <1% with the inclusion of PRS for most cancers. CONCLUSION: PRS moderately increased the ability to discriminate the cancer status in individuals of European but not African ancestry. Further large-scale studies are needed to identify ancestry-specific genetic factors in non-White populations to incorporate PRS into cancer risk assessment.

Length of Stay after Thoracic Endovascular Aortic Repair Depends on Indication and Acuity.

BACKGROUND: Length of stay (LOS) is a commonly used metric to optimize value in medical care. Although pathways have been developed for some procedures in vascular surgery to reduce LOS, they do not yet exist for thoracic endovascular aortic repair (TEVAR). The purpose of this study is to identify and define the risk factors for prolonged LOS in patients undergoing TEVAR to facilitate pathway development. METHODS: We included TEVAR patients in the National Surgical Quality Improvement Program database from 2005 to 2015. Prolonged LOS was defined as LOS > 75th percentile of the overall cohort (11 days). Because initial analysis revealed the distinct clinical differences between dissection and aneurysm patients, further analysis was stratified by aortic pathology. Student's t-test and Chi-square tests were used to compare demographic and perioperative variables between dissection and aneurysm patients, respectively. Multivariable logistic regression was used to evaluate the predictors for prolonged LOS. RESULTS: A total of 3,021 patients underwent TEVAR, with 858 patients (28.4%) undergoing TEVAR for dissection and 2,163 (71.6%) undergoing TEVAR for aneurysm. An initial analysis with logistic regression identified dissection indication (odds ratio [OR], 2.87; 95% confidence interval [CI], 1.1-7.3) as an independent predictor of prolonged LOS. Further analysis for prolonged LOS was subsequently performed separating dissection and aneurysm patients. Aneurysm patients were older (71.2 ± 11.7 vs. 63.1 ± 13.6 years, P < 0.001), more often Caucasian (76.8% vs. 61.8%, P < 0.001), and had more medical comorbidities (chronic obstructive pulmonary disease, cardiac history, diabetes, peripheral vascular disease, transient ischemic attack [TIA], P < 0.001). In contrast, dissection patients had higher American Society of Anesthesiology (ASA) classification score (58.5% had >3 ASA vs. 45.5%, P < 0.001), longer hospitalizations (10.2 ± 9.3 vs. 8.5 ± 10.4 days, P < 0.001), were more likely to have been transferred from another hospital or emergency room (58.4% vs. 48.3%, P < 0.001), and were more often emergent (32.4% vs. 15.4%, P < 0.001). In dissection patients, ASA classification score (OR, 1.49; 95% CI, 1.1-2.1) and dialysis (OR, 1.98; 95% CI, 1.0-3.9) were independent predictors for prolonged LOS. In aneurysm patients, dependent functional status (OR, 2.03; 95% CI, 1.4-2.8), diabetes (OR, 1.75; 95% CI, 1.1-2.8), cardiac history (OR, 1.37; 95% CI, 1.0-1.9), emergency status (OR, 1.98; 95% CI, 1.4-2.8), and dialysis (OR, 2.08; 95% CI, 1.2-3.7) predicted prolonged LOS. Postoperative complications including stroke/TIA; failure to wean from ventilator, sepsis, and pneumonia; and need for reoperation similarly increased LOS in both dissection and aneurysm patients. CONCLUSIONS: Dissection and aneurysm patients undergoing TEVAR are comprised of different patient populations, with dissection patients more often enduring prolonged hospitalizations. In contrast, TEVAR performed for nonemergent aneurysm repair had the shortest LOS. These data support the development of separate pathways defined by indication and acuity for patients undergoing TEVAR.

Impact of acute postoperative limb ischemia after cardiac and thoracic aortic surgery.

OBJECTIVE: Acute limb ischemia (ALI) is the cause of significant morbidity and mortality. Although ALI after cardiac surgery is associated with high rates of morbidity and mortality, there are no robust, controlled analyses of the risk factors and outcomes of ALI in this setting. We aimed to identify risk factors for and to delineate outcomes after ALI in patients undergoing cardiac surgery. METHODS: We performed a retrospective review of prospectively collected data on patients undergoing cardiac surgery at our institution between 2002 and 2012. RESULTS: Between 2002 and 2012, there were 11,343 patients who underwent major open cardiac surgery, with 156 cases of ALI for an incidence of 1.4%. In a multivariable model, significant risk factors for ALI included body surface area (odds ratio [OR], 0.41; 95% confidence interval [CI], 0.18-0.92), current smoking status (OR, 2.2; 95% CI, 1.3-3.7), peripheral arterial disease (OR, 2.5; 95% CI, 1.6-3.7), nonelective operative status (OR, 1.9-5.0; 95% CI, 1.2-19.7), use of extracorporeal membrane oxygenation (OR, 5.6; 95% CI, 2.5-11.6) or intra-aortic balloon pump (OR, 4.7; 95% CI, 2.9-7.5), and valve operation (OR, 2.1; 95% CI, 1.1-4.0). There were 105 (67%) patients who developed ALI who required an operation, and 27 (17%) required an amputation on the index admission. ALI was associated with a significant reduction in long-term survival (hazard ratio, 3.72; 95% CI, 2.97-4.65; P < .0001). CONCLUSIONS: ALI is associated with significant morbidity and mortality, and it is also associated with reduced long-term survival. Those patients with the risk factors described require extra vigilance to limit the risk of ALI and should be managed in accordance with the patient's overall clinical condition and goals of care.

The role of body mass index class in cholecystectomy after acute cholecystitis: An American College of Surgeons National Surgical Quality Improvement Program analysis.

BACKGROUND: Obesity is a risk factor for cholelithiasis leading to acute cholecystitis which is treated with cholecystectomy. The purpose of this study was to analyze the associations between body mass index class and the intended operative approach (laparoscopic versus open) for and outcomes of cholecystectomy for acute cholecystitis. METHODS: We conducted a retrospective cohort study using the American College of Surgeons National Surgical Quality Improvement Program data from 2008-2013. The effects of body mass index class on intended procedure type (laparoscopic versus open), conversion from laparoscopic to open operation, and outcomes after cholecystectomy were examined using multivariable logistic regression. RESULTS: Data on 20,979 patients who underwent cholecystectomy for acute cholecystitis showed that 18,228 (87%) had a laparoscopic operation; 639 (4%) of these patients required conversion to an open approach; and 2,751 (13%) underwent intended open cholecystectomy. There was an independent association between super obesity (body mass index 50+) and an intended open operation (odds ratio 1.53, 95% confidence interval 1.14-2.05, P = .01). An intended open procedure (odds ratio 3.10, 95% confidence interval 2.40-4.02, P < .0001) and conversion (odds ratio 3.45, 95% confidence interval 2.16-5.50, P < .0001) were associated with increased risk of death/serious morbidity in a model, even when controlling for all other important factors. In the same model, body mass index class was not associated with increased death/serious morbidity. Outcomes after conversion were not substantially worse than outcomes after intended open cholecystectomy. CONCLUSION: This study supports the possibility that an intended open approach to acute cholecystitis, not body mass index class, is associated with worse outcomes after cholecystectomy. An initial attempt at laparoscopy may benefit patients, even those at the highest end of the body mass index spectrum.