Contemporary outcomes for branch renal artery repair.

BACKGROUND: The purpose of this study was to provide an updated description of demographics, technical details, and clinical outcomes of 101 consecutive branch renal artery repairs in 98 patients using cold perfusion. METHODS: A single-institution, retrospective analysis branch renal artery reconstructions was performed between 1987 and 2019. RESULTS: Patients were predominantly Caucasian (80.6%) women (74.5%) with a mean age of 46.8 ± 15.3 years. The mean preoperative systolic and diastolic blood pressures were 170.4 ± 33.0 mm Hg and 99.2 ± 19.9 mm Hg, respectively, requiring a mean of 1.6 ± 1.1 antihypertensive medications. The estimated glomerular filtration rate was 84.0 ± 25.3 mL/min. Most patients (90.2%) were not diabetic and never smokers (68%). Treated pathology included aneurysm (87.4%) and stenosis (23.3%) with histology demonstrating fibromuscular dysplasia (44.4%), dissection (5.1%), and degenerative not otherwise specified (50.5%). The right renal arteries were most frequently treated (44.2%), with a mean of 3.1 ± 1.5 branches involved. Reconstruction was accomplished using bypass in 90.3% of cases using aortic inflow in 92.7% and a saphenous vein conduit in 92%. Branch vessels served as outflow in 96.9% and syndactylization of branches was used to decrease the number of distal anastomoses in 45.3% of repairs. The mean number of distal anastomoses was 1.5 ± 0.9. Postoperatively, the mean systolic blood pressure improved to 137.9 ± 20.8 mm Hg (mean decrease of 30.5 ± 32.8 mm Hg; P < .0001) and the mean diastolic blood pressure improved to 78.4 ± 12.7 mm Hg (mean decrease of 20.1 ± 20.7 mm Hg; P < .0001) with patients requiring a mean of 1.4 ± 1.0 antihypertensive medications (mean decrease of 0.2 ±1.0 medications; P = .048). The postoperative estimated glomerular filtration rate was 89.1 mL/min (mean increase of 4.1 mL/min; P = .08). The mean length of stay was 9.0 ± 5.8 days and 96.1% of patients were discharged home. The mortality rate was 1% (one patient with liver failure) and the major morbidity rate was 15%. There were five infectious complications (pneumonia, Clostridium difficile, and wound infection) and five patients required return to the operating room (one for nephrectomy, one for bleeding, two for thrombosis, and one for second trimester pregnancy loss requiring dilation and curettage and splenectomy). One patient required temporary dialysis owing to graft thrombosis. Two patients developed arrhythmias. No patients suffered a myocardial infarction, stroke, or limb loss. After 30 days, follow-up data were available for 82 bypasses. At this time, three reconstructions were no longer patent. Intervention was required to retain patency for five bypasses. After 1 year, patency data were available for 61 bypasses and five were no longer patent. Of the five grafts with loss of patency, two underwent intervention in attempt to maintain patency, which subsequently failed. CONCLUSIONS: Repair of renal artery pathology involving the branches can be performed with short- and long-term technical success and significant prospect of decreasing an elevated blood pressure. The operations required to fully address the presenting pathology are often quite complex involving multiple distal anastomoses and consolidation of small secondary branches. The procedure carries a small but significant risk of major morbidity and mortality.

A Single-Center Experience with Forearm Arteriovenous Loop Grafts for Hemodialysis.

BACKGROUND: Autogenous arteriovenous fistula (AVF) remains the standard of hemodialysis (HD) access; however, it cannot be reasonably obtained in all patients. For patients with contraindications to AVFs, prosthetic arteriovenous graft (AVG) remains an alternative. AVGs are plagued by high failure rates; however, there is a paucity of literature examining this. This study aims to examine a single-center review of outcomes of forearm loop AVGs in patients requiring HD access. METHODS: A single institution, retrospective chart review was completed from 2012 to 2019, including demographics, end-stage renal disease etiology, brachial vessel diameters, and comorbidities. Logistic regression and Cox proportional hazard models were evaluated. Outcomes were defined as primary patency (time elapsed from graft creation until it was utilized as the patient's primary access), primary-assisted patency (time from primary access to intervention to maintain patency), and functional patency (time from graft placement until graft failure). Additionally, multinomial regression models were used to evaluate associations with categorical number of required interventions. RESULTS: Ninety-eight patients [mean age 61.8 (13.9) years, 42.9% female] were identified as having brachial artery to brachial vein AVG creation during the study period, of which 75% achieved primary patency. Primary-assisted patency was 0.36 [standard error (SE) 0.07] at 6 months and 0.12 (SE 0.05) at 1 year. Functional patency was 0.75 (SE 0.07) at 6 months and 0.43 (SE 0.09) at 1 year. No association between preoperative vessel diameters and primary-assisted or functional patency was observed. Interestingly, there was a significant negative association between previous ipsilateral access and achievement of primary patency with a 60% decrease in odds of achieving primary patency in patients with previous ipsilateral access [odds ratio 0.4, 95% confidence interval (CI) 0.1-0.9, P = 0.03]. There was also noted to be a significant association between the presence of an ipsilateral catheter and increased risk of subsequent abandonment of the AVG (hazard ratio 2.6, 95% CI 1.1-5.8, P = 0.02). CONCLUSIONS: Prosthetic forearm loop AVGs remain hindered in their utility as they show high rates of graft failure within a year of creation. A significant patient-specific factor leading to this was not clearly demonstrated. As guidelines change regarding the nature of dialysis access for patients on HD, these results draw into question the utility of prosthetic forearm loop grafts in patients requiring long-term HD access.

Unique Case of Neurogenic Thoracic Outlet Syndrome with Arterial Compression in Patient with Bilateral Cervical Ribs and Osteochondroma of the Ribs.

Background: Neurogenic thoracic outlet syndrome typically presents with paresthesia, pain, and impaired strength in the neck, shoulder, and arm, and is typically a diagnosis of exclusion. This condition is caused by compression of the brachial plexus, typically by a bony or soft tissue anomaly present congenitally and influenced by repetitive motion or significant trauma. Treatment typically involves removal of the first rib and anterior scalene to decompress the thoracic outlet and relieve stress to the brachial plexus if the patient has failed conservative treatment with physical therapy and lifestyle modifications. Case Presentation: We present a case of neurogenic thoracic outlet syndrome with arterial compression treated surgically via a transaxillary first rib and cervical rib resection in a patient with bilateral cervical ribs and osteochondromas of the ribs.

Identification of an ATP/P2X7/mast cell pathway mediating ozone-induced bronchial hyperresponsiveness.

Ozone is a highly reactive environmental pollutant with well-recognized adverse effects on lung health. Bronchial hyperresponsiveness (BHR) is one consequence of ozone exposure, particularly for individuals with underlying lung disease. Our data demonstrated that ozone induced substantial ATP release from human airway epithelia in vitro and into the airways of mice in vivo and that ATP served as a potent inducer of mast cell degranulation and BHR, acting through P2X7 receptors on mast cells. Both mast cell-deficient and P2X7 receptor-deficient (P2X7-/-) mice demonstrated markedly attenuated BHR to ozone. Reconstitution of mast cell-deficient mice with WT mast cells and P2X7-/- mast cells restored ozone-induced BHR. Despite equal numbers of mast cells in reconstituted mouse lungs, mice reconstituted with P2X7-/- mast cells demonstrated significantly less robust BHR than mice reconstituted with WT mast cells. These results support a model where P2X7 on mast cells and other cell types contribute to ozone-induced BHR.

Circadian rhythms vary over the growing season and correlate with fitness components.

Circadian clocks have evolved independently in all three domains of life, suggesting that internal mechanisms of time-keeping are adaptive in contemporary populations. However, the performance consequences of either discrete or quantitative clock variation have rarely been tested in field settings. Clock sensitivity of diverse segregating lines to the environment remains uncharacterized as do the statistical genetic parameters that determine evolutionary potential. In field studies with Arabidopsis thaliana, we found that major perturbations to circadian cycle length (referred to as clock period) via mutation reduce both survival and fecundity. Subtler adjustments via genomic introgression of naturally occurring alleles indicated that clock periods slightly >24 hr were adaptive, consistent with prior models describing how well the timing of biological processes is adjusted within a diurnal cycle (referred to as phase). In segregating recombinant inbred lines (RILs), circadian phase varied up to 2 hr across months of the growing season, and both period and phase expressed significant genetic variances. Performance metrics including developmental rate, size and fruit set were described by principal components (PC) analyses and circadian parameters correlated with the first PC, such that period lengths slightly >24 hr were associated with improved performance in multiple RIL sets. These experiments translate functional analyses of clock behaviour performed in controlled settings to natural ones, demonstrating that quantitative variation in circadian phase is highly responsive to seasonally variable abiotic factors. The results expand upon prior studies in controlled settings, showing that discrete and quantitative variation in clock phenotypes correlates with performance in nature.

Heterogeneous selection at specific loci in natural environments in Arabidopsis thaliana.

Genetic variation for quantitative traits is often greater than that expected to be maintained by mutation in the face of purifying natural selection. One possible explanation for this observed variation is the action of heterogeneous natural selection in the wild. Here we report that selection on quantitative trait loci (QTL) for fitness traits in the model plant species Arabidopsis thaliana differs among natural ecological settings and genetic backgrounds. At one QTL, the allele that enhanced the viability of fall-germinating seedlings in North Carolina reduced the fecundity of spring-germinating seedlings in Rhode Island. Several other QTL experienced strong directional selection, but only in one site and seasonal cohort. Thus, different loci were exposed to selection in different natural environments. Selection on allelic variation also depended upon the genetic background. The allelic fitness effects of two QTL reversed direction depending on the genotype at the other locus. Moreover, alternative alleles at each of these loci caused reversals in the allelic fitness effects of a QTL closely linked to TFL1, a candidate developmental gene displaying nucleotide sequence polymorphism consistent with balancing selection. Thus, both environmental heterogeneity and epistatic selection may maintain genetic variation for fitness in wild plant species.