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Abstract Dense, vertically aligned multiwall carbon nanotubes were synthesized on TiN electrode layers for infrared sensing applications. Microwave plasma-enhanced chemical vapor deposition and Ni catalyst were used for the nanotubes synthesis. The resultant nanotubes were characterized by SEM, AFM, and TEM. Since the length of the nanotubes influences sensor characteristics, we study in details the effects of changing Ni and TiN thickness on the physical properties of the nanotubes. In this paper, we report the observation of a threshold Ni thickness of about 4 nm, when the average CNT growth rate switches from an increasing to a decreasing function of increasing Ni thickness, for a process temperature of 700°C. This behavior is likely related to a transition in the growth mode from a predominantly “base growth” to that of a “tip growth.” For Ni layer greater than 9 nm the growth rate, as well as the CNT diameter, variations become insignificant. We have also observed that a TiN barrier layer appears to favor the growth of thinner CNTs compared to a SiO2 layer.

Abstract Background Mast cells contribute to tissue repair in fibrous tissues by stimulating proliferation of fibroblasts through the release of tryptase which activates protease-activated receptor-2 (PAR-2). The possibility that a tryptase/PAR-2 signaling pathway exists in skeletal muscle cell has never been investigated. The aim of this study was to evaluate whether tryptase can stimulate myoblast proliferation and determine the downstream cascade. Methods Proliferation of L6 rat skeletal myoblasts stimulated with PAR-2 agonists (tryptase, trypsin and SLIGKV) was assessed. The specificity of the tryptase effect was evaluated with a specific inhibitor, APC-366. Western blot analyses were used to evaluate the expression and functionality of PAR-2 receptor and to assess the expression of COX-2. COX-2 activity was evaluated with a commercial activity assay kit and by measurement of PGF2α production. Proliferation assays were also performed in presence of different prostaglandins (PGs). Results Tryptase increased L6 myoblast proliferation by 35% above control group and this effect was completely inhibited by APC-366. We confirmed the expression of PAR-2 receptor in vivo in skeletal muscle cells and in satellite cells and in vitro in L6 cells, where PAR-2 was found to be functional. Trypsin and SLIGKV increased L6 cells proliferation by 76% and 26% above control, respectively. COX-2 activity was increased following stimulation with PAR-2 agonist but its expression remained unchanged. Inhibition of COX-2 activity by NS-398 abolished the stimulation of cell proliferation induced by tryptase and trypsin. Finally, 15-deoxy-Δ-12,14-prostaglandin J2 (15Δ-PGJ2), a product of COX-2-derived prostaglandin D2, stimulated myoblast proliferation, but not PGE2 and PGF2α. Conclusions Taken together, our data show that tryptase can stimulate myoblast proliferation and this effect is part of a signaling cascade dependent on PAR-2 activation and on the downstream activation of COX-2.

Background: The purpose of this study was to examine sex-based trends in incidence of elective abdominal aortic aneurysm (AAA), ruptured AAA, ruptured AAA repair, and AAA-related mortality., Methods: A retrospective analysis of patients presenting with AAA from 2005 to 2015 was conducted. Rates of elective AAA repair, ruptured AAA, ruptured AAA repair, and mortality were obtained from linking provincial administrative data using medical services insurance billing number. The age-adjusted incidence of elective AAA repair, overall rate of ruptured AAA, ruptured AAA repair, and AAA-related mortality was calculated for each sex based on Canadian census estimates, adjusted to the Canadian standard population. Weighted linear regression was performed to analyze trends in incidence over time., Results: One thousand nine hundred eighty-six elective AAA repairs were identified, of which 1,098 were repaired open and 898 underwent endovascular abdominal aneurysm repair (EVAR). Five hundred and seventy ruptured AAAs were identified, of which 295 (52%) were repaired: 259 open and 36 EVAR. The proportion of ruptured AAA that was repaired did not change over time (P = 0.54). The proportion repairs performed using EVAR increased significantly in both elective (P < 0.001) and rupture repairs (P < 0.001). During the study period, 662 patients died of AAA-associated mortality. The average incidence of elective AAA repair in men was 29.3 (95% confidence interval (CI): 27.8 to 30.8) per 100,000 and decreased over time (P = 0.04), whereas the average incidence in women was 9.2 [8.3 to 10.0] and stable (P = 0.07). The incidence of open elective AAA repair was 10.5 [9.9-11.1] with a decreasing trend over time (P < 0.001) and EVAR was 9.0 (8.5-9.6) with an increasing trend over time (P < 0.001). A decreasing trend of overall ruptured AAA (5.4 [5.0-5.9], P < 0.001), ruptured AAA repair (2.9 [2.5-3.2], P = 0.02), and of AAA-related mortality (6.2 [5.8-6.8], P < 0.001) was found, with consistent trends in both sexes. The incidence of open ruptured AAA repair decreased over time (P = 0.001) whereas the incidence of ruptured EVAR remained stable (P = 0.23)., Conclusions: The incidence of elective AAA repair is decreasing in males but not females, whereas the incidence of rupture has decreased in both sexes. This has translated into reduced incidence of AAA-related mortality. Increased adoption of EVAR for ruptured AAA should continue these trends., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Objective: Ruptured abdominal aortic aneurysms (RAAAs) are surgical emergencies that require immediate and expert treatment. It has been unclear whether presentation during evenings and weekends, when "on call" teams are primarily responsible for patient care, is associated with worse outcomes. Our objective was to evaluate the outcomes of patients presenting with RAAAs after-hours vs during the workday., Methods: A retrospective cohort study of all RAAAs in Nova Scotia between 2005 and 2015 was performed through linkage of administrative databases. Patients who had presented to the hospital with RAAAs during the workday (Monday through Friday, 6 am to 6 pm) were compared with those who had presented after-hours (6 pm to 6 am during the week and on weekends). The baseline and operative characteristics were identified for all patients through the available databases and a review of the medical records. Mortality before surgery, 30-day mortality, and operative mortality were compared between groups using multivariable logistic regression, adjusting for factors clinically significant on univariable analysis., Results: A total of 390 patients with RAAAs were identified from 2005 to 2015, of whom 205 (53%) had presented during the workday and 185 (47%) after-hours. The overall chance of survival (OCS) was 45% overall, 49% if admitted to hospital, and 64% if surgery had been performed. During the workday, the OCS was 43% overall, 48% if admitted to hospital, and 67% if surgery had been performed. After-hours, the OCS was 46% overall, 49% if admitted to hospital, and 61% if surgery had been performed. Mortality before surgery was increased for patients who had presented to the hospital during the workday compared with after-hours (36% vs 26%; P = .04). The 30-day mortality (57% vs 54%; P = .62), rates of operative management (63% vs 72%; P = .06), and operative mortality (33% vs 39%; P = .33) were similar between the workday and after-hours groups (57% vs 54%; P = .06). After adjusting for significant clinical variables, the patients who had presented with RAAAs after-hours had had a similar odds of dying before surgery (odds ratio [OR], 0.64; 95% confidence interval [CI], 0.41-1.03), operative management (OR, 1.47; 95% CI, 0.93-2.31), 30-day mortality (OR, 0.98; 95% CI, 0.63-1.51), and operative mortality (OR, 1.33; 95% CI, 0.78-2.26). In the subgroup of patients presenting to a hospital with endovascular capabilities, patients presenting after-hours had had similar odds of 30-day mortality (OR, 1.07; 95% CI, 0.57-2.02), and operative mortality (OR, 1.14; 95% CI, 0.58-2.23)., Conclusions: We found that patients presenting to the hospital with RAAAs after-hours did not have increased adjusted odds of mortality before surgery, operative management, 30-day mortality, or operative mortality., (Copyright © 2022 Society for Vascular Surgery. Published by Elsevier Inc. All rights reserved.)

Background: Centralization of vascular surgery care for Ruptured Abdominal Aortic Aneurysms (RAAAs) to high-volume tertiary centers may hinder access to timely surgical intervention for patients in remote areas. The objective of this study was to determine the association between distance from vascular care and mortality from RAAAs in the province of Nova Scotia, Canada., Methods: A retrospective cohort study of all RAAAs in Nova Scotia between 2005 and 2015 was performed through linkage of administrative databases. Patients were divided into groups by estimated travel time from their place of residence to the tertiary center (<1 hr and ≥1 hr) using geographic information software. Baseline and operative characteristics were identified for all patients through available databases and completed through chart review. Mortality at home, during transfer to the vascular center, and overall 30-day mortality were compared between groups using t-test and chi-squared test, as appropriate. Multivariable logistic regression analysis was used to calculate the independent effect of travel time on survival outcomes., Results: A total of 567 patients with RAAA were identified from 2005-2015, of which 250 (44%) resided <1 hr travel time to the tertiary center and 317 (56%) resided ≥1 hr. On multivariable analysis, travel time ≥1 hr from vascular care was an independent predictor of mortality at home (odds ratio [OR] 1.68, 95% confidence interval [CI] 1.07-2.63, P = 0.02), mortality prior to operation (OR 2.64, 95% CI 1.81-3.83, P < 0.001), and overall 30-day mortality (OR 1.61, 95% CI 1.10-2.37, P = 0.02). In patients who received an operation (n = 294), there was no association between increased travel time and mortality (OR 1.02, 95% CI 0.60-1.73, P = 0.94)., Conclusions: Travel time ≥1 hr to the tertiary center is associated with significantly higher mortality from ruptured abdominal aortic aneurysm (AAA). However, there was no difference in overall chance of survival between groups for patients that underwent AAA repair. Therefore, strategies to facilitate early detection, and timely transfer to a vascular surgery center may improve outcomes for patients with RAAA., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: The association between socioeconomic status (SES) and outcomes after abdominal aortic aneurysm (AAA) repair in publicly funded health care systems is poorly described. The purpose of this study was to determine the effect of SES on postoperative outcomes in patients who underwent AAA repair in Nova Scotia, Canada., Methods: We performed a retrospective analysis of all elective AAA repairs in Nova Scotia between November 2005 and March 2015 using administrative data sources. We compared postoperative 30-day outcomes and long-term survival across socio-economic quintiles, defined as the Pampalon Material Deprivation Index (MDI) and Social Deprivation Index (SDI). We also compared the relation between baseline characteristics, MDI quintile, SDI quintile and 30-day mortality. We used multivariable logistic regression and survival analysis to calculate adjusted 30-day mortality and long-term survival, respectively., Results: A total of 1913 patients underwent AAA repair during the study period. The overall 30-day mortality rate was 2.6% (50 patients). Thirty-day outcomes including death ( p = 0.8), stroke ( p = 0.7), myocardial infarction ( p = 0.06), length of stay ( p = 0.3) and discharge disposition other than home ( p = 0.8) were similar across MDI quintiles. Similarly, there was no statistically significant association between SDI quintile and postoperative outcomes. Multivariable analysis showed that age greater than 70 years (odds ratio [OR] 3.06, 95% confidence interval [CI] 1.55-6.06) and open repair (OR 3.22, 95% CI 1.59-6.52) but not MDI quintile ( p = NS) or SDI quintile ( p = NS) were associated with increased 30-day mortality. There was no effect of MDI or SDI quintile on long-term survival on univariable or multivariable analysis., Conclusion: Socioeconomic status does not appear to affect short- or long-term mortality after AAA repair in a publicly funded health care system. Further research is needed to address any existing gaps in screening and referral before repair., Competing Interests: Competing interests: None declared., (© 2023 CMA Impact Inc. or its licensors.)

Background: Atrial functional mitral regurgitation (FMR) occurs because of left atrial dilatation or atrial fibrillation in heart failure with preserved left ventricular (LV) function, contrary to ventricular FMR, which occurs because of LV dysfunction. Despite pathophysiological differences, current guidelines do not discriminate between these 2 entities., Methods: From January 2002 to March 2019, all adult patients with ≥3+ mitral regurgitation who underwent mitral valve repair or replacement were identified. Postoperative outcomes and midterm time-to-event rates (survival and reoperation) were compared., Results: Overall, 94 atrial FMR (mean age, 67.6 years) and 84 ventricular FMR (mean age, 64 years) patients met inclusion criteria. Differences in baseline cardiac morphology and function of the atrial FMR and ventricular FMR patients were as follows: concomitant atrial fibrillation (37.2% vs 14.3%), heart failure (42.6% vs 63.1%), LV ejection fraction (60% vs 37%), at least moderate LV dilation (4.8% vs 40.6%), and moderate/severe right heart dysfunction (15.2% vs 5.1%), respectively. Operative mortality was 0% in the atrial FMR versus 1.2% in the ventricular FMR cohort. Actuarial estimates of survival and freedom from reoperation at 5 and 10 years was significantly higher in the atrial FMR cohort versus the ventricular FMR cohort. Ventricular FMR also remained a significant predictor of midterm mortality in our risk-adjusted analysis (adjusted hazard ratio for ventricular FMR, 1.8; 95% confidence interval, 1.001-3.26)., Conclusions: There are important differences in baseline characteristics in terms of cardiac morphology and function among atrial FMR and ventricular FMR patients, which appear to affect in-hospital and midterm outcomes. Because of these discrepancies, early discrimination between these 2 etiologies of FMR might facilitate more tailored approaches to management., (Copyright © 2020 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.)

Background: The purpose of this study was to examine trends in the incidence of thoracic aortic aneurysm (TAA) repair and aortic dissection., Methods: A retrospective study was conducted of patients from the period 2005-2015 with thoracic aortic disease. Unadjusted mortality was compared in women vs men. Rates of scheduled TAA repair, dissection events, acute type A aortic dissection (TAAD) repair, and aorta-related mortality were obtained from our institution's clinical registry and administrative data sources and used to calculate the age-adjusted incidence for each sex, adjusted to the Canadian standard population. Weighted linear regression was performed to analyze trends over time., Results: A total of 382 scheduled TAA repair operations, 345 dissection events, 85 TAAD repairs, and 182 aorta-related mortalities were identified. Women accounted for 23% of TAA repairs, 39% of dissection events, 22% of TAAD repairs, and 45% of aorta-related mortalities. The incidence of TAA repair was 3.5 per 100,000 person-years (95% confidence interval [CI]: 3.2-3.9), and increased in men ( P  = 0.02) but not women ( P  = 0.10) over time. The incidence of aortic dissection was 3.4 per 100,000 (95% CI: 3.1-3.8) and was stable over time ( P  = 0.43). The average annual age-adjusted incidence of TAAD repair was 0.8 per 100,000 (95% CI: 0.6-1.0) and increased over time ( P  = 0.001). The overall incidence of aorta-related mortality was 1.8 per 100,000 (95% CI: 1.5-2.0) and decreased over time ( P  = 0.02)., Conclusion: The incidence of TAA repair is increasing in men but not women. Although aorta-related mortality is decreasing overall, disparities exist between the male and female population., (© 2022 The Authors.)

Background: The association between travel time from tertiary care centre and outcomes after ascending thoracic aortic surgery is unknown. We determined the effect of travel time from the tertiary care centre on outcomes in ascending aortic repair in Nova Scotia., Methods: A retrospective analysis of patients undergoing elective and emergent ascending thoracic aortic operations from 2005 to 2015 was carried out. Patient's residential geographic coordinates were used to calculate travel time to the tertiary care centre, and patients who resided < 1 hour vs ≥ 1 hour were compared. Multivariable logistic regression was performed to determine the effect of travel time on in-hospital outcomes. Cox-proportional hazard modelling and Kaplan-Meier survival estimates were created to determine the effect on long-term survival., Results: A total of 476 patients underwent ascending thoracic aortic surgery from 2005 to 2015. Patients who resided < 1 hour from the tertiary care centre vs patients who resided ≥ 1 hour had similar rates of in-hospital mortality (4.4% vs 6.1%, P = 0.42), in-hospital composite complications (66.7% vs 67.7%, P = 0.80), hospital length of stay (median 9 days; interquartile range [7-16] vs 10 [7-17], P = 0.41), and discharge disposition other than home (9.7% vs 11.7%, P = 0.55). Compared with patients who resided < 1 hour from the tertiary centre, patients who resided ≥ 1 hour were at higher risk for long-term mortality (hazard ratio, 2.19; 95% confidence interval, 1.13-4.28; P = 0.02)., Conclusions: Patients who reside remotely from the tertiary centre experience equivalent in-hospital outcomes but decreased long-term survival following ascending aortic operations. These findings may guide resource expansion for postoperative follow-up., (Copyright © 2022 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background and Aim of the Study: Long-term laryngotracheal complications have not been described in adult patients undergoing cardiac surgery. The purpose of this study was to determine the incidence of and risk factors for laryngotracheal complications following cardiac surgery., Methods: A retrospective chart review of patients at high risk for laryngotracheal complications following cardiac surgery between 2006 and 2016 was performed. High-risk patients were reviewed to determine the presence of laryngotracheal complications including laryngotracheal stenosis, keyhole deformity, or vocal cord immobility. Logistic regression was used to identify predictors of long-term laryngotracheal complications., Results: Of 11,417 patients who underwent cardiac surgery, 1099 were identified as at high risk. Of these, 24 (2.2%) developed laryngotracheal complications following their surgery and intensive care unit (ICU) stay. Laryngotracheal stenosis and keyhole deformity were present in 13 (1.2%) and 6 (0.5%) patients, respectively. Logistic regression demonstrated older age (age ≥ 70 odds ratio [OR] 0.31, 95% confidence interval [CI] 0.12-0.83) was protective, while readmission to ICU for ventilation (OR 3.11, 95% CI 1.17-8.25) and receiving a tracheostomy (OR 7.83, 95% CI 2.22-27.6) were associated with laryngotracheal complications., Conclusions: The incidence of long-term laryngotracheal complications following cardiac surgery was 2.2%. Readmission to ICU for ventilation and having a tracheostomy performed were associated with laryngotracheal complications., (© 2021 Wiley Periodicals LLC.)

Background: Placement of temporary epicardial pacing wires (TEPW) at the end of open heart surgery cases is routine but can be associated with complications. Identification of patients who are high risk for requiring pacing would be beneficial on guiding selective TEPW placement. The purpose of this study was to identify predictors of temporary pacing immediately post cardiac surgery., Methods: A retrospective analysis of patients undergoing cardiac surgery from 2005 to 2016 at the Maritime Heart Center was conducted. Analysis was performed of patients who require pacing on arrival to the cardiovascular intensive care unit (CVICU) compared with those who were not paced. Multivariable logistic regression was used to determine each variable's risk adjusted likelihood of pacing for the entire cohort. Subgroup analysis was performed in the isolated procedures., Results: A total of 11 752 patient underwent surgery from the year 2005 to 2016. Two thousand and fifty-one (17.5%) required pacing on arrival to CVICU. Older age, female sex, preoperative renal failure, lower ejection fraction (EF), preoperative arrhythmia, preoperative use of calcium channel blockers, and longer cross-clamp times were risk factors for pacing. In the isolated coronary artery bypass grafting and aortic valve replacement groups, findings were similar to the overall cohort. Only age, obesity, and chronic obstructive pulmonary disease were risk factors for pacing in the isolated mitral valve (MV) repair group and only preoperative arrhythmia in the isolated MV replacement group., Conclusion: We have identified risk factors for TEPW use following cardiac surgery and in isolated procedure subgroups. These risk factors may help guide selective TEPW placement., (© 2020 Wiley Periodicals LLC.)

Background and Aim of Study: Placement of temporary epicardial pacing wires (TEPW) is common practice in cardiac surgery. Removal of TEPW in the postoperative period can lead to serious bleeding necessitating surgical intervention and conferring high morbidity. The purpose of this study is to determine the incidence of TEPW removal complications., Methods: A retrospective review of all major cardiac operations at our institution from 2005 to 2016 was conducted. Patients were identified using the Maritime Heart Center Database. We reviewed preoperative, intra-operative, and postoperative characteristics of patients who returned to the operating room more than or equal to 3 days after their index operation to identify those who had bleeding and/or tamponade as a consequence of TEPW removal and any subsequent morbidity., Results: A total of 11 754 patients underwent cardiac surgery at our institution between 2005 and 2016. Of these patients, 88 (0.75%) went back to the operating theater for bleeding and/or tamponade more than or equal to 3 days from their initial index operation. Of these, 11 (0.09%) were secondary to TEPW removal where two (0.017%) suffered irreversible anoxic brain injury. All 11 patients were on antiplatelet therapy with the addition of either deep venous thrombosis (DVT) prophylaxis or therapeutic anticoagulation, which is the standard of care at our institution., Conclusions: Bleeding complications following TEPW removal are rare but have significant consequences including increased hospital length of stay, resource utilization, and morbidity. Standardized practice to address antiplatelet, DVT prophylaxis, and anticoagulation before removal may help further reduce the incidence of serious bleeding events., (© 2020 Wiley Periodicals, Inc.)

Minimally invasive cardiac surgery techniques offer better cosmesis, quicker recovery, and shorter hospital stay when compared with sternotomy. Large cardiac tumours have been traditionally resected via sternotomy to provide adequate surgical exposure, complete surgical resection, and prevent tumour fragmentation. We describe a patient with advanced multiple sclerosis and wheelchair dependence with a massive obstructive left atrial tumour who underwent successful minimally invasive en bloc resection with an uncomplicated postoperative course., (Copyright © 2016 Canadian Cardiovascular Society. Published by Elsevier Inc. All rights reserved.)

Background: Numerous studies have examined the effect of geographic place of residence on access to cardiovascular care, but few have examined their effect on outcomes after cardiac operations. This study examined the effect of geographic place of residence on in-hospital and 30-day outcomes after cardiac operations., Methods: We performed a retrospective analysis of all patients undergoing nonemergency cardiac operations at a single institution between April 2004 and March 2011. Geographic place of residence was defined as the driving distance from the patient's home to the tertiary cardiac care center divided into the following categories: 0 to 50 km, 50 to 100 km, 100 to 150 km, 150 to 200 km, 200 to 250 km, and more than 250 km. Multivariable logistic regression was used to determine the independent effect of driving distance on in-hospital and 30-day outcomes., Results: The final study population included 4,493 patients, of whom 3,897 (86.7%) had 30-day follow-up. After adjusting for differences among patient groups, no consistent relationship existed between distance and in-hospital outcomes. However, increased distance beyond 100 km was significantly associated with a greater risk of adverse outcomes at 30 days (0 to 50 km: referent; 50 to 100 km: odds ratio, 1.16 [95% confidence interval, 0.83 to 1.62]; 100 to 150 km: 1.32 [1.05 to 1.65], 150 to 200 km: 1.68 [1.33 to 2.11], 200 to 250 km: 1.41 [1.06 to 1.88], and >250 km: 1.30 [1.04 to 1.63])., Conclusions: Patients who live at an increased distance from the tertiary cardiac care center are more likely to have worse 30-day outcomes after cardiac operations. Further study is required to determine the mechanisms underlying this relationship and how such inequalities may be minimized., (Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)