Abnormal Iron Status and Adverse Outcome After Elective Cardiac Surgery: A Prospective, Observational Multicenter Study.

OBJECTIVES: To investigate the incidence of preoperative abnormal iron status and its association with packed red blood cell (PRBC) transfusion, postoperative major complications, and new onset of clinically significant disability in patients undergoing elective cardiac surgery. DESIGN: A prospective, observational multicenter cohort study. SETTING: Three cardiac surgical centers in the Netherlands between 2019 and 2021. Recruitment was on hold between March and May 2020 due to COVID-19. PATIENTS: A total of 427 patients aged 60 years and older who underwent elective on-pump cardiac surgery. MEASUREMENTS AND MAIN RESULTS: The primary endpoint was a 30-day PRBC transfusion. Secondary endpoints were postoperative major complications within 30 days (eg, acute kidney injury, sepsis), and new onset of clinically significant disability within 120 days of surgery. Iron status was evaluated before surgery. Abnormal iron status was present in 45.2% of patients (n = 193), and most frequently the result of iron deficiency (27.4%, n = 117). An abnormal iron status was not associated with PRBC transfusion (adjusted relative risk [ARR] 1.2; 95% CI 0.9-1.8: p = 0.227) or new onset of clinically significant disability (ARR 2.0; 95% CI 0.9-4.6: p = 0.098). However, the risk of postoperative major complications was increased in patients with an abnormal iron status (ARR 1.7; 95% CI 1.1-2.5: p = 0.012). CONCLUSIONS: An abnormal iron status before elective cardiac surgery was associated with an increased risk of postoperative major complications but not with PRBC transfusion or a new onset of clinically significant disability.

Dual-task walking and automaticity after Stroke: Insights from a secondary analysis and imaging sub-study of a randomised controlled trial.

OBJECTIVE: To test the extent to which initial walking speed influences dual-task performance after walking intervention, hypothesising that slow walking speed affects automatic gait control, limiting executive resource availability. DESIGN: A secondary analysis of a trial of dual-task (DT) and single-task (ST) walking interventions comparing those with good (walking speed ⩾0.8 m s-1, n = 21) and limited (walking speed <0.79 m s-1, n = 24) capacity at baseline. SETTING: Community. SUBJECTS: Adults six-months post stroke with walking impairment. INTERVENTIONS: Twenty sessions of 30 minutes treadmill walking over 10 weeks with (DT) or without (ST) cognitive distraction. Good and limited groups were formed regardless of intervention received. MAIN MEASURES: A two-minute walk with (DT) and without (ST) a cognitive distraction assessed walking. fNIRS measured prefrontal cortex activation during treadmill walking with (DT) and without (ST) Stroop and planning tasks and an fMRI sub-study used ankle-dorsiflexion to simulate walking. RESULTS: ST walking improved in both groups (∆baseline: Good = 8.9 ± 13.4 m, limited = 5.3±8.9 m, Group × time = P < 0.151) but only the good walkers improved DT walking (∆baseline: Good = 10.4 ± 13.9 m, limited = 1.3 ± 7.7 m, Group × time = P < 0.025). fNIRS indicated increased ispilesional prefrontal cortex activation during DT walking following intervention (P = 0.021). fMRI revealed greater DT cost activation for limited walkers, and increased resting state connectivity of contralesional M1 with cortical areas associated with conscious gait control at baseline. After the intervention, resting state connectivity between ipsilesional M1 and bilateral superior parietal lobe, involved in integrating sensory and motor signals, increased in the good walkers compared with limited walkers. CONCLUSION: In individual who walk slowly it may be difficult to improve dual-task walking ability.Registration: ISRCTN50586966.

Neural Substrates of Cognitive Motor Interference During Walking; Peripheral and Central Mechanisms.

Current gait control models suggest that independent locomotion depends on central and peripheral mechanisms. However, less information is available on the integration of these mechanisms for adaptive walking. In this cross-sectional study, we investigated gait control mechanisms in people with Parkinson's disease (PD) and healthy older (HO) adults: at self-selected walking speed (SSWS) and at fast walking speed (FWS). We measured effect of additional cognitive task (DT) and increased speed on prefrontal (PFC) and motor cortex (M1) activation, and Soleus H-reflex gain. Under DT-conditions we observed increased activation in PFC and M1. Whilst H-reflex gain decreased with additional cognitive load for both groups and speeds, H-reflex gain was lower in PD compared to HO while walking under ST condition at SSWS. Attentional load in PFC excites M1, which in turn increases inhibition on H-reflex activity during walking and reduces activity and sensitivity of peripheral reflex during the stance phase of gait. Importantly this effect on sensitivity was greater in HO. We have previously observed that the PFC copes with increased attentional load in young adults with no impact on peripheral reflexes and we suggest that gait instability in PD may in part be due to altered sensorimotor functioning reducing the sensitivity of peripheral reflexes.

Associations between prefrontal cortex activation and H-reflex modulation during dual task gait.

Walking, although a largely automatic process, is controlled by the cortex and the spinal cord with corrective reflexes modulated through integration of neural signals from central and peripheral inputs at supraspinal level throughout the gait cycle. In this study we used an additional cognitive task to interfere with the automatic processing during walking in order to explore the neural mechanisms involved in healthy young adults. Participants were asked to walk on a treadmill at two speeds, both with and without additional cognitive load. We evaluated the impact of speed and cognitive load by analyzing activity of the prefrontal cortex (PFC) using functional Near-Infrared Spectroscopy (fNIRS) alongside spinal cord reflex activity measured by soleus H-reflex amplitude and gait changes obtained by using an inertial measuring unit. Repeated measures ANOVA revealed that fNIRS Oxy-Hb concentrations significantly increased in the PFC with dual task (walking while performing a cognitive task) compared to a single task (walking only; p < 0.05). PFC activity was unaffected by increases of walking speed. H-reflex amplitude and gait variables did not change in response to either dual task or increases in walking speed. When walking under additional cognitive load participants adapted by using greater activity in the PFC, but this adaptation did not detrimentally affect H-reflex amplitude or gait variables. Our findings suggest that in a healthy young population central mechanisms (PFC) are activated in response to cognitive loads but that H-reflex activity and gait performance can successfully be maintained. This study provides insights into the mechanisms behind healthy individuals safely performing dual task walking.

Expression of placental growth factor in regenerating livers after partial hepatectomy in the rat.

BACKGROUND/AIMS: Placental growth factor (PlGF) is known for its role in pathological conditions to protect parenchymal cells of different organs from injury, whereas its presence in the liver and its potential importance in stimulating liver regeneration has never been described. This was investigated in this study using a rat model of partial hepatectomy (PH). METHODS: The rat model of 70, 80, and 90% PH was used. Liver samples were taken peroperatively, 1 h, 1, 2, 3, and 7 days after surgery. Liver regeneration was evaluated by liver weight/body weight ratio, liver regeneration rate (%), and proliferating cell marker Ki67. The expression of PlGF, vascular endothelial growth factor (VEGF), VEGF receptor 1 (Flt-1), VEGF receptor 2 (Flk-1), and hypoxia inducible factor-1α mRNA was measured by quantitative real-time PCR and localized by immunohistochemistry. RESULTS: The mRNA expression of PlGF was upregulated immediately after PH. Compared with 70 and 80% PH groups, the 90% PH group had a significantly lower PlGF and hypoxia inducible factor-1α mRNA expression, in parallel to a delayed liver weight/body weight ratio recovery. Only little differences were observed in VEGF, Flt-1, and Flk-1 mRNA expression among the PH groups. CONCLUSION: This study shows for the first time the PlGF upregulation in regenerating livers, which is related to hypoxia stimulation and liver growth. The swift PlGF upregulation immediately after PH may indicate an important role for the PlGF/Flt-1 pathway in the early stage of liver regeneration.

Endovascular treatment of a ureteroiliac fistula associated with ureteral double J-stenting and an aortic-bifemoral stent graft for an inflammatory abdominal aortic aneurysm.

We report an unusual case of a ureteroiliac fistula due to prolonged ureteral stenting for hydronephrosis combined with an aortic-bifemoral stent graft in an inflammatory abdominal aortic aneurysm (AAA), treated with an endovascular stent graft. In a 77-year-old man ureteral J-stents were placed for bilateral hydronephrosis due to retroperitoneal fibrosis caused by an inflammatory AAA. The aneurysm was treated with an endovascular aortic-bifemoral stent graft. Three months later, the patient suffered from severe hypovolemic shock. Emergency angiography showed a fistula between the right ureter and the right common iliac artery just distal to the right leg of the stent graft. The ureteroiliac fistula was treated with a wall graft (10F). The patient recovered well and remained asymptomatic. Ureteroiliac fistula remains a rare complication of ureteral stenting. Several risk factors have been described before. This case emphazes the increased risk of an arterial-ureteral fistula due to an indwelling ureteral stent and an inflammatory AAA, especially in combination with an additional stent graft for this inflammatory AAA.

The use of low dose octreotide prophylaxis in pancreatic transplants with enteric drainage. Results of a prospective randomized single center trial.

AIM: The aim of this study was to investigate the effect of octreotide in the perioperative course of pancreas transplants drained into the bowel in terms of fistula formation, pancreatitis, hemorrhage and thrombosis, and to compare the results to patients not receiving octreotide in a prospectively, randomized single center trial. PATIENTS AND METHODS: Forty pancreas transplant recipients were prospectively randomized to either receive or not to receive octreotide 0.1 mg subcutaneously at the time of operation and 3x/d there after until post-operative day 7. The incidence of pancreatic leakage from the anastomosis and the content of peritoneal fluid drainage regarding amylase and lipase concentrations collected by abdominal drains were registered on day 0-10. Both groups were comparable for age, sex, onset of diabetes, surgical procedure and immunosuppressive regimen. RESULTS: There were 35 simultaneous pancreas-kidney transplants and five solitary pancreas transplants, two in the octreotide and three in the control group two pancreas after kidney, one pancreas after liver pancreas, one pancreas after simultaneous pancreas kidney transplantation, one pancreas transplant alone. All had enteric drainage. Twenty patients received octreotide and 20 did not. In one patient, receiving octreotide the pancreas had to be removed for septic complications because of an enteric fistula arising from the anastomosis (1/20 = 5%). The incidence in patients on octreotide vs. non-octreotide was 1 vs. 0 for pancreatitis, 2 vs. 3 for hemorrhage, 2 vs. 1 for thrombosis and 2 vs. 0 for pancreatic fistulae resulting in an actual overall 12 months patient survival of 100% in both groups and a pancreas survival of 85% vs. 95%. For primary simulaneous pancreas kidney the pancreas graft survival was 93%. The amylase and lipase concentrations of fluid collections drained into the peritoneum on day 0 to 10 post-operatively indicating pancreatic fistulization was comparable in both groups. CONCLUSION: The use of octreotide following pancreas transplantation did not prevent pancreatic fistula formation from the anastomosis neither from the pancreatic capsule in pancreas transplantation with enteric drainage. Further studies are required to finally evaluate the benefit of this prophylactic treatment.