Detection and Coil Embolisation of Pelvic Venous Incompetence for Chronic Pain in the Female Pelvis: A Development Phase Economic Analysis.

OBJECTIVE: Unexplained chronic pain in the female pelvis (CPFP) affects 7% of people indicating female sex in the UK. Evidence suggests that pelvic venous incompetence (PVI) could explain CPFP and that coil embolisation could provide relief. The aims of this study were to indicate (1) the cost effectiveness of detecting and treating PVI in people experiencing unexplained CPFP, and (2) the maximum value of further research, suggesting suitable areas. METHODS: A decision tree compared standard care (regular prescribed analgesia) with an intervention comprising transvaginal duplex ultrasound to screen for PVI, venography to confirm the diagnosis, and coil embolisation treatment. The population was people experiencing unexplained CPFP. A UK National Health Service perspective and 2021 - 22 price year were used. Ten years of health costs and health related quality of life (HRQoL) effects for eligible 40 year olds were simulated. Evidence reviews informed diagnostic accuracy, health service usage, and unit costs. A single centre randomised controlled trial informed all other parameters. Probabilistic analysis incorporated parameter uncertainty in cost effectiveness estimates. Deterministic sensitivity analysis indicated drivers of uncertainty. Value of information methods measured the value of eliminating all relevant uncertainties, given uptake predictions. The main outcome measures were incremental cost and quality adjusted life years (QALYs) for the intervention compared with analgesia, the incremental cost effectiveness ratio (ICER), and expected value of perfect information. RESULTS: The mean ICER for the intervention was £4 558/QALY gained, and the probability that the ICER was within the UK cost effectiveness threshold (£20 000/QALY gained) was 90%. The expected value of perfect information about all model parameters was £46 M. All deterministic sensitivity analysis scenarios met the threshold, except the smallest plausible HRQoL effect of (resolving) CPFP. CONCLUSION: Detecting and treating PVI causing CPFP appears cost effective, but more primary research would be valuable to reduce decision uncertainty. Uncertainty in the HRQoL estimate for unexplained CPFP appeared to contribute most to decision uncertainty.

Rapid Carotid Screening by Duplex: A Prospective Single Centre Assessment.

OBJECTIVE: A novel carotid quick scan (CQS) protocol was developed to rapidly screen for carotid atherosclerosis greater than 50% stenosis in a vascular outpatient setting. This study assessed accuracy and time saved. MATERIAL & METHODS: The CQS was developed by consensus agreement between vascular surgeons and accredited clinical vascular scientists through a modified Delphi technique. The protocol comprised a rapid B-mode then colour flow transverse sweep of the common and internal carotid arteries, with internal carotid artery velocity assessment. One hundred outpatients attending with peripheral artery disease or abdominal aortic aneurysm were recruited. CQS sensitivity, specificity and accuracy was assessed against a conventional full carotid duplex study, performed to UK and ESVS guidelines. RESULTS: Twenty four percent of patients (n = 100) had >50% carotid NASCET stenosis. CQS achieved an excellent accuracy of 96.5% in detecting >50% stenosis when compared to full duplex; Cohen's ƙ = .88, (95%CI .79-.97; P < .001), sensitivity 91.4%, specificity 97.6%, positive predictive value (PPV) 88.9% and negative predictive value (NPV) 98.2%. Median (IQR) time to complete the CQS was 13 sec (±12) per side, compared to 151 sec (±78) per side for the full carotid duplex. In the presence of >50% carotid disease, median CQS time was 25 sec (±31) per side compared to 214 (±104) by full scan. CONCLUSION: CQS as a carotid screening tool is rapid, accurate and acceptable to the population and workforce. It would be simple to roll out in all vascular laboratories to reduce the time and cost burden of excluding significant carotid disease in any group.

Pelvic vein incompetence and chronic pelvic pain: a case-control study.

OBJECTIVE: To investigate the association between chronic pelvic pain (CPP) and pelvic vein incompetence (PVI) or pelvic varices. DESIGN: Case-control study. SETTING: Gynaecology and vascular surgery services in two teaching hospitals in north-west England. SAMPLE: A total of 328 premenopausal women (aged 18-54 years), comprising 164 women with CPP and 164 matched controls with no history of CPP. METHODS: Symptom and quality-of-life questionnaires and transvaginal duplex ultrasound for PVI and pelvic varices. MAIN OUTCOME MEASURES: Venous reflux of >0.7 s in the ovarian or internal iliac veins (primary outcome) and presence of pelvic varices (secondary outcome). Statistical analysis compared the prevalence of PVI between women with and without CPP using the two-sided chi-square test. Logistic regression was used to compare the odds of having PVI and pelvic varices between women with and without CPP. RESULTS: Pelvic vein incompetence was found on transvaginal duplex ultrasound in 101/162 (62%) women with CPP, compared with 30/164 (19%) asymptomatic controls (OR 6.79, 95% CI 4.11-11.47, p < 0.001). Forty-three of 164 (27%) women with CPP had pelvic varices compared with three of 164 (2%) asymptomatic women (OR 18.9, 95% CI 5.73-62.7, p < 0.001). CONCLUSIONS: There was a significant association between PVI, as detected by transvaginal duplex imaging, and CPP. Pelvic varices were strongly associated with CPP and were infrequently seen in control patients. These results justify further evaluation of PVI and its treatment in well-designed research.

Transvenous occlusion of incompetent pelvic veins to treat chronic pelvic pain in women: A randomised controlled trial.

OBJECTIVE: To investigate the effectiveness of transvenous occlusion of incompetent pelvic veins in women presenting with chronic pelvic pain (CPP) in improving symptoms and quality of life. DESIGN: Patient-blinded randomised controlled trial with objective outcome measures. Results were analysed on an intention-to-treat basis. SETTING: Gynaecology and Vascular Surgery Services of two teaching hospitals in northwest England. POPULATION: Sixty women aged 18-54 years presenting with CPP after exclusion of other pathology, and who were found to have pelvic vein incompetence. METHODS: Participants were randomised and assigned to contrast venography alone or contrast venography plus transvenous occlusion of the incompetent pelvic veins. MAIN OUTCOME MEASURE: The primary outcome was change in pain score measured using the short-form McGill Pain Score (SF-MPQ) and the Visual Analogue Score (VAS) recorded at 12 months post-randomisation. Secondary outcomes included quality of life using the EQ-5D instrument, symptomatic improvement and procedure-related complications. RESULTS: Sixty participants were randomised to transvenous occlusion of incompetent pelvic veins or venography only. At 12 months, median pain scored 2 (3-10) in the intervention group versus 9 (5-22) in controls (p = 0.016). Pain on the VAS scored 15 (0-3) versus 53 (20-71), respectively (p = 0.002). Median EQ-5D improved after intervention from 0.79 (0.74-0.84) to 0.84 (0.79-1.00; p = 0.008) over 12 months. No major complications were reported. CONCLUSION: Transvenous occlusion of pelvic vein incompetence reduced pain scores, improved quality of life and diminished symptom burden with no major reported complications. TRIAL REGISTRATION: ISRCTN 15091500.

Editor's Choice - The Abdominal Aortic Aneurysm Get Fit Trial: A Randomised Controlled Trial of Exercise to Improve Fitness in Patients with Abdominal Aortic Aneurysm.

OBJECTIVE: Ruptured abdominal aortic aneurysm (AAA) carries a mortality rate of up to 80%. Elective repair prevents rupture, but peri-operative mortality remains at 2% - 3%. This mortality rate and long term survival rate are associated with impaired peak oxygen uptake (peak VO2), oxygen uptake at anaerobic threshold (AT) and ventilatory equivalent for CO2 (VECO2) at AT on cardiopulmonary exercise testing (CPET). Improving fitness to optimise these variables could improve peri-operative and long term survival, but the required exercise training suitable for patients with AAA has yet to be established. This randomised controlled trial aimed to evaluate the effectiveness of 24 week, patient directed, community based exercise on CPET measured fitness in AAA surveillance patients. METHODS: This was a prospective randomised controlled trial in a tertiary UK vascular centre conducted using CONSORT guidelines. Patients on AAA surveillance (n = 56) were randomly assigned to either (1) a 24 week community exercise programme (CEP) with choice of gym or home exercises, or (2) standard clinical care including advice on weight loss and exercise. The primary outcome was change in peak VO2 at 24 weeks, with secondary outcomes including AT, VECO2, cardiovascular biomarkers (lipid profile, pro-B-type natriuretic peptide, and high sensitivity C reactive protein, body mass index, and HRQoL. Follow up was at eight, 16, 24, and 36 weeks to evaluate duration of benefit. All analyses were performed on an intention to treat basis. RESULTS: CEP patients (n = 28) achieved mean (95% confidence interval [CI]) improvements from baseline in peak VO2 of 1.5 (95% CI 0.5 - 2.5), 2.1 (95% CI 1.1 - 3.2), 2.3 (95% CI 1.2 - 3.3), and 2.2 (95% CI 1.1, 3.3) mL/kg/min at 8, 16, 24, and 36 weeks, respectively. These changes in CEP patients were significantly greater than those seen in control patients at 16 (p = .002), 24 (p = .031), and 36 weeks (p < .001). There were also significant improvements in AT, triglyceride levels, and HRQoL in CEP patients. CONCLUSION: This CEP significantly improved those CPET parameters associated with impaired peri-operative and long term survival in patients following AAA repair. These improvements were maintained at 12 weeks following the end of the programme.

Aneurysm Geometry Analyzed by the Novel Three-Dimensional Tomographic Ultrasound Relates to Abdominal Aortic Aneurysm Growth.

BACKGROUND: Abdominal aortic aneurysms (AAAs) are increasingly screen-detected and many small aneurysms enter surveillance. Computed tomography identifies characteristics that can predict subsequent AAA growth but ionizing radiation and nephrotoxic contrast disadvantage its use in surveillance. We investigated whether duplex and 3-dimensional tomographic ultrasound identified features associated with AAA growth in patients on AAA surveillance. METHODS: Duplex and three-dimensional tomographic ultrasound imaging was performed independently by 2 vascular scientists in 128 AAA surveillance patients who all had AAA growth measured over at least 2 years. Diameter, cross-sectional area, length, volume, wall thickness/volume, and intraluminal thrombus were measured. Pulsatility using maximum systolic and minimum diastolic diameters corrected for diameter and distensibility (consisting of strain and stiffness) were also calculated. RESULTS: AAA growth rate correlated with AAA diameter (r 0.43), volume (r 0.46), and cross-sectional area (r 0.42) (P < 0.01). Measuring wall thickness was inaccurate, but wall volume (corrected for AAA volume) inversely related to growth rate (r -0.43, P < 0.01). On a multivariate analysis, diameter and wall volume (r2adjusted 0.22, P < 0.01) improved prediction of growth rate compared with diameter alone (r2adjusted 0.18, P < 0.01). Intraluminal thrombus volume, strain distensibility, and elastic distensibility were not significantly associated with AAA growth. CONCLUSIONS: AAA growth most strongly related to AAA volume and inversely to wall volume. AAA volume and wall volume may prove useful in the prediction of AAA growth rates.

Evaluating Potential Autologous Bypass Grafts with Tomographic Three-Dimensional Ultrasound Compared with Standard Color Duplex.

BACKGROUND: Vein mapping using duplex ultrasound (DUS) is a routine in selecting optimal autologous bypass grafts (aBG) but is time consuming and operator-dependent. Tomographic three-dimensional (3D) ultrasound (tUS), using free-hand electromagnetic tracking, allows cardiac and vascular surgeons to view 3D images of the entire length of the potential bypass graft. This study compares tUS with DUS in the evaluation of potential autologous grafts for coronary and lower limb bypass. METHODS: Both DUS and tUS imaging of 434 potential autologous grafts (364 long, 22 short saphenous veins, and 48 radial artery) immediately before bypass surgery were compared. The time in minutes to evaluate each aBG was recorded. Surgeons scored the quality of the aBG at operation. A score of 5 was in complete agreement with preoperative imaging with scores of 4 considered "good". RESULTS: Most operating surgeons (113, 57%) preferred interpreting the tUS images and felt that this technology could replace DUS completely. The choice of aBG would have been changed as a result of tUS images in 64 (32%) cases. DUS imaging took a mean (+/-sd) of 08:26 ± 04:44 minutes compared with only 01:00 ± 00:25 minutes for tUS (P < 0.001). However, processing the tUS images, which is currently done manually by the vascular scientist, took significantly longer at 19:31 ± 12:41 minutes compared with 09:03 ± 09:12 minutes for reporting DUS (P < 0.001). CONCLUSIONS: Surgeons preferred to see tUS images of the potential aBG themselves rather than relying on DUS reports. tUS images were significantly quicker than DUS to acquire but needed more processing time.

Deep Vein Thrombosis is Common After Cardiac Ablation and Pre-Procedural D-Dimer Could Predict Risk.

PURPOSE: Cardiac catheter ablations are an established treatment for supraventricular tachycardia (SVT) involving prolonged cannulation of the common femoral vein with multiple catheters. This study aimed to identify the risk of deep vein thrombosis (DVT) by studying the frequency of this complication after catheter ablation. METHODS: This was a prospective multi-centre cohort study of patients undergoing cardiac ablation for atrioventricular nodal re-entry tachycardia or right-sided accessory atrioventricular connection. Those taking anticoagulation or antiplatelet therapy prior to the procedure were excluded. Following the procedure, bilateral venous duplex ultrasonography from the popliteal vein to the inferior vena cava for DVT was undertaken at 24 hours and between 10 to 14 days. RESULTS: Eighty (80) patients (mean age 47.6 yrs [SD 13.4] with 67% female) underwent cardiac ablation (median duration 70 mins). Seven (7) patients developed acute DVT in either the femoral or external iliac vein of the intervention leg, giving a frequency of 8.8% (95% CI 3.6-17.2%). No thrombus was seen in the contralateral leg (p=0.023). An elevated D-dimer prior to the procedure was significantly more frequent in patients developing DVT (42.9% vs 4.1%, p=0.0081; OR 17.0). No other patient or procedural characteristics significantly influenced the risk of DVT. CONCLUSION: In patients without peri-procedural anticoagulation catheter ablation precipitated DVT in the catheterised femoral or iliac veins in 8.8% of patients. Peri-procedure prophylactic anticoagulation may be considered for all patients undergoing catheter ablation for SVT. CLINICAL TRIAL REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT03877770.

Patients on AAA Surveillance are at Greater Threat of Cardiovascular Events or Malignancy than their AAA: Outcomes of AAA Surveillance over 19 years at a Tertiary Vascular Centre.

BACKGROUND: To analyse 19 years' worth of data from a Major UK Vascular Centre to determine the outcome of patients after they enter abdominal aortic aneurysm (AAA) surveillance (surgery, death, discharge or transfer), this may inform interventions to improve these outcomes in the AAA surveillance population. METHODS: This was a retrospective analysis of a prospectively collected database of outcomes of every patient entered on AAA surveillance at Manchester University NHS Foundation Trust - Wythenshawe Hospital between September 2000 and June 2019. Analyses included what proportion suffered death, discharge, transfer or surgery whilst on surveillance. Multi-variate analysis was used to determine the effect of initial AAA size, age when entering surveillance and gender. Boxplots were produced in those who had already reached an outcome to determine historic median times. Causes of death/discharge were also analysed. RESULTS: One thousand nine hundred fifty-one patients were identified from the databased after data cleaning and were included in the final analysis. Thirty-two percent of patients had died, 23.8% had surgery, 13.3% were discharged due to worsening/severe comorbidity, 3.1% had been transferred and 27.7% were still active in surveillance. A longer time to surgery was significantly associated with increasing age on entering surveillance OR (95% CI) 0.95 (0.94-0.96) (P < 0.001), smaller initial AAA size 4.26 (3.80-4.78) (P < 0.001) but not female gender. Impaired survival was associated with increasing age 1.06 (1.05-1.07) (P < 0.001), initial AAA size, 1.56 (1.39-1.74) (P < 0.001) and female gender 1.40 (1.18-1.67) (P < 0.001). Overall, death occurred more frequently than operative repair every year over all 15 years. Out of the deaths where cause was known (n = 401), 34.9% (n = 108) were due to cardiovascular events, 27.3% (n = 109) due to malignancy (primarily lung), and 19.3% due to respiratory disease. CONCLUSIONS: Based on this data, death, primarily due to cardiovascular events, is a more likely outcome than operative repair in patients on AAA surveillance and is associated with increasing age, increasing AAA size and female gender. A median time on surveillance of over three and a half years provides sufficient time to affect subsequent health outcomes in this population and therefore a shift of focus of AAA surveillance programmes to address cardiovascular, malignancy and respiratory disease risk is warranted.

Arteriovenous Fistula Surveillance Using Tomographic 3D Ultrasound.

OBJECTIVE: A well functioning arteriovenous fistula (AVF) is essential for haemodialysis. Despite regular duplex ultrasound (DUS) a significant number of AVFs fail. Tomographic 3D ultrasound (tUS) creates a 3D image of the AVF that can be interpreted by the clinician. DUS, tUS, and fistulograms were compared for the identification and measurement of flow limiting stenosis. METHODS: Patients with AVF dysfunction on routine Transonic surveillance, defined as (1) > 15% reduction in flow on two consecutive occasions, (2) > 30% reduction in flow on one occasion, (3) flow of < 600 mL/sec, (4) presence of recirculation, underwent DUS. AVF tUS imaging was performed prior to fistulography. All fistulograms were reported by the same consultant radiologist and tUS images by the same vascular scientist blinded to the fistulogram results. Maximum diameter reduction in all stenoses were measured using all three imaging techniques. RESULTS: In 97 patients with 101 stenoses, the mean (± standard deviation [SD]) severity of stenosis was 63.0 ± 13.9%, 65.0 ± 11.6%, and 64.8 ± 11.7% for the fistulograms, DUS, and tUS respectively. The mean (± SD) time between ultrasound and fistulography imaging was 15.0 ± 14.5 days. Assuming the fistulogram as the "gold standard", Bland-Altman agreement for DUS was -1.9 ± 15.5% (limit of agreement [LOA] -32.2 - 28.4) compared with -1.7 ± 15.4% (LOA -31.9 - 28.4) for tUS. Median (± interquartile range) time to complete the investigation was 09:00 ± 03:19 minutes for DUS and 03:13 ± 01:56 minutes for tUS (p < .001). CONCLUSION: DUS and tUS were equally accurate at detecting AVF complications but tUS investigation requires less skill and was significantly quicker than DUS.

Predicting Readmission to Intensive Care After Cardiac Surgery Within Index Hospitalization: A Systematic Review.

Readmission to the cardiac intensive care unit after cardiac surgery has significant implications for both patients and healthcare providers. Identifying patients at risk of readmission potentially could improve outcomes. The objective of this systematic review was to identify risk factors and clinical prediction models for readmission within a single hospitalization to intensive care after cardiac surgery. PubMed, MEDLINE, and EMBASE databases were searched to identify candidate articles. Only studies that used multivariate analyses to identify independent predictors were included. There were 25 studies and five risk prediction models identified. The overall rate of readmission pooled across the included studies was 4.9%. In all 25 studies, in-hospital mortality and duration of hospital stay were higher in patients who experienced readmission. Recurring predictors for readmission were preoperative renal failure, age >70, diabetes, chronic obstructive pulmonary disease, preoperative left ventricular ejection fraction <30%, type and urgency of surgery, prolonged cardiopulmonary bypass time, prolonged postoperative ventilation, postoperative anemia, and neurologic dysfunction. The majority of readmissions occurred due to respiratory and cardiac complications. Four models were identified for predicting readmission, with one external validation study. As all models developed to date had limitations, further work on larger datasets is required to develop clinically useful models to identify patients at risk of readmission to the cardiac intensive care unit after cardiac surgery.

Comparison Between Below Knee Contrast Enhanced Tomographic 3D Ultrasound and CT, MR or Catheter Angiography for Peripheral Artery Imaging.

OBJECTIVE: Clear imaging of below knee and foot arteries is essential to plan distal reconstructions. Contrast enhanced tomographic 3D ultrasound (CEtUS) is novel and entirely safe with no exposure to ionising radiation or nephrotoxic contrast. In the present study, inter- and intra-observer agreement of CEtUS was calculated, and compared with below knee angiography. METHODS: In the same week as computed tomography, magnetic resonance or catheter angiography, CEtUS was performed using intravenous 1.2 mL bolus injections of Sonovue with a maximum of 5 mL administered per patient. CEtUS was reported by a vascular scientist blinded to the angiograms reported by a consultant radiologist. Images were compared using a modified Society of Vascular Surgery (SVS) runoff score. RESULTS: Of the 181 patients recruited with peripheral arterial disease, 20 were excluded from analysis as they withdrew consent, could not be cannulated, or their images were non-diagnostic. In the remaining 161 patients, there were 175 comparative patient images split into two groups: 81 had calf imaging and 94 had pedal imaging representing 405 and 198 imaged arteries, respectively. Weighted quadratic kappa/ICC values for intra- and inter-observer agreement were excellent (κ/ICC = 0.83 to 0.95) and had narrow confidence intervals in both groups. When comparing angiography and CEtUS, weighted quadratic κ/ICC agreement was moderate with acceptable confidence intervals in both groups (Calf κ/ICC = 0.54; Pedal κ/ICC = 0.53). Agreement decreased from popliteal to pedal vessels as diameter decreased. Agreement between CEtUS and digital subtraction angiography was best, and computed tomography angiography the weakest. CONCLUSION: CEtUS is a novel imaging modality with strong observer agreement that achieves clear peripheral and foot images without ionising radiation exposure or nephrotoxic X-ray contrast media. CEtUS enhances visualisation of runoff vessels, which may play a role in planning of limb salvage or targeted assessment.

Resistance to Antiplatelet Therapy Is Associated With Symptoms of Cerebral Ischemia in Carotid Artery Disease.

BACKGROUND: Platelet inhibitory therapy is prescribed to prevent arterial thromboembolism in patients with atherosclerotic disease. Although taken by millions of people, around 30% are resistant to the treatment they are being prescribed. AIMS: To determine whether symptoms of cerebral ischemia, or pre-operative cerebral emboli, in patients admitted for a carotid endarterectomy were associated with resistance to aspirin or clopidogrel. METHODS: Venous blood from 133 patients immediately before carotid endarterectomy (CEA) was analyzed for resistance to aspirin and clopidogrel by multiplate impedance aggregometry. The number of emboli/hour entering the ipsilateral middle cerebral artery was counted by transcranial Doppler (TCD) on the day before surgery in 33 of these patients. RESULTS: Resistance was found in 21 (26.3%) of 100 patients taking aspirin and 14 (42%) of 33 taking clopidogrel. Mean (sd) residual platelet aggregation was significantly higher at 41.9(32) Au in patients who had suffered recent symptoms of cerebral ischemia compared with 30.8(16) Au in asymptomatic patients (p = 0.012). Residual platelet aggregation also correlated significantly with the number of emboli/hour counted by TCD in the ipsilateral middle cerebral artery (r = 0.45, p = 0.009). CONCLUSION: Antiplatelet resistance was associated with the frequency of cerebral emboli and recent symptoms of cerebral ischemia in patients with carotid disease. Definitive clinical studies are needed to explore whether testing for antiplatelet resistance should be undertaken routinely in patients starting platelet inhibitory therapy for cardiovascular disease.

A pilot multi-centre prospective randomised controlled trial of RECELL for the treatment of venous leg ulcers.

Venous leg ulcers (VLUs) have a significant impact on approximately 3% of the adult population worldwide, with a mean NHS wound care cost of £7600 per VLU over 12 months. The standard care for VLUs is compression therapy, with a significant number of ulcers failing to heal with this treatment, especially with wound size being a risk factor for non-healing. This multicentre, prospective, randomised trial evaluated the safety and effectiveness of autologous skin cell suspension (ASCS) combined with compression therapy compared with standard compression alone (Control) for the treatment of VLUs. Incidence of complete wound closure at 14 weeks, donor site closure, pain, Health-Related Quality of Life (HRQoL), satisfaction, and safety were assessed in 52 patients. At Week 14, VLUs treated with ASCS + compression had a statistically greater decrease in ulcer area compared with the Control (8.94 cm2 versus 1.23 cm2 , P = .0143). This finding was largely driven by ulcers >10 to 80 cm2 in size, as these ulcers had a higher mean percentage of reepithelialization at 14 weeks (ASCS + compression: 69.97% and Control: 11.07%, P = .0480). Additionally, subjects treated with ASCS + compression experienced a decrease in pain and an increase in HRQoL compared with the Control. This study indicates that application of ASCS + compression accelerates healing in large venous ulcers.

Are Serum Potassium and Magnesium Levels Associated with Atrial Fibrillation After Cardiac Surgery?

OBJECTIVES: Potassium and magnesium are frequently administered after cardiac surgery to reduce the risk of atrial fibrillation (AF). The evidence for this practice is unclear. This study was designed to evaluate the relationship between serum potassium and magnesium levels and AF after cardiac surgery. DESIGN: Observational cohort study. SETTING: A cardiac intensive care unit in the United Kingdom. PARTICIPANTS: Patients undergoing cardiac surgery between January 2013 and November 2017. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Cardiac rhythm was assessed using continuous electrocardiogram (ECG) monitoring in 3,068 patients on the cardiac intensive care unit. Associations between serum potassium and magnesium concentrations extracted from hospital databases and postoperative AF were assessed using univariable and multivariable analyses. The association between electrolyte supplementation therapy and AF was also analyzed. AF developed within 72 hours of cardiac surgery in 545 (17.8%) of the 3,068 patients. After adjusting for logistic EuroSCORE, surgery type, cardiopulmonary bypass time and age, mean serum potassium concentration <4.5 mmol/L was associated with an increased risk of AF (odds ratio [OR] 1.43 (95% confidence interval (CI): 1.17-1.75), p < 0.001). Mean magnesium concentration <1.0 mmol/L was not associated with an increased risk of AF (OR 0.89, 0.71-1.13, p = 0.342), but the administration of magnesium was associated with increased risk of developing AF (OR 1.61, 1.33-1.96, p < 0.001). CONCLUSIONS: Maintaining a serum potassium concentration ≥4.5 mmol/L after cardiac surgery may reduce the incidence of postoperative AF. Magnesium supplementation was associated with an increased risk of postoperative AF. Prospective randomized trials are required to clarify these associations.

A Novel Patient-Specific Model for Predicting Severe Oliguria; Development and Comparison With Kidney Disease: Improving Global Outcomes Acute Kidney Injury Classification.

OBJECTIVES: The Kidney Disease: Improving Global Outcomes urine output criteria for acute kidney injury lack specificity for identifying patients at risk of adverse renal outcomes. The objective was to develop a model that analyses hourly urine output values in real time to identify those at risk of developing severe oliguria. DESIGN: This was a retrospective cohort study utilizing prospectively collected data. SETTING: A cardiac ICU in the United Kingdom. PATIENTS: Patients undergoing cardiac surgery between January 2013 and November 2017. INTERVENTIONS: None. MEASUREMENT AND MAIN RESULTS: Patients were randomly assigned to development (n = 981) and validation (n = 2,389) datasets. A patient-specific, dynamic Bayesian model was developed to predict future urine output on an hourly basis. Model discrimination and calibration for predicting severe oliguria (< 0.3 mL/kg/hr for 6 hr) occurring within the next 12 hours were tested in the validation dataset at multiple time points. Patients with a high risk of severe oliguria (p > 0.8) were identified and their outcomes were compared with those for low-risk patients and for patients who met the Kidney Disease: Improving Global Outcomes urine output criterion for acute kidney injury. Model discrimination was excellent at all time points (area under the curve > 0.9 for all). Calibration of the model's predictions was also excellent. After adjustment using multivariable logistic regression, patients in the high-risk group were more likely to require renal replacement therapy (odds ratio, 10.4; 95% CI, 5.9-18.1), suffer prolonged hospital stay (odds ratio, 4.4; 95% CI, 3.0-6.4), and die in hospital (odds ratio, 6.4; 95% CI, 2.8-14.0) (p < 0.001 for all). Outcomes for those identified as high risk by the model were significantly worse than for patients who met the Kidney Disease: Improving Global Outcomes urine output criterion. CONCLUSIONS: This novel, patient-specific model identifies patients at increased risk of severe oliguria. Classification according to model predictions outperformed the Kidney Disease: Improving Global Outcomes urine output criterion. As the new model identifies patients at risk before severe oliguria develops it could potentially facilitate intervention to improve patient outcomes.

An Ex Vivo Evaluation of Tomographic 3-D Ultrasound, B-Mode Ultrasound, CT And MR Imaging to Measure Artery Diameter, Length and Wall Volume.

Precise measurement of luminal diameter in arteries is important when planning interventional vascular procedures in patients. Measuring wall volume may be important in detecting early artery disease and in the assessment of treatments to prevent atherosclerosis. An ex vivo phantom using porcine arteries was used to evaluate the accuracy with which (i) B-mode ultrasound, (ii) 3-D tomographic ultrasound (tUS), (iii) computed tomography (CT) and (iv) magnetic resonance imaging (MRI) measured length, diameters and volume. The mean error in inner-to-inner diameter measurements by B mode, tUS, CT and MRI were 0.08 ± 0.26, -0.73 ± 0.96 mm, 0.09 ± 0.55 and 0.60 ± 1.01 mm, respectively. The mean error in outer-to-outer diameter measurements by B mode, tUS, CT and MRI were -1.33 ± 0.61, -1.03 ± 0.35, 0.02 ± 1.00 and -0.47 ± 1.32 mm, respectively. The mean error in volume measurements by B mode, tUS, CT and MRI were -0.54 ± 0.62, -0.06 ± 0.09, 0.01 ± 0.18 and -0.20 ± 0.32 cm3, respectively. Errors in length and diameters remain within clinically acceptable thresholds where MRI was the least accurate. tUS was the most accurate method of volume measurement.

Comparison of Contrast-Enhanced Tomographic 3-D Ultrasound Against Rotational Angiography Imaging Immediately After Endovascular Aneurysm Repair.

This proof of principle study assesses the utility of contrast-enhance ultrasound (CEUS) and contrast-enhanced tomographic 3-D ultrasound (CEtUS), as an intra-procedural imaging tool after endovascular-aneurysm repair (EVAR), compared with rotational angiography. A total of 20 consecutive patients undergoing infra-renal EVAR underwent immediate post-deployment rotational angiography, followed by CEUS and CEtUS scans. Outcomes were presence of endoleak, renal artery patency and endograft deformity. CEUS and CEtUS detected 12 endoleaks, 8 of which were not detected by rotational angiography. CEUS and CEtUS classify 7 or 8 type IIb endoleaks not detected by rotational angiography. CEUS/CEtUS could not identify 12 and 13 renal arteries, respectively, detected by rotational angiography. Rotational angiography and CEtUS both identified 1 endograft limb deformity, corrected immediately. CEUS and CEtUS are more sensitive to type II endoleak than rotational angiography, although there is a lower detection of renal arteries. CEUS or CEtUS has the utility for immediate post-EVAR endoleak detection where reduction of contrast agent is indicated.