A systematic review and meta-analysis of concomitant truncal and perforator surgery.

OBJECTIVE: Incompetent perforator veins are encountered frequently during ultrasound assessment of the venous system in chronic venous disease. Some studies have shown that concomitant treatment of truncal and perforator incompetence improves ulcer healing, yet a Cochrane review was unable to determine the potential benefits of perforator surgery in venous ulcer management due to poor quality evidence. This study aims to establish the exact role of concomitant treatment in patients with chronic venous disease. METHODS: A search of online databases including MEDLINE, Embase, and Cochrane was performed in March 2022. All studies comparing the outcomes of concomitant superficial venous plus perforator surgery with standard therapy were included. Variables assessed included ulcer healing, time to healing, and ulcer recurrence. Disease severity and quality of life, vein occlusion rates, number of incompetent perforator veins on duplex ultrasound post treatment, and reintervention and complication rates were also analyzed. Data were pooled using a random effects model. RESULTS: Seven studies (872 limbs) were included for analysis. Included studies were of reasonable methodological quality. Ulcer healing rates were similar in each group (relative risk [RR], 1.07; 95% confidence interval [CI] 0.96-1.19; P = .23). Two studies reported no difference in mean time (days) to ulcer healing between groups (mean difference, -14.60; 95% CI, -34.57 to 5.38; P = .15; I2 = 0%; P = .56). Ulcer recurrence was significantly lower in the concomitant group (3.7% vs 44%) (RR, 0.21; 95% CI, 0.07- 0.65; P = .007; I2 = 43%; P = .17). Overall, there was no difference in disease severity measured at 12-month follow-up, with a weighted mean difference between groups of -0.88 (95% CI, -2.05 to 0.29; P = .14; I2 = 84%; P = .002). Quality of life was reported in only one study. The total number of perforator veins identified at follow-up duplex ultrasound was significantly lower in the concomitant group (22.4% vs 89%) compared with standard therapy (RR, 0.31; 95% CI, 0.19-0.53; P < .0001; I2 = 88%; P = .0002). There was no difference between groups for occlusion rates of treated great saphenous vein or incompetent perforators (RR, 2.22; 95% CI, 0.10-49.74; P = .61). Reported minor (RR, 0.98; 95% CI, 0.63-1.52; P = .92) and thrombotic complications (RR, 2.04; 95% CI, 0.59-6.99; P = .26) were similar between groups. CONCLUSIONS: Concomitant truncal and perforator surgery is comparable to standard therapy in terms of ulcer healing, safety, and efficacy. Meta-analysis suggests that concomitant treatment could significantly reduce ulcer recurrence rates, but included studies were subject to some biases and short follow-up. Concomitant treatment may be considered to prevent recurrence rather than improve ulcer healing.

Digital technology in informed consent for surgery: systematic review.

BACKGROUND: Informed consent is an ethical and legal requirement in healthcare and supports patient autonomy to make informed choices about their own care. This review explores the impact of digital technology for informed consent in surgery. METHODS: A systematic search of EBSCOhost (MEDLINE/CINAHL), Embase, Cochrane Central Register of Controlled Trials and Web of Science was performed in November 2021. All RCTs comparing outcomes of both digital and non-digital (standard) consent in surgery were included. Each included study underwent an evaluation of methodological quality using the Cochrane risk of bias (2.0) tool. Outcomes assessed included comprehension, level of satisfaction and anxiety, and feasibility of digital interventions in practice. RESULTS: A total of 40 studies, across 13 countries and 15 surgical specialties were included in this analysis. Digital consent interventions used active patient participation and passive patient participation in 15 and 25 studies respectively. Digital consent had a positive effect on early comprehension in 21 of 30 (70 per cent) studies and delayed comprehension in 9 of 20 (45 per cent) studies. Only 16 of 38 (42 per cent) studies assessed all four elements of informed consent: general information, risks, benefits, and alternatives. Most studies showed no difference in satisfaction or anxiety. A minority of studies reported on feasibility of digital technology in practice. CONCLUSION: Digital technologies in informed consent for surgery were found to have a positive effect on early comprehension, without any negative effect on satisfaction or anxiety. It is recommended that future studies explore the feasibility of these applications for vulnerable patient groups and busy surgical practice.

Rescue of Failed Aortic Repair with Fenestrated Endovascular Device.

INTRODUCTION: The incidence of failed endovascular (EVAR) and open repair (OR) is increasing. Redo aortic repair is required in 10% of patients. Extension of the proximal sealing zone above the visceral arteries to adequate, healthier thoracic aorta using a fenestrated graft (FEVAR) can rescue a failing repair. A custom-made device can treat proximal type 1a endoleaks or proximal dilatation post endovascular or open repair, respectively. The aim of this investigation was to present a single-centre experience with FEVAR for patients with a failing aortic repair. METHODS: A prospectively maintained database of FEVAR patients treated with a ZenithⓇ Fenestrated endovascular (ZFEN) device (Cook Medical LLC, Bloomington, Indiana, USA) was interrogated for individuals who had the device implanted as a rescue therapy after prior endovascular (EVAR) or open repair (OR). Statistical analysis was performed with SPSS v 25 software. RESULTS: Between January 1, 2011 and March 31, 2019, 17 ZFEN devices were implanted. 10 patients had a type 1a endoleak from a prior EVAR and 7 patients had proximal disease progression after prior OR. There were 12 males and 5 females, median age of 75 (interquartile range, IQR 7). 76.4% (n = 13) of patients had an American Society of Anaesthesiologists (ASA) grade of 3. Primary technical success was 70.5% (n = 12). Of the remainder, 4 cases (24%) had a type III endoleak at completion angiogram; of which, 2 patients (12%) required re-intervention within 30 days. One further case (6%) had primary assisted technical success as stenting of a flow limiting dissection flap in an iliac vessel was required. Peri-operative rate of deployment related complications and systemic complications were 5.8% (n = 1) and 35% (n = 6), respectively. Median length of hospital stay was 11 days (IQR 11). There was no mortality within the study follow up. Overall 30-day re-intervention rate was 23.5%. Overall survival was 92% at one year. CONCLUSION: FEVAR is a safe but technically challenging option for rescue of failing aortic repairs. These are a high-risk group of patients and this is reflected in the high post-operative morbidity rate. Technical success was high and 30-day mortality was low.

Hemodynamic improvement of a LUCAS 2 automated device by addition of an impedance threshold device in a pig model of cardiac arrest.

INTRODUCTION: The combination of the LUCAS 2 (L-CPR) automated CPR device and an impedance threshold device (ITD) has been widely implemented in the clinical field. This animal study tested the hypothesis that the addition of an ITD on L-CPR would enhance cerebral and coronary perfusion pressures. METHODS: Ten female pigs (39.0 ± 2.0 kg) were sedated, intubated, anesthetized with isofluorane, and paralyzed with succinylcholine (93.3 µg/kg/min) to inhibit the potential confounding effect of gasping. After 4 min of untreated ventricular fibrillation, 4 min of L-CPR+an active ITD or L-CPR+a sham ITD was initiated and followed by another 4 min of the alternative method of CPR. Systolic blood pressure (SBP), diastolic blood pressure (DBP), diastolic right atrial pressure (RAP), intracranial pressure (ICP), airway pressure, and end tidal CO2 (ETCO2) were recorded continuously. Data expressed as mean mmHg ± SD. RESULTS: Decompression phase airway pressure was significantly lower with L-CPR+active ITD versus L-CPR+sham ITD (-5.3 ± 2.2 vs. -0.5 ± 0.6; p<0.001). L-CPR+active ITD treatment resulted in significantly improved hemodynamics versus L-CPR+sham ITD: ETCO2, 35 ± 6 vs. 29 ± 7 (p=0.015); SBP, 99 ± 9 vs. 93 ± 15 (p=0.050); DBP, 24 ± 12 vs. 19 ± 15 (p=0.006); coronary perfusion pressure, 29 ± 8 vs. 26 ± 7 (p=0.004) and cerebral perfusion pressure, 24 ± 13 vs. 21 ± 12 (p=0.028). CONCLUSIONS: In pigs undergoing L-CPR the addition of the active ITD significantly reduced intrathoracic pressure and increased vital organ perfusion pressures.

Development of a sea anemone toxin as an immunomodulator for therapy of autoimmune diseases.

Electrophysiological and pharmacological studies coupled with molecular identification have revealed a unique network of ion channels--Kv1.3, KCa3.1, CRAC (Orai1 + Stim1), TRPM7, Cl(swell)--in lymphocytes that initiates and maintains the calcium signaling cascade required for activation. The expression pattern of these channels changes during lymphocyte activation and differentiation, allowing the functional network to adapt during an immune response. The Kv1.3 channel is of interest because it plays a critical role in subsets of T and B lymphocytes implicated in autoimmune disorders. The ShK toxin from the sea anemone Stichodactyla helianthus is a potent blocker of Kv1.3. ShK-186, a synthetic analog of ShK, is being developed as a therapeutic for autoimmune diseases, and is scheduled to begin first-in-man phase-1 trials in 2011. This review describes the journey that has led to the development of ShK-186.

Lower-limb vascular imaging with acoustic radiation force elastography: demonstration of in vivo feasibility.

Acoustic radiation force impulse (ARFI) imaging characterizes the mechanical properties of tissue by measuring displacement resulting from applied ultrasonic radiation force. In this paper, we describe the current status of ARFI imaging for lower-limb vascular applications and present results from both tissue-mimicking phantoms and in vivo experiments. Initial experiments were performed on vascular phantoms constructed with polyvinyl alcohol for basic evaluation of the modality. Multilayer vessels and vessels with compliant occlusions of varying plaque load were evaluated with ARFI imaging techniques. Phantom layers and plaque are well resolved in the ARFI images, with higher contrast than B-mode, demonstrating the ability of ARFI imaging to identify regions of different mechanical properties. Healthy human subjects and those with diagnosed lower-limb peripheral arterial disease were imaged. Proximal and distal vascular walls are well visualized in ARFI images, with higher mean contrast than corresponding B-mode images. ARFI images reveal information not observed by conventional ultrasound and lend confidence to the feasibility of using ARFI imaging during lower-limb vascular workup.

In vivo guidance and assessment of liver radio-frequency ablation with acoustic radiation force elastography.

The initial results from clinical trials investigating the utility of acoustic radiation force impulse (ARFI) imaging for use with radio-frequency ablation (RFA) procedures in the liver are presented. To date, data have been collected from 6 RFA procedures in 5 unique patients. Large displacement contrast was observed in ARFI images of both pre-ablation malignancies (mean 7.5 dB, range 5.7-11.9 dB) and post-ablation thermal lesions (mean 6.2 dB, range 5.1-7.5 dB). In general, ARFI images provided superior boundary definition of structures relative to the use of conventional sonography alone. Although further investigations are required, initial results are encouraging and demonstrate the clinical promise of the ARFI method for use in many stages of RFA procedures.

Challenges and implementation of radiation-force imaging with an intracardiac ultrasound transducer.

Intracardiac echocardiography (ICE) has been demonstrated to be an effective imaging modality for the guidance of several cardiac procedures, including radiofrequency ablation (RFA). However, assessing lesion size during the ablation with conventional ultrasound has been limited, as the associated changes within the B-mode images often are subtle. Acoustic radiation force impulse (ARFI) imaging is a promising modality to monitor RFAs as it is capable of visualizing variations in local stiffnesses within the myocardium. We demonstrate ARFI imaging with an intracardiac probe that creates higher quality images of the developing lesion. We evaluated the performance of an ICE probe with ARFI imaging in monitoring RFAs. The intracardiac probe was used to create high contrast, high resolution ARFI images of a tissue-mimicking phantom containing stiffer spherical inclusions. The probe also was used to examine an excised segment of an ovine right ventricle with a RFA-created surface lesion. Although the lesion was not visible in conventional B-mode images, the ARFI images were able to show the boundaries between the lesion and the surrounding tissue. ARFI imaging with an intracardiac probe then was used to monitor cardiac ablations in vivo. RFAs were performed within the right atrium of an ovine heart, and B-mode and ARFI imaging with the intracardiac probe was used to monitor the developing lesions. Although there was little indication of a developing lesion within the B-mode images, the corresponding ARFI images displayed regions around the ablation site that displaced less.

The impact of physiological motion on tissue tracking during radiation force imaging.

The effect of physiological motion on the quality of radiation force elasticity images has been investigated. Experimental studies and simulated images were used to investigate the impact of motion effects on image quality metrics over a range of clinically realistic velocity and acceleration magnitudes. Evaluation criteria included motion filter effectiveness, image signal-to-noise ratio (SNR) and the contrast-to-noise ratio (CNR) of a stiff inclusion embedded in a homogeneous background material. Two transmit frequencies (2.5 and 4.4 MHz) were analyzed and contrasted in terms of image quality over a range of target motions. Results indicate that situations may exist where liver and cardiac motion magnitudes lead to poor image quality, but optimized transducer orientations may help suppress motion artifacts if some a priori information concerning target motion characteristics is known. In the presence of significant target motion, utilizing a lower transmit frequency can improve SNR and CNR in elasticity images.

Frame rate considerations for real-time abdominal acoustic radiation force impulse imaging.

With the advent of real-time Acoustic Radiation Force Impulse (ARFI) imaging, elevated frame rates are both desirable and relevant from a clinical perspective. However, fundamental limitations on frame rates are imposed by thermal safety concerns related to incident radiation force pulses. Abdominal ARFI imaging utilizes a curvilinear scanning geometry that results in markedly different tissue heating patterns than those previously studied for linear arrays or mechanically-translated concave transducers. Finite Element Method (FEM) models were used to simulate these tissue heating patterns and to analyze the impact of tissue heating on frame rates available for abdominal ARFI imaging. A perfusion model was implemented to account for cooling effects due to blood flow and frame rate limitations were evaluated in the presence of normal, reduced and negligible tissue perfusions. Conventional ARFI acquisition techniques were also compared to ARFI imaging with parallel receive tracking in terms of thermal efficiency. Additionally, thermocouple measurements of transducer face temperature increases were acquired to assess the frame rate limitations imposed by cumulative heating of the imaging array. Frame rates sufficient for many abdominal imaging applications were found to be safely achievable utilizing available ARFI imaging techniques.

Acoustic radiation force impulse imaging of the abdomen: demonstration of feasibility and utility.

The feasibility of utilizing acoustic radiation force impulse (ARFI) imaging to assess the mechanical properties of abdominal tissues was investigated. The thermal safety of the technique was also evaluated through the use of finite element method models. ARFI imaging was shown to be capable of imaging abdominal tissues at clinically realistic depths. Correspondence between anatomical structures in B-mode and ARFI images was observed. ARFI images showed similar tumor contrast when compared with B-mode images of ex vivo abdominal cancers. Finite element method models and in vitro measurements confirmed the thermal safety of ARFI imaging at depth. ARFI imaging is inexpensive, safe and convenient and is a promising modality for use in abdominal imaging.

Acoustic radiation force impulse imaging of myocardial radiofrequency ablation: initial in vivo results.

Acoustic radiation force impulse (ARFI) imaging techniques were used to monitor radiofrequency (RF) ablation of ovine cardiac tissue in vivo. Additionally, ARFI M-mode imaging methods were used to interrogate both healthy and ablated regions of myocardial tissue. Although induced cardiac lesions were not visualized well in conventional B-mode images, ARFI images of ablation procedures allowed determination of lesion location, shape, and relative size through time. The ARFI M-mode images were capable of distinguishing differences in behavior through the cardiac cycle between healthy and damaged tissue regions. As conventional sonography is often used to guide ablation catheters, ARFI imaging, which requires no additional equipment, may be a convenient modality for monitoring lesion formation in vivo.

Acoustic radiation force impulse imaging of thermally- and chemically-induced lesions in soft tissues: preliminary ex vivo results.

The ability of acoustic radiation force impulse (ARFI) imaging to visualize thermally- and chemically-induced lesions in soft tissues was investigated. Lesions were induced in freshly excised bovine liver samples. Chemical lesions were induced via the injection of formaldehyde and thermal lesions were created using a radiofrequency (RF) ablation system. Although conventional sonography was unable to visualize induced lesions, ARFI imaging was capable of monitoring lesion size and boundaries. Agreement was observed between lesion size in ARFI images and in results from pathology. The fact that ARFI imaging requires no additional equipment aside from that needed for conventional ultrasonic imaging makes it a promising modality for monitoring lesion development in situations where sonography is already involved as a guiding mechanism, such as in procedures requiring precise catheter placement.