Visceral Perfusion Research Articles

Urgent hybrid repair of a symptomatic dissection-related type ii thoracoabdominal aortic aneurysms.

Emergency repair of type II thoraco-abdominal aortic aneurysms is burdened by high perioperative morbidity and mortality. We report the case of a symptomatic type II post-dissection thoraco-abdominal aortic aneurysm that was treated by mean of a hybrid technique. The repair was carried out through two stages. In the first stage, we deployed two imbricated stent grafts in the descending thoracic aorta. A left carotid to left subclavian artery by-pass was preemptively performed in order to obtain a proper proximal landing zone and as part of the spinal cord protective maneuvers. The endovascular first stage was effective in obtaining proximal sealing but, as expected, did not prevent distal reperfusion of the aneurysmatic false lumen. Few hours later, we moved on to the second stage in which we repaired the aneurysmal distal thoracic and abdominal aortic segment by mean of a multibranched synthetic graft. The repair was carried out through a left thoracophrenolaparotomy in the VII intercostal space. A left passive arterial by-pass and selective cold renal and warm visceral perfusion were adopted in order to provide organ protection. Technical success was achieved and radiologically confirmed. The patient experienced a mild postoperative paraplegia, which almost completely regressed after a neuro-motor rehabilitation program.

440. QUANTIFICATION OF FLUORESCENCE ANGIOGRAPHY FOR ESOPHAGEAL PERFUSION ASSESSMENT: MEASURING AGREEMENT BETWEEN TWO SOFTWARE ALGORITHMS

Abstract Background Indocyanine green fluorescence angiography (ICG-FA) may reduce perfusion related complications after esophagectomy with gastric conduit reconstruction. Software implementations for quantifying ICG-FA are emerging to overcome a subjective interpretation of the technology. Comparison between quantification algorithms is needed to judge its external validity. This study aimed to measure the agreement for esophageal perfusion assessment between two independently developed quantification software implementations. Methods This retrospective cohort analysis included standardized ICG-FA video recordings of patients who underwent esophagectomy with gastric conduit reconstruction between August 2020 until February 2022. Recordings were analysed by two quantification software implementations: AMS and CPH. The quantitative parameter used to measure visceral perfusion was the normalized maximum slope derived from fluorescence time curves. The agreement between AMS and CPH was evaluated in a Bland-Altman analysis. The relation between the intraoperative measurement of perfusion and the incidence of anastomotic leakage was determined for both software implementations. Results Seventy pre-anastomosis ICG-FA recordings were included in the study. The Bland-Altman analysis indicated a mean relative difference of +58.2% in the measurement of the normalized maximum slope when comparing the AMS software to CPH. The agreement between AMS and CPH deteriorated as the magnitude of the measured values increased, revealing a proportional (linear) bias (R2 = 0.512, p < .001). Neither the AMS nor the CPH measurements of the normalized maximum slope held a significant relationship with the occurrence of anastomotic leakage (median of 0.081 versus 0.074, p = 0.32 and 0.041 vs 0.042, p = 0.51, respectively). Divergent approaches in maximum slope determination and raw signal filtering were identified as contributing factors to the differences in outcome. Conclusion This is the first study to demonstrate technical differences in software implementations that can lead to discrepancies in ICG-FA quantification in human clinical cases. The possible variation among software-based quantification methods should be considered when interpreting studies that report quantitative ICG-FA parameters and derived thresholds, as there may be a limited external validity.

Quantification of fluorescence angiography for visceral perfusion assessment: measuring agreement between two software algorithms

BackgroundIndocyanine green fluorescence angiography (ICG-FA) may reduce perfusion-related complications of gastrointestinal anastomosis. Software implementations for quantifying ICG-FA are emerging to overcome a subjective interpretation of the technology. Comparison between quantification algorithms is needed to judge its external validity. This study aimed to measure the agreement for visceral perfusion assessment between two independently developed quantification software implementations.MethodsThis retrospective cohort analysis included standardized ICG-FA video recordings of patients who underwent esophagectomy with gastric conduit reconstruction between August 2020 until February 2022. Recordings were analyzed by two quantification software implementations: AMS and CPH. The quantitative parameter used to measure visceral perfusion was the normalized maximum slope derived from fluorescence time curves. The agreement between AMS and CPH was evaluated in a Bland–Altman analysis. The relation between the intraoperative measurement of perfusion and the incidence of anastomotic leakage was determined for both software implementations.ResultsSeventy pre-anastomosis ICG-FA recordings were included in the study. The Bland–Altman analysis indicated a mean relative difference of + 58.2% in the measurement of the normalized maximum slope when comparing the AMS software to CPH. The agreement between AMS and CPH deteriorated as the magnitude of the measured values increased, revealing a proportional (linear) bias (R2 = 0.512, p < 0.001). Neither the AMS nor the CPH measurements of the normalized maximum slope held a significant relationship with the occurrence of anastomotic leakage (median of 0.081 versus 0.074, p = 0.32 and 0.041 vs 0.042, p = 0.51, respectively).ConclusionThis is the first study to demonstrate technical differences in software implementations that can lead to discrepancies in ICG-FA quantification in human clinical cases. The possible variation among software-based quantification methods should be considered when interpreting studies that report quantitative ICG-FA parameters and derived thresholds, as there may be a limited external validity.

Liver and cardiovascular diseases: a two-way relationship. Review

Diseases of the liver and cardiovascular system often accompany each other. It is pathogenetically prudent to divide the causes of concomitant diseases of the heart and liver into four groups: heart diseases that affect the liver; liver diseases that contribute to the development of heart pathology; alterations in the cardiovascular system and liver that have a common cause; and concomitant diseases of the heart and liver that have multiple causes. Congestive hepatopathy develops as a result of right ventricular heart failure of various etiology, including constrictive pericarditis, tricuspid regurgitation, cardiomyopathy, and cor pulmonale. Venous congestion predisposes to liver injury via three main pathogenetic mechanisms: insufficient hepatic blood flow, decreased arterial oxygen saturation, and increased hepatic venous pressure. Ischemic hepatitis may develop under conditions of severe, protracted hypotension, which impairs visceral perfusion and predisposes to hypoxemia. Hepatopulmonary syndrome is a clinical syndrome characterized by a distinct symptom complex, which may include pathological arteriovenous shunting in the pulmonary vessels, arterial hypoxemia, liver disease, and/or portal hypertension. Portopulmonary hypertension is pulmonary arterial hypertension caused by portal hypertension in the absence of an alternative etiology. Hemochromatosis, chronic alcoholism, and amyloidosis are the most common causes of concomitant heart and liver diseases with a common etiology. Determining the pathogenetic variant of concomitant diseases is essential for deciding on treatment strategies, particularly surgical intervention, or heart or liver transplantation.

OGC O08 Quantification of fluorescence angiography for visceral perfusion assessment in gastric conduit reconstruction: measuring agreement between two software algorithms

Abstract Background Building evidence suggests that fluorescence angiography is capable of reducing anastomotic leakage rates. Many software-based quantification algorithms have been developed aiming to obtain an objective measure for intraoperative visceral perfusion at the anastomotic site. Validation and comparison of these models in the current literature is scarce. The aim of this study was to measure agreement between two independently developed software algorithms for the quantitative assessment of visceral perfusion using indocyanine green fluorescence angiography. Methods 81 video recordings from patients who underwent fluorescence angiography-guided Ivor Lewis esophagectomy with gastric conduit reconstruction between August 2020 and February 2022 were available for analysis. In this dataset, we standardized patient, theatre, camera and imaging display variables. Recordings were analyzed retrospectively based on intraoperatively selected regions of interest using two software based-quantification algorithms (AMS and CPH). Quantitative parameters derived from the fluorescence time curve (FTC) were recorded. The comparison focused on the predefined primary outcome variable for quantitative perfusion assessment "normalized maximum slope". Agreement between the two software algorithms was evaluated in a Bland-Altman analysis. Quantitative parameters in patients with anastomotic leakage were compared to those without. Results Out of 81 video recordings, 70 could be processed using both algorithms. The output values for the normalized maximum slope from the AMS and the CPH software held a moderate-to-strong correlation in a linear regression model (R-squared: 0.544, p&amp;lt;0.001). The Bland-Altman plot indicated a mean±SD difference of 0.037±0.018 arbitrary units for the normalized maximum slope, with significant differences between the two software measurements (p&amp;lt;0.001). Proportional bias was observed using linear regression in the Bland-Altman plot (R-squared=0.715, p&amp;lt;0.001). Disparities between the two measurement methods became proportionally larger among higher mean values. Neither of the two software methods showed a significant difference in perfusion measurement between the anastomotic leakage and no leakage groups (p=0.32 and p=0.51). Differences in signal processing, such as smoothing techniques and window selection, were identified as potential factors contributing to the disparity in outcomes. Conclusions The two software-based quantification methods for visceral perfusion demonstrated significant differences. Varying agreement among quantification methods should be considered while interpreting studies that report quantitative parameters and derived thresholds for clinical endpoints, as there may be a limited external validity.

Aortic Remodeling Following Hybrid Arch Repair for Complex Arch and Proximal Descending Thoracic Aortopathies

Hybrid aortic arch repair involves debranching of the great vessels to create a zone 0 proximal landing zone for simultaneous or staged thoracic endovascular aortic repair (TEVAR) as a less invasive therapy for complex arch and descending thoracic aortopathies. Data on thoracoabdominal aortic remodeling following hybrid arch repair remains scarce. We aimed to evaluate short-term remodeling of the thoracoabdominal aorta following hybrid arch repair. All patients (n = 38) undergoing hybrid arch repair with planned zones 0 to 5 TEVAR from January 2020 to March 2022 were retrospectively reviewed. Computed tomography angiography scans preoperatively, after TEVAR, and at the 3- to 6-month follow-up were analyzed for thoracoabdominal aorta remodeling. Aortic true lumen diameter (TLD) for dissections and full lumen diameter for aneurysms were recorded at 12 anatomical levels: left subclavian artery, tracheal carina, left inferior pulmonary vein, inferior left atrium, diaphragm, celiac trunk, superior mesenteric artery, renal arteries, aortic bifurcation, and common iliac arteries. Visceral vessel origin from true/false lumen and extent of false lumen thrombosis were assessed. Mean change in aortic TLD was calculated at every level and paired-samples t test was used to compare means. Of 38 patients, 37 had follow-up imaging at a mean duration of 6 months (mean age, 57.9 ± 10.0 years; 30 males [78.9%]) and one (2.6%) mortality (Table). Four (10.5%) presented with aneurysms (0, 3), 26 (68.4%) with type A aortic dissection (0, 3), and 8 (21.1%) with type B aortic dissection (1, 10). In aneurysm patients (n = 4), there was one postoperative death (2.6%) due to cardiac arrest before staged TEVAR; the remaining three had stable aneurysm sacs without endoleak at last follow-up. For dissection patients, at a mean follow-up of 6 months, there was significant increase in the mean TLD at each level (P < .05), except zones 9 and 10. The largest increase in mean TLD was observed at the left subclavian artery (+5.19 mm; 95% confidence interval [CI], 2.63-7.76), tracheal carina (+6.78 mm; 95% CI, 3.04-10.53), and lower left atrium (+4.49 mm; 95% CI, 2.01-6.97). The left renal artery was the most common vessel originating from the false lumen (14 [36.8%] pre- and post-TEVAR); followed by the right renal artery (7 [18.4%] pre-TEVAR and 5 [13.2%] post-TEVAR). Visceral perfusion remained intact following TEVAR in all patients. False lumen thrombosis to distal zone 5 was observed in 100% of the dissection patients. Hybrid arch repair with zone 0 to 5 TEVAR provides adequate aneurysm exclusion and positive aortic remodeling down to zone 8 in the short term with improved TLD and high rate of false lumen thrombosis. When involved, zones 9 to 11 may require adjunctive or alternative branched or fenestrated strategies for total aortic remodeling and complete false lumen obliteration.TableSummary of included patients and measurements at various anatomic levelsVariableNo. of patients (%); n = 38Patient characteristics Age, years57.9 ± 10.0 Male30 (78.9) Diabetes mellitus11 (28.9) Hypertension35 (92.1) Dyslipidemia19 (50.0) Cerebrovascular disease4 (10.5) Dialysis1 (2.6) Chronic obstructive pulmonary disease7 (18.4) Smoking history22 (57.9) Prior coronary artery bypass grafting3 (7.9) Aortic aneurysm4 (10.5) Type A aortic dissection26 (68.4) Type B aortic dissection8 (21.1) Prior valve surgery10 (26.3) Mortality1 (2.6)Aortic remodeling dataLevelPreoperative true lumen measurements, mmPost-TEVAR true lumen measurements (mean follow-up 6 months), mmRemodeling over mean follow-up of 6 monthsMinMaxMean ± SDVessel origin from false lumenFalse lumen partial thrombosisFalse lumen full thrombosisMinMaxMean ± SDVessel origin from false lumenFalse lumen partial thrombosisFalse lumen full thrombosisMean Change (95% CI) [% change]P valueLeft subclavian artery11.248.322.25 ± 8.83---15.938.427.44 ± 5.33---5.19 (2.63-7.76) [+23.3%].001*Carina3.460.919.78 ± 11.05---3.340.126.59 ± 7.28---6.78 (3.04-10.53) [+34.3%].001*LIPV6.567.317.45 ± 10.61---7.93623.16 ± 6.31---4.27 (0.85-7.69) [+24.5%].016*Left atrium4.966.216.89 ± 11.03---5.461.221.33 ± 9.30---4.49 (2.01-6.97) [+26.6%].001*Diaphragm6.634.715.75 ± 7.15---6.549.119.03 ± 8.22---3.28 (1.53-5.04) [+20.9%].001*Celiac trunk2.828.113.92 ± 6.574 (10.5)25 (65.8)0 (0.0)5.928.915.49 ± 6.204 (10.5)14 (36.8)2 (5.3)2.57 (0.86-4.27) [+18.4%].005*SMA3.427.113.77 ± 5.963 (7.9)24 (63.2)0 (0.0)6.330.114.94 ± 5.673 (7.9)17 (44.7)1 (2.6)1.17 (0.20-2.15) [+8.5%].020*RRA3.126.313.08 ± 6.147 (18.4)24 (63.2)0 (0.0)6.728.614.46 ± 5.645 (13.2)13 (34.2)1 (2.6)1.38 (0.18-2.58) [+10.6%].025*LRA3.130.712.78 ± 6.4714 (36.8)22 (57.9)0 (0.0)6.328.613.80 ± 5.4614 (36.8)13 (34.2)2 (5.3)1.02 (0.02-2.02) [+8.0%].046*Aortic bifurcation7.328.114.06 ± 5.83---7.830.114.45 ± 4.99---0.39 (−0.83 – 1.62) [+2.8%].518RCIA3.517.510.82 ± 3.76---2.717.710.44 ± 3.46---−0.38 (−1.36 – 0.61) [-3.5%].443LCIA3.315.610.28 ± 3.72---3.616.410.67 ± 3.63---0.28 (−0.29 – 0.86) [+2.8%].317LCIA, left common iliac artery; LIPV, left inferior pulmonary vein; LSCA, left subclavian artery; RRA, right renal artery; LRA, left renal artery; RCIA, right common iliac artery; SD, standard deviation SMA, superior mesenteric artery; TEVAR, thoracic endovascular aortic repair. 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Fluid–structure interaction simulation of visceral perfusion and impact of different cannulation methods on aortic dissection

Hemodynamics in aortic dissection (AD) is closely associated with the risk of aortic aneurysm, rupture, and malperfusion. Altered blood flow in patients with AD can lead to severe complications such as visceral malperfusion. In this study, we aimed to investigate the effect of cannulation flow on hemodynamics in AD using a fluid–structure interaction simulation. We developed a specific-idealized AD model that included an intimal tear in the descending thoracic aorta, a re-entry tear in the left iliac artery, and nine branches. Two different cannulation methods were tested: (1) axillary cannulation (AC) only through the brachiocephalic trunk and (2) combined axillary and femoral cannulation (AFC) through the brachiocephalic trunk and the right common iliac artery. AC was found to result in the development of a pressure difference between the true lumen and false lumen, owing to the difference in the flow rate through each lumen. This pressure difference collapsed the true lumen, disturbing blood flow to the celiac and superior mesenteric arteries. However, in AFC, the pressure levels between the two lumens were similar, and no collapse occurred. Moreover, the visceral flow was higher than that in AC. Lastly, the stiffness of the intimal flap affected the true lumen's collapse.

Fluorescence-guided surgery: National trends in adoption and application in pediatric surgery

BackgroundFluorescence-guided surgery (FGS) with indocyanine green (ICG) is a rapidly diffusing surgical innovation, but its utilization in pediatrics remains unknown. We present a cross-sectional descriptive analysis of trends from a national database. MethodsThe Pediatric Health Information System (PHIS) database was queried for patient encounters between January 2016 and July 2021 with an associated ICG administration within 3 days prior to surgery. All procedure codes from each encounter were reviewed by two surgeons to determine the most likely associated FGS procedure and assign an operative category. Results1270 encounters were identified from 38 participating hospitals. The mean patient age (SD) was 8.3 (6.4) years, 54.5% were male, 63.8% were white, and 30.1% were Hispanic. The most common categories for ICG use were neurosurgery (21.3%), biliary (18.3%), perfusion (14.8%), urology (12.5%), gastrointestinal (10.8%), ophthalmology (8.8%), and thoracic (5.6%). Utilization over time increased for some categories (thoracic, visceral perfusion, and neurological procedures) or remained stable for other categories. Overall ICG utilization has increased in 2020 (n = 314) compared to 2016 (N = 83). The number of centers utilizing ICG has also increased from 14 hospitals in 2016 to 29 hospitals in 2020 though adoption remains unevenly distributed, with 5 high-utilization hospitals accounting for 56.8% of all ICG FGS cases. ConclusionICG is being used across a wide variety of pediatric surgical disciplines. Trends over time show increasingly frequent adoption across the country, with a few high-volume centers driving the innovation. Fluorescence-guided surgery is commercially available and is becoming more commonplace for pediatric surgeons. Dedicated efforts will now be needed to assess outcomes using this promising technology. Level of evidenceLevel IV. Study typeRetrospective study.

The application of modular multifunctional left heart bypass circuit system integrated with ultrafiltration in thoracoabdominal aortic aneurysm repair.

Open thoracoabdominal aortic aneurysm (TAAA) repair is a complex and challenging operation with a high incidence of serious complications, and high perioperative mortality and morbidity. Left heart bypass (LHB) is a circulatory support system used to perfuse the distal aorta during TAAA operation, and the advantages of LHB include guaranteeing distal perfusion, reducing the use of heparin, and diminishing the risk of bleeding and postoperative neurological deficits. In China, the circuit for TAAA repair is deficient, and far from the perfusion requirements. We designed a modular multifunctional LHB circuit for TAAA repair. The modular circuit consisted of cannulation pipelines, functional consumables connection pipelines, and accessory pipelines. The accessory pipelines make up lines for selective visceral perfusion and kidney perfusion, suckers and rapid infusion. The circuit can be assembled according to surgical requirements. The ultrafilter and heat exchanger are integrated into the circuit to fulfill the basic demands of LHB. The LHB circuit also has pipelines for selective visceral perfusion to the celiac artery and superior mesenteric artery and renal perfusion pipelines. Meanwhile, the reserved pipelines facilitate the quick switch from LHB to conventional cardiopulmonary bypass (CPB). The reserved pipelines reduce the time of reassembling the CPB circuit. Moreover, the rapid infusion was integrated into the LHB circuit, which can rapid infusion when massive hemorrhage during the open procedures such as exposure and reconstruction of the aorta. The ultrafiltration can diminish the consequent hemodilution of hemorrhage and rapid infusion. A hemoperfusion cartridge also can be added to reduce the systemic inflammatory during operation. The circuit can meet the needs of LHB and quickly switch to conventional CPB. No oxygenator was required during LHB, which reduce the use of heparin and reduce the risk of bleeding. The heat exchanger contributes to temperature regulation; ultrafiltration, arterial filter, and rapid-infusion facilitated the blood volume management and are useful to maintain hemodynamic stability. This circuit made the assembly of the LHB circuit more easily, and more efficient, which may contribute to the TAAA repair operation performed in lower volume centers easily. 26 patients who received TAAA repair under the modular multifunctional LHB from January 2018-March 2022 were analyzed, and we achieved acceptable clinical outcomes. The in-hospital mortality and 30-day postoperative mortality were 15.4%, and the postoperative incidences of paraparesis (4%), stroke (4%), and AKI need hemodialysis (12%) were not particularly high, based on the limited patients sample size in short research period duration.

Invivo evaluation of a new hybrid graft using retrograde visceral perfusion for thoracoabdominal aortic repair in an animal model.

ObjectivesThe SPIDER technique for hybrid thoracoabdominal aortic aneurysm repair can avoid thoracotomy and extracorporeal circulation. To improve technical feasibility and safety, the new Thoracoflo graft, consisting of a proximal stent graft connected to a 7-branched abdominal prosthesis, was evaluated in a pig model for technical feasibility testing, before implantation in humans.MethodsRetroperitoneal exposure of the infradiaphragmatic aorta, including visceral and renal arteries, was performed in 7 pigs (75-85 kg). One iliac branch was temporarily attached to the distal aorta to maintain retrograde visceral and antegrade iliac perfusion after deployment of the thoracic stent graft segment (SPIDER technique). The proximal stent-grafted segment was deployed in the thoracic aorta via direct aortic puncture over the wire without fluoroscopy. The graft was deaired before flow via the iliac side branch to the visceral and iliac arteries was established. Visceral, renal, and lumbar arteries were subsequently sutured to the corresponding side branches of the graft. Technical feasibility, operating and clamping time, blood flow, and tissue perfusion in the related organs were evaluated before implantation and after 3 and 6 hours using transit-time flow measurement and fluorescent microspheres. Final angiography or postprocedural computed tomography angiography were performed.ResultsOver-the-wire graft deployment was successful in 6 animals without hemodynamic alteration (P = n.s.). In 1 pig, the proximal stent graft section migrated as the guidewire was not removed, as recommended, before release of the proximal fixation wire. Angiography and computed tomography scan confirmed successful graft implantation and transit-time flow measurement confirmed good visceral and iliac blood flow. Fluorescent microspheres confirmed good spinal cord perfusion.ConclusionsOver-the-wire implantation of the Thoracoflo graft using the SPIDER technique is feasible in a pig model. No fluoroscopy was required. For safe implantation, it is mandatory to follow the single steps of implantation.

Type B aortic dissection residual after proximal aortic repair: an innovative open surgical approach in patients not eligible for endovascular treatment.

Residual type B aortic dissection (R-TBAD) is a challenging kind of disease affecting an increasing number of patients. Management of R-TBAD has not been specifically addressed in current literature and many of those patients are not eligible for endovascular treatment. Aim of the study was to evaluate the efficacy and feasibility of a specifically conceived procedure the "saguaro branched graft technique" to treat R-TBAD distal to a proximal stent-graft. Data of patients treated between 2015 and 2019 were prospectively collected and retrospectively analyzed. Indication for surgery was R-TBAD with chronic malperfusion, aortic enlargement >55 mm or rapid growth, and symptomatic aortic enlargement. A Dacron graft with four branches has been tailored on the back table by implanting two bifurcated grafts to a tube or bifurcated graft. After left thoracoabdominal incision the proximal endograft has been used as a solid starting point for the distal branched graft. Sequential revascularization of the visceral vessels was performed step by step by suturing each artery outside the aneurysm before opening the distal aorta, while a continued retrograde aortic and visceral perfusion was maintained by a left pump atrio-femoral bypass. After that all visceral branches had been regularly perfused from above, the thoraco-abdominal aorta was open and repaired. Outcome measures were 30-day mortality and 30-day major complications as were long-term all-cause mortality, aorta-related mortality, reintervention and patency rates of the branches. Thirteen patients with R-TBAD were treated during the study period. Indication for surgery was chronic malperfusion in one patient (7.7%), aortic enlargement >55 mm or rapid growth in 9 patients (69.2%), persistent pain with aortic enlargement ≥50 mm in 3 patients (23.1%). All patients were considered not eligible for endovascular repair. At 30-days no deaths or re-interventions occurred and major complications including acute cardiovascular events and renal function impairment were not reported; one patient (7.7%) developed postoperative paraplegia. At a mean follow-up period of 19.6±10.2 (range, 8-48) months, reintervention and mortality rates were null. Visceral malperfusion and late-onset renal failure were not reported, and all visceral branches were still patent. Despite the potential high risk of open surgery, the "saguaro branched graft technique" appears to be a safe surgical solution for R-TBAD.

The anchor point algorithm: A morphometric analysis of anatomic landmarks to guide placement of temporary aortic Rescue stent grafts for noncompressible torso hemorrhage.

Noncompressible hemorrhage remains a high-mortality injury, which requires rapid damage control within minutes to avoid exsanguination. Retrievable stent grafts offer perfusion preserving hemorrhage damage control, and yet algorithms for device selection and positioning are lacking for an anatomically diverse human population. We hypothesized that easily acquired external measurements could be used to rapidly triage patients to receive one of several presized stents and that these metrics may further predict a single target on the aorta by which to optimize both mesenteric perfusion and aortic hemorrhage control. Metrics were acquired from computed tomography imaging of 203 male and female patients aged 18 to 50 years. Algorithms for metric based triage and stent sizing were examined against the cohort for effectiveness. Linear regression was used to predict a single target on the aorta for alignment of a multitiered stent. Next, the relationship of the anchor point to the palpable xiphoid was determined. Clavicle to pubis measurements correlated with aortic length and was used to triage patients to one of three stent grafts. Stents for each triage group were sized to achieve >75% coverage of aortic Zones 1 and 3 in most patients while preserving carotid and visceral perfusion. A metric/sex-based equation that predicts the location of the superior mesenteric artery relative to the palpable xiphoid was derived. By alignment of a single point on the stent with this target, known as the anchor point, the remainder of the stent can be rapidly deployed while minimizing coverage of critical branches. When applied back to the cohort, only 10.4% had potential serious branch coverage events predicted. Simple anatomic metrics offer rapid triage in this study population to one of three presized stent grafts and predict the location of key vascular branches. Confirmatory human trials will be essential to demonstrate safety and effectiveness of this approach. Prognostic/Epidemiological; Level IV.

The Features of Stomach Vascularisation Pattern and Their Impact on Oesophageal Reconstruction with a Gastric Pull-up.

Regardless of the reconstruction surgery used, the fundamental concepts of visceral reconstruction are based on the vascular support needed for the substituting graft. The vascular factor is the main element of any reconstruction technique, as an underlying condition for the visceral material stretch and, along with other factor, for the suture safety. In the case of the stomach, a consistent vascular flow and the minimal vascular anatomy variations are the first theoretical argument. A second argument is based on the intraparietal vascular network features allowing for supplementing visceral perfusion as the blood flow is stopped in one or more pediculi. Graft hypoperfusion is, however, a potential cause of failure, and the most frequently invoked complication is, therefore, a high risk of anastomosis fistulae. A series of modern techniques - arteriography data for the pre-operative vascular reconstruction or Doppler laser fluorometry intraoperative assessments, graft oximetry, laser speckle (spot) scan or the use of indocyanine green staining (ICG) - represent methods of early determination of the gastric graft perfusion/microperfusion quality used in reducing such risks. The doubts regarding the gastric perfusion mandate the use of vascular augmentation techniques. If such techniques are not used, the final outcome is uncertain and difficult to correct.

Thoracoabdominal Aneurysms—Operative Steps for Crawford Extent II Repair

Open surgical repair remains the gold standard for treatment of thoracoabdominal aortic aneurysms (TAAA), aiming to replace the whole length of the diseased distal aorta while protecting the spinal cord and visceral organs to limit ischemia-related complications. This surgery carries significant risks, including death, paraplegia, renal failure requiring permanent dialysis and respiratory complications leading to prolonged ICU stay, but these still outweigh the natural history of TAAA with conservative treatment. We describe in detail our current approach to open extent II TAAA repair by a step-by-step illustration of the technique and the surgical adjuncts. We routinely use left heart bypass with mild passive hypothermia (34°C), cerebrospinal fluid drainage, sequential aortic cross-clamping, monitoring of motor-evoked potentials (MEPs), cerebral, paraspinal and lower limbs oxygen saturations by near-infrared spectrometry as well as selective visceral perfusion via the coeliac, superior mesenteric and renal arteries. We advocate for individual branch reimplantation using a branched thoracoabdominal graft and when possible and we selectively reattach one or more pairs of the lower thoracic intercostal arteries and/or high lumbar arteries, even in absence of a significant reduction on the MEPs signal. The distal anastomosis is usually constructed above the aortic bifurcation and occasionally to each iliac separately using a bifurcated graft. Favorable early outcomes and a durable repair can be achieved at experienced high-volume centers, with standardized pre-operative selection and multidisciplinary team based intraoperative and postoperative management of these patients. Open surgical repair remains the gold standard for treatment of thoracoabdominal aortic aneurysms (TAAA), aiming to replace the whole length of the diseased distal aorta while protecting the spinal cord and visceral organs to limit ischemia-related complications. This surgery carries significant risks, including death, paraplegia, renal failure requiring permanent dialysis and respiratory complications leading to prolonged ICU stay, but these still outweigh the natural history of TAAA with conservative treatment. We describe in detail our current approach to open extent II TAAA repair by a step-by-step illustration of the technique and the surgical adjuncts. We routinely use left heart bypass with mild passive hypothermia (34°C), cerebrospinal fluid drainage, sequential aortic cross-clamping, monitoring of motor-evoked potentials (MEPs), cerebral, paraspinal and lower limbs oxygen saturations by near-infrared spectrometry as well as selective visceral perfusion via the coeliac, superior mesenteric and renal arteries. We advocate for individual branch reimplantation using a branched thoracoabdominal graft and when possible and we selectively reattach one or more pairs of the lower thoracic intercostal arteries and/or high lumbar arteries, even in absence of a significant reduction on the MEPs signal. The distal anastomosis is usually constructed above the aortic bifurcation and occasionally to each iliac separately using a bifurcated graft. Favorable early outcomes and a durable repair can be achieved at experienced high-volume centers, with standardized pre-operative selection and multidisciplinary team based intraoperative and postoperative management of these patients.

Quantification of visceral perfusion and impact of femoral cannulation: in vitro model of aortic dissection.

We aimed to simulate blood flow at an aortic dissection in an in vitro vascular model and assess the impact of the cannulation method on visceral perfusion. An aortic-dissection model with an acrylic aortic wall and silicone intimal flap was developed to study visceral perfusion under various cannulation conditions. The primary tear was placed in the proximal descending aorta and the re-entry site in the left common iliac artery. A cardiovascular pump was used to reproduce a normal pulsatile aortic flow and a steady cannulation flow. Axillary and axillary plus femoral cannulation were compared at flow rates of 3-7 l/min. Haemodynamics were analysed by using four-dimensional flow magnetic resonance imaging. Axillary cannulation (AC) was found to collapse the true lumen at the coeliac and superior mesentery arteries, while combined axillary and femoral cannulation did not change the size of the true lumen. Combined axillary and femoral cannulation resulted in a larger visceral flow than did AC alone. When axillary plus femoral cannulation was used, the visceral flow increased by 125% at 3 l/min, by 89% at 4 l/min, by 67% at 5 L/min, by 98% at 6 l/min and by 101% at 7 l/min, respectively, compared to those with the AC only. Our model was useful to understanding the haemodynamics in aortic dissection. In this specific condition, we confirmed that the intimal flap motion can partially block blood flow to the coeliac and superior mesenteric arteries and that additional femoral cannulation can increase visceral perfusion.

A retrievable, dual-chamber stent protects against warm ischemia of donor organs in a model of donation after circulatory death

BackgroundIschemic injury during the agonal period of donation after circulatory death donors remains a significant barrier to increasing abdominal transplants. A major obstacle has been the inability to improve visceral perfusion, while at the same time respecting the ethics of the organ donor. A retrievable dual-chamber stentgraft could potentially isolate the organ perfusion from systemic hypotension and hypoxia, without increasing cardiac work or committing the donor. MethodsRetrievable dumbbell-shaped stents were laser welded from nitinol wire and covered with polytetrafluoroethylene. Yorkshire pigs were assigned to either agonal control or dumbbell-shaped dual-chamber stentgraft. A central lumen maintained aortic flow, while an outer visceral chamber was perfused with oxygenated blood. A 1-hour agonal phase of hypoxia and hypotension was simulated. Stents were removed by simple sheath advancement. Cardiac monitoring, labs, and visceral flow were recorded followed by recovery of the animal to a goal of 48 hours. ResultsCardiac stress did not increase during stent deployment. Visceral pO2 and flow were dramatically improved in stented animal relative to control animals. Five of 7 control animals were killed after renal failure complications, whereas all stent animals survived. Histology confirmed increased ischemic changes among control kidneys compared to stented animals. ConclusionA dual-chamber stent improved outcomes after a simulated agonal phase. The stent did not increase cardiac work, thus respecting a key ethical consideration. The ability of a dual-chamber stent to prevent ischemia during organ recovery may become a powerful tool to address the critical donor organ shortage.

Effect of Anastomosis Angles on Retrograde Perfusion and Hemodynamics of Hybrid Treatment for Thoracoabdominal Aortic Aneurysm

Hemodynamic effects on the retrograde visceral reconstruction (RVR) for thoracoabdominal aortic aneurysms treatment by anastomotic angle remains unclear. This study aims to qualitatively and quantitatively investigate the effects of different anastomotic angles on hemodynamics and patency. Three RVR models with 45°, 60° and 90° anastomotic angles were reconstructed respectively by manipulating apostoperative patient-specific model. The manipulated models of the RVRs were numerically simulated and analyzed in terms of hemodynamics including theinstant and cumulative patency, flow pattern and indicators based on wall shear stress (WSS). Although a smaller anastomotic angle may decrease the patency rate of common iliac arteries, it can improve the visceral perfusion during a cardiac cycle. More importantly, RVR with the smallest anastomotic angle experienced a minimal low time-averaged wall shear stress, high oscillatory shear index and relative residence time in the anastomosis region, whereas the largest anastomotic angle can introduce more unfavorable WSS in the graft trunk. Furthermore, a spiral flow pattern was observed in the proximal graft trunk of all three models, where no high-risk shear distribution was detected in this region. A smaller anastomotic angle may have more benefits of hemodynamic environment in RVR, especially the WSS distribution and flow pattern in the graft trunk. We may also suggest that additional stents or an extended cuff for the graft can be used to induce spiral flow intentionally, which can further improve local hemodynamic environment and long-term prognosis.

WHOLE BODY PERFUSION STRATEGY FOR AORTIC ARCH REPAIR UNDER NORMOTERMIA AND BEATING HEART TECHNIQUE IN PEDIATRIC PATIENTS. THREE CLINICAL CASES

Introduction The incidence of aortic arch pathology in older children is rare. Most often this occurs as a result of a previous aortic arch operation and less often it could be detected primarily. Previously, we successfully used normothermic perfusion during neonatal aortic arch repair. In this paper we evaluate the effectiveness of the method of selective whole body perfusion with coronary perfusion on the beating heart during aortic arch reconstruction in older children. Methods Between October 2019 and February 2021, 3 children underwent aortic arch surgery at our institution using the defined protocol. During the cardiopulmonary bypass (CPB), antegrade cerebral perfusion (ACP), antegrade coronary perfusion on beating heart and distal retrograde femoral aortic perfusion at a constant blood temperature 36 C were used. During the surgery, cerebral and visceral perfusion were monitored using near-infrared spectroscopy (NIRS) and transcranial dopplerography, electrocardiography and arterial blood gases. The data was collected prospectively. Results Patient one. Male, 6 years old, 27 kg. Elective admission. Diagnosis: Aortic arch hypoplasia. Surgery: Aortic arch reconstruction. CPB: Normothermic. Selective ACP, antegrade coronary perfusion on beating heart and distal retrograde femorall aortic perfusion. Flow 2,5 l/min. CPB time – 78 min, ACP – 44 min. BCA cannula – 14 fr, coronary cannula – 4fr, femoral artery cannula – 10 fr. Ultrafiltration during CPB. Mechanical ventilation - 18 hours post/op. Blood lactate 6 hours post/op – 1,8 mmol/l. ICU admission – 24 hours. Hospital discharge 12 days. Patient two, 17 y.o., 38 kg. Elective admission. Diagnosis: Aortic arch hypoplasia. The history of coarctation of the aorta surgery. Surgery: Aortic arch reconstruction. CPB: Normothermic. Selective ACP, antegrade coronary perfusion on beating heart and distal retrograde femorall aortic perfusion. Flow 2,5 l/min. CPB time – 136 min, ACP time – 54 min. BCA cannula – 14 fr, coronary cannula – 4fr, femoral artery cannula – 15 fr. Ultrafiltration during CPB. Mechanical ventilation – 4 hours post/op. Blood lactate 6 hours post/op – 2,6 mmol/l. ICU admission – 16 hours. Hospital discharge 17 days. Patient three. Female, 4 years old, 15 kg. Admitted urgently. Diagnosis: Critical aortic arch stenosis. Brachiocephalic artery (BCA) and left common carotid artery (LCCA) stenosis. The history of coarctation of the aorta surgery. Low ejection fraction. Surgery: Aortic arch, BCA and LCCA repair. CPB: Normothermic. Selective ACP, antegrade coronary perfusion on beating heart and distal retrograde femorall aortic perfusion. Flow 3 l/min. CPB time – 107 min, ACP – 68 min. BCA cannula – 12 fr, coronary cannula – 4fr, femoral artery cannula – 12 fr. Ultrafiltration during CPB. Mechanical ventilation - 44 hours post/op. Blood lactate 6 hours post/op – 1,6 mmol/l. ICU admission – 5 days. Hospital discharge 26 days. During surgery, laboratory and instrumental parameters were within reference values. Patients had no neurological deficiency during hospital stage. Discussion These clinical cases show that the whole-body perfusion with coronary perfusion on beating heart provide safe conditions during aortic arch surgery in children using normothermia. Using this protocol, we were able to eliminate risk factors: circulatory arrest, hypothermia, cardioplegia, extended

Endovascular management of type B aortic dissection with coverage of proximal entry tear with a TEVAR and bare metal stenting of renal and mesenteric vessels to maintain visceral perfusion

Endovascular management of type B aortic dissection with coverage of proximal entry tear with a TEVAR and bare metal stenting of renal and mesenteric vessels to maintain visceral perfusion

Single-stage total aortic replacement in patients with mega-aortic syndrome

Staged total aortic replacement (TAR) is standard for patients with mega-aortic syndrome (MAS) and severe comorbidities, but a single-stage approach may be better for younger and fit patients. This report described the mid-term results of this approach. We conducted a retrospective medical chart review of all MAS patients in our center between May 2016 and December 2020 to analyze outcomes of single-stage TAR. Primary endpoints were mortality and major adverse postoperative events; secondary endpoints included aortic re-intervention, all complications, and survival. Of 47 MAS patients, 13 (27.7%) received single-stage TAR from valve to bifurcation through thoracophrenolumbotomy using circulatory arrest, antegrade cerebral and visceral perfusion. Mean age was 40.1±6.5 years. In-hospital mortality was 15.4%; two patients died on postoperative day (POD) 14 due to fatal stroke and POD 85 due to prosthesis infection. Mean intensive care stay was 7 (15) day, mean hospital stay was 27.5±16.2 day. Stroke occurred in two patients with "shaggy" aortas (one fatal, one transient); paraplegia in one; temporary acute renal failure in two (15.4%), and respiratory failure in 4 (30.8%). There was no aortic re-intervention or further mortality during follow-up. Total aortic replacement from valve to bifurcation is a safe approach for younger and fit patients with MAS and provides acceptable midterm outcomes in an experienced center. Thoracoabdominal incision at fourth intercostal space with retroperitoneal approach of abdominal aorta provides satisfactory exposure for the thoracic aorta and TAA and minimizes surgical trauma in comparison with a combination of two surgical incision.