Predictive value of a novel digital risk calculator to determine early patient outcomes after major surgery: a proof-of-concept pilot study.

BACKGROUND: A structured risk assessment of patients with validated and evidence-based tools can help to identify modifiable factors before major surgeries. The Protego Maxima trial investigated the value of a new digitized risk assessment tool that combines tools which can be easily used and implemented in the clinical workflow by doctors and qualified medical staff. The hypothesis was that the structured assessment and risk-grouping is predictive of short-term surgical quality reflected by complications and overall survival. METHODS: The Protego Maxima Trial was a prospective cohort analysis of patients undergoing major surgery (visceral, thoracic, urology, vascular and gynecologic surgeries) as key inclusion criterion and the absence of an acute or acute on chronically decompensated pulmo-cardiovascular decompensation. Patients were risk-scored with the software (The Prehab App) that includes a battery of evidence-based risk assessment tools that allow a structured risk assessment. The data were grouped to predefined high and low risk groups and aggregate and individual scores. The primary outcome was to validate the predictive value of the RAI score and the TUG for overall survival in the high and low risk groups. Secondary outcomes were surgical outcomes at 90-days after surgery (overall survival, Clavien-Dindo (CD) 1-5 (all complications), and CD 3-5 (major complications)). The study was carried out in accordance with the DIN ISO 14,155, and the medical device regulation (MDR) at Frankfurt University Hospital between March 2022 and January 2023. RESULTS: In total 267 patients were included in the intention to treat analysis. The mean age was 62.1 ± 12.4 years. Patients with a RAI score > 25 and/or a timed up and go (TUG) > 8 s had a higher risk for mortality at 90 days after surgery. The low-risk group predicted beneficial outcome and the high-risk group predicted adverse outcome in the ROC analysis (Area Under the Curve Receiver Operator Characteristics: AUROC > 0.800; p = 0.01). Risk groups (high vs. low) showed significant differences for 90-day survival (99.4% vs. 95.5%; p = 0.04) and major complications (16.4% vs. 32.4%; p < 0.001). CONCLUSION: The proof-of-concept trial showed that a risk assessment with 'The Prehab App' may be viable to estimate the preoperative risk for mortality and major complications before major surgeries. The overall performance in this initial set of data indicated a certain reliability of the scoring and risk grouping, especially of the RAI score and the TUG. A larger data set will be required to proof the generalizability of the risk scoring to every subgroup and may be fostered by artificial intelligence approaches. TRIAL REGISTRATION: Ethics number: 2021-483-MDR/MPDG-zuständig monocentric; The Federal Institute for Pharmaceuticals and Medical Devices/BfArM, reference number: 94.1.04-5660-13655; Eudamed: CIV-21-07-0307311; German Clinical Trial Registry: DRKS 00026985.

Correlation of four-dimensional ultrasound strain analysis with computed tomography angiography wall stress simulations in abdominal aortic aneurysms.

Objective: Biomechanical modeling of infrarenal aortic aneurysms seeks to predict ruptures in advance, thereby reducing aneurysm-related deaths. As individual methods focusing on strain and stress analysis lack adequate discretization power, this study aims to explore multifactorial characterization for progressive aneurysmal degeneration. The study's objective is to compare stress- and strain-related parameters in infrarenal aortic aneurysms. Methods: Twenty-two patients with abdominal aortic aneurysms (AAAs) (mean maximum diameter, 53.2 ± 7.2 mm) were included in the exploratory study, examined by computed tomography angiography (CTA) and three-dimensional real-time speckle tracking ultrasound (4D-US). The conformity of aneurysm anatomy in 4D-US and CTA was determined with the mean point-to-point distance (MPPD). CTA was employed for each AAA to characterize stress-related indices using the semi-automated A4-clinics RE software. Five segmentations from one 4D-US examination were fused into one averaged model for strain analysis using MATLAB and the Abaqus solver. Results: The mean MPPD between the adjacent points of the 4D-US and CTA-derived geometry was 1.8 ± 0.4 mm. The interclass correlation coefficients for all raters and all measurements for the maximum AAA diameter in 2D, 4D ultrasound, and CTA indicate moderate to good reliability (interclass correlation coefficient1 0.69 with 95% confidence interval [CI], 0.49-0.84; P < .001). The peak wall stress (PWS) correlates fairly with the maximum AAA diameter in 2D-US (r = 0.54; P < .01) and 4D-US (r = 0.53; P < .05) and moderately strongly with the maximum exterior AAA diameter (r = 0.63; P < .01). The peak wall rupture risk index shows a strong correlation with the PWS (ρ > 0.9; P < .001) and is influenced by anatomical parameters with equal strength. Isolated observation of the intraluminal thrombus does not provide significant information in the determination of PWS. The maximum AAA diameter in 2D-US shows a fair negative correlation with the mean circumferential, longitudinal and in-plane shear strain (ρ = -0.46; r = -0.45; ρ = -0.47; P < .05 for all). The circumferential strain ratio as an indicator of wall motion heterogeneity increases with the aneurysm diameter (r = 0.47; P < .05). The direct comparison of wall strain and wall stress indices shows no quantitative correlation. Conclusions: The strain and stress analyses provide independent biomechanical information of AAAs. At the current stage of development, the two methods are considered complementary and may optimize a more patient-specific rupture risk prediction in the future.

Effect of using smaller blood volume tubes and closed blood collection devices on total blood loss in patients undergoing major cardiac and vascular surgery.

BACKGROUND: Diagnostic laboratory tests are an integral part of managing hospitalized patients. In particular, patients in the intensive care units (ICUs) can experience a concerning amount of blood loss due to diagnostic testing, which can increase the risk developing iatrogenic anemia. Several interventions exist to curtail avoidable blood loss, for example computerized decision support, smaller phlebotomy tubes, and other blood conservation devices. Nevertheless, use of these interventions is not standardized. Therefore, the objective of our study was to quantify the daily phlebotomy volume taken from patients who had undergone major cardiac or vascular surgery. METHODS: We estimated the number of blood analyses and volumes of drawn blood of 400 consecutive patients (≥ 18 yr) undergoing major cardiac or vascular surgery. The amount of blood saved using small-volume tubes and in combination with blood conservation device rather than standard-volume tubes was estimated for serum chemistry (serum), ethylenediaminetetraacetic acid (EDTA) tubes, sodium citrate coagulation (SCC) tubes, and arterial blood gas (ABG) analysis. RESULTS: The mean total blood loss due to phlebotomy drawing using standard-volume tubes during hospitalization was 167.9 mL (95% confidence interval [CI], 158.0 to 177.8), 255.6 mL (95% CI, 226.5 to 284.6), and 695.3 mL (95% CI, 544.1 to 846.4) for patients undergoing cardiac surgery with a hospital length of stay (LOS) of 0-10, 11-20, and ≥ 21 days, respectively. The mean total blood loss due to phlebotomy during hospitalization was 80.5 mL (95% CI, 70.5 to 90.6), 225.0 mL (95% CI, 135.1 to 314.8 mL) and 470.3 mL (95% CI, 333.5 to 607.1) for vascular surgery patients with LOS 0-10, 11-20, and ≥ 21 days, respectively. Patients with at least a two-day stay at the ICU had a mean blood loss of 146.6 mL (95% CI, 134.6 to 158.6 mL) and those with ≥ 11 days incurred a loss of 1,428 mL (95% CI, 1,117.8 to 1,739.2). The use of closed blood collection device and small-volume tubes (serum, EDTA, SCC, and ABG) reduced blood loss by 82.8 mL for patients with an ICU stay of 2 days and up to 824.0 mL for patients with a ICU stay of ≥ 11 days. CONCLUSION: Diagnostic laboratory tests are associated with significant patient blood loss, but are a modifiable risk factor. The use of small-volume tubes and closed blood collection devices decreases the volume of patient blood drawn for analysis and prevents blood waste.

RéSUMé: CONTEXTE: Les tests diagnostiques de laboratoire font partie intégrante de la prise en charge des personnes hospitalisées. Plus spécifiquement, la patientèle des unités de soins intensifs (USI) peut perdre une quantité inquiétante de sang en raison des tests de diagnostic, ce qui peut augmenter le risque d'anémie iatrogène. Plusieurs interventions existent pour réduire les pertes de sang évitables, par exemple une aide à la décision informatisée, des tubes de phlébotomie plus petits et d'autres dispositifs de conservation du sang. Néanmoins, le recours à ces interventions n'est pas normalisé. Par conséquent, l'objectif de notre étude était de quantifier le volume quotidien de phlébotomie prélevée chez des patient·es ayant bénéficié d'une chirurgie cardiaque ou vasculaire majeure. MéTHODE: Nous avons estimé le nombre d'analyses sanguines et les volumes de sang prélevés de 400 personnes consécutives (≥ 18 ans) bénéficiant d'une chirurgie cardiaque ou vasculaire majeure. La quantité de sang économisée à l'aide de tubes de petit volume et en combinaison avec un dispositif de conservation du sang plutôt que des tubes de volume standard a été estimée pour la chimie sérique (sérum), les tubes d'acide éthylène-diamine-tétra-acétique (EDTA), les tubes de coagulation au citrate de sodium (CCS) et l'analyse des gaz du sang artériel (GSA). RéSULTATS: La perte sanguine totale moyenne due au prélèvement de phlébotomie à l'aide de tubes de volume standard pendant l'hospitalisation était de 167,9 mL (intervalle de confiance [IC] à 95 %, 158,0 à 177,8), 255,6 mL (IC 95 %, 226,5 à 284,6) et 695,3 mL (IC 95 %, 544,1 à 846,4) chez les patient·es bénéficiant d'une chirurgie cardiaque avec une durée de séjour à l'hôpital de 0 à 10, 11 à 20, et ≥ 21 jours, respectivement. La perte sanguine totale moyenne due à la phlébotomie pendant l'hospitalisation était de 80,5 mL (IC 95 %, 70,5 à 90,6), 225,0 mL (IC 95 %, 135,1 à 314,8 mL) et 470,3 mL (IC 95 %, 333,5 à 607,1) chez les patient·es ayant bénéficié d'une chirurgie vasculaire avec des durées de séjour de 0-10, 11-20 et ≥ 21 jours, respectivement. Les patient·es ayant séjourné au moins deux jours à l'USI ont eu une perte de sang moyenne de 146,6 mL (IC 95 %, 134,6 à 158,6 mL) et celles et ceux ayant séjourné ≥ 11 jours ont subi une perte de 1428 mL (IC 95 %, 1117,8 à 1739,2). L'utilisation d'un dispositif de prélèvement sanguin fermé et de tubes de petit volume (sérum, EDTA, SCC et gsa) a réduit la perte de sang de 82,8 mL pour les patient·es ayant séjourné à l'USI 2 jours et jusqu'à 824,0 mL pour les patient·es ayant séjourné en USI ≥ 11 jours. CONCLUSION: Les tests de laboratoire diagnostiques sont associés à une perte de sang importante chez les patient·es, mais constituent un facteur de risque modifiable. L'utilisation de tubes de petit volume et de dispositifs fermés de prélèvement sanguin diminue le volume de sang prélevé pour analyse et prévient le gaspillage de sang.

[Epidemiology and diagnostics of mesenteric ischemia]. / Epidemiologie und Diagnostik der mesenterialen Ischämie.

BACKGROUND: Mesenteric ischemia is a life-threatening condition with a complex etiology and diagnostics. OBJECTIVE: Etiology, incidence, symptoms, and diagnostics of acute and chronic mesenteric ischemia. MATERIAL AND METHODS: Literature search via PubMed with a focus on studies on the epidemiology and diagnostics of mesenteric ischemia and analysis of existing international guidelines. RESULTS: The incidence of acute mesenteric ischemia is given as 0.63-12.9 per 100,000 people per year. There are no sufficiently reliable figures for chronic mesenteric ischemia, but an incidence of up to 3 per 100,000 inhabitants per year is generally assumed. The three-phase computed tomography has the highest diagnostic specificity and sensitivity. CONCLUSION: In the presence of risk factors acute and chronic mesenteric ischemia should be considered as differential diagnoses in the presence of abdominal pain using three-phase computed tomography.

Influence of Patient Anatomy on Intraoperative Radiation Exposure and Operation Time during Standard EVAR.

Endovascular aortic repair (EVAR) is the primary treatment for abdominal aortic aneurysms (AAAs). To optimise patient safety during the standard EVAR procedure, we aimed to investigate the influence of patient anatomy on intraoperative radiation exposure and surgical time. This retrospective study comprised 90 patients (mean age 73.4 ± 8.2 years; 92.2% male) with an infrarenal aortic aneurysm who underwent a standard EVAR procedure. The relationships between dose area product, operating time, and anatomical conditions were investigated in preoperative computed tomography angiography using open-source software. Logistic regression analysis indicated that only body mass index (BMI) had predictive value for radiation exposure. The accuracy of the model was 98.67%, with an area under the curve of 0.72. The duration of surgery was significantly correlated with an increased BMI (odds ratio (OR) = 1.183; p < 0.05), the tortuosity of AAAs (OR = 1.124; p < 0.05), and the left common iliac artery (OR = 1.028; p < 0.05). Thus, BMI impacts the prediction of intraoperative radiation exposure more significantly than the anatomical characteristics of the infrarenal aorta and iliac arteries, and the duration of surgery significantly correlates with both BMI and the tortuosity of the infrarenal aorta and iliac arteries.

Using averaged models from 4D ultrasound strain imaging allows to significantly differentiate local wall strains in calcified regions of abdominal aortic aneurysms.

Abdominal aortic aneurysms are a degenerative disease of the aorta associated with high mortality. To date, in vivo information to characterize the individual elastic properties of the aneurysm wall in terms of rupture risk is lacking. We have used time-resolved 3D ultrasound strain imaging to calculate spatially resolved in-plane strain distributions characterized by mean and local maximum strains, as well as indices of local variations in strains. Likewise, we here present a method to generate averaged models from multiple segmentations. Strains were then calculated for single segmentations and averaged models. After registration with aneurysm geometries based on CT-A imaging, local strains were divided into two groups with and without calcifications and compared. Geometry comparison from both imaging modalities showed good agreement with a root mean squared error of 1.22 ± 0.15 mm and Hausdorff Distance of 5.45 ± 1.56 mm (mean ± sd, respectively). Using averaged models, circumferential strains in areas with calcifications were 23.2 ± 11.7% (mean ± sd) smaller and significantly distinguishable at the 5% level from areas without calcifications. For single segmentations, this was possible only in 50% of cases. The areas without calcifications showed greater heterogeneity, larger maximum strains, and smaller strain ratios when computed by use of the averaged models. Using these averaged models, reliable conclusions can be made about the local elastic properties of individual aneurysm (and long-term observations of their change), rather than just group comparisons. This is an important prerequisite for clinical application and provides qualitatively new information about the change of an abdominal aortic aneurysm in the course of disease progression compared to the diameter criterion.

Sex difference in early mortality after abdominal aortic aneurysm repair.

OBJECTIVE: Although female patients have a lower prevalence of abdominal aortic aneurysm (AAA), they seem to have a worse treatment outcome compared with male patients. Both maximum aneurysm diameter and aortic size index (ASI) are important indicators of the risk of AAA rupture, among which ASI has been shown capable of equalizing sex-related anatomical differences. Our study aimed to investigate whether sex is an independent risk factor for early postoperative mortality and how the diameter or ASI affects the association between sex and mortality. METHODS: We performed a retrospective analysis of patients who enrolled in the AAA registry of the German Society of Vascular Surgery from 2013 to 2019. The patients were treated by either open surgical repair (OSR) or endovascular aneurysm repair (EVAR). The association between sex and 30-day mortality was investigated using logistic regression analysis. The interaction and mediating effects of maximum aneurysm diameter and ASI were investigated to verify their roles in the effect of sex on mortality. The relationships between the diameter (or ASI) and the risk of 30-day mortality in different sexes were demonstrated by the restricted cubic spline. RESULTS: Overall, 23,275 cases were included in our analysis, with 20,130 male (86.5%) and 3139 female (13.5%) patients. Female patients had a smaller maximum aneurysm diameter (OSR, 55.23 ± 10.29 mm vs 58.05 ± 11.28 mm [P < .001]; EVAR, 54.06 ± 9.08 mm vs 56.11 ± 9.38 mm [P < .001]), but a higher ASI (OSR, 3.16 ± 0.71 vs 2.92 ± 0.69 [P < .001]; EVAR, 3.05 ± 0.66 vs 2.80 ± 0.59 [P < .001]) compared with male patients. The 30-day mortality rate was higher for female patients in both OSR (6.6% vs 4.2%; P = .002) and EVAR groups (1.8% vs 0.8%; P < .001). Logistic regression confirmed a significantly higher risk of 30-day mortality for female patients compared with male patients (odds ratio, 1.55; 95% confidence interval, 1.21-1.99; P = .001). No interaction was found between sex and diameter or ASI, but there were mediating effects for diameter and ASI in the effect of sex on 30-day mortality. For female patients, the risk of 30-day mortality linearly increased with the increase of diameter (PNonlinear = .089) or ASI (PNonlinear = .888), whereas the risk for male patients was U-shaped (for diameter, PNonlinear < .001; for ASI, PNonlinear = .020). CONCLUSIONS: Sex is an independent risk factor for 30-day mortality after AAA repair. Both diameter and ASI are mediating factors for the effect of sex on 30-day mortality. The relationship between diameter or ASI and the risk of 30-day mortality is different for male and female patients.

Changes in Aortic Diameter and Wall Strain in Progressing Abdominal Aortic Aneurysms.

OBJECTIVES: The analysis of wall strain opens new perspectives in the prediction of abdominal aortic aneurysm (AAA) rupture. This study investigates the capability of four-dimensional ultrasound (4D US) to detect and characterize changes in wall strain in the same patients during follow-up observations. METHODS: Eighteen patients were examined by 64 4D US scans during a median follow-up period of 24.5 months. After performing the 4D US and manual aneurysm segmentation, kinematic analysis was performed using a customized interface and evaluation of the mean and peak circumferential strain, as well as spatial heterogeneity. RESULTS: All aneurysms showed a continuous diameter growth with a mean rate of 4% per year (P < .001). The mean circumferential strain (MCS) tends to increase from a median 0.89% by 10.49% per year in follow-up independent of the aneurysm diameter (P = .063). The subgroup analysis reveals a cohort with increasing MCS and decreasing spatial heterogeneity, as well as a cohort with nonincreasing MCS and increasing spatial heterogeneity (P < .05). CONCLUSIONS: The 4D US is able to register the strain changes in AAA follow-up. The MCS tends to increase during the observation time in the entire cohort, but the changes were independent of the maximum aneurysm diameter. The kinematic parameters allow the entire AAA cohort to differentiate into two subgroups and provide additional information about the pathologic behavior of the aneurysm wall.

Age and Oversizing Influence Iliac Dilatation after EVAR.

In the past two decades, endovascular aortic repair (EVAR) of abdominal aortic aneurysm (AAA) has become the first line treatment for infrarenal AAA repair in many countries. While short-term results are good, concerns have been raised about long-term durability. Changes in aortoiliac anatomy, especially at the landing zones, could play a role in EVAR failure over time. The current study aimed to determine certain morphological changes in the distal iliac landing zone after EVAR implantation, as well aspossible risk factors associated with iliac sealing failure. In a retrospective analysis of a tertiary single-centre registry, including patients treated with EVAR between January 2008 and July 2018, clinical follow-up data were assessed, and computer tomography (CT) imaging was evaluated regarding morphological changes in the iliac anatomy during follow-up. For clinical analysis all patients with a minimum follow-up of one year were included; for morphological analysis of iliac anatomy all patients with available CT follow-up of a minimum of one year and a minimum of two CT scans were included. Overall, 127 out of 241 treated patients (92.1% male) were included in the clinical follow-up. Complete CT imaging of 99 iliac arteries in 55 patients was available for morphological analysis. Median postoperative follow-up (FU) for these patients was 33 months (IQR 31; min−max: 12−124). Incidence of type 1b endoleak was 3% but iliac limb detachment from the vessel wall was seen in 18.2% of the target vessels. There was a significant difference in oversizing in iliac limbs with detachment (median 13.9%, IQR 23.1) vs. without detachment (median 23.1%, IQR 19.1) (p = 0.034). Iliac arteries at the landing zone showed a significant diameter increase independent of an endoleak presence (overall cohort median diameter increase at one year 23.1 mm; at two years 0 mm; at three years 4.9 mm). Iliac arteries with detachment (median 14.4%; IQR 23.9) showed a significantly higher diameter increase at the landing zone after four years compared to arteries without detachment (median 5.3%; IQR 9) (p = 0.042). Oversizing correlated positively with an iliac diameter increase at the landing zone over time (3 m: p= 0.001; one year: p < 0.001; two years: p < 0.001; three years: p = 0.006). Older patients showed a significantly lower diameter increase at the distal landing zone over time than younger patients in the first two years after EVAR (p < 0.001/r = −0.606 after two years). In the current study, iliac limb oversizing was associated with increased dilatation of the distal landing zone during a three-year follow-up, while iliac limb detachment was observed less often. An older age was inversely associated to the iliac diameter increase. Future studies should clarify the association between stent graft oversizing, age, and changes in the iliac anatomy in order to identify parameters that affect EVAR durability.

Systematic evaluation of imaging techniques and baseline characteristics in patients with suspected vasculitis.

Purpose: To assess the diagnostic value of different imaging modalities in distinguishing systemic vasculitis from other internal and immunological diseases. Methods: This retrospective study included 134 patients with suspected vasculitis who underwent ultrasound, magnetic resonance imaging (MRI), or 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) between 01/2010 and 01/2019, finally consisting of 70 individuals with vasculitis. The main study parameter was the confirmation of the diagnosis using one of the three different imaging modalities, with the adjudicated clinical and histopathological diagnosis as the gold standard. A secondary parameter was the morphological appearance of the vessel affected by vasculitis. Results: Patients with systemic vasculitis had myriad clinical manifestations with joint pain as the most common symptom. We found significant correlations between different imaging findings suggestive of vasculitis and the final adjudicated clinical diagnosis. In this context, on MRI, vessel wall thickening, edema, and diameter differed significantly between vasculitis and non-vasculitis groups (p < 0.05). Ultrasound revealed different findings that may serve as red flags in identifying patients with vasculitis, such as vascular occlusion or halo sign (p = 0.02 vs. non-vasculitis group). Interestingly, comparing maximal standardized uptake values from PET/CT examinations with vessel wall thickening or vessel diameter did not result in significant differences (p > 0.05). Conclusions: We observed significant correlations between different imaging findings suggestive of vasculitis on ultrasound or MRI and the final adjudicated diagnosis. While ultrasound and MRI were considered suitable imaging methods for detecting and discriminating typical vascular changes, 18F-FDG PET/CT requires careful timing and patient selection given its moderate diagnostic accuracy.

Real-world data of popliteal artery aneurysm treatment: Analysis of the POPART registry.

OBJECTIVE: Popliteal artery aneurysm (PAA) is a rare disease with a prevalence of 0.1% to 1%. Within previous years, endovascular repair (ER) of PAAs has been performed more frequently despite the lack of high-level evidence compared with open surgical repair (OSR). In 2014, the POPART registry was initiated to validate the current treatment options for PAA repair. METHODS: POPART is a multinational multicenter registry of the peri- and postoperative outcomes of ER and OSR for PAAs. Data sets were recorded using the online survey tool SurveyMonkey (available at: https://www.surveymonkey.com/). Regular monitoring and plausibility checks of the data sets are performed to ensure reliability. The aim of the present study was to report the findings from the POPART registry, which includes data from 41 centers. RESULTS: From June 2014 to August 2019, 794 cases had been recorded in the POPART registry. OSR had been performed in 662 patients and ER in 106 patients; 23 patients had been treated conservatively. Of the 106 patients in the primary ER group, 4 had required conversion to OSR. The ER patients were significantly older (ER, median, 71 years; OSR, median, 67 years; P < .05). No other significant differences were present in the demographic data, comorbidities, or aneurysm morphology between the two groups. Of the 662 patients in the OSR group, 50.3% were symptomatic compared with 29.2% of the 106 patients in the ER group (P < .05). Emergency treatment because of acute ischemia, critical ischemia, or rupture was necessary for 149 patients (22.5%) in the OSR group and 11 patients (10.3%) in the ER group. The most frequent postoperative complications were impaired wound healing (OSR, n = 47 [7.1%]; ER, n = 3 [2.8%]; P > .05) and major bleeding (OSR, n = 26 [3.9%]; ER, n = 3 [2.8%]; P > .05). The in-hospital length of stay was significantly longer for the OSR group than for the ER group (median, 10 days; range, 3-65 days; vs median, 7 days; range, 1-73 days). The overall patency for the OSR and ER groups after 12 and 24 months was 83.2% and 44.7% (P < .005) and 74.2% and 29.1% (P < .005), respectively. The outcomes with a prosthetic graft vs an autologous vein were significantly poorer in the OSR group (primary patency, 71.4% vs 88.1% at 12 months). CONCLUSIONS: To evaluate new treatment techniques such as ER for PAAs, real-world data are of essential importance. The present analysis of the first results for the POPART registry shows good perioperative results for endovascular treatment of PAA in asymptomatic patients with good outflow vessels. The perioperative complication rate is low and the postoperative hospital stay is shorter than after OSR. However, the patency rates after 12 and 24 months are low in the ER group compared to patients treated with open repair. More follow-up data is required for further interpretation; the completion of the data sets in the registry is ongoing.

Quiescent-Interval Slice Selective Magnetic Resonance Angiography for Abdominal Aortic Aneurysm Treatment Planning.

PURPOSE: Diagnostic imaging of Abdominal aortic aneurysm (AAA) almost exclusively employs CT angiography (CTA) involving X-ray exposure and contrast medium that may harm some patients. Quiescent-Interval Slice Selective MR (QISS-MR) depicts vascular anatomy without radiation or contrast medium. The diagnostic quality of QISS-MRA and CTA were compared in regard to length and diameter measurements in AAA patients. Suitability of QISS-MRA for AAA treatment planning was evaluated. MATERIALS AND METHODS: The details of 30 patients with AAA who received both a QISS-MR and CTA for a known infrarenal AAA were obtained retrospectively that was approved by the local research ethics board. Two observers analyzed each dataset in terms of image quality and determined lumen diameter and length of 15 vessel segments. RESULTS: Highly accurate agreement between the diagnostic scores from the two observers was achieved. There was no significant difference between CTA and QISS-MRA for all 15 measured vessels. Although information on calcification was lacking and intraluminal thrombus was visualized in only 25 patients out of 30 patients, a founded decision to carry out OR or EVAR was possible with both imaging modalities. CONCLUSION: QISS-MRA presents a radiation and contrast free method for preoperative diagnostic AAA imaging. While QISS-MRA does not deliver exact information regarding calcification and thrombus formation, it does accurately allow measurement of vessel diameter and length. Therefore, it is potentially useful for EVAR planning in selected patients with impaired renal function.

Intra- and Interobserver Variability of 4D Ultrasound Examination of the Infrarenal Aorta.

OBJECTIVES: The four-dimensional ultrasound (4D-US) enables imaging of the aortic segment and simultaneous determination of the wall expansion. The method shows a high spatial and temporal resolution, but its in vivo reliability is so far unknown for low-measure values. The present study determines the intraobserver repeatability and interobserver reproducibility of 4D-US in the atherosclerotic and non-atherosclerotic infrarenal aorta. METHODS: In all, 22 patients with non-aneurysmal aorta were examined by an experienced examiner and a medical student. After registration of 4D images, both the examiners marked the aortic wall manually before the commercially implemented speckle tracking algorithm was applied. The cyclic changes of the aortic diameter and circumferential strain were determined with the help of custom-made software. The reliability of 4D-US was tested by the intraclass correlation coefficient (ICC). RESULTS: The 4D-US measurements showed very good reliability for the maximum aortic diameter and the circumferential strain for all patients and for the non-atherosclerotic aortae (ICC >0.7), but low reliability for circumferential strain in calcified aortae (ICC = 0.29). The observer- and masking-related variances for both maximum diameter and circumferential strain were close to zero. CONCLUSIONS: Despite the low-measured values, the high spatial and temporal resolution of the 4D-US enables a reliable evaluation of cyclic diameter changes and circumferential strain in non-aneurysmal aortae independent from the observer experience but with some limitations for calcified aortae. The 4D-US opens up a new perspective with regard to noninvasive, in vivo assessment of kinematic properties of the vessel wall in the abdominal aorta.

Comparison of Abdominal Aortic Aneurysm Sac and Neck Wall Motion with 4D Ultrasound Imaging.

OBJECTIVE: The rupture of abdominal aortic aneurysms (AAAs) is associated with high mortality despite surgical developments. The determination of aneurysm diameter allows for follow up of aneurysm growth but fails in precisely predicting aneurysm rupture. In this study, time resolved three dimensional ultrasound (4D ultrasound) based wall motion indices (WMIs) are investigated to see if they are capable of distinguishing between uneven affected regions of the aneurysm wall. METHODS: In a prospective study, 56 patients with an AAA were examined using 4D ultrasound. Local longitudinal, circumferential, and shear strains were computed using custom methods. The deformation of the neck and sac of each aneurysm was characterised by statistical indices of the obtained distributions of local wall strains (WMIs): mean and peak strain, heterogeneity index, and local strain ratio. The locations of regions with highest local peak strain were determined. RESULTS: Compared with the aneurysm neck, the sac is characterised by low mean strain, but highly heterogeneous deformation, described by high local strain ratio and heterogeneity index. Differences were highly significant (p < .001) for all strain components. The regions with the highest circumferential peak strain were found more often in the posterior part of the aneurysm neck (p < .050) and sac (p < .001) regions, compared with other wall regions. No statistically significant correlation was found between the WMIs and maximum AAA diameter, except for longitudinal mean strain, which decreased with the increasing diameter (rho = -.42, p < .010). CONCLUSION: Characterisation of wall kinematics by 4D ultrasound based WMIs provides a new and independent criterion for the distinction of diseased tissue in the AAA sac and the less affected neck region. This is a promising step towards the establishment of new biomarkers to differentiate between the mechanical instability of the AAA and rupture risk.

[Therapy of Peripheral Artery Aneurysms]. / Therapie primärer Aneurysmen der Extremitätenarterien.

Peripheral arterial aneurysms are rare vascular pathologies characterised by focal dilatation of at least 1.5-fold relative to the diameter of the native vessel. Primary arterial aneurysms can affect any segment of the arterial trunk. Diagnostic tests include duplex sonography, CT and MR angiography, and digital subtraction angiography. It is essential that the influx and efflux to the aneurysm should be mapped as precisely as possible. The most common type of peripheral arterial aneurysms are popliteal artery aneurysms, which frequently occur with aorta aneurysms. Peripheral arterial aneurysms are more common in patients with connective tissue disease or autoimmune disease (Ehlers-Danlos syndrome, Marfan syndrome, Behçet's disease). The current gold standard for therapy is surgery, although endovascular therapies have also been described. As the condition is rare, there is insufficient evidence to compare these approaches. Results from several register studies and single centre studies in patients with popliteal aneurysms indicate that endovascular therapy can give similar outcomes to open therapy if patients are carefully selected. Nevertheless, open surgery remains the gold standard. Therapy of aneurysms of the extremities must consider individual treatment criteria, such as the morphology of the aneurysm, its anatomical localisation - particularly with respect to mobilise segments, vascular efflux and the patient's general condition.

[Management of Visceral Artery Aneurysms with Preservation of Organ Perfusion: More Than Twenty Years Experience]. / Management von Viszeralarterienaneurysmen unter besonderer Berücksichtigung der Organperfusion ­ Erfahrungen über mehr als 20 Jahre.

BACKGROUND: Visceral artery aneurysms (VAA) are rare and often incidental findings. Indications for treatment are symptomatic patients, pseudoaneurysms and a true aneurysm of diameter of ≥ 2.5 cm for mesenteric arteries and ≥ 3 cm for renal artery aneurysms. Pregnancy and liver transplantation play an important role in aneurysm rupture. Technical success after open or endovascular procedure and maintenance of organ perfusion are crucial. The aim of this review is to evaluate our data and experience of more than 20 years and to develop a strategy to deal with visceral artery aneurysm in elective and emergency cases. PATIENTS: Between 1995 and 2018, 179 patients (84 males, 95 females, median age 62 [18 - 87] years) were diagnosed with VAA at the Regensburg University Hospital. The site of aneurysm was the splenic artery in 113 (63%) patients (pts), hepatic and renal arteries in 22 and 21 pts (12% each), and gastropancreaticoduodenal artery in 14 (8%) and superior/inferior mesenteric artery in 9 (5%) cases. Surveillance without intervention occurred in 110 (62%) pts, and 34 (19%) pts underwent open and 35 (19%) endovascular repair. In all patients, preoperative imaging was performed, preferably by computed tomography angiography (CTA). RESULTS: A total of 69 patients underwent open or endovascular repair. 51 (74%) pts were treated electively, 18 (26%) pts presented urgently with acute bleeding. 16 emergency pts received endovascular treatment, and in 2 pts open surgery was performed. After emergency treatment, two pts exhibited segmental liver malperfusion without consequences. In one case, segmental bowel resection was necessary. 32/51 (63%) patients were treated electively by open surgery, 19/51 (37%) by endovascular procedures. There were no liver or bowel infarctions. Four splenectomies and one unilateral nephrectomy were necessary in patients with splenic or renal artery aneurysms. Moreover, three partial renal infarctions were noticed postoperatively (overall 8/21 [38%]). After endovascular repair of splenic or renal artery aneurysms, two cases of splenic and three cases of renal segmental infarction were observed. Splenectomy had to be performed twice (overall 7/14 [50%]). Organ perfusion was monitored by CTA, and preferentially by contrast enhanced ultrasound. CONCLUSION: The endovascular approach is the preferred option in an emergency to control bleeding in pseudoaneurysms. Patients for elective splenic or renal artery aneurysm repair have to be evaluated very carefully to achieve technical success with occlusion of the aneurysm and excellent organ perfusion. Imaging techniques such as ultrasound, especially CEUS, are strongly recommended in postoperative follow-up. Partial or complete splenic infarction leads to vaccination.

Multispecies blow fly myiasis combined with hypothermia in a man assumed to be dead.

We describe the case of a man who was found with severe hypothermia and advanced myiasis involving five species of blow flies, which eventually led to a transtibial amputation of the man's right leg. A case of such a heavy and species-rich infestation with fly larvae in an urban environment is extraordinary and has, to our knowledge, never been described so far. Best practice in cases such as this one demands accurate species identification not only to ensure appropriate treatment and pest management but also, from a forensic point of view, to explore the possibility of third-party responsibility. The cooperation between physicians and forensic entomologists is highlighted.

A finite element updating approach for identification of the anisotropic hyperelastic properties of normal and diseased aortic walls from 4D ultrasound strain imaging.

Computational analysis of the biomechanics of the vascular system aims at a better understanding of its physiology and pathophysiology and eventually at diagnostic clinical use. Because of great inter-individual variations, such computational models have to be patient-specific with regard to geometry, material properties and applied loads and boundary conditions. Full-field measurements of heterogeneous displacement or strain fields can be used to improve the reliability of parameter identification based on a reduced number of observed load cases as is usually given in an in vivo setting. Time resolved 3D ultrasound combined with speckle tracking (4D US) is an imaging technique that provides full field information of heterogeneous aortic wall strain distributions in vivo. In a numerical verification experiment, we have shown the feasibility of identifying nonlinear and orthotropic constitutive behaviour based on the observation of just two load cases, even though the load free geometry is unknown, if heterogeneous strain fields are available. Only clinically available 4D US measurements of wall motion and diastolic and systolic blood pressure are required as input for the inverse FE updating approach. Application of the developed inverse approach to 4D US data sets of three aortic wall segments from volunteers of different age and pathology resulted in the reproducible identification of three distinct and (patho-) physiologically reasonable constitutive behaviours. The use of patient-individual material properties in biomechanical modelling of AAAs is a step towards more personalized rupture risk assessment.