[Establishment of a new research concept at a university location]. / Die Etablierung eines neuen Forschungskonzepts an einem universitären Standort.

Apart from daily clinical work and patient care, research and student teaching are essential assignments of a university hospital. The implementation of a completely new research laboratory at the Department of Vascular Surgery at the Medical University of Innsbruck led to the creation of a novel infrastructure for the design and set-up of a newly founded research focus. The cooperation with national as well as international research collaborators was essential for this process. The construction of a research network is not only important for the design and conception of a new research laboratory but also for the development of new study protocols and exchange and discussion of results. After the successful implementation of Experimental Vascular Surgery in Innsbruck, the realization of basic research projects as well as translational research projects is possible at this university location. Moreover, simulation training is an emerging field of research that aims to add more realistic surgical skills to residency programs, attract future residents and teach more complex novel techniques.

Risk factors for major amputation after arterial vascular trauma of the lower extremity.

BACKGROUND & OBJECTIVE: Arterial vascular trauma bears a great risk of poor functional outcome or limb loss. The aim of this study was to analyze amputation rates of patients after vascular trauma and to perform a predictor analysis for the risk of major amputation. METHODS: In a single-center retrospective analysis of 119 extremities treated for arterial vascular injury between 1990 and 2018 amputation rates and factors associated with limb loss were assessed. All patients were treated for traumatic vascular injuries; iatrogenic injuries were not included in the study. RESULTS: During the study period, a total of 119 legs in 118 patients were treated after arterial vascular trauma. The in-hospital major amputation rate was 16.8% and the mortality rate was 2.5%. In the predictors analysis, vascular re-operation (amputation rate 53.8% vs 12%, odds ratio = 8.56), a Rutherford category ⩾IIb (25.4% vs 4.2%, odds ratio = 6.43), work-related or traffic accidents (28.2% vs 0%, odds ratio = 4.86), concomitant soft tissue or bone injuries (26.7% vs 7.3%, odds ratio = 4.64), polytrauma (33.3% vs 12%, odds ratio = 3.68), and blunt trauma (18.9% vs 0% for penetrating trauma, odds ratio = 1.64) were found to be associated with amputation. CONCLUSIONS: Lower extremity arterial vascular trauma was associated with a significant major amputation rate. Several predictors for limb loss were identified, which could aid in identifying patients at risk and adapting their treatment.

Predictors for the need for fasciotomy after arterial vascular trauma of the lower extremity.

INTRODUCTION: Compartment syndrome of the lower extremity following arterial vascular trauma can cause irreversible damage to muscle as well as nerve tissue leading to long-term functional impairment of the extremity or worse limb loss. Prompt diagnosis and treatment of compartment syndrome is mandatory to preserve muscle tissue and prevent limb loss. The aim of the study was to analyze the fasciotomy rate of our patient cohort and to perform a predictors analysis for the need of fasciotomy. MATERIAL AND METHODS: In a retrospective study all patients treated for arterial vascular trauma since 1990 were identified. Demographics, clinical data and outcome were analysed. After separation in a fasciotomy and non-fasciotomy group, a Bayes Network was used to arrive at a predictor ranking for the need of fasciotomy via a gain ratio feature evaluation. RESULTS: In the period of 28 years, 88 (73.9%) of a total of 119 patients, predominantly male (80.7%) and aged under 40 years (37.5 ± 17.5), required fasciotomy after arterial vascular trauma. Patients of the fasciotomy group presented at higher Rutherford categories (grade III 34.1% vs. 9.7%, p = 0.005), varied in terms of the type of arterial vascular injury (dissection 25% vs. 61.3%, p <0.001, occlusion 15.9% vs. 0%, p = 0.011) and showed prolonged hospitalization (35.17 ± 29.3 vs. 21.48±25.4, p = 0.002). Ischaemia duration exceeding 2.5 h followed by the Rutherford grade IIa and greater, the site (popliteal artery segment 3), type (transection and occlusion), and mechanism of vascular trauma (work related accident over traffic and sports accidents), as well as the male gender presented as strong predictors for fasciotomy. CONCLUSIONS: Arterial vascular trauma requiring fasciotomy for compartment syndrome accounted for 73.9% of all cases. Immediate diagnosis and treatment is mandatory to prevent long-term functional impairment or limb loss. The above mentioned predictors should help identifying patients at risk for developing a compartment syndrome to provide best possible treatment.

Cardiac output and cerebral blood flow during carotid surgery in regional versus general anesthesia: A prospective randomized controlled study.

OBJECTIVE: Carotid endarterectomy (CEA) is a preventive procedure aimed at decreasing the subsequent risk of fatal or disabling stroke in patients with significant carotid stenosis. It is well-known that carotid surgery under ultrasound-guided regional anesthesia (US-RA) causes a significant increase in blood pressure, heart rate and stress hormone levels owing to increased sympathetic activity. However, little is known about the effects on cardiac output (CO), cardiac index (CI), and cerebral blood flow (CBF) under US-RA as compared with general anesthesia (GA). METHODS: Patients scheduled for CEA were randomized prospectively to receive US-RA (n = 37) or GA (n = 41). The primary end point was the change in CI after induction of anesthesia and the change from baseline over time at four different times during the entire procedure in the respective randomized US-RA and GA groups. In addition to systolic blood pressure and heart rate, we also recorded peak systolic velocity, end-diastolic velocity, and minimum diastolic velocity as seen from transcranial Doppler ultrasound examination, as well as regional cerebral oxygenation (rSO2) as seen from near-infrared refracted spectroscopy to evaluate cerebral blood flow. RESULTS: In the US-RA group, the CI increased after induction of anesthesia (3.7 ± 0.8 L/min/m2) and remained constant until the end of the procedure. In the GA group CI was significantly lower (2.4 ± 0.6 L/min/m2; P < .001). After induction of anesthesia, the rSO2 remained constant in the GA group on both the ipsilateral (63 ± 9 rSO2) and the contralateral (65 ± 7 rSO2) sides; in contrast, it significantly increased in the US-RA group (ipsilateral 72 ± 8 rSO2; P < .001; contralateral 72 ± 6 rSO2; P < .001). The transcranial Doppler ultrasound parameters (peak systolic velocity, end-diastolic velocity, and minimum diastolic velocity) did not differ between the US-RA and the GA group. The clinical outcome was similarly favorable for both groups. CONCLUSIONS: CI was maintained near baseline values throughout the procedure during US-RA, whereas a significant decrease in CI values was observed during CEA under GA. Near-infrared refracted spectroscopy values, reflecting blood flow in small vessels, were higher in US-RA patients than in those with GA. These differences did not influence clinical outcome.

Management and prognosis of acute extracranial internal carotid artery occlusion.

Acute occlusion of the internal carotid artery is the underlying etiology in 4 to 15% of all ischemic strokes. The clinical presentation varies considerably ranging from asymptomatic occlusion to severe ischemic strokes. Substantial differences in the acute management of acute symptomatic internal carotid artery occlusions (ICAO) exists between centers. Thusly, we comprised a narrative review of the natural course of acute ICAO and of available treatment options [i.v. thrombolysis, endovascular thrombectomy and stenting, bypass between the superficial temporal and the middle cerebral arteries (MCA) and carotid endarterectomy (CEA)]. We found that very few randomized treatment trials have been performed in patients acute symptomatic ICAO. Most evidence stems from case series and observational studies. Especially in older studies the intracranial vessel status has rarely been considered. After revision of these studies we concluded that the mainstay of the acute management of acute symptomatic ICAO is i.v. thrombolysis when applied within the label and in combination with mechanical thrombectomy in case of intracranial large vessel occlusion. In cases without intracranial large vessel occlusion mechanical thrombectomy of acute ICAO is associated with a risk of distal embolization. More research on prognostic parameters is needed to better characterize the risk of decompensation of collateral flow and to better define the time-window of intervention. When mechanical thrombectomy fails or is not available, surgical approaches are an alternative in selected patients.

Prophylactic Ligature of AV Fistula Prevents High Output Heart Failure after Kidney Transplantation.

BACKGROUND: Arteriovenous (AV) fistulas are considered the gold standard for ensuring safe and long-term vascular access in patients with haemodialysis-dependent end-stage renal disease. However, previous studies demonstrated that high-flow AV fistulas might add additional cardiovascular burden in the post-transplant setting, leading to frequent fistula closure in this population. Currently, there is no consensus regarding management of high-flow fistulas in post-transplant patients with stable kidney function. The present randomized controlled trial examines the effect of prophylactic AV fistula closure on high-output heart failure. METHODS: Twenty-eight kidney transplant patients with stable graft function, absence of pre-existing severe cardiac failure, and brachial arterial flow rate of at least 1,500 mL/min were recruited and randomized in a 1:1 ratio to an intervention and control group, respectively. The intervention group was subject to immediate fistula ligature. Patients within the control group were referred to fistula ligature only if the main study endpoint high-output heart failure was reached. The latter was defined by the presence of at least 1 clinical sign (i.e., worsening NYHA score) and at least 2 of the following echocardiographic parameters: diameter of right atrium (major) >53 mm, right atrium (minor) >44 mm, inferior vena cava ≥21 mm, right pulmonary artery >20 mm, TAPSE <16 mm, systolic pulmonal artery pressure >40 mm Hg, and/or left ventricular eccentricity index <1. During a 24-month follow-up period, quarterly measurements of kidney function, NT-proBNP, and lactate dehydrogenase as well as a biannual echocardiographic check-up were performed. RESULTS: High-output heart failure attributable to high-flow fistula was reported in 5 of 13 control patients (38.5%), whereas no patient in the intervention group presented with clinical and echocardiographic signs of high-output heart failure during the follow-up period. Thus, prophylactic ligature of high-flow fistulas avoided high-output heart failure in our patient population (p = 0.013). Three patients in the control group, however, had to undergo fistula ligature due to aneurysm formation (n = 2) and steal phenomenon (n = 1). Median NT-proBNP levels decreased from 317 ng/L pre-ligature to 223 ng/L post-ligature (p = 0.003). Serum creatinine levels did not significantly differ before and after AV fistula ligature (1.69 vs. 1.60 mg/dL, respectively, p = 0.059). Improvement of echocardiographic findings (e.g., a decrease in systolic pulmonary arterial pressure) was found in 7 of 8 ligature patients but did not reach statistical significance. CONCLUSION: Prophylactic ligature of high-flow AV fistulas after kidney transplantation can avoid high-output heart failure, and a more liberal approach to close AV fistulas might be justified.

Ultrasound-Guided Fibrin Glue Injection for Treatment of Iatrogenic Femoral Pseudoaneurysms.

INTRODUCTION: Arterial pseudoaneurysms (PSAs) are the most common access site complication following transarterial catheter intervention. Ultrasound-guided injection of thrombogenic substances into perfused arterial PSAs followed by compression therapy is a well-established and less invasive treatment option than surgical repair. Different agents are available to induce thrombosis including thrombin and a fibrin-based tissue glue, which is used as first-line treatment at our institution. This paper deals with our experience using ultrasound-guided fibrin glue injection (UGFI). MATERIALS AND METHODS: Retrospective data analysis: all patients (55) treated for iatrogenic femoral PSA following digital subtraction angiography of the lower extremities between January 1, 2010, and December 31, 2018, were included. Data on epidemiology, PSA location and size, vascular risk factors, fibrin glue injection (fibrin glue volume), primary success rate of UFGI, and complications related to the treatment were analyzed. RESULTS: A total of 55 consecutive femoral iatrogenic PSAs were treated during the defined period and 32 (58.2%) of the patients were female. Imaging was performed using ultrasound in all cases. The most common PSA location (80.0%) was the common femoral artery, mean PSA size (± SD) was 2.7 ± 1.2 cm, and neck length was 1.6 ± 1.0 cm. The dose (mean ± SD) of fibrin glue was 2.6 mL (± 1.0; maximum: 6 mL). Primary UGFI success rate was 87.3% and conversion rate to open surgery was 12.7%. Two (4%) patients required embolectomy for peripheral embolization after UGFI. CONCLUSION: Early results achieved with UGFI for treatment of iatrogenic femoral PSA are promising. In our cohort, UGFI was a safe and effective first-line alternative to traditional open surgery, which then was unnecessary in the vast majority of PSA cases. Further prospective studies for comparison of ultrasound-guided techniques should be encouraged.