Habitat loss exacerbates pathogen spread : An Agent-based model of avian influenza infection in migratory waterfowl

Habitat availability determines the distribution of migratory waterfowl along their flyway, which further influences the transmission and spatial spread of avian influenza viruses (ATVs). The extensive habitat loss in the East Asian-Australasian Flyway (EAAF) may have potentially altered the virus spread and transmission, but those consequences are rarely studied. We constructed 6 fall migration networks that differed in their level of habitat loss, wherein an increase in habitat loss resulted in smaller networks with fewer sites and links. We integrated an agent-based model and a susceptible-infected-recovered model to simulate waterfowl migration and AIV transmission. We found that extensive habitat loss in the EAAF can 1) relocate the outbreaks northwards, responding to the distribution changes of wintering waterfowl geese, 2) increase the outbreak risk in remaining sites due to larger goose congregations, and 3) facilitate AIV transmission in the migratory population. In addition, our modeling output was in line with the predictions from the concept of "migratory escape", i.e., the migration allows the geese to "escape" from the location where infection risk is high, affecting the pattern of infection prevalence in the waterfowl population. Our modeling shed light on the potential consequences of habitat loss in spreading and transmitting AIV at the flyway scale and suggested the driving mechanisms behind these effects, indicating the importance of conservation in changing spatial and temporal patterns of AIV outbreaks.Peer reviewe

The Maastricht Acquisition Platform for Studying Mechanisms of Cell–Matrix Crosstalk (MAPEX):An Interdisciplinary and Systems Approach towards Understanding Thoracic Aortic Disease

Current management guidelines for ascending thoracic aortic aneurysms (aTAA) recommend intervention once ascending or sinus diameter reaches 5–5.5 cm or shows a growth rate of &gt;0.5 cm/year estimated from echo/CT/MRI. However, many aTAA dissections (aTAAD) occur in vessels with diameters below the surgical intervention threshold of &lt;55 mm. Moreover, during aTAA repair surgeons observe and experience considerable variations in tissue strength, thickness, and stiffness that appear not fully explained by patient risk factors. To improve the understanding of aTAA pathophysiology, we established a multi-disciplinary research infrastructure: The Maastricht acquisition platform for studying mechanisms of tissue–cell crosstalk (MAPEX). The explicit scientific focus of the platform is on the dynamic interactions between vascular smooth muscle cells and extracellular matrix (i.e., cell–matrix crosstalk), which play an essential role in aortic wall mechanical homeostasis. Accordingly, we consider pathophysiological influences of wall shear stress, wall stress, and smooth muscle cell phenotypic diversity and modulation. Co-registrations of hemodynamics and deep phenotyping at the histological and cell biology level are key innovations of our platform and are critical for understanding aneurysm formation and dissection at a fundamental level. The MAPEX platform enables the interpretation of the data in a well-defined clinical context and therefore has real potential for narrowing existing knowledge gaps. A better understanding of aortic mechanical homeostasis and its derangement may ultimately improve diagnostic and prognostic possibilities to identify and treat symptomatic and asymptomatic patients with existing and developing aneurysms.</p

Outcome of rectus femoris muscle flaps for groin coverage after vascular surgery

Objective: The aim of this retrospective cohort study was to investigate the outcome of rectus femoris muscle flaps (RFFs) for deep groin wound complications in vascular surgery patients and to compare the outcome with a cohort of sartorius muscle flaps (SMFs) because the RFF is a promising alternative technique for groin coverage. Methods: All RFFs and SMFs performed by vascular surgeons in a regional collaboration in The Southern Netherlands were retrospectively reviewed. Primary outcomes were muscle flap survival, overall and secondary graft salvage, and limb salvage. Secondary outcomes were 30-day groin wound complications and mortality, donor site and vascular complications, 1-year amputation-free survival, overall patient survival, impaired knee extensor function, and length of hospital stay. Results: A total of 96 RFFs were performed in 88 patients (mean age, 68 years; 67% male) and compared with a cohort of 30 SMFs in 28 patients (mean age, 64 years; 77% male). At a mean follow-up of 29 months and 23 months, respectively, comparable flap survival (94% vs 90%), secondary graft salvage (80% vs 92%), and limb salvage (89% vs 90%) rates were found. The 30-day mortality rates were 12% and 17%, respectively, and the 1-year amputation-free survival was comparable between treatment groups (71% vs 68%). Conclusions: This study presents a large series of RFFs for deep groin wound complications after vascular surgery. We demonstrate that muscle flap coverage using the rectus femoris muscle by vascular surgeons is an effective way to manage complex groin wound infections in a challenging group of patients, achieving similarly good results as the SMF

Fenestrated/Branched Endovascular Aortic Repair Using Unilateral Femoral Access in Patients with Iliac Occlusive Disease

OBJECTIVES: Fenestrated/branched endovascular aortic repair (F/BEVAR) in patients with occluded iliac arteries is challenging due to limited access for branch vessel catheterization and increased risk for leg and spinal ischemic complications. The aim of this study was to analyze technical strategies and outcomes of F/BEVAR in patients with unilateral iliofemoral occlusive disease (UIOD). METHODS: We performed a retrospective review of all consecutive patients treated by F/BEVAR in two institutions (2003-2021). Patients with UIOD were included in the analysis. All patients had one patent iliac artery which was used for advancement of the fenestrated-branch component. Preloaded catheter/guidewire systems or steerable sheaths were used as adjuncts to facilitate catheterization. Primary endpoints were technical success, mortality, major adverse events (MAEs: stroke, spinal cord injury, dialysis/GFR decline >50%, bowel ischemia, myocardial infarction or respiratory failure), primary iliac patency and freedom from reinterventions. RESULTS: There were 959 patients treated by F/BEVAR. Of these, 15 patients (1.56%, mean age 74, 80% male) had occluded iliac arteries and one patent iliofemoral access and were treated for a thoracoabdominal aortic aneurysm (8) or juxtarenal abdominal aortic aneurysm (7). Brachial access was used in 14/15 patients and preloaded systems in 7/15 patients (47%). The remaining 53% had staggered deployment of stent grafts. There were 7 physician-modified endovascular grafts, 7 custom-made devices and 1 off-the-shelf device used. Thirteen (87%) patients had distal seal using AUI stent-grafts and two (13%) had distal seal in the infrarenal aorta. Concomitant femoral crossover bypass (FCB) was performed in 2 patients and 6 patients had a prior FCB. Technical success was 100%. There were no intra-operative complications or early lower extremity ischemic complications and all FCB were preserved. There was one 30-day mortality (7%) due to retrograde type A dissection. MAEs occurred in 20% of patients. Median follow-up was 12 months (0-85). Two patients (13%) required three reinterventions. One patient required proximal stent-graft extension for an acute type B dissection (3 months) and another required iliac extension for type Ib endoleak of an AUI (21 months) and thrombolysis of that extension (50 months). At last follow-up all patients had primary graft patency except one with secondary graft patency without new claudication. One patient had a single renal artery stent occlusion at follow-up with no re-intervention. Overall survival was 60%, without aortic-related deaths. CONCLUSIONS: Although challenging, F/BEVAR with unilateral femoral/brachial approach is feasible in patients with occluded iliac limbs, with an important rate of ischemic complications but satisfactory outcomes