A cadaveric perfused model with antegrade arteriovenous pulsatile circulation: a new tool for teaching endovascular skills.

BACKGROUND: The benefits of using cadaveric humans in surgical training are well documented, and knowledge of the latest endovascular techniques is essential in the daily practice of vascular surgeons. Our study explores the feasibility of an affordable human cadaveric model with pulsatile and heated antegrade perfusion for reliable and reproducible endovascular or surgical simulation. METHODS: We undertook cannulation of 7 human cadavers embalmed in a saturated salt solution to create a left-to-right central perfusion with a heated solution, from the ascending thoracic aorta to the right atrium. To that end, we used surgically created carotidojugular and femorofemoral arteriovenous fistulas. Biomedical engineers designed a prototype pump for pulsatile circulation. We monitored invasive blood pressure and temperature. We used this model for training for endovascular thoracic aortic procedures and open vascular surgeries. RESULTS: The prototype pump achieved a pulsatile flow rate of 4.7 L/min. Effective cadaveric perfusion was achieved for several hours, not only with an arterioarterial pathway but also with arteriovenous circulation. The arterial pressures and in situ temperatures accurately restored vascular functions for life-like conditions. This new model made it possible to successfully perform thoracic endovascular aortic repair, subclavian artery stenting and simulation of abdominal open vascular trauma management. The saturated salt solution method and a specifically designed pump improved cost competitiveness. CONCLUSION: Endovascular simulation on human cadavers, optimized with the pulsatile and heated perfusion system, can be a dynamic adjunct for surgical training and familiarization with new devices. This reproducible teaching tool could be relevant in all surgery programs.

Appraising 5 years in activity of the largest public Canadian vascular graft bank.

BACKGROUND: In Canada, tissue distribution is managed by provincial entities. In 2014, Hema-Quebec established a cryopreserved vascular tissue bank accessible to all Canadian hospitals. The objectives of this report were to review the first 5 years of activity of Hema-Quebec's vascular bank and to briefly assess the competitiveness of its products. METHODS: Deceased donors, ages 15 to 60, were screened for common blood-borne diseases. Grafts were treated in a triple-antibiotic solution at 35°C before preservation at -100°C. Hema-Quebec's vascular graft records were analyzed from 2014 to 2019 inclusively. RESULTS: The average donor age was 35 years old and 78% of donors were men. Overall, 63% of harvested grafts cleared the quality management system. Positive microbial cultures and morphologic defects were the major reasons for graft discard. As such, a total of 60 grafts were delivered between 2016 and 2019 to 8 hospital centers. Moreover, the bank achieved a mean activity increase of 55% per year and Hema-Quebec's homografts were 48% less costly compared with similar homographs from for-profit organizations. CONCLUSIONS: Our findings demonstrate that Hema-Quebec has established a viable cryopreserved vascular tissue bank with steady increase in activity and an acceptable graft discard rates and pricing. Based on our findings, we recommend that efforts should be directed to expand the tissue bank graft distribution outside the province of Quebec.

Limb salvage after aneurysmal degeneration of a cryopreserved vein allograft: Searching the autologous veins of the arm is worth the effort.

CLINICAL DATA: We hereby report a case of limb salvage involving a 64-year-old man who was hospitalized with ischemic foot ulcers for two months. Endarterectomy with patching and stenting of the left iliofemoral artery failed. A composite bypass of two segments of the endarterectomized superficial femoral artery and a cryopreserved saphenous vein graft was implanted one week later. On day 4 postoperatively, an infection (Staphylococcus epidermidis and Pseudomonas aeruginosa) was treated empirically with antibiotics. Four months later, the femoro-tibial bypass thrombosed and the patency was restored by thrombolysis. The aneurysmal cryopreserved vein was excised. Iterative complications followed and final success was attained after implantation of autologous cephalic and basilic veins. Four years later, this femoro-tibial is still patent. PATHOLOGICAL ANALYSES: After a gross observation, the explant was dissected and the most significant sections were processed for histology, followed by analyses in scanning electron microscopy, light microscopy and transmission electron microscopy. RESULTS: The explanted specimen showed a smooth flow surface proximally but a severe distortion distally, with an accumulation of poorly organized mural thrombi. The wall of the arterialized vein was accompanied with an important inflammatory reaction. The degradation of the collagen structure was evidenced in TEM. The fibrils of collagen were still individualized but were fragmented and did not display parallelly. The regular banding was preserved. The presence of Pseudomonas aeruginosa was shown inside the wall of the homologous vein. COMMENTS: In case of sepsis, the most aggressive antibiotic treatments cannot fully eliminate the bacteremic colonizations within the wall of an alternative conduit. The cephalic and basilic autologous veins are proved to be preferable in absence of the autologous saphenous vein. The amputation was prevented and four years later the bypass is still patent. This is an outstanding result based upon the comorbidities of the patient. The most aggressive harvesting shall be recommended. This patient represented a considerable challenge and the clinical result is highly gratifying: the search for the autologous cephalic and basilic veins proved to be worth the effort.

Hybrid repair of a hepatic artery aneurysm.

Visceral arterial aneurysm is a rare pathology. Currently, there are no sufficient data to support the superiority of surgical or endovascular treatment. The choice depends mainly on patient characteristics and the anatomy of the aneurysm. We present a case of a 12-cm fusiform aneurysm of the common hepatic artery. A combined approach including endovascular exclusion of the celiac trunk and surgical closure of the aneurysm was chosen. The postoperative course was uneventful. To our knowledge, this is the first case in the literature describing this combined approach.

Open repair of vertebral artery: a 7-year single-center report.

BACKGROUND: To report the long-term results of proximal and distal VA open repairs. METHODS: From January 2002 to December 2009, 74 cases of VA open repair were performed (73 patients, 41 men; mean age, 66.5 ± 15.2 years). Symptoms of vertebrobasilar insufficiency were present in 61 cases (82.4%). Forty-seven have had a proximal VA repair, and 27, a distal one. Bypass grafting using a saphenous vein graft was performed in 21 cases (28.3%). Direct transposition was used in 48 (64.8%), mostly into the common carotid artery. RESULTS: Mean duration of follow-up was 39.5 ± 31.3 months. A stroke was present in three patients (4.1%), two hemispheric (2.7%) and one vertebrobasilar (1.3%), which turned lethal. The two hemispheric strokes occurred in the subgroup of 35 procedures combined with a carotid artery reconstruction. A transient Horner syndrome was found in 16 cases (21.6%), and a transient vocal palsy, in six (8.1%). Early postoperative occlusion occurred in two cases (2.7%). A total of seven (9.4%) patients died during follow-up, one from a stroke. Cumulative Kaplan-Meier survival rate was 90.7 ± 4.8% at 3 years and 77.3 ± 12.2% at 6 years. Assessment of late patency was obtained in 54 (84.3%) of 64 survivals by duplex scanning (70.3%) or angiography (10.9%). Significant vertebrobasilar symptom-free rate was 87.7 ± 9.2% at 6 years. Primary patency rate was 94.8 ± 3.8% at 3 years and 90.8 ± 9.4% at 6 years. CONCLUSIONS: VA open repair provides excellent long-term results. Patients with combined carotid and VA reconstruction are at higher risk of postoperative stroke than patients undergoing isolated repair of the VA.

Characterization of visual manifestations and identification of risk factors for permanent vision loss in patients with giant cell arteritis.

BACKGROUND/PURPOSE: Permanent vision loss (PVL) is a feared complication and a leading cause of morbidity in giant cell arteritis (GCA). The objective of this study is to describe visual manifestations and identify risk factors of ocular involvement in GCA. METHODS: A retrospective database from a single vasculitis referral center was used. Descriptive statistics comparing patients with and without ocular involvement were performed. RESULTS: One hundred patients with GCA were included. Visual symptoms were present in 53% of patients at diagnosis and included blurred vision (30%), diplopia (16%), amaurosis fugax (14%), and blindness (19%). Out of 19 patients with blindness, 16 did not recover and had PVL. Patients with PVL were older (79.2 ± 6.7 vs 74.2 ± 7.6 years; p = 0.008) and more likely to have coronary artery disease (31% vs 10%; p = 0.018). However, they were less likely to have other cranial symptoms (81% vs 96%; p = 0.019), mainly headaches (64% vs 92%; p = 0.003). Risk factors associated with an abnormal ophthalmologic examination were the same as for PVL, but patients were also more likely to have diabetes (29% vs 7%; p = 0.040) and less likely to have constitutional symptoms (53% vs 80%; p = 0.033). CONCLUSION: Patients with GCA and ocular involvement were more likely to have baseline diabetes and atherosclerosis. A predisposing vascular vulnerability might therefore increase the risk of ocular involvement. Key points • Most patients with GCA and complete vision loss at presentation will not recover and evolve to have permanent vision loss. • A GCA patient with visual manifestations at presentation has more baseline vascular risk factors (diabetes, atherosclerosis) than patients without ocular involvement. • Patients with GCA and visual manifestations have fewer constitutional symptoms and lower inflammatory markers than patients without ocular involvement.

Colour Doppler ultrasound and the giant cell arteritis probability score for the diagnosis of giant cell arteritis: a Canadian single-centre experience.

OBJECTIVES: The aim was to compare the accuracy of colour Doppler ultrasonography (CDUS) and temporal artery biopsy (TAB) to establish the final diagnosis of GCA and to determine how the GCA probability score (GCAPS) performs as a risk stratification tool. METHODS: Descriptive statistics were performed on a retrospective cohort of patients referred to our vasculitis referral centre between 1 July 2017 and 1 October 2020 for suspected GCA. CDUS, TAB, centre-specific TAB (vasculitis centre vs referring hospitals) and GCAPS were compared against the final diagnosis of GCA as determined by a GCA expert; CDUS was also compared with TAB results. RESULTS: Data from 198 patients were included: 60 patients with GCA and 138 patients without GCA. Sixty-two patients had a TAB. Using the final diagnosis by a GCA expert as a reference, the sensitivity, specificity, positive predictive value and negative predictive value were 93.3%, 98.5%, 96.6% and 97.1% for CDUS and 69.2%, 100%, 100% and 81.8% for TAB, respectively. The false-negative rate was 6.7% for CDUS and 30.8% for TAB. False-negative TAB mostly occurred when performed in referring hospitals (57.1%) as opposed to our vasculitis centre (21.1%). With a cut-off at 9.5 points, sensitivity for GCAPS was 98.3% and specificity 74.3%. CONCLUSION: CDUS of the temporal and axillary arteries showed a high sensitivity and specificity and helped to diagnose GCA in patients with negative TAB. We validated that GCAPS is a useful clinical tool, with a score of <9.5 making the diagnosis of GCA improbable.

FR167653 improves renal recovery and decreases inflammation and fibrosis after renal ischemia reperfusion injury.

OBJECTIVE: Acute tubular necrosis (ATN) secondary to induced warm ischemia (WI) results in inflammatory and delayed fibrotic processes and remains a common clinical problem with serious consequences. Because tumor necrosis factor-alpha (TNF-alpha) is a prominent proinflammatory factor implicated in the pathophysiology of acute renal ischemia reperfusion injury (IRI), we hypothesized that FR167653 (FR), a potent inhibitor of TNF-alpha and interleukin-1beta production, may reduce IRI. METHODS: IRI was induced in male pigs by bilateral clamping of the renal pedicle for 90 minutes (WI90), or unilateral renal clamping (90 minutes) after contralateral nephrectomy (1/2Nx90), or unilateral renal clamping without contralateral nephrectomy (WIuni90). FR was administered intravenously 60 minutes before WI (1 mg/kg/h), during WI, and continuously for 3 hours (1 mg/kg/h) during reperfusion in treated groups (FRWI90, FR1/2Nx90, or FRWIuni90). Blood and urine samples were collected between day 1 and 3 months after reperfusion for assessment of renal function. Kidneys were excised and renal tissues were collected at 3 months for morphologic and inflammation evaluation and protein analysis. Experimental groups were compared with sham operated (control) and heminephrectomized (Unif) groups without renal ischemia. RESULTS: Three WI90 animals (43%) and five 1/2Nx90 (70%) were euthanized and necropsied at day 7 because of no urine production or poor conditions. Mortality was significantly improved after FR treatment. Survival was 100% in the control, Unif, WIuni90, and FR groups. In Unif groups, FR significantly reduced renal failure and bilateral renal ischemia (P < .05). At 3 months, proteinuria was significantly reduced in FR-treated groups (P < .01). Inflammatory cells count was also dramatically diminished in FR-treated pigs (P < .01 for CD3-positive cells). The second aspect of transient ischemia is the fibrotic process determined at 3 months. FR treatment was characterized by a reduction of renal fibrosis, particularly in Unif groups. TNF-alpha protein expression was diminished in FR-treated groups. CONCLUSION: This is the first evidence that FR reduced the early and long-term effect of WI in the severe ischemia model. This effect was particularly marked against fibrosis and inflammation, which would contribute to deterioration of a patient's renal function.

Influence of warm ischemia time on peripheral-type benzodiazepine receptor: a new aspect of the role of mitochondria.

The peripheral benzodiazepine receptor (PBR) is located mainly in the outer mitochondrial membrane and many functions are associated directly or indirectly with the PBR. We have studied the influence of different durations of warm ischemia (WI) on renal function, tissue damage and PBR expression in a Large Whitepig model. After a midline incision, the renal pedicle was clamped for 10 (WI10), 30 (WI30), 45 (WI45), 60 (WI60) or 90 min (WI90), and blood and renal tissue samples were collected between 1 day and 2 weeks after reperfusion for assessment of renal function. Metabolite excretion associated with renal ischemia reperfusion injury such as trimethylamine-N-oxide (TMAO) was quantified in blood by magnetic resonance spectroscopy. PBR mRNA and protein expression were determined in renal tissue. TMAO levels rose progressively and significantly with increasing duration of WI. PBR mRNA expression was upregulated between 3 h and 1 day after reperfusion in WI30, WI45 and WI60. Its upregulation was noted 3 days after reperfusion in WI90. At day 14, PBR transcript expression was not different from basal level in any group. PBR protein followed the same pattern. These findings suggest a new role for PBR which could be a major target in the regeneration process during ischemia reperfusion.

Acute compartment syndrome following fibula flap harvest for mandibular reconstruction.

Donor site morbidity for free fibula osteofasciocutaneous flaps has rarely been reported in the literature. We report on a case of acute compartment syndrome (ACS) in a 22-year-old male, following fibula flap harvest for mandibular reconstruction and arising after post-ischemic reperfusion damage. Dissection during this patient's surgery was unusually difficult. The skin defect was covered with a loose dressing while waiting for secondary grafting. Intracompartmental pressures measured by the Wick catheter technique confirmed the diagnosis of ACS. ACS is an unexpected complication after fibula flap harvest since the three compartments of the leg are opened during surgery. Only four cases of ACS have been reported in the literature. Analysis of this serious complication might lead to changes in the routine use of the pneumatic tourniquet in some selected cases. New automatic tourniquet systems might also be advantageous in such cases.

Carotid bypass with polytetrafluoroethylene grafts: a study of 110 consecutive patients.

BACKGROUND: Carotid endarterectomy (CEA) is the standard treatment for atherosclerotic lesions involving the carotid bifurcation. However, CEA can be challenging under some conditions. We describe the technique and outcome of prosthetic carotid bypass grafting (PCB) with polytetrafluoroethylene (PTFE) grafts as an elective alternative to CEA. PATIENTS AND METHODS: This retrospective analysis of prospectively collected data came from a series of 110 consecutive PCBs, that is, 9.6% of 1140 carotid revascularization procedures performed in our department between September 1986 and July 2002. Primary indications for PCB were extensive atherosclerotic lesions (n = 45, 40.9%), carotid stenosis associated with kinking (n = 29, 26.4%), recurrent stenosis (n = 18, 16.4%), and stenosis after radiation therapy (n = 7, 6.4%). RESULTS: The combined stroke and death rate at 30 days was 0.9%. Mean duration of follow-up was 647 +/- 71 days. Four carotid bypass grafts (3.6%) became occluded, and stenosis recurred in 1 (0.9%). At 3 years, overall actuarial survival was 81.4 +/- 11.5 and actuarial stroke-free rate was 97.7 +/- 2.3. There were no fatal strokes. CONCLUSION: PCB is a viable technique for treatment of extensive atherosclerotic carotid lesions, recurrent carotid stenosis, and carotid stenosis after radiation therapy. Postoperative stroke, occlusion, and recurrent stenosis rates are comparable to those associated with CEA performed under optimal conditions.