Radiolabelled leucocyte scintigraphy versus conventional radiological imaging for the management of late, low-grade vascular prosthesis infections.

PURPOSE: In this study we evaluated the diagnostic performance of (99m)Tc-HMPAO-leucocyte ((99m)Tc-HMPAO-WBC) scintigraphy in a consecutive series of 55 patients (46 men and 9 women, mean age 71 ± 9 years, range 50 - 88 years) with a suspected late or a low-grade late vascular prosthesis infection (VPI), also comparing the diagnostic accuracy of WBC with that of other radiological imaging methods. METHODS: All patients suspected of having VPI underwent clinical examination, blood tests, microbiology, US and CT, and were classified according to the Fitzgerald criteria. A final diagnosis of VPI was established in 47 of the 55 patients, with microbiological confirmation after surgical removal of the prosthesis in 36 of the 47. In the 11 patients with major contraindications to surgery, the final diagnosis was based on microbiology and clinical follow-up of at least 18 months. RESULTS: (99m)Tc-HMPAO-WBC planar, SPECT and SPECT/CT imaging identified VPI in 43 of 47 patients (20 of these also showed infection at extra-prosthetic sites). In the remaining eight patients without VPI, different sites of infections were found. The use of SPECT/CT images led to a significant reduction in the number of false-positive findings in 37% of patients (sensitivity and specificity 100 %, versus 85.1% and 62.5% for stand-alone SPECT). Sensitivity and specificity were 34% and 75% for US, 48.9% and 83.3% for CT, and 68.1% and 62.5% for the FitzGerald classification. Perioperative mortality was 5.5%, mid-term mortality 12%, and long-term mortality 27%. Survival rates were similar in patients treated with surgery and antimicrobial therapy compared to patients treated with antimicrobial therapy alone (61% versus 63%, respectively), while infection eradication at 12 months was significantly higher following surgery (83.3% versus 45.5%). CONCLUSION: (99m)Tc-HMPAO-WBC SPECT/CT is useful for detecting, localizing and defining the extent of graft infection in patients with late and low-grade late VPI with inconclusive radiological findings. (99m)Tc-HMPAO-WBC SPECT/CT might be used to optimize patient management.

Simultaneous tracking of catheters and guidewires: comparison to standard fluoroscopic guidance for arterial cannulation.

OBJECTIVES: The purpose of this in vitro study was to clinically assess the feasibility of a three-dimensional (3D) electromagnetic (EM) navigator, including sensorized catheters and guidewires, to determine any reduction in radiation dose and contrast medium injection. METHODS: The study was performed using a navigator prototype developed at the EndoCAS center. The system includes catheters and guidewires simultaneously tracked with an EM localizer (Aurora, Northern Digital, Waterloo, Canada). Tests were performed on a commercial abdominal aortic aneurysm model. Fifteen operators were asked to cannulate renal arteries using the conventional fluoroscopic guidance and the EM navigator without fluoroscopic support. Each trial was video-recorded and analyzed for timing and success of completing the cannulation task by two blinded and independent observers. Performances were also qualitatively evaluated using the Imperial College Endovascular Cannulation Scoring Tool (IC3ST). Moreover, a questionnaire was administered to participants to evaluate the navigator potentialities. RESULTS: Quantitative analysis results show no significant difference between the fluoroscopic and EM guidance regarding the total procedure time (median 2.36 minutes [interquartile range {IQR} = 1.26-4.7) vs. 2.95 min [IQR = 1.35-5.38], respectively; p = .93); number of total hits with catheter/guidewire tip to vessels wall (median 5.50 [IQR = 2.00-10.00] vs. 3.50 [IQR = 2.50-7.00], respectively; p = .65); and number of attempts at cannulation (median 4.0 [IQR = 2.00-5.00] vs. 4.0 [IQR = 2.00-5.00], respectively; p = .72]. Moreover, there was no significant difference between the IC3ST score obtained using the EM navigator and the traditional method (average 22.37 [STD = 7.95] vs. 21.58 [STD = 6.86]; p = .92). Finally, questionnaire results indicate a general agreement concerning the navigator usefulness, which clearly shows the positions of instruments inside the 3D model of the patient's anatomy. Participants also agreed that the navigator can reduce the amount of contrast media delivered to the patient, as well as fluoroscopy time. CONCLUSIONS: This work provides proof of concept that simultaneous EM navigation of guidewires and catheters is feasible without the use of live fluoroscopic images.

Inflammatory popliteal aneurysm associated with SARS-CoV-2 infection.

BACKGROUND: SARS-CoV-2 infection involves the phase of viral replication and inflammatory response predicting the severity of COVID-19. Vascular involvement in SARS-CoV-2 infection has been well established. Thrombotic complications are common, while only few cases of dilatative diseases have been reported. CASE REPORT: We herein report the case of a 65-year-old male patient with an inflammatory 25-mm saccular popliteal artery aneurysm detected six months after symptomatic COVID-19 (pneumonia, and pulmonary embolism). The popliteal aneurysm was surgically managed with aneurysmectomy, and reversed bifurcated vein graft. Histological examination detected the infiltration of monocytes and lymphoid cells into the arterial wall. CONCLUSIONS: Popliteal aneurysm could be related to inflammatory response related to SARS-CoV-2 infection. The aneurysmal disease should be considered mycotic and surgically managed without prosthetic grafts.

A Systematic Review on Methods and Tools for the In Situ Fenestration of Aortic Stent-Graft.

In situ fenestration of stent-graft represents a potential option for the treatment of aortic diseases in patients unsuitable for standard endovascular repair. The best fenestration strategy to restore perfusion of collateral vessels after their coverage by an endograft depends mainly on the anatomical area. Several tools are employed as fenestration devices, including needles, radiofrequency probes, and laser systems, used in conjunction with other instrumentation to provide enough support and stability during the procedure. In this systematic review, the approaches to reach the correct fenestration site both in human, animal, and in in vitro environments are described and discussed, highlighting advantages and limitations. Both commercial and dedicated solutions for the intraoperative modification of the fabric material are reported as well. The clinical interest in this procedure has so far encouraged researchers to develop and refine both methods and tools to solve the current limitations of this technique, intending to extend the indications for endovascular treatment to a broader range of patients.

Listeria abdominal endograft infection miming pseudoaneurysm treated with in-situ aortic reconstruction: a case report.

We report the case of a 72-year old man previously treated with an aortic endograft for an abdominal aortic aneurysm. After 3 years the patient developed a sepsis. Imaging and blood exams detected an endograft infection related to Listeria monocytogenes. Patients underwent endograft removal and in-situ aortic reconstruction with a cryopreserved allograft. A continuous antibacterial therapy has been established. One-month follow-up revealed the absence of clinically relevant infection with patency of the graft and absence of biochemical inflammatory markers.

A rare case of mycobacterial pseudoaneurysm of the superficial femoral artery.

OBJECTIVE: Extrapulmonary localization of tuberculosis accounts for about 15-20% of cases. Several cases of Mycobacterium tuberculosis with vascular involvement have been described, but only few cases for limb vessels. CASE REPORT: We report the case of a 33-year-old man from Gambia with a symptomatic pseudoaneurysm of the right superficial femoral artery. Total body positron emission tomography/computed tomography with [18F]FDG revealed an active infection. The patient underwent vascular reconstruction with a straight reversed vein graft. Molecular testing for Mycobacterium tuberculosis was non-diagnostic. Cultures of the pseudoaneurysm wall and thrombus removed during surgery grew Mycobacterium tuberculosis. CONCLUSIONS: The diagnosis of vascular tuberculosis infection due to Mycobacterium tuberculosis is a challenge. Epidemiology remains the primary criterion for maintaining a high index of suspicion.

Novel EM Guided Endovascular Instrumentation for In Situ Endograft Fenestration.

Objective: This work aims at providing novel endovascular instrumentation to overcome current technical limitations of in situ endograft fenestration including challenges in targeting the fenestration site under fluoroscopic control and supplying mechanical support during endograft perforation. Technology: Novel electromagnetically trackable instruments were developed to facilitate the navigation of the fenestration device and its stabilization at the target site. In vitro trials were performed to preliminary evaluate the proposed instrumentation for the antegrade in situ fenestration of an aortic endograft, using a laser guidewire designed ad hoc and the sharp end of a commercial endovascular guidewire. Results: In situ fenestration was successfully performed in 22 trials. A total of two laser tools were employed since an over bending of laser guidewire tip, due to its manufacturing, caused the damage of the sensor in the first device used. Conclusions: Preliminary in vitro trials demonstrate the feasibility of the proposed instrumentation which could widespread the procedure for in situ fenestration. The results obtained should be validated performing animal studies. Clinical Impact: The proposed instrumentation has the potential to expand indications for standard endovascular aneurysm repair to cases of acute syndromes.

Hybrid procedures and femoral endarterectomy in diabetic patients.

OBJECTIVE: The aim of the study is to evaluate the safety and effectiveness of common femoral endarterectomy (CFE) in critical limb ischemia (CLI) associated with proximal and distal endovascular (EV) revascularization in diabetic (type 1 and type 2) and non-diabetic patients. PATIENTS AND METHODS: We analyzed patients from January 2008 to December 2011 who underwent one-staged hybrid procedures. Patients were divided into three groups: group 1 = EV reconstruction proximal to the CFE, group 2 = EV procedures distal to the CFE, group 3 = both proximal and distal EV procedures. Patients were evaluated at 6 and 36 months after the procedures, and the mean follow-up was 42 ± 20.3 months. RESULTS: A total of 43 (79% men; aged 74.4 ± 8.6 years) out of 635 (5.5%) patients operated for CLI fulfilled the inclusion criteria; 23 (53.5%) had type 1 or type 2 diabetes mellitus (DM). DM patients were younger than controls (p = 0.048). The patient distribution was 14 in Group 1 (32.5%), 24 in Group 2 (55.8%) and 5 in Group 3 (11.7%). CFE was successful in all cases, while associated EV procedures were successful in 90.7% of patients. Peri-operative morbidity and mortality were 11.6% and 2.3%, respectively. Survival rates at 6 and 36 months were 93% and 71.9%, respectively. Three patients (6.98%) underwent a major amputation. The cumulative limb salvage was 95.2% at 6 months and 92.1% at 36 months. No recurrent CFE stenosis was observed. No differences in survival, amputation or patency rates emerged between DM and non-DM patients or among the three EV revascularization groups. CONCLUSIONS: Hybrid procedures are safe and effective both in CLI patients with or without DM, and they should be taken into consideration whenever indications are present.

Postsurgical antithrombotic therapy in microsurgery: our protocol and literature review.

OBJECTIVE: Despite the improvements reached by microsurgeons in the last 30 years, postoperative complications still occur and most of them are the result of venous thrombosis at the pedicle anastomosis. Primary prevention of thrombosis is mandatory and anticoagulant therapy in the preoperative and postoperative period is widely used. Still, there is a lack of consensus in the literature about the best postoperative protocol for microsurgical reconstruction. The authors aimed to review the postoperative antithrombotic regimens described in literature focusing on their effects and risks, and moreover, share their experience. MATERIALS AND METHODS: The authors performed a literature review of postsurgical antithrombotic protocols applied in reconstructive microsurgery. Research on PubMed server was performed typing the terms "antithrombotic", "postoperative", "microsurgery", "free flap pedicle", "anticlotting", "anticoagulant". RESULTS: The authors described the postoperative standardized pro-weight pharmacological protocol applied in their unit: a combination of dextran and heparin. They inhibit more than one pattern of coagulation in order to stop platelet aggregation and thrombin action and, in the meantime, contending fluid loss with plasma expansion. CONCLUSIONS: Nowadays, a non-standardized practice, based on experience, is applied by microsurgeons in postsurgical care; the authors performed a review of the combined antithrombotic therapies described in the literature. A standardized pro-weight pharmacological protocol is proposed; it allows to increase blood flow by volume expander action (Dextran) and thrombin inhibition (Heparin). Still, coagulation cascade and platelet function have a wide variability among humans, as well as the effect of drugs. Achieving an optimal antithrombotic effect and minimizing adverse reactions meantime remains a challenge.

Long-term survival of patients with critical limb ischemia treated with iloprost: response rate and predictive criteria. A retrospective analysis of 102 patients.

OBJECTIVE: Critical limb ischemia (CLI) patients have poor long-term prognosis. We showed that iloprost improves outcomes (major amputation and survival) up a 5-year follow-up, but it is not known if in this length of time the survival curves, of clinical responders and non-responders, differ. PATIENTS AND METHODS: A retrospective study enrolling 102 consecutive patients between 2004-2008, with clinical and instrumental (ultrasound, angiography, transcutaneous tensiometry of oxygen TcpO2 and carbon dioxide TcpCO2 in the affected and contralateral limbs) diagnosis of critical ischemia. All patients received the best medical therapy. Iloprost was administered (0.5-2 ng/kg/min 6 hours/day for 2-4 weeks) in all patients initially considered unsuitable for revascularization, repeating it regularly in time every six-twelve months in the case of positive response. The minimum expected follow-up was 4 years. RESULTS: 71.5% of patients were treated with iloprost and the responder rate was 71.2%. Most of the patients were regularly retreated with repeated cycles. Initial median supine TcpCO2 in symptomatic limb was higher in untreated patients than those treated (58 vs. 49 mmHg; p < 0.05) and in non-responders compared to responders (60 vs. 49 mmHg; p < 0.05). TcpCO2 directly and significantly correlated with the highest risk of mortality and seems to represent a new accurate prognostic criterion of unfavourable short and long-term response to prostanoid. In iloprost group, major amputations were significantly reduced. Revascularization was significantly higher in non-responders (57.1% vs. 11.5%; p < 0.05). There was a significantly higher prevalence of subsequent myocardial infarction in the non-iloprost group (27.6% vs. 9.6%; p < 0.05). The survival rate of non-responders was higher than untreated up until the second year (76.2% vs. 62%; p < 0.05). At 4 years we found higher survival in patients treated with iloprost (64.3% vs. 41% in untreated; p < 0.05) and in responders (75% vs. 38.1% in non-responders; p < 0.05). CONCLUSIONS: Our results confirm the favourable role of iloprost on the long-term outcome in patients with CLI. In particular, the maximum benefit is obtained in responder patients treated with multiple cycles of infusion.

Long-term clinical outcomes in critical limb ischemia--A retrospective study of 181 patients.

OBJECTIVE: Critical limb ischemia (CLI) is the most severe manifestation of the peripheral arterial disease. To date, several prognostic factors have been identified but the data of long-term follow-up in real life setting are scarce. The aim of our study is to describe a large group of CLI patients and identify possible prognostic factors, in a long-term follow-up. PATIENTS AND METHODS: Case-control, retrospective study. 181 consecutive CLI patients with a minimum follow-up of 5 years were included in the study. RESULTS: Overall mortality was 15%, 24%, and 43% at 1, 2, and 5 years, respectively. Among known risk factors, only arterial hypertension was significantly correlated with survival rate; no differences were found between diabetics and non-diabetics. Patients treated with intravenous iloprost (46%), compared to untreated patients, showed a better (p < 0.0001) long-term outcome in terms of major amputation (6% vs. 21%), subsequent vascular surgery (4% vs. 32%) and survival rates (69% vs. 47%), at 5-year follow-up. Major amputations were significantly correlated with lower median forefoot transcutaneous values of O2 (0/3 mmHg, p < 0.001) and higher median values of CO2 (83/53 mmHg, p < 0.0001) in supine/dependent position, respectively. CONCLUSIONS: Our results confirm the poor prognosis of CLI patients in a very long-term follow-up and the severe metabolic damage caused by ischemia. A favourable role of iloprost was observed, in agreement with previous evidence in the literature.

Small-bowel obstruction due to Bezoar following pancreas transplantation with portal-enteric drainage: a case report.

BACKGROUND: Despite recent improvements, surgical complications continue to occur frequently after pancreas transplantation, remaining the leading cause of early graft loss. Small-bowel obstruction, however, is exceedingly rare; it has not been associated with an enhanced risk of graft loss. METHODS: Intestinal obstruction occurred 7 days after pancreas transplantation due to bezoar blockage at the level of the jejunojejunostomy of the Roux-en-Y loop, which had been constructed to drain the exocrine secretions of the pancreas graft. RESULTS: CT scan promptly identified the foreign body and greatly facilitated graft rescue before duodenal rupture or the development of graft pancreatitis. Nineteen months after repeat laparotomy the patient is alive with good pancreatic endocrine function. CONCLUSIONS: In cases of pancreas transplantation with enteric drainage, obstruction of the Roux-en-Y loop may create a totally sealed system that may lead to severe duodenal dilation and eventually to duodenal rupture or graft pancreatitis.

Rescue of kidney and pancreas grafts with complex vascular lesions.

BACKGROUND: The organ shortage mandates that grafts with complex vascular lesions be considered for graft rescue. METHODS: Surgical graft rescue was attempted in 8 patients bearing 8 kidneys and 2 pancreata that showed complex vascular lesions deemed not suitable for interventional radiology procedures. RESULTS: All procedures but 1 were performed under elective conditions. Seven grafts were repaired in situ, while cooling the organ through retrograde venous perfusion, and 3 kidneys were explanted, repaired extracorporeally, and retransplanted. All vascular reconstructions remain patent after a mean follow-up period of 3.3 years (+/-2.1 years). CONCLUSIONS: Careful patient selection, multidisciplinary evaluation, and personalized surgical technique may allow the rescue of kidney and pancreas grafts with complex vascular lesions that, otherwise, would be lost.

A new pericardium vascular prosthesis: mechanical behavior, SEM analyses and clinical indications.

This study deals with the mechanical characterization of a new vascular prosthesis. The prosthesis, made from a single portion of pericardial tissue, is bifurcated, crimped and not porous. The clinical use of this graft could increase hemocompatibility of the device compared to polymeric grafts and reduce the compliance mismatch between the natural vessel and the graft. Several mechanical analyses were performed to evaluate the load-displacement and the cyclic loading characteristics of the graft. Scanning electron microscopy was used to evaluate the tissue and suture line morphology before and after mechanical failure. The preliminary results of some clinical cases are also reported. The results point out that the prostheses, developed using correct technological procedures, show a mechanical behavior similar to that of natural arteries and could be successfully used in selected patients.

Electromagnetic navigation platform for endovascular surgery: how to develop sensorized catheters and guidewires.

BACKGROUND: Endovascular procedures are nowadays limited by difficulties arising from the use of 2D images and are associated with dangerous X-ray exposure and the injection of nephrotoxic contrast medium. METHODS: An electromagnetic navigator is proposed to guide endovascular procedures with reduced radiation dose and contrast medium injection. Five DOF electromagnetic sensors are calibrated and used to track in real time the positions and orientation of endovascular catheters and guidewires, while intraoperative 3D rotational angiography is used to acquire 3D models of patient anatomy. A preliminary prototype is developed to prove the feasibility of the system using an anthropomorphic phantom. RESULTS: The spatial accuracy of the system was evaluated during 70 targeting trials obtaining an overall accuracy of 1.2 ± 0.3 mm; system usability was positively evaluated by three surgeons. CONCLUSIONS: The strategy proposed to sensorize endovascular instruments paves the way for the development of surgical strategies with reduced radiation dose and contrast medium injection. Further in vitro, animal and clinical experiments are necessary for complete surgical validation.

Surgical treatment of persistent type 2 endoleaks, with increase of the aneurysm sac: indications and technical notes.

OBJECTIVE: Unsolved type 2 endoleaks and aneurysmal sac increasing after endovascular aneurysm repair (EVAR) can be fixed with surgical sacotomy, ligation of the patent backbleeding vessels and preservation of the endograft. The aim of the paper is to highlight the technique as a feasible procedure in alternative to the removal of the graft. MATERIALS AND METHODS: Four male patients whose aneurysm sac maximum transverse diameter had increased by 5 mm or more, without evidence of endoleak, migration or structural alteration of the endografts. The surgical access was by medial laparotomy in one case, flank incision in two cases and mini-laparotomy with laparoscopic assistance in the fourth case. Patients were followed with spiral CT and duplex ultrasound at discharge and at 6-12 months. RESULTS: All procedures were carried out, without complication. Two patients required intensive care unit (ICU) admission and the average post-operative hospital stay was 10 days (range 6-13). All patients are currently alive with a functioning endograft, at an average follow-up of 14.7 months. CONCLUSIONS: Sacotomy, leaving the endograft in place, appears to be a feasible therapeutic option, less invasive than conversion to open repair. This technique merits further study.

Renal hypertension due to giant perirenal haematoma: permanent resolution by percutaneous ultrasound-guided drainage.

We describe a case of renovascular hypertension accompanied by renal failure, arising in a young man with a solitary kidney 4 months after a blunt abdominal trauma. A giant haematoma was found around the right kidney and ultrasound-guided percutaneous drainage completely relieved the symptom complex. Nine years later, the patient is normotensive with normal renal function.

Transcutaneous oxygen and carbon dioxide during treatment of critical limb ischemia with iloprost, a prostacyclin derivative.

The effect of intravenous iloprost treatment (median rate: 1.6; range 1-2 ng/kg/min; 6 h daily over 4 weeks) on transcutaneous pO2 and pCO2 was studied in 8 patients with bilateral peripheral obstructive arterial disease and monolateral critical limb ischemia. Tensiometric determinations were obtained at both metatarsi in the supine and dependent position. In critically ischemic limbs, supine transcutaneous p)2 changed erratically during iloprost treatment, increasing in only three out of eight lower limbs. At variance with its inconsistent behavior in the supine position, dependent pO2 increased during drug administration (p<0.02). Transcutaneous pCO2 was unchanged by iloprost. In the contralateral, non-symptomatic limb, both supine and dependent pO2 values were increased by the drug, suggesting that systemic hemodynamic changes may participate in its effect on transcutaneous gas tension, even at infusion rates clinically titrated to avoid evident changes in blood pressure and heart rate.

Fibrinogen and mortality in chronic critical limb ischaemia.

OBJECTIVE: Plasma fibrinogen predicts cardiovascular events in patients with stable peripheral arterial occlusive disease, but its predictive value in patients with chronic critical limb ischaemia, a condition associated with a high risk of death, is unknown. DESIGN: A prospective cohort study. SETTING: Determination of fibrinogen and other potential predictors during clinic-based work-up of patients admitted for diagnostic and therapeutic evaluation. SUBJECTS: A total of 108 patients (72 +/- 10 years, 78 males) with atherosclerotic occlusive disease and critical limb ischaemia (pain at rest and/or trophic lesions) followed up for a median period of 1.6 years). (range: 8 days-5.5 years; 218 patient-years). MAIN OUTCOME MEASURES: Total mortality. RESULTS: Forty-five deaths (71% cardiovascular) occurred during the follow-up. Baseline fibrinogen was higher in those who died in the early follow-up period (first 6 months), as were white cell count and serum creatinine, while haematocrit was lower. Plasma fibrinogen values correlated positively with white cell count, and negatively with haematocrit; other cardiovascular prognostic factors did not differ. Only plasma fibrinogen predicted survival independently in multivariate age-corrected Cox regression analysis. Relative risk of death doubled for each standard deviation above the mean and increased with each tertile increase in fibrinogen. CONCLUSIONS: Fibrinogen predicted death in these elderly arteriopaths with critical limb ischaemia, particularly those who died in the first months following critical ischaemia. Inflammatory stimuli secondary to severely defective tissue oxygenation and possibly sepsis and necrosis, might have stimulated fibrinogen, an acute-phase reactant, thereby compromising organ perfusion through increased blood viscosity and/or promoting thrombosis.