Feasibility study of computational occupational dosimetry: evaluating a proof-of-concept in an endovascular and interventional cardiology setting

Individual monitoring of radiation workers is essential to ensure compliance with legal dose limits and to ensure that doses are As Low As Reasonably Achievable. However, large uncertainties still exist in personal dosimetry and there are issues with compliance and incorrect wearing of dosimeters. The objective of the PODIUM (Personal Online Dosimetry Using Computational Methods) project was to improve personal dosimetry by an innovative approach: the development of an online dosimetry application based on computer simulations without the use of physical dosimeters. Occupational doses were calculated based on the use of camera tracking devices, flexible individualised phantoms and data from the radiation source. When combined with fast Monte Carlo simulation codes, the aim was to perform personal dosimetry in real-time. A key component of the PODIUM project was to assess and validate the methodology in interventional radiology workplaces where improvements in dosimetry are needed. This paper describes the feasibility of implementing the PODIUM approach in a clinical setting. Validation was carried out using dosimeters worn by Vascular Surgeons and Interventional Cardiologists during patient procedures at a hospital in Ireland. Our preliminary results from this feasibility study show acceptable differences of the order of 40% between calculated and measured staff doses, in terms of the personal dose equivalent quantity H_p(10), however there is a greater deviation for more complex cases and improvements are needed. The challenges of using the system in busy interventional rooms have informed the future needs and applicability of PODIUM. The availability of an online personal dosimetry application has the potential to overcome problems that arise from the use of current dosimeters. In addition, it should increase awareness of radiation protection among staff. Some limitations remain and a second phase of development would be required to bring the PODIUM method into operation in a hospital setting. However, an early prototype system has been tested in a clinical setting and the results from this two-year proof-of-concept PODIUM project are very promising for future development.

Explant of aortic stent grafts following endovascular aneurysm repair

Background

Failure of endovascular aneurysm repair may require explant of the stent graft in a subset of patients. We sought to assess outcomes in a cohort of patients undergoing explant of endovascular aneurysm repair in both emergency and elective settings.

Methods

Patients undergoing explant of endovascular aneurysm repair were identified from a prospectively maintained database, with additional information obtained through retrospective analysis of medical records.

Results

Over a 21-year period, 1997–2018 (May), there were 597 endovascular aneurysm repair procedures performed in our institution for abdominal aortic aneurysm. There were 19 endovascular aneurysm repair explants; five of these were referrals from other vascular centres. The median age was 73 years (range 46–81). The median length of time from insertion to explant was 39.2 months (range 0–153). Indications for elective explant were type Ia endoleak (n = 4), type 1b endoleak (n = 1), type II endoleak with increasing sac size (n = 1), type I/III endoleak (n = 1), type IV endoleak (n = 1), and increasing sac size without evident endoleak (type V, n = 2). The remaining nine cases were emergency procedures, with four patients presenting with rupture post endovascular aneurysm repair, four patients presenting with acute stent thrombosis, of which one also had a type 1a endoleak and one aorto-enteric fistula. There were no mortalities in the elective group and three mortalities in the emergency group (0 vs 33.3%, p = 0.087). Overall 30-day mortality was 15.8%

Conclusion

Explant of aortic stent grafts can be associated with high mortality and morbidity rates, especially in the emergent setting. Patient and device selection and post-operative surveillance remain vitally important to optimise outcomes post endovascular aneurysm repair.

Emergency endovascular management of acute thoracic aortic pathology A safe and feasible option

Endovascular repair has revolutionised the emergency treatment of thoracic aortic disease. We report our 10 year experience using this treatment in emergency cases. A prospectively maintained vascular database was analysed. Patients' medical records and CT images stored on the hospital PACS system were also reviewed. Statistical analysis was done using IBM SPSS V21. There were a total of 59 thoracic aortic stenting procedures of which 33 (60% males with a mean age of 58 yrs) were performed for emergency thoracic pathologies: traumatic transection (n = 10), ruptured aneurysm (n = 6), non-traumatic dissection (n = 8) and penetrating aortic ulcer (n = 9). All patients had self-expanding endografts implanted. Two patients required debranching procedures before the endovascular treatment. Thirty-day mortality was 12.1% (4/33). 70% of patients received a single device. There were 7 procedure related complications, 6 requiring re-intervention: thoracotomy and drainage in 2 patients, proximal graft extension in 2, open drainage of groin haematoma in 1 and open repair of a common femoral artery pseudo-aneurysm in one patient. In total 23 patients were transferred from 11 centres nationwide. There were no mortalities or other complications related to patient transfer from peripheral centres. Although acute thoracic aortic pathology is life threatening, appropriate blood pressure management and treatment of associated injuries can result in favourable outcomes. Endovascular repair is a safe and effective treatment option which enables patients to be treated with reduced morbidity and mortality. Transfer of patients with acute pathology to a tertiary centre can safely be performed.

Evolution of Carotid Surgical Practice in the last Decade

Stroke units provide immediate care and appropriate intervention in the evolving stroke. The aims of this study were to review the practice of carotid endarterectomy (CEA) before and after the establishment of a Stroke Unit in St. James's Hospital. Prior to the introduction of the Stroke Unit, 263 CEA's were performed over a five-year period. 139/263 (53%) of these were for symptomatic disease. 229 were performed in the five years since. 179/229 (78%) of these were for symptomatic disease. The 30-day stroke and death rates were < 2% before the introduction of the Stroke Unit, and have remained unchanged. Since the introduction of the Stroke Unit, there has been a slight decrease in the overall number of CEA's performed with a 25% increase in the proportion of endarterectomies performed for symptomatic disease. Despite the reduction in surgery for asymptomatic disease the overall 30-day stroke and death rate remains excellent at 2/229 (2%).

Fenestrated endovascular repair of complex aortic aneurysms

BACKGROUND

Fenestrated endovascular aneurysm repair (FEVAR) provides an endovascular solution for patients with large abdominal aortic aneurysms and challenging neck anatomy in addition to repair of endoleaks and pseudoaneurysms. This article reports the midterm outcomes of FEVAR from a single-tertiary referral centre in Ireland.

METHODS

From 2006 to 2012, nine consecutive asymptomatic patients with neck anatomy unfavourable for standard EVAR underwent endovascular repair with a customised fenestrated Zenith stent graft. An additional three patients had fenestrated grafts for repair of pseudoaneurysms (n = 2) following open AAA repair and a type I endoleak (n = 1). All patients were prospectively enrolled in a computerised database. Outcomes including mortality, morbidity, renal function, target vessel patency, endoleak and reintervention were analysed.

FINDINGS

The mean age and aneurysm size in the primary repair group were 74 years (65-84 years) and 6 cm (5-8.3 cm), respectively, and in the secondary repair group, the mean age was 66 years (61-75 years). No procedures required open conversion, and no visceral arteries were lost. On completion angiography, two patients in group 1 had a type I endoleak and one had a type III endoleak. There were no endoleaks in the secondary repair group. Follow-up ranged from 30 days to 6 years. There was one death within 30 days (8 %) and two deaths at 3 years from non-aneurysm-related causes. Six patients required secondary interventions. Three patients had a transient post-operative creatinine rise of >30 %.

CONCLUSION

Our study supports FEVAR as a feasible and effective therapy in the management of patients with complex aortic aneurysms.

Endovascular repair of thoracoabdominal aortic aneurysm (TAAA): early experience

BACKGROUND

Repair of thoracoabdominal aortic aneurysms (TAAA) represents a considerable technical challenge. Since its first description in 1955, open repair of TAAA has been considered the gold standard of repair. Despite improvements in surgical techniques, spinal cord protection and post-operative critical care support, patients who undergo open repair are faced with a mortality rate of 5-35 %. We report the first Irish experience of endovascular management of TAAAs.

RESULTS

To date five patients have undergone endovascular repair; four had hybrid repair and one a fenestrated graft. The mean age of the patients was 66.8 ± 3.4 and the mean aneurysm diameter was 6.74 ± 0.6 cm. All patients were ASA III. Two-stage hybrid repair was associated with an increased risk of complications, prolonged intensive care unit and overall hospital stay. One patient died in the perioperative period due to rupture of their aneurysm between the two stages of their hybrid repair.

CONCLUSION

The role of endovascular techniques in the treatment of TAAA continues to evolve. Hybrid and complete endovascular repairs do not replace conventional repair, but provide an alternative for high-risk patients who might otherwise be denied treatment.

Time to audit

INTRODUCTION

Public and political pressures are increasing on doctors and in particular surgeons to demonstrate competence assurance. While surgical audit is an integral part of surgical practice, its implementation and delivery at a national level in Ireland is poorly developed. Limits to successful audit systems relate to lack of funding and administrative support. In Wexford General Hospital, we have a comprehensive audit system which is based on the Lothian Surgical Audit system.

MATERIALS AND METHODS

We wished to analyse the amount of time required by the Consultant, NCHDs and clerical staff on one surgical team to run a successful audit system. Data were collected over a calendar month. This included time spent coding and typing endoscopy procedures, coding and typing operative procedures, and typing and signing discharge letters.

RESULTS

The total amount of time spent to run the audit system for one Consultant surgeon for one calendar month was 5,168 min or 86.1 h. Greater than 50% of this time related to work performed by administrative staff. Only the intern and administrative staff spent more than 5% of their working week attending to work related to the audit.

CONCLUSIONS

An integrated comprehensive audit system requires a very little time input by Consultant surgeons. Greater than 90% of the workload in running the audit was performed by the junior house doctors and administrative staff. The main financial implications for national audit implementation would relate to software and administrative staff recruitment. Implementation of the European Working Time Directive in Ireland may limit the time available for NCHD's to participate in clinical audit.

Routine staging radiology is not needed for all breast cancer patients

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Background: Early stage breast carcinoma is unlikely to have undergone metastatic spread at the time of presentation. The utility of routine staging liver ultrasound (LUS) and bone scan (BS) in early stage disease is unclear. We postulate that early stage breast cancer patients do not need routine radiological staging. Methods: We studied 200 patients with a diagnosis of invasive breast carcinoma. 100 with symptomatic breast cancer (SBC) and 100 with screen detected (SD). Patients’ histology, tumour markers (CEA, CA 15.3), hormone receptor status, CXR, LUS and BS results were reviewed. Results: All patients underwent curative surgery for early stage invasive breast cancer. 3 patients had liver metastases diagnosed by LUS. Two of these patients were from the SBC and one from SD (grade ≥2, mean tumour size 2.2 cm). 4 patients had bony metastases diagnosed by BS. Three of these were from the SBC and one from SD (grade ≥2, mean tumour size 3.2 cm.). No patients with low-grade T1 tumours had signs of metastasis on BS or US. Conclusions: The incidence of metastatic disease is very low in newly diagnosed early stage breast carcinoma. Our results suggest that patients with low-grade T1 tumours do not need staging BS or US.

No significant financial relationships to disclose.

[Cavernous hemangioma of the optic papilla: clinical and echographic findings]

BACKGROUND

Cavernous hemangiomas of the optic nerve head are rare, but their clinical features are typical. Further examinations, like fluorescein angiography and echography are necessary for a diagnostic work up.

METHODS

In June 1994 we observed a case of a cavernous hemangioma of the optic nerve head. Ophthalmological, fluoresceinangiographical and echographical examinations were done.

RESULTS

A 17-year-old woman is presented. The tumor was unilateral, only involving the optic nerve head. During a follow up period of 18 months the tumor remained unchanged.

CONCLUSION

In this patient, as in others before, ophthalmoscopical findings are characteristic for a cavernous hemangioma. Fluorescein angiography and especially the standardized echography establish the diagnosis and are helpful for accurate follow up examinations. Usually treatment of cavernous hemangiomas is unnecessary, they remain stable and usually do not cause complications. When vitreous hemorrhage occurs, vitrectomy may be indicated.

Envelope V3 region sequences of Cuban HIV-1 isolates

The origin of HIV-1 species, responsible for the AIDS epidemic in Cuba, is a subject that has been intensely debated. This study represents an initial attempt to shed light on this issue, through sequence analysis of the V3 regions of viruses isolated from 15 Cuban subjects. We now report that these viruses fall within three distinct, well-recognized groupings. These findings suggest that viruses of different sources are responsible for the HIV/AIDS epidemic in Cuba.