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Biomedical subjects

C O McDonnell

Publications and source records attributed to C O McDonnell.

14 recordsLinked to original sources
PubMed2006

Value of diffusion-weighted MRI during carotid angioplasty and stenting.

INTRODUCTION: The incidence of neurological injury following carotid angioplasty and stenting is of great interest to those advocating it as an alternative to endarterectomy in the management of critical carotid stenosis. A significant inter-observer variation exists in determining the presence or absence of a neurological deficit following the procedure objective imaging would be advantageous. In this study, we sought to assess diffusion weighted MRI as a diagnostic tool in evaluating the incidence of neurological injury following carotid angioplasty and stenting (CAS). PATIENTS AND METHODS: The first 110 cases of CAS in our unit were included in this series. The procedure was abandoned in three patients. Patients underwent intracranial and extracranial MR angiography, together with diffusion-weighted MRI (DWI) prior to and following CAS and had a formal neurological assessment in the intensive care unit after the procedure. RESULTS: One hundred and ten Procedures were attempted in 98 patients. Twenty-eight percent were asymptomatic. Following CAS, 7.2% of patients had a positive neurological exam (two major strokes with one fatality) and 21% had positive DWI scans, equating to a sensitivity of 86% and a specificity of 85% for DWI in detecting cerebral infarction following CAS. The positive predictive value of the test was 0.3 and negative predictive value 0.99. The major stroke and death rate was 1.8%. While the use of a cerebral protection device appeared to significantly reduce the incidence of cerebral infarction (5% vs. 25%, p = 0.031) this may be a reflection of the learning curve encountered during the study. CONCLUSION: The incidence of subclinical DWI detected neurological injury was significantly higher than clinical neurological deficit following CAS. Conventional methods of neurological assessment of patients undergoing CAS may be too crude to detect subtle changes and more sensitive tests of cerebral function are required to establish whether these subclinical lesions are relevant.

Aged↗
PubMed2004

Carotid artery angioplasty for restenosis following endarterectomy.

INTRODUCTION: The higher complication rate associated with the surgical treatment of restenosis following carotid endarterectomy (CEA) has led several authors to advocate angioplasty as the treatment of choice in the management of restenosis. We describe our experience with internal carotid artery angioplasty for post-endarterectomy restenosis over 7 years. PATIENTS AND METHODS: From January 1994 to April 2001, all patients with a >90% restenosis following CEA were considered for angioplasty. Thirty angioplasties were carried out in 25 patients, 80% (24/30), for asymptomatic recurrent stenosis. There was no difference between those who had intervention for recurrent stenosis (n=31) and those who did not (n=545) in age, sex, smoking status or incidence of diabetes or hypertension. A significantly greater number of patients who underwent angioplasty were hypercholesterolaemic (p<0.05, Chi-squared test). RESULTS: Mean time from surgery to angioplasty was 13 months (range 1-23). Angioplasty was technically successful in 29 cases (97%). Three patients (10%) experienced transient neurological symptoms during the procedure. There were no strokes. Ninety-six percent (28/29) of patients were followed up with duplex scanning. Mean follow-up was 20 months (range 2-48). Three patients developed a greater than 90% restenosis. CONCLUSION: Angioplasty is an acceptable alternative to surgery in the management of internal carotid artery restenosis following endarterectomy.

Aged↗
PubMed2004

Improvement in efficacy of chemoradiotherapy by addition of an antiangiogenic agent in a murine tumor model.

BACKGROUND: Chemoradiotherapy improves survival for some cancer patients. Methods of enhancing treatment response would further enhance survival rates. The effect of the addition of an antiangiogenic agent to a chemoradiotherapy regime has not previously been examined. MATERIALS AND METHODS: C57B16 mice were inoculated with 1 x 10(6) Lewis lung carcinoma cells into the flank and randomized to 1 of 10 treatment groups when tumor volume approached 1000 mm(3). Animals received combinations of standard doses of intraperitoneal cisplatin, 5-fluorouracil, and the antiangiogenic agent genistein, together with 10 or 20 Gy of external beam radiotherapy. Animals were sacrificed at day 6 when tumor volume, microvessel density, and serum VEGF were determined. RESULTS: Mean (SEM) tumor volume in the chemoradiotherapy group was 762 (212) mm(3) versus 565 (79) mm(3) in the chemoradiotherapy plus genistein group (P = 0.04, unpaired t-test). The addition of genistein produced a significant reduction in tumor microvessel density (P = 0.01) as well as serum VEGF levels (P < 0.05) compared to those animals receiving chemoradiation alone. CONCLUSIONS: This study provides proof of principle that chemoradiation can be enhanced by the addition of an antiangiogenic agent to the regime and suggests that further examination of such regimes is warranted.

Angiogenesis Inhibitors↗
PubMed2003

Effect of neoadjuvant chemoradiotherapy on angiogenesis in oesophageal cancer.

BACKGROUND: Vascular endothelial growth factor (VEGF) levels are raised in the serum of patients with oesophageal carcinoma. The aim of this study was to evaluate the tumour microvasculature and the role of tumour-associated macrophages in VEGF production after neoadjuvant chemoradiotherapy and surgery for oesophageal cancer. METHODS: Sections from 92 consecutively resected oesophageal tumours were stained for VEGF, von Willebrand factor and CD68. Twenty-seven patients received preoperative chemoradiation and 65 underwent surgical excision alone. The cellular source of VEGF was determined by parallel-section staining. Microvessel density and macrophage count were determined for each tumour by means of image analysis software. RESULTS: There were no significant differences between the two groups in age, sex or tumour type. Local downstaging of disease was evident in most specimens of tumours that had received preoperative chemoradiation. All tumours stained positive for VEGF, including those demonstrating a complete pathological response. Staining of parallel sections confirmed macrophages as the principal source of VEGF. Mean microvessel density was 6.4 per high-power field (h.p.f.) in tumours that received preoperative chemoradiation compared with 5.3 per h.p.f. in those treated by surgery alone (P = 0.130). A significant increase in tumour-associated macrophage infiltration was noted in tumours treated with neoadjuvant chemoradiation (22.1 per h.p.f.) compared with those treated by surgery alone (14.3 per h.p.f.) (P = 0.042). CONCLUSION: Preoperative chemoradiation had little effect on the local angiogenic profile of the tumour in patients with oesophageal cancer. Tumour-infiltrating macrophages seem to be the source of persistent VEGF production after chemoradiotherapy and might explain the raised serum levels. Addition of an antiangiogenic agent to this regimen may be worthwhile in patients with oesophageal carcinoma.

Adenocarcinoma↗
PubMed2001

Effect of multimodality therapy on circulating vascular endothelial growth factor levels in patients with oesophageal cancer.

BACKGROUND: Angiogenesis is critical for tumour growth and metastasis. The switch to the angiogenic phenotype depends on the net balance between positive and negative angiogenic factors released by the tumour. It was hypothesized that patients with oesophageal cancer would express raised serum levels of vascular endothelial growth factor (VEGF) which would return to normal values with neoadjuvant chemoradiotherapy. METHODS: Forty-four patients with oesophageal cancer who were selected for treatment with neoadjuvant chemoradiotherapy had blood samples taken before treatment, during chemoradiotherapy, before operation, on days 1, 3 and 5 after surgery, and 3 months after resection. Serum levels of VEGF were measured. Values were correlated with response to treatment. Controls were patients who were undergoing surgery for non-malignant conditions. RESULTS: Serum VEGF levels were raised in patients with oesophageal cancer compared with age-matched controls (mean 247 versus 1157 pg/ml; P < 0.01). VEGF levels were unaffected by neoadjuvant treatment but fell significantly on the first day after operation (652 versus 1057 pg/ml before operation; P < 0.05). No decrease occurred in control patients. VEGF levels had returned to preoperative levels by day 5. A similar postoperative rise in VEGF levels was seen in the control subjects (1194 pg/ml on day 5 versus 71 pg/ml before operation; P = 0.001). There was no correlation between VEGF level and response to treatment or tumour stage. VEGF levels had decreased significantly at 3 months following tumour resection (594 versus 1558 pg/ml on day 5; P = 0.03). CONCLUSION: VEGF levels are raised in patients with oesophageal cancer and are unaltered by neoadjuvant treatment, suggesting an additional source other than tumour cells for this proangiogenic agent.

Adenocarcinoma↗
PubMed2000

Tumour micrometastases: the influence of angiogenesis.

INTRODUCTION: Many cancer patients have undetected micrometastatic disease at first presentation which ultimately progresses. Angiogenesis-the development of an independent blood supply-is a key event in the growth of metastases. Improved understanding of the influence of angiogenesis on micrometastatic growth may lead to new therapeutic intervention. METHODS: This study examines current concepts of the significance of micrometastases and the role of angiogenesis in their development and destruction. A comprehensive review of the literature on micrometastasis and angiogenesis was performed using the Medline database between 1966 and 1999. CONCLUSIONS: Advances in technology have improved our ability to diagnose metastatic disease, but micrometastases in loco-regional lymph nodes and at distant sites can only be detected by sophisticated histological techniques. While the significance of micrometastases remains controversial, there is increasing evidence that micrometastatic status provides useful prognostic information and should be part of standard staging techniques. Anti-angiogenic therapy has the potential to favourably influence management of certain cancers by manipulating a number of key events in the metastatic process.

Bone Marrow Neoplasms↗
PubMed2000

Suprarenal mycotic aneurysm exclusion using a stent with a partial autologous covering.

PURPOSE: To report a combined endovascular and open technique to manage a suprarenal mycotic aortic aneurysm using a stent-graft partially covered with a section of autologous artery. METHODS AND RESULTS: A 50-year-old was hospitalized for staphylococcal septicemia and severe back pain. A previously diagnosed 3-cm abdominal aortic aneurysm was found to have expanded 2 cm in 3 weeks. Aortography documented some periaortic thickening and 2 mycotic aneurysms, one posterior at the level of the superior mesenteric artery and the second at the aortic bifurcation. After intensive antibiotic therapy, an endovascular approach to exclude the suprarenal mycotic aneurysm was undertaken in tandem with surgical excision of the infrarenal aneurysm. The harvested right common iliac artery was used to partially cover a Palmaz stent, which was deployed under direct vision just above the renal artery ostia so that the covered portion of the stent excluded the aneurysm. A right axillofemoral bypass with a femorofemoral bypass completed the revascularization. Postoperatively, the patient developed renal failure, ischemic colitis necessitating a left hemicolectomy, and paraplegia. Although the patient is paralyzed, the aneurysm remains excluded with patent visceral vessels at 12 months following surgery. No organisms were grown from excised aortic tissue, and no signs of recurrent infection have been seen. CONCLUSIONS: Stent-graft repair may be able to lessen the invasiveness and reduce the morbidity associated with treatment of mycotic aortic aneurysms.

Aneurysm, Infected↗
PubMedDate not supplied

Laparoscopic repair of a strangulated Bochdalek hernia.

BACKGROUND: Bochdalek herniae are rare. They are usually repaired by open abdominal surgery or by a thoracic video-assisted approach. When strangulated and in a compromised patient the options are fewer. AIM: To describe a case treated by a laparoscopic approach. RESULTS: The procedure was technically difficult, but the patient recovered without recurrence. CONCLUSION: Laparoscopic repair is possible even with strangulation.

Aged↗
PubMedDate not supplied

"Is this a dagger I see before me?"--an audit of stabbings and gunshot wounds in Limerick.

BACKGROUND: According to a recent study in Cardiff, the incidence of stab wounds is 14 per 100,000 population per annum. No such figures are available for Ireland. AIM: To evaluate the incidence, type of injury, medical consequences and outcome of patients with stab or gunshot wounds presenting to the Mid-Western Regional Hospital, Limerick, over a 12 month period. METHOD: A retrospective case study of all stab and gunshot wounds presenting over a 12 month period. RESULTS: Out of 62,000 new presentations to the Accident and Emergency (A&E) department, 101 (0.16%) were stabbings, giving an incidence of 33 per 100,000 population. Twenty-six patients required surgical intervention. There were three deaths. There were 10 gunshot wounds, of which 40% required surgical intervention, with no mortalities. CONCLUSION: The incidence of stab wounds presenting to our institution is high. Although constituting a small percentage of presentations to the A&E department they result in considerable morbidity and surgical activity.

Adolescent↗
PubMedDate not supplied

Abdominal aortic aneurysm neck morphology: proposed classification system.

BACKGROUND: While aneurysm neck length, angulation and width have all been previously assessed in endovascular abdominal aortic aneurysm repair (EVAR), aneurysm neck shape has not been considered. AIMS: To analyse the influence of aneurysm neck morphology on outcome following EVAR. METHODS: Aneurysm neck morphology in 70 patients undergoing EVAR from April 2001 to May 2004 was determined using pre-operative CT scans and graft plans. Necks were classified as flared, parallel, irregular, conical, barrel or hourglass. End-points were death,Type I endoleak and graft migration. RESULTS: Forty-six per cent of necks were flared, 34% parallel, 9% irregular, 6% conical, 3% barrel and 3% hourglass. Mean follow-up was 20.2 months (range 4-35). There was one Type I endoleak and one graft migration. There were no aneurysm related deaths. CONCLUSIONS: Assessment of aneurysm neck morphology should be part of the routine preoperative workup for EVAR. A classification system of AAA necks is suggested to facilitate this.

Aortic Aneurysm, Abdominal↗
PubMedDate not supplied

Low dose intraarterial thrombolysis with tissue plasminogen activator: does it deliver as promised?

The widespread use of intraarterial thrombolytic therapy has been based on perceived benefits over operative treatment and the downgrading of the magnitude of subsequent surgery. Thirty-three patients who had thrombolysis for peripheral artery occlusion were retrospectively analyzed at St. James's Hospital from 1991 to 1997. One patient received streptokinase unsuccessfully. Five other patient's records were inadequate for analysis. Twenty-seven patient's notes were analyzed for risk, duration of occlusion, duration of treatment, dosage of tissue plasminogen activator (tPA) and conduits thrombolysed. There were 15 males and 12 females. The mean age was 62 years (range, 20-87). Fourteen were current or reformed smokers. Five were diabetic. Indications for treatment included acute graft occlusion (n=13), embolus (n=6), and primary and secondary arterial thrombosis (n=8). Duration of occlusion was less than 24 hours in seven, 1 to 7 days in ten, and more than 7 days in ten patients. Twelve (44.44%) patients had complete clot lysis, four (14.81%) had partial clearance, and 11 (40.74%) remained occluded. Eight (29.63%) had serious complications including one death. Eighteen (66.66%) patients needed further surgical intervention to maintain graft patency. Data were analyzed using the chi-square and pooled t test. No significant difference was observed in results from thrombolysis from different conduits, gender, etiology, or smoking history. Increased duration of tPA administration was associated with an increased risk of failure. Administration of total dosages greater than 60 mg was associated with a higher risk of failure. Diabetics had a poor outcome (p=0.0520). Only 44 % of patients successfully underwent lysis. A primary surgical option may be a more sensible course than lysis, given that the vast majority of patients ended up having surgery anyway.

Adult↗