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Biomedical subjects

R A Wilkins

Publications and source records attributed to R A Wilkins.

At least 19 recordsLinked to original sources
PubMed1995

Long-segment (> or = 10 cm) femoropopliteal angioplasty: improved technical success and long-term patency.

PURPOSE: To assess angioplasty as a treatment for symptomatic long-segment (> or = 10 cm) femoropopliteal atherosclerotic disease. MATERIALS AND METHODS: Angioplasty performed on 44 lesions that measured 10-40 cm (mean, 24.3 cm) were assessed for technical success and 12-24-month patency. Disease severity was assessed with the Doppler ankle-brachial index (ABI) and clinical evaluation before angioplasty and at follow-up examinations 1 month and 12-24 months (mean, 18 months) later. Technical success was defined as a restoration of vessel lumen (< 30% residual stenosis) and a rise in ABI values of at least 0.2. Arterial patency (< 50% residual stenosis) was determined with color duplex sonography. RESULTS: Angioplasty was technically successful at 41 of 44 sites (93%). There was no mortality related to the procedure or emergency surgical referral. At 18-month follow-up, mean ABI values had risen from 0.53 to 0.80. Cumulative primary patency was 69%. Clinical symptoms had improved in 83% of patients. CONCLUSION: Angioplasty is useful in the treatment of long-segment femoropopliteal atherosclerotic disease.

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PubMed1994

Percutaneous aspiration thromboembolectomy: a preliminary experience.

Percutaneous aspiration thromboembolectomy (PAT) is a radiological alternative to surgical embolectomy or thrombolysis in the treatment of acute arterial thromboembolic disease. We report our experience in eight patients aged 63-83 years (mean 71 years). Indications were graft thrombosis (1) or emboli from atrial fibrillation (3), abdominal aneurysm (2) or proximal angioplasty (2). PAT was performed at 10 arterial sites; common iliac (1), profunda femoris (1), superficial femoral (2), femoro-popliteal graft (1), popliteal (2) and arteries of the trifurcation (3). PAT was used as an adjunct to thrombolysis or angioplasty in five patients and as the sole procedure in three patients. It was successful in six patients (seven sites) with mean ABI rising from 0.4 pre- to 0.8 post-procedure. Two of the failures required amputations. One of these was a completely thrombosed dacron femoro-popliteal graft with poor run-off, and the second case had a failed surgical embolectomy prior to amputation. There were no major complications, and no mortality on follow-up at 1 month. PAT is a useful adjunct to thrombolysis and balloon angioplasty in the radiological treatment of acute thromboembolic disease. In patients in whom thrombolysis is contraindicated, it offers an alternative to surgical embolectomy.

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PubMed1990

A double blind clinical study comparing the safety, tolerance and efficacy of ioversol 240 and iohexol 240 (Omnipaque 240) in ascending venography.

A randomised, double blind, parallel group study was performed comparing the efficacy, tolerance and safety of ioversol-240 and iohexol-240 (Omnipaque-240) in 50 patients undergoing venography. Adult patients of either sex, 18 years of age or older, who were referred to the Department of Radiology at Northwick Park Hospital, Harrow, England, for ascending venography were study candidates. There were 25 patients in each drug group, who were comparable in relation to age, sex, weight, height and race. The drug groups were comparable with respect to contrast volume and iodine dose administered. All film sets were rated as diagnostic and the patient groups were comparable with respect to quality of procedure. The incidence of patients reporting heat and pain as a result of the injection of contrast medium was minimal and comparable in the drug groups. Safety was assessed by monitoring vital signs (blood pressure, pulse and respiration), clinical laboratory studies and observation of adverse effects prior to and after injection of contrast medium. Vital signs remained stable in all study patients. There were no abnormal post-procedural laboratory data which were judged to have been drug related. There were no drug related adverse effects in either group. It is concluded that ioversol-240 is a safe, well-tolerated and effective contrast agent when used for venography.

Adult↗
PubMed1990

Radiological definition of a new model of portal diversion in the rat.

Diversion of portal blood away from the liver can be accomplished in the rat by two straightforward surgical procedures: subcutaneous transposition of the spleen followed later by portal vein ligation. This experimental model has great potential value in the study of liver cell transplants, porto-systemic shunts and hepatic porto-privation. Contrast medium radiology has been used to clarify and define the model further. Splenography, achieved by direct percutaneous puncture, demonstrated the developing spleno-subcutaneous vessels. Collaterals are seen as early as 3 days and appear extensive by 21 days after transposition. Almost all emanate from the convex outer surface of the spleen and course cranially and caudally in the subcutaneous tissues to drain into the subclavian and iliac veins. The appearance of these collaterals correlates well with survival after portal vein occlusion subsequent to splenic transposition. Direct portography demonstrates that, following portal vein ligation, contrast medium is diverted away from the liver into the splenic veins, through and around the spleen, before draining into the systemic circulation through spleno-subcutaneous collaterals. These radiological studies have demonstrated the changed circulatory pathways of this model of portal diversion and have confirmed that it is the splenic veins and the spleno-subcutaneous collaterals which are fundamental to its successful outcome.

Animals↗
PubMed1990

The ossification of the costal element of the seventh cervical vertebra with particular reference to cervical ribs.

During 16 years of study at Northwick Park Hospital 715 fetuses were radiographed to determine the incidence of skeletal malformations. A technique using low kV and industrial film provided higher resolution radiographs than would have been possible in live births because of dose considerations. Gestational age calculated from LMP and ultrasound findings ranged from less than 18 weeks to 42 weeks. A separate costal element of C7, the possible precursor of a cervical rib, could be identified in 63% of fetuses. Males outnumbered females 403:311 but there was no intersex difference in the presence of such rudimentary cervical ribs with 63 and 64% respectively in each group. Of the 452 cases with separate costal elements, 73% were bilateral. Of the unilateral group 60% occurred on the right and 40% on the left. There was no significant difference in the incidence between the gestational age groups from 20 weeks onwards, confirming that the disappearance of the separate element occurs predominantly after birth, 394 cases (87%) of fetuses had an otherwise normal skeleton.

Cervical Rib Syndrome↗
PubMed1990

Peripheral laser assisted angioplasty: results, complications and follow-up.

Detailed results including complications and ultimate outcome of 24 laser assisted angioplasties in 22 patients are presented. Despite the enthusiasm expressed in other published reports, we remain sceptical of the value of laser using a 1.5 mm 'hot-tip' probe for assisting angioplasty of peripheral occlusions. The tendency for this type of probe to damage the vessel wall and in so doing prohibit the use of subsequent balloon dilatation is a major problem. In this small series the long-term patency was not improved compared with conventional angioplasty. We have established the relative safety of this laser technique and further advances in probe design may lead to greater success in crossing long lesions. Long-term maintenance of patency in these diseased arteries will need further advances in technique and assessment preferably by a controlled trial.

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PubMed1989

The expansion of interventional radiology. Report of a survey conducted by the Royal College of Radiologists.

The Interventional Radiology Group of the Royal College of Radiologists sent a questionnaire to major hospitals in the United Kingdom in 1982 and 1987 in order to assess the impact of the introduction and growth of interventional procedures on patient management over the 5-year period and to consider the implications of these data for the future staffing and equipment requirements of radiology departments. In the 194 hospitals correctly completing the most recent survey, a total of 30,794 interventional procedures were performed in a 12 month period, representing an overall increase of 116% since the previous survey of 1982.

Angioplasty, Balloon↗
PubMed1989

Safety and pharmacokinetics of ioversol in healthy volunteers.

Ioversol 320, a new nonionic iodinated contrast medium, was injected intravenously into 24 healthy male volunteers using saline as a control. Physical examination, vital signs, electrocardiogram, biochemical and hematological data were recorded before and at intervals after injection. No significant changes were observed. Seventeen volunteers reported no side effects; six volunteers had mild transitory symptoms considered to be related to the contrast medium. The authors conclude that broader clinical trials can be safely conducted to determine safety and tolerability of ioversol.

Adult↗
PubMed1986

Extrarenal arterial connections of the normal renal artery.

An angiographic study in cadavers has demonstrated connections between the renal artery and remote vessels including the intercostal, testicular, and inferior mesenteric arteries in subjects with no known history of renal disease. Such communications are a potential route by which embolic material introduced into the renal artery may inadvertently reach other organs.

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PubMed1986

Peripheral vascular disease: prospective study of intraarterial digital subtraction angiography using a 9-inch intensifier.

A prospective randomized study was undertaken to evaluate the role of intraarterial digital subtraction angiography (IADSA) in the study of peripheral vascular disease. Patients underwent either conventional film-based angiography alone, digital subtraction angiography (DSA) alone, or a combined study. With a 9-inch image intensifier, DSA alone resulted in cost savings of film and contrast material but required a significantly longer examination period than the other groups and an increased iodine dose per examination. When the images were analyzed by a radiologist and a vascular surgeon, the DSA studies provided less detail in the aortoiliac region than the other techniques but had advantages in demonstrating the runoff vessels. IADSA examination should not replace conventional arteriography in patients with peripheral vascular disease but has a useful complementary role.

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