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ABSTRACT: Purpose: To assess selected balloon-expandable and self-expanding stents for radial force, flexibility, radio-opacity, and trackability,
and to relate these physical characteristics to potential indications for placement.
Methods: Force-strain curves were plotted for each stent and the force required to produce 50% luminal narrowing was recorded. The
ability of the stent to show elastic recoil following deformation was also noted. Flexibility was measured by bending the
stents against a force transducer and recording the force required per degree of flexion. Radio-opacity was measured by comparing
each stent against a standard aluminum step wedge. Trackability was measured by testing the ability of the stent on its delivery
system to track over angles of 90° and 60°.
Results: The balloon-expandable stents showed greater radial strength and radio-opacity but, apart from the AVE Iliac Bridge stent,
showed poorer flexibility and trackability. The self-expanding stents showed less radial force but were able to re-expand
following deformity. They were generally more flexible and had better trackability but lower radio-opacity.
Conclusion: There is no stent which exhibits all the ideal properties required and therefore the interventionist will need to keep a
range of stents available if all lesions are to be addressed.
CardioVascular and Interventional Radiology 04/2012; 23(1):47-54. · 2.09 Impact Factor
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CardioVascular and Interventional Radiology 02/2011; 34(2):252-3. · 2.09 Impact Factor
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BMJ (Clinical research ed.). 06/2008; 336(7655):1205.
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ABSTRACT: Three patients with life-threatening variceal hemorrhage secondary to portal vein (PV) thrombosis underwent endovascular treatment via the transsplenic route. The indications, techniques, and early outcomes are described. Each patient had successful portal/splenic vein recanalization with or without transjugular intrahepatic portosystemic shunt (TIPS) creation and variceal embolization with conventional catheter and wire techniques. The transsplenic approach is a useful addition to the interventional armamentarium that can be used in cases refractory to endoscopic management and unsuitable for surgical shunt procedures or conventional TIPS procedures. Longer-term follow-up will be needed to establish the durability of these procedures.
Journal of Vascular and Interventional Radiology 01/2008; 18(12):1571-5. · 2.08 Impact Factor
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Anthony A. Nicholson
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ABSTRACT: There is a large body of evidence supporting the safety and efficacy of the endovascular treatment of iliac arterial lesions
under the appropriate clinical circumstances. Although debate continues, it seems a reasonable strategy to perform angioplasty
for iliac stenosis, employing stents where angioplasty alone has failed. Iliac occlusions, however, should be managed by primary
stent insertion to avoid the high risk of distal embolisation. The results of iliac artery angioplasty or stenting are comparable
to those of surgery, and despite the TASC recommendations, a majority of surgeons and interventional radiologists seem to
favour the endovascular option wherever possible. Serious complications are relatively uncommon, but procedures should always
be performed with very careful technique, including maintaining the guidewire positioned across the lesion until a satisfactory
result has been confirmed. This allows the management of any complication endovascularly, meaning that it should only rarely
be necessary to resort to surgery.
12/2006: pages 29-39;
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ABSTRACT: To describe a 10-year experience of endovascular and percutaneous treatment of aneurysms and pseudoaneurysms complicating pancreatitis, and to analyze this experience and propose a classification based on computed tomography (CT) and angiographic findings that has therapeutic implications. This may reduce the rate of recurrent bleeding after surgery or endovascular treatment.
Twenty-three patients with aneurysms or pseudoaneurysms associated with acute pancreatitis were treated by endovascular or percutaneous methods. All underwent CT and angiography. The early development of a simple classification based on the CT and angiographic findings was used to guide treatment decisions. In accordance with this classification, 19 patients were treated by primary coil embolization and four were treated by primary percutaneous thrombin injection.
Among the 19 patients treated by primary coil embolization, there were two early recurrences of the pseudoaneurysm. All four patients treated by percutaneous thrombin injection exhibited late recurrences and were successfully treated by percutaneous thrombin injections. Twenty-one patients (91.3%) were alive at 6 months.
Endovascular and percutaneous treatment of aneurysms and pseudoaneurysms complicating pancreatitis is safe and effective and is associated with good outcomes, but careful follow-up is necessary. The decision of which treatment option is most appropriate can be made in accordance with a classification based on CT and angiographic appearance.
Journal of Vascular and Interventional Radiology 09/2006; 17(8):1279-85. · 2.08 Impact Factor
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ABSTRACT: This study was designed to determine whether routine follow-up by magnetic resonance imaging improves the detection of resectable liver metastases from colorectal cancer and patients' survival.
Patients who underwent curative surgery for colorectal cancer were included in a program of liver surveillance by routine magnetic resonance imaging, in addition to the standard follow-up protocol consisting of clinical examination and biochemical tests. The median follow-up was 41 (interquartile range, 30-53) months, with a median magnetic resonance imaging surveillance period of 20 (interquartile range, 12-27) months. Cases were analyzed for mode of diagnosis, resectability, and overall survival.
Liver metastases were found in 37 (13 percent) of 293 patients studied. Magnetic resonance imaging diagnosed hepatic metastases with 84 percent sensitivity and 90 percent specificity. In 28 (76 percent) patients, carcinoembryonic antigen and/or liver function tests were abnormally elevated and 5 patients (14 percent) were symptomatic. Hepatic resection was possible in only nine patients (24 percent). Magnetic resonance imaging detected all resectable cases, whereas traditional follow-up would have missed three (33 percent) cases suitable for surgery.
Although magnetic resonance imaging surveillance increased the number of patients suitable for liver resection by 50 percent, these represented only 1 percent of the patients included in the study. Whether these results are enough to justify the allocation of expensive resources is controversial.
Diseases of the Colon & Rectum 07/2006; 49(6):810-5. · 3.13 Impact Factor
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ABSTRACT: To determine if routine follow-up by magnetic resonance imaging (MRI) improves the detection of resectable local recurrences from colorectal cancer.
Surgical treatment offers the best prospect of survival for patients with recurrent colorectal cancer. Unfortunately, most cases are often diagnosed at an unresectable stage when traditional follow-up methods are used. The impact of MRI surveillance on the early diagnosis of local recurrences has yet to be ascertained.
Patients who underwent curative surgery for rectal and left-sided colon tumors were included in a program of pelvic surveillance by routine MRI, in addition to the standard follow-up protocol. Cases were then analyzed for mode of diagnosis, resectability, and overall survival.
Pelvic recurrence was found in 30 (13%) of the 226 patients studied. MRI detected 26 of 30 (87%) and missed 4 of 30 (13%) cases with local recurrence. Of the latter, 3 were anastomotic recurrences. In 28 (14%) patients, local recurrence was suspected by an initial MR scan but cleared by subsequent MRI or CT-guided biopsy. Recurrent pelvic cancer was diagnosed by MRI with 87% sensitivity and 86% specificity. In 19 (63%) cases, CEA was abnormally elevated, and 9 patients (30%) were symptomatic. Surgical resection was possible in only 6 patients (20%). There was no difference between MRI and conventional follow-up tests in their ability to detect cases suitable for surgery.
Pelvic surveillance by MRI is not justified as part of the routine follow-up after a curative resection for colorectal cancer and should be reserved for selectively imaging patients with clinical, colonoscopic, and/or biochemical suspicion of recurrent disease.
Annals of Surgery 04/2006; 243(3):348-52. · 7.49 Impact Factor
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Anthony A Nicholson
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ABSTRACT: It's been 30 years since an endovascular technique to control traumatic hemorrhage was first described. Despite major technical advances in both diagnostic and therapeutic technology, and a great deal of experience since then, endovascular techniques are rarely considered as part of frontline management for vascular trauma. This review considers the literature and calls for better planning and implementation of diagnostic and image-guided therapeutic facilities. Endovascular techniques should be an essential part of vascular trauma management along with endovascular specialists, partners in trauma teams.
CardioVascular and Interventional Radiology 02/2004; 27(2):105-20. · 2.09 Impact Factor
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ABSTRACT: This chapter deals with two distinct subjects, the first being the role of diagnostic imaging and the second being the treatment of vascular insufficiency of the foot resulting from diabetes. The first section covers the topics of diabetic osteopathy and neuro-arthropathy and also infection. The use of plain x-ray films is shown and examples of the bony changes seen in the diabetic foot are illustrated. The role of magnetic resonance imaging is described and there are examples of its use in the person with the diabetic foot. The second section deals with the investigation of vascular disease in the diabetic patient using duplex ultrasound, angiography and MRI. This section continues illustrating the role of endovascular procedures in the treatment of patients with diabetic vascular disease. The section covers the use of balloon angioplasty and endovascular stent insertion. There is also a section on the use of thrombolysis in the acutely ischaemic limb.
01/2002: pages 193 - 213; , ISBN: 9780470846391
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ABSTRACT: Purpose: To assess long-term outcomes following percutaneous transluminal angioplasty (PTA) of congenital aortic coarctation in adults.
Methods: Seventeen patients underwent PTA for symptomatic adult coarctation of the aorta. Sixteen patients, with a mean age of 28
years (range 15–60 years), were reviewed at a mean interval after angioplasty of 7.3 years (range 1.5–11 years). Assessment
included magnetic resonance imaging (MRI), Doppler echocardiography, and clinical examination. Current clinical measurements
were compared with pre- and immediate post-angioplasty measurements.
Results: At follow-up 16 patients were alive and well. The patient not included in follow-up had undergone surgical repair and excision
of the coarctation segment following PTA. Mean brachial systolic blood pressure for the group decreased from 174 mmHg before
angioplasty to 130 mmHg at follow-up (p = 0.0001). The mean gradient had fallen significantly from 50.9 to 17.8 at follow-up (p = 0.001). The average number of antihypertensive drugs required per patient decreased from 0.56 to 0.31 (p = 0.234). No significant residual stenoses or restenoses were seen at MRI. Small but clinically insignificant residual pressure gradients
were recorded in all patients using Doppler echocardiography. Complications included one transient ischemic attack at 5 days,
one external iliac dissection requiring stent insertion, and a further patient who developed a false aneurysm close to the
coarctation site at 12 months which subsequently required surgical excision.
Conclusion: PTA of adult coarctation is safe and effective in the long term. Although primary stenting has recently been advocated in
the treatment of this condition, our results suggest that PTA remains the treatment of choice.
CardioVascular and Interventional Radiology 08/2000; 23(5):364-367. · 2.09 Impact Factor
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ABSTRACT: Four patients, aged 54–84 years, presenting with life-threatening rectal bleeding from the superior hemorrhoidal artery,
underwent percutaneous fibered platinum coil embolization via coaxial catheters. Pre-procedure sigmoidoscopy had failed to
identify the source of hemorrhage, because the rectum was filled with fresh blood. Embolization was technically and clinically
successful in all four patients. Subsequent sigmoidoscopy confirmed the diagnoses in three patients as a solitary rectal ulcer,
iatrogenic traumatic ulceration following manual evacuation, and a rectal Dieulafoy's lesion. The other case was angiographically
seen to be due to a rectal angiodysplasia. Embolization is an effective procedure in life-threatening superior hemorrhoidal
arterial bleeding when endoscopic treatment fails, and should be preferred to rectosigmoid resection.
CardioVascular and Interventional Radiology 01/1999; 22(2):143-146. · 2.09 Impact Factor
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ABSTRACT: Purpose: To assess the feasibility and efficacy of directional atherectomy in the treatment of iliac stent stenosis or occlusion and
to evaluate the histologic composition of excised atherectomy specimens.
Methods: Directional atherectomy of six occluded and 10 severely stenosed iliac stents was undertaken in 12 patients at a mean interval
of 28 months (range 3–69 months) after stent insertion for occlusive aortoiliac disease. In cases of stent occlusion, atherectomy
was preceded by low-dose thrombolysis. In all patients stent clearance with return of femoral pulses was achieved within 24
hr and there were no significant complications. All excised specimens were sent for histologic examination.
Results: Eleven patients (92%) remain symptom free with unlimited walking distance at a mean follow-up interval of 11.5 months (range
3–31 months) after treatment. Histologic examination revealed typical myointimal hyperplasia at three excision sites, intimal
fibrosis at three sites, atheroma at four sites and organized thrombus at six sites.
Conclusion: Atherectomy offers an effective treatment in iliac stent occlusion and restenosis with no significant adverse effects. Debulking
of these lesions seems to offer a more logical approach than simple balloon angioplasty. Clinical and duplex follow-up confirms
satisfactory outcome within the first year but longer-term results are not yet known. The histologic data obtained demonstrate
that stent restenosis and occlusion are likely to be multifactorial, and challenge the assumption that myointimal hyperplasia
is the sole cause of iliac stent occlusion.
CardioVascular and Interventional Radiology 04/1998; 21(6):475-480. · 2.09 Impact Factor
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ABSTRACT: The case of a 30-year-old woman with a post-traumatic pseudoaneurysm of the superior mesenteric artery and associated celiac axis occlusion is presented. The patient was successfully treated with celiac artery recanalization and placement of a covered stent within the superior mesenteric artery. Follow-up at 3, 6, and 12 months and 3 years demonstrated patency of the covered stent and continued exclusion of the aneurysm. Although the long-term success of this procedure is unknown this management option should be considered where facilities are available, to reduce the increased morbidity associated with open surgical procedure.
CardioVascular and Interventional Radiology 29(5):886-9. · 2.09 Impact Factor
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ABSTRACT: The Amplatzer Vascular Plug (AVP) is a self-expanding nitinol wire mesh vascular embolization device derived from the Amplatz septal occluder. We assessed the results of vascular embolization obtained using the AVP.
A retrospective review was carried out of 23 consecutive cases of vascular embolization using the AVP in a variety of different clinical settings. The AVP was chosen to have a diameter approximately 30-50% greater than the target vessel. The device was delivered via an appropriately sized guide catheter and was released when satisfactorily positioned. Additional embolic agents were used in some cases.
All target vessels were successfully occluded with no device malpositioning or malfunction. In 14 (61%) patients the AVP was the sole embolic material. In the remaining patients additional agents were used, particularly in preoperative embolization of highly vascular renal tumors. The AVP does not cause instantaneous thrombosis and in high-flow situations thrombosis typically takes up to 15 min.
The AVP is a safe, effective embolization device that provides a useful adjunct to the therapeutic armamentarium. It is particularly suited to the treatment of short high-flow vessels where coil migration and catheter dislodgment might occur. In the majority of cases no additional embolic agents are necessary but it may take up to 15 min for complete thrombosis to occur.
CardioVascular and Interventional Radiology 30(4):650-4. · 2.09 Impact Factor
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ABSTRACT: PurposeThe results of treating malignant superior vena cava obstruction by means of percutaneous self-expanding stent insertion or by means of radiation therapy were compared.Patients and MethodsSeventy-six patients with malignant superior vena cava obstruction who were treated by stent insertion were studied prospectively and 25 patients who were treated by radiation therapy were studied retrospectively. A superior vena cava obstruction score was devised to measure treatment effectiveness. Speed of symptom relief and complications were recorded. End points in the study were recurrent obstruction or death. Asymptomatic survival times were compared by log rank and Mann Whitney tests of significance, as well as Kaplan-Meier analysis. A subgroup of 26 patients who were treated by stent placement only were compared with the radiation therapy group and analyzed separately.ResultsThere were seven complications in the overall stent group, one in the stent-only group, and 25 in the radiation therapy group. Stent insertion provided faster relief of symptoms and significantly greater improvement in the superior vena cava obstruction score than radiation therapy (P < .001, Mann-Whitney U test). A Kaplan-Meier analysis of asymptomatic survival demonstrated that significantly fewer patients in the overall and stent-only groups developed recurrent symptoms (P = .0005 and .001, respectively, log rank test).ConclusionThis study suggests that percutaneous stent insertion in malignant superior vena cava obstruction fulfills the requirements of a palliative procedure significantly better than radiation therapy and that it should be the procedure of first choice.
Journal of Vascular and Interventional Radiology.
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ABSTRACT: PurposeA retrospective evaluation of outcomes in patients with chronic iliac occlusions treated with insertion of metallic endovascular stents, without previous thrombolysis, on an intention-to-treat basis.Materials and MethodsSeventy-two patients with chronic iliac occlusion underwent attempted stent placement from either the ipsilateral or contralateral femoral artery. There were 49 men and 23 women. Mean age was 63.1 years (range, 39–88 years). A total of 89 stents were deployed in 67 patients. Follow-up was from 24 to 69 months (mean, 37.5 months).ResultsStents were successfully deployed in 67 patients (93%), with two early failures, giving a primary success rate of 90%. There were five significant and four insignificant procedural complications. There were four late failures (all within the first year) and four non–stent-related deaths.ConclusionEndovascular stent placement offers an alternative to surgery in the treatment of chronic iliac occlusions.
Journal of Vascular and Interventional Radiology.
