A New Technique for Superselective Catheterization of Arteries: Preshaping of a Micro-Guide Wire into a Shepherd's Hook Form

OBJECTIVE: We wanted to introduce a new technique for superselective catheterization of arteries with preshaping of a micro-guide wire into a shepherd's hook form, and this is useful for superselection of small arteries branching at an acute angle from a large parent artery for the treatment of tumors and hemorrhages. MATERIALS AND METHODS: We developed a superselective catheterization technique by using preshaping of a micro-guide wire into a shepherd's hook form. We encountered six patients in our practice for whom we failed to catheterize the small tumor-feeding arteries that branched at an acute angle from wide parent arteries during chemoembolization of hepatocellular carcinoma; the parent arteries were the right inferior phrenic artery (n = 4) and the left gastric artery (n = 1) from the celiac axis with celiac stenosis due to compression by the median arcuate ligament and the proper hepatic artery from the gastroduodenal artery (n = 1) in a patient who had celiac axis occlusion with collateral circulation via the pancreaticoduodenal arcade from the superior mesenteric artery. In these consecutive six patients, we tested the usefulness of this new technique with employing preshaping of a micro-guide wire into a shepherd's hook form for superselective catheterization of targeted vessels. RESULTS: The target arteries were successfully catheterized and satisfactory transcatheter arterial chemoembolization was performed in all six patients. There were no significant complications such as arterial dissection. CONCLUSION: We developed a technique that is effective for superselection of vessels with preshaping of micro-guide wire into a shepherd's hook form, and we successfully applied it during chemoembolization of hepatocellular carcinoma. This technique can be useful for superselection of small arteries that branch from a large parent artery at acute angles for the treatment of tumors and hemorrhages.

Complications after Endovascular Treatment

Endovascular treatment has rapidly progressed due to the improvements of the equipment and endovascular devices. Continual refinement of the technology and techniques associated with endovascular treatment has led interventionists to perform more complicated endovascular treatment. However, the numerous complications of endovascular treatment are now well recognized and described in the literature. This article reviews various complications of three main endovascular treatments: balloon angioplasty, stent or stent-graft placement, and catheter-directed thrombolysis.

Subintimal Angioplasty in the Treatment of Chronic Lower Limb Ischemia

OBJECTIVE: To present our experience with subintimal angioplasty (SA) for treatment of chronic lower limb ischemia (CLLI) and to assess its effectiveness and durability. MATERIALS AND METHODS: From April 2003 through June 2005, we treated 40 limbs in 36 patients with CLLI by SA. Balloons with or without secondary stent placement appropriate in size to the occluded arteries were used for SA of all lesions, except for iliac lesions where primary stent placement was done. The patients were followed for 1-23 months by clinical examination and color Doppler ultrasound and/or CT angiography. Technical results and outcomes were retrospectively evaluated. The presence of a steep learning curve for performance of SA was also evaluated. Primary and secondary patencies were determined using Kaplan-Meier analysis. RESULTS: Technical success was achieved in 32 (80%) of 40 limbs. There was no statistical difference between technical success rates of 75% (18/24) during the first year and 88% (14/16) thereafter. There were four complications (10%) in 40 procedures; two arterial perforations, one pseudoaneurysm at the puncture site, and one delayed hematoma at the SA site. Excluding initial technical failures, the primary patency rates at six and 12 months were 68% and 55%, respectively. Secondary patency rates at six and 12 months were 73% and 59%, respectively. CONCLUSION: Subintimal angioplasty can be accomplished with a high technical success rate. It should be attempted in patients with CLLI as an alternative to more extended surgery, or when surgical treatment is not recommended due to comorbidity or an unfavorable disease pattern.

Stent Placement for Chronic Iliac Arterial Occlusive Disease: the Results of 10 Years Experience in a Single Institution

OBJECTIVE: We wanted to retrospectively evaluate the long-term therapeutic results of iliac arterial stent placement that was done in a single institution for 10 years. MATERIALS AND METHODS: From May 1994 to April 2004, 206 patients who underwent iliac arterial stent placement (mean age; 64+/-8.8) were followed up for evaluating the long term stent patency. Combined or subsequent bypass surgery was performed in 72 patients. The follow up period ranged from one month to 120 months (mean; 31+/-25.2 months). The factors that were analyzed for their effect on the patency of stents were age, the stent type and diameter, the lesion site, lesion shape, lesion length, the Society of Cardiovascular and Interventinal Radiology criteria, the total run off scores, the Fontaine stage and the cardiovascular risk factors (diabetes mellitus, hypertension and smoking). Follow-up included angiography and/or CT angiography, color Doppler sonography and clinical evaluation with the ankle-brachial index. RESULTS: Two hundred and eighty-four stents were placed in 249 limbs of 203 patients. The technical success rate was 98% (203/206). The primary patency rates of the stents at 3, 5, 7 and 10 year were 87%, 83%, 61% and 49%, respectively. One hundred seventy-seven patients maintained the primary stent patency until the final follow up and 26 patients showed stenosis or obstruction during the follow up. Secondary intervention was performed in thirteen patients. Lesions in the external iliac artery (EIA) or lesions in both the common iliac artery (CIA) and EIA were a poor prognostic factor for stent patency. The run off score and stent diameter also showed statistically significant influence on stent patency. The overall complication rate was 6%. CONCLUSION: Iliac arterial stent placement is a safe treatment with favorable long term patency. Lesions in the EIA or lesions in both the EIA and CIA, poor run off vessels and a stent having the same or a larger diameter than 10 mm were the poor prognostic factors for long term stent patency.

Mycotic Aneurysm of Abdominal Aorta Causing the Right Renal Arterial Stenosis: Case Report

Mycotic aneurysm of the abdominal aorta is a rare disease. Despite intensive antibiotic therapy, rupture leads to a high mortality rate, so early diagnosis and treatment is very important. Rupture is the most common complication of abdominal aortic aneurysm, while renal artery stenosis is very rare. We report the radiologic findings of mycotic aneurysm of the suprarenal abdominal aorta leading to right renal artery stenosis induced by mass effect and renovascular hypertension.

Celiac Axis Stenosis: Incidence and Etiologies in Asymptomatic Individuals

OBJECTIVE: To determine the incidence and etiologies of celiac axis stenosis in asymptomatic individuals. MATERIALS AND METHODS: This prospective study involved 400 consecutive patients (male: 319, female: 81) referred to us for celiac arteriography between April and July 1999. When celiac axis branches were opacified by collateral circu-lation during superior mesenteric arteriography, the presence of celiac axis stenosis was suspected; lateral projection celiac rteriography was performed and the pressure gradient was measured. The indicators used to determine whether or not celiac axis stenosis was significant were luminal narrowing of more than 50% and a resultant pressure gradient of at least 10 mmHg. Its etiology was deter-mined on the basis of angiographic appearances and CT findings. RESULTS: Twenty-nine patients (7.3%) had celiac axis stenosis. The etiology of the condition was extrinsic compression due to the median arcuate ligament in 16 patients (55%) and atherosclerosis in three (10%), while in ten (35%) it was not determined. The incidence of celiac axis stenosis did not vary significantly according to sex, age and the presence of calcified aortic plaque representing atherosclerosis. CONCLUSION: The incidence of hemodynamically significant celiac axis stenosis in this asymptomatic Korean population was 7.3% and the most important etiology was extrinsic compression by the median arcuate ligament of the diaphragm. Atherosclerosis was only a minor cause of the condition.

Detection of Segmental Branch Renal Artery Stenosis by Doppler US: A Case Report

In stenosis of a segmental branch or among multiple renal arteries, Doppler sampling of intrarenal arteries in the upper, mid and lower poles demonstrates strikingly different waveform patterns that might otherwise be overlooked. We report a case of segmental branch renal artery stenosis in which a pulsus parvus et tardus waveform was observed in a segmental branch of a renal artery. In this case, systematic analysis of Doppler waveforms of intrarenal arteries at more than three different locations facilitated a rapid and confident diagnosis of seg-mental branch renal artery stenosis.

Percutaneous Intravascular Metallic Stent Placement in Chronic Iliac Artery Stenoses

PURPOSE: To determine the long-term patency of percutaneous intravascular metallic stent placement in patients with chronic iliac artery stenosis. MATERIALS AND METHODS: Intravascular metallic stents were placed percutaneously in 41 limbs of 38 patients with chronic iliac artery stenosis who presented with intermittent claudication in 40 limbs and gangrene in the other. Preoperative angiography showed that complete occlusion occurred in one limb, and luminal stenosis of over 50% in 34 and of less than 50% in six. The mean length of stenoses was 3.1 (range, 1 -8) cm, and in all cases the systolic pressure gradient was over 10 (range, 12 -100, mean, 43) mmHg. Stent placement was indicated by failed balloon angioplasty in 35 limbs, primary stenting in five, and restenosis after balloon angioplasty in one. Technical and clinical success were evaluated in terms of immediate results and stent patency over a period of 1 -49 (mean, 19) months (Kaplan-Meier method). RESULTS: Stent placement was successful in all cases in which residual stenosis was less than 10% and systolic pressure gradient less than 2 mmHg. One to three days after the procedure, clinical symptoms had improved in 40 limbs and ABI (n=23) had increased from 0.64 +/-0.20 to 0.92 +/-0.17. Follow-up studies demonstrated patency rates of 94.1% at 6 months, 90.7% at 1 year, 86.6% at 2 years, and 86.6% at 4 years. CONCLUSION: Our results showed that in patients with chronic iliac artery stenosis, percutaneous intravascular metallic stent placement led to patency rates which were similar over a period of between six months and four years.

A Newly Designed Nitinol Stent: Early Clinical Experience in the Treatment of Iliac Artery Stenoses and Occlusions

OBJECTIVE: To investigate the effectiveness of the newly designed Niti-S stent in the management of iliac arterial stenoses and occlusions. MATERIALS AND METHODS: Stenoses (n=25) or occlusions (n=5) in the iliac arteries of 25 patients (30 limbs) were treated. The site of the lesions was the common (n=15) or external (n=11) iliac artery, or both (n=4). Eight limbs were treated for diffuse disease, six for highly eccentric lesion, five for occlusive lesion, and 11 for failed angioplasty. RESULTS: In all patients, technical success was achieved without major complications. One death, not procedure-related, occurred within 30 days. Ankle-brachial indexes improved from 0.63 +/- 0.30 to 0.99 +/- 0.21, and ischemic symptoms showed improvement in 22 patients (88%). Fontaine classifications before stenting, namely IIa(n=3), IIb(n=16), III(n=2), and IV(n=4) improved to I(n=17), IIa(n=5), and IV(n=3). Follow-up over a 27 (mean, 19.8 +/- 8)-month period showed that cumulative patency rates were 95.8% at 1 year and 86.2% at 2 and 3 years. No significant decrease in the mean ankle-brachial index was observed. CONCLUSION: The Niti-S stent appears to be a safe and effective device for the treatment of iliac stenoses and occlusions. These preliminary results require confirmation with a larger series.

Gadolinium-Enhanced MR Angiogra p hy of Arterial Occlusive in Lower Extremity: Comparison with Conventional Digital Substraction Angiography

PURPOSE: To compare the diagnostic value of gadolinium-enhanced MR angiography with that of conventional digital substraction angiography for the evaluation of lower extremity arterial occlusive diseases. MATERIALS AND METHODS: In 26 patients with symptomatic lower extremity arterial occlusive disease, both conventional digital substraction angiography(DSA) and gadolinium-enhanced MR angiography (CE-MRA) were performed during the same week. MR angiography was performed using three-dimensional gradient-echo ac-quisition before, and two sequential acquisitions after, the administration of gadolinium(0.2 mmol/kg). In 23 patients, two separate, contiguous areas were scanned using additional doses. In three patients, only one field with a suspicious lesion was scanned. Three radiologists independantly analysed the CE-MRA and DSA find-ings of each vascular segment(20 segments per arterial tree) for the presence of obstructive lesions; the grade assigned was either mild or none (>50 %), stenotic(50 %-99 %),or occlusion(100 %). RESULTS: From among a total of 462 segments, DSA detected 99 which were significantly narrowed (stenosis, 33; occlusion, 66). Using MR angiography, 102 segments(stenosis 39; occlusion, 63)were identified, and 94 lesions (stenosis, 32; occlusion 62) were graded correctly. Seven lesions were overestimated and four were un-derestimated. For the detection of hemodynamically significant stenosis or occlusions using MR angiography, sensitivity, specificity, and diagnostic accuracy were 95%, 98%, and 98% (G=0.995, P<0.001), respectively. To prove the absence of lesions, we repeated DSA in two patients with arterial spasm due to puncture. Three occluded segments seen on DSA, which revealed intact segments on MR angiography, suggested slow distal flow after reconstitution. CONCLUSION: For the evaluation of lower extremity arterial occlusive disease, the diagnostic value of gadolini-um-enhanced MR angiography is comparable with that of digital substraction angiography. The advantages of the former are the absence of puncture-related spasm and visualization of slow distal flow.

An Experimental Study on the Optimization of Parameter Values for Magnetic Resonance Angiography using a Phantom Model of Ulcerated Stenotic Internal Carotid Artery

PURPOSE: It has been suggested that an ulceration or hemorrhage within an atheroma on a stenotic carotid artery is a clinically important cause of transient ischemic attack(TIA). In previous studies, due to its inherent signal loss by static or turbulent flow, magnetic resonance angiography(MRA) proved to be an unreliable methed for the evaluation of subtle changes of ulceration. To improve the detectability of the ulceration within atheroma, avascular phantom was filled with gadolinium solution of various concentrations during various MR sequences. MATERIALS AND METHODS: Several vascular phantoms made of elastic silicon mimicking an ulcerated stenotic internal carotid artery(ICA) were constructed, and gadolinium solution of different concentrations (1:1000 and 1:200 of Gd-DTPA) and distilled water were introduced into the vascular phantoms using a computerized pulsatile pump. To evaluate maximum intensity projection(MIP), multiple planar reconstruction(MPR) and source images, axial and coronal images of MRA with 2D-TOF(time of flight) and 3D-TOF were reviewed. Each image of various sequences was compared with plain X-ray films of each phantom filled with barium. RESULTS: On all MR suquences, the images of the phantom of the normal carotid bifurcation were superior to the images of ulcerated and stenotic phantoms. MPR and MIP were the optimal image for detecting and defining ulceration and stenosis. Better quality images were obtained when a higher concentration of Gd-DTPA was used and when the 3D-TOF technique instead of the 2D-TOF technique was applied. CONCLUSION: This study reveals that a combination of higher concentration gadolinium with MPR and MIP on 3D-TOF technique could be optimal for the evaluation of ulceration and/or stenosis at the bifurcation of the carotid artery.

Arterial Occlusive Disease of Lower Extremity: Comparison of Spiral CT Angiography with ConventionalAngiography

PURPOSE: To evaluate and compare effectiveness of single acquisition CT and conventional angiography (CA) in grading stenosis in an artery of the lower extremity . MATERIALS AND METHODS: CA and CTA were performed in 12 patients with acclusive arterial disease of the lower extremity. CA extended from the bifurcation site of the abdominal aorta to the popliteal artery, 25-30 seconds after the injection of 120-150ml contrast media by a power injector at the rate of 2.5-3ml/sec via the antecubital vein. Using SSD and MIP methods, the data was reconstructed three-dimensionally. The artery was divided into five segments and the degree of lesion was definedas normal or mild (1-49%), moderate (50-74%), or severe stenosis (75-99%), or occlusion (100%). We retrospectively evaluated and compared the effectiveness of CTA and CA in the detection of each vessel and the grading ofstenosis. RESULTS: Although 11 segments were graded by CA as occluded, only five of these were similarly graded by CTA, and the remaining six were undergraded. The ratio of consistency for grading was 88.5% (46/52) in less thanmild stenosis, and 63.6% (7/11) in moderate or severe stenosis ; if the 11 segments detected only by CTA wereexcluded, the ratio of consistency for occlusion was 100%. Overall diagnostic accuracy was 84.2% (85/101) and whenthe 11 segments were excluded, this was 88.9% (80/90). Because of the capacity of CTA to distinguish vessles with greater than 50% stenosis from those with less than mild stenosis, sensitivity of 86.0%, specificity of 93.2% and accuracy of 89.1% were recorded. If the 11 vessels detected only by CTA were excluded, sensitivity and accuracy would be 91.3% and 92.2%, respectively. CONCLUSION: For detecting and grading stenosis in an artery of the lowerextremity, single acquisition CTA is more accurate than its conventional counter part, and we believe that CTA is a useful modality in the planning and follow-up of treatment.

Diagnosis of Renal Artery Stenosis; Spiral CTA vs. IA-DSA

PURPOSE: To evaluate the accuracy of spiral CT angiography(CTA) in the demonstration of accessory or multiplerenal arteries and renal artery stenosis. MATERIALS AND METHODS: We prospectively performed CTA in 50 patients(24 males and 26 females) between nine and 77 years old (mean 39.3) in whom renovascular hypertension was suspected (n=32), or who were potential renal donors (n=18). Within two days of CTA, intraarterial digital subtraction angiography (IA-DSA) was performed. Both spiral CTA and IA-DSA images were blindly compared by two radiologists with respect to the number of accessory renal arteries and the location and severity of renal arterystenosis. The severity of renal arterial stenosis was graded with a five-point scale (grades 0-4). RESULTS: CTA demonstrated 26 of total 27 accessory renal arteries (detection rate = 96.5 %). For the diagnosis of grade 2-4stenosis (> or = 50% stenosis) (n=40 of a total of 127 renal arteries), the sensitivity, specificity, and accuracy of CTA were 90%, 96.5%, and 94.5%, respectively. For the detection of grade 3-4 stenoses (> or = 75% stenosis) (n=33), the sensitivity, specificity, and accuracy of CTA were 87.9%, 98.9%, and 96.1%, respectively. For the detection ofgrade 3-4 stenoses in the main renal artery (n=27), the sensitivity, specificity, and accuracy of CTA were 96.3%,100%, and 99.0%, respectively. CONCLUSION: Spiral CTA is a reliable and accurate screening modality for the evaluation of renal artery in patients suspected to be suffering from renovascular hypertension, or who arepotential renal donors.