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Intraluminal ultrasound guidance of transverse laser coronary atherectomy.

Catheter systems for laser atherectomy in peripheral and coronary arteries are subject to many design constraints. Ideal mechanical, laser and imaging requirements for these systems are proposed, and compared to the design features of a laser atherectomy system currently under development by Intra-Sonix. This system uses high resolution ultrasound for real-time guidance and control and is potentially capable of characterizing lesions and imaging critical structures in the coronary arteries, to guide physicians in the application of laser therapy. Precise catheter location and rotational direction can be provided continuously as the therapeutic intervention proceeds. Examples are given of the imaging modes and ultrasound images of an artery produced by the Intra-Sonix system.

Angioplasty, Balloon↗

Percutaneous transluminal atherectomy: preliminary results.

Percutaneous transluminal atherectomy with the Simpson atherectomy catheter was performed in 10 patients with 14 severe atheromatous stenoses of the femoropopliteal arteries. Removal of plaque material with restoration of vessel patency was successful in all patients without complication. Further clinical follow-up will have to determine whether the recurrence rate of stenoses will be lower with this method than with conventional balloon angioplasty.

Adult↗

Treatment of symptomatic peripheral atherosclerotic disease with a rotational atherectomy device.

Narrowings 70 to 90% in diameter in 3 iliac, 4 superficial femoral and 2 popliteal arteries were crossed and atherectomized successfully in 6 patients using the Squibb Rotablator under angiographic guidance during surgical bypass procedures on these arteries. The Rotablator consists of a 1.25 to 4.5 mm diameter oblong burr with tiny diamond blades mounted on a flexible shaft, which tracks over a spring-tip guidewire and rotates at speeds greater than 120,000 rpm. All stenoses were reduced to less than or equal to 50% of the normal luminal diameter. No significant complications occurred. Of the 6 patients having the atherectomy procedure, 5 were reevaluated by duplex Doppler measurements 1.5 to 5.5 (mean 3.5) months after atherectomy and found to be patient with only mild residual flow disturbance. Repeat follow-up by angiography after a mean of 5.2 months, however, showed only 3 (37%) of the atherectomized segments in 3 patients to still be patent. All were symptomatically improved. Of the effluent particles analyzed, 90% were less than 8 microns in size, while only 5% reached 250 microns. With improvements in technique, the largest particles were 150 to 180 microns, constituting only 1.4% of effluent debris. Samples of the effluent from 2 patients were injected in vivo into the left coronary system of 2 pigs. There were no acute hemodynamic or electrocardiographic complications or pathologic evidence of muscle necrosis or vascular thrombosis 18 to 48 hours later. These preliminary results with respect to feasibility and safety of the Rotablator are promising.

Adult↗

Cell constitution and characteristics of human atherosclerotic plaques selectively removed by percutaneous atherectomy.

The Simpson atherectomy device used for the recanalization of severely stenosed peripheral arteries is able to collect plaque material which can be further characterized. This study reports histological, immunohistochemical and transmission electron microscopic findings on advanced human primary atherosclerotic plaques of peripheral arteries percutaneously removed by a Simpson atherectomy catheter. Material from stenosing plaques consisted of dense connective tissue with abundant amounts of concentrically arranged elastic fibers and lamellae. This meshwork contained numerous cells, often arranged in clusters and oriented with their longer axis parallel to the direction of blood flow. The vast majority of these cells could be easily identified as vimentin-positive and desmin-negative smooth muscle cells containing lipid deposits in the perinuclear region and numerous glycogen particles. Monocytes/macrophages were observed only very infrequently. Plaque tissue contained a range of smooth muscle cell phenotypes. Most of the cells were of an intermediate phenotype, i.e. sparsely filled with myofilament bundles at the cell periphery and a high amount of organelles such as mitochondria, rough endoplasmic reticulum and Golgi cisterns. An intact lining of pieces of intimal tissue with endothelial cells was not observed. Two-dimensional gel electrophoresis of plaque tissue showed the presence of alpha-, beta- and gamma-actin isoforms with a clear predominance of the beta-isoform.

Arteriosclerosis↗

Percutaneous peripheral atherectomy: angiographic and clinical follow-up of 60 patients.

The Simpson atherectomy catheter was used to treat 60 patients with a total of 94 lesions comprising 63 stenoses (mean length 1.1 +/- 0.5 cm) and 31 occlusions (4.2 +/- 2.9 cm) of the superficial femoral (n = 77), popliteal (n = 8), iliac (n = 8) and anterior tibial (n = 1) arteries. The immediate angiographic success rate was 90% for both occlusions and stenoses, and clinical success was obtained in 82% of patients. The stenoses were reduced from 83 +/- 13% to 17 +/- 18% acutely and to 31 +/- 26% at 6 months; the occlusions were reduced from 100% to 9 +/- 9% initially and to 60 +/- 34% at 6 months. Angiographic restenosis was found in 24% of lesions: 23% in concentric and 11% in eccentric lesions and 47% in total occlusions. At 1 year, 72% of patients had clinically patent arteries with maintained Doppler index and walking distance. Three of four patients undergoing repeat atherectomy had a second restenosis. In summary, the procedure was found to be safe and effective in the treatment of peripheral vascular disease. It appears to be particularly beneficial in the treatment of eccentric stenoses and is not limited by the presence of calcification.

Aged↗

Coronary atherectomy. An alternative to balloon angioplasty.

To date, physicians at our hospital have performed coronary atherectomy on 15 patients. Of these patients, four needed open heart surgery. One patient needed surgery because a vessel was dissected during the procedure, and the three other patients had unsuccessful procedures. One patient died due to a cerebrovascular bleed related to the anticoagulation therapy required for the procedure. Of the remaining patients, three had no reocclusion and four had reocclusion at their six-month follow-up examinations. The remaining patients have not had a six-month follow-up examination. The restenosis rate at our institution is 25%. It is hoped that catheter-mediated atherectomy will be an effective, predictable transluminal treatment of single or multiple focal stenosis. Because of the small patient sampling and short duration follow-up, no trends have been established. A six-month follow-up with angiography will establish patency and restenosis rates.

Coronary Artery Disease↗

Percutaneous atherectomy--early experience in Sheffield.

Percutaneous transluminal angioplasty (PTA) of arterial stenoses is a well-established and relatively safe technique in the treatment of peripheral and coronary vascular disease. Recurrence, however, remains a problem. The 'atherectomy' catheter is a new device to provide lumen enlargement by the mechanical removal of atheroma. In Sheffield, 14 lesions in the femoral arteries have been treated by atherectomy, with a reduction in mean diameter stenosis from 88% to 15%. There were no complications. Follow-up ranges from 3 to 15 months, with a mean of 9 months. There has been only one recurrence. It can be used in calcified lesions and may prove to be most useful in the treatment of tough lesions. Further experience and follow-up is necessary, however, to determine whether it has any advantage over balloon dilatation.

Aged↗

Differential histopathology of primary atherosclerotic and restenotic lesions in coronary arteries and saphenous vein bypass grafts: analysis of tissue obtained from 73 patients by directional atherectomy.

Vascular tissue obtained using a directional percutaneous atherectomy device was examined microscopically. Tissue was obtained from coronary arteries without prior instrumentation (primary lesions, n = 31), aortocoronary saphenous vein bypass grafts with primary lesions (n = 8), coronary arteries with lesions developing after prior balloon angioplasty or mechanical atherectomy (restenotic lesions, n = 30) and vein bypass grafts with restenotic lesions (n = 4). Primary lesions were characterized by dense intimal fibrosis with necrotic debris (83% of intimal tissue) and foam cells typical of atherosclerosis. These lesions frequently contained cholesterol crystals (45% of coronary arteries, 50% of vein grafts) and calcium deposits (65% of coronary arteries, 38% of vein grafts). Restenotic lesions were characterized by an increased proportion of loose fibroproliferative tissue (45% of coronary artery intima, 35% of vein graft intima). Immunohistochemical stains confirmed this proliferative tissue to be primarily smooth muscle cells. Thrombus was rarely observed. Comparison of resected tissues indicated that dense fibrosis and necrosis are significantly more common in primary than in restenotic lesions (83% versus 56% of intimal tissue, p = 0.0005), whereas smooth muscle cell hyperplasia is more common in restenotic than in primary lesions (44% versus 17% of intimal tissue, p less than 0.0005). Partial-thickness resection of medial tissue or full-thickness resection of media with associated adventitial tissue occurred in 27 (56%) of 39 primary atheromatous lesions and 16 (47%) of 34 restenotic lesions; subintimal tissue obtained from primary lesions appeared identical to that obtained from restenotic lesions. These data indicate that the histopathologic characteristics of the neointimal layer of restenotic lesions differ from those of the intimal layer of primary atherosclerotic lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Constriction, Pathologic↗

Percutaneous atherectomy with the Kensey catheter: early and midterm results in femoropopliteal occlusions unsuitable for conventional angioplasty.

Forty-six femoropopliteal occlusions in 44 patients (aged 45-95 years) were recanalized with the percutaneous rotating tip atherectomy catheter completed by balloon dilatation. Thirty-one patients had tight intermittent claudication of the lower limbs, five had resting pain and 10 had skin disorders. The length of the occlusion ranged from 2 to 24 cm. Of 46 procedures, 40 (87%) were immediately successful (increase of mean Doppler systolic ankle-arm index from 0.44 to 0.89) and six (13%) were failures. In two it was impossible to pass through the lesion and in four arterial perforation occurred without any clinical consequences. Of the six failures, five occurred in calcified arteries. Five recanalizations (11%) reoccluded within 48 hours, bringing the total number of early failures to 11. Of these 11 failures, nine were treated by femoropopliteal vein bypass and two by medical treatment only. Two postoperative asymptomatic posterior tibial artery embolisms were treated medically, and one popliteal artery embolism was treated using a Fogarty catheter. At the present time, 25 of 35 primary successes had been followed for six months, and 20 for 12 months with primary patencies 18 of 25 (72%) and 14 of 20 (70%), respectively. If massively calcified lesions are excluded, femoropopliteal recanalization with the percutaneous rotary Kensey atherectomy catheter followed by balloon catheter dilatation is efficacious and reliable with an 80% primary success rate and a 70% patency rate at one year.

Aged↗

[Simpson's atherectomy of the peripheral arteries: early results and follow-up].

Over a seventeen-month period, a percutaneous transluminal removal of stenosing plaque material from leg and pelvic arteries was performed successfully and without complication in 43 patients. A complete atherectomy in the femoropopliteal vessels succeeded in 99% of cases. In the pelvic region, the primary results were much lower (58%). After six months, the angiographically checked restenosis rate was 17% for femoropopliteal vessels and 11% for iliac arteries, and the corresponding Kaplan-Meier cumulative patency rates were 73.8 and 78.7% respectively. Simpson's atherectomy is the only method of its kind that is therapeutically effective and diagnostically significant, since the removed plaque can be used for further tests.

Aged↗

[Successful directional coronary atherectomy after futile attempts at balloon dilatation].

Coronary arteriography revealed severe stenoses of the proximal part of the anterior interventricular branch with normal ventricular function in two patients (aged 42 and 38 years) with stable angina and ischaemia reaction in the exercise ECG. In the first patient it was a short spur-like 80% narrowing. But percutaneous balloon angioplasty failed to change the angiographic appearance. In the other patient there was an eccentric, apparently elastic, 90% stenosis, about 10 mm long. Here, too, balloon angioplasty had failed. Subsequently directional coronary atherectomy in both patients achieved removal of the stenosis with lasting clinical improvement. Atherectomy should be considered in similar cases after failed balloon dilatation.

Adult↗

[Percutaneous peripheral atherectomy in arterial occlusive disease. Angiographic and clinical acute and long-term results].

130 arteriosclerotic lesions--10 in the iliac, 109 in the superficial femoral, 10 in the popliteal and 1 in the anterior tibial artery--were treated by percutaneous atherectomy in 80 patients (62 men and 18 women: mean age 65 +/- 10 years). 23 of the lesions were concentric, 65 eccentric stenoses, while 42 were fully occlusive. 32 patients were in stage IIb (after Fontaine), 24 in stage IIa and 12 each in stage III or IV. Most of the stenoses were not suitable for conventional balloon dilatation because of their primary morphology. A good early angiographic result (residual stenosis less than 50%) was achieved in 94% of lesions. Mean stenosis degree was reduced from 85 +/- 12% to 12 +/- 10% (occlusions from 100% to 9 +/- 9%). The Doppler index increased from 0.6 +/- 0.18 to 0.85 +/- 0.15 (P less than 0.01). Follow-up angiography after 6 months in 104 lesions demonstrated an average stenosis degree of 33 +/- 25% (occlusions 44 +/- 28%). 26 of the 104 re-studied lesions fulfilled the criterion for re-stenosis (greater than 50%): six concentric ones and five eccentric ones, as well as 15 occlusions. These findings indicate that peripheral atherectomy can be employed with good short and long-term results even in morphologically unfavourable, markedly eccentric or calcified lesions and occlusions.

Acute Disease↗

Rotational Atherectomy in Octogenarians: Results and Follow Up.

We examined our first 390 rotational atherectomy procedures to determine success and complications rates of patients aged 80 or greater (Group I, N equals 35) as compared to those younger (Group II, N equals 355). Procedural success was achieved in 32/35 (91%) of Group I and 42/355 (96%) of Group II patients (p equals NS). Coronary artery bypass graft surgery was required in 2/35 (5.7%) of Group I and 7/355 (2%) of Group II patients. No deaths, Q wave infarctions, or perforations occurred in the elderly patients and only one of each was observed in the younger group. During clinical follow up (26 months, 3-50), 4/25 patients (16%) in the octogenarian group died. Two of the deaths were cardiac (including the only crossover to surgery). One patient who sustained a late non Q myocardial infarction was asymptomatic. Of the remaining 20 patients the anginal class was 0-II in 19 and III in one. Rotational atherectomy can achieve excellent short and long term outcomes in selected octogenarians. (c)2000 by CVRR, Inc.

Journal Article↗

Percutaneous atherectomy as an alternative treatment for postangioplasty obstructive intimal flaps.

Intimal flaps are commonly seen angiographically after percutaneous balloon angioplasty. Nonobstructive flaps are normally of little clinical significance, but flaps that obstruct blood flow may lead to partial or complete thrombosis. The Simpson atherectomy catheter was used to treat obstructive intimal flaps after angioplasty in four patients. Lumen patency was reestablished in all four cases. The clinical results were excellent, with rest pain and claudication resolved in all four patients and distal pulses reestablished in one. These findings suggest that the Simpson atherectomy catheter can be used to remove large obstructive flaps complicating angioplasty.

Aged↗

The cause of superior vena cava syndrome: diagnosis with percutaneous atherectomy.

The cause of superior vena cava syndrome (SVCS) in two patients was identified by means of endovascular biopsy of the superior vena cava (SVC) performed with a percutaneous atherectomy catheter. In both cases, the extracted tissues were neoplastic, therefore obviating additional invasive procedures. After a specific diagnosis was established, external-beam radiation therapy was used to treat the SVCS. The atherectomy catheter was used in conjunction with other percutaneous techniques, including balloon angioplasty and endovascular stenting of the SVC.

Adenocarcinoma↗

Peripheral directional atherectomy: 4-year experience.

Directional atherectomy alone or with supplemental percutaneous transluminal angioplasty was used to treat peripheral vascular lesions in 77 patients (85 procedures). Lesions involved 17 iliac arteries, 45 infrainguinal arteries, and 23 laser extremity vein bypass grafts. Technical success, defined as reduction of stenosis diameter to 30% or less of the normal vessel diameter, was achieved in 78 of 85 (92%) cases. The complication rate was 21% (18 of 85 procedures). Most complications were minor and were related to puncture sites. Patients underwent noninvasive follow-up studies, including measurement of ankle-brachial index and segmental pressures, plethysmography, and clinical examination. The mean follow-up period was 13.5 months. The probability of 1-, 2-, and 3-year patency for lesions treated with atherectomy alone was 92%, 84%, and 84%, respectively. Kaplan-Meier survival analysis revealed no difference in 2- to 3-year patency rate on the basis of lesion location or presence of calcification, eccentricity, or ulceration. Diabetic patients, however, had a higher restenosis rate than did patients who were not diabetic (P less than .03).

Aged↗

Evidence implicating nonmuscle myosin in restenosis. Use of in situ hybridization to analyze human vascular lesions obtained by directional atherectomy.

BACKGROUND: Identification of genes that are specifically activated in restenosis lesions after percutaneous transluminal angioplasty represents a necessary step toward molecular manipulation designed to inhibit cellular proliferation responsible for such lesions. Whereas quiescent smooth muscle cells (contractile phenotype) preferentially express smooth muscle myosin, proliferating smooth muscle cells (synthetic phenotype) have been shown to preferentially express nonmuscle myosin in vitro. Accordingly, we analyzed the expression of a recently cloned isoform of human nonmuscle myosin heavy chain (MHC-B) in fresh human restenotic lesions. METHODS AND RESULTS: A total of 10 lesions, including four restenosis (three superficial femoral arterial lesions and one saphenous vein bypass lesion) and six primary (four superficial femoral arterial lesions and two coronary arterial lesions) obtained percutaneously by directional atherectomy, were processed for examination by in situ hybridization. In total, 150 tissue sections of restenotic lesions (66 sections), primary lesions (78 sections), and normal internal mammary artery (six sections) were hybridized with the nonmuscle MHC-B probe. Restenotic lesions showed intense hybridization to the nonmuscle MHC-B cRNA probe, as demonstrated by a clustering of more than 20 grains per cell nucleus in 80% of the cells examined within a high-power field (x250); in contrast, an equivalent degree of hybridization was observed in only 7% of cells within primary lesions (p less than 0.001). Results of immunocytochemistry using monoclonal antibody to smooth muscle actin indicated that cells demonstrating strong hybridization were smooth muscle in origin. CONCLUSIONS: These findings demonstrate that 1) human vascular tissue obtained by percutaneous directional atherectomy constitutes appropriate biopsy material for gene expression studies at the mRNA level, and 2) nonmuscle MHC-B mRNA is present in greater abundance among restenotic versus primary vascular stenoses. These observations thus provide a rational basis to explore restenotic lesions on a larger scale to identify genes that are activated in these lesions and establish potential targets for future gene therapy.

Arteriosclerosis↗

Migratory activity of human smooth muscle cells cultivated from coronary and peripheral primary and restenotic lesions removed by percutaneous atherectomy.

BACKGROUND: The successful cultivation of human smooth muscle cells (SMC) from coronary and peripheral atherosclerotic lesions removed by percutaneous directional atherectomy is described. METHODS AND RESULTS: Sixty-seven patients in whom plaque material was obtained compose the study population. A total of 73 lesions from both coronary (n = 38) and peripheral (n = 35) arteries of primary (n = 50) and restenotic origin (n = 23) were studied. Successful cultivation was significantly (p less than 0.001) dependent on the quantity of plaque material submitted. Fifty-five percent of patients in whom atherectomy specimens were removed from coronary lesions yielded an adequate SMC population in comparison to 89% of those from peripheral arteries (p less than 0.01). Cultivation was not dependent on the age and sex of patients, lesion origin, risk factors, medications, or incidence of unstable angina. In an attempt to quantify SMC activity, migratory velocity was measured with a computer-assisted motion analysis system. SMC migratory velocity was found to be significantly (p less than 0.001) greater in restenotic than in primary plaque material. This finding was confirmed for both coronary and peripheral lesions. CONCLUSIONS: Our data suggest that elevated SMC migratory activity may be an important mechanism in the development of restenotic lesions.

Aged↗