Atherectomy Device Research Articles

Anatomy, histology, and pathology of coronary arteries: a review relevant to new interventional and imaging techniques--Part IV.

In the last 15 years, intense interest has focused on various interventional pharmacologic and mechanical forms of therapy for the treatment of atherosclerosis coronary artery disease. Many techniques and devices (dilating balloons, perfusion catheters, thermal probes and balloons, lasers, atherectomy devices, stents, intravascular ultrasound) have been used or are under study for future use. Many of these techniques and devices require an understanding of histologic and pathologic features of the coronary arteries and diseases which affect them. This article reviews selective areas of anatomy, histology, and pathology relevant to the use of various new interventional techniques. Part IV of this review will focus on congenital coronary artery anomalies, myocardial bridges, coronary aneurysm, emboli, and dissection and clinical implications regarding echocardiographic imaging techniques.

Anatomy, histology, and pathology of coronary arteries: a review relevant to new interventional and imaging techniques--Part III.

In the last 15 years, intense interest has focused on various interventional, pharmacologic, and mechanical forms of therapy for the treatment of atherosclerotic coronary artery disease. Many techniques and devices (dilating balloons, perfusion catheters, thermal probes and balloons, lasers, atherectomy devices, stents, intravascular ultrasound) have been used or are under study for future use. Many of these techniques and devices require an understanding of histologic and pathologic features of the coronary arteries and diseases which affect them. This article reviews selective areas of anatomy, histology, and pathology relevant to the use of various new interventional techniques. Part III of this four-part review focuses on eccentric and concentric plaques, formation of coronary thrombus, and status of the "infarct artery" after mechanical and pharmacologic forms of acute reperfusion therapy.

Status of Peripheral Atherectomy

So far, all atherectomy devices have failed to reduce the restenosis rate of standard balloon angioplasty. Despite actual removal, debulking, and even polishing of the atherosclerotic intima, the arterial wall trauma invariably incites intimal hyperplasia. Until the problem of restenosis can be solved, atherectomy will be limited to those instances when balloon angioplasty is ineffective or contraindicated. Each device has its own peculiarities. We prefer to use the Simpson catheter for eccentric lesions in the iliofemoral or femoropopliteal regions, the Auth Rotablator for short lesions in the infrageniculate vessels, and the TEC for longer lesions in the femoropopliteal regions. Adjunctive balloon angioplasty may or may not be required. Ahn and Moore have illustrated specific clinical strategies for peripheral atherectomy.

Directional Atherectomy Treatment for Hemodialysis Access: Early Results

The Simpson atherectomy device was used to treat 12 intragraft stenoses, six complete subclavian vein occlusions, and 14 venous outflow stenoses in 24 patients undergoing hemodialysis. Patients were followed up clinically and by means of venography at approximately 1, 3, 6, 9, and 12 months after treatment. Twenty-eight atherectomy specimens were examined histologically. Twenty-six (81%) of 32 lesions were treated with initial technical success. Including technical failures, seven (58%) of 12 intragraft stenoses are angiographically patent at a mean of 5.0 months and five (50%) of 10 are clinically patent at 6 months. Three (50%) of six subclavian veins are angiographically patent at a mean of 5.6 months, and four (67%) of six are clinically patent at 6 months. Three (21%) of 14 venous outflow stenoses are angiographically patent at a mean of 5.0 months and five (38%) of 13 are clinically patent at 6 months. Histologic examination showed neointimal fibromuscular hyperplasia in 26 of 28 lesions. When 30% or less angiographic residual stenosis is used as the criterion for initial technical success, directional atherectomy appears to be effective therapy for intragraft stenoses and, with balloon angioplasty, for some catheter insertion-related subclavian occlusions. Directional atherectomy appears to have a recurrence rate for venous outflow stenoses similar to that for balloon angioplasty when the same criterion is used.

Anatomy, histology, and pathology of coronary arteries: a review relevant to new interventional and imaging techniques--Part II.

In the last 15 years, intense interest has focused on various interventional, pharmacologic, and mechanical forms of therapy for the treatment of atherosclerotic coronary artery disease. Many techniques and devices (dilating balloons, perfusion catheters, thermal probes and balloons, lasers, atherectomy devices, stents, intravascular ultrasound) have been used or are under study for future use. Many of these techniques and devices require an understanding of histologic and pathologic features of the coronary arteries and diseases which affect them. This article reviews selective areas of anatomy, histology, and pathology relevant to the use of various new interventional techniques. Part II of this four-part review will focus on aging changes seen in the epicardial coronary arteries and will review selected features of atherosclerotic plaque, including fissure and topography.

Acute and long-term outcome of narrowed saphenous venous grafts treated by endoluminal stenting and directional atherectomy

Angioplasty of the narrowed saphenous vein bypass grafts remains a difficult challenge. Over a 37-month period at this institution, 119 of 176 interventions (68%) on saphenous vein grafts (average age 8.3 years from bypass surgery to graft intervention) were performed using either directional coronary atherectomy (n = 35) or Palmaz-Schatz intracoronary stents (n = 84), representing 37% of all stents and 15% of all atherectomies during the study period, respectively. Of the 57 saphenous vein graft lesions treated with conventional balloon angioplasty during this period, 49 (86%) had 1 or more contraindications to stenting or directional atherectomy (thrombus, total occlusion, reference vessel <3 mm in diameter). The acute success rate was 99% for stents (1 failure to dilate) and 94% for directional atherectomy (2 failures to cross the lesion with the atherectomy device). Lumen diameter increased from 0.9 to 3.6 mm (reference vessel 3.6) for stents, and from 0.9 to 3.5 mm (reference 3.8) for atherectomy (for all comparisons, p = not significant), with no major complications (abrupt or subabrupt closure, emergent coronary bypass surgery, death, or Q-wave myocardial infarctions). During the same time period 50 of 57 vein grafts (88%) rejected for stenting or atherectomy were dilated successfully by conventional balloon angioplasty, with 3 patients (5%) requiring emergent coronary bypass surgery. Angiographic follow-up was available for 50 of 64 eligible patients (78%). Restenosis (defined as ≥50% stenosis at 6-month angiographic follow-up) was present in 13 of 50 lesions (26%, [95% confidence interval: 14%, 38%]), including 8 of 32 stented lesions (25%) and 5 of 18 atherectomy lesions (28%) (p = not significant). These data suggest that saphenous vein bypass graft stenoses may be treated safely and effectively using Palmaz-Schatz stenting or directional atherectomy, with short- and long-term results that may be better than those traditionally expected with conventional balloon angioplasty.

Anatomy, histology, and pathology of coronary arteries: a review relevant to new interventional and imaging techniques--Part I.

In the last 15 years, intense interest has focused on various interventional pharmacologic and mechanical forms of therapy for the treatment of atherosclerosis coronary artery disease. Many techniques and devices (dilating balloons, perfusion catheters, thermal probes and balloons, lasers, atherectomy devices, stents, intravascular ultrasound) have been used or are under study for future use. Many of these techniques and devices require an understanding of histologic and pathologic features of the coronary arteries and diseases which affect them. This article reviews selective areas of anatomy, histology, and pathology relevant to the use of various new interventional techniques. Part I of this review will focus on anatomic aspects of the epicardial coronary artery system, coronary arterial distribution, myocardial supply, and histologic features of the normal coronary artery.

Changing trends for surgical standby in patients undergoing percutaneous transluminal coronary angioplasty

In 1988 the American College of Cardiology/ American Heart Association (ACC/AHA) task force subcommittee on Guidelines for Percutaneous Transluminal Coronary Angioplasty (PTCA) recommended that an experienced cardiovascular surgical team be available within the institution for emergency surgery for all angioplasty procedures. The subcommittee felt strongly that this requirement allowed for no exception, stating that it could not condone existing arrangements that required the transportation of patients to off-site surgical facilities for emergency cardiac surgery. Such arrangements failed to meet the necessary standards of care exercised by prudent physicians. Interventional cardiologists are recognizing that it may be prudent for the ACC/ AHA task force to revise its 1988 guidelines. Improved operator technique and new technologic advances, such as lasers, atherectomy devices, stents, and perfusion pumps and balloons, have helped extend the reach of PTCA to more seriously ill patients. With new technologies for angioplasty and an increased awareness of risk factors, active standby can be markedly reduced, thereby resulting in enormous cost reductions and in more appropriate patient care.

Novel coronary interventional devices: An update

Interventional cardiologists today are over-whelmed by a hugh array of new high technology investigatory devices at their disposal for the treatment of coronary arterial obstructive disease. These include the various atherectomy and laser devices, developed and introduced into clinical practice with the promise and intent of solving the limitations of conventional balloon angioplasty, namely those of acute closure and restenosis. But as more experience and data are obtained from the application of these devices, it is becoming clear that the latter have generally not been able to accomplish what they were intended to do. Although the immediate success rates have been uniformly high, acute closure has persisted and restenosis remains unabated. Nevertheless, some of these new devices have shown some fairly encouraging results in specific clinical circumstances. The targeted use of these instruments may prove to be a step in the right direction. This article reviews the current state of the art and the potential utility of certain of these devices.

Antistenosis Approaches Revisited, or Rating the Artery Openers Anew

CLEARING OUT the recurrent underbrush of fatty debris in the arterial jungle is the goal of cardiologic explorers today. Despite the nearly routine restoration of blood flow through once-clogged coronary vessels that makes possible, restenosis continues to be a problem. Following attack by blasting, cutting, scraping, melting, and other efforts, the plaque comes back. At the 64th annual Scientific Sessions of the American Heart Association (AHA), held in Anaheim, Calif, many presentations dealt with the safety and efficacy of alternative devices designed during the past few years to remove fatty deposits or prop open arterial walls after percutaneous transluminal coronary angioplasty (PTCA). Sometimes the new methods are tried first. In either case, success has not been great. Experimental Now, Clinical in '92? The major devices include specialized balloon and laser catheters, mechanical atherectomy or ablation devices, and metallic and bioabsorbable stents. With one exception (the Atherocath, which has

Antistenosis approaches revisited, or rating the artery openers anew

CLEARING OUT the recurrent underbrush of fatty debris in the arterial jungle is the goal of cardiologic explorers today. Despite the nearly routine restoration of blood flow through once-clogged coronary vessels that "balloon angioplasty" makes possible, restenosis continues to be a problem. Following attack by blasting, cutting, scraping, melting, and other efforts, the plaque comes back. At the 64th annual Scientific Sessions of the American Heart Association (AHA), held in Anaheim, Calif, many presentations dealt with the safety and efficacy of alternative devices designed during the past few years to remove fatty deposits or prop open arterial walls after percutaneous transluminal coronary angioplasty (PTCA). Sometimes the new methods are tried first. In either case, success has not been great. <h3>Experimental Now, Clinical in '92?</h3> The major devices include specialized balloon and laser catheters, mechanical atherectomy or ablation devices, and metallic and bioabsorbable stents. With one exception (the Atherocath, which has

Effects of rotational atherectomy in normal canine coronary and diseased human cadaveric arteries: Potential for plaque removal from distal, tortuous, and diffusely diseased vessels

To test the hypothesis that tortuous, diseased vessels could be successfully treated with a flexible rotational atherectomy device we evaluated the BARD atherectomy device with quantitative angiography and histology in normal canine coronary arteries and diseased human below-knee amputation specimens. The mid left anterior descending and the circumflex vessels were treated in 4 dogs serially with 1 wk separating treatments. The acute and follow-up anterior descending artery size was unchanged (1.41 mm before, 1.39 mm after, and 1.59 mm at 1 week). Similar findings were obtained in the circumflex vessels. In 4 adult human amputated legs, diseased peroneal or tibial arteries were treated with a significant reduction in the percent luminal diameter stenosis from 62.75 prior to intervention to 36.5 following intervention (p = 0.021). The luminal diameter increased from 0.81 to 1.54 mm (p = 0.06). In 2 canine arteries there was histologic evidence of localized perforation of the arterial wall, but there was no angiographic evidence of perforation or dissection and no significant myocardial necrosis in the distribution of the treated vessels at 1 wk. The majority of the diseased human vessels demonstrated smoothly cut atheromas with sparing of the media. The rotational atherectomy catheter system holds promise for removal of plaque in relatively small, diffusely diseased, tortuous vessels.

Clinical, angiographic and procedural correlates of quantitative coronary dimensions after directional coronary atherectomy

To define the clinical, angiographic and procedural correlates of quantitative coronary dimensions after directional coronary atherectomy, 400 lesions in 378 patients were analyzed with use of qualitative morphologic and quantitative angiographic methods. Successful atherectomy, defined by a <75% residual area stenosis, tissue retrieval and the absence of in-hospital ischemic complications, was performed in 351 lesions (87.7%). After atherectomy, minimal cross-sectional area increased from 1.2 ± 1.1 to 6.6 ± 4.4 mm2(p < 0.001) and percent area stenosis was reduced from 87 ± 10% to 31 ± 42% (p < 0.001).By univariate analysis, device size (p < 0.001) and left circumflex artery lesion location (p = 0.004) were associated with a larger final minimal cross-sectional area. Conversely, restenotic lesion (p = 0.002), lesion length ≥ 10 mm (p = 0.018) and lesion calcification (p = 0.035) were quantitatively associated with a smaller final minimum cross-sectional area. With use of stepwise multivariate analysis to control for the reference area, atherectomy device size (p = 0.003) and left circumflex lesion location (p = 0.007) were independently associated with a larger final minimal cross-sectional area, whereas restenotic lesion (p = 0.010), diffuse proximal disease (p = 0.033), lesion length ≥ 10 mm (p = 0.026) and lesion calcification (p = 0.081) were significantly correlated with a smaller final minimal cross-sectional area. The number of specimens excised, the number of atherectomy passes and atherectomy balloon inflation pressure did not correlate with the final minimal cross-sectional area.Thus, directional atherectomy results in marked improvement of coronary lumen dimensions, at least in part correlated with the presence of certain clinical, angiographic and procedural factors at the time of atherectomy.

The naci registry: An instrument for the evaluation of new approaches to coronary intervention

The New Approaches to Coronary Intervention (NACI) Registry was developed to collect in-depth data about patients whose coronary artery lesions are being treated with new interventional techniques such as atherectomy, stents, and laser devices. The NACI Registry database distinguishes among several possible "modes" for device use, such as preparatory, planned definitive, and bailout use. Common definitions are used for data collection across all devices, and device-specific forms are used to record procedural details. NACI's unique modular form design facilitates thorough data collection, even for the most complex treatment scenarios. The database structure allows for data analysis at the patient, procedure, lesion, and device levels, as required to perform in-depth analyses of the immediate and long-term success of new devices. Once adequate knowledge of basic device performance has been collected, the Registry structure can also allow expeditious planning and performance of randomized trials comparing a new device to conventional PTCA.

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)

Quantitative angiography after directional coronary atherectomy.

To assess by quantitative analysis the immediate angiographic results of directional coronary atherectomy. To compare the effects of successful atherectomy with those of successful balloon dilatation in a series of patients with matched lesions. Case series. Tertiary referral centre. 62 patients in whom directional coronary atherectomy was attempted between 7 September 1989 and 31 December 1990. Directional coronary atherectomy. Increase in minimal luminal diameter of coronary artery segment. Angiographic success on the basis of intention to treat was obtained in 54 patients (87%). In four patients the lesion could not be crossed by the atherectomy device; all four had an uneventful conventional balloon angioplasty. Four of the 58 patients who underwent atherectomy were subsequently referred for coronary bypass surgery because of failure or complications; three of them sustained a transmural infarction. In the successful cases, coronary atherectomy resulted in an increase in the minimal luminal diameter from 1.1 mm to 2.5 mm with a concomitant decrease of the diameter stenosis from 62% to 22%. In the subset of 37 patients in which the changes induced were compared with conventional balloon angioplasty atherectomy increased the minimal luminal diameter more than balloon angioplasty (1.6 v 0.8 mm; p less than 0.0001). Conventional histology showed media or adventitia in 26% of the atherectomy specimens. In hospital complications occurred in six patients who had undergone a successful procedure: two transmural infarctions, two subendocardial infarctions, one transient ischaemia attack, and one death due to delayed rupture of the atherectomised vessel. All patients were clinically evaluated at one and six months. One patient had persisting angina (New York Heart Association class II), one patient sustained a myocardial infarction, one patient underwent a percutaneous transluminal coronary angioplasty for early restenosis, and one patient underwent coronary bypass surgery because of a coronary aneurysm formation. At six months 80% (36/47) of the patients were symptom free. Coronary atherectomy achieved a better immediate angiographic result than balloon angioplasty; however, in view of the complication rate in this preliminary series, which may be related to a learning curve, a randomised study is needed to show whether this procedure is as safe as a conventional balloon angioplasty.

Histologic and Morphologic Effects of Rotary Atherectomy on Human Cadaver Arteries

Intimal splitting and medial dissection caused by balloon angioplasty and thermal burns and subintimal vacuolization caused by laser angioplasty have been proposed as potential causes of failure from these respective procedures. The purpose of this study was to evaluate the histologic and morphologic effects of a new high speed rotary atherectomy device (the Rotoblator) on human cadaver arteries. Fifteen stenotic human cadaver superficial femoral and popliteal arteries were harvested and atherectomized using the Rotoblator. Histologically, on cross-section, the atherectomized arteries exhibited a denuded endothelial layer, a smooth rounded luminal contour, minute plaque separation from the media, absence of plaque fragmentation, and variable remaining rim of atheromatous plaque. The media showed variable loss of the internal elastic lamina, normal remaining elastin, and normal smooth muscle cells. The adventitia was normal and completely intact in all sections with no media/adventitia separation or perforations. Scanning electron microscopy revealed endothelial peeling, etching from the atherectomy devices within the smooth muscle layer, and a tapered atherectomy distal endpoint. The arterial branches were preserved without evidence of any disruption of the branch artery orifice. Compared to balloon angioplasty and laser angioplasty, the Rotoblator atherectomy device appears to leave a smoother, more rounded luminal surface that may result in less risk of embolic complications and arterial wall damage.

New uses of the laser in thoracic and cardiovascular surgery

Lasers have been accepted in general thoracic surgery as resectional tools which allow precise hemostasis and maximal salvage of normal lung tissue. Used endoscopically, with or without associated photodynamic therapy, we have provided acceptable palliation in some patients with obstructing tumors of the tracheobronchial tree and esophagus. Cardiovascular uses of the laser have been under extensive investigation at our medical center for many years. We have demonstrated that laser-assisted anastomosis of small vessels is possible, that early tensile strength and patency are excellent, but that long-term aneurysm formation is excessive. In addition, CO2 laser injury of the arterial intima leads to a marked increase in atheromata formation in animal models of atherosclerosis; this may be eliminated with the excimer laser. We have begun using the excimer laser to open obstructed peripheral and coronary arteries. New technology is emerging which allows dual fiber catheters which allow identification of tissue in an artery, ie calcium, atheromata, clot, media, etc. and instantaneous computer sensing/integration which initiates "fire" or "no fire" signals in the enclosed laser system, thus decreasing the chance of vessel perforation. These technologies, in association with balloon angioplasty, intravascular stents, and atherectomy devices are offering exciting alternate therapy for patients with obstructing atherosclerosis.

Current techniques for infrainguinal arterial reconstruction

Infrainguinal reconstruction for peripheral vascular occlusive disease comprises an increasingly complex array of interventions which provide unparalleled options for the salvage of threatened limbs. Conventional autogenous saphenous vein bypass remains the most durable revascularization with anticipated graft patency rates approaching 80 percent after five years and excellent long term limb salvage. These excellent results are equally applicable to vein grafts carried to infrapopliteal and even inframalleolar levels, possibly reflecting increased utilization of the in situ method. Although 20 per cent of grafts fail within five years, secondary intervention results in sustained limb salvage in the majority of patients. In the absence of autogenous vein, however, prosthetic material performs poorly such that new interventions consisting of percutaneous transluminal angioplasty, rotary atherectomy devices and laser systems are under aggressive development. Although initial results with these devices are encouraging, long term patency rates remain poor largely due to restenosis. Further progress seems to depend primarily on an increased understanding of the natural healing response of the injured artery.

Peripheral Atherectomy: Experimental Results with a New Device

The size of present rotational atherectomy devices is limited in part by a tendency to produce vessel torsion. The authors designed and investigated a large-bore rotational atherectomy device for peripheral atherectomy in a single pass without significant torsion. A plaque was retrieved from 36 of 40 cadaveric iliac arteries. The mean plaque size was 8.4 x 3.9 mm, and the average number retrieved per artery was two. Thirty of 34 severely calcified arteries were treated successfully. Effluent study revealed no distal embolization; however, six perforations and four dissections occurred. Preliminary results suggest that a cutting surface with a relatively large diameter can be designed to be effective without producing vessel torsion. Changes in future designs will include added flexibility and expandable cutting surfaces to enhance safety and minimize entry diameter.