Matthew R. Selmon

Percutaneous recanalization of chronically occluded coronary arteries: A consensus document - Part II

In Part I of this article, the definitions, prevalence, and clinical presentation of chronic total occlusions (CTOs) were reviewed, the histopathology of CTOs was examined, efforts to replicate human CTOs with experimental models were appraised, and the clinical relevance and rationale for CTO revascularization were evaluated.1 In Part II, we summarize the technical approach to and outcomes after percutaneous coronary intervention (PCI) of occluded coronary arteries, describe the novel devices and drugs approved and undergoing investigation for CTO recanalization, and conclude with practical perspectives on managing the patient with 1 or more chronic coronary occlusions. ### Patient Selection and Revascularization Strategies PCI of CTOs constitutes as many as 20% of all angioplasty procedures at selected centers,2 although a rate of &10% is more typical,3–6 suggesting that CTO angioplasty is attempted in 50 000 to 100 000 patients per year in the United States. Many more CTOs are present for which PCI is never attempted, representing one of the most common causes for referral to bypass surgery rather than PCI.6–8 Furthermore, a large proportion of patients with CTOs are managed medically, the prognosis of whom may vary depending on the extent of viable myocardium and ischemia, concomitant atherosclerosis in other coronary and noncoronary vascular territories, and other comorbid conditions. The decision to attempt PCI of a CTO (versus continued medical therapy or surgical revascularization) requires an individualized risk/benefit analysis, encompassing clinical, angiographic, and technical considerations. Clinically, the patient’s age, symptom severity, associated comorbidities (eg, diabetes mellitus and chronic renal insufficiency), and overall functional status are major determinants of treatment strategy. Angiographically, the extent and complexity of coronary artery disease (eg, single-vessel versus multivessel disease, single versus multiple total occlusions, likelihood for complete revascularization), left ventricular function, and the presence and degree of valvular heart disease should be considered. The technical probability of achieving …

Transluminal atherectomy for occlusive peripheral vascular disease.

Sixty-one patients with occlusive peripheral vascular disease were treated with transluminal atherectomy, a catheter-mediated technique for removal of atheroma. The technique was performed using 7Fr, 9Fr or 11Fr atherectomy catheters. Mean percent diameter stenosis was reduced from 71 to 23%, by removal of 831 atheromatous specimens in 949 passes of the cutting element through 136 stenoses in 61 patients. All specimens removed were sent for histopathologic examination to determine the components of the atheroma removed, which differed for specimens removed from original vs restenotic lesions. Percent stenosis was reduced to less than 45% in 118 of 136 stenoses (87%). Complications included 1 thrombus, which resolved after intraarterial infusion of streptokinase and 1 probable distal embolization without sequelae. Three angiographic dissections occurred without impairment of blood flow. There were no instances of acute occlusion, vascular spasm or vessel perforation. Six-month follow-up angiography was performed showing that patients who had a residual stenosis less than 30% after initial atherectomy had a lower restenosis rate (18%) than patients with initial residual stenoses greater than 30% (52%); this result demonstrated the importance of performing more complete atherectomy. Transluminal atherectomy appears to be an effective, predictable and safe method for removing occlusive atheromatous deposits from peripheral arteries.

Primary peripheral arterial stenoses and restenoses excised by transluminal atherectomy: a histopathologic study.

Atherectomy is a new therapeutic intervention for the treatment of peripheral arterial disease, and permits the controlled excision and retrieval of portions of stenosing lesions. The gross and light microscopic features of 218 peripheral arterial stenoses resected from 100 patients by atherectomy were studied. One hundred seventy of these lesions were primary stenoses and 48 were restenoses subsequent to prior angioplasty or atherectomy. Microscopically, primary stenoses were composed of atherosclerotic plaque (150 lesions), fibrous intimal thickening (15 lesions) or thrombus alone (5 lesions). Atherosclerotic plaques had a variable morphology and, in one-third of cases, were accompanied by abundant surface thrombus that probably added to the severity of stenosis. Most patients with fibrous intimal thickening or thrombus alone had typical atherosclerotic plaque removed elsewhere from within the same artery. Intimal hyperplasia, with or without underlying residual plaque, was found at 36 sites of restenosis, the remaining 12 consisting of plaque only. Intimal hyperplasia had a distinctive histologic appearance and was due to smooth muscle cell proliferation within a loosely fibrous stroma. Superimposed thrombus may have contributed to arterial narrowing in 25% of hyperplastic and 8% of atherosclerotic restenoses (p = 0.41). Pathologic examination of tissues recovered by peripheral atherectomy is an important adjunct that may provide insight into the efficacy of vascular interventions and the phenomenon of postintervention restenosis.

Angioplasty in total coronary artery occlusion: Experience in 76 consecutive patients

The influence of multiple clinical, angiographic and technical variables on the outcome of percutaneous transluminal coronary angioplasty was evaluated in a group of 76 consecutive patients with total coronary artery occlusion. Angioplasty was performed successfully in 53% of these patients. The likelihood of successful angioplasty was favorably influenced by: 1) a history of prior myocardial infarction in the distribution of the occluded arterial segment (p = 0.03); 2) an estimated maximal duration of arterial occlusion of less than 20 weeks (p less than 0.001); and 3) a length of nonvisualized arterial segment distal to the point of occlusion of less than 1.5 cm (p = 0.03). The outcome of coronary angioplasty was not significantly influenced by the vessel involved, the location of the occlusion within an involved vessel, the morphology of the occlusion (tapered versus abrupt) or the age and sex of the patient. There were no deaths and no vascular perforations. Four patients had recurrent coronary occlusion within 24 hours of the procedure; in three of these, recurrent occlusion was successfully treated with reangioplasty and in one, emergent surgical revascularization was performed. Embolic occlusion of an arterial branch distal to the point of total coronary occlusion occurred in 4 of the 40 successfully recanalized arteries. Seventy-five percent of patients having successful recanalization of an occluded coronary artery were free of the anginal symptoms that had prompted performance of the procedure at a mean follow-up period of 7.3 months. Thus, angioplasty of a total coronary artery occlusion can be performed safely and effectively, particularly in patients with a history of prior myocardial infarction, a brief estimated duration of coronary occlusion and a short nonvisualized occluded arterial segment.

Effect of lesion characteristics on outcome of directional coronary atherectomy

Directional coronary atherectomy, a new transluminal procedure for treatment of obstructive lesions in coronary arteries by excision and removal of tissue, was performed on 447 lesions in 382 procedures. Successful outcome, defined as a reduction of stenosis by greater than or equal to 20% with a less than 50% residual stenosis, was achieved in 89.5% of lesions and mean stenosis was reduced from 75.9 +/- 13.3% to 14.5 +/- 22.1% (p less than 0.001). Complications included vessel occlusion during the procedure, 2.4%; vessel occlusion after the procedure, 1.3%; new lesion, 0.5%; nonobstructive guiding catheter-induced dissection, 0.3%; perforation, 0.8%; distal embolization, 2.1%; Q wave myocardial infarction, 0.8% and non-Q wave myocardial infarction, 4.2%. Twelve patients (3.1%) required coronary artery bypass surgery for these complications. The atherectomy success rate was greater than 80% and the combined atherectomy and angioplasty success rate was greater than 90% for complex morphologic features such as eccentric lesions, lengthy lesions, lesions with abnormal contour, angulated lesions, ostial lesions and lesions with branch involvement. In the presence of calcific deposition, atherectomy success rate was 52% for primary lesions and 83% for restenosed lesions. Among angiographically complex lesions, calcium was the predictor for failed atherectomy (p less than 0.0001). In summary, directional coronary atherectomy is safe and effective for treatment of obstructive lesions in coronary arteries in selected cases. In particular, it achieves a high success rate in lesions with complex morphologic characteristics, such as eccentricity, abnormal contour and ostial involvement.

Percutaneous recanalization of chronically occluded coronary arteries: Procedural techniques, devices, and results

Gregg W. Stone,* MD, Antonio Colombo, MD, Paul S. Teirstein, MD, Jeffrey W. Moses, MD, Martin B. Leon, MD, Nicolaus J. Reifart, MD, Gary S. Mintz, MD, Angela Hoye, MBchB, David A. Cox, MD, Donald S. Baim, MD, Bradley H. Strauss, MD, PhD, Matthew Selmon, MD, Issam Moussa, MD, Takahiko Suzuki, MD, Hideo Tamai, MD, Osamu Katoh, MD, Kazuaki Mitsudo, MD, Eberhard Grube, MD, Louis A. Cannon, MD, David E. Kandzari, MD, Mark Reisman, MD, Robert S. Schwartz, MD, Steven Bailey, MD, George Dangas, MD, PhD, Roxana Mehran, MD, Alexander Abizaid, MD, and Patrick W. Serruys MD, PhD

Restenosis after directional coronary atherectomy

OBJECTIVES This study evaluates the incidence of restenosis after successful directional coronary atherectomy and identifies risk factors for restenosis. BACKGROUND Directional coronary atherectomy has been shown to be a safe and effective treatment of obstructive coronary artery disease; however, information regarding restenosis is limited. METHODS Between October 1986 and December 1989, 289 patients with 332 lesions were successfully treated with directional coronary atherectomy and followed up prospectively. Clinical follow-up information was available for 98% and angiographic follow-up information was obtained for 82% at approximately 6 months, or earlier if symptoms recurred. Angiograms were quantitatively analyzed. Restenosis was defined as greater than 50% stenosis at the site of intervention. RESULTS Seventy-four percent of patients were either asymptomatic or clinically improved after the procedure. Thirty-two percent were subsequently treated by coronary artery bypass surgery (14%), percutaneous transluminal coronary angioplasty (4%) or repeat atherectomy (13%). Angiographic evidence of restenosis was observed in 42%. The restenosis rate in native coronary arteries was 31% for primary lesions and 28% and 49%, respectively, for lesions treated with one or two previous angioplasty procedures. The restenosis rate for saphenous vein grafts was 53% for primary lesions and 58% and 82%, respectively, for lesions treated with one or two previous angioplasty procedures. The median interval to angiographically documented restenosis was 133 days. A higher restenosis rate was associated with a saphenous vein graft, hypertension, a longer lesion (greater than or equal to 10 mm), a smaller vessel diameter (less than 3 mm), a noncalcified lesion and use of a smaller (6F) device. CONCLUSIONS Restenosis remains a limitation of directional coronary atherectomy. A subset of patients with larger vessels, shorter lesions or lesions treated with a larger (7F) device may have a more favorable outcome.

Comparison of dissection rates and angiographic results following directional coronary atherectomy and coronary angioplasty

Directional coronary atherectomy is a new percutaneous transluminal technique for treating occlusive coronary artery disease. In this study, angiographic results (i.e., residual stenosis and angiographic evidence of postprocedure dissection) after directional coronary atherectomy and balloon angioplasty were compared. The atherectomy group consisted of 91 lesions in 83 consecutive patients who underwent either left anterior descending artery or right coronary artery atherectomy. The angioplasty group consisted of 91 lesions in 84 patients that were matched with the atherectomy lesions with respect to vessel and whether the lesion was a restenosis lesion. The mean preprocedure diameter stenosis was 76% in both groups as measured quantitatively with electronic calipers. After the procedure, the mean residual diameter stenosis of the atherectomy lesions was 13 +/- 17%, whereas for the angioplasty lesions it was 31 +/- 18% (p less than 0.001). Success rates in both groups were similar (94.5 and 93.4%, respectively). The incidence of postprocedure dissection was 11% in the atherectomy group and 37% in the angioplasty group (p less than 0.0001). Directional coronary atherectomy results in significantly improved postprocedure angiographic appearances due to significantly less severe residual stenosis and lower incidence of dissection.

Clinical applications of intravascular ultrasound imaging in atherectomy

This paper discusses the potential application of intravascular ultrasound imaging in the context of catheter-based atherectomy. The advantages and limitations of ultrasound in this application are discussed, and representative cases are presented.

Restenosis: Directional Coronary Atherectomy

The concept of atherectomy was developed by J. B. Simpson to overcome some of the limitations of PTCA with the hypothesis that removal of tissue from an obstructed vessel would create a smooth and wide lumen [1, 2]. A smooth, wide lumen without dissection may prevent acute occlusion or reduce thrombus formation, thus improving the acute outcome. Improved flow pattern may prevent platelet aggregation or thrombus formation which are potential triggers for smooth muscle cell proliferation. Furthermore, a wide lumen following intervention may allow some intimal hyperplastic tissue to grow during the healing process without creating a hemodynamically significant stenosis. There is, therefore, the potential that atherectomy may reduce restenosis.