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.

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.

Directional atherectomy for treatment of restenosis within coronary stents: clinical, angiographic and histologic results.

OBJECTIVES: The safety and long-term results of directional coronary atherectomy in stented coronary arteries were determined. In addition, tissue studies were performed to characterize the development of restenosis. METHODS: Directional coronary atherectomy was performed in restenosed stents in nine patients (10 procedures) 82 to 1,179 days after stenting. The tissue was assessed for histologic features of restenosis, smooth muscle cell phenotype, markers of cell proliferation and cell density. A control (no stenting) group consisted of 13 patients treated with directional coronary atherectomy for restenosis 14 to 597 days after coronary angioplasty, directional coronary atherectomy or laser intervention. RESULTS: Directional coronary atherectomy procedures within the stent were technically successful with results similar to those of the initial stenting procedure (2.31 +/- 0.38 vs. 2.44 +/- 0.35 mm). Of five patients with angiographic follow-up, three had restenosis requiring reintervention (surgery in two and repeat atherectomy followed by laser angioplasty in one). Intimal hyperplasia was identified in 80% of specimens after stenting and in 77% after coronary angioplasty or atherectomy. In three patients with stenting, 70% to 76% of the intimal cells showed morphologic features of a contractile phenotype by electron microscopy 47 to 185 days after coronary intervention. Evidence of ongoing proliferation (proliferating cell nuclear antigen antibody studies) was absent in all specimens studied. Although wide individual variability was present in the maximal cell density of the intimal hyperplasia, there was a trend toward a reduction in cell density over time. CONCLUSIONS: Although atherectomy is feasible for the treatment of restenosis in stented coronary arteries and initial results are excellent, recurrence of restenosis is common. Intimal hyperplasia is a nonspecific response to injury regardless of the device used and accounts for about 80% of cases of restenosis. Smooth muscle cell proliferation and phenotypic modulation toward a contractile phenotype are early events and largely completed by the time of clinical presentation of restenosis. Restenotic lesions may be predominantly cellular, matrix or a combination at a particular time after a coronary procedure.

Management of intermediate coronary syndrome: role of conservative treatment, glycoprotein IIb/IIIa receptor inhibitors, and direct intervention.

Mortality rates in patients after myocardial infarction (MI) have decreased from a high of >50% in the 1930s to 10-15% currently, and even lower in some clinical trials. At present, much of the research is focused on (1) identifying patients at high risk despite the lack of typical prognosticators of a severe event; and (2) delineating the optimal therapy for patients with unstable angina or non-Q-wave MI. Clinicians are now focusing on acute coronary syndrome. Patients present with (1) minor electrocardiographic abnormalities; (2) chest pain; and (3) possible abnormalities in creatine kinase, creatine kinase-myocardial band, and troponin. The primary goal for these patients is to prevent plaque rupture and its associated morbidity and mortality. Aspirin and heparin are clearly indicated. The glycoprotein (GP) IIb/IIIa receptor inhibitors are even more effective in inhibiting platelet activation. Under what circumstances should these agents be used, and which of the 3 currently available agents is superior? Analysis of the trials addressing these questions clearly demonstrates the importance of these agents in this setting. The choice of agent is still unclear, pending a randomized, interdrug comparison. It also remains to be demonstrated whether low-molecular-weight heparin is superior to standard heparin in this setting and which patients should undergo angiography.

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.

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.

Influence of vessel selection on the observed restenosis rate after endoluminal stenting or directional atherectomy.

In comparing the restenosis rates among different interventions, 1 potential confounder might be the differences in the vessels treated, as dictated by the technical limitations of particular devices. The purpose of this study was to use current "acute gain-late loss" analysis to examine what influence vessel selection has on the restenosis rates seen after coronary stenting or directional atherectomy. The minimal luminal diameter of native coronary lesions was measured before and immediately after intervention in 102 single Palmaz-Schatz stents and 347 atherectomies, 367 (82%) of which had repeat angiographic measurement 6 months after intervention. Atherectomy-treated lesions had a higher proportion of left anterior descending to right coronary arteries (68 vs 24%) compared with stents (31 vs 54%), p < 0.001. Although subsequent restenosis rates were similar for stenting (25%) and atherectomy (30%, p = 0.42), left anterior descending versus right coronary lesions had a significantly higher restenosis rate for the overall group (35 vs 18%, p = 0.009), for stents (44 vs 13%, p = 0.008) and for atherectomy (35 vs 22%, p = 0.10), respectively. Multivariable analysis demonstrated that postprocedure luminal diameter (p = 0.03, p = 0.009) and coronary location (the proportion of left anterior descending vessels treated, p = 0.002, p < 0.001), but not device type (stent vs atherectomy), were strong independent determinants of restenosis according to both binary (> 50% diameter stenosis) and continuous (late percent stenosis) definitions.(ABSTRACT TRUNCATED AT 250 WORDS)

Directional atherectomy. New approaches for treatment of obstructive coronary and peripheral vascular disease.

Atherectomy is defined as the controlled removal of atherosclerotic tissue from vessel walls. The directional atherectomy catheter consists of a cup-shaped cutter within a housing unit and a small balloon. It was developed to perform transluminal atherectomy for the treatment of atherosclerotic vascular disease. This new procedure was performed on 195 lesions in peripheral arteries of lower limbs in 134 procedures, and 52 lesions in coronary arteries in 50 procedures. A successful angiographic outcome was obtained in 89% of procedures and 90% of lesions in peripheral experience, and 60% of procedures and 62% of lesions in coronary experience. A higher success rate (81%) was achieved in our more recent experience with coronary atherectomy, as compared with a 42% success rate in our earlier experience. The incidence of major complications was infrequent in both peripheral and coronary experiences. In the peripheral experience, one patient had delayed occlusion that required bypass surgery, and two patients had distal embolization. In the coronary experience, one patient had acute occlusion that required emergency bypass surgery. There were no vessel perforations. Conclusively, transluminal atherectomy is a feasible, predictable, and safe procedure for the treatment of peripheral and coronary artery disease. Further studies, however, are necessary to evaluate the long-term efficacy of this new procedure.

Directional coronary atherectomy complications and management.

Directional coronary atherectomy provides a predictable outcome in selected cases; however, DCA may still result in significant complications in a small number of patients. Although many of the complications are similar to those associated with PTCA, some of the complications are unique or more frequently observed with DCA. These complications are often preventable with adequate case selection and appropriate technique. Because of significant differences in the atherectomy procedure compared to PTCA, the operator should recognize and understand the technical differences to prevent potentially serious complications.

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.