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.     

Quantitative angiography after directional coronary atherectomy.

OBJECTIVE--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. DESIGN--Case series. SETTING--Tertiary referral centre. PATIENTS--62 patients in whom directional coronary atherectomy was attempted between 7 September 1989 and 31 December 1990. INTERVENTIONS--Directional coronary atherectomy. MAIN OUTCOME MEASURES--Increase in minimal luminal diameter of coronary artery segment. RESULTS--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. CONCLUSIONS--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.     

Quantitative angiography after directional coronary atherectomy

OBJECTIVE--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. DESIGN--Case series. SETTING--Tertiary referral centre. PATIENTS--62 patients in whom directional coronary atherectomy was attempted between 7 September 1989 and 31 December 1990. INTERVENTIONS--Directional coronary atherectomy. MAIN OUTCOME MEASURES--Increase in minimal luminal diameter of coronary artery segment. RESULTS--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. CONCLUSIONS--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.     

Mechanisms of acute gain and late lumen loss after atherectomy in different preintervention arterial remodeling patterns

The main mechanism of restenosis after directional coronary atherectomy (DCA) remains obscure. We investigated mechanisms of restenosis after DCA in different coronary artery remodeling patterns. DCA was performed in 51 de novo lesions. The lesions were evaluated by intravascular ultrasound (IVUS) before, immediately after, and 6 months after the procedure. According to the IVUS findings before DCA, we classified the lesions into the following 3 groups: (1) positive (n = 10), (2) intermediate (n = 25), and (3) negative (n = 16) remodeling. We measured lumen area, vessel area, and plaque area using IVUS before DCA, immediately after DCA, and at follow-up. Lumen area increase after DCA was mainly due to plaque area reduction in the positive and intermediate remodeling groups (90 plus minus 15% and 80 plus minus 25% increase in lumen area, respectively), whereas that in the negative remodeling group was due to both plaque area reduction (57 plus minus 22% increase in lumen area) and vessel area enlargement (43 plus minus 33% increase in lumen area). The plaque area increase correlated strongly with late lumen area loss in the positive and intermediate remodeling groups (r = 0.884, p <0.001; r = 0.626, p <0.001, respectively), but the decrease in vessel area was not correlated with lumen area loss. In contrast, both an increase in plaque area and a decrease in vessel area were correlated with late lumen area loss (r = 0.632, p = 0.009; r = 0.515, p = 0.041) in the negative remodeling group. Coronary artery restenosis after atherectomy was primarily due to an increase in plaque in the positive and/or intermediate remodeling groups. However, in the negative remodeling group, late lumen loss might have been caused by both an increase in plaque and vessel shrinkage.     

Increased expression of interleukin-10 in unstable plaque obtained by directional coronary atherectomy.

AIMS: The present study investigates the expression and localization of interleukin (IL)-10, an important anti-inflammatory cytokine, in atherectomy specimens from patients with stable and unstable angina. METHODS AND RESULTS: Twenty-two patients with stable angina and 21 with unstable angina who underwent directional coronary atherectomy for de novo lesions were studied. The atherectomy specimens were morphologically assessed and immunohistochemically stained with antibodies for IL-10, macrophages, smooth muscle cells, and endothelial cells. The localization and immunopositive areas were evaluated using an image analysing system. Immunoreactivity for IL-10 was detected in coronary plaques, especially in macrophages. Immunopositive areas of macrophages and IL-10, as well as the incidence of thrombus formation, were significantly greater in specimens from patients with unstable angina than in those from patients with stable angina (macrophages, P<0.001; IL-10, P<0.05; thrombus formation, P<0.05; respectively). Even after adjustment, IL-10 expression and the incidence of thrombus formation were significantly greater in the unstable angina group (P<0.05, each). The immunoreactivities for smooth muscle cells and endothelial cells did not differ between the two groups. CONCLUSION: IL-10 was more frequently expressed in specimens from patients with unstable angina. This finding might contribute to a better understanding of plaque instability.     

Recurrent unstable angina after directional coronary atherectomy is related to the extent of initial coronary plaque inflammation

OBJECTIVES: This study was performed to evaluate the relationship between plaque inflammation of the initial culprit lesion and the incidence of recurrent angina for one year after directional coronary atherectomy (DCA). BACKGROUND: A positive correlation between coronary plaque inflammation and angiographic restenosis has been reported. METHODS: A total of 110 patients underwent DCA. Cryostat sections were immunohistochemically stained with monoclonal antibodies CD68 (macrophages), CD-3 (T lymphocytes) and alpha-actin (smooth muscle cells [SMCs]). The SMC and macrophage contents were planimetrically quantified as a percentage of the total tissue area. T lymphocytes were counted as the number of cells/mm2. The patients were followed for one year to document recurrent unstable angina pectoris (UAP) or stable angina pectoris (SAP). RESULTS: Recurrent UAP developed in 16 patients, whereas recurrent SAP developed in 17 patients. The percent macrophage areas were larger in patients with recurrent UAP (27 +/- 12%) than in patients with recurrent SAP (8 +/- 4%; p = 0.0001) and those without recurrent angina (18 +/- 14%; p = 0.03). The number of T lymphocytes was also greater in patients with recurrent UAP (25 +/- 14 cells/mm2) than in patients with recurrent SAP (14 +/- 8 cells/mm2; p = 0.02) and those without recurrent angina (14 +/- 12 cells/mm2; p = 0.002). Multiple stepwise logistic regression analysis identified macrophage areas and T lymphocytes as independent predictors for recurrent UAP. CONCLUSIONS: There is a positive association between the extent of initial coronary plaque inflammation and the recurrence of unstable angina during long-term follow-up after DCA. These results underline the role of ongoing smoldering plaque inflammation in the recurrence of unstable angina after coronary interventions.     

Influence of plaque morphology on the mechanism of luminal enlargement after directional coronary atherectomy and balloon angioplasty.

OBJECTIVE--To relate the mechanism of luminal gain after directional atherectomy and balloon angioplasty to the morphological characteristics of the coronary lesions, assessed by intravascular ultrasound imaging. DESIGN--Intravascular ultrasound imaging was performed before and after the revascularisation procedure to assess the contribution of wall stretching and plaque reduction in luminal gain. SUBJECTS--32 patients undergoing balloon angioplasty and 29 undergoing directional coronary atherectomy. MAIN RESULTS--The main luminal area in vessels treated by balloon angioplasty increased from 1.51 (SD 0.30) to 3.91 (1.09) mm2 (P < 0.0001) with a concomitant increase in total vessel area from 11.44 (2.73) to 13.07 (2.83) mm2 (P < 0.0001). Therefore stretching of the vessel wall accounted for 68% of the luminal gain while plaque reduction accounted for the remaining 32%. This mechanism ranged from 45% in non-calcific plaques to 81% in echogenic plaques. The main luminal area in vessels treated by directional atherectomy increased from 1.49 (0.32) to 4.68 (1.73) mm2 (P < 0.0001), with a concomitant increase of total vessel area from 13.61 (4.67) to 15.2 (4.04) mm2 (P = 0.006). Thus stretching of the vessel wall accounted for 49% of the luminal area gain and plaque reduction for the remaining 51%. The presence of calcium influenced the relative contribution of these two mechanisms to the final luminal gain after directional atherectomy, since in calcific plaques stretching of the vessel wall accounted for only 9% of the luminal gain as compared to 56% in non-calcific plaques. After balloon angioplasty there was greater evidence of coronary dissections (32% v 3% after directional atherectomy, P < 0.01) and plaque fissure (60% v 0%, P < 0.01). Plaque fissure was more frequently seen in echolucent and concentric lesions, whereas dissections prevailed in echogenic and eccentric lesions. CONCLUSIONS--Intravascular ultrasound imaging may allow the assessment of acute changes in lumen and vessel wall after revascularisation procedures, and help in evaluating the potential effect of the structure and morphology of coronary lesions on the mechanism of luminal enlargement.     

Mid-term follow-up of coronary artery aneurysm after directional coronary atherectomy

Coronary artery aneurysm (CAA) occurs in 6-12% of lesions after directional coronary atherectomy (DCA). The prognosis and the optimal treatment for DCA-related CAAs have not been well known. Therefore, we reviewed the clinical course of 214 consecutive patients with DCA-related CAAs who underwent DCA in our hospital. Follow-up coronary angiography 6 months after DCA was completed in 193 patients (212 lesions) and 14 lesions with CAAs (14 patients) were detected. We evaluated these 14 lesions by repeat coronary angiography at an average of 32 months after DCA in comparison with the adjacent reference vessel. Twelve of the 14 patients have been uneventful but 2 suffered from de novo angina due to new stenotic lesion unrelated to the DCA procedures. We compared the preprocedural angiographic characteristics and periprocedural parameters between the 14 lesions with CAAs[CAA(+)group] and the 198 without CAAs [CAA(-)group], but found no significant differences. Histological examination of specimens retrieved during atherectomy demonstrated that subintimal resection was more frequent in the CAA(+)group(57%) than the CAA(-)group(31%). The diameter of the aneurysm divided by the reference diameter was significantly larger at 6 months immediately after DCA(1.71 +/- 0.21 vs 1.31 +/- 0.18, p < 0.05) but did not change subsequently (1.68 +/- 0.23). Our retrospective analysis revealed a good mid-term (an average of 32 months) prognosis for CAAs found by routine follow-up coronary angiography and also demonstrated that the depth of resection was significantly associated with aneurysm formation.     

Stenting after directional coronary atherectomy compared with directional coronary atherectomy alone and stenting alone: a serial intravascular ultrasound study.

BACKGROUND: Directional coronary atherectomy prior to stent implantation (DCA-stent) is expected to be an effective approach to reduce restenosis. The purpose of this study was to determine whether DCA-stent has advantages over DCA alone or stenting alone using serial intravascular ultrasound (IVUS). METHODS AND RESULTS: Serial (pre-, post- and follow-up) IVUS was performed in 187 native coronary lesions treated with each of the 3 strategies. External elastic membrane cross-sectional area (CSA), lumen CSA and plaque CSA were measured. Baseline characteristics were similar. Postprocedural lumen CSA was largest after DCA-stent (11.2+/-2.7 mm2) and DCA (10.8+/-2.5 mm2) than stenting alone (9.0+/-2.9 mm2) (p<0.0005). Follow-up lumen loss was similar. As a result, follow-up lumen CSA was largest after DCA-stent (DCA-stent: 9.1+/-3.4 mm2, DCA: 7.8+/-4.2 mm2, stent: 6.3+/-2.6 mm2, p<0.0005). There was a trend toward a lower rate of restenosis with DCA-stent (DCA-stent, 12.5%; DCA, 18.3%; stent, 18.8%; p=0.57). CONCLUSIONS: DCA-stent is superior to both DCA alone and stent alone in terms of the ability to gain a larger lumen as assessed by IVUS.     

Relation of deep arterial resection and coronary artery aneurysms after directional coronary atherectomy.

OBJECTIVES. The aims of this study were to document the frequency of coronary artery aneurysm formation in patients undergoing directional coronary atherectomy and to determine the relation of such aneurysms to the depth of arterial resection. BACKGROUND. Deep arterial injury is relatively frequent with the use of directional coronary atherectomy, but the potential for subsequent coronary artery aneurysm formation is unknown. METHODS. Results in a consecutive series of 64 successfully treated patients (a total of 69 lesions; mean angiographic follow-up at 5 months) treated with directional coronary atherectomy were retrospectively analyzed with use of quantitative angiographic and histologic data. RESULTS. Coronary aneurysms (ratio of dilated vessel segment to the adjacent reference segment > 1.2:1) occurred in seven patients (10%). The only significant clinical correlate of aneurysm formation was a relatively shorter duration of angina. There were no significant preprocedural angiographic predictors of aneurysms, although 6 (86%) of the 7 aneurysmal lesions arose from restenosis lesions compared with 30 (48%) of 62 lesions with no subsequent aneurysm development (p = 0.06). Histopathologic examination of 414 specimens from 68 treated lesions showed no significant difference in the occurrence of subintimal resection (media +/- adventitia) between those with and without subsequent aneurysm (29% vs. 22%). Media alone was found in 14% of specimens from lesions that later became aneurysmal versus 15% of those that did not; adventitial resection was found in 14% and 7% of specimens, respectively (p = 0.08), with relatively more adventitia per specimen from those with aneurysm (55% vs. 30% without aneurysm, p = 0.08). CONCLUSIONS. Aneurysms occur relatively frequently after directional coronary atherectomy. Although there was no statistically significant correlation with the depth of arterial resection, the evidence from this study suggests that the role of adventitial resection in the occurrence of late aneurysm development should be explored further.     

Clinical angiographic and histologic correlates of ectasia after directional coronary atherectomy.

Directional coronary atherectomy can cause ectasia (final area stenosis less than 0%), presumably due to an excision deeper than the angiographically "normal" arterial lumen. In a multicenter series in which quantitative coronary arteriography was performed after directional atherectomy in 382 lesions (372 patients), ectasia after atherectomy occurred in 50 (13%) lesions. By univariate analysis, ectasia was seen more often within the circumflex coronary artery (p = 0.008), in complex, probably thrombus-containing lesions (p = 0.015), and with higher device:artery ratios (p less than 0.001). Ectasia occurred less often in lesions within the right coronary artery (p = 0.008). Histologic analysis demonstrated adventitia or media, or both, in all patients with angiographic ectasia. Repeat angiography was performed in 188 of 271 eligible patients (69%) 6.1 +/- 2.4 months after atherectomy. Restenosis, defined as a follow-up area stenosis greater than or equal to 75%, was present in 50% of patients without procedural ectasia and in 70% of patients with marked ectasia (residual area stenosis less than -20%; p = 0.12). It is concluded that excision beyond the normal arterial lumen may occur after directional coronary atherectomy, related, in part, to angiographic and procedural features noted at the time of atherectomy. Restenosis tends to occur more often in patients with marked ectasia after coronary atherectomy.     

The mechanism of directional coronary atherectomy

An attempt was made to assess the mechanism of directional coronaryatherectomy using different methods of analysis. Quantitativecoronary angiography was used as the gold standard to assessthe immediate results of atherectomy, and a comparative quantitativeanalysis of atherectomy and balloon angioplasty was made. Todetermine whether the post-atherectomy cross-sectional areais close to a circle, we compared the area measurements obtainedby edge detection with those obtained by videodensitometry.Finally, the extent of a ‘Dotter’ effect was establishedby quantitative angiography following crossing the stenosiswith the atherectomy device. For the purpose of this study,the results of the first 113 successful atherectomy procedureswere reviewed. In matched lesions, directional atherectomy induceda greater increase in minimal luminal diameter than balloonangioplasty (1.6 mm vs 0.8 mm; P < 0.0001 However, this luminalimprovement is due to a substantial ‘Dotter’ effectinduced by the bulky atherectomy device. Following atherectomy,only a slight difference in cross-sectional area measurementsbetween edge detection and videodensitometry (mean difference:0.28 mm² was found. Histologic examination of an atherectomizedcoronary artery showed a near-circular post atherectomy areageometry. In conclusion, directional atherectomy is a very effectivedevice with a substantially better initial result than balloonangioplasty. However, insertion of this bulky device itselfcauses an important ‘Dotter’effect.     

Mechanisms and immediate and long-term results of adjunct directional coronary atherectomy after rotational atherectomy

Objectives.The purpose of this study was to confirm the mechanisms and the immediate and long-term results of rotational atherectomy and adjunct directional coronaryatherectomy.Background.Rotational atherectomy is best suited for treating calcific stenoses, but the ability of rotational atherectomy alone to optimize lumen dimensions in large vessels is limited; this is only partly improved by adjunct balloon angioplasty.Methods.We treated 165 lesions in 163 patients by use of rotational atherectomy and adjunct directional coronary atherectomy. Quantitative angiography and intravascular ultrasond were used for lesion analysis. A matched comparison with 208 lesions treated with rotational atherectomy and adjunct coronary angioplasty was performed. Patients were then followed up for at least 9 months, and target-lesion revascularization was assessed.Results.In the 61 lesions imaged sequentially, lumen area increased from 1.7 ± 0.8 (mean ± 1 SD) to 3.9 ± 1.1 mm²after rotational atherectomy, owing to a decrease in plaque plus media area from 16.8 ± 5.0 to 15.2 ± 5.2 mm²(both p < 0.0001). After adjunct directional coronary atherectomy, lumen area increased even more to 6.7 ± 2.0 mm²(vs. 5.1 ± 1.4 mm²after adjunct coronary angioplasty, p < 0.0001) as a result of both vessel expansion (18.8 ± 5.3 to 20.8 ± 5.7 mm²) and additional plaque removal (to 14.1 ± 5.0 mm², all p < 0.0001). The total arcs of calcium decreased from 207 ± 107° to 166 ± 93° after rotational atherectomy and to 145 ± 87° after directional coronary atherectomy.Overall, procedural success was 96%, and final diameter stenosis was 15 ± 17%. Target-lesion revascularization was 23%. The only independent predictor of target-lesion revascularization was a larger overall atherectomy index (84% vs. 59%, p = 0.048).Conclusions.There is a synergistic relationship between rotational atherectomy and directional coronary atherectomy in the treatment of calcific lesions. The immediate results show a high procedural success—lumen dimensions were larger and late target-lesion revascularization was lower in lesions treated with rotational atherectomy and directional coronary atherectomy than in those treated with rotational atherectomy and adjunct balloon angioplasty.     

Predictors of vessel remodeling following directional coronary atherectomy.

The purpose of this study was to clarify predictors of vessel remodeling following directional coronary atherectomy (DCA). Negative remodeling after DCA leads to restenosis. However, little is known about the predictors of the vessel remodeling. Serial IVUS was performed in 43 lesions. The vessel remodeling was defined as adaptive if vessel area at follow-up minus postprocedure vessel area was > 0 mm2, or as constrictive if < 0 mm2. Adaptive remodeling occurred in 21 (49%) lesions. Postprocedure percent plaque area was smaller in the adaptive group (32.9% +/- 5.7% vs. 45.5% +/- 8.8%; P < 0.005). At follow-up, vessel area was larger in the adaptive group. However, plaque area was similar between the two groups. As a result, lumen area was larger in the adaptive group. Multivariate analyses showed that postprocedure percent plaque area < 40% was the only predictor of adaptive remodeling (odds ratio, 6.68; P < 0.05).     

Distal embolization during directional coronary atherectomy

We report 2 cases of directional coronary atherectomy performed by using the Percu-Surge System to prevent distal embolization. A discrete amount of material was aspirated after the procedure. No clinical sequelae occurred in the immediate follow-up. These cases underline the problem of distal embolization during directional atherectomy, and the possibility to prevent it by using protection devices.     

Effects of cilostazol on late lumen loss and repeat revascularization after Palmaz-Schatz coronary stent implantation

BACKGROUND: Cilostazol is an antiplatelet agent that increases the intracellular concentration of cyclic adenosine monophosphate by inhibiting phosphodiesterase III; it has been shown to reduce neointimal hyperplasia in animal balloon injury models. METHODS: One hundred thirty patients who underwent elective stenting (Palmaz-Schatz stent) were randomly assigned to cilostazol treatment 200 mg/d (n = 65) or to ticlopidine treatment 200 mg/d (n = 65). Angiographic follow-up was performed at 6 months, and clinical follow-up was continued up to 1 year. RESULTS: One sudden death and one myocardial infarction resulting from subacute occlusion were observed in the ticlopidine group. Drug adverse effects were observed in 3 patients in the cilostazol group, as opposed to 6 patients in the ticlopidine group. In the intention-to-treat analysis, 56 patients (61 lesions) in the cilostazol group and 58 patients (58 lesions) in the ticlopidine group were assessed with quantitative coronary angiography. Late loss in the cilostazol group was smaller (0.58+/-0.52 mm vs. 1.09+/-0.65 mm, P<.0001) than in the ticlopidine group. The restenosis rate was lower in the cilostazol group than in the ticlopidine group (16% vs. 33%, P = .044). The target vessel revascularization rate at 1 year was 23% in the cilostazol group and 42% in the ticlopidine group (P =.03). CONCLUSIONS: The results of this study suggest that cilostazol may be a safe medication that is effective in preventing restenosis after stent implantation.     

Multivariate predictors of intravascular ultrasound end points after directional coronary atherectomy

Objectives. This study attempted to identify the clinical, angiographic, procedural and intravascular ultrasound predictors of directional atherectomy results assessed by intravascular ultrasound.Background. Several angiographic and intravascular ultrasound variables have been associated with the outcome of directional coronary atherectomy. No study has incorporated both modalities into a predictive model.Methods. One hundred seventy patients were analyzed using preintervention and postintervention intravascular ultrasound and quantitative angiography. Clinical and procedural variables were collected by independent chart review. Quantitative and qualitative angiographic analysis was performed by a core laboratory in blinded manner. Intravascular ultrasound was performed using a transducer-tipped catheter, rotating within a stationary imaging sheath, and withdrawn automatically at 0.5 mm/s. Clinical, procedural, angiographic and ultrasound variables were tested iin a multivariate linear regression model. Dependent ultrasound variables included postatherectomy lumen cross-sectional area and percent cross-sectional narrowing (plaque plus media/external elastic membrane cross-sectional area) and, in a subgroup of 47 patients studied using volumetric analysis, percent plaque volume removal.Results. By multivariate stepwise linear regression analysis, predictors of residual lumen cross-sectional area (correcting for reference lumen area) included arc of calcium and preatherectomy plaque plus media cross-sectional area; predictors of residual cross-sectional narrowing were arc of calcium, preatherectomy plaque plus media cross-sectional area and lesion length; and predictors of percent plaque volume removal were arc of calcium and atherectomy device size.Conclusions. The preintervention lesion arc of calcium measured by intravascular ultrasound is the most consistent predictor of the effectiveness and results of directional coronary atherectomy.