Six-month clinical and angiographic outcome of the new, less shortening Wallstent in native coronary arteries

BACKGROUND: The new, less shortening, self-expanding Wallstent is characterized by longitudinal flexibility, a protective membrane, a low profile, and a customized range of diameters (3.5 to 6.0 mm). The recent modification of the braiding angle of the Wallstent has resulted in a new device with less shortening on expansion and a concomitant reduction in radial force. We hypothesized that the enforced mechanical remodeling produced by the selection of an oversized Wallstent might result in improved accommodation of subsequent reactive intimal hyperplasia and prevention of chronic recoil of the vessel. METHODS AND RESULTS: To prove this hypothesis, we recently implanted 44 new, less shortening Wallstents in 35 native coronary arteries in 35 patients with acute or threatened closure after balloon angioplasty, according to a strategy of oversizing of Wallstent diameter and complete coverage of the lesion length. The initial and 6-month follow-up angiograms were analyzed with a computer-based quantitative coronary angiography (QCA) system. Acute gain (minimal luminal diameter [MLD] post minus MLD pre) and late loss (MLD post minus MLD at follow-up) were examined. Stent deployment was successful in 44 of 44 attempts (100%). Nominal stent diameter used was 1.40 mm larger than the maximal vessel diameter. One patient (3%) with a dilated but unstented lesion proximal to the stented segment sustained a subacute occlusion on day 1 associated with myocardial infarction. Event-free survival at 30 days after stent implantation was 97% (34 of 35 patients). Of the 34 patients eligible for 6-month angiographic follow-up, 3 who were asymptomatic declined repeat angiography. MLD (and percent diameter stenosis [% DS]) changed from 0.83 +/- 0.50 mm (72%) pre through 3.06 +/- 0.48 mm (15%) post to 2.27 +/- 0.74 mm (28%) at follow-up. Acute gain was 2.23 +/- 0.63 mm, and late loss was 0.78 +/- 0.61 mm. Angiographic restenosis ( > 50% DS) was observed in 5 of 31 patients (16%) at 6 months, all of whom underwent repeat angioplasty. Thus, the overall event-free survival at 6-month follow-up was 83% (29 of 35 patients). CONCLUSIONS: The oversized Wallstent implantation with complete coverage of the lesion length conveyed a favorable 6-month clinical and angiographic outcome. The large acute gain obtained by the Wallstent afforded greater accommodation of the subsequent late loss. The enforced mechanical remodeling by oversized new Wallstents may result in prevention of acute and chronic recoil of the vessel wall and subsequently a lower restenosis rate at follow-up.     

Differences in restenosis propensity of devices for transluminal coronary intervention. A quantitative angiographic comparison of balloon angioplasty, directional atherectomy, stent implantation and excimer laser angioplasty. CARPORT, MERCATOR, MARCATOR, PARK, and BENESTENT Trial Groups

With the increasing clinical application of new devices for percutaneous coronary revascularization, maximization of the acute angiographic result has become widely recognized as a key factor in maintained clinical and angiographic success. What is unclear, however, is whether the specific mode of action of different devices might exert an additional independent effect on late luminal renarrowing. The purpose of this study was to investigate such a difference in the degree of provocation of luminal renarrowing (or 'restenosis propensity') by different devices, among 3660 patients, who had 4342 lesions successfully treated by balloon angioplasty (n = 3797), directional coronary atherectomy (n = 200), Palmaz-Schatz stent implantation (n = 229) or excimer laser coronary angioplasty (n = 116) and who also underwent quantitative angiographic analysis pre- and post-intervention and at 6-month follow-up. To allow valid comparisons between the groups, because of significant differences in coronary vessel size (balloon angioplasty = 2.62 +/- 0.55 mm, directional coronary atherectomy = 3.28 +/- 0.62 mm, excimer laser coronary angioplasty = 2.51 +/- 0.47 mm, Palmaz-Schatz = 3.01 +/- 0.44 mm; P < 0.0001), the comparative measurements of interest selected were the 'relative loss' in luminal diameter (RLoss = loss/vessel size) to denote the restenosis process, and the 'relative lumen at follow-up' (RLfup = minimal luminal diameter at follow up/vessel size) to represent the angiographic outcome. For consistency, lesion severity pre-intervention was represented by the 'relative lumen pre' (RLpre = minimal luminal diameter pre/vessel size) and the luminal increase at intervention was measured as 'relative gain' (relative gain = gain/ vessel size). Differences in restenosis propensity between devices was evaluated by univariate and multivariate analysis. Multivariate models were constructed to determine relative loss and relative lumen at follow-up, taking account of relative lumen pre-intervention, lesion location, relative gain, vessel size and the device used. In addition, model-estimated relative loss and relative lumen at follow-up at given relative lumen pre-intervention relative gain and vessel size, were compared among the four groups. Significant differences were detected among the groups both with respect to these estimates, as well as in the degree of influence of progressively increasing relative gain, on the extent of renarrowing (relative loss) and angiographic outcome (relative lumen at follow-up), particularly at higher levels of luminal increase (relative gain). Specifically, lesions treated by balloon angioplasty or Palmaz-Schatz stent implantation (the predominantly 'dilating' interventions) were associated with more favourable angiographic profiles than directional atherectomy or excimer laser (the mainly 'debulking' interventions). Significant effects of lesion severity and location, as well as the well known influence of luminal increase on both luminal renarrowing and late angiographic outcome were also noted. These findings indicate that propensity to restenosis after apparently successful intervention is influenced not only by the degree of luminal enlargement achieved at intervention, but by the device used to achieve it. In view of the clinical implications of such findings, further evaluation in larger randomized patient populations is warranted.     

Cytochrome P450 2E1 mRNA in the rat prostate: detection and quantitation by competitive reverse transcription and polymerase chain reaction

Conventional balloon angioplasty treatment of aorto-ostial stenoses in native coronary arteries and saphenous vein grafts is associated with a low primary success rate, a high complication rate and a high incidence of restenosis. The short-term outcome of Palmaz-Schatz stent implantation in aorto-ostial lesions was compared with that of balloon angioplasty. Thirteen patients underwent stent implantation for 13 de novo lesions (four in the left main coronary trunk, two in the right coronary artery, seven in the vein graft) between January 1994 and December 1995. Fourteen patients underwent balloon angioplasty for 14 de novo lesions (five in the left main coronary trunk, four in the right coronary artery, five in the vein graft between January 1986 and April 1992. Both groups had similar clinical characteristics. Initial success was obtained in all patients in the stent group, compared with 71% of the balloon angioplasty group. Insufficient dilation was the main cause for such failure in the balloon angioplasty group. Baseline reference diameters were similar (3.40 +/- 0.65 mm in the stent group vs 3.36 +/- 0.42 mm in the balloon angioplasty group) and there was no difference in baseline minimal luminal diameter (1.41 +/- 0.74 vs 1.08 +/- 0.56 mm). Minimal luminal diameter was significantly greater in the stent group than in the balloon angioplasty group at both post-procedure and follow-up examinations (post: 3.36 +/- 0.58 vs 2.69 +/- 0.45 mm, p < 0.01; follow-up: 2.33 +/- 0.96 vs 1.52 +/- 0.68 mm, p < 0.05). There was no subacute occlusion in either group. The overall angiographic restenosis rate (> 50% stenosis) was lower in the stent group (17%) than in the balloon angioplasty group: the restenosis rates of native lesions were 0% in the stent group and 40% in the balloon angioplasty group; those of saphenous vein graft lesions were 33% in the stent group and 50% in the balloon angioplasty group. Although the number of patients was limited, these results suggest that Palmaz-Schatz stent implantation may be a safe and effective strategy for treating aorto-ostial lesions in both native coronary arteries and saphenous vein grafts.     

Excimer laser angioplasty versus balloon angioplasty in functional and total coronary occlusions

Registries of excimer laser coronary angioplasty have reported good results in the treatment of complex coronary artery disease, including total or subtotal coronary occlusions. One hundred three patients (103 lesions) with a functional or total coronary occlusion were included in a randomized trial (Amsterdam-Rotterdam [AMRO] trial, total of 308 patients), 49 patients were allocated to laser angioplasty and 54 patients to balloon angioplasty. The primary clinical end points were death, myocardial infarction, coronary bypass surgery, or repeated coronary angioplasty of the randomized segment during a 6-month follow-up period. The primary angiographic end point was the minimal lumen diameter at follow-up in relation to the baseline value (net gain), as determined by an automated contour-detection algorithm. Laser angioplasty was followed by balloon angioplasty in all procedures. The angiographic success rate was 65% in patients treated with excimer laser-assisted balloon angioplasty compared with 61% in patients treated with balloon angioplasty alone. No deaths occurred. There were no significant differences between the laser angioplasty group and the balloon angioplasty group in the incidence of myocardial infarctions (1 patient vs 3, respectively, p = 0.36), coronary bypass surgery (4 patients vs 2, respectively, p = 0.34), repeat angioplasty (10 patients vs 8, respectively, p = 0.46) or primary clinical end point (15 patients vs 12, respectively, p = 0.34). The net gain in minimal lumen diameter and restenosis rate (>50% diameter stenosis at follow-up) were 0.81 +/- 0.74 mm and 66.7%, respectively, in patients treated with laser angioplasty compared with 1.04 +/- 0.68 mm and 48.5%, respectively, in patients treated with balloon angioplasty (p = 0.59 and p = 0.15, respectively). Excimer laser-assisted balloon angioplasty demonstrated no benefit over balloon angioplasty with respect to initial and long-term clinical and angiographic outcome in the treatment of patients with functional or total coronary occlusions of >10 mm in length.     

The relation between multiple sleep latency test findings and the frequency of apneic events in REM and non-REM sleep

OBJECTIVES: The purpose of this prospective study was to evaluate the immediate results and the 6-month angiographic recurrent restenosis rate after balloon angioplasty for in-stent restenosis. BACKGROUND: Despite excellent immediate and mid-term results, 20% to 30% of patients with coronary stent implantation will present an angiographic restenosis and may require additional treatment. The optimal treatment for in-stent restenosis is still unclear. METHODS: Quantitative coronary angiography (QCA) analyses were performed before and after stent implantation, before and after balloon angioplasty for in-stent restenosis and on a 6-month systematic coronary angiogram to assess the recurrent angiographic restenosis rate. RESULTS: Balloon angioplasty was performed in 52 patients presenting in-stent restenosis. In-stent restenosis was either diffuse (> or =10 mm) inside the stent (71%) or focal (29%). Mean stent length was 16+/-7 mm. Balloon diameter of 2.98+/-0.37 mm and maximal inflation pressure of 10+/-3 atm were used for balloon angioplasty. Angiographic success rate was 100% without any complication. Acute gain was lower after balloon angioplasty for in-stent restenosis than after stent implantation: 1.19+/-0.60 mm vs. 1.75+/-0.68 mm (p=0.0002). At 6-month follow-up, 60% of patients were asymptomatic and no patient died. Eighteen patients (35%) had repeat target vessel revascularization. Angiographic restenosis rate was 54%. Recurrent restenosis rate was higher when in-stent restenosis was diffuse: 63% vs. 31% when focal, p=0.046. CONCLUSIONS: Although balloon angioplasty for in-stent restenosis can be safely and successfully performed, it leads to less immediate stenosis improvement than at time of stent implantation and carries a high recurrent angiographic restenosis rate at 6 months, in particular in diffuse in-stent restenosis lesions.     

Mechanisms of luminal enlargement and quantification of vessel wall trauma following balloon coronary angioplasty and directional atherectomy

OBJECTIVES: The purpose of this study was to assess the dual action of lumen enlargement and vessel wall damage following either balloon angioplasty or directional atherectomy, using intracoronary ultrasound, and angioscopy. BACKGROUND: Differences in the mechanisms of action of balloon angioplasty and directional atherectomy may have a significant bearing on the immediate outcome and the restenosis rate at 6 months. METHODS: A total of 36 patients were studied before and after either balloon angioplasty (n = 18) or directional atherectomy (n = 18). Ultrasound measurements included changes in lumen area, external elastic membrane area and plaque burden. In addition, the presence and extent of dissections were assessed to derive a damage score. Angioscopic assessment of the dilated or atherectomized stenotic lesions was translated into semi-quantitative dissection, thrombus and haemorrhage scores. RESULTS: Atherectomy patients had a larger angiographic vessel size compared with the angioplasty group (3.55 +/- 0.46 mm vs 3.00 +/- 0.64 mm, P < 0.05); however, minimal lumen diameter (1.18 +/- 0.96 mm vs 0.85 +/- 0.49 mm) and plaque burden (17.04 +/- 3.69 vs 15.23 +/- 4.92 mm2) measurements did not differ significantly. As a result of plaque reduction, atherectomy produced a larger increase in luminal area than the angioplasty group (5.80 +/- 1.78 mm2 vs 2.44 +/- 1.36 mm2, P < 0.0001). Lumen increase after angioplasty was the result of 'plaque compression' (50%) and wall stretching (50%). Additionally, in both groups there was indirect angioscopic evidence of thrombus 'microembolization' as an adjunctive mechanism of lumen enlargement. Angioscopy identified big flaps in six and small intimal flaps in 11 of the atherectomized patients as compared with five and 12 patients in the angioplasty group. Changes in thrombus score following both coronary interventions were identical (0.72 +/- 3.42 points atherectomy vs -0.38 +/- 3.27 points balloon angioplasty, ns). CONCLUSIONS: Lumen enlargement after directional atherectomy is mainly achieved by plaque removal (87%), whereas balloon dilation is the result of vessel wall stretching (50%) and plaque reduction (50%). Despite the fact that the luminal gain achieved by directional atherectomy is twice that achieved with balloon angioplasty, the extent of trauma induced by both techniques seems to be similar.     

Intervention and clinical aspects combined with endovascular irradiation of intimal hyperplasia of the vascular system

After implantation of stents in femoropopliteal arteries we found restenosis or occlusions by intimal hyperplasia in up to 40% especially in the hunter's channel. Repeated balloon angioplasty and prophylactic endovascular radiotherapy with a surface dose of 12 Gy in the vessel wall using an iridium 192 source in the same investigational session is a new technique to reduce or eliminate further recurrence. All 18 patients had developed recurrent stenoses or occlusions 6-8 months after original stent implantations. The patients have not redeveloped recurrent obstructions after this treatment, which up to date showed no short term or long term complications. We conclude that the encouraging results of this pilot study justify further randomized trials.     

Coronary artery restenosis after balloon angioplasty in humans is associated with circumferential coronary constriction

Therapies that inhibit intimal hyperplasia do not prevent restenosis after coronary artery balloon angioplasty, suggesting that additional mechanisms may be responsible for restenosis in humans. Using an intravascular ultrasound (Hewlett-Packard Sonos Intravascular Imaging System). 3.5F, 30-MHz (Boston Scientific) monorail imaging catheter, we studied 17 patients with clinical and angiographic restenosis at an average (mean +/- SD) of 7 +/- 6 months after balloon angioplasty (13 men age, 71 +/- 10 years; 12 left anterior descending coronary arteries, 4 right coronary arteries, and 1 left circumflex coronary artery) The lumen area (L.A), vessel wall area (VWA), and total cross-sectional area (CSA) within the external elastic lamina were measured at the restenosis site and at proximal and distal reference sites, which were defined as adjacent segments with the least amount of plaque. Consistent with coronary angiography findings, decreased LA at the restenotic site was detected in all 17 patients. The unique finding was that total CSA at the restenotic site was significantly decreased compared with both proximal and distal reference sites (10.1 +/- 2.4 versus 14.8 +/- 3.2 mm2 and 10.1 +/- 2.4 versus 13.8 +/- 3.1 mm2, respectively, P < .001), whereas VWA (intima plus media) was slightly increased at the angioplasty site compared with both proximal and distal reference sites (8.0 +/- 2.3 versus 7.6 +/- 2.3 mm2 and 8.0 +/- 2.3 versus 6.7 +/- 2.3 mm2, respectively, P = NS). Eighty-three percent of the loss in LA at the restenotic site was due to constriction of the total CSA, while the increase in VWA at the restenotic site accounted for only a 17% loss in LA. We then compared these results with the morphology of coronary artery segments in 14 patients without restenosis. These coronary artery segments had been previously treated with balloon angioplasty (7 +/- 5 months). Unlike that in restenotic lesions, the total CSA within the external elastic lamina at the sites of previous angioplasty was similar to that in distal and proximal reference sites (P = NS). Significant and consistent reduction in arterial CSA, with a minor increase in VWA, characterizes human coronary lesions that cause angiographic restenosis. These data suggest that in humans, "recoil" and/or vascular contraction with healing in response to balloon injury is a major contributor to restenosis after balloon angioplasty.     

Effect of the antioxidant Nicanartine on the proliferative and inflammatory response after experimental balloon angioplasty

BACKGROUND: Antioxidant treatment seems to reduce the development of restenosis after percutaneous transluminal angioplasty. In this study, the effect of Nicanartine, a new antioxidant drug with both antiproliferative and lipid-lowering properties, on the proliferative and inflammatory response after balloon angioplasty was investigated in a rabbit model of restenosis. METHODS: To induce pre-interventional plaques in the common carotid artery of 48 New Zealand White rabbits, electrostimulation was carried out for 28 days. After a break of 7 days, balloon angioplasty was performed in 36 animals, of which 18 received Nicanartine at a dose of 120 mg/kg body weight; the other 18 served as a control group. The vessels were excised by day 7 and 28 after balloon angioplasty and examined for intimal plaque size, macrophage content and proliferative activity. Bromodeoxyuridine labeling was used to determine proliferating cells in the dilated segment; macrophages were detected using the RAM-11 antibody. RESULTS: In the Nicanartine-treated group, immunohistological quantification 7 days after intervention showed a statistically significant (P< 0.05) reduction of both cells undergoing DNA synthesis (1.6+/-1.4% versus 3.7+/-2.2%) and intimal macrophages (0.7+/-1.2% versus 1.3+/-0.6%). Twenty-eight days after balloon angioplasty, proliferative activity in both groups was decreased to a level comparable to the non-dilated control groups. A clear trend towards smaller plaques could be seen in the Nicanartine group (0.146+/-0.077 mm2 versus 0.255+/-0.174 mm2). Total cholesterol levels did not differ significantly between the groups. CONCLUSION: Under treatment with Nicanartine a clear reduction in the proliferative and inflammatory response after balloon angioplasty was observed. Antioxidant treatment, especially with compounds having antiproliferative and lipid-lowering properties, appears to be an effective secondary preventive strategy after interventional treatment in patients with coronary artery disease.     

Are directional coronary atherectomy and Palmaz-Schatz stent more efficacious than conventional balloon angioplasty for treating de novo coronary artery lesions?

It is unclear whether new devices such as directional coronary atherectomy (DCA) or Palmaz-Schatz stent implantation improve long-term outcomes compared with conventional balloon angioplasty in patients with stable angina and de novo coronary artery lesions of type A or type B except for complete occlusive lesions investigated by the American College of Cardiology/American Heart Association task force on percutaneous transluminal coronary angioplasty. A total of 146 patients with stable angina and simple lesions were assigned to either conventional balloon angioplasty (62 patients), DCA (50 patients), or Palmaz-Schatz implantation (34 patients). The acute results and late outcomes were assessed by coronary angiography. The results of the three procedures were similar with respect to procedural success and complications. Patients who underwent stenting or DCA had a larger immediate increase in the diameter of the lumen and a larger luminal diameter immediately after the procedure than those who underwent balloon angioplasty. At six months follow-up, the patients treated by stenting continued to have a larger luminal diameter and a lower rate of restenosis than those treated with balloon angioplasty (2.30 +/- 0.66 vs 1.85 +/- 0.83 mm, p < 0.005; 5.9% vs 29%, p < 0.05) and DCA (2.30 +/- 0.66 vs 1.90 +/- 0.96 mm, p < 0.05; 5.9% vs 24%, NS). The patients treated with balloon angioplasty had a smaller late loss than those treated with DCA or Palmaz-Schatz stent. The patients treated with DCA had a larger loss index than those treated with balloon angioplasty or Palmaz-Schatz stent. Stenting was a significant factor in decreasing the rate of restenosis by logistic regression analysis, compared with balloon angioplasty. The angiographic outcomes were better in patients who received a stent than in those who received other treatments. This study suggests that even lesions stable for treatment by balloon angioplasty and DCA can also be treated with Palmaz-Schatz stents.     

Stent recoil: comparison of the Wiktor-GX coil and the Palmaz-Schatz tubular coronary stent

Wiktor-GX coil stents and Palmaz-Schatz 154A tubular stents were implanted in a consecutive series of 40 patients and 45 arteries undergoing successful primary stent placement in de novo lesions treated with single stents in order to compare the acute recoil of a coil stent to a tubular stent in native coronary arteries. Acute stent recoil was determined by measuring the difference between the maximum inflated diameter of the stent deployment balloon and the minimum lumen diameter after stent deployment. There was no difference between the two groups for reference vessel diameter, nominal balloon diameter, maximum inflated balloon diameter, maximum inflation pressure, or poststent vessel minimum lumen diameter. Acute recoil averaged 0.15 +/- 0.2 mm for the Wiktor-GX and 0.13 +/- 0.1 for the Palmaz-Schatz (P = 0.58). In this series of patients, there was no significant difference between the acute recoil of the coil stent compared to the tubular stent.     

Restenosis rates in diabetic patients: a comparison of coronary stenting and balloon angioplasty in native coronary vessels

BACKGROUND: Diabetes is a major risk factor for restenosis after coronary balloon angioplasty. Recent studies have shown that coronary stenting significantly reduces restenosis compared with balloon angioplasty alone. However, limited information is available on the effect of coronary stenting in diabetic patients. METHODS AND RESULTS: We designed this study to analyze the effect of diabetes on restenosis in patients treated with either balloon angioplasty or coronary stenting who were enrolled in a 6-month angiographic follow-up program. Three hundred consecutive patients, 19% of whom were diabetics, who underwent coronary stent implantation during a single-vessel procedure on native coronary vessels and who had 6-month angiographic follow-up constituted the study group (stent group). Three hundred consecutive patients who underwent 6-month angiographic follow-up after single-vessel conventional balloon angioplasty served as control patients (balloon group). Preprocedural, postprocedural, and follow-up angiograms were analyzed with quantitative angiography. In the balloon group, the restenosis rate was almost twofold higher in diabetic than in nondiabetic patients (63% versus 36%; P=.0002) owing to both a greater late loss (0.79+/-0.70 versus 0.41+/-0.61 mm, respectively; P<.0001) and a higher rate of late vessel occlusion (14% versus 3%, respectively; P<.001). In the stent group, restenosis rates were similar in diabetics and nondiabetics (25% versus 27%, respectively). Furthermore, in the stent group, late loss (0.77+/-0.65 versus 0.79+/-0.57 mm, respectively) and the rate of late vessel occlusion (2% versus 1%, respectively) did not differ significantly between diabetic and nondiabetic patients. CONCLUSIONS: Although diabetics have increased rates of restenosis and late vessel occlusion after simple balloon angioplasty, they have the same improved outcome with coronary stenting that has been documented in nondiabetic patients.     

Stent placement compared with balloon angioplasty for obstructed coronary bypass grafts. Saphenous Vein De Novo Trial Investigators

BACKGROUND: Treatment of stenosis in saphenous-vein grafts after coronary-artery bypass surgery is a difficult challenge. The purpose of this study was to compare the effects of stent placement with those of balloon angioplasty on clinical and angiographic outcomes in patients with obstructive disease of saphenous-vein grafts. METHODS: A total of 220 patients with new lesions in aortocoronary-venous bypass grafts were randomly assigned to placement of Palmaz-Schatz stents or standard balloon angioplasty. Coronary angiography was performed during the index procedure and six months later. RESULTS: As compared with the patients assigned to angioplasty, those assigned to stenting had a higher rate of procedural efficacy, defined as a reduction in stenosis to less than 50 percent of the vessel diameter without a major cardiac complication (92 percent vs. 69 percent, P<0.001), but they had more frequent hemorrhagic complications (17 percent vs. 5 percent, P<0.01). Patients in the stent group had a larger mean (+/-SD) increase in luminal diameter immediately after the procedure (1.92+/-0.30 mm, as compared with 1.21+/-0.37 mm in the angioplasty group; P<0.001) and a greater mean net gain in luminal diameter at six months (0.85+/-0.96 vs. 0.54+/-0.91 mm, P=0.002). Restenosis occurred in 37 percent of the patients in the stent group and in 46 percent of the patients in the angioplasty group (P=0.24). The outcome in terms of freedom from death, myocardial infarction, repeated bypass surgery, or revascularization of the target lesion was significantly better in the stent group (73 percent vs. 58 percent, P = 0.03). CONCLUSIONS: As compared with balloon angioplasty, stenting of selected venous bypass-graft lesions resulted in superior procedural outcomes, a larger gain in luminal diameter, and a reduction in major cardiac events. However, there was no significant benefit in the rate of angiographic restenosis, which was the primary end point of the study.     

Probucol decreases neointimal formation in a swine model of coronary artery balloon injury. A possible role for antioxidants in restenosis

BACKGROUND: Restenosis after percutaneous transluminal coronary angioplasty is the major limitation of the long-term success of this procedure. The process of restenosis is similar to an accelerated form of atherosclerosis. Thus, therapeutic interventions that limit the progression and initiation of atherosclerosis may be beneficial in the treatment of restenosis. One such intervention is the antioxidant drug probucol, which has demonstrated benefit in animal models of atherosclerosis. METHODS AND RESULTS: Twenty-six female domestic swine were divided into three study groups (control, n = 9; low-dose probucol, n = 9; high-dose probucol, n = 8) before oversized balloon injury of the left anterior descending and left circumflex coronary arteries. Probucol (1 g/d, low-dose group; 2 g/d, high-dose group) was administered 2 days before balloon injury and was continued until the swine were killed 2 weeks after balloon injury. Morphometric analysis of the injured arteries included the intimal area (square millimeters), maximal intimal thickness (millimeters), and residual lumen (ratio of luminal to intimal plus luminal area). Treatment with high-dose probucol significantly reduced neointimal formation compared with control animals (decreases of 36% in intimal area, P = .007; 20% in maximal intimal thickness, P = NS; and an increase of 15% in residual lumen, P = .02). CONCLUSIONS: The major finding of this study is that the antioxidant drug probucol reduces neointimal formation after oversized balloon injury in a swine model of restenosis. This suggests that active oxygen species may play a role in restenosis.     

Intestinal epithelial cell regulation of macrophage and lymphocyte interleukin 10 expression

Patients with recurrent angina after coronary artery bypass graft surgery pose a problem. Stent implantation has been advocated in an effort to avoid repeat operation and to address the limitations of balloon angioplasty. Aim of the present study was to determine the in-hospital and long-term results of stent deployment in focal, de novo lesions of vein grafts. Thirty-five focal, de novo lesions of vein grafts in 31 patients were treated with stent deployment. Twenty-four patients (77%) had three vessels, 6 (20%) two vessels and 1 (3%) single vessel disease. Saphenous vein grafts aged 9.7 +/- 4.2 years (range 1-19 years). Twenty-two lesions (63%) were located within the body of the saphenous graft, 8 (23%) at the graft/coronary artery anastomosis and 5 (14%) at the aorta/graft anastomosis. The indications for stent deployment included: suboptimal result from balloon angioplasty (defined as > or = 50% post-angioplasty residual stenosis) in 29/35 lesions (83%); post-angioplasty coronary dissection with threatening occlusion in 4/35 (11%); abrupt closure in 2/35 (6%). Patients were screened for death, myocardial infarction, bypass surgery and repeat angioplasty during in-hospital stay and after a follow-up of 12 +/- 8 months. Even-free survival curve was constructed by the Kaplan-Meier method. Stent deployment was successful in all patients. One stent was deployed in 24/35 lesions (69%), half Palmaz-Schatz stent in 6/35 (17%) and 2 or more stents in 5/35 (14%). The balloon/vessel ratio resulted of 1.0 +/- 0.1 Minimal lumen diameter increased from 0.8 +/- 0.4 to 3.8 +/- 0.6 mm, with a mean gain of 1.8 +/- 0.6 mm (range 1.8-4.0 mm). During the in-hospital period 1 patient (3.2%) died and 1 (3.2%) had a non Q wave myocardial infarction. Therefore, the clinical success rate, was 94%. During the follow-up period, 2 patients died (6.9%), 2 (6.9%) developed a non Q wave myocardial infarction, 1 (3.4%) underwent bypass surgery and 3 (10.3%) underwent repeat angioplasty. The estimated 2-year event-free survival rate (free from myocardial infarction, repeat surgery and repeat angioplasty) was 62%. In conclusion, Palmaz-Schatz stent deployment in focal, de novo vein grafts presents a high rate of procedural success, a low rate of acute complications and good long-term results.     

Comparative clinical and angiographic analysis of the initial efficacy and long-term follow-up of Wiktor stent implantation with conventional balloon angioplasty

This study was retrospectively designed to examine if the Wiktor stent, a balloon-expandable tantalum coil stent, provides a more favorable procedural and long-term clinical and angiographic outcome than does conventional coronary balloon angioplasty (POBA). From April 1995 to April 1996, we implanted 56 Wiktor stents in 46 lesions (LAD: 23, RCA: 16, CX: 7) in 42 patients (average age 53 +/- 10 years). Coronary lesions from the stent group were matched with similar lesions of another 42 POBA patients whose characteristics were identical to the Wiktor group. Revascularization indications in the Wiktor and POBA groups, respectively, were recent myocardial infarction (RMI) (45%, 40%), unstable (31%, 39%) and stable (24%, 21%) angina pectoris. 7% of the stents and 17% of the POBA balloons were less than 3 mm in diameter (p > 0.05). Procedural success was significantly greater in the Wiktor group than in the POBA group (100% vs. 92%, p < 0.05). Neither major cardiac event (death, CABG, acute myocardial infarction) nor (sub)acute occlusion was encountered in the Wiktor group during the hospitalization period and 1 month follow-up. There was 1 urgent CABG and 4 subacute occlusions in the POBA group. Control angiography at 8 months was performed in patients of both groups, of whom some were symptomatic at long-term follow-up or completely event free for 8 months. Angiographic restenosis (> 50% diameter stenosis) occurred in 25% of the Wiktor patients and in 43% of those in the POBA group (p < 0.05). For an 18 month clinical follow-up, 91% of the patients in the Wiktor group were asymptomatic and without ischemia in radionuclide imaging (RI), whereas 79% of the POBA patients were angina-free and 74% were without ischemia in the RI study. In conclusion, Wiktor stent implantation, with no major cardiac event or subacute occlusion, provides a more favorable procedural and long-term clinical and angiographic outcome than does conventional POBA.     

Recurrence and death in non-small cell lung carcinomas: a prognostic model using pathological parameters, microvessel count, and gene protein products

Optimized stent expansion by high-pressure inflations of oversized balloons has initially been derived from experience obtained with the Palmaz-Schatz stent, whereas there is little experience with this strategy in the Wallstent. By using this approach with quantitative coronary angiographic guidance, 20 Wallstents and 20 Palmaz-Schatz stents were implanted in 34 patients and consecutively examined by conventional two-dimensional (2D) intracoronary ultrasound (ICUS) and three-dimensional (3D) ICUS on the basis of the application of a pattern recognition algorithm. Ultrasound criteria of adequate stent expansion were defined as a complete apposition of the stent to the vessel wall, a stent symmetry index (SSI = minimum/maximum lumen diameter) > or = O.7, and a stent-reference lumen area ratio (SRR = Minimum intrastent lumen area/Average of proximal and distal reference lumen area) > or = O.8. In all cases a smooth angiographic lumen and a negative diameter stenosis, on the basis of a distal reference, was achieved. For the Wallstents ICUS showed a higher SSI (2D, 0.95 +/- 0.04 vs 0.85 +/- 0.09; p < 0.001; 3D, 0.90 +/- 0.09 vs 0.82 +/- 0.11, p < 0.05) and a lower SRR (2D, 0.66 +/- 0.12 vs 0.81 +/- 0.13, p < 0.005; 3D, 0.63 +/- 0.14 vs 0.74 +/- 0.15, p < 0.05) than for the Palmaz-Schatz stents. Ninety percent of failure in meeting these criteria resulted from a low SRR. The incidence of incomplete stent apposition (one in both stents) or SSI <0.7 was low and generally associated with an SRR <0.8. The Wallstents met the ICUS criteria less often (2D, 2(1O%) vs 10(50%), p < 0.01; 3D, 3(15%) vs 9(45%), p < 0.05), were significantly longer (35.1 +/- 7.7 mm and 14.3 +/- 3.3 mm, p < 0.0001), and generally demonstrated a larger vessel tapering, measured as proximal minus distal ICUS reference lumen area (1.33 +/- 2.91 mm2 vs 0.44 +/- 1.97 mm(2), not significant). Wallstents meeting the ICUS criteria, however, showed less vessel tapering (0.18 +/- 1.64 mm(2)). Thus optimized stent expansion was followed by excellent angiographic results for both Palmaz-Schatz and Wallstent. Although angiographic results and visual assessment of the ICUS examination suggested a good outcome, few Wallstents met the ICUS criteria in contrast to the Palmaz-Schatz stents. The low value of the SRR in the Wallstents is likely to be caused by vessel tapering, suggesting that this criterion may be unsuitable in assessing the adequacy of the expansion of relatively long stents such as the Wallstent.     

Coronary-artery stenting compared with balloon angioplasty for restenosis after initial balloon angioplasty. Restenosis Stent Study Group

BACKGROUND: Intracoronary stenting reduces the rate of restenosis after angioplasty in patients with new coronary lesions. We conducted a prospective, randomized, multicenter study to determine whether intracoronary stenting, as compared with standard balloon angioplasty, reduces the recurrence of luminal narrowing in restenotic lesions. METHODS: A total of 383 patients who had undergone at least one balloon angioplasty and who had clinical and angiographic evidence of restenosis after the procedure were randomly assigned to undergo standard balloon angioplasty (192 patients) or intracoronary stenting with a Palmaz-Schatz stent (191 patients). The primary end point was angiographic evidence of restenosis (defined as stenosis of more than 50 percent of the luminal diameter) at six months. The secondary end points were death, Q-wave myocardial infarction, bypass surgery, and revascularization of the target vessel. RESULTS: The rate of restenosis was significantly higher in the angioplasty group than in the stent group (32 percent as compared with 18 percent, P= 0.03). Revascularization of the target vessel at six months was required in 27 percent of the angioplasty group but in only 10 percent of the stent group (P=0.001). This difference resulted from a smaller mean (+/-SD) minimal luminal diameter in the angioplasty group (1.85+/-0.56 mm) than in the stent group (2.04+/-0.66 mm), with a mean difference of 0.19 mm (P=0.01) at follow-up. Subacute thrombosis occurred in 0.6 percent of the angioplasty group and in 3.9 percent of the stent group. The rate of event-free survival at 250 days was 72 percent in the angioplasty group and 84 percent in the stent group (P=0.04). CONCLUSIONS: Elective coronary stenting was effective in the treatment of restenosis after balloon angioplasty. Stenting resulted in a lower rate of recurrent stenosis despite a higher incidence of subacute thrombosis.     

The oxidative metabolism of catecholamines in the brain: a review

The EBI (BARD-XT, C.R. Bard, Murray Hill, NJ) stent is a new radiopaque balloon expandable coronary stent with high resistance to external radial forces. It does not shorten significantly with expansion and allows stent implantation in bifurcation lesions. A total of 28 EBI stents were implanted in 23 lesions in 21 patients. Indications for stent implantation were acute closure in 1, threatened closure in 15, and electively in 7 lesions. In 2 cases, the lesion involved a bifurcation where a stent was implanted in both vessels. All patients received aspirin and ticlopidine. No anticoagulant therapy was given. The stenting procedure was successful in 22 of 23 lesions. No complications occurred with the exception of 1 patient with a thrombotic reocclusion within 1 hr after stent implantation and 1 patient with a temporary occlusion of a side branch. The mean minimal luminal diameter (MLD) increased from 0.74+/-0.46 mm before balloon dilatation to 1.27+/-0.62 mm before stent implantation and 2.32+/-0.57 mm after stent implantation. Percent stenosis decreased from 71+/-19% before angioplasty to 46+/-25% after angioplasty to 5+/-8% after stent implantation. MLD at the time of follow-up angiography after 4 months was 1.98+/-0.77 mm and percent stenosis was 26+/-21%. Restenosis of more than 50% occurred in 2 lesions. In these lesions, a second percutaneous transluminal coronary angioplasty was performed. Advantages of this stent are its flexibility together with an acceptable radial strength as well as enabling radiopacity without obscuring the arterial lumen. Stenting of bifurcation lesions is possible.     

Mechanical debulking versus balloon angioplasty for the treatment of true bifurcation lesions

OBJECTIVES: The purpose of this study was to compare the immediate angiographic and long-term results of debulking versus balloon angioplasty for treatment of true bifurcation lesions. BACKGROUND: Previous studies have shown true bifurcation lesions to be a high risk morphological subset for percutaneous transluminal coronary angioplasty (PTCA). Although atherectomy devices have been used to treat bifurcation lesions, no studies have compared the outcomes of these alternative treatment modalities. METHODS: Between January 1992 and May 1997, we treated 70 consecutive patients with true bifurcation lesions (defined as a greater than 50% stenosis in both the parent vessel and contiguous side branch) with conventional PTCA (n = 30) or debulking (with rotational or directional atherectomy) plus adjunctive PTCA (n = 40). Paired angiograms were analyzed by quantitative angiography, and clinical follow-up was obtained in all patients. RESULTS: Acute procedural success was 73% in the PTCA group and 97% in the debulking group (p = 0.01). Major in-hospital complications occurred in two patients in the PTCA group and one in the debulking group. Treatment with atherectomy plus PTCA resulted in lower postprocedure residual stenoses than PTCA alone (16+/-15% vs. 33+/-17% in the parent vessel, and 6+/-15% vs. 39+/-22% in the side branch; p < 0.001 for both comparisons). At 1 year follow-up, the incidence of target vessel revascularization (TVR) was 53% in the PTCA group as compared with 28% in the debulking group (p = 0.05). Independent predictors of the need for repeat TVR were side branch diameter >2.3 mm, longer lesion lengths, and treatment with PTCA alone. CONCLUSIONS: For the treatment of true bifurcation lesions, atherectomy with adjunctive PTCA is safe, improves acute angiographic results, and decreases target vessel revascularization compared to PTCA alone. The benefits of debulking for bifurcation lesions were especially seen in lesions involving large side branches.