Comparison of intracoronary ultrasound expansion parameters in coronary stents implanted with or without balloon predilatation. A randomized intravascular ultrasound study

INTRODUCTION AND OBJECTIVES: Coronary stenting without balloon predilatation is a safe technique associated with similar clinical results and lower costs, use of contrast and exposure to radiation in comparison to stenting with predilatation. After direct stenting, expansion may be reduced if the stenotic lesion was not predilatated. This study compared a). stent expansion with and without balloon predilatation (direct stenting), observed by intracoronary ultrasound, and b). angiographic results after 6 months and 1 year with the two implantation techniques. PATIENTS AND METHOD: 100 consecutive lesions eligible for direct stenting were randomized to stent implantation with or without balloon predilatation. Only 相似文献   

Direct coronary stenting versus stenting with balloon pre-dilation: immediate and follow-up results of a multicentre, prospective, randomized study. The DISCO trial. DIrect Stenting of COronary Arteries.

AIMS: To assess the safety of direct coronary stenting, its influence on costs, duration of the procedure, radiation exposure, clinical outcome and angiographic restenosis. METHODS AND RESULTS: We randomized 416 patients (446 lesions) to direct stent implant or stent implant following balloon pre-dilation. Patients >75 years old, heavily calcified lesions, bifurcations, total occlusions, left main lesions and very tortuous vessels were excluded. Direct stenting was successful in 217/224 lesions (96.8%). No single loss or embolization of the stent occurred. All stents in the group with pre-dilation were effectively deployed. The immediate post-procedure angiographic results were similar with both techniques. Fluoroscopy and procedural time were significantly lower in direct stenting (6.4+/-0.3 and 21+/-0.9 min) than in pre-dilated stenting (9.1+/-0.4 and 27.5+/-1.1 min) (P>0.001). Major adverse cardiac events during hospitalization were one in direct and four in pre-dilated stenting (P=0.05) but there were no significant differences at follow-ups at 1, 6 and 12 months between the two groups. Angiographic reevaluation at 6 months was performed in 94% of the cases. Restenosis rate was 16.5% in direct stenting and 14.3% in pre-dilated stenting (P=ns). CONCLUSIONS: Direct stenting is as safe as pre-dilated stenting in selected coronary lesions. Acute angiographic results are similar but procedural costs, duration of the procedure and radiation exposure are lower in direct stenting. Overall success rate, mid-term clinical outcome and restenosis are similar with both techniques.     

A direct stent without predilatation. Our experience in 300 lesions]

INTRODUCTION: The stent alone technique, direct stenting without predilatation, aims to reduce cost and procedural time. Other potential benefits are the avoidance of abrupt vessel closure after balloon angioplasty and lessening of the restenosis rate due to the reduced arterial injury. We present our experience with this therapeutic approach in a long series of patients. PATIENTS AND METHODS: 230 patients referred to our unit were included with 300 non-occlusive stenotic lesions without excessive tortuosity, calcification, length or angulation and with a reference vessel diameter > or = 2.5 mm. In these patients stent implantation without predilatation was attempted. The immediate angiographic results and procedural related complications were evaluated. RESULTS: The stent alone technique succeeded in 256 (85%) among the 300 lesions treated. In 43 (14.3%) lesions predilatation was required and in one case the stent could not be positioned. A new dilatation after deployment was required due to suboptimal stent expansion in 27/256 (10.5%) lesions. Stent embolization occurred in 5 patients, 4 stents were retrieved and there were no clinical sequelae. The best results were obtained in non-subtotal and non-bifurcated lesions type A or B1 without moderate calcification, tortuosity or angulation. CONCLUSIONS: Direct stenting is feasible in a large number of patients with a high success rate after an appropriate selection. The most optimal lesions to be treated with this technique are < or = 90% stenotic non-bifurcated lesions type A or B1 without moderate calcification, tortuosity or angulation.     

Effectiveness of "direct" stenting without balloon predilatation (from the Multilink Tetra Randomised European Direct Stent Study [TRENDS])

The purpose of the TRENDS trial was to assess the safety, efficacy, and cost effectiveness of a no-predilatation ("direct") stenting strategy in the treatment of de novo native coronary artery lesions using the Multilink Tetra stent system. In this multicenter, prospective clinical trial, 1,000 patients were randomized (1:1) to receive a Multilink Tetra stent with or without balloon predilatation. The primary outcome measurement was major adverse cardiac events (MACEs) at 30 days; secondary end points included resource utilization (including procedural duration, equipment use, and length of hospital stay), MACEs, and angiographic binary restenosis at 180 days. In the predilatation group, 587 stents were implanted in 499 patients; in the direct group, 579 stents were implanted in 501 patients. In the direct group, stents in 31 lesions (5.7%) required predilatation and multivariate analysis identified calcification (odds ratio 5.81), angulation (odds ratio 5.34), and preprocedural minimal lumen diameter (odds ratio 0.09) as direct stenting failure. MACEs at 30 days were similar in the 2 groups, with 19 (3.8%) in the predilatation group and 13 (2.6%) in the direct group (p = NS). Resource utilization favored the direct strategy, with decreases in balloon use, contrast media, and procedure time, but a larger number of guiding catheters was used. The 180-day MACE rate of 9.8% in the direct group was not significantly less than the rate of 10.8% in the predilatation group (p = NS). Quantitative angiographic follow-up at 6 months demonstrated in-stent binary restenotic rates of 11.4% in the predilatation group (late loss 0.88 +/- 0.53 mm) and 12.3% in the direct group (late loss 0.82 +/- 0.51 mm, p = NS) and in-segment restenosis rates of 12.2% and 13.4%, respectively (p = NS). In conclusion, a direct stenting strategy with the Multilink Tetra stent was feasible and safe in 94% of lesions and associated with lower resource utilization compared with a predilatation approach. Direct stenting was not associated with significantly lower MACE and target lesion revascularization rates and had no effect on late angiographic follow-up, with similar late loss reflecting an identical biologic response to bare metal stent placement.     

Six-month angiographic follow-up after intravascular ultrasound-guided stenting of infarct-related artery: comparison with non-infarct-related artery

BACKGROUND: Compared with balloon angioplasty, stenting has been established as an effective treatment modality to reduce restenosis in patients with acute myocardial infarction. However, the immediate results that predict favorable long-term outcomes in the acute infarct stenting are unknown. Therefore, we evaluated long-term outcomes of stenting for infarct-related artery (IRA) lesions by using intravascular ultrasound (IVUS) compared with that of stenting for non-IRA lesions. METHODS: IVUS-guided coronary stenting was successfully performed in 510 native coronary lesions (105 IRA vs 405 non-IRA). A 6-month follow-up angiogram was performed in 419 (82.2%) lesions: 87 (82.9%) IRA lesions and 332 (82.0%) non-IRA lesions. Coronary stenting on the IRA lesions was successfully performed within 7 to 10 days after onset of infarction in 42 patients and within 12 hours in 45 patients. Results were evaluated by clinical, angiographic, and IVUS methods. RESULTS: There were no significant differences in clinical and angiographic variables between the two groups. IVUS variables including reference vessel area and minimal stent area were also similar between the two groups. There was no significant difference in angiographic restenosis rate between the two groups in cases of minimal stent area > or = 7 mm(2): 12.8% (6 of 47) in IRA versus 19.1% (33 of 173) in non-IRA lesions (P = .315). However, the angiographic restenosis rate in cases of minimal stent area <7 mm(2) was 50% (20 of 40) in IRA lesions versus 31.5% (50 of 159) in non-IRA lesions (P = .028). CONCLUSIONS: Angiographic restenosis is significantly higher in stenting for IRA lesions compared with that for non-IRA lesions in cases of minimal stent area < 7 mm(2).     

Intravascular ultrasonic predictors of angiographic restenosis after long coronary stenting

The intravascular ultrasound (IVUS) criteria for stent optimization have not been determined in stenting long lesions. We evaluated the predictors of angiographic restenosis and compared it with stent lumen cross-sectional area (CSA) and stent length between short (stent length <20 mm) and long (> or =20 mm) coronary stenting. IVUS-guided coronary stenting was successfully performed in 285 consecutive patients with 304 native coronary lesions. Six-month follow-up angiogram was performed in 236 patients (82.8%) with 246 lesions (80.9%). Results were evaluated using conventional (clinical, angiographic, and IVUS) methods. The overall angiographic restenosis rate was 22.8% (56 of 246 lesions) (short stent 17.6% vs. long stent 32.2%, p = 0.009). Using multivariate logistic regression analysis, the independent predictors of angiographic restenosis were the IVUS stent lumen CSA (odds ratio 1.51, 95% confidence intervals 1.18 to 1.92, p = 0.001) and stent length (odds ratio 0.95, 95% confidence intervals 0.91 to 1.00, p = 0.039). The angiographic restenosis rate was 54.8% for stent lumen CSA of <5.0 mm2 (short stent 37.5% vs. long stent 73.3%, p = 0.049), 27.4% for CSA between 5.0 and 7.0 mm2 (short stent 24.1% vs. long stent 31.7%, p = 0.409), 10.5% for CSA between 7.0 and 9.0 mm2 (short stent 10.0% vs. long stent 12.5%, p = 0.772), and 11.4% for stent lumen CSA of > or =9.0 mm2 (short stent 10.4% vs. long stent 13.3%, p = 0.767) (p = 0.001). Compared with short coronary stenting, long coronary stenting is effective treatment modality to cover long lesions with comparable long-term clinical outcomes in cases of stent lumen CSA of > or =7.0 mm2. Regardless of the stent length, the most important factor determining angiographic restenosis was the IVUS stent lumen CSA in relatively large coronary artery lesions.     

Immediate and late clinical and angiographic outcomes after GFX coronary stenting: Is high-pressure balloon dilatation necessary?

BACKGROUND: The GFX stent is a balloon-expandable stent made of sinusoidal element of stainless steel. The adjunct high-pressure balloon dilatations were usually recommended in routine stenting procedure. HYPOTHESIS: The aim of this study was to evaluate the immediate and long-term clinical and angiographic outcomes and to investigate the necessity of high-pressure balloon dilatation during GFX stenting. METHODS: In all, 172 consecutive patients underwent single 12 or 18 mm GFX stent implantation in 188 native coronary lesions. Two types of stenting technique were used: (1) stent size of a final stent-to-artery ratio of 1:1 (inflation pressure > 10 atm, high-pressure group), and (2) stent size of 0.5 mm bigger than reference vessel (inflation pressure < or = 10 atm, low-pressure group). The adjunct high-pressure balloon dilatations were performed only in cases of suboptimal results. RESULTS: The adjunct high-pressure balloon dilatation was required in 11 of 83 lesions (13%) in the high-pressure group and in 7 of 105 lesions (7%) in the low-pressure group (p = 0.203). Procedural success rate was 100%. There were no significant differences of in-hospital and long-term clinical events between the two groups. The overall angiographic restenosis rate was 17.7%; 18.4% in the high-pressure group and 17.1% in the low-pressure group (p = 0.991). CONCLUSIONS: The GFX stent is a safe and effective device with a high procedural success rate and favorable late clinical outcome for treatment of native coronary artery disease. Further randomized trials may be needed to compare stenting techniques in GFX stent implantation.     

Preliminary experience with intravascular ultrasound guided Palmaz-Schatz coronary stenting: the acute and short-term results on a consecutive series of patients

The purpose of this study was to prospectively test the hypothesis that systemic anticoagulation is not needed following coronary stenting when adequate stent expansion is achieved and documented and other flow limitations eliminated. Intravascular ultrasound (IVUS) was used to confirm adequate stent expansion, which was defined as good plaque compression together with the achievement of an intrastent lumen cross-sectional area (CSA) that was greater than 40% of the average reference vessel CSA. In this prospective study, Palmaz-Schatz coronary stenting was performed on 343 lesions in 263 consecutive patients. Primary stenting was successful in 254 patients (96.6%) and 332 lesions (96.8%). All patients with successful primary stenting underwent IVUS imaging except nine patients (13 lesions) that did not have an IVUS evaluation for technical reasons and three patients (4 lesions) in which IVUS was unsuccessful. The initial IVUS performed after achieving an acceptable angiographic result revealed inadequate stent expansion in 191 patients (79%) and 244 lesions (77%). After further dilatation, final adequate stent expansion was accomplished in 230 patients and 301 lesions. These patients were treated with Ticlopidine 250 mg twice per day for 2 months and did not receive postprocedure anticoagulation. There was one acute stent thrombosis (0.3%) that occurred in a lesion with slow flow and an inadequately expanded stent. There was no subacute stent thrombosis and no bleeding or vascular complications. We conclude that when adequate stent expansion is achieved and confirmed and other flow limiting lesions eliminated, that systemic anticoagulation after the stent procedure is not necessary.     

Comparison of PRE-dilatation vs direct stenting in coronary treatment using the Medtronic AVE S670 Coronary Stent System (the PREDICT trial).

Current stent delivery systems make primary stenting (stent placement without predilatation) possible, but few controlled trials have been performed to evaluate the success, safety, cost saving, and potential benefit of this approach in reducing late restenosis. The Comparison of PRE-Dilatation Versus Direct Stenting In Coronary Treatment using the Medtronic AVE S670 Coronary Stent System trial was a 399-patient study comparing results with the Medtronic-AVE S670 stent to objective performance criteria based on prior approved stents, with subrandomization to direct stenting versus stenting after balloon predilatation. Overall, results with the S670 stent showed excellent success and safety, with delivery success of 99%, a 14-day adverse event rate of 6.8% (including 6.5% non–Q-wave myocardial infarction), and favorable angiographic (20%) and clinical (12%) restenosis rates. Direct stenting was successful in 92% of cases, with a 99.5% secondary success rate including additional pretreatment of initially unsuccessful direct-stenting attempts, and no increase in complications. There were modest (10%) savings in fluoroscopy time, contrast use, and a decrease in angioplasty balloon use (0.6 vs 1.3 balloons/case), but no reduction in clinical or angiographic restenosis. Patients treated later in the study, with a device that had less balloon extension beyond the edges of the stent, had slightly lower angiographic restenosis rates (19% vs 23%). In conclusion, the S670 stent showed excellent overall performance. Although direct stenting was safe and highly successful, it offered only modest cost savings, and no reduction in late restenosis compared with stenting after predilatation.     

Additional luminal area gain by intravascular ultrasound guidance after coronary stent implantation with high inflation pressure

Aims: Studies by intravascular ultrasound demonstrated inadequate expansion in a large number of stents, which lead to the increase of inflation pressures for stenting. The present study examined whether routine use of high-pressure inflation would be sufficient for an optimum stent expansion without sonographic guidance. Methods and results: Two types of single coronary stents (Palmaz-Schatz in 54, and Wiktor in 25) were implanted with inflation pressures of 16–20 atm in 79 nonocclusive coronary lesions. IVUS before stenting was used in 78% to select the adequate stent size. Intravascular ultrasound after stenting was used to assess the minimum stent area and diameter, the reference areas, and the strut apposition to the vessel wall. The difference between the area of the expanding balloon and the stent area was calculated as the luminal deficit of the stent. Completeness of stent expansion required full strut apposition and lesion coverage, and a minimum stent area that was larger than the distal reference, and larger than 60% of the proximal reference. Intravascular ultrasound before stenting lead to an increase of the stent size in 47%. After high-pressure expansion, even with the optimized balloon size, 8% of stents had struts protruding into the lumen. The stent area (6.87 ± 1.93 mm²) was significantly smaller than both the proximal (9.59 ± 2.91 mm²; p<0.001) and distal reference area (8.23 ± 3.03 mm²; p<0.001). The criteria for complete expansion were met in 48%. The expansion with a larger high-pressure balloon in 28 stents lead to an increase of the stent area by 19% (8.19 ± 2.24; p<0.001), and full stent apposition in all cases. The criteria of stent expansion were met in 82%. A wide range of the luminal deficit upto 48% was observed, which was not related to sonographic lesion characteristics, except in lesions with complete circumferential calcifications. The different stent designs were characterized by a slightly lower luminal deficit in slotted-tube stents (23 ± 13% vs. 28 ± 12%; p=0.11) and a better index of stent symmetry as compared with the coil stent (0.87 ± 0.08 vs. 0.82 ± 0.09; p<0.05). Conclusion: Routine use of high-pressure stent expansion did not lead to a sufficient stent expansion, even when the initial stent size had been guided by intravascular ultrasound. Further stent dilatation with larger balloons under ultrasound guidance would be required to optimize the luminal area gain.     

Nonselected use of direct coronary stenting. The DISCO 2 trial

INTRODUCTION AND OBJECTIVES: Direct coronary stenting yields immediate long-term clinical results similar to those obtained with balloon predilation, with the advantage of lower costs and procedural times. Until now, direct stenting has been attempted only for selected lesions, so that the potential scope of its use in everyday practice remains unknown. The DISCO 2 trial was designed to identify the number and type of lesions that could be safely treated by direct stenting. Patients and method. 1,269 lesions (886 patients) were treated consecutively in 7 different hospitals. Direct stenting was attempted in all cases, except for total chronic occlusions, severe tortuosity or calcification of the vessel, lesions in the sinus ostium, or bifurcated lesions and vessel diameter < 2.4 mm. If the procedure failed, the stent was recovered and the lesion dilated with a balloon before a second attempt at stenting. RESULTS: Direct stenting was attempted in 585 lesions (54.9% of all electively implanted stents and 46.1% of all angioplasties). This was successful in 553 (94.6%) and failed in 32 (5.4%). In 30 of these latter patients a stent was implanted after predilation. Predictors of failure were tortuosity, location in the nonproximal right coronary artery, age > 65 years and type B2 or C lesion. After 6 months of follow-up the total incidence of major adverse cardiovascular events in patients treated with direct stenting was 6.2%, with a target lesion revascularization rate of 4.45%. CONCLUSIONS: In a mostly nonselected sample of coronary lesions, direct stenting was as safe as stenting with predilation. More than half of all elective stenting procedures can be attempted safely without balloon predilation. Greater need for predilation was associated with tortuosity, nonproximal right coronary artery location, older age and lesion complexity (B2, C). The 6-month clinical outcome was excellent, with a low rate of repeat revascularization.     

Direct coronary stenting versus predilatation followed by stent placement

Direct stenting without antecedent dilatation may reduce procedural time, costs, and radiation exposure, and may result in less vessel injury. The purpose of this investigation was to compare immediate and long-term clinical and angiographic outcomes of direct stenting with stent placement after initial balloon dilation. Three hundred thirty-five symptomatic patients with single or multiple coronary lesions (diameter reduction 60% to 95%) of < or =30 mm length and with a vessel diameter of 2.5 to 4.0 mm were randomized either to direct stenting (group A, n = 171) or stenting after predilation (group B, n = 164). Patients with vessels with excessive calcification, severe proximal tortuosity, or occlusion were excluded. All patients were asked to return for routine repeat angiography at 6 months, irrespective of symptoms. Feasibility of direct stenting was 95% in group A, with 5% requiring crossover to predilation. Successful stent placement after predilation was performed in all 164 patients in group B. Direct stenting was associated with less procedural duration (group A 42.1 +/- 18.7 minutes vs group B 51.5 +/- 23.8 minutes, p = 0.004), radiation exposure time (group A 10.3 +/- 7.7 minutes vs group B 12.5 +/- 6.4 minutes, p = 0.002), amount of contrast dye used (group A 163 +/- 69 ml vs group B 197 +/- 84 ml, p <0.0001), and lower procedural costs (group A 845 +/- 167 vs group B 1,064 +/- 175, p <0.0001). Immediate angiographic results and in-hospital clinical outcomes (death, Q-wave myocardial infarction, repeat revascularization) were not significantly different between both strategies. However, at 6-month follow-up, direct stenting was associated with a lower angiographic restenosis (group A 20% vs group B 31%, p = 0.048) and target lesion revascularization rates (group A 18% vs group B 28%; p = 0.03). This study demonstrates the feasibility, safety, and outcomes of direct stenting in eligible coronary lesions. In appropriately selected cases, direct stenting has a lower rate of angiographic restenosis up to 6 months after the procedure, resulting in fewer coronary reinterventions compared with the conventional strategy of stenting with antecedent dilatation.     

Stenting of Nonacute Total Coronary Occlusions: Predictors of Late Angiographic Outcome

Objectives. This study was designed to determine and assess factors predictive of the intermediate-term outcome of stenting of nonacute total coronary occlusions.Background. Balloon angioplasty of recanalized coronary occlusions is associated with a combined restenosis/reocclusion rate of up to 65%. Adjunctive stenting holds the potential to reduce this rate significantly. However, variables affecting the late angiographic outcome of coronary stenting in the setting of a total occlusion have not been elucidated sufficiently.Methods. Coronary stenting was performed in 143 consecutive patients with a nonacute total occlusion; 120 of these patients (84%), with a total of 121 occlusions, underwent repeat angiography within 6 months and comprised the study group. High pressure stent implantation aimed to cover the site of the occlusion as well as adjacent diameter stenoses ≥70% and all possibly induced dissections. Pertinent angiographic and procedural variables obtained at the time of the intervention were entered into a multivariate logistic regression analysis model to assess their influence on the angiographic outcome at follow-up.Results. Mean preinterventional reference lumen diameter for the 121 vessels was 2.99 ± 0.53 mm (mean ± SD); occlusion length ranged from 4 to 44 mm (median of 7.7). After balloon angioplasty, dissections were found in 80% of patients. Lesions were covered with stents a median of 16 mm in length (range 8 to 53). The minimal lumen diameter (MLD) achieved after stenting was 2.89 ± 0.48 mm. After a median follow-up period of 4.5 months, mean MLD was assessed at 1.91 ± 0.90 mm, corresponding to a loss index of 0.34 ± 0.31. There were 27 vessels with a nonocclusive restenosis ≥50% and 8 with a reocclusion, for a combined restenosis/reocclusion rate of 29%. Factors found to adversely influence angiographic outcome were a post-stenting MLD ≤2.54 mm, a stented vessel segment length >16 mm, a balloon/vessel diameter ratio for final stent expansion ≤1.00 and the presence of a dissection after balloon angioplasty.Conclusions. Compared with previous reports on stand-alone balloon angioplasty, stenting of nonacute total coronary occlusions lowers the 6-month restenosis/reocclusion rate to ∼30%. The late procedural outcome is independently and statistically significantly influenced by the MLD after stenting, the length of the stented vessel segment, the balloon/vessel diameter ratio for final stent expansion and the incidence of dissections after balloon angioplasty.     

Conventional versus direct stenting in AMI: effect on immediate coronary blood flow

There are no data regarding the potential benefits of direct stenting in the setting of AMI. The aim of this study was to evaluate the impact of direct stenting on the angiographic results and compare it to conventional stenting performed in the setting of AMI. We reviewed our institutional interventional database and identified 44 patients who had undergone stenting in the setting of AMI (29 primary and 15 rescue angioplasty). Patients were then divided into two groups; group A consisted of patients who had undergone conventional stenting (23 patients) and group B those who had undergone direct stenting (21 patients). Angiographic success was defined as TIMI flow grade 2. The baseline TIMI 0-1 flow was higher in group A compared to group B (74% vs. 24%; p < 0.05). TIMI flow rates before stenting (after balloon predilation in group A and after guidewire crossing in group B) and angiographic success (TIMI flow 2) after stenting were similar in both groups (p > 0.05). However, the final TIMI 3 flow were significantly better in group B after stenting (65% vs. 95%; p < 0.05). Although there was no no re-flow in group B, three patients in group A had no re-flow after balloon predilatation of lesions with baseline TIMI 2 flow. There was a statistical tendency to a higher TIMI 3 flow in patients treated with direct stenting in the setting of AMI. Direct stenting strategy in thrombus containing lesions seems to be a safe and feasible approach in avoiding no re-flow.     

Role of Coronary Artery Lumen Enlargement in Improving Coronary Blood Flow After Balloon Angioplasty and Stenting: A Combined Intravascular Ultrasound Doppler Flow and Imaging Study

Objectives. This study sought to examine the mechanism of increasing coronary flow reserve after balloon angioplasty and stenting.

Background. Coronary vasodilatory reserve (CVR) does not improve after percutaneous transluminal coronary angioplasty in ≥50% of patients, postulated to be due to impaired microvascular circulation or inadequate lumen expansion despite adequate angiographic results.

Methods. To demonstrate the role of coronary lumen expansion, serial coronary flow velocity (0.014-in. Doppler guide wire) was measured in 42 patients before and after balloon angioplasty and again after stent placement. A subset (n = 17) also underwent intravascular ultrasound (IVUS) imaging of the target sites after angioplasty and stenting. CVR (velocity) was computed as the ratio of adenosine-induced maximal hyperemic to basal average peak velocity.

Results. The percent diameter stenosis decreased from (mean ± SD) 84 ± 13% to 37 ± 18% after angioplasty and to 8 ± 8% after stenting (both p < 0.05). CVR was minimally changed from 1.70 ± 0.79 at baseline to 1.89 ± 0.56 (p = NS) after angioplasty but increased to 2.49 ± 0.68 after stent placement (p < 0.01 vs. before and after angioplasty). IVUS lumen cross-sectional area was significantly larger after stenting than after angioplasty (8.39 ± 2.09 vs. 5.10 ± 2.03 mm², p < 0.05). Anatomic variables were related to increasing coronary flow velocity reserve (CVR vs. IVUS lumen area: r = 0.47, p < 0.005; CVR vs. quantitative coronary angiographic percent area stenosis: r = 0.58, p < 0.0001).

Conclusions. In most cases, increases in CVR were associated with increases in coronary lumen cross-sectional area. These data suggest that impaired CVR after angioplasty is often related to the degree of residual narrowing, which at times may not be appreciated by angiography. A physiologically complemented approach to balloon angioplasty may improve procedural outcome.

(J Am Coll Cardiol 1997;29:1520–7)     

Comparison of PRE-dilatation vs Direct stenting In Coronary Treatment using the Medtronic AVE S670 Coronary Stent System (the PREDICT trial)

Current stent delivery systems make primary stenting (stent placement without predilatation) possible, but few controlled trials have been performed to evaluate the success, safety, cost saving, and potential benefit of this approach in reducing late restenosis. The Comparison of PRE-Dilatation Versus Direct Stenting In Coronary Treatment using the Medtronic AVE S670 Coronary Stent System trial was a 399-patient study comparing results with the Medtronic-AVE S670 stent to objective performance criteria based on prior approved stents, with subrandomization to direct stenting versus stenting after balloon predilatation. Overall, results with the S670 stent showed excellent success and safety, with delivery success of 99%, a 14-day adverse event rate of 6.8% (including 6.5% non–Q-wave myocardial infarction), and favorable angiographic (20%) and clinical (12%) restenosis rates. Direct stenting was successful in 92% of cases, with a 99.5% secondary success rate including additional pretreatment of initially unsuccessful direct-stenting attempts, and no increase in complications. There were modest (10%) savings in fluoroscopy time, contrast use, and a decrease in angioplasty balloon use (0.6 vs 1.3 balloons/case), but no reduction in clinical or angiographic restenosis. Patients treated later in the study, with a device that had less balloon extension beyond the edges of the stent, had slightly lower angiographic restenosis rates (19% vs 23%). In conclusion, the S670 stent showed excellent overall performance. Although direct stenting was safe and highly successful, it offered only modest cost savings, and no reduction in late restenosis compared with stenting after predilatation.     

Effects of increasing balloon pressure on mechanism and results of balloon angioplasty for treatment of restenosis after Palmaz-Schatz stent implantation: An angiographic and intravascular ultrasound study

Repeat balloon angioplasty is a widely used therapeutic option for in-stent restenosis, but the optimal balloon inflation pressure has not yet been determined. We used angiography and intravascular ultrasound imaging to assess the mechanism and results of lumen enlargement at various inflation pressures. Thirteen consecutive patients with restenosis post–Palmaz-Schatz stent implantation were submitted to a four-step balloon angioplasty using increasing balloon pressure of 2, 4, 8, and >12 atm. As a global result, the lumen size was only 80% of that observed at stent implantation. Significant changes in angiographic minimal lumen diameter, minimal lumen cross-sectional area, and lumen volume were observed after each step except after the highest-pressure inflation. At low inflation pressure (<8 atm), the decrease in neointimal tissue and the stent over expansion explained the lumen enlargement, whereas after further high inflation pressure (>8 atm), only additional stent over expansion was observed. These results suggest that only moderate balloon inflation pressure (up to 12 atm) is needed for angioplasty of post–Palmaz-Schatz stent restenotic lesions. Cathet. Cardiovasc. Intervent. 46:314–321, 1999. © 1999 Wiley-Liss, Inc.     

Randomized comparison of coronary stenting with optimal balloon angioplasty for treatment of lesions in small coronary arteries.

AIMS: Angioplasty of lesions in small coronary arteries remains a significant problem because of the increased risk of restenosis. The aim of this study was to compare the efficacy of elective coronary stent placement and optimal balloon angioplasty in small vessel disease. METHODS: One hundred and twenty patients with lesions in small coronary arteries (de novo, non-ostial lesion and reference diameter <3 mm) were randomly assigned to either balloon angioplasty or elective stent placement (7-cell NIR stent). The primary end-point was restenosis at 6 months follow-up. Optimal balloon angioplasty was defined as diameter stenosis less than or = 30% and the absence of major dissection after the angioplasty, and crossover to stenting was allowed. RESULTS: Baseline clinical and angiographic characteristics were similar in the two groups. Procedure was successful in all patients, and in-hospital events did not occur in any patient. However, 12 patients in the angioplasty group were stented because of suboptimal results or major dissection. Postprocedural lumen diameter was significantly larger in the stent group than in the angioplasty group (2.44 +/- 0.36 mm vs 2.14 +/- 0.36, P<0.05, respectively), but late loss was greater in the stent group (1.12 +/- 0.67 mm vs 0.63 +/- 0.48, P<0.01, respectively). The angiographic restenosis rate was 30.9% in the angioplasty group, and 35.7% in the stent group (P = ns). Clinical follow-up was available in all patients (15.9 +/- 5.7 months) and clinical events during the follow-up were similar in both groups. CONCLUSIONS: These results suggest that optimal balloon angioplasty with provisional stenting may be a reasonable approach for treatment of lesions in small coronary arteries.     

Six-month intravascular ultrasound follow-up of coronary bifurcation lesions treated with rapamycin-eluting stents: technical considerations

INTRODUCTION AND OBJECTIVES: In vitro studies show that stents deform when dilated laterally to access a side branch. This phenomenon may be avoided by use of a kissing balloon at the end of the procedure. However, to date, no in vivo data are available. Our objectives were to investigate the main vessel stent using intravascular ultrasound (IVUS) at six-month follow-up in 55 patients with bifurcation lesions treated using rapamycin-eluting stents and to examine the effect of technical factors. PATIENTS AND METHOD: All patients were treated using provisional or T stents. At 6 months, IVUS measurements were made in the main vessel at both proximal and distal ends of the stent, in reference segments, immediately below the side branch ostium, and at the points where the lumen was smallest and where stent expansion was greatest. RESULTS: The lumen area immediately below the side branch ostium was significantly smaller than that at the point of maximum stent expansion (6.7 [1.8] vs 5.1 [1.3] mm2; P<.05). Underexpansion was not influenced by use of a kissing balloon (stent area immediately under the side branch ostium: 5.5 [0.9] vs 5.6 [1.6] mm2; P=NS) and only one patient experienced restenosis at this point. The lumen areas at the proximal and distal edges of the stent were almost identical in patients who did or did not undergo balloon dilation beyond the ends of the stent. CONCLUSIONS: Stent underexpansion below the side branch ostium was frequently found following provisional or T stenting of bifurcation lesions. This minor stent deformity was not prevented by use of a kissing balloon nor by any specific side branch treatment and had no significant impact on the restenosis rate.     

Direct coronary stenting versus stenting with balloon pre-dilation: incidence of enzyme release and follow-up results of a multicentre, prospective, randomized study. The CK and Troponin I Estimation in direct STenting (CK TEST) trial

AIM: The aim of this study was to assess the safety of direct coronary stenting, its influence on costs, duration of the procedure, radiation exposure, clinical outcome and the incidence of periprocedural myocardial damage as assessed by enzyme release determination. METHODS: We randomized 103 patients (109 lesions) to direct stent implant or stent implant following balloon predilatation. Patients with heavily calcified lesions, bifurcations, total occlusions, left main lesions and very tortuous vessels were excluded. Three samples of blood were drawn; before, 12 and 24 h after the procedure and total CK, CK MB mass and troponin I determination was carried out in a single centralized laboratory. RESULTS: Direct stenting was successful in 62/62 lesions (100%). No single loss or embolization of the stent occurred. All stents in the group with predilatation were effectively deployed. The immediate post procedure angiographic results were similar with both techniques. Contrast media consumption and procedural time were significantly lower in direct stenting (150+/-82 cc and 30+/-13 min) than in pre-dilated stenting (184+/-85 cc and 36+/-14 min) (P=0.04 and P=0.036 respectively) while fluoroscopy time was similar (9.1+/-12 vs 9.19+/-15 min, P=0.97). The incidence of enzyme release was similar in the groups with only three non Q MI all in the pre-dilated group (P=0.149). Any elevation of CK MB and troponin I occurred in 7% of direct stent vs 12% of pre-dilated group (P=0.66), isolated troponin I elevation in 21% of both groups. Major adverse cardiac events during hospitalization were 0 in direct and 3 in pre-dilated stenting (P=0.66), but there were no significant differences at follow-up at 1, 6 and 12 months between the 2 groups (target lesion revascularization at 12 months 11 vs 14% in the 2 groups respectively). CONCLUSION: Direct stenting is as safe as pre-dilated stenting in selected coronary lesions. Acute results and myocardial damage as assessed by enzyme release determination are similar, but procedural costs (as measured by resource consumption) and duration of the procedure are lower in direct stenting. Overall success rate and mid-term clinical outcome are similar with both techniques.