Coronary stenting without predilatation (SWOP): applicable technique in everyday practice

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.

Early results of direct coronary stenting in consecutive patients when multivessel, complex, long lesions, and small vessels are included

BACKGROUND

Direct coronary stenting is the dominant technique for coronary stent implantation, but previous randomized studies have strongly selected lesions to treat. To evaluate whether the results can be generalized to routine clinical practice, all consecutive patients with direct stenting in 15 hospitals were entered into a prospective registry. Single vessels and simple lesions, but also multivessel, complex and long lesions, and small vessels size (< or =2.5 mm) were included. Immediately results as well as clinical events within 30 days after the procedure were evaluated.

METHODS

Between April and November 2002, direct coronary stenting was performed in 452 consecutive patients (559 lesions) at 15 sites. Stents edge-protected by "sleeves" (SOX technology, NIR Stent, Boston Scientific) or with short transitional edge protection (STEP technology, Multilink Stents, Guidant) were selected to minimize vessel injury outside the stent edges during balloon inflation/deployment.

RESULTS

Stents were successfully implanted in 96% of lesions. Lesions were multivessel in 27%, type B2-C in 40%, very angulated in 28%, calcified in 18%, and longer than 20 mm in 10% of patients. Vessels were smaller than < or =2.5 mm in 27% of patients. Direct coronary stenting was unsuccessful in 25 lesions (24 patients) characterized by more unstable angina (p=0.07), more treated lesions (p<0.01), and more distal locations (p=0.001). Dissection occurred in 6% of patients, and one stent embolised. The 30-day follow-up period included 1 death (due to subacute occlusion), 11 (2.4%) acute myocardial infarctions (8 non-Q wave), and one stroke (following carotid surgery).

CONCLUSIONS

Direct coronary stenting yielded excellent results at 30 days although some expanded indications will be included.

Direct coronary stenting compared with stenting after predilatation is feasible, safe, and more cost-effective in selected patients: evidence to date indicating similar late outcomes

OBJECTIVES

To review the currently available data from studies assessing feasibility, safety, clinical outcome and cost-effectiveness of direct stenting.

BACKGROUND

With technical advances of stent designs and their delivery systems a new strategy has become increasingly popular: direct stent implantation without prior balloon dilatation.

METHODS

The Medline database was searched from January 1996 to March 2001 for clinical trials investigating direct stenting using the index terms direct stenting, coronary intervention, percutaneous transluminal coronary angioplasty (PTCA), PCI, angioplasty and ischemic heart disease. Studies were chosen based on the number of patients involved and endpoints mentioned. Data not yet published but presented at recent international meetings were also included. A comparison between direct stenting and stenting with predilatation was performed using for the latter results of the randomized trials supplemented with Benestent II data.

RESULTS

At least 26 studies have investigated direct stenting, showing high primary and final success rates with few complications. Direct stenting provides a way to reduce costs, shorten procedural and fluoroscopy times and lower material consumption. Immediate and long-term clinical outcomes appear to be similar to stenting with predilatation. Preliminary results of large randomized trials with angiographic follow-up indicate that restenosis rates are similar to those of conventional stenting strategies.

CONCLUSIONS

Direct stenting compared with stenting with predilatation is feasible, safe, faster and more cost-effective. The evidence to date shows similar late outcomes.

Mechanism of lumen enlargement with direct stenting versus predilatation stenting: influence of remodelling and plaque characteristics assessed by volumetric intracoronary ultrasound

OBJECTIVE

To compare the effects of arterial remodelling and plaque characteristics on the mechanisms of direct stenting and predilatation stenting. Direct stenting has become routine in some laboratories and differs technically from predilatation stenting.

METHODS

Pre- and post-interventional volumetric intravascular ultrasound (IVUS) was undertaken in 30 patients with direct stenting and in 30 with predilatation stenting of non-calcified native coronary lesions, using the same stent design and stent length. Lumen, vessel (external elastic membrane (EEM)), and plaque (plaque + media) volumes were calculated. Remodelling was determined by comparing the EEM area at the centre of the lesion with the EEM areas at proximal and distal reference sites. Plaque eccentricity was defined as the thinnest plaque diameter to the thickest plaque diameter ratio. Plaque composition was characterised as soft, mixed, or dense.

RESULTS

All volumetric IVUS changes were similar in the two groups. Pre-intervention remodelling remained uninfluenced after direct stenting, but was neutralised after predilatation stenting. Eccentric lesions responded to intervention by a greater luminal gain owing to greater vessel expansion in direct stenting. Plaque composition influenced luminal gain in direct stenting, the gain being greatest in the softest plaques; in predilatation stenting, luminal gain was equivalent but vessel expansion was greater for "dense" plaque and plaque reduction greater for "soft" plaque.

CONCLUSIONS

In non-calcified lesions, the mechanisms of lumen enlargement after direct or predilatation stenting are significantly influenced by atherosclerotic remodelling, plaque eccentricity, and plaque composition.

Is direct stent implantation without predilatation safe? Acute and long-term outcome

Direct stenting could potentially lead to a reduction in dissections, time, and restenosis at 6-month follow-up. Using the premounted Palmaz-Schatz Crown stent elective stenting was performed without predilatation in 61 consecutive patients who were compared with a control group of provisional stenting. All patients underwent clinical and angiographic follow-up at 6 months. Direct stenting was successful in 81% of patients. In 16% of the patients predilatation was needed. In 3% the stent could not be implanted despite predilatation. Stent dislodgment occurred in 2% of patients, without embolization. Six-month angiographic follow-up was performed in 51 (84%) of 61 patients. In the direct stenting group the mean preprocedural minimal luminal diameter (MLD) increased from 0.96 +/- 0.47 to 3.09 +/- 0.54 mm directly after the procedure. At 6-month follow-up the MLD measured 2.32 +/- 0.79 mm. In the provisional stenting group the mean MLD increased from 0.92 +/- 0.51 to 2.44 +/- 0.58 mm and was 1.84 +/- 0.70 mm at 6-month follow-up. Restenosis, defined as a diameter stenosis > 50%, occurred in 8% of the direct stenting group compared with 28% in the provisional stenting group (P < 0.001). Direct coronary stent implantation can be attempted safely and efficaciously. The risk of stent loss is low. The initial and long-term angiographic results are significantly better as compared with provisional stenting. The risk of restenosis is significantly lower.

[Direct Stenting without Predilation: a Single-Center Experience with 1,000 Lesions]

INTRODUCTION

Direct stenting has been shown to save costs, procedural time, radiation, and contrast use. We analyze the results of direct stenting in daily practice.

MATERIAL AND METHODS

We retrospectively analyzed the interventions in the first 1,000 lesions that were treated with direct stenting at our center. Primary success, dissection, need for additional dilation, embolism, stent loss, and side branch occlusion were the variables assessed.

RESULTS

Direct stenting was attempted in 1,000 lesions in 784 patients (age 63 11 years, females 21%, diabetes 37%). Primary or rescue angioplasty was performed in 8%. One or more thrombi were found in 16%, bifurcation in 9%, calcification in 5%, angulation in 2.3%, and tortuosity in 3.2%. The reference diameter was 3.0 0.5 mm. The primary success rate was 93.1%. Failure of direct stenting (6.9%) was associated with the circumflex artery in 38%, calcification in 26%, angulation in 22%, and tortuosity in 31%. In 39 lesions, additional dilation with different balloons was required. Additional stenting was required for dissection in 40 lesions and secondary to incomplete coverage of the lesion in 27. Thrombus embolism occurred in 7 lesions, 6 of them with a previously visible thrombus and one in a vein graft. Stent embolisms occurred in 6 cases, 4 of which were retrieved. Four side branches became occluded, but 2 of them were recovered at the end of the procedure.

CONCLUSIONS

Direct stenting is a safe technique with low percentage of dissection, need for postdilation, thrombus embolism, and side br

Comparison of direct coronary stenting with and without balloon predilatation in patients with stable angina pectoris. BET (Benefit Evaluation of Direct Coronary Stenting) Study Group

The purpose of this study was to compare the effects of stent placement with and without balloon predilatation on duration of the procedure, reduction of procedure-related costs, and clinical outcomes. Although preliminary trials of direct coronary stenting have demonstrated promising results, the lack of randomized studies with long-term follow-up has limited the critical evaluation of the role of direct stenting in the treatment of obstructive coronary artery disease. Between January and September 1999, 338 patients were randomly assigned to either direct stent implantation (DS+; 173 patients) or standard stent implantation with balloon predilatation (DS-; 165 patients). Baseline clinical and angiographic characteristics were similar in the 2 groups. Procedural success was achieved in 98.3% of patients assigned to DS+ and 97.5% of patients assigned to DS- (p = NS), with a crossover rate of 13.9%. Compared with DS-, DS+ conferred a dramatic reduction in procedure-related cost ($956.4 +/- $352.2 vs $1,164.6 +/- $383.9, p <0.0001) and duration of the procedure (424.2 +/- 412.1 vs 634.5 +/- 390.1 seconds, p < 0.0001). At 6-month follow-up, the incidence of major adverse cardiac events including death, angina pectoris, myocardial infarction, congestive heart failure, repeat angioplasty, or coronary artery bypass graft surgery was 5.3% in DS+ and 11.4% in DS- (p = NS). Multivariate analysis demonstrated that major adverse cardiac events rates were related to stent length of 10 mm (relative risk [RR] 3.25, 95% confidence intervals [CI] 1.36 to 7.78; p = 0.008), stent diameter of 3 mm (RR 2.69, 95% CI 1.03 to 7.06; p = 0.043), and complex lesion type C (RR 2.83, 95% CI 1.02 to 7.85; p = 0.045). Thus, in selected patients, this prospective randomized study shows the feasibility of DS+ with reduction in procedural cost and length, and without an increase in in-hospital clinical events and major adverse cardiac events at 6-month follow-up.