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Drug-Eluting Stent Implantation in Bifurcated Lesions with Balloon-Crushing Technique and 6 Fr Guiding Catheter: Immediate and M

Iñigo Lozano, MD, PhD, FESC, Pablo Avanzas, MD, PhD, FESC, Dae-Hyun Lee, MD, Garikoitz Lasa, MD, Juan Rondán, MD, César Moris, MD, PhD, FESC
Iñigo Lozano, MD, PhD, FESC, Pablo Avanzas, MD, PhD, FESC, Dae-Hyun Lee, MD, Garikoitz Lasa, MD, Juan Rondán, MD, César Moris, MD, PhD, FESC
Percutaneous coronary intervention (PCI) in bifurcations represents 15–18% of all lesions treated1 and has traditionally been associated with more complexity and restenosis. It has been demonstrated with bare-metal stents (BMS) that the strategy of provisional stenting provides better outcomes than the implantation of 2 stents.2 The progressive utilization of drug-eluting stents (DES) has increasingly led to treating bifurcations with 2 stents. Colombo described the crushing technique3 and later, Lim4 published in-hospital results with the balloon-crushing technique. The balloon-crushing technique involves a modification of the crushing technique in which 2 stents are implanted with the use of a 6 Fr guiding catheter, which may be especially important for radial access procedures. To date, there is only one paper describing in-hospital results employing the balloon-crushing technique in a small series of patients. The purpose of this study is to describe the in-hospital and mid-term results of 15 patients treated with balloon-crushing in a bifurcation lesion. Patients and Methods Design. This was a prospective study of a cohort of 15 patients who received 2 DES in a bifurcation lesion with the balloon-crushing technique. Lesions and patients. From April 1 to November 15, 2005, all patients with a classification type-D bifurcation lesion who were scheduled for PCI with 2 DES and 6 Fr guiding catheters were included prospectively in this study. The stents utilized were the Taxus® Express (Boston Scientific Corp., Natick, Massachusetts) and the Cypher™ stent (Cordis Corp., Miami, Florida). Patients with left main bifurcated lesions were included only after discussing their individual cases with the surgeons, who determined them unsuitable for surgery. All patients received information regarding the procedure and provided informed consent to undergo PCI. Procedure. Use of radial or femoral access and glycoprotein (GP) IIb/IIIa inhibitors were left to the operator’s discretion. The first DES is introduced into the side branch with adequate length to cover the distal edge of the side branch lesion, with the proximal end of the stent inserted 2–3 mm into the main vessel. Next, a balloon is introduced into the main vessel, with the distal edge covering the lesion and the proximal edge covering the proximal edge of the side branch stent. The next step is to inflate the stent of the side branch with a balloon-to-artery ratio of 1:1 (Figures 1 and 2). The side branch stent balloon and the coronary wire are then captured in the guiding catheter, and then the main branch balloon is inflated with a balloon-to-artery ratio of 1:1 (Figure 3). The procedure is completed with the deployment of the second stent to cover the main branch lesion and the 2–3 mm of the other stent that protrudes into the main branch (Figure 4); this is followed by balloon dilatation using the kissing technique (Figures 5 and 6). Quantitative coronary analysis (QCA). QCA was performed off-line using the Medis® (Medical Imaging Systems, Inc., Leiden, The Netherlands) prevalidated automatic system for border detection. Definitions. Myocardial infarction (MI): CPK elevation ? 2 times the normal level. Angiographic success: residual stenosis 30% with TIMI 3 flow and no major complications such as death or Q-wave MI. Follow up. An electrocardiogram (ECG) before and after PCI was performed, as well as CPK-MB at 8 and 24 hours after the procedure. The later follow-up information was obtained for all patients via telephone contact. Statistical analysis. Continuous variables are expressed as mean and standard deviation, and the qualitative ones as absolute data and percentage. Statistical analysis was performed using SPSS® version 12.0 software (SPSS, Inc., Chicago, Illinois). Results During the study period, a total of 1,790 lesions were treated in our center, 337 (18.8%) of which were bifurcated at a side branch greater than or equal to 2 mm. A total of 19 (5.6%) patients had a Duke classification type-D bifurcation lesion to be treated with 2 stents implanted at the start of the procedure. In 4 patients, the conventional crushing technique was used, and in 15 (4.4%) patients, balloon-crushing was employed. These last 15 patients represent the cohort of the present study. The decision to perform conventional crushing or balloon-crushing was at the discretion of the operator performing the procedure, because 3 of them performed BC in type-D bifurcations, and the remaining interventionalist used conventional crushing. The mean age was 71.6 ± 9.4 years, and 40% of the patients were diabetics. The radial approach was used in 4 cases (26.6%), and all of the procedures were elective (Table 1). In 9 cases (60%) the target lesion was the left main coronary artery. In all of these patients the right coronary artery was diseased, and intra-aortic counterpulsation was used in 6 of them. The reference diameter of the main vessel was 3.26 ± 0.31 mm and 2.90 ± 0.36 mm in the side branch. Kissing balloon inflation at the end of the procedure was completed in 13 cases (87%). As for the remaining 2 patients, the kissing balloon technique was not performed due to the inability to cross the lesion with the wire in 1 patient and with the balloon in the other (Table 2). Procedural success was achieved in all cases, however, 2 patients experienced non-Q-wave MIs. Both patients had acute coronary syndromes, one with TIMI 2 flow at the beginning of the procedure, and the other had visible thrombus in the target lesion. Despite the utilization of GP IIb/IIIa inhibitors and TIMI 3 flow at the end of the procedure, CPK elevation was unavoidable. Two patients died of sudden cardiac death, one on day-10 and the other on day-187. The patient who died on day-10 was diabetic, with an ejection fraction of 35% and a diffusely diseased target lesion in the left main coronary artery that was treated with 2 Taxus 2.5 x 16 mm stents. The patient who died on day-187 had an ejection fraction of 25% and a lesion in the left anterior descending (LAD) and diagonal branch, and was treated with a 3 x 18 mm Cypher stent in the LAD and 2.5 x 13 mm Cypher stent in the first diagonal. It was not possible to perform kissing balloon inflation at the end of the procedure. In this last case, stent thrombosis was documented 10 days before death. One patient needed new revascularization 3 months after the initial procedure at the ostium of the left main artery in a segment where one of the final kissing balloons was inflated, but not covered with the stent. A new Cypher stent was deployed without postprocedural events. The composite MACE at follow up was 5 (33.3 %): 2 deaths, 2 non-Q-wave MIs and 1 revascularization. Discussion The main finding of this study was that the treatment of bifurcated lesions may be attempted with 2 DES, 6 Fr guiding catheters and the balloon-crushing technique, with satisfactory in-hospital results. However, since the mid-term results are less satisfactory, more studies with larger numbers of patients are required before this technique can be recommended as appropriate treatment for such lesions. It has been demonstrated that the use of 2 bare-metal stents to treat bifurcated lesions is not superior to provisional stenting,2,5,6 and the results of the studies completed with DES may support this finding.7,8 However, there are some lesions, such as the Duke classification types D, E and F, where crossover to an additional stent may often be needed,7 requiring the “T”-stenting approach. T-stenting is associated with a relatively high restenosis rate due to the difficulty encountered in covering the ostium of the side branch, specially in cases with angles 9 the angiographic restenosis was 22.7%, but in 85% of the cases where the restenosis was at the origin of the side branch, the T-stenting technique had been used. It was due to this fact that, in our study, we did not employ the T-stenting technique on Duke type-D bifurcation lesions. There are techniques to treat bifurcated lesions that make it possible to cover the ostium of the side branch. In our center, we do not use the “culotte” technique due to the large amount of metal in the carina and main branch and the difficulty in accessing the side branch with the wire to perform the final kissing.10 The crushing technique described by Colombo3 allows for complete coverage of both branches. Based on that procedure, Lim developed a modification to perform the crushing with 2 stents and 6 Fr guiding catheters, as the 6 Fr size is ideal for the radial approach.4 At our center, we typically use the Long Brite Tip® 6 Fr guiding catheters (Cordis) which allow for deep intubation and work very well with the balloon-crushing technique. In our series, the in-hospital results were very satisfactory, as was the case in the previous report.4 However, the death of 2 of our patients leads us to be less optimistic about the mid- and long-term results. The outcome after discharge of the patients in the previous study was not noted.4 DES thrombosis has been associated with medication withdrawal, renal insufficiency, bifurcations, diabetes and low ejection fraction.11 In addition to this, the proper crushing technique and the absence of kissing inflation at the end of the procedure may also have played a role in the events.7,12,13 The balloon-crushing may be associated with the same limitations as the conventional crushing technique. Two studies reporting results of the crushing technique have been published to date. Moussa et al14 reported the clinical 6-month follow up results of 120 patients treated with 2 sirolimus-eluting stents. Procedural success was achieved in 97.5% of these patients; 1 patient died of noncardiac causes; 2 (1.7%) had subacute stent thrombosis and target lesion revascularization was required in 13 (11.3%) patients. One important detail from this series is that there were no cases of left main disease. Hoye et al15 treated 231 patients with 241 bifurcated lesions with paclitaxel- and sirolimus-eluting stents. After 9 months of follow up, 10 patients (4.3%) had events that were probably related to stent thrombosis. Of note, the rate for survival free of MACE was 83.5%, with independent predictors of MACE being left main artery intervention and multivessel disease. Of the 10 patients with suspected stent thrombosis, 5 were treated for a left main artery lesion. In that study, the target lesion was in the left main artery in 47 patients, thus those 5 patients represented 10.6 % of the total cohort. The high MACE rate in our study (33.3%) brings into question the safety of this technique. In our opinion, the use of a 6 Fr guiding catheter does not add any additional risk to the procedure compared with conventional crushing with larger catheters. We have identified two possible causes for the poor outcomes in these patients. First, the high-risk profiles of these patient may have played a role. In the case of the patient who died 10 days postprocedure, the cause of the death may have been related to fatal arrhythmias associated with the low ejection fraction,16 or to stent thrombosis, possibly facilitated by the presence of left ventricular dysfunction, diabetes, the bifurcation itself or the lesion’s location in the left main artery. In the second fatal event, with stent thrombosis at day-177 and death at day-187, the low ejection fraction, the bifurcation and the absence of kissing balloon technique at the end of the procedure may have contributed to the unsuccessful outcome. The 2 non-Q-wave MIs occurred in patients with previous TIMI 2 flow or visible thrombus, and the revascularization procedure was performed on a patient with distal left main disease and small vessels. The second reason for an unfavorable MACE rate could be attributable to the crushing technique itself, which has been associated with poor results, especially in patients with distal left main disease.15 Given the results of this study, we cannot recommend this technique until larger series with better outcomes are published. Study limitations. This study is severely limited by the small number of patients. Our initial aim was to study a larger population, but the unsuccessful follow-up results led us to alter our initial plan. Although the number of patients who experienced MACE was small, it represents a relatively high percentage in this series, and the seriousness of the events discourages the utilization of this technique until more data are available. In addition, as a consequence of the small number of patients, it has not been possible to identify the variables related to the events. The only inclusion criterion for this study was the presence of a Duke type-D bifurcation, independent of the lesion location, ejection fraction, access site and type of stents chosen. Thus, although all of the procedures were elective, the predominant treated lesion was located in the left main artery, a fact that explains the high percentage of intra-aortic counterpulsation usage. Consequently, a broad variability exists among these characteristics which precludes extrapolation of the results to a specific patient population. At the time of our study, we believed conventional crushing to be the most attractive approach for bifurcation lesions, and the purpose of this study was to test the novel balloon-crushing technique which was based on the conventional crushing method. For this reason, a control group was not included in the study’s design. Conclusions The balloon-crushing technique is a very clever approach for the treatment of true bifurcations with 2 DES and 6 Fr guiding catheters. However, though the initial results of our study are very attractive, the mid-term outcomes are less so, which leads us to recommend caution regarding the use of this technique until more data are available that might demonstrate its safety and efficacy.
References
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