TITLE: Long-Term Outcomes of Plaque Debulking with Rotational Atherectomy in Side-Branch Ostial Lesions to Treat Bifurcation Coronary Disease
ABSTRACT: Background. The prognosis after rotational atherectomy of a side-branch ostium to treat bifurcation coronary lesions is unknown.
Methods. This was a retrospective case-review study of 40 consecutive patients who underwent rotational atherectomy of the side-branch ostium to treat symptomatic bifurcation coronary lesions meeting the Medina classification (1,1,1) at our institution between 2003 and 2007.
Results. Twenty-two (55.0%) patients underwent rotational atherectomy of the side-branch ostium alone and 18 (45.0%) underwent rotational atherectomy of the both the main vessel and the side- branch ostium. Most of the patients (n = 37, 92.5%) had a drug-eluting stent placed in the main vessel after rotational atherectomy. Only 8 patients (20.0%) required side-branch stents, and 2 patients (5.0%) underwent a final kissing-balloon technique. No acute closure of the side branch or coronary perforation were observed. Major adverse cardiac events included cardiac death (n = 1; 2.5%), nonfatal myocardial infarction (n = 1; 2.5 %), target vessel revascularization (n = 2; 5.0%) and target lesion revascularization (n = 0; 0.0%) during the mean follow-up period of 21.3 ± 18.5 months.
Conclusions. The study demonstrated safety and feasibility of rotational atherectomy and provisional side-branch stenting to treat side-branch ostial lesions of true severe bifurcation coronary artery disease. The study results suggest that rotational atherectomy of a side-branch ostium prior to main-vessel stenting may be an option in selected patients undergoing complex bifurcation lesion angioplasty.
J INVASIVE CARDIOL 2009;21:598–601
Key words: bifurcation coronary lesion, drug-eluting stenting, complex PCI, side branch ostium
Percutaneous coronary intervention (PCI) of bifurcation coronary lesions is associated with lower procedural success rates and an increased rate of restenosis, stent stenosis and major adverse cardiac events (MACE).1,2 The introduction of drug-eluting stents (DES) was reported to improve the incidence of myocardial infarction (MI), target vessel revascularizations (TVR) and MACE after PCI of bifurcation coronary lesions compared to the use of bare-metal stents (BMS).3–5 However, the incidence of these clinical adverse outcomes still remains high.3–5 Mechanical debulking of bifurcation coronary lesions was proposed to prevent less plaque shifting, with increased preservation of side branches. Previous clinical studies have evaluated rotational and directional atherectomy of the main vessel in bifurcation coronary lesions, and have shown lower rates of TVR.6–8 In contrast, the impact of plaque debulking at the ostium of the side branch for PCI of bifurcation coronary lesions is unknown and remains to be investigated.
Methods
This is a retrospective case-series study of consecutive patients who underwent elective PCI with plaque debulking by rotational atherectomy involving the ostium of the side branch to treat symptomatic true bifurcation coronary lesions at our institution between May 2003 and December 2007. The baseline characteristics and follow-up clinical information were obtained from reviews of medical records. All coronary angiograms of the study patients were reviewed by board-certified interventional cardiologists. The true bifurcation coronary lesion was defined as a coronary lesion with ≥ 50% luminal diameter stenosis in the main vessel and in the ostium of the contiguous side branch, which was ≥ 2.0 mm in diameter, and specific plaque geography meeting the Medina classification (1,1,1), which has been defined elsewhere.
9 Briefly, in the Medina classification (1,1,1), bifurcation lesion plaque involves the main vessel and the side-branch ostium, and the plaque in the main vessel spreads across the ostium of the side branch. Myocardial infarction was defined according to the universal definition of MI published elsewhere.
10 The criteria included the detection of a rise and/or fall of troponin I, with at least one value > 0.1 ng/ml, together with myocardial ischemia with at least one of following: 1) symptoms of ischemia; 2) electrocardiographic (ECG) changes including new ST-T changes or new left bundle branch block; 3) development of pathological Q waves on ECG; 4) imaging evidence of new loss of viable myocardium or new regional wall-motion abnormality. Target lesion revascularization (TLR) was defined as repeat percutaneous or surgical revascularization of the target lesion. MACE was defined as a composite outcome of cardiac death, nonfatal MI or TVR.
Procedures. Prior to the procedures, all patients received oral aspirin 81 mg or 325 mg/day and clopidogrel 75 mg/day. Intravenous heparin 60–70 Units/kg was given with adjunctive use of a glycoprotein IIb/IIIa inhibitor (eptifibatide). The activated clotting time was maintained in the range of 250–300 seconds. Rotational atherectomy was performed in the side branch alone or sequentially in the main vessel and in the side branch using an alternating stepped-burr approach. In general, we began with a 1.25–1.75 mm diameter burr and increased in diameter by 0.25–0.5 mm increments to a final burr size corresponding to 60% of each reference vessel diameter. Following completion of rotational atherectomy, sequential or simultaneous (kissing) balloon inflations using a double-wire technique were performed in both vessels at the operator’s discretion.
11,12 In most of cases we tried a provisional strategy with stenting main vessels only. A second stent on the side branch was implanted if there was a significant stenosis in the side branch (> 70% luminal narrowing) after stenting a main vessel.
Statistical analysis. Continuous variables are expressed as mean ± standard deviation. Discrete variables are expressed as percentages. A Kaplan-Meier survival estimate was used to estimate MACE-free survival. Statistical analysis was performed using Stata statistical software, version 10.0 (StataCorp, LP, College Station, Texas).
Results
A total of 40 patients met our study criteria and had a mean follow-up period of 21.3 ± 18.5 months. The baseline demographics and risk factors are shown in Table 1. The study population included a patient who underwent rotational atherectomy of the distal left main artery and its bifurcation (Table 2). Three patients had in-stent restenoses resulting in bifurcation disease. The prior stent in each patient was implanted in the left anterior descending, left circumflex and right coronary arteries, respectively. Most of the patients (n = 37, 92.5%) underwent DES (sirolimus-eluting) deployment in the main vessel across the ostium of the side branch. Of these, 6 patients (16.2%) required provisional side-branch stents. Two patients had stents implanted in side branches without stenting of the main vessel. One patient did not have any stents placed because the target vessels were too small, with a luminal diameter n = 18) versus patients who underwent rotational atherectomy in a side-branch ostium alone (
n = 22). There was no difference in outcomes between the two groups.
Discussion
We report a retrospective case-review study to treat bifurcation coronary lesions using rotational atherectomy of side-branch ostial lesions to prevent tissue shift and closure of the side branch during stenting of the main vessel lesions. To the best of our know-ledge, this is the first report of long-term outcomes after plaque debulking involving side-branch ostia to treat the complex subgroup of bifurcation coronary lesions. Although we included patients with prevalent multivessel coronary artery disease who had complex coronary lesions, the incidence of adverse clinical outcomes remained low during long-term follow up.
Garot et al, in the PRESTO trial, reported the incidence of TVR and MACE (death, MI, TVR) at 17% and 18% at 9 months after PCI without plaque debulking for bifurcation coronary lesions, respectively.
13 In this trial, BMS were used in 80% of patients, and balloon angioplasty was performed in the remaining patients. Dauerman et al compared clinical outcomes between two groups with mechanical debulking (directional or rotational coronary atherectomy) versus balloon angioplasty for true bifurcation lesions.
7 At 1-year follow up, the incidence of TVR was much lower in the debulking group (28%) compared to the balloon-angioplasty group (53%;
p = 0.05).
The introduction of DES revolutionized clinical outcomes after PCI of complex coronary artery lesions including bifurcation lesions.
4,5 In SCANDSTENT trial, Kalbaek et al compared clinical outcomes between PCI with DES versus BMS to treat bifurcation coronary lesions.
4,5 They reported the incidence of MACE (death, MI and TLR) at 7.1% versus 29.4% (
p-value was not reported) at 7 months, respectively, and 19.3% versus 36.5% (
p = 0.054) at 36 months, respectively.4,5 As such, DES appear to reduce clinical adverse events compared with BMS. However, the risk of requiring TVR still remains considerably high, even in the era of DES.
Considering the previous study results, the combination of rotational atherectomy and DES placement primarily in the main vessel with provisional side-branch stenting appeared to be a promising approach to treat true complex bifurcation lesions.
4,5,7 In the PERFECT registry, Tsuchikane et al reported a very low rate of clinical adverse outcomes after pre-DES stent plaque debulking with intravascular ultrasound-guided directional coronary atherectomy in bifurcation coronary lesions (63% of the lesions were left-main bifurcations).
8 Coronary atherectomy was performed primarily in the main vessels (99/99 lesions, 100%), and only 3 lesions in side branches. In this registry, there were no deaths or MIs, and only a few patients (n = 2 /99, 2.0%) required TLR within 9 months post procedure. Our study result of a TLR rate of 0% appears to be consistent with the low incidence of TLR (2.0%) observed in the PERFECT registry.
Various stenting techniques to treat both branches at the bifurcation lesion (two-stent techniques) have been developed to optimize the treatment of this complex subgroup of lesions.
14–17 However, these two-stent techniques were reported to offer no advantage over stenting of the main vessel alone (single-stent technique), and increased the risk of complications.
18 Currently, stenting of the main vessel with provisional side-branch stenting seems to be the prevailing approach. In our study, either none or one stent was used in most of the patients (n = 34, 85.0%). Provisional side-branch stenting was required in only 6 patients (16.2%). No simultaneous two-stent techniques were employed. Coronary rotational atherectomy of the side-branch ostium prior to main-vessel stenting allowed for a single-stent strategy to treat complex bifurcation lesions.
The ostium of the side branch has been reported to be the most common location of restenosis after PCI of bifurcation coronary lesions. Colombo et al found 18 cases (25.8%) of focal restenosis among 66 patients with angiographic success and angiographic follow up after DES placement in coronary bifurcations.
3 Of these, there were 14 cases (77.8%) of restenosis at the ostium of the side branch and 4 cases (22.2%) in the main vessel. We believe that plaque debulking at the side-branch ostium prior to main-vessel stenting is a very rational approach to prevent acute closure and remote restenosis of the side branch. It may be considered especially when treating bifurcation lesions involving severe calcification or rich plaque burden. The present study is unique. It reports long-term clinical outcomes of angioplasty with debulking of side-branch ostial lesions prior to stenting of the main vessel to treat complex bifurcation lesions. The other unique finding in our study is that final kissing-balloon angioplasty was not performed in most of our patients. This finding suggests that routine kissing-balloon angioplasty may not be necessary in PCI with mechanical debulking of bifurcation lesions.
Study limitations. The limitation of our study derives from its retrospective case-series review and single institution experience with a small sample size. In addition, routine angiographic follow-up studies were not performed, therefore, only clinical events were available as study outcomes.
Conclusion
Our study demonstrates the safety and feasibility of rotational atherectomy of the side-branch ostium to treat true bifurcation coronary lesions. The results of this study suggest that rotational atherectomy of the side-branch ostium prior to main-vessel stenting may be an option in selected patients undergoing treatment for complex bifurcation lesions. A prospective, controlled study with larger sample size is warranted to address this question.
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