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Acute and Follow-Up Results Using a New Atherectomy Catheter for Proximal LAD Lesions and Influence on LCx Ostium
January 2007
Recently, it was reported that aggressive and optimal directional coronary atherectomy (DCA) using intravascular ultrasound (IVUS) can be performed with favorable outcomes.1–4 The benefit of DCA is thought to be the debulking of plaques in the main vessel without affecting the side branch. Proximal left anterior descending artery (LAD) stenosis and bifurcating lesions are therefore suitable lesions for this technique. The Flexi-Cut™ (Guidant Corporation, Indianapolis, Indiana) is a new atherectomy catheter that was used in our center from July 2001 to October 2004, with good results. This study examined the acute and chronic results (about 6 months after the procedure) of DCA for LAD proximal lesions using the Flexi-Cut and the effects of this device on the left circumflex (LCx) ostium.
Methods
Study populations and lesion characteristics. From June 2001 to October 2004, standalone DCA using the Flexi-Cut for LAD proximal lesions was performed in 74 patients (74 lesions). This study population consisted of consecutive patients with proximal LAD lesions, excluding lesions with a 180 degree arc of superficial calcium as assessed by IVUS, thrombus-containing lesions and restenotic lesions after stenting. These patients routinely underwent follow-up angiography approximately 6 months after the procedure. The variables recorded on patients were: age, gender, history of diabetes, hypertension (defined by current or previous therapy history or a history of blood pressure > 140/95 mmHg), degree of obesity (obesity was defined as a BMI > 27.5), smoking history and hyperlipidemia (per previous diagnosis). Diabetes was defined by the presence of fasting hyperglycemia treated with insulin, an oral hypoglycemic or diet. LAD ostial lesions were defined as existing within 5 mm from the LCx ostium, and bifurcation lesions were defined as having a side branch (angiographically > 2 mm). The criterion for target lesion revascularization during the follow-up period was the recurrence of symptoms with functional ischemia determined by exercise electrocardiography.
Procedure and medications. All patients had been taking aspirin for > 3 days before the procedure. During the procedure, heparin was given as a bolus 120 U/kg with an additional bolus to 2,000 U/hour. All patients received IVUS-guided DCA using a 7 Fr Flexi-Cut L size. Balloon pressures were increased progressively from 10 psi to a maximum 150 psi. Repeated debulking of the plaque using IVUS was performed according to residual percent plaque area (PA) plus the media cross-sectional area. The aim was to achieve a residual PA of Angiography and quantitative analysis. Angiography was performed before, after the procedure and at follow up using the same angiographic projection that revealed the highest degree of stenosis. Isosorbide nitrate (2.5 mg) was administered by intracoronary injection before each study. Offline quantitative coronary angiography (QCA) was conducted using the Cardiovascular Measurement System (Medis, Leiden, The Netherlands). Minimal lumen diameter, diameter stenosis, reference diameter and lesion length were calculated before, immediately after the procedure and at follow up by a blinded reader to the order of postintervention and follow-up cine angiograms. Analysis of cine frames was performed in end-diastole. Also, QCA to the ostium of the LCx was performed to determine the influence of LAD DCA on the origin of this vessel. Restenosis was defined as a diameter stenosis > 50%.
Results
Patients and characteristics. Patients and lesion characteristics are shown in Table 1. Ostial lesions were defined within 5 mm from the LAD ostium.
Acute and chronic QCA results. The results of pre-, post- and follow-up QCA results are shown in Table 2. Follow-up angiography was performed at 5.7 ± 0.5 months. Acute gain was 1.87 ± 0.78, late loss was 0.90 ± 0.90 and net gain was 0.96 ± 0.97. Binary restenosis and the target lesion revascularization rate were 12.2 and 9.5%, respectively.
IVUS results. IVUS results are shown in Table 3. Residual plaque area after DCA was 47.3 ± 8.7%.
QCA and follow-up results of the LCx ostium. QCA results of the LCx ostium are shown in Table 4. There was no severe stenosis at the LCx ostium before DCA in the LAD proximal lesions. Plaque shift into the ostium of the LCx was not seen.
Discussion
Sirolimus-eluting stents (SES) have recently been shown to significantly reduce restenosis rates after percutaneous coronary intervention.5–7 However, even when using SES, there were some problems regarding stenting at ostial or bifurcation lesions. Complex strategies such as crush stenting, Y-stenting, T- or modified T-stenting, and the kissing stent technique could lead to a high thrombosis rate8,9 and a high rate of restenosis on follow up.8–12 On the other hand, recent studies have shown that aggressive IVUS-guided DCA can be performed safely with favorable outcomes.1–4 The benefits of debulking bifurcation lesions with large side branches have been demonstrated.13 Patients did not need to be on adenosine diphosphate (ADP) receptor antagonists and had low thrombosis rates with aspirin alone. Furthermore, this study showed that good intermediate-term results, at approximately 6 months, could be obtained with DCA of the ostial LAD without compromising the LCx. Thus, we think that DCA for LAD proximal lesions is a feasible strategy that does not affect the LCx ostium.
The limitations of this study are its small size and potential selection bias. These procedures were performed only at our center. These results need to be verified by a large, multicenter study that would compare drug-eluting stents to a DCA strategy for ostial LAD treatment and on bifurcation LAD/LCx lesions.
References
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