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Cutting Balloon Coronary Angioplasty
in the Treatment of in-Stent Restenosis

Calvo Cebollero, Isabel; Galache Osuna,
José Gabriel; Sánchez Rubio Lezcano, Juan;
Alonso Francia, Carmen; Diarte de Miguel,
José Antonio; Salazar González, José Javier;
Moreno Esteban, Eva; Placer Peralta, Luis Javier.

Hospital Universitario Miguel Servet. Zaragoza. España

SUMMARY
Background: In-Stent restenosis is a yet non solved problem, and the best present therapy is to be determined.
Aim: Angiographic and clinical evaluation of effectivity and safety of Cutting Balloon (CB) treatment for this kind of lesions.
Material and Methods: 45 patients with 50 in-Stent restenosis lesions, CB treated from February 1999 and March 2001. Quantitative basal and post-CB dilatation angiographic evaluation was performed. Complication raised during the procedure and hospital stage were registered. The location of lesion was LAD in 48% of cases, CX in 22%, RCA in 20% and Saphenous Vein Graft in 10%. Mean severity of stenosis was 66,43± 18,78%with an 11,21 ± 10,20mm length. Minimum Luminal Diameter was 0,97 ± 0,05 mm. CB/ vessel diameter ratio 1,02. Average inflates/lesion was 1, 87 (rank 1-7) mode 2 . Average inflation pressure 7,94 atm.
Results: Procedure success was 94%. A new stent was implanted in 8 lesions (16%), and conventional ballooning was performed in 18 lesions (36%) to complete procedure. Medium Luminal Diameter post-CB 2,47 ± 0,09 mm, Medium Acute Gain was 1,50 ± 0,09 mm and Final Stenosis was 18,37% ± 18%. During procedure an acute occlusion occurred and was solved with a new stent. Two dissections, type A and type C were reported, another stent being implanted in the latest. No complications were reported until the hospital discharge.
Conclusions: CB Coronary Angioplasty is a highly effective and safe technique for the treatment of in-Stent restenosis. It is necessary to check the persistence of this good results at medium and long term.

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INTRODUCTION
   The use of coronary endoprostheses has substantially reduced the incidence of acute phase complications of dilatation and significantly decreased the occurrence of restenosis. However, the widespread use of coronary stents has turned in-stent restenosis into a major clinical problem the treatment of choice for which remains to be determined.

   The conventional balloon redilatation technique traditionally employed to treat this type of lesion results in unacceptable rates of restenosis (above 50%), particularly in the sub-group of patients with diffuse in-stent restenosis.

   Rotational and directional atheroablation procedures are technically complex and expensive. Also, they provide no advantage over plain balloon angioplasty (POBA). A randomized multicentre test (ARTIST) revealed the superiority of balloon angioplasty over rotational atherectomy followed by POBA in a 6-month clinical and angiographic monitoring test.

   The cutting balloon (CB) performs an incision and dilatation of the heart plate, so it combines the properties of the conventional balloon with those of radial atherectomy of the lesion by using 3-4 microblades 0.010 inches size that are located on the surface of a strainless?? balloon. Cutting balloon coronary angioplasty is an approach on the rise as a method for the treatment of in-stent restenosis that surpasses existing alternatives in simplicity, economy and, also probably, efficacy. The results of retrospective studies and small-scale randomized tests suggests that the CB technique may surpass conventional angioplasty or even the combination of rotational atherectomy and balloon angioplasty. The origin of the differ-ences is obscure; however, intracoronary ecographic findings suggest that the CB technique provides better final results than conventional balloon. As the CB is inflated, the neo-intimal tissue is forced out of the stent mesh, thereby improving the acute luminal gain and reducing the "watermelon seed" effect, all with little damage to the artery wall -and hence with little risk of complications following dilatation.

AIM
   To evaluate, in angiographic and clinical terms, the effectiveness and safety of the cutting balloon (CB) technique in the early treatment of in-stent restenosis.

PATIENTS AND METHODS
   An overall 45 patients with 50 in-stent restenosis lesions were treated with CB angio-plasty at the "Miguel Servet" University Hospital (Zaragoza, Spain) between February 1999 and March 2001. The procedure was always performed using the femoral way and the Judkins technique, the guiding catheter being of the 6F or 8F type, at the operator's discretion.

  Restenosis was used as the dichotomous variable (viz. a reduction to less than 50% of the vessel diameter within the stent and/or at its edges). The technical details of the procedure (CB diameter, inflation pressure, number of CBs used and associated procedures) were recorded and a basal and post-dilatation quantitative angiographic evaluation was performed by using the software bundled with the Monoplanar Cardiovascular System of the Integris H3000 Philips Medical System

   We examined the length of the lesion concerned, its severity, the basal and post-dilatation minimum luminal diameter (MLD) and the acute luminal gain (ALG). The procedure was deemed successful when the CB reached the lesion, crossed it and dilated it with less than 30% residual stenosis.

   Acute coronary events (death, myocardial infarction and the need for new percutaneous or surgical revascularization) were recorded, and so were clinical and vascular complications from performance of the procedure to discharge from hospital.

   The means for quantitative variables were compared via Student's t values.

RESULTS
   Of the 45 patients studied, 44 were males. The average age was 67 years (range 39-89). Fifty-five percent of the individuals were hypertensive, 57% dislipidemic, 31% diabetic and 40% smokers.

   An overall 50 lesions were treated. Forty-eight percent were located in the DA territory, 22% in CX, 20% in CD and 10% in saphenous vein grafts. Fifty percent of the lesions were located in a proximal segment.

   The reference vessel diameter was 3.1 ± 0.65 mm. The average severity of the stenosis, as the percent diameter reduction, was 66.43 ± 18.78% and the average length 11.21 ± 10.20 mm. The minimum luminal diameter was 0.97 ± 0.05 mm.

   The average CB/vessel diameter ratio was 1.02 (range 0.7-1.04). The average number of CB inflations per lesion was 1.87 (range 1-7, mode 2) and the average inflation pressure 7.94 atm (range 6-11).

   The procedure was successful in 100% of the 45 patients. That of CB angioplasty was 94% (47 of the 50 lesions dilated). In two cases where the CB failed to reach the lesion or cross it, conventional balloon proved successful. One case involved acute occlusion of the vessel following dilatation, which was solved by implanting a new stent.

   The average post-CB luminal diameter was 2.47 ± 0.09 mm, the average acute gain 1.50 ± 0.09 mm and the final stenosis 18.37 ± 18%.

   Eight lesions (16%) required implantation of a new stent owing to restenosis of the edge and 18 (36%) the additional use of conventional balloon.

   The events recorded during the procedure included one acute occlusion (the case deemed as CB failure) and 2 dissections (of the A and C types, which were both treated by implanting a new stent). There were no complications such as perforation, distal embolization or slow flow.

   There were no complications between completion of the procedure and discharge from hospital. No death or infarction arose, nor was any additional revascularization procedure required. Also, no vascular complications requiring surgical repair or transfusion were encountered.

DISCUSSION
   The CB technique is the treatment of choice for in-stent restenosis in our hospital. The results of this study show that the procedure provides a high initial rate of success that surpasses those obtained in other scenarios. Probably, those vessels amenable to stent implantation are also anatomically suitable for passage of a CB. Tortuous and calcified coronary vessels, which are difficult to penetrate by a CB, also result in failure of a stent to progress.

   The two cases in our series where the CB failed to reach the lesion were a severe focal restenosis in the middle segment of a right coronary artery with two elongated stents overlap-ping in the proximal and middle segments of the vessel, and a severe diffuse restenosis in the obtuse marginal branch with an angle of entry into the vessel exceeding 90°. In both cases, failure of the CB was a result of the anatomic characteristics of the lesion and vessel, and also of the poor profile and impaired maneuverability of the CB relative to the conven-tional angioplastic balloon.

   Atherectomy was done with an associated procedure in 52% of the lesions. Post-dilatation with a conventional balloon was indicated in order to level the vessel lumen and improve the minimum luminal diameter particularly when the restenotic lesion was of the diffuse type and had been dilated with multiple sequential inflations. A new stent was implanted in apposition to or overlapped with the pre-existing one when the restenosis affected the stent edges. In this situation, remodeling of the vessel is bound to derive little advantage from CB atherectomy, so implantation of a new stent is to be preferred.

   Worth special note is the absence of acute coronary events or complications during hospital stay. Whether the excellent results obtained in the acute period will hold during the follow-up remains to be seen.

CONCLUSIONS
   Cutting balloon coronary angioplasty is a highly effective and safe technique for the treatment of in-stent restenosis, at least initially. Whether the good initial results persist in the middle and long run will have to be checked in due course.

 

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2nd Virtual Congress of Cardiology

Dr. Florencio Garófalo
Steering Committee
President
Dr. Raúl Bretal
Scientific Committee
President
Dr. Armando Pacher
Technical Committee - CETIFAC
President
fgaro@fac.org.ar
fgaro@satlink.com
rbretal@fac.org.ar
rbretal@netverk.com.ar
apacher@fac.org.ar
apacher@satlink.com

Copyright© 1999-2001 Argentine Federation of Cardiology
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