Short- and Long-Term Outcome of Balloon Angioplastyfor Compromised Side Branches After Intracoronary

Stent Deployment

Neeraj Prasad, MD, Humara Ali, MD, and Leonard Schwartz, *MD

During coronary stent deployment there is a risk of compromising side branches, whichcan result in chest pain. Compromised side branches can be reopened by balloonangioplasty through the side of the stent. In a consecutive series of 10 patients withside-branch compromise and chest pain, balloon angioplasty through the side of the stentresolved the ischemia in all cases. The stented segment showed no deteriorationfollowing side-branch angioplasty. Six-month follow-up angiography showed a resteno-sis in the branch vessel of eight patients. The stented parent vessel restenosed in fourpatients. Therefore, side-branch balloon angioplasty after coronary stenting for ongoingischemia is technically feasible and immediately effective. Restenosis of the branchoccurs in most cases. Cathet. Cardiovasc. Intervent. 46:421–424, 1999.r 1999 Wiley-Liss, Inc.

Key words: side-branch compromise; coronary stent

INTRODUCTION

Side branches are present in over 50% of coronarysegments undergoing angioplasty and the majority ofbranches are medium sized [1]. During coronary stentdeployment there is a risk of compromising such brancheswithin the vicinity of the target lesion. Various definitionsof branch compromise have been stated, i.e., occlusion ofbranch [2,3], progression in branch disease [4], TIMIflow deterioration [5], or a minimum change of 20% [6],but none includes the symptoms that may result withinthe definition. Chest pain can occur in 15% of medium-sized side-branch compromise patients [2–14]. Compro-mised side branches can be reopened by balloon angio-plasty through the side of the stent. This study describesthe immediate and long-term results of this approach in acase series of 10 patients who were acutely ischemicfollowing the initial stent deployment and side-branchcompromise.

MATERIALS AND METHODS

This study was carried out at The Toronto Hospital(General Division), Toronto, Canada. All the angioplastyprocedures and follow-up angiograms were performed byone staff operator. Each patient gave written informedconsent for the initial procedure and the repeat follow-upangiogram.

The study population consisted of 10 consecutivepatients in whom side-branch occlusion or aggravationoccurred immediately after stent deployment and was

associated with ischemia. Prior to the angioplasty sixpatients had CCS class 4 angina, two had class 3, and twohad class 2 symptoms. In eight of the cases the branchangioplasty was performed using anACE balloon (Scimed,MN), which is a fixed wire catheter with a 1- or 2-cmsteerable wire tip. In the other two cases, a monorailballoon system was used. The balloon was passed throughthe side of the stent into the branch ostia and inflated toreopen the compromised branch. The original angioplastywire used for stent deployment of the main artery was leftin place during the side-branch angioplasty for potentialaccess but on no occasion did the side-branch treatmentaggravate the main vessel, so no subsequent redilatationof the stent was performed. Repeat coronary angiographywas carried out 6 months after the procedure to assess theangiographic results. The angiographic results were mea-sured by quantitative coronary angiographic (QCA) analy-sis (Cardiac Measurement System, Medical ImagingSystems, Nuenen, the Netherlands) for the vessel size ofthe parent vessel and the side branch as well as thepercentage stenosis in the parent vessel. QCA analysiswas difficult to perform at the ostia in the branch vesseldue to the takeoff angulation of the branch. This segment

Division Of Cardiology, The Toronto Hospital, Toronto, Canada

*Correspondence to: Dr. Leonard Schwartz, 200 Elizabeth St, 13en-204, Toronto M5G 2C4, Canada.

Received 19 June 1998; Revision accepted 15 October 1998

Catheterization and Cardiovascular Interventions 46:421–424 (1999)

r 1999 Wiley-Liss, Inc.

TABLE I. Results of Parent Vessel and Side Branch a

Patient Parent vessel Side branch vessel

Baseline % stenosis(vessel size, mm)

Poststent% stenosis

Post-PTCA of sidebranch vessel % stenosis

6-month follow-up% stenosis

Parentvessel

Side branchvessel

Parentvessel

Side branchvessel

Parentvessel

Side branchvessel

Parentvessel

Side branchvessel

EB 70F Left anterior descendingcoronary artery

Second diagonal coronaryartery

74% (3.37) 80% (2.07) 8% 100% 14% 60% 52% 90%

MC 71F Right coronary artery Posterior descending artery 70% (3.57) 70% (2.13) 11% 70% 11% 0% 40% 70%RH 50F Left anterior descending

coronary arterySecond diagonal coronary

artery68% (2.90) 60% (2.26) 5% 80% 13% 20% 26% 80%

DW 80M Left anterior descendingcoronary artery

First diagonal coronary artery 74% (2.67) 80% (1.70) 21% 90% 19% 30% 31% 70%

PS 78F Left anterior descendingcoronary artery

First diagonal coronary artery 68% (3.36) 60% (2.43) 36% 60% 40% 40% 52% 70%

MD 80M Left anterior descendingcoronary artery

Second diagonal coronaryartery

76% (3.46) 30% (2.07) 0% 75% 0% 20% 39% 30%

MW 72F Left anterior descendingcoronary artery

First diagonal coronary artery 65% (3.47) 20% (2.33) 13% 90% 11% 10% 51% 90%

RC 42M Left anterior descendingcoronary artery

First diagonal coronary artery 80% (3.45) 70% (2.26) 11% 70% 18% 0% 34% 90%

IO 68F Left anterior descendingcoronary artery

Second diagonal coronaryartery

63% (3.54) 0% (1.66) 15% 80% 25% 30% 70% 30%

DL 64M Obtuse marginal artery Circumflex coronary artery 64% (4.05) 70% (2.64) 22% 90% 16% 30% 14% 80%Mean 70.0 [5.6] 41.4 [15.9] 20 [14.3]% 80.5 [12.1]% 16.6 [10.3]% 21.5 [8.1]% 40.8 [15.9]% 70 [22.6]%[SD] (3.34 [0.37]) (2.15 [0.3])aLuminal narrowing of the parent vessel and the side-branch ostium at baseline, postcoronary stenting, after side-branch balloon angioplasty, and at 6-month angiographic follow-up.

was therefore assessed independently by two experiencedangiographers. Restenosis was categorized as luminalnarrowing of greater than 50%. Cardiac enzyme (creati-nine kinase) measurements were evaluated at baselineand 16 hr postprocedure.

RESULTS

In these 10 patients (6 female, 4 male), the parentvessel lesion was successfully stented (Johnson & JohnsonPalmatz-Schatz stents in 5 patients, Cook Gianturco-Rubin stents in 4 patients, and ACS Multilink stent in 1patient). The mean deployment pressure was 15.5 atm(range, 12–18 atm). Chest pain occurred in each patientafter stent deployment, which was ischemic in nature. Allpatients subsequently had successful side-branch balloonangioplasty. The mean balloon pressure of the side branchwas 8.1 atm (range, 6–10 atm), the diameter of theballoons used were 2 mm in four patients and 2.5 mm inthe remainder. The results of the procedure for both theparent vessel and the side branch are shown in Table I.The stented segment showed no deterioration followingside-branch angioplasty (parent vessel minimum luminaldiameter after stent deployment 2.91 mm, parent vesselminimum luminal diameter after side-branch angioplasty2.84 mm, P 5 NS). In eight patients there were noobserved cardiac enzyme elevation (for these patients,CK at baseline5 77.4 IU/L; range, 1–214; CK postproce-dure 5 88.8 IU/L; range, 34–192). One patient had amoderate CK rise from 190 to 521 IU/L. This patient hadhad successful opening of the LAD and first diagonalbranch. However, the second diagonal branch occludedduring the procedure but this branch was not reopened;thus, this may have contributed to the cardiac enzymeelevation. The other patient had a rise in CK from 120 to281 IU/L postprocedure.

All 10 patients had repeat coronary angiography andthese results are shown in Table I. Parent vessel restenosisoccurred in 4 out of 10 patients and side-branch restenosisoccurred in 8 out of 10 patients. Two patients had earlyrepeat angiography at 3 months for severe angina andboth were referred for coronary bypass surgery. Theothers were all symptomatically improved at 6-monthfollow-up with six class 1, one class 2, and one class 3;none of these patients required repeat intervention.

DISCUSSION

This case series shows that if side-branch compromiseoccurs immediately following stent deployment and isassociated with chest pain, it is possible to reopen thebranch by balloon angioplasty without compromising thestent result and with effective resolution of the ischemicsyndrome. Furthermore, this approach is associated with

a low incidence of cardiac enzyme elevation. However,the long-term angiographic results are poor, with almostinvariable branch restenosis. This may not be surprisingas ostial and small vessel balloon angioplasty are bothassociated with higher restenosis rate (ostial restenosis68%, small vessel restenosis 40% to 55%) [15–18].Recently, there has been some concern about ballooningthrough the side of a stent as this has been associated withdistal stent distortion [19]. We did not notice this; byQCA there was no change in parent vessel diameter afterside-branch angioplasty. Four of the 10 patients didrestenose the stent site in the parent vessel and this mayreflect an early structural change induced by the side-branch angioplasty, but in three of these four patients thestents were only minimally restenosed. A larger studywould be necessary to evaluate this issue.

In summary, side-branch balloon angioplasty aftercoronary stenting for ongoing ischemia is technicallyfeasible and immediately effective; it is also associatedwith a low incidence of cardiac enzyme elevation. From along-term standpoint, restenosis of the side-branch os-tium is almost invariable, suggesting that alternativeapproaches such as kissing balloon or ostial branchstenting before stenting the main artery should be ex-plored for this clinical situation.

ACKNOWLEDGMENTS

We thank Sanh Bui for his help with the QCA analysis.

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