Clinical and angiographic predictors of immediate recoil after successful coronary angioplasty and relation to late restenosis

Clinical and Angiographic Predictors of Immediate Recoil After Successful Coronary Angioplasty and Relation to Late Restenosis Yoseph Rozenman, MD, Dan Gilon, MD, Sima Welber, MSc, Dan Sapoznikov, PhD, and Mervyn S. Gotsman, MD The effect of immediate recoil on the results of balloon angioplasty was examined in a group of 416 patients (696 lesions) who underwent SW cessful coronary angioplasty. Immediate recoil was responsible for loss of 0.42 + 0.64 mm from the potentially achievable lesion diameter, and represented 23% of the actual gain in diameter. The immediate recoil was determined mainly by the degree of arterial stretch, which is best repro sented by the balloon to normal artery size ratio (correlation coefficient 0.49, p cO.0001). Classic risk factors for coronary artery disease did not affect immediate recoil, except for a trend toward lower values in patients with history of hyperche lesterolemia. There was a tendency for lower rce coil in patients with residual coronary thrombus and in those who underwent angioplasty within 1 week of acute myocardial infarction. Recoil was larger in the left anterior descending artery than in the circumflex or the right coronary artery. Patients with more immediate recoil developed more restenosis (>50% stenosis at follow-up). However the late loss of luminal diameter due to the restenotic process was smaller in those who had larger initial recoil. It is concluded that immediate recoil after balloon angioplasty is an elastic phenom enon that is related mainly to the degree of arterial stretch. The relative importance of immediate recoil in determining the late outcome of coronary angioplasty is at least as important as the late re stenotic process. (Am J Cardiol1993;72:1020-1025)

From the Cardiology Department, Hadassah University Hospital, Jerusalem, Israel. This study was supported by a grant from the National Council for Research and Development, Israel and GSF Munchen, Germany. Manuscript received February 8, 1993; revised manuscript received and accepted June 14, 1993. Address for reprints: Yoseph Rozenman, MD, Cardiology Department, Hadassah University Hospital, P.O. Box 12000, Ein Kerem, Jerusalem, Israel 91120.

1020

THE AMERICANJOURNALOF CARDIOLOGY VOLUME72

I

mmediaterecoil is responsiblefor a significant loss of the potentially achievableluminal diameter after successfulcoronary angioplasty.1,2 The effect of recoil is much more prominent when balloon dilatation is compared with other techniques, such as directional atherectomyor coronary stents.3The final coronary stenosis is determinedby the immediate residual stenosis after angioplasty and by the late loss of the initially gained luminal diameterdue to the restenoticprocess.4-9 Becauseballoon size is matched to the normal arterial diameter,tOthe immediate residual stenosisafter angioplasty is due mainly to elastic recoil. In this report the importance of immediate recoil is reexamined.We will examine the clinical and angiographicpredictors of this process and the relation of immediate recoil to late restenosis. METHODS Patients: This study describes the results from a group of 416 patients(596 lesions)who were successfully treated with balloon angioplasty. The study group consistsof patientswith stableand unstableangina,and of patients with postmyocardialinfarction ischemia (patients treated with angioplasty during the course of evolving myocardialinfarction are not included). In 280 of thesepatients (397 lesions), a secondangiogramwas recorded >l month after the initial angioplasty and the presenceof restenosis(>50% stenosison the follow-up angiogramof a lesion that was successfullydilated) was determined. Coronary angiography and angioplasty: Coronary angiography was undertaken using 4.5~inch General Electric image intensifier with an overframing lens to achieve maximal optical magnification of the arteries. Multiple oblique views were taken to detine the details of each coronary lesion. Intravenousnitroglycerin ink sion (titrated to decreasesystolic blood pressureby 15% or to a pressureof 110mm Hg) and a 10,000U bolus dose of heparinwere begun before the angioplasty.Standard equipmentwas used for the angioplastyprocedure. Maximal intlation pressurewas 6 to 8 atm in most patients. Minimal residual stenosiswas attemptedafter angioplasty by increasingballoon size whenevernecessary. Repeatangiograms22 views were recorded2 to 3 minutes after the last balloon inflation to assessthe iinal result. Data analysis: The coronary angiogramwas examined by an experiencedobserver.The site of each lesion was determinedusing a detailed 116-segment model that takes into account the origins and points of branching of the vessels.” The severity of the stenosiswas meaNOVEMBER1,1993

TABLE I Summary of Angiographic Analysis of the 596 Coronary Lesions

TABLE II Clinical Predictors of Acute Recoil After Balloon Angioplasty

Lesiondiameter (mm) Before angioplasty After angioplasty Follow-up* Normal artery diameter (mm) Balloon diameter (mm) Ratiot Lesion length (mm) Diameter changes Potential gain Absolute (mm) Relative (%I Actual gain Absolute (mm) Relative (%) immediate loss (recoil) Absolute (mm) Relative (%) Late loss* Absolute (mm) Relative (%) *Data are available for 397 lesions. TThe ratio between balloon and normal arterial diameters. defined in the methods section. Values are mean k SD.

Immediate Recoil 0.85 2.68 1.90 3.16 3.10 0.99 10.3

+- 0.58 ? 0.69 t 1.08 + 0.54 * 0.49 _t 0.13 + 5.8

2.25 f 0.67 72 r 21 1.83 + 0.82 58 + 25 0.42 k 0.64 14 2 21 0.75 -t 1.06 24 F 33 Gains and losses are

Age <55 >55, <63 >63 Gender Men Women Risk factors Hypertension Yes No

Diabetes mellitus Yes No

Smoking Yes No

Hypercholesterolemia Yes No

Family history Yes No

sured using a high-magnification projector and mechanical calipers using a single end-diastolic frame in the projection with the most severenarrowing. Lesion diameterswere measuredtwice (>6 months apart) in 54 lesions by the same observer to assessintraobserver variability. The specific frame, or projection, in which the initial measurementswere undertaken were not available to this observer during the second measurement. The standarddeviation of the differencebetween the 2 measurementswere 0.41 and 0.28 mm, and 8.6% for normal arterial diameter,lesion diameterand percent stenosis,respectively. The following values were noted for each lesion: (1) cathetersize for calibration; (2) normal vessel diameter as the mean of the normal diameters,proximal and distal to the lesion; (3) minimal diameter obtained at the view in which the lesion was most clearly visualized (using the same view for comparisonsbetween the lesion in successiveangiograms);(4) lesion length; and (5) angioplasty balloon diameter (we took the largest measurementwhen multiple balloons and inllations were performed).Absolute normal arterial diameter,lesion diameter,lesion length and percentstenosiswere then calculated. Each lesion was measured on the preangioplasty, postangioplastyand follow-up angiograms.Potential/(actual) immediate gain in lesion diameter was decked as the difference between balloon diameter/ (postangioplastylesion diameter) and preangioplastylesion diameter.Immediate recoil was detied as the difference between balloon diameter and postangioplasty lesion diameter,and late loss as the differencebetween postangioplastyand follow-up lesion diameters.Relative gains and losses were debed as the absolute correspondingvalues divided by preangioplastynormal arterial diameter. Statistical analysis: Values are presentedas mean 5 SD. The t test and correlation coefficientswere used

Lipid profile* LDL cholesterol (mgidl) < 124 >124, <157 > 157 HDL cholesterol (mgidl) <35 >35, <45 >45 Clinical presentation Stable AP Unstable AP After MI

Number of Patients

Absolute (mm)

Relative (%)

202 205 189

0.36 5 0.60 0.46 f 0.66 0.44 k 0.66

12 f 20 15 * 22 15 Lk 22

474 122

0.42 + 0.64 0.39 f 0.64

14 2 22 13 f 20

286 301

0.42 f 0.63 0.43 -+ 0.64

14 +- 22 14 * 21

134 453

0.43 f 0.63 0.43 f 0.63

14 2 22 14 t 21

118 470

0.36 + 0.61 0.44 + 0.64

11 + 19 15 i 22

277 308

0.38 t 0.61 0.47 t 0.65

13 f 21 15 2 21

286 301

0.43 2 0.65 0.43 k 0.61

14 2 22 14 r 20

99 117 87

0.43 2 0.60 0.36 zk 0.59 0.32 k 0.66

14 r 20 13 f 22 10 r 19

107 116 86

0.40 -+ 0.67 0.41 2 0.59 0.28 k 0.56

13 + 23 14 + 20 10 + 18

246 247 72

0.43 ? 0.64 0.46 r 0.60 0.31 f 0.72

14 -+ 21 16 2 21 10 L 23

*Similar results were obtained for the other lipid fractions (triglycerides, total cholesterol, and very low density lipoprotein cholesterol). AP = angina pectoris: HDL = high-density lipoprotein; LDL = low-densely Ihpoprotein; MI = myocardial infarction; VLDL = very low density lipoprotein.

to assessrelations between variables. In addition, to study the effect of continuousvariableson immediaterecoil, the whole group was subdividedinto 3 subgroups using 2 cutoff values of the variables to separatebetween subgroups.To avoid bias that could be introduced by selectionof specific cutoff values, thesewere chosen to create subgroupswith an equal number of observations. One-way analysis of variance and the Bonferoni correction were used to compare among these subgroups.A p value ~0.05 was consideredstatistically significant. RESULTS Table I summarizesthe angiographicdimensionsof the coronary lesions, normal arteries,balloon size and balloon to normal artery size ratio. The calculatedgains and losses in lesion diameter are also presented.Acute recoil was responsiblefor a loss of 0.42 + 0.64 mm (14 * 21% of normal arterial diameter)immediately on balloon deflation.Acute recoil is thus responsiblefor a loss of 19% of the potential gain in lesion diameter,and it represents23% of the actual gain. RECOIL AFTER ANGIOPLASTY 1021

TABLE III Correlation Coefficients Between Angiographic Variables and Acute Recoil After Balloon Angioplasty Immediate Recoil Absolute Lesion diameter (mm) Before angioplasty After angioplasty Follow-up* Normal artery diameter (mm) Balloon diameter (mm) Ratio* Lesion length (mm) Diameter changes Potential gain Absolute (mm) Relative (%) Actual gain Absolute (mm) Relative (%) Late loss Absolute (mm) Relative (%I *See legend toTable

p Value

Relative

p Value

-0.03 -0.73 -0.16 -0.07

-co.395 <0.0001 <0.0015 <0.108

-0.07 -0.78 -0.20 -0.20

10.097
0.27 0.43 -0.03

<0.0001 < 0.0001 <0.46

0.16 0.49 -0.05


0.17 0.32

< 0.0001 < 0.0001

0.23 0.28

<0.0001 <0.0001

-0.60 -0.61

<0.0001 <0.0001

-0.62 -0.60

<0.0001 <0.0001

-0.31 -0.29

<0.0001 10.0001

-0.29 -0.27

10.0001 <0.0001

I for explanations.

Clinical pmdii of acute recoil (Table II): Recoil was not influencedby age or sex. History of hypertension, diabetesmellitus, and family history of coronary artery diseasedid not affect the amount of recoil. History of hypercholesterolemiawas associatedwith less recoil (p = 0.0.55),however measuredcholesterol values did not correlatewith the amountof recoil. Stableor unstable angina did not influence recoil but there was a trend toward less recoil in patients with angioplastyin the week after acute myocardial infarction. Angiographic predii of ecute recoil (Tables Ill to V): Absolute recoil was similar in arteries of differ-

ent sizes; however, when normalized to normal arterial diameter,recoil was more significant in smaller arteries. Acute recoil increasedsignificantly with increasingballoon size. The most important predictor of absoluteand relative recoil was balloon to normal artery size ratio. This is a good measureof the degreeof stretch of the artery, and the greater the stretch the larger the recoil (Figure 1). Acute recoil was not influencedby the initial lesion diameter but was inversely related to the diameter of the lesion after the angioplasty.Recoil correlated with the potential gain in luminal diameter (determined in part by balloon size) and was inversely related to the actual gain (acute recoil = potential gain - actual gain). Initial lesion length did not affect immediate recoil, nor was it increased in eccentric or calcified lesions (0.40 f 0.62 mm and 0.36 If: 0.72 mm, respectively) compared with concentric noncalcified lesions (0.41 f 0.63 mm). There was a tendency for less recoil in lesions located in curves (0.30 IL 0.54 mm) and whenever a thrombus was angiographicallyidentified (0.25 f 0.57 mm). We found a sigticant difference in the amount of recoil among the major coronary arteries.

1022

THE AMERICAN JOURNAL OF CARDIOLOGY VOLUME 72

Both absoluteand relative recoil were larger in the left anterior descendingarteq than in the circumflex and right coronary arteries.Although balloon diameter was larger in the right coronary artery (matching the larger diameterof the artery) the balloon to normal artery size ratios were only minimally different among the arteries. Acute recoil and restenosis: Restenosis(deGnedas >50% diameter stenosisin the follow-up angiogramof a lesion that was successfullydilated) was presentin 138 of 397 lesions (35%) that were restudiedwith a second angiogram.Both absoluteand relative recoil were higher in the subgroupof patientsthat developedrestenosis: 0.52 f 0.75 mm and 18 f 26% in lesions with restenosis comparedwith 0.37 5 0.54 mm (p = 0.02) and 12 ? 17% (p = 0.007) in lesions that did not developrestenosis. When the amount of late loss of luminal diameter was correlatedwith the amount of immediate recoil, a highly significant negativecorrelationwas observed(Tables III and IV). Thus, even though the late loss in luminal diameterwas smaller in patientswith more recoil, the tial lesion diameterwas influencedmore by the immediateloss (recoil) than by the later restenoticprocess. DISCUSSION In this study,balloon to normal artery size ratio was 0.99, and the final diameter of the lesion after the dilatation was 0.48 mm less than the diameter of the normal artery.We believe that this diameter difference,evident immediately after balloon deflation,was not due to active vasoconstrictionor mural thrombus becauseall patients were pretreatedwith nitroglycerin12and heparin. We thus conclude, as was previously suggested,1,2 that elastic recoil is responsiblefor the immediate observedloss in luminal diameter after angioplasty. Immediaterecoil was independentof age,genderand risk factors (except for history of hypercholesterolemia that was associatedwith less recoil). Slightly less recoil occurredin patientstreatedwithin 1 week of myocardial infarction than in those with stable or unstable angina. Also, patients in whom a clot was suspectedangiographically manifestedless immediate recoil. After myocardial infarction patients may have residual thrombus in the artery.This is fragmentedby balloon dilatation so that the mechanism of luminal dilatation in these patients is different from that observedin other patients. This may account for the trend toward less recoil. Our observationssuggest that greater stretching of the artery during angioplastyis associatedwith more recoil. Acute recoil was thus sigticantly correlatedwith balloon to normal artery size ratio. Similar observations were made by Rensing et a11,2;they suggestedthat regional arterial differencesin elastic recoil are explained by regional differencesin the degreeof stretching.Elastic recoil was significantly greaterin the left anterior descendingthan in the right coronary artery.Differencesin the responseof the arteries to balloon angioplastyand to other techniques for arterial dilatations (coronary atherectomyand stent), and differencesin the rate of restenosishave been found in other studies,and are difficult to explain.6J3-15

NOVEMBER 1,1993

Recoil and restenosis: Restenosis(definedas final diameterstenosis>50%) was seenmore often in lesions that had greaterrecoil. This is in agreementwith Kuntz et al3 who showed that the larger the immediate post-

procedurediameter,the less the clinical restenosisrate. For clinical purposesthe definition of restenosisis based on the tinal diameterstenosisachieved,but the process of restenosisshould be describedmore accuratelyby a

1ABLE IV Angiographic Predictors of Acute Recoil Based on Tertile Subgroup Analysis Immediate Recoil

Lesion diameter (mm) Before angioplasty <0.53 >0.53, < 1.06 >1.06 After angioplasty <2.63 >2.63, <3.1 >3.1 Follow-up 11.31 > 1.10, <2.63 >2.63 Normal artery diameter (mm) <2.9 >2.9, <3.43 > 3.43 Balloon diameter (mm) <2.9 >2.9 <3.17 >3.17 Ratio* <0.97 > 0.97, < 1.03 >1.03 Lesion length (mm) <8.1 >8.1, <13.1 > 13.1 Diameter changes Potential gain Absolute (mm) < 1.85 > 1.85, <2.6 >2.6 Relative (%) <62 >62, <81 >81 Actual gain Absolute (mm) < 1.58 > 1.58, <2.13 >2.13 Relative (%) <50 >50, <70 >70 Late loss Absolute (mm) O.Ol, <1.06 > 1.06 Relative (%) l, <35 >35

Number of Patients

Absolute (mm)

250 184 162

0.47 2 0.70 0.38 + 0.61 0.38 + 0.60

183 211 202

0.96 f 0.74 0.33 f 0.43 0.03 k 0.31

118 123 156

0.54 f 0.76 0.41 f 0.51 0.34 zi 0.58

187 191 218

0.50 + 0.61 0.36 2 0.54 0.40 k 0.74

186 240 170

0.27 k 0.57 0.39 A 0.56 0.62 z 0.76

187 255 154

0.17 zk 0.57 0.34 k 0.56 0.84 k 0.65

276 115 205

0.45 k 0.62 0.40 k 0.69 0.39 i 0.63

199 191 206

0.28 -+ 0.50 0.36 it 0.60 0.60 I 0.75

200 194 202

0.23 r 0.51 0.37 f 0.59 0.65 k 0.73

179 226 191

0.90 r?r 0.76 0.33 2 0.46 0.07 2 0.39

211 181 204

0.82 +- 0.77 0.33 rt 0.46 0.08 2 0.34

148 110 139

0.59 +- 0.76 0.39 2 0.56 0.27 -t 0.46

148 114 135

0.59 2 0.76 0.36 k 0.56 0.29 i. 0.46

P Value

Relative (%)

<0.24

P Value

<0.09 16 + 25 12 2 19 12 + 19

< 0.001


<0.03


<0.09

< 0.001 20 i 26 12 fc 17 11220


<0.02 12 AZ24 13 + 18 18 + 23

‘Co.001


<0.55

<0.15 16 2 23 12 t 20 13 + 20


10.001 10 f 17 13 f 22 19 + 24







10.001 19 + 25 12 2 17 10 F 16

*See legendto Table I for explanation. Valuesare mean f SD.

RECOIL AFTER ANGIOPLASTY 1023

TABLE V Angiographic

Analysis

of Lesions According LAD (n = 296)

Lesion diameter (mm) Before angioplasty After angioplasty Follow-up* Normal artery diameter (mm) Balloon diameter (mm) Ratio? Lesion length (mm) Diameter changes Potential gain Absolute (mm) Relative t%) Actual gain Absolute (mm) Relative t%) Immediate loss (recoil) Absolute (mm) Relative t%) Late loss* Absolute (mm) Relative (%I

0.82 2.57 1.79 3.09 3.05 1.00 9.9

f f + + k f f

to Location

cx (n = 146)

0.56 0.72 1.06 0.52 0.46 0.13 5.5

0.85 2.74 1.96 3.06 3.04 1.01 9.4

f t f + + k ?

in Different RCA (n = 154)

0.60 0.61 1.07 0.53 0.49 0.12 5.6

0.90 2.84 2.10 3.37 3.25 0.97 11.8

k 0.59 k 0.67 f 1.11 f 0.53 t 0.52 + 0.12 zk 6.2

Arteries P Value

NS
NS
2.22 k 0.61 73 + 20

2.20 2 0.70 73 2 22

2.34 2 0.74 70 + 20

NS NS

1.75 k 0.83 57 -+ 26

1.89 e 0.76 62 -t 23

1.94 t 0.83 58 +- 23

NS NS

0.48 f 0.70 16 f 24

0.31 k 0.48 11 f 16

0.40 2 0.64 12 ? 20

<0.05 <0.02

0.76 ZL 1.09 25 2 35

0.78 2 0.99 26 2 32

0.72 f 1.10 22 f 33

NS NS

*Data are available for 213, 89 and 95 lesions in the left anterior, left circumflex and right coronary arteries, respectively. tSeeTable I for explanation. Valuesare mean + SD. Cx = circumflex artery; LAD = left anterior descending artery: RCA = right coronary artery.

Absolute 1 I-----

Relative

(mm)

(46) , 20

I

0.6 -

15

I

0.6 -

10 0.4 -

FGURE 1. The influence of arterial stretch, measured by balloon to normal artey size ratio, oa the immediate recoil after balloon angioplasty. The 3 bars represent low, middle (Mid) and high groups of arterial stretch.

5 0.2 -

~0

OMid

High

Balloon / Normal artery

continuousvariable that measuresthe late loss of luminal diameter after angioplasty.9,16 This late loss in diameterwas smaller in lesions with larger immediate recoil. Beatt et all6 similarly showedthat the less the residual stenosisafter angioplasty,the higher the late loss in diameter.The late loss in luminal diameter is either due to cellular proliferation or to chronic recoil.17Cellular proliferation is triggeredby dissectionof the arterial wall. Potentially,arteries that respondto dilatation with more stretch (and more recoil) have less damageto the wall of the artery and thus respond with less cellular proliferation. Alternatively,it is possiblethat arteriesthat recoil more, immediately after the angioplasty,undergo less late recoil. 1024

THE AMERICANJOURNALOF CARDIOLOGY VOLUME72

Summary: This study shows that immediate recoil of the artery after balloon dilatation is responsiblefor residual stenosisafter balloon angioplasty.The recoil is an elastic phenomenonand it is determinedmainly by the amount of stretch of the artery. Becausethe immediate postangioplastydiameter is the best predictor for long-term results, strategiesthat will minimize recoil may be important in decreasingthe clinical restenosis rate. However, this report also shows that the late loss of luminal diameter is more prominent in arterieswith less initial recoil (better initial angioplastyresult). 1. Rensing BJ, Hermans WR, Strauss BH, Semys PW. Regional differences in elastic recoil after percutaneous translumiml coronary angioplasty: a quantitative mgiographic study. J Am Co/l Car&[ 1991;17:34B-38B.

NOVEMBER1,1993

2. Rensing BJ, Hermans WR, Beatt KJ, Laarman GJ, Suryapranata H, van den Brand M, de Feyter PJ, Sermys PW. Quantitative angiographic assessmentof elastic recoil after percutaneoustransluminal coronruy angioplasty. Am J Cardiol1990;66: 103%1044. 3. Kuntz RE, Stian RD, Levine MJ, Reis GJ, Diver DJ, Bairn DS. Novel ap preach to the analysis of restenosis after the use of three new coronary devices. J Am CON Cardiol 1992; 19: 1493-1499. 4. Califf RM, Fortin DF. Frid DJ, Harlan W R III, Ohman EM, Bengtson JR, Nelson CL, Tcheng JE, Mark DB. Stack RS. Restenosis after coronary angioplasty: an overview. J Am C O N Cardiol 1991;17:2B-13B. 5. Holmes DR, Schwartz RS, Webster MWI Coronary restenosis: what have we learned from angiogmphy? .I Am Coil Car&[ 1991; 17:14B-22B. 6. Leimgmber PP. Roubii GS, Hollman J, Cotsonis GA, Meier B, Douglas JS, King SB III, Gruentzig AR. Restenosis after successful coronary angioplasty in patients with single vessel disease. Circu2afion 1986;73:71&717. 7. Hiishfeld JW, Schwartz JS, Jugo R, Macdonald RG, Goldberg S, Savage MP, Bass TA, Vetrovec G, Cowley M, Taussig AT, Whitworth HB, Margolis JR, Hill JA, Pepine CJ. Restenosis after coronary angioplasty: a multivariate statistical model to relate lesion and procedure variable to restenosis. J Am Co/l Cardiol 1991;18: 647-656. 8. Nobuyoshi M, Kiiura T, Nosaka H, Mioka S, Ueno K, Yokoi H, Hamasaki N, Horiochi H, Ohisbi H. Restenosis after successful percutaneous tmnsluminal coronary angioplasty: serial angiographic follow-up of 299 patients. .I Am Co/l Cardiol 1988;12:6&622. 9. Rensing BJ, Hermans WRM, Deckers JW, de Feyter PJ, Tijssen JGP, Sermys PW. Lumen narrowing after percutaneoustransluminal coronary balloon angioplasty follows a near gaussian distibution: a quantitative angiographic study in 1445 suc-

cessfully dilated lesions. J Am Co/l Car-dial 1992;19:939-945. 10. Roubin GS, Douglas JS Jr, King SB III, Lin S, Hutch&on N, Thomas RG, Gruentzig AG. Influence of balloon size on initial success,acute complications, and restenosis after percutaneous transluminal coronary angioplasty: a prospective randomized study. Circulation 1988;78:557-565. 11. Hallon DA, Sapoznikov D, Lewis BS, Go&man MS. Localization of lesions in the coronary circulation. Am J Cardiol 1983;52:921-926. 12. FischeU TA, Derby G, Tse TM, St&us ML. Coronary artery vasoconshiction routinely occurs after percutaneous tmnsluminal cororxuy angioplasty: a quantitative angiographic analysis. Circu&ion 1988;78:1323-1334, 13. Vandormael MG, Deligonul U, Kern M, Harper M, Presant S, Gibson P, G&m K, Chaitman BR. Multilesion coronary angioplasty: clinical and angiograpbic follow-up. J Am Coil Cmdiol 1987;10:24&252. 14. Fishman RF, Kuntz RE, Carrozza JP, Miller MJ, Senerchia CC, Schnitt SJ, Diver DJ, Satian RD, Bairn DS. Long term result of directional coronary atherectomy: predictors of restenosis. J Am Co/l Cardiol 199220: 1101-l 110. 15. Carrozza JP, Kuntz RE, Levine MJ, Pomerantz RM, Fishman RF, Mansour M, Gibson CM, Senerchia CC, Diver DJ, S&m RD, Bairn DS. Angiogmphic and clinical outcome of intracoronary stenting: immediate and long-term result from a large single-center experience. J Am Co/l Cardiol 1992;20:328-337. 16. Beatt KJ, Sermys PW, LulJten HE, Rensing BJ, Suyapranata H, de Feyter PJ, van den Brand M, Lawman GJ, Roelandt J. Restenosis after coronary angioplasty: the paradox of increased lumen diameter and restenosis..I Am Coil Cwdiol 1992; 19: 258-266. 17. Wailer BF, Pinkerton CA, Orr CM, Slack JD, VanTassel JW, Peters T. Restenosis 1 to 24 months after clinically successful coronary balloon angioplasty: a necropsy study of 20 patients. J Am Co0 Cardiol 1991;17:58B-70B.

RECOILAFTERANGIOPLASTY 1025