Usefulness of intracoronary stenting in acute myocardial infarction

Usefulness of Intracoronary Stenting Acute Myocardial Infarction

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Michel R. Le May, MD, Marino Labinaz, MD, Rob S.B. Beanlands, MD, Louise A. Larambe, MD, Edward R. O’Brien, MD, Jean-FranGois Marquis, MD, William L. Williams, MD, Khalid Al-Sadoon, MD, Richard F. Davies, MD, Sharon Ann Kearns, RN, Helen L. Johansen, PhD, and Lyall A. Higginson, MD Data on the feasibility, safety, and clinical outcome of intracoronary stenting in acute myocardial infarction (AM) are limited. This study examined the immediate angiographic results and the early and late outcomes in 32 patients who had stenting during AMI. Coronary angiograms recorded at the time of stenting were reviewed with quantitative measurements obtained on the “target” coronary lesion before and after stenting. Immediate angiographic success was achieved in 30 patients (94%). The minimal luminal diameter increased from 0.36 -C 0.37 to 2.58 2 0.41 mm (p
emia. Although thrombus at the infarct-related coronary lesion was initially detected in 41% of the patients, its presence was not associated with adverse procedural outcome. Only 1 patient had persistent thrombus after stenting, which resolved with intracoronary urokinase. At a mean follow-up of 6.1 2 4.1 months, there was 1 additional cardiac death, and no patient had AMI or required repeat coronary angioplasty or bypass; among the 29 survivors, 86% were free of angina. Thus, intracoronary stenting of the infarct-related artery in the setting of AMI is associated with excellent immediate angiographic success and a favorable clinical outcome, and remains an option even in the presence of thrombus. (Am J Cardiol 1996;78:148-152)

revious studies of intracoronary stenting have P excluded patients with acute myocardial infarction (AMI). The BENESTENT (Belgium and Neth-

longed ischemic chest discomfort associated with any one of the following 3 criteria: ( 1) elevation of creatinine kinase to >2 times the upper limit of normal and a positive MB fraction, (2) persistent STsegment elevation of > 1 mm (0.1 mV) in 2 or more contiguous electrocardiographic leads, and (3 ) the appearance of new pathologic Q waves of at least 0.04 seconds’ duration. AM1 was defined as “evolving” if the interventional procedure was performed within 24 hours of presentation and there was evidence of ongoing ischemia. A “recent” AM1 was defined as AM1 that occurred within 2 to 7 days of the interventional procedure. Patients were excluded if coronary angioplasty had been done on the infarct-related artery within 3 months of the index AM1 or if the culprit lesion involved a saphenous vein graft. Baseline clinical demographics of the study patients and in-hospital complications were obtained by chart review. Follow-up was obtained by contacting all patients either at clinic visits or by telephone interviews. Stent implantation: In all cases, only the infarctrelated artery was stented. Stenting was performed after unsuccessful coronary angioplasty in 28 of 32 patients: 24 because of high-grade residual stenosis and 4 after abrupt closure. Stenting was done as the primary procedure in 4 patients. All patients received Palmaz-Schatz articulated stents (Johnson & Johnson, Interventional Systems, Wasen, New Jersey), and 1 patient who required more than 1 stent also received a Wiktor stent (Medtronic Inc., Minneapolis, Minnesota). When necessary, a half-length stent was obtained by cutting a 1.5mm PS153 stent at the articulation.’ Nine patients required > 1 stent.

erlands Stent) trial included only stable patients with a single discrete lesion free of intracoronary thrombus.’ Whereas 47% of the stented patients in the STRESS (Stent Restenosis Study) trial had unstable angina at baseline, patients with AM1 within the previous 7 days were excluded, and only 2% of patients had definite angiographic evidence of thrombus.* In the absence of evidence to the contrary, stenting in AM1 has been avoided because of the perceived increased risk of thrombotic complications due to insertion of a metallic device in a thrombogenic environment.3 To date, only a few case reports”-6 and 1 series of 10 patients7 have been published supporting the utility of stents in the setting of AMI. To determine whether the thrombogenic risk is indeed high within the first week of AMI, we reviewed our experience with intracoronary stenting in this setting.

METHODS Patient selection: A total of 489 patients were treated with intracoronary stenting at the University of Ottawa Heart Institute from January 1994 through September 1995. Of these, 32 patients received intracoronary stents in the setting of AMI, defined as proCare Unit and Interventional Research Group, From the Corona Division of Cardio 7oav, Universitv of Ottawa Heart Institute, Ottawa, Ontario, Canada. &: Beanland; is a research scholar supported by the Medical Research Council of Canada, Ottawa, Canada. Dr. O’Brien is a research scholar supported by the Heart and Stroke Foundation of Canada. Manuscript received November 24, 1995; revised manuscript received and accepted Februay 5, 1996. Address for reprints: Michel R. Le May, MD, Ottawa Heort Institute, 1053 Carling Avenue, Ottawa, Ontario, Canada Kl Y 4E9.

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A total of 41.5 Palmaz-Schatz stents were inserted: 40.5 PS153s (15 mm) and 1 PS204C (18 mm); halflength stents were inserted in 7 patients. All patients received aspirin ( 160 to 325 mg) before the procedure and 325 mg/day thereafter. Hepat-in was given during the procedure to maintain the activated clotting time >300 seconds. Patients also received nitroglycerin by intravenous and/or intracoronary route. Dextran was not used for any patient. Only 1 patient received intracoronary thrombolytic agents. Coronary angioplasty was performed in a standard fashion. After dilatation, the stent was mounted on the balloon, hand-crimped by the operator, and deployed at the coronary angioplasty site. In 30 patients, the stent was further expanded at higher atmospheric pressure using a noncompliant balloon, and in 27, balloon pressure used within the stent was 2 14 atm. Intravascular ultrasound was not routinely used. After the procedure, patients returned to a monitored unit. In most patients, the arterial sheath was removed within 24 hours. Heparin was stopped 4 hours before sheath removal, and restarted 4 hours afterward if the patient was prescribed warfarin. For the 14 patients who received warfarin therapy, the International Normalized Ratio was maintained between 2.5 and 3.5 for 1 month. Influenced by new reports of intracoronary stenting without the use of warfarin,9%‘0we prescribed this medication to fewer patients enrolled later in the study. Twenty-nine patients received ticlopidine 250 mg orally twice daily for 1 month, beginning on the day of the procedure. One patient received dipyridamole. Data analysis: All 32 coronary angiograms recorded at the time of stenting were reviewed. The lesions before coronary angioplasty were classified according to the modified American College of Cardiology/American Heart Association criteria.” Arterial patency was assessed before coronary angioplasty and after stenting using the Thrombolysis in Myocardial Infarction (TIMI) criteria. I2 All angiograms were reviewed for the presence of intracoronary thrombus before coronary angioplasty and after intracoronary stenting. Thrombus was defined as an intraluminal filling defect at the site of the stenosis seen in >l view. In the case of total occlusions, thrombus was reported if a convex contrast outline associated with staining was seen on angiography. l3 Quantitative measurements were obtained at the University of Ottawa Heart Institute using a customized Siemens Digitron 3.61 analytic program (Erlangen, Germany). The technique has been reported previously and validated by Morton et a1.14Briefly, calibration markers 10 cm apart and a central marker were embedded in a transparent plate placed over the image intensifier tube, allowing determination of a calibration line and calculation of vessel diameters in mm. An Arripro projector (Munich, Germany) was used to magnify the image optically 2.8 times. The single projection that best demonstrated the tarCORONARY

get lesion at end diastole was selected throughout the study, converted to video, and digitized. The validity of the technique was assessedby filming dye-filled Plexiglas@ channels, yielding a test-retest SD of 0.054 mm. In the present study, the following measurements were obtained: (1) reference vessel diameter, (2) minimal luminal diameter, and (3 ) maximal balloon diameter used for stent deployment. The percent diameter stenosis was calculated using the minimal and reference vessel diameters. The reference vessel diameter was defined as the average of the proximal and distal reference diameters measured just outside the stented area.2In ostial lesions, only a distal reference diameter was measured, whereas in total occlusion, only a proximal reference diameter was measured. Stent recoil was calculated as the difference between the maximal measured balloon diameter during stent deployment and the minimal luminal diameter after the procedure, divided by the maximal measured balloon diameter. Immediate gain was defined as the difference between the minimal luminal diameters before and after the procedure. Angiographic successwas defined as a patent vessel with TIM1 III flow and a final residual stenosis <50%. Procedural success was defined as angiographic success in the absence of death, reinfarction, repeat coronary angioplasty of the target vessel, or coronary artery bypass surgery during the hospital period. Reinfarction was defined as recurrent chest discomfort compatible with ischemia, associated with a new increase in creatine kinase of >2 times the upper limit of normal. Late clinical follow-up was carried out at hospital clinic visits or by telephone interviews for all patients. The following outcomes were recorded: death, reinfarction, need for coronary artery bypass surgery, need for repeat coronary angioplasty, and angina1 status using the Canadian Cardiovascular Society Classification. Follow-up angiograms were recorded in 11 patients. Restenosis was defined as a >50% diameter stenosis at the stent site on follow-up angiography. Statistical analysis: Results are reported as mean ?K SD. Pre- and postprocedure differences were assessed by the Wilcoxon test. Fisher’s exact test was used to compare categoric variables. A p value <0.05 was considered statistically significant. RESULTS Patient characteristics: The demographics of the study population are listed in Table I. Intravenous thrombolytic agents were given immediately to 19 patients (59% ) at the time of infarction. New pathologic Q waves were noted in 10 of 13 patients with evolving AM1 and in 10 of 19 with recent AMI. Thirteen patients with AM1 received stents within 14 hours of onset of AMI, and the 6 patients presenting with cardiogenic shock were in this group. Direct coronary angioplasty was performed in 7 patients and rescue in 6. For the 19 patients with recent .AMI, coronary angioplasty was performed for angina after

ARTERY DlSEASE/?NTRACORONARY

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(94%): a final diameter stenosis of GO% was achieved in all patients; however, 2 patients had Male gender 26 (81%) TIM1 II flow at the end of the procedure. In the 13 532 12 Age (Y) patients stented within 14 hours of AMI,.the minimal Range 27-74 luminal diameter increased from 0.12 + 0.25 to 2.73 Diabetes mellitus 1 (3%) + 0.43 mm (p 50% in diameter After stenting, no patient experienced reinfarction 1 18 (56%) or required coronary artery bypass grafting. Two pa2 7 (22%) tients underwent repeat coronary angioplasty. One 3 6 ( 19%) patient presented with recurrent chest pain the day Left main 1 (3%) Target coronary artery after stent implantation and was found to have an Left anterior descending 15 (47%) occluded stent site, which was easily redilated with Right 12 (38%) a larger balloon at a higher atmospheric pressure. A Left circumflex 4 (12%) second patient in whom coronary angioplasty was Left main 1 (3%) complicated by a long dissection had recurrent inhospital angina. At repeat angiography, the. stented .. 7. AMI. The distribution of patients as a function of site was patent, but a second stent was placed distally to cover a portion of the original dissection. time to stenting is displayed in Figure 1. Six patients presented with cardiogenic shock; all Qualitative angiographic results: Most initial coronary lesions were type B (41% Bl, 31% B2), required inotropic support and 4 required intraaortic whereas 22% were type A, 6% were Cl, and none balloon counterpulsation to maintain a systolic blood were C2. Table II summarizes the TIM1 flow grades pressure >80 mm Hg. Two of these 6 patients died before and after stenting. After stent placement, the and represent the only in-hospital deaths in this number of patients with TIM1 III flow improved study. One of the 2 patients had a postmortem anfrom 44% to 94% (p
Demographics

of the 32 Study Patients

6

FIGURE 1. Distribution of patients stented during the first 7 days of acute myocardial infarction (AM): 13 patients had stenting within 14 hours of acute myocardial infarction and 19 patients between days 2 and 7. 0

2

4

6

8

10

12

14

12

3

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TABLE II Qualitative

Angiographic

Characteristics

of the 32 Patients Before TIMI

After Stenting

Stenting

flow

0 I

12 (38%) 3 (9%)

II

3 (9%)

Ill

14 (44%)

0 2 (6%) 30

13 (41%)

Thrombus * Resolved

0

after infusion

TIM1 = Thrombolysis

of intracoronory

in Myocordiol

(94%) 1 (3%)*

urokinase.

Infarction

trial.

formed successfully after a suboptimal coronary angioplasty result. Follow-up angiography was performed either before or after discharge in the 4 survivors of cardiogenic shock, and, in each case, the stented segment was widely patent. Vascular complications occurred in 1 patient who developed a small arteriovenous fistula, which subsequently closed spontaneously. Two patients required blood transfusion. After intracoronary stenting. the median length of hospital stay for the entire study group was 7 days; however, in the subset of patients who were not prescribed warfarin, the median was 4 days. Discharge follow-up: The mean follow-up period was 6.1 2 4.1 months. The patient who underwent stenting of an occluded, unprotected left main artery had repeat angiography at 4 months demonstrating no evidence of restenosis. However, he developed progressive symptoms of heart failure and died after heart transplantation 8 months after intracoronary stenting. No patient experienced reinfarction or required repeat coronary angioplasty or bypass surgery. Follow-up coronary angiography was performed in 11 patients at a mean of 5.1 ? 3.8 months. All stented vessels were patent and free of restenosis. Two patients with TIMI II flow immediately after stenting were free of cardiac events at follow-up; 1 had a repeat angiogram showing restored TIMI III flow. Of the 29 patients who remained free of major cardiac events, 25 ( 86%) were free of angina and 4 ( 14%) had Canadian Cardiovascular Society class I or II angina.

tients required blood transfusion (7% ). After discharge, there was only 1 additional death, and 86% of the surviving patients were free of angina. Preexisting intracoronary thrombus is associated with an increased risk during coronary angioplasty.‘j-2’ Other investigators have suggested that prerequisites for successful stenting in the setting of AMI are a minimal amount of thrombus in the infarct-related artery and liberal use of intracoronary thrombolytic therapy.‘.’ Ahmad et al7 recently reported on 10 patients who received intracoronary stents after unsuccessful coronary angioplasty at the time of AMI. Six of the 10 patients received intracoronary thrombolytic agents during the procedure, and all received warfarin. TIM1 III flow was restored in all 10 patients after stent placement. Clinical reocelusion occurred in 3 patients at 6 hours, 24 hours, and 17 days, respectively, after the initial procedure. Mean pressures used in the stent were reported as 8.8 atm. In our study, thrombus was present in 41% of patients before stentin g: however, only 1 patient received intracoronary urokinase after stenting. No patient had angiographic evidence of thrombus at the end of the procedure. Of note, warfarin was prescribed to only 44% of these high-risk patients. The presence of thrombus on the angiogram before coronary angioplasty did not adversely affect the outcome after stenting. This finding and the high success rate in the current study may be due to a number of factors. One factor that may be particularly important was the use of high balloon pressures ( 15.6 +- 3.1 atm) to assure adequate stent deployment, as proposed by Nakamura et a1.22In our practice, we currently deploy all stents with a noncompliant balloon at pressures 214 atm. The good overall outcome in the present study suggests that the routine use of intracoronary thrombolytics may not be necessary. They may, however, be beneficial in some patients with persistent intracoronary thrombus. Study limitations: This was a retrospective study reviewing 32 patients treated with stent insertion in the setting of evolving or recent AMI. The number of patients was small, and most had failed other treatTABLE Ill Quantitative

Angiography

Data on the 32 Study

Patients

DISCUSSION Intracoronary stenting in the setting of. AM1 has generally been avoided because of the perceived increased risk of local thrombotic complications.’ To our knowledge, this study describes the largest published series of patients receiving stents in the setting of evolving and recent AMI. Angiographic success was high at 94%, and the minimal luminal diameters achieved in our patients parallel those reported in the BENESTENT and STRESS trials.‘-’ The in-hospital procedural outcome was favorable, with an 8 1% rate of success. Stent occlusion occurred in only 1 patient, and the 2 deaths occurred in patients presenting with severe cardiogenic shock. The number of vascular complications was small (3%), and few paCORONARY

Before Stenting Reference

vessel

diameter MLD

2.82

t

0.64

2.96

k 0.57

0.36

!I 0.37

2.58

k 0.41

p Value NS

(mm]

[mm)

Percent

After Stenting

diameter

85k

16

11 k

15


stenosis Maximal balloon dilatation (mm]

3.24

f

Maximal

15.6

k 3.1

balloon

pressure Range Immediate

(atm) gain

2.23

(mm1 Recoil (?A) MLD = minimal

ARTERY DISEASE/INTRACORONARY

0.32

19.9 luminal

8-20 t 0.58 2

12.2

diameter

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ments including thrombolysis and traditional balloon angioplasty. Randomized trials comparing primary stenting with other treatment modalities will be needed to define the role of stenting as an initial strategy in AM1 patients. Second, long-term angiographic patency could not be assessedformally because follow-up angiography was not available in all patients. Acknowledgment: The authors are indebted to Laurie Jozwiak for performing the QCA measurements and to Suzanne Despatie for her secretarial assistance.

1. Sermys PW, Jaegere P, Kiemeneij F, Macaya C, Rutsch W, Heyndrickx G, Emanuelsson H, Marco J, Legrand V, Mateme P, Belardi J, Sigwxt U, Colombo A, Goy JJ, Heuvel P, D&an J, Morel M, for the BENESTENT Study Group. A comparison of balloon-expandable-stat implantation with balloon angioplasty in patients with coronary artery disease. N Engl .I Med 1994;8:489-495. 2. Fischman DL: Leon MB, Bairn DS, Schatz RA. Savage MP, Penn I, Detre K, Veltri L, Rica D, Nobuyoshi M, Cleman M, Heuser R, Almond D, T&stein PS, Fish D, Colombo A, Brinker J, Moses J, Schaknovich A, Hirshfeld J. Bailey S, Ellis S, Rake R, Goldberg S. A randomized comparison of coronary-stat placement and balloon angioplasty in the treatment of coronary artery disease. N Engl J Med 1994;8:496-501. 3. Semys PW, Strauss BH, Beatt KJ, Bertrand ME. Puel J, Rickards AF, M&r B, Goy JJ, Vogt P. Kappenberger L, Sigwart U. Angiographic follow-up after placement of a self-expanding coronary-artery stat. N Engl J Med 1991;324:13-17. 4. Cannon AD, Roubin GS, Macander PJ, Agrawal SK. Intracoronary staring as an adjunct to angioplasty in acute myocardial infarction. J Invas Cardiol 1991;3:255-258. 5. Wong PHC, Wong CM. Intracoronary stenting in acute myocardial infarction. Cathet Cardiovasc Diagn 1994;33:39-45. 6. Walton AS, Oesterle SN, Yeung AC. Coronary artery stenting for acute closure complicating primary angioplasty for acufe myocardial infarction. Cathet Cardiovnsc Diagn 1995;34:142-146. 7. Ahmad T, Webb JG, Carere RR, Dodek A. Coronary stenting for acute myocardial infarction. Am J Cardiol 1995;76:77-80. 8. Colombo A, Hall P, Thomas J, Almagor Y, Finci L. Initial experience with the disarticulated (one-half) Palmaz-Schatz stat: a technical report. Cathet Cardiovasc Diagn 1992;25:304-308.

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9. Colombo A, Hall P, Almagor Y, Maiello L, Gaglione A, Nakamura S, Borrione M, Goldberg SL, Finci L, Tobis J. Results of intravascular ultrasound guided coronxy stating without subsequent anticoagulation. .I Am Co0 Cardial 1994;23:335A. 10. Mehan VK, Salzmann C, Kaufmann U, Meier B. Coronary stenting without anticoagulation. C&her Cardiovasc Diagn 1995;34:137-140. 11. Ellis SG, Vandormael MG, Cowley MG, DiSciascio G, Deligonul IJ, Top01 EJ, Bulle TM. Coronary morphologic and clinical determinants of procedural outcome with angioplasty for multivessel coronary disease. Circularion 1990;82:1193-1202. 12. Chesebro JH, Knatterud G, Roberts R, Borer J, Cohen LS, Dale” J. Dodge HT, Francis CK, Hillis D, Lndbrook P, Ma&is JE, Mueller H, Passamini ER. Powers ER, Rae AK, Robertson T, Ross A, Ryan TJ, Sobel BE. Willerson J, Williams DO, Zaret BL, Braunwald E. Thrombolysis in Myocardial Infarction (TIMI) Trial, phase 1: a comparison between intravenous tissue plasminogen activator and intravenous streptokinase. Circtrlafion 1987;76: 142-154. 13. Mooney MR, Mooney JF, Goldenberg IF, Almquist AK, Van Tassel R4. Percutaneous transluminal coronary angioplasty in the setting of large intmcoronary thrombi. .Im J Cardiol 1990;65:427-43 1. 14. Morton BC, Gill JB, Robats RS, Larocque BG, Jozwiak LA, Cairns 5.4. Does it matter how coronary projections are combined to assess restenosis following PTCA? Inr J Carddiac Imag 1995;ll: 145-149. 15. Ellis SG, Roubin GS, King SB III. Douglas JS Jr, Weintmub WS, Thomas RG, Cox WR. Angiogmphic and clinical predictors of acute closure after native vessel coronary angioplasty. Circrrlation 1988:77:372-379. 16. Myler RK, Shaw RE, Stertzer SH, Hechr HS. Ryan C, Rosenblum J, Cumberland DC, Murphy MC, Hansel1 HN. Hidalgo B. Lesion morphology and coronary angioplasty: current experience and analysis. J Am Co// Cnrdiol 1992;19:1641-1652. 17. Savage MP, Goldberg S, Hirshfeld JW’, Bass TA. MacDonald RG, Margolis JR, Tanssig AS, Vetrovec G, Whitworth HB, Zalewski A, Hill 54. Cowley M, Jugo R, Pepine CJ. Clinical and angiographic determinants of primary coronary angioplasty success. JAm Co0 Cardiol 1991:17:22-28. 18. Mabin TA, Holmes DR Jr, Smith HC, Vlietstra RE. Bove AA, Reeder GS, Chesebro JH, Bresnahan JF, Orszulak TA. Intracoronary thrombus: role in COTonary occlusion complicating percutaneous coronary angioplasty. J Am COIL Cardiol 1985:5:198-202. 19. Sugme DD, Holmes DR Jr, Smirh HC, Reeder GS, Lane GE, Vlietstra RE, Bresnahan JF, Hammes LN, Piehler JM. Coronary artery tbrombus as a risk factor for acute vessel occlusion during percutaneous transluminal coronary angioplasty: improving results. Br Hemt J 1986;56:62-66. 20. Deligonul U. Gabliani GI, Caralis DC, Kern MJ, Vandormael MG. Percutaneous transluminal coronary angioplasty in patients with inuacoronary thrombus. Anz J Cardiol 1988;62:474-478. 21. Tan K, Sulke N, Taub N, Sowton E. Clinical and lesion morphological determinants of coronary angioplasty success and complications: current experience. JAm Co11 Cardiol 1995;25:855-865. 22. Nakamura S, Colombo A, Gaglione A, Almagor Y, Goldberg S, Maiello L, Finci L, Tobis JM. Intracoronary ulbrasound observation during stat implantation. Circrdation 1994;89:2026-2034.

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