BRIEF REPORTS

Complications of Percutaneous Transluminal Coronary Angioplasty in Patients Convalescing from Acute Myocardial Infarction Joseph Lindsay, Jr., MD, Venugopal M. Reddy, MBBS, Ellen E. Pinnow, MS, and August0 D. Pichard, MD

D isagreement exists with regard to the role of percu- taneous transluminal coronary angioplasty (PTCA)

in patients convalescing from acute myocardial infarction (AMI). Routine PTCA within the tist few days after thrombolytic therapy offers no benefit beyond that re- sulting from thrombolysis. l-3 Nevertheless, many physi- cians believe that even patients in stable condition are best served by diagnostic angiography and appropriate revascularization at some later point in their convales- cence.4 However, there is evidence that the risk of death and major complications in such patients is greater than is true for PTCA performed outside the setting of AML5Jj The Treatment of Post Thrombolytic-Stenoses Study Group encountered a mortality of 2.1% in stable patients treated electively with PTCA 4 to 14 days after AMI, a figure substantially greater than that in patients with no recent AMI.5,6 Few data are available compar- ing the procedure-related morbidity and mortality asso- ciated with PTCA in contemporaneously treated patients with and without recent AMI. To provide insight into this issue, we compared results in those with AM1 within 30 days of the PTCA with those with no such history.

The operating cardiologist or an assistant completed a procedural report form for 5,042 procedures per- formed between January 1, 1991 and December 31, 1992 in the cardiac catheterization laboratory of the Washington Hospital Center. Baseline clinical features and procedural events were recorded. Concurrent hos- pital follow-up by chart review was available for 3,877 patients (76.9%). The acquisition of follow-up data de- pended upon the availability of the research assistant and did not introduce a bias with regard to the frequency of baseline or procedural variables. The age and sex dis- tribution did not direr between the 2 groups, nor did the frequency of AMI within 30 days, unstable angina, mul- tilesion PTCA, device use, and type C lesion. Prior coro- nary artery bypass surgery was slightly more common in those who were followed up. Of the 3,877 patients, 89 treated during an evolving myocardial infarction were excluded from further analysis, as were the 63 for whom the procedure form did not clearly indicate whether an AMI had occurred or whether the patient was stable or unstable. Thus, we report the outcome in 3,725 PTCAs.

The ages of the patients were expressed as mean + SD and were compared by means of an analysis of vari- ance. Discrete variables were compared by means of contingency tables, and chi-square analysis by means of

From the Section of Cardiology, the Washington Hospital Center, 110 Irving Street NW, Washington, D.C. This report was supported in part by a grant from the Medlantic Research Institute, Washington, D.C. Manuscript received July 26, 1993; revised manuscript received and accepted November 18, 1993.

the Yates correction. Fisher’s exact test was used when appropriate. Stepwise logistic regression was carried out using the SAS computer statistical package.8

PTCA was undertaken in 791 patients (21.2%) who had sustained an AMI within the preceding 30 days. Of that group, 299 (37.8%) were judged to be stable and 492 (62.2%) unstable at the time of PTCA. No AMI had occurred in the 30 days before angioplasty in 2,934 pa- tients (78.8%). Of these, 1,121 patients (38.2%) were re- garded as stable and 1,813 (61.8%) as unstable.

Several baseline characteristics in the patients who had sustained an AMI in the 30 days before PTCA dif- fered from those in the group who had not (Tables I to III): (1) Those with recent AMI were slightly younger. This difSerence in age was present in both the stable and the unstable subgroups. (2) A history of prior coronary artery bypass surgery was obtained less than half as of- ten in those with recent AMI. This, too, was true for both the stable and the unstable subgroups. (3) In patients with recent AMI, the most complex lesion targeted for angioplasty was less often a type C lesion, as defined by the American College of CardiologylAmerican Heart As- sociation Task Force.9 This difSerence was sign@cant only in the subgroup regarded as stable at the time of PTCA. (4) Patients with recent AMI had multilesion PTCA less often. Again, this diference was significant only in stable patients. (5) A device other than a balloon was used only half as often in patients with recent AMI in both the stable and unstable subgroups.

Of the 791 patients who underwent PTCA within 30 days of AMI, 17 (2.1%) died in the hospital. Of the 2,934 who had not had AMI, 15 (OSqo) died. This difference is highly signi$cant (p <O.OOl, odds ratio 4.4,95% con- fidence interval (CI] 2.0, 9.1).

The d@erence in hospital mortality persisted when patients were grouped with regard to their stability at

TABLE I Characteristics of All Patients

AMI ~30 Days No Yes p Value

Number of patients 2,934 791 Mean age (years) (SD) 62.7 (11.2) 61.1 (11.9) <O.OOl r 65 years (%I 1,380 (47.0) 331 (41.8) 0.011 Women (%) 844 (28.8) 233 (29.5) 0.737 Prior CABG (%) 847 (28.9) 94 (11.9) <O.OOl 2 2 lesions targeted (%) 1,048 (35.7) 231 (29.2) <O.OOl Type C lesion targeted (%) 1,630 (55.6) 400 (50.6) 0.02 1 Device used (%) 1,157 (39.4) 167 (21.1) <O.OOl

Death (%) 15 (0.5) 17 (2.1) <O.OOl Myocardial infarction (%) 14 (0.5) 5 (0.6) 0.576 Emergency CABG (%) 82 (2.8) 20 (2.5) 0.776 Repeat PTCA (%) 49 (1.7) 15 (1.9) 0.779 Elective CABG (%) 47 (1.6) 12 (1.5) 0.993

CABG = coronary artery bypass surgery; PTCA = percutaneous translummal comnaryangloplasty.

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1214 THE AMERICAN JOURNAL OF CARDIOLOGY VOLUME 73 JUNE 15, 1994

TABLE II Characteristics of Stable Patients

AMI < 30 Days No Yes p Value

Number of patients 1,121 299 Mean age (years) (SD) 61.8 (10.7) 59.5 (11.3) 0.001 265 years (%) 502 (44.8) 102 (34.1) 0.001 Women (%) 252 (22.5) 71 (23.7) 0.699 Prior CABG (%) 278 (24.8) 25 (8.4) <O.OOl

22 lesions targeted (%I 428 (38.2) 82 (27.4) 10.001 Type C lesion targeted f%) 591 (52.7) 120 (40.1) <O.OOl Device used (%) 463 (41.3) 65 (21.7) <O.OOl

Death (%I 4 (0.4) 4 (1.3) 0.066 Myocardial infarction (%) 3 (0.3) 1 (0.3) 1 .oo Emergency CABG t%) 25 (2.2) 5 (1.7) 0.712 Repeat PTCA (%) 14 (1.2) 5 (1.7) 0.572 Elective CABG (%I 15 (1.3) 3 (1.0) 0.779

Abbrewtfons as in Table I.

the time of the PTCA. When unstable patients were com- pared, the difference was greatest: 2.6% of the 492 with recent AMI died, compared with 0.6% of the 1,813 who had not had such an event (p <O.OOl, odds ratio 4.6, 95% CI 1.9, 11 .I) The difference in stable patients ap- proached but did not reach significance (1.3% vs 0.4%, p = 0.066, odds ratio 3.9, 95% CI 0.8, 20.0).

The frequency of postprocedure AMI, coronary by- pass surgery, or repeat PTCA of the same artery was not increased in patients who had recent AMI.

Because baseline characteristics ofpatients with AMI within 30 days potentially placed them at lower risk for mortality and morbidity compared with the group with no recent AMI, multivariate analysis adjusting for these baseline characteristics was performed. After adjust- ment, the increased risk of death after PTCA in stable patients after AMI compared with stable patients with no recent AMI was significant (p = 0.010, odds ratio 7.3, 95% CI 1.6, 32.9). Moreover, the increased risk of death seen on univariate analysis in unstable patients after AMI versus unstable patients with no recent event persisted after adjustment for baseline variables (p <O.OOI, odds ratio 4.5, 95% CI 2.0, 10.2).

When comparing patients with and without recent AMI, there was an increased risk of dying in the hospi- tal after PICA subsequent to recent AMI, even in sta- ble patients. None of the differences in the analyzed base- line characteristics accounts for this. In fact, a case could be made that younger age, fewer prior coronary artery bypass graft procedures, fewer patients with a target le- sion of type C complexity, less frequent multilesion PTCA, and less frequent use of a device other than a balloon in those with recent AM1 identify them as less likely to have complications.

What factors not identified by this analysis are re- sponsible for the increased risk? Perhaps abrupt reclo- sure of the dilated segment is more common because of persistence of abnormalities of the coronary artery wall or a tendency to thrombosis; however, because nonfatal complications (emergency and elective coronary bypass

TABLE Ill Characteristics of Unstable Patients

AMI < 30 Days No Yes p Value

Number of patients 1,813 492 Mean (years) (SO) age 63.3 (11.4) 62.1 (12.1) 0.040 265 years (%) a78 (48.4) 229 (46.5) 0.490 Women (%I 592 (32.7) 162 (32.9) 0.952 Prior CABG (%) 569 (31.4) 69 (14.0) <O.OOl 2 2 lesions targeted (%) 620 (34.2) 149 (30.3) 0.114 Type C lesion targeted (%) 1,039 (57.3) 280 (56.9) 0.988 Device used (%) 694 (38.3) 102 (20.7) <O.OOl

Death (%) 11 (0.6) 13 (2.6) <O.OOl Myocardial infarction (%) 11 (0.6) 4 (0.8) 0.540 Emergency CABG t%) 57 (3.1) 15 (3.0) 0.969 Repeat PTCA (%I 35 (1.9) 10 (2.0) 0.969 Electrve CABG (%I 32 (1.8) 9 (1.8) 0.923

Abbreviations as m Table I

operations, AMI, and the need for repeat PTCA of the same narrowing) did not occur more often, it appears that the occurrence of a recent AM1 merely provides a marker of a high-risk group of patients that come to PICA with a greater degree of left ventricular dysfunc- tion and more severe obstructive coronary artery disease, and therefore are less able to tolerate an unsuccessful or complicated procedure.

These data support the view that there is an in- creased risk of dying after FTCA when the proce- dure is conducted in the first 30 days after an AMI. Reasons for the greater risk require further investi- gation.

1. TIMI Study Group. Comparison of invasive and conservative strategies after treatment with intravenous tissue plasminogen activator in acute myocardial in- farction. N Engl .I Med 1989;320:618-627. 2. SWIFT Trial Study Group. SWIFT trial of delayed elective intervention v con- servative treatment after thmmbolysis with antistreplase in acute myocardial in- farction. Br Med J 1991;302:555-560. 3. Barbash GI, Roth A, Hod H, Modan M, Miller HI, Rath S, Zahav YH, Keren G, Metro M, Shachar A, Basan S, Agranat 0, Rabinowitz B, Laniado S, Kaplim- sky E. Randomized controlled trial of late in-hospital angiography and angioplasty versus conservative management after treatment with recombiiant tissue-type plas- minogen activator in acute myocardial infarction. Am J Cardiol 1990;66:53&545. 4. Nicod P, Gilpin EA, Dittrich H, Henning H, Maisel A, Blacky AR, Smith SC Jr, Ricou F, Ross J Jr. Trends in use of coronary angiogmphy in subacute phase of myocardial infarction. Circulation 1991;84:10&&1015. 5. Detre K, Holubkov R, Kelsey S, Cowley M, Kent K, Williams D, Myler R, Faxon D, Holmes D Jr, Bourassa M, Block P, Gosselin A, Bentivoglio L, Leather- man L, Dorros G, King S III, Galichia J, Al-Bassam M, Leon M, Robertson T, Pas- samani E. Percutaneous transluminal coronary angioplasty in 1985-1986 and 1977- 198 1. The National Heart, Lung, and Blood Institute Registry. N Engl .I Med 1988; 3 18:265-270. 8. Myler RK, Shaw RE, Stertzer SH, Bashour ‘lT, Ryan C, Hecht HS, Cumber- land DC. Unstable angina and coronary angioplasty. Circulation 1990;82(suppl II):lI-88-11-95. 7. Ellis SC, Mooney MR. George BS, Ribeiio da Silva EE, Talley ID, Flanagan WH, Top01 EJ. Randomized trial of late elective angioplasty versus conservative management for patients with residual stenoses after thrombolytic treatment of myo- cardial infarction. Circulation 199286: 1400-1406. 8. SAS Users Guide. Statistics, version 6. Gary, NC: SAS Institute, 1991. 9. Ryan TJ, Faxon DP. Gunnar RM, Kennedy JW, King SB III, Loop FD, Peter- son KL, Reeves TJ, Williams DO, Winters WL Jr. Guidelines for percutaneous transluminal coronary angioplasty. A report of the American College of Cardiol- ogy/American Heart Association Task Force on the assessment of diagnostic and therapeutic cardiovascular procedures. J Am Coil Cardiol 1988;12:529-545.

BRIEF REPORTS 1215