Percutaneous Transluminal Coronary Angioplasty After Non-Q-Wave Acute Myocardial

Infarction Fernando Alfonso, MD, Carlos Macaya, MD, Andres Ifiiguez, MD, Camino BaAuelos, MD,

Antonio Fernandez-Ortiz, MD, and Pedro Zarco, MD

The value of percutansous transluminal coronary angioptasty (PTCA) for ischemia after a non-Q- wave aa& myocardid infarction (AMI) was as- sessed prospdively in 33 conse&ive patients. In 36patkntsthsindicationfortheprocedurewas post-AM anghw and 3 patients undsrwent PTCA for silent ischemii. A total of 43 lesions were attempted at 63 f 94 days after the non-Q-wave AMI. Rimary PTCA success was obtained in 36 (91%) patknts and no majer compkatii oc- curred. Angiographii evaluation was performed eithsfforsymptomsorforprotocol(7flmonths after PTCA) in 26 (93%) of the 36 patients with succedd PTCA, but 2 patients (7%) who were asymptomatic refused the repeat anglogram. Twenty (71%) had no restenosis and 8 (29%) had restenosis. Of these, 5 patients with restenosis underwenta successfulrepeatPTCA(6fl months after the initial procedure). At ths last clini- cal foilow-up (17 f 8 months), 2 of the 30 (7%) patknts sutxmduliy dilated presented with stable angina despite medii treatment, whereas the rest (93%) remained asymptomatic. During the study period no patient died, had an AMI or required cor- onary artery bypass grafting. Thus, setected patii with ischemia after a non-Q-wave AMI, a ‘Lhigh-risk population,” can be effectively treated with PTCA with an initial success rate and angio- graphic -is rate similar to that of ths gensr- al PTCA population and appear to have sustained symptomatic benefit remaining free of subsequent cardiac events.

(Am J Cardid 199@66S39-639)

From the Cardiopulmonary Department, Hospital Universitario San Carlos, Universidad Complutense, Madrid, Spain. Manuscript received September 20,1989; revised manuscript received and accepted Decem- ber 1,1989.

Address for reprints: Carlos Macaya, MD, Departamento de Car- diopulmonar, Hospital Universitario San Carlos, Plaza de Cristo Rey, Madrid 28040, Spain.

on-Q-wave acute myccardial infarction (AMI) N is generally associated with smaller amounts of myocardial necrosis and a lower early mortality

rate than Q-wave AMI. L* Despite this favorable initial outcome, long-term prognosis is hampered with a higher incidence of post-AM1 angina and recurrent AMI, yielding a long-term survival similar to or even less than that of patients with Q-wave AMI.3-6 Different ap- proaches, including medical treatment with diltiazem and coronary artery bypass surgery, have been suggest- ed to improve the prognosis of these patients.7-9 The usefulness of percutaneous transluminal coronary angio- plasty (PTCA) in patients with angina after a non-Q- wave AM1 has been reportedlOJ’ However, no system- atic information exists concerning the angiographic fol- low-up of patients with successful PTCA in this setting. Accordingly, the present investigation was designed to prospectively evaluate the early outcome and especially the clinical and angiographic follow-up of patients dilat- ed for ischemia after a non-Q-wave AMI.

MERtOD6 Patienti The study population consisted of 33 con-

secutive patients with non-Q-wave AM1 who underwent PTCA (including 43 lesions) for post-AM1 angina (30 patients) or silent ischemia (3 patients) between Febru- ary 1985 and February 1989. They represented 6.1% of our total PTCA population during the study period. Mean age was 59 f 9 years and 30 patients (91%) were men. Thirty (91%) patients were receiving calcium an- tagonists (diltiazem in 13). Non-Q-wave AM1 was de- fined as chest pain characteristic of myocardial isch- emia with documented ST- or T-wave changes but without progression to pathologic Q waves and with a creatinine kinase elevation of at least twice the upper limit of the normal value. Four patients with PTCA performed > 1 year after the non-Q-wave AM1 were not included in the study group. PTCA was undertaken 63 f 94 days (range 3 to 330) after the non-Q-wave AMI. The peak increase in creatine kinase in the non-Q-wave AM1 was 607 f 310 III/liter. Selection for PTCA was considered based on symptoms, electrocardiographic documentation of ischemia, results of exercise testing and suitability for dilatation of the ischemia-related ar- tery. PTCA was performed within 1 month of the non- Q-wave AM1 in 20 (61%) patients, from 1 to 2 months in 6 (18%) from 2 to 6 months in 3 (9%) and from 6 months to 1 year in 4 (12%). To assess if the restenosis rate was related to the elapsed time from the non-Q-

THE AMERICAN JOURNAL OF CARDIOLOGY APRIL 1. 1990 835

wave AM1 to the PTCA, we considered 2 groups (time I1 month and >l month).

P8fcutaneous tranduminal coronary angioplasty protocol and detfinitions: Clinical and angiographic variables were prospectively introduced into a database on completion of PTCA for subsequent analysis. We followed the National Heart, Lung, and Blood Institute angioplasty criteria for the diagnosis of unstable angi- na.12 Multiple views of the right and left coronary sys- tems were obtained including angulated cranial-caudal views, to accurately delineate coronary anatomy. To en- sure the uniformity of interpretation, all angiograms were independently analyzed by 2 investigators unaware of the patient’s clinical status. The guiding catheter was used as a reference for the arterial vessel measurements. We only attempted to dilate lesions with stenosis 175% of huninal diameter. The anterograde flow of the in- farct-related artery was quantitated by the Thromboly- sis in Myocardial Infarction trial (TIMI) criteria as grade 0 to 3.13 Primary angiographic success was de- fined as an increase in luminal diameter of at least 40% providing that the residual stenosis was <XV&l4 Pri- mary angioplasty success was defined as the procedure that in the absence of any major complication (includ- ing death, AM1 or emergency coronary artery bypass grafting) successfully dilated at least the culprit lesion.15 Restenosis was defined when at least one of the lesions previously dilated successfully had a recurrence in lumi- nal narrowing >50% at follow-up.16

We performed PTCA using steerable catheters and always attempted a balloon:artery ratio of 1:l. Right anterior oblique (30°) left ventricular angiograms were obtained and computer-assisted ejection fraction was calculated by the area-length method.” All patients re- ceived platelet inhibitors before the procedure and a bo- lus of 10,000 U of heparin was given at the beginning of PTCA. Patients were transferred to the coronary care unit where a close electrocardiographic and enzymatic surveillance was performed. Intravenous heparin was continued for 24 hours at an adjusted rate to maintain activated partial thromboplastin time at 1.5 to 2 times control.

Clinical and angiographic follow-up: Patients were seen in the outpatient clinic within 2 weeks, at 3 to 4 and 6 to 9 months and every year thereafter. Both clini- cal status and adherence to medication were assessed. Calcium antagonists and platelet inhibitors were pre- scribed for at least 6 months. Every visit also included an exercise test with a modified Bruce protocol.‘* Whenever symptoms recurred or the exercise test be- came positive, patients were advised to have a repeat coronary angiogram. In addition, our protocol was spe- cifically designed to assess the angiographic follow-up in these patients, and included a repeat coronary angio- gram at 6 to 9 months even for asymptomatic patients. Patients were informed that the results of the angio- graphic follow-up might be of direct help in the deci- sion-making process involved in their management, and oral informed consent was obtained in every case. We prospectively entered the follow-up data in our database when they were obtained.

Statistical analysis: Continuous variables were ex- pressed as mean f 1 standard deviation. We used the chi-square test to compare noncontinuous data. A p val- ue <0.05 was considered statistically significant.

RESULTS Clinical and angiographic profile: Of the 33 pa-

tients, 30 had PTCA for angina that was classified as stable in only 2 patients and unstable in the rest. In 3 patients PTCA was performed for silent ischemia. In addition 9 patients also had a positive exercise test per- formed just before the PTCA (3 patients with diagnos- tic ST changes and 6 with both angina and ST changes). The ejection fraction was 64 f 11%. Lesion characteristics are summarized in Figure 1. Mean lesion length was 5 f 2 mm. The mean number of diseased vessels was 1.33 f 0.6 (l-vessel disease was found in 25 [76%] patients), and the number of lesions attempted/ procedure was 1.30 f 0.7. Complete revascularization was achieved in 29 (88%) patients. Five lesions were considered total occlusions (1 lesion TIM1 0 and 4 le sions TIM1 l), 5 lesions were TIM1 2 and the remain- ing 33 lesions were TIM1 3. Before the procedure the

(%)

ECC IRR BIF BEND THR occ COL CA*

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836 THE AMERICAN JOURNAL OF CARDIOLOGY VOLUME 65

stenosis was 86 f 9% and the residual stenosis after dilatation was 24 f 22%.

Percutaneous transluminal coronary angioplasty immediate results: Primary angiographic success was achieved in 39 of 43 (91%) attempted lesions, and PTCA success was obtained in 30 of 33 (91%) proce- dures. In the 3 failed procedures the attempted lesions had a total occlusion (1 case TIM1 0 and 2 cases TIM1 1). The 2 patients with total occlusions (TIM1 grade 1) who had successful PTCA underwent an early angio- graphic control at 24 hours and both showed persistence of the angiographic success. No major complications oc- curred in any patient. There were no side-branch occlu- sions. Two patients developed prolonged chest pain and in 1 patient coronary spasm was documented during the PTCA, all these being minor reversible complications controlled with intracoronary nitroglycerin. No patient presented signs or symptoms of reocclusion before dis- charge.

Clinical and angiographic follow-up: The 30 patients with successful PTCA were included in our angiograph- ic follow-up protocol. Two patients (7%) declined the invasive investigation while asymptomatic and with a negative exercise test. In the remaining 28 patients (93%) the repeat angiogram was performed according to the protocol, 7 f 1 months after PTCA. Figure 2 summarizes the angiographic results of the 30 patients with successful PTCA. Of the 8 patients with restenosis, 3 presented a total occlusion (TIM1 grade 0 in 2 and TIM1 grade 1 in 1) and repeat PTCA was not attempt- ed, as they were successfully controlled with medical treatment, whereas the remaining 5 patients with reste- nosis successfully underwent a second PTCA 6 f 1 months after the initial procedure. In 3 of these patients the repeat PTCA was performed for unstable angina,

FIGURE 2. Angiograplic fobw-q. ANGtG = an& ographkconbol;PTCA=

!ltzzgYs- R=re&nosisotatt lkrlon;Tx=trerrbnent.

whereas in 2 the procedure was indicated only for posi- tive ST criteria during the exercise test. Of the 5 repeat PTCAs, 2 patients had an asymptomatic recurrence of restenosis and were treated medically, 2 patients had no recurrence of restenosis and 1 patient, being asymptom- atic, had insufficient time for the repeat angiogram. Of the 20 patients without restenosis, 2 had occasional sta- ble angina despite an increase in medical treatment and the rest were asymptomatic. One of them had a residual stenosis of 40% in the left anterior descending coronary artery and a nondilated stenosis that progressed to 75% in the distal left circumflex artery, whereas the other patient had a residual stenosis of 20% in the right coro- nary artery and a nondilated lesion of 50% in a diagonal branch. The presence of restenosis at follow-up was higher in those patients requiring an early PTCA (5 1 month) after the non-Q-wave AMI: 5 of 14 (36%) ver- sus 3 of 14 (21%) (difference not significant).

At the last visit (17 f 8 months), the results of the exercise test in the 30 patients with successful PTCA were as follows: in 23 (77%) negative, in 1 (3%) positive for angina, in 4 (13%) positive only for ST criteria and nonconclusive for 2. At this last clinical evaluation and considering the repeat PTCA for restenosis as an inte- gral part of the PTCA strategy, 2 of the 30 (7%) pa- tients with successful PTCA complained of stable angi- na while receiving medical treatment, whereas the re- maining 28 patients (93%) were free of symptoms. In addition, during this time no patient died, had a re- infarction or required surgery.

DISCUSSION Our data confirm that PTCA is an effective means

for treating patients with ischemia after a non-Q-wave AMI. PTCA in this clinical setting provides not only a

(9%) FilL”RE

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THE AMERICAN JOURNAL OF CARDIOLOGY APRIL 1, 1990 837

high primary success rate, but also continued symptom- atic relief and a favorable outcome for at least 1.5 years. In addition, this is the first study in which the restenosis rate of PTCA after a non-Q-wave AM1 has been pro- spectively and systematically assessed. With a high an- giographic follow-up avaiable (93%) our results also demonstrate that the restenosis rate in these patients (29%) is similar to that found in the general FTCA pop ulation.

Non-Q-wave myocardial infarction charactericllcs: The electrocardiographic classification of Q-wave and non-Q-wave AM1 presents some limitations,19v20 but it provides prognostic information and has gained wide- spread clinical use. 1-8 Anatomic and hemodynamic studies have provided a comprehensive explanation for the higher rate of untoward cardiac events that follow a non-Q-wave AMI. Histologic observations after fatal non-Q-wave AM12* suggested transient hypoperfusion or reperfusion. Subsequently, DeWood et a122 empha- sized that only 37% of patients with non-Q-wave AM1 had a total occlusion of the infarct-related vessel, and that both occlusion rate and presence of collaterals steadily increased with time.

After a non-Q-wave AMI, most efforts have concen- trated on the identification of clinical markers able to predict patients at higher risk for subsequent cardiac events in whom a more aggressive approach seems war- ranted. The presence of post-AM1 angina, especially if associated with ST-T changes23 and the presence of a positive exercise teat before discharge24 have been pre posed as useful clinical tools in the identification of pa- tients with poorer prognosis. Therefore, various thera- pies including medical treatment with diltiazem,7 coro- nary artery bypass surgery*+9 and PTCA’OJ 1 have been advocated for treating these “high-risk patients.”

Angiepbty after non-Q-wave myocardial infarc- tion: Recently, PTCA has been used in the treatment of patients with angina after a non-Q-wave AMI. Safian et allo obtained a PTCA success rate of 87%, but recur- rent angina developed in 41% of patients and they sug- gested that PTCA in this setting presented a high “clin- ical restenosis rate.” In addition they found that a shorter period of time between AM1 and PTCA in- creased the angina recurrence rate. The need for repeat PTCA in this study was 25% and for coronary artery bypass grafting 4%. Subsequently, Suryapranata et al” reported a larger series with a PTCA success rate of 86%. However, emergency bypass surgery was required in 6% of patients after FTCA, an additional 6% devel- oped an AM1 during follow-up and 32% were affected by recurrent angina (16% requiring repeat PTCA and 4% surgery), which in this study was also more frequent among patients treated early after the non-Q-wave AMI. Nevertheless, no systematic angiographic evalua- tion was obtained in these 2 studies, and in particular, no information was given with regard to whether the revascularization procedures used at follow-up were used in the treatment of restenosis or in the treatment of other preexisting but not previously dilated lesions. This latter point is relevant because >33% of the patients in both series presented with multivessel disease.

838 THE AMERICAN JOURNAL OF CARDIOLOGY VOLUME 65

Our study demonstrated a restenosis rate, per pa- tient, of 29%, most of them successfully treated with repeat PTCA. When this second procedure was consid- ered as an integral part of our PTCA strategy, most patients (93%) remained asymptomatic, Although the rate of patients with restenosis was also higher in this study in the group dilated early after the non-Q-wave AMI, the difference was not statistically significant, probably reflecting our smaller population. In addition, coronary artery bypass grafting was not required during follow-up in any patient, and no deaths or reinfarctions occurred. We only failed to dilate the infarct-related le sion in 3 patients, all with a total functional occlusion. This is in accordance with the results of Suryapranata et al,” who reported only a 59% primary success rate when recanalization was attempted in a totally occluded artery in patients with non-Q-wave AMI.

Although it would be tempting to speculate that our results compare favorably with previous series of pa- tients with ischemia after a non-Q-wave AMI, great caution is required because the uncontrolled nature of the present study prevents ruling out some selection bias. This series has some characteristics that differ from previous PTCA studies including a lower rate of total occlusions, and a higher percentage of patients with l-vessel disease. Moreover, because most patients (76%) in our series have l-vessel disease, the compari- son with previous surgical series where only 36% of pa- tients had l-vessel disease and 68% received 12 grafts8 is not adequate.

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