Author + information
- Received November 19, 1996
- Revision received July 15, 1997
- Accepted August 5, 1997
- Published online November 15, 1997.
- David Tanne, MDA,2,2,
- Shmuel Gottlieb, MDA,
- Hanoch Hod, MD, FACCA,
- Henrietta Reicher-Reiss, MD, FACCA,
- Valentina Boyko, MScA,
- Solomon Behar, MDA,
- for the Secondary Prevention Reinfarction Israeli Nifedipine Trial (SPRINT),
- Israeli Thrombolytic Survey Groups1
Objectives. This study sought to compare the incidence of early cerebrovascular events and subsequent mortality in two cohorts of consecutive patients with acute myocardial infarction (AMI), admitted to coronary care units (CCUs) in Israel, in the prethrombolytic and thrombolytic eras.
Background. During the past decade, substantial changes have occurred in the medical treatment of AMI, and important new therapies have been introduced that could all affect stroke risk and type by diverse mechanisms. Yet the overall impact of these new therapeutic modalities on the incidence of stroke complicating AMI is not clear.
Methods. We compared the incidence and mortality rates of cerebrovascular events complicating AMI within CCUs among 5,839 consecutive patients admitted in the period 1981 to 1983 versus 2,012 patients from two prospective nationwide surveys conducted in all CCUs operating in Israel in 1992 and 1994.
Results. The demographic and clinical characteristics of patients with AMI in both periods were comparable. Patients admitted in the period 1981 to 1983 did not receive thrombolysis and reperfusion therapy; those admitted in 1992 and 1994 received thrombolysis (45%) and coronary angioplasty or coronary artery bypass graft surgery (14%), and antiplatelet and anticoagulant treatments were more frequently used. The incidence of early cerebrovascular events was 0.74% (43 of 5,839) in 1981 to 1983 versus 0.75% (15 of 2,012) in the 1992 to 1994 cohort. Patients with an AMI who experienced a cerebrovascular event were somewhat older in both groups and had a high rate of previous cerebrovascular events, congestive heart failure and atrial and ventricular arrhythmias during the hospital period. Mortality declined by one-third between the two periods. However, the mortality rate of patients with AMI who sustained a cerebrovascular event remained high (≥40% for 30 days, 60% for 1 year).
Conclusions. The overall incidence of early cerebrovascular events complicating AMI remained similar (0.75%) in the prethrombolytic and thrombolytic eras. Mortality rates of patients with an AMI but no cerebrovascular events decreased substantially over the past decade but not in patients with AMI with a cerebrovascular event.
Stroke is a well known, potentially catastrophic complication of acute myocardial infarction (AMI). Before the advent of thrombolysis, the reported incidence of stroke in the acute phase of the infarction varied between 0.8% and 5.5% [1–4]. Most strokes were considered to be cardioembolic, as indicated by their association with large anterior myocardial infarctions and left ventricular thrombi detected by echocardiography.
Over the past decade, the management of AMI has changed dramatically and includes improved medical treatment, thrombolytic therapy and mechanical revascularization. These therapeutic modalities may affect the rate and type of stroke by diverse mechanisms. However, the overall impact of these changes in therapy on the incidence of stroke complicating AMI in an unselected postinfarction population is not clear.
Valuable information on overall stroke incidence, type and functional outcome after thrombolytic therapy for AMI was provided by the large comparative trials of thrombolytic agents, and, in particular, the Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-1) megatrial [5–8]. These and other recent trials have suggested that effective use of thrombolytic therapy has been accompanied by more intracranial hemorrhages and slightly less ischemic strokes [9–11]. Yet data in the thrombolytic era are mostly derived from clinical trials in which selected patients receive thrombolysis under strict protocols that exclude high risk patients. Moreover, wide methodologic variations complicate any comparison with studies conducted in the prethrombolytic era.
The aim of the present study was to compare the incidence and mortality from early cerebrovascular events in two large cohorts of consecutive patients with an AMI admitted to coronary care units (CCUs) in Israel, one during 1981 to 1983 (prethrombolytic era), and the other during 1992 and 1994 (thrombolytic era).
This report analyzed data from two cohorts of consecutive patients admitted to CCUs in Israel with a diagnosis of AMI. The first cohort (Secondary Prevention Reinfarction Israeli Nifedipine Trial [SPRINT] registry ) included 5,839 consecutive patients with an AMI admitted to 13 CCUs in Israel between August 1981 and July 1983. Thrombolysis was not provided to any patient in this cohort. The second cohort was derived from two prospective national surveys conducted during 2-month periods (January and February) in 1992 and 1994, respectively, and included 2,012 consecutive patients with a confirmed AMI admitted to all 25 operating CCUs in Israel. During the survey of 1992 (n = 1,012), all CCUs followed uniform guidelines for thrombolytic treatment because all participated in the international GUSTO-1 trial . Patients ineligible for the GUSTO-1 trial who did not receive thrombolytic therapy or who nevertheless received thrombolytic therapy at the discretion of the treating physician and patients who underwent mechanical reperfusion (percutaneous transluminal coronary angioplasty [PTCA] or coronary artery bypass graft surgery [CABG]) were all included in the survey. In 1994 (n = 1,000), thrombolytic therapy and invasive procedures were utilized at the discretion of each center. Both cohorts in the 1980s and 1990s included all consecutive patients with an AMI admitted to the CCUs during the respective designated time periods, and both cohorts included patients on hospital admission.
Demographic and clinical data were recorded for all registered patients with an AMI in both cohorts by study physicians in the CCUs. Historical characteristics were based on self-report by patients at the time of hospital admission. Identical criteria were used in both cohorts for diagnosis of AMI and stroke. Diagnosis of AMI was based on the presence of any two of the following: typical chest pain lasting at least 30 min, unequivocal new electrocardiographic changes (Q/QS or ST segment and T wave changes, or both); or an increase of at least two of the serum cardiac enzymes (creatine kinase, glutamic oxaloacetic transaminase and lactate dehydrogenase) to >1.5 times the upper limit or a concomitant increase in creatine kinase-MB isoenzyme. The diagnosis of a cerebrovascular event was based on rapidly developing clinical signs of focal neurologic deficit. Ischemic strokes and intracerebral hemorrhages were differentiated by brain imaging, when available, in the 1992 to 1994 period. No attempt was made to differentiate stroke types in the 1981 to 1983 period because brain imaging was less available and seldom performed during that period.
Data were analyzed at the same coordinating center, and individual records of all reported cerebrovascular cases from both cohorts were reviewed by the same investigator (D.T.). Rates of cerebrovascular events from day of admission and within CCUs (early cerebrovascular events) were compared between the two cohorts. Mortality follow-up of at least 1 year duration after hospital discharge was conducted in both cohorts, with information available for 5,781 patients (99%) in the 1981 to 1983 period and for 1,940 patients (96%) in the 1992 to 1994 cohort.
1.1 Statistical Analysis
All analyses were performed using SAS statistical software . Chi-square and ttests were used to determine the significance of the differences between proportions and mean values, respectively, where appropriate. Results of continuous variables are reported as mean value ± SD. Two-sided p values are reported.
The pooled Mantel-Haenszel relative risk was used to compare mortality in the 1992 to 1994 versus 1981 to 1983 periods (where mortality in the 1981 to 1983 period was the reference group) controlling for age, gender, diabetes mellitus, hypertension, anginal syndrome, previous myocardial infarction, congestive heart failure on admission and anterior site of myocardial infarction. Survival curves were estimated using the Kaplan-Meier method.
The baseline characteristics and in-hospital complications and procedures for the two periods for all AMI patients and for patients sustaining an early cerebrovascular event are presented in Table 1.
2.1 Patient Characteristics
The demographic and clinical characteristics of the two cohorts of patients with AMI in the two periods were comparable. The mean age and proportion of men were similar. In the 1992 to 1994 period, the prevalence of current smoking, diabetes mellitus, previous cerebrovascular event and MI were somewhat higher, and the prevalence of anginal syndrome was lower. The proportion of patients with hypertension and an anterior location of the index AMI was similar during both periods. Patients in the 1992 to 1994 period had less congestive heart failure on admission and fewer in-hospital complications, including ventricular tachycardia or fibrillation, paroxysmal atrial fibrillation and congestive heart failure. Patients sustaining a cerebrovascular event after AMI were somewhat older in both cohorts and had a higher rate of a previous cerebrovascular event, congestive heart failure and atrial and ventricular arrhythmias during the hospital period (Table 1).
Major changes in patient management occurred between the two periods. Whereas in the 1981 to 1983 period, thrombolytic therapy was not provided, and coronary angiography, PTCA and CABG were almost not performed, in the 1992 to 1994 period, thrombolysis was provided in 909 patients (45%), coronary angiography in 515 (26%) and PTCA or CABG in 282 (14%) during the index hospital period (Table 1). During the 1992 to 1994 period, aspirin therapy was provided in 1,570 patients (78%), anticoagulation in 923 (46%) and beta-adrenergic blocking agents in 752 (37%). Data for in-hospital medications during the 1981 to 1983 period are lacking. Among patients discharged alive during the 1981 to 1983 period, aspirin was provided in 147 (3%), dipyridamole in 683 (14%), anticoagulant agents in 85 (2%) and beta-blockers in 852 (18%).
The overall incidence of cerebrovascular events complicating AMI in the two cohorts are presented in Table 2. Incidence of early cerebrovascular events (within CCUs) was similar in both periods: 0.74% (43 of 5,839 patients) for the 1981 to 1983 period versus 0.75% (15 of 2,012 patients) for the 1992 to 1994 period. The incidence of cerebrovascular events during the entire hospital period, available for the 1981 to 1983 but not the 1992 to 1994 cohort, was 0.92% (54 of 5,839 patients). Brain imaging results were available for 8 of 15 patients with stroke in the 1992 to 1994 period. In all eight patients, brain imaging results were compatible with an ischemic stroke, with secondary hemorrhagic transformation in two. In the other seven patients without brain imaging or autopsy, strokes were regarded to be of undetermined origin, and the number of parenchymatous intracerebral hemorrhages among them is not known. Intravenous heparin before the cerebrovascular event was provided in 1 of the 43 patients who sustained a cerebrovascular event during the 1981 to 1983 period and in 6 of the 15 patients in the 1992 to 1994 period. None of the cerebrovascular events were suspected by the treating physician to be secondary or due to excessive anticoagulation. In the 1992 to 1994 period, stroke occurred in nine patients (1%) treated with thrombolysis (eight with streptokinase, one with streptokinase and tissue-type plasminogen activator) versus six (0.5%) patients with no thrombolysis. Left ventricular thrombi were demonstrated by transthoracic echocardiography in one-third (5 of 15) of patients with stroke, and an additional stroke was associated with coronary angiography.
Table 3demonstrates the cumulative mortality in 1981 to 1983 versus the 1992 to 1994 period for all patients with AMI and for patients with an early cerebrovascular event. Mortality rates for all patients with AMI declined substantially from the 1981 to 1983 period to the 1992 to 1994 period. The 7-day, 30-day and 1-year mortality rates decreased from 13%, 19% and 27% during 1981 to 1983 to 8%, 13% and 19%, respectively, during 1992 to 1994. After multivariate analysis adjusting for age and possible confounding variables (see Methods), the covariate adjusted risk reduction in the 1992 to 1994 versus the 1981 to 1983 period was of the magnitude of 30% for 7-day, 30-day and 1-year cumulative mortality rates.
Mortality rates of patients sustaining an early cerebrovascular event during AMI were high during both periods, with 30-day and 1-year mortality rates of ≥40% and 60%, respectively (Table 3). Kaplan-Meier survival curves for patients with early cerebrovascular events during the two periods are depicted in Fig. 1.
The main finding of this reportis that the overall incidence of early cerebrovascular events complicating AMI did not change in our two consecutive cohorts of patients with AMI admitted to CCUs in the early 1980s and early 1990s. During that period, major changes in management took place, and subsequently, the outcome after AMI improved substantially. However, mortality rates of patients sustaining a cerebrovascular event remained high during both periods.
3.1 Incidence of Stroke in the Prethrombolytic Era
The reported incidence of stroke complicating AMI in the prethrombolytic era varied mostly between 0.8% and 5.5% [1–4]. Although brain imaging was not available, the occurrence of intracranial hemorrhage seemed exceedingly rare, and most strokes were attributed to cerebral embolism. An apparent reduction in the incidence of stroke complicating AMI in recent decades was noted in a meta-analysis , but heterogeneity among the trials complicated the interpretation of this trend.
3.2 Changes in Management of AMI
The management of AMI changed substantially between the early 1980s and early 1990s, as shown in the present study. New therapies were introduced for AMI, specifically thrombolysis and other reperfusion therapies (immediate PTCA and CABG). Other medical therapies, such as aspirin, beta-blockers, angiotensin-converting enzyme inhibitors and heparin, gained widespread use. In the 1992 to 1994 period, thrombolytic therapy was provided in nearly 50% of patients; other reperfusion strategies were often utilized; and antiplatelet and anticoagulant treatments were provided in high rates. Indeed, these changes were associated with a substantial reduction in cumulative mortality rates of patients with AMI compared with those during the 1981 to 1983 period.
These changes in the management of AMI may affect stroke rates and types by diverse mechanisms. Aspirin reduced the risk of early ischemic stroke by half in the Second International Study of Infarct Survival (ISIS-2) trial . Anticoagulation may decrease the risk of left ventricular thrombi in patients with anterior site AMI and may be effective in reducing the risk of embolic strokes in those with left ventricular thrombi [15, 16]but is associated with an increased rate of intracranial hemorrhage. The higher than anticipated rate of intracranial hemorrhage among patients treated with heparin versus hirudin in conjunction with thrombolysis in the GUSTO-IIa , TIMI-9A , and HIT-III trials emphasizes the risks of more potent anticoagulation in combination with thrombolysis and the narrow therapeutic/toxic ratio.
The main fear from thrombolytic therapy after AMI is the development of a major hemorrhagic complication, especially an intracranial hemorrhage. After thrombolysis, a shift in type of strokes was demonstrated: more intracranial hemorrhages albeit somewhat less ischemic strokes [9–11]. Thrombolytic therapy was shown [15, 16]to reduce the incidence of protruding and mobile left ventricular thrombi and subsequent embolic strokes. However, thrombolysis may occasionally dislodge parts from an already existing left ventricular thrombus and cause an embolic stroke . Ischemic stroke may occur during other reperfusion therapies (PTCA and CABG), mainly as a result of embolism or hemodynamic compromise.
3.3 Incidence of Stroke Since the Advent of Thrombolysis
In controlled thrombolytic trials [5–9], the reported incidence of stroke was 0.9% to 1.6%, of which intracranial hemorrhage represented 0.2% to 0.9%, depending on the type and dose of agent used. In a collaborative overview of large, randomized thrombolytic trials , an extra 4 strokes/1,000 patients were associated with thrombolysis versus placebo. An excess risk of intracranial hemorrhage was observed with tissue-type plasminogen activator compared with streptokinase [5–7]. Since the advent of thrombolysis, only a minority of patients with AMI, those who are mainly low risk patients, have received thrombolytic therapy [21, 22]. In a community-based study , the overall stroke rate during the hospital period was 1.6% among patients with AMI treated with thrombolysis versus 2.2% among the 75% of patients excluded from thrombolytic therapy for a variety of reasons.
3.4 Comparison of Stroke Incidence Between Periods
The recent megatrials provide extensive data on stroke incidence, type and outcome after thrombolysis among patients with AMI. However, these trials include only patients treated with thrombolysis. Yet, the majority of patients with AMI in the community are not treated with thrombolysis . A main advantage of the present report is the opportunity to evaluate overall stroke incidence in two unselected cohorts of patients with AMI, separated by a decade, in which management changed substantially. Both of our cohorts, although small compared with the large thrombolysis cohorts, include consecutive patients with AMI admitted to most (during 1981 to 1983) and all (during 1992 to 1994) CCUs operating in Israel. One of the important findings of the present study is that the overall incidence of early cerebrovascular events was similar and did not increase during the 1992 to 1994 period, although thrombolysis was provided to almost 50% of patients with AMI versus one decade earlier.
3.5 Prognosis After Stroke
Stroke complicating AMI adversely affects outcome. In the prethrombolytic era, an estimated threefold increase in in-hospital and long-term mortality rates was observed among patients with versus those without a cerebrovascular event [2–4]. Intracerebral hemorrhage induced by thrombolytic therapy is associated with a higher mortality rate. In the GUSTO-1 megatrial , 17% of patients with a nonhemorrhagic stroke died versus 60% with an intracerebral hemorrhage. In our two cohorts of patients, the mortality rates of patients sustaining any cerebrovascular event were increased about threefold. The comparable mortality rates may reflect the continued dominance of ischemic stroke over intracerebral hemorrhage in the 1990s. Contrary to the dramatic change in the management of AMI during the past decade, little change occurred in the management of ischemic stroke or intracerebral hemorrhage. Accordingly, although the survival of patients with AMI improved substantially, the prognosis of those sustaining a stroke remained poor. Recent advances and an increasingly active approach in the management of both acute ischemic stroke and intracerebral hemorrhage may potentially lead to a better prognosis for these patients [24, 25].
3.6 Study Limitations
We compared the rates of cerebrovascular events complicating AMI within the CCU only. However, most cases of stroke, as demonstrated in our 1981 to 1983 cohort, occur early during the hospital period in the CCU, and any increase in intracranial hemorrhage from thrombolysis would be expected in this time period . Rates may possibly be somewhat underestimated in our cohorts because of an incomplete recognition of minor cerebrovascular events. However, comparison is facilitated by the fairly similar demographic and clinical characteristics, diagnostic criteria and methods in both cohorts. Because of the small number of patients with a cerebrovascular event in the 1992 to 1994 period and their incomplete evaluation, we were not able to report on the rate of ischemic versus hemorrhagic strokes. However, left ventricular thrombi on transthoracic echocardiography were evident in one-third of patients with stroke in this cohort, and the type of stroke was ischemic in those patients examined by brain imaging, suggesting a high rate of cardioembolic ischemic strokes in the unselected 1992 to 1994 cohort.
3.7 Clinical Implications
During the past decade, thrombolytic therapy and new therapeutic modalities reduced mortality and morbidity after AMI. With these therapies, concerns were raised that the incidence of stroke in clinical practice will increase as a result of more intracranial hemorrhages. Nevertheless, our results show that the improvement in outcome after AMI in the 1990s compared with the 1980s was not accompanied by a higher rate of early cerebrovascular events and that embolic cerebral infarction remains the common stroke type. Further studies are needed to find new variables that may identify patients prone to develop hemorrhagic strokes from thrombolysis and to assess the benefit of immediate PTCA in such high risk patients.
We are indebted to all the physicians and nurses who participated in the Israeli National Thrombolytic Survey. We are grateful to Dalia Ben-David for coordinating the data collection, Mark Goldberg for programming the data base, Miriam Cohen for data analysis, Lori Mandelzweig for editorial assistance and Lynn Goodman for typing the manuscript.
A.1 Participating Centers, Directors of Cardiac Departments and Responsible Physicians for the Israeli National Thrombolytic Survey
Assaf Harofeh Hospital, Zerifin: Zwi Schlesinger, MD, Hady Faibel, MD; Barzilai Medical Center, Ashkelon: Leonardo Reisin, MD, Jamal Jafari, MD; Beilinson Medical Center, Petach Tikvah: Samuel Sclarovsky, MD, Boris Strasberg, MD, Eldad Rehavia, MD; Bikur Cholim Hospital, Jerusalem: Shlomo Stern, MD, Andre Keren, MD, Shmuel Gottlieb, MD; Bnei-Zion Medical Center, Haifa: Edward Abinader, MD, Ehud Goldhammer, MD; Carmel Hospital, Haifa: Basil S. Lewis, MD, Nabil Mahul, MD, David Hallon, MD, Moshe Flugelman, MD; Carmel Hospital and “Lin” Medical Clinic, Haifa: Abraham Palant, MD, Chen Shapira, MD; Central Emek Hospital, Afula: Tiberiu Rosenfeld, MD, Nahum A. Friedberg, MD; Hadassah, Ein-Kerem, Medical Center, Jerusalem: Mervyn S. Gotsman, MD, Yonatan Hasin, MD, Chaim Lotan, MD; Hadassah, Mount Scopus, Jerusalem: Teddy A. Weiss, MD, Shimon Rosenheck, MD; Hasharon Hospital, Petach Tikvah: Izhar Zahavi, MD, Menachem Kanetti, MD; Hillel Yaffe Hospital, Hadera: Benyamin Pelled, MD, Fatchy Daka, MD, Magdalah Rashmi, MD; Ichilov Hospital, Sourasky Medical Center, Tel Aviv: Shlomo Laniado, MD, Arie Roth, MD; Josephtal Medical Center, Eilat: Alen Gelvan, MD; Kaplan Hospital, Rehovot: Avraham Caspi, MD, Oskae H. Kracoff, MD, Michael Oettinger, MD; Meir Hospital, Sapir Medical Center, Kfar Saba: Daniel David, MD, Hana Pauzner, MD; Rambam Medical Center, Haifa: Walter Markiewicz, MD, Haim Hammerman, MD, Boaz Benari, MD; Rebecca Sieff Medical Center, Safed: Alon T. Marmor, MD, David Blondheim, MD; Shaare Zedek Medical Center, Jerusalem: Dan Tzivoni, MD, Jonathan Balkin, MD, Mark Klutstein, MD; Sheba Medical Center, Tel Hashomer: Elieser Kaplinsky, MD, Hanoch Hod, MD; Soroka Medical Center, Beersheva: Natalio Kristal, MD, Alexander Battler, MD, Amos Katz, MD, Arie Gilutz, MD; Western Galilee Hospital, Naharia: Nathan Roguin, MD; Wolfson Medical Center, Holon: Yehezkiel Kishon, MD, Ron Narinsky, MD (deceased), Michael Kriwiski, MD. Coordinating Center of the National Israeli Thrombolytic Survey: S. Behar, MD, Neufeld Cardiac Research Institute, Sheba Medical Center, Tel Hashomer.
A.2 SPRINT Study Group
Executive Board. Henry N. Neufeld, MD, Chairman(deceased); Jacob Agmon, MD, Vice-Chairman; Solomon Behar, MD, Uri Goldbourt, PhD, Henrietta Reicher-Reiss, MD, Edward Abinader, MD, Jacob Barzilay, MD, Natalio Cristal, MD, Yaacov Friedman, MD, Nissim Kauli, MD, Yehezkiel Kishon, MD, Abraham Palant, MD, Benyamin Peled, MD, Leonardo Reisin, MD, Egon Riss, MD (deceased), Zwi Schlesinger, MD, Izhar Zahavi, MD, Monty Zion, MD.
Participating Centers, Principal Investigators and Physicians. Assaf Harofeh Hospital, Zerifin: Principal Investigator, Zwi Schlesinger, MD, Physician, Moshe Algom, MD; Barzilai Medical Center, Ashkelon: Principal Investigator, Leonardo Reisin, MD, Physician, Newton Yalom, MD; Beilinson Medical Center, Petach Tikvah: Principal Investigator, Yaacov Friedman, MD; Carmel Hospital and Medical Clinic “Lin” Haifa: Principal Investigator, Abraham Palant, MD, Physician, Ephraim Mayer, MD; Central Emek Hospital, Afula: Principal Investigator, Jacob Barzilay, MD, Physician, Lev Bloch, MD; Hasharon Hospital, Petach Tikvah: Principal Investigator, Izhar Zahavi, MD, Physician, Menachem Katz, MD; Hillel Yaffe Hospital, Hadera: Principal Investigator, Benyamin Pelled, MD, Physician, Zakki Abu-Moukh, MD; Kaplan Hospital, Rehovot: Principal Investigator, Nissim Kauli, MD, Physician, Emanuel Liebman, MD; Rambam Medical Center, Haifa: Principal Investigator, Egon Riss, MD (deceased), Physician, Jamil Hir, MD; Bnei Zion Center, Haifa: Principal Investigator, Edward Abinader, MD, Acting Principal Investigator, Ehud Goldhammer, MD, Physician, Salim Maalouf, MD; Shaare Zedek Medical Center, Jerusalem: Principal Investigator, Monty Zion, MD, Physicians, David Rosenmann, MD, Jonathan Balkin, MD; Sheba Medical Center, Tel Hashomer: Principal Investigator, Henrietta Reicher-Reiss, MD; Wolfson Medical Center, Holon: Principal Investigator, Yehezkiel Kishon, MD, Physician, Ron Narinsky, MD (deceased).
Coordinating Center. Neufeld Cardiac Research Institute, Sheba Medical Center, Tel Hashomer: Solomon Behar, MD (Director), Uri Goldbourt, PhD, Henrietta Reicher-Reiss, MD, Lori Mandelzweig, MPH.
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- coronary artery bypass graft surgery
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- Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries
- percutaneous transluminal coronary angioplasty
- Secondary Prevention Reinfarction Israeli Nifedipine Trial
- Received November 19, 1996.
- Revision received July 15, 1997.
- Accepted August 5, 1997.
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