Randomized controlled trial of late in-hospital angiography and angioplasty versus conservative management after treatment with recombinant tissue-type plasminogen activator in acute myocardial infarction

An early invasive strategy versus ischemia-guided management after fibrinolytic therapy for ST-segment elevation myocardial infarction: a meta-analysis of contemporary randomized controlled trials

BACKGROUND

Although the use of an early invasive strategy among patients with ST-segment elevation myocardial infarctions (STEMI) who are treated initially with fibrinolytic therapy is common, the safety and efficacy of this approach remains uncertain. We performed a meta-analysis to best estimate the benefits and harms of an early invasive strategy in STEMI patients treated initially with full-dose intravenous fibrinolytic therapy, as compared to a traditional strategy of ischemia-guided management.

METHODS

We included contemporary randomized controlled trials, defined a priori as those with >50% stent use during percutaneous coronary intervention (PCI). Outcomes extracted from the published results of eligible trials included all-cause mortality, reinfarction, stroke, and in-hospital major bleeding.

RESULTS

We identified 5 contemporary trials enrolling 1,235 patients who met our inclusion criteria. Of the patients randomized to an early invasive strategy, 86% underwent PCI with 87% receiving stents. Follow-up duration ranged from 30 days to 1 year. An early invasive strategy was associated with significant reductions in mortality (odds ratio [OR] 0.55, 95% CI 0.34-0.90) and reinfarction (OR 0.53, 95% CI 0.33-0.86) compared with ischemia-guided management. There were no significant differences in the risk of stroke (OR 1.31, 95% CI 0.42-4.10) or major bleeding (OR 1.41, 95% CI 0.74-2.69).

CONCLUSIONS

An early invasive strategy after fibrinolytic therapy is associated with significant reductions in mortality and reinfarction. Our results suggest a potentially important role for this strategy in the management of STEMI patients but should be confirmed by large randomized trials.

Survival and cardiac remodeling benefits in patients undergoing late percutaneous coronary intervention of the infarct-related artery: evidence from a meta-analysis of randomized controlled trials

OBJECTIVES

Our purpose was to perform a systematic review and meta-analysis of randomized trials comparing percutaneous coronary intervention (PCI) of the infarct-related artery (IRA) with medical therapy in patients randomized >12 h after acute myocardial infarction (AMI).

BACKGROUND

There is ongoing uncertainty about the risk-benefit ratio of late PCI in stable patients with AMI.

METHODS

PubMed, CENTRAL, and other databases were searched (July 2007). Studies were included if they compared PCI with medical management and randomized patients >12 h and up to 60 days after AMI, and were excluded if patients were hemodynamically unstable. Odds ratios (ORs) were pooled for dichotomous outcomes, with all-cause mortality as the primary end point. Left cardiac remodeling parameters were also pooled with generic inverse-variance weighting.

RESULTS

We retrieved 10 studies that enrolled 3,560 patients, with median time from AMI to randomization of 12 days (range 1 to 26 days), and follow-up of 2.8 years (42 days to 10 years). Randomization allocated 1,779 subjects to PCI and 1,781 to medical treatment. There were 112 (6.3%) and 149 (8.4%) deaths in the 2 groups, respectively, yielding significantly improved survival in the PCI group (OR 0.49 [95% confidence interval (CI) 0.26 to 0.94], p = 0.030). These benefits were associated with similarly favorable effects on cardiac remodeling, such as improved left ventricular ejection fraction in the PCI group (+4.4% change [95% CI 1.1 to 7.6], p = 0.009).

CONCLUSIONS

Percutaneous coronary intervention of the IRA performed late (12 h to 60 days) after AMI is associated with significant improvements in cardiac function and survival.

Comparing invasive and noninvasive management strategies for acute myocardial infarction using administrative databases

PURPOSE

The aim of this study was to compare outcomes after acute myocardial infarction between regions with low and high catheterization access.

METHODS

Observational study using administrative databases of patients with acute myocardial infarction in provinces with low (Ontario) and high (Quebec and British Colombia) access to invasive cardiac procedures (ICP, n = 141718). Using instrumental variables to control for confounding, effectiveness of treatment was measured on 1-year mortality among marginal patients (patients for whom treatment is discretionary and highly dependent on access to ICP).

RESULTS

The ICP approach was associated with overall decreased mortality (-11%, 95% CI -13% to -8%) with statistically significant reductions in low-access regions (-16%, 95% CI -21% to -10%). High-access regions (QC -8%, 95% CI -19% to 4%) (BC -2%, 95% CI -12% to 7%) exhibited smaller marginal benefits.

CONCLUSION

The invasive approach benefits all marginal patients, with greater benefits in regions of lower access, indicating a threshold of availability above which further mortality benefits are negligible.

Beyond intravenous thrombolysis

The National Institute of Neurological Disorders and Stroke trial of recombinant tissue plasminogen activator has been considered a landmark study in the acute treatment of ischemic stroke. Unfortunately, only a small percentage of all ischemic stroke patients presents to the hospital in time to receive the drug. Moreover, the recannalization rate of a major artery occlusion, such as the proximal middle cerebral artery or top of the internal carotid artery occlusion, after intravenous (IV) thrombolytic therapy has been disappointingly low. Since the Food and Drug Administration's approval of IV plasminogen activator, there have been numerous randomized clinical trials investigating the safety and efficacy of different thrombolytics administered in various time frames. In addition to the IV administration, efforts have been made in order to study the radiographic as well as clinical effects of intra-arterial (IA) thrombolysis. The combination of IV and IA thrombolysis has been studied. For patients who do not qualify for receiving chemical thrombolysis, new devices have been developed for mechanical thrombectomy. Angioplasty and stenting procedures are being performed more frequently than in the past as one of the treatment modalities for acute ischemic stroke patients. Relentless research effort is being made internationally in order to fight the devastating disease which now goes beyond the conventional IV thrombolysis.

Coronary angiography in the elderly with acute myocardial infarction

BACKGROUND

Despite the high mortality rate in elderly patients with acute myocardial infarction (AMI), the value of coronary angiography (CA) in the elderly has been questioned due to a less favorable outcome. The aim of the study was to determine the prognostic significance of CA on mortality of elderly patients AMI in "real world" practice.

METHODS

The study cohort comprised 1009 elderly (age > or = 75 years) patients with AMI who were derived from three prospective national surveys between 1996 and 2000 in all 25 CCUs operating in Israel. Baseline characteristics, hospital course, management and outcome of 274 (27%) elderly patients who underwent CA during the index hospitalization were compared with 735 (73%) counterpart patients who did not.

RESULTS

Patients who underwent CA were on average 2.2 years younger, and were more often with hyperlipidemia (p<0.0001 for each) and with a history of previous percutaneous coronary intervention (p<0.03) than the control group. They had a more favorable clinical presentation: a higher systolic blood pressure (p<0.04), a better Killip class (p<0.03) and an increased frequency of non-Q wave MI (p<0.03). They developed more often recurrent MI (p=0.002) and re-ischemia (p<0.0001). Variables associated with CA use during the index hospitalization were re-infarction, re-ischemia, the year of the index AMI and the availability of an on-site a catheterization laboratory in the hospital, while a higher age and fibrinolytic therapy decreased the likelihood of CA use. Of the patients who underwent CA, 67% underwent coronary revascularization (either PCI and/or CABG). Crude and adjusted mortality rates at 1 year were significantly lower in patients who underwent CA, as compared to counterparts who did not: 21% vs. 37.3%, respectively (p<0.0001), hazard ratio=0.52 (95% confidence interval 0.38-0.71). The benefit of CA was noted in a wide range of subgroups analyzed.

CONCLUSIONS

In "real world" practice, elderly patients with AMI who undergo CA during hospitalization have a better prognosis at 1 year. Age alone should not be a deterrent to performing CA in elderly patients with AMI. Further large randomized trials are needed to confirm that an invasive approach is beneficial in high-risk elderly patients with AMI.

CONDENSED ABSTRACT

To determine the prognostic significance of coronary angiography (CA) during the course of acute myocardial infarction (AMI) in "real world" practice on mortality of elderly patients, 1009 such patients were studied. Re-infarction, re-ischemia, the year of the index AMI and the availability of an on-site a Cath. Lab. were variables which increased the likelihood of undergoing CA, while a higher age and fibrinolytic therapy decreased this likelihood. The crude and covariate adjusted mortality rates at 1 year were significantly lower in patients who underwent CA in comparison to counterparts who did not: 21% vs. 37.3%, respectively (p<0.0001), hazard ratio 0.52 (95% confidence interval 0.38-0.71). The benefit of CA was noted across a wide range of subgroups analyzed.

Revascularization Compared to Medical Treatment in Patients with Silent vs. Symptomatic Residual Ischemia after Thrombolyzed Myocardial Infarction – The DANAMI Study

AIMS

The aim was to compare the effect of revascularization to conservative treatment in patients with residual silent and with residual symptomatic ischemia following acute myocardial infarction (AMI). The study was a subanalysis of the DANAMI (DANish AMI) randomized study of invasive vs. conservative treatment in patients with inducible ischemia after thrombolysis in AMI.

METHODS AND RESULTS

One thousand and eight patients were randomized to invasive or conservative treatment, stratified by the type of ischemia: silent, i.e. ST depression during an exercise test prior to discharge in 56%, or symptomatic, i.e. chest pain occurring either spontaneously during admission or during the exercise test, with or without ST changes, in 44%. Compared to a conservative strategy, invasive treatment reduced the incidence of nonfatal reinfarction, after in median 2.4 years, in both symptomatic patients (13.3-7.2%, p < 0.006) and patients with silent ischemia (10.1 vs. 5.7%, p < 0.05), and of admissions with unstable angina in symptomatic (44.5-27.6%, p < 0.0001) and silent ischemia (21.6-13.3%, p < 0.0006).

CONCLUSIONS

Compared to conservative strategy, invasive treatment reduces the risk of nonfatal reinfarction and hospital admissions for unstable angina in thrombolyzed post-AMI patients with silent as well as symptomatic exercise-induced ischemia.

Impact of on-site cardiac catheterization on resource utilization and fatal and non-fatal outcomes after acute myocardial infarction

Background

Patterns of care for acute myocardial infarction (AMI) strongly depend on the availability of on-site cardiac catheterization facilities. Although the management found at hospitals without on-site catheterization does not lead to increased mortality, little it known about its impact on resource utilization and non-fatal outcomes.

Methods

We identified all patients (n = 35,289) admitted with a first AMI in the province of Quebec between January 1, 1996 and March 31, 1999 using population-based administrative databases. Medical resource utilization and non-fatal and fatal outcomes were compared among patients admitted to hospitals with and without on-site cardiac catheterization facilities.

Results

Cardiac catheterization and PCI were more frequently performed among patients admitted to hospitals with catheterization facilities. However, non-invasive procedures were not used more frequently at hospitals without catheterization facilities. To the contrary, echocardiography [odds ratio (OR), 2.04; 95% confidence interval (CI), 1.93–2.16] and multi-gated acquisition imaging (OR, 1.24; 95% CI, 1.17–1.32) were used more frequently at hospitals with catheterization, and exercise treadmill testing (OR, 1.02; 95% CI, 0.91–1.15) and Sestamibi/Thallium imaging (OR, 0.93; 95% CI, 0.88–0.98) were used similarly at hospitals with and without catheterization. Use of anti-ischemic medications and frequency of emergency room and physician visits, were similar at both types of institutions. Readmission rates for AMI-related cardiac complications and mortality were also similar [adjusted hazard ratio, recurrent AMI: 1.02, 95% CI, 0.89–1.16; congestive heart failure: 1.02; 95% CI, 0.90–1.15; unstable angina: 0.93; 95% CI, 0.85–1.02; mortality: 0.99; 95% CI, 0.93–1.05)].

Conclusion

Although on-site availability of cardiac catheterization facilities is associated with greater use of invasive cardiac procedures, non-availability of catheterization did not translate into a higher use of non-invasive tests or have an impact on the fatal and non-fatal outcomes available for study in our administrative database.

Reevaluation of routine invasive strategy versus noninvasive testing following uncomplicated ST-elevation myocardial infarction

BACKGROUND AND AIMS

While current guidelines recommend a selective invasive approach after low-risk ST-elevation myocardial infarction (STEMI) treated by thrombolysis, based on noninvasive identification of patients with residual or inducible myocardial ischemia, in many instances physicians employ a strategy of routine angiography. The present study was undertaken to reexamine the correlation between noninvasive testing and coronary angiography in patients recovering from uncomplicated STEMI with regard to detection and management of residual infarct artery stenosis and to identify patients with multivessel (MVD) or high-risk coronary disease.

METHODS

We prospectively performed predischarge exercise testing (ETT) and myocardial perfusion scintigraphy (MPS) prior to routine predischarge coronary angiography in 83/276 consecutive STEMI patients, who after treatment with initial and early thrombolysis, were defined as low risk by ACC/AHA risk classification.

RESULTS

ETT was positive for myocardial ischemia in 11/43 (26%) patients with single-vessel disease (SVD) and 11/22 (50%) patients with MVD, but normal or nondiagnostic in the remainder. MPS revealed significant reversible perfusion defects in 13/40 (32%) patients with SVD and 13/22 (59%) patients with MVD. A selective strategy of ETT followed by MPS for nondiagnostic ETT missed residual infarct-related artery stenosis and/or MVD in 31/81 (38%) of the cohort. Among patients who may not otherwise have been referred for angiography, severe (> or =70%) residual stenosis of the infarct-related artery was present in 56% and MVD in 16%.

CONCLUSIONS

Early predischarge ETT and/or MPS had limited sensitivity for the detection of coronary disease in low-risk post-STEMI patients. The study supports a simpler strategy of routine coronary angiography in most patients after low-risk STEMI.

Invasive versus noninvasive management of ST-elevation acute myocardial infarction: a review of clinical trials and observational studies

BACKGROUND

Despite decades of research, it is still unclear whether patients with uncomplicated ST-segment elevation acute myocardial infarction (AMI) should be managed with an invasive or a noninvasive approach after successful thrombolysis.

METHODS

We reviewed randomized trials in which patients were randomized to a strategy of routine cardiac catheterization after thrombolysis (invasive) or a strategy whereby patients received cardiac catheterization only if they demonstrated reversible ischemia by noninvasive testing (noninvasive). We also reviewed observational studies that compared outcomes for patients who were admitted to hospitals with and without availability of cardiac catheterization facilities or in different geographic regions.

RESULTS

Evidence to date suggests that invasive approach does not result in mortality or reinfarction benefits for patients with uncomplicated ST-segment elevation AMI. However, all except one of the trials performed are dated in view of recent treatment advances, and long-term outcomes for the recent trial have not been published. Several observational studies suggest that the invasive approach may improve "softer" outcomes such as quality of life and functional status.

CONCLUSION

In conclusion, there is currently no evidence to support widespread use of the invasive approach among patients with uncomplicated ST-segment elevation AMI. However, trials with long-term follow-up should be repeated in the current clinical context and should include both hard and softer outcome measures.

Les syndromes coronariens aigus avec sus-décalage du segment ST

UNBLOCK THE CORONARY ARTERIES: For the treatment of acute coronary syndromes with ST-segment elevation, emergency repermeabilisation is of the artery is crucial, generally by primary angioplasty than by fibrinolysis. The other treatments have little beneficial effects on mortality. Primary angioplasty is the technique of choice when it can be performed in the intensive care units with staff with sufficient experience and within the 90 minutes following the preliminary medical management, and benefiting from the supply of PG IIb-IIIa. THROMBOLYSIS: Performed before the twelfth hour, thrombolysis reduces mortality. The earlier it is performed the greater the benefits. A significant reduction is mortality is observed even in patients aged over 75. The indications for coronography are determined by the existence of clinical risk factors and by the data of supplementary non-invasive examinations (sonography, scintigraphy, effort testing). When clinical risk factors exist from the start, a coronography must be performed. In the absence of initial risks, and if the non-invasive examination reveals risk factors, then a coronarography should be performed.

Does aggressive care following acute myocardial infarction reduce mortality? Analysis with instrumental variables to compare effectiveness in Canadian and United States patient populations

BACKGROUND

Previous U.S. studies suggest that the incremental ("marginal") use of the aggressive approach to care for acute myocardial infarction (AMI) in patients differing only in their distance to hospitals offering aggressive care may be associated with small mortality benefits. We hypothesized that the marginal benefits should be larger in Canada, as the country is operating on a lower margin because the approach to care is more conservative overall.

METHODS

This retrospective study used administrative data of hospital admissions and health services for all patients admitted for a first AMI in Quebec in 1988 (n = 8,674). We used differential distances to hospitals offering aggressive care as instrumental variables when measuring mortality up to four years after AMI.

RESULTS

Of the 4,422 subjects who were > or = 65 years old, 11 percent received cardiac catheterization within 90 days after admission. In a previous study that applied similar methodology to the 1987 U.S. Medicare population, 23 percent of subjects received catheterization within 90 days. As in the U.S. study, we found that subjects living closer to hospitals offering aggressive care were more likely to receive aggressive care than subjects living further away (26 percent versus 19 percent received cardiac catheterization within 90 days; 95 percent CI: 5 percent to 9 percent). Unlike the U.S. study, we found no differences in mortality across the "close" versus "far" differential distance groups (unadjusted differences at one year: 1 percent; 95 percent CI: -1 percent to 3 percent). This absence of association held in elderly (> or = 65 years) and younger age groups. Adjusted results also showed no differences between subjects receiving aggressive versus conservative care (at one year: 4 percent; 95 percent CI: -11 percent to 20 percent).

CONCLUSIONS

Contrary to our hypothesis, but consistent with results from numerous randomized trials and observational studies, we cannot confirm that, on the margin, the aggressive approach to post-AMI care is associated with mortality benefits in Canada.

Early reperfusion and late clinical outcomes in patients presenting with acute myocardial infarction randomly assigned to primary percutaneous coronary intervention or streptokinase

BACKGROUND

Primary percutaneous coronary intervention (PCI) has become an alternative to thrombolytic therapy as a reperfusion strategy for ST-elevation acute myocardial infarction (AMI).

METHODS

The main goal of this study was to determine whether PCI and thrombolytic therapy achieve comparable reperfusion rates, as evidenced by ST-segment resolution. Secondary end points included infarct vessel patency rates before hospital discharge and short- and long-term outcomes. Patients with ischemic chest pain with duration < or =12 hours and no contraindication for thrombolytic therapy were included.

RESULTS

Between October 1993 and August 1995, 58 patients were randomly assigned to streptokinase (SK) and 54 patients to primary PCI. Baseline clinical characteristics and infarct location were well balanced in both groups. Median age (interquartile range) was 68 (58, 75) years, 29% were women, and 78% of the patients met at least one criterion for "not low risk" AMI (anterior location, age >70 years old, previous MI, systolic blood pressure <100 mm Hg, and/or heart rate >100 bpm). The median time from symptom onset to random assignment was 217 (139, 335) minutes in the PCI group and 210 (145, 334) minutes in the SK group. Median random assignment to balloon time was 82 (55, 100) minutes, and median random assignment to needle time was 15 (10, 26) minutes (P <.0001). TIMI grade 3 flow after primary PCI was obtained in 85% of patients. The proportion of patients with ST-segment resolution > or =50% at 120 minutes was 80% in the PCI group and 50% in the SK group (P =.001). The predischarge angiogram showed the presence of TIMI 3 flow in 96% of patients who received PCI and 65% of patients who received SK (P <.001). A composite of in-hospital death, reinfarction, severe heart failure, stroke, and major bleeding occurred in 15% of patients who received PCI and 21% of patients who received SK (P =.4). At 3 years, freedom from the composite end point of AMI, postdischarge revascularization, and death was 61% in the PCI group and 40% in the SK group (P =.025).

CONCLUSIONS

Our study shows that primary PCI, as compared with SK, is associated with more effective ST-segment resolution, higher patency rates in the infarct vessel at 7 days, and more favorable clinical outcomes at 3 years of follow-up.

Glycoprotein IIb/IIIa inhibition in early intent-to-stent treatment of acute coronary syndromes: EPISTENT, ADMIRAL, CADILLAC, and TARGET

The acute coronary syndromes (ACS), with or without ST-segment elevation, share a common pathophysiology of activated platelets and thrombin generation stimulated by plaque erosion and rupture. Both mechanical and pharmacologic treatment strategies have evolved in an attempt to improve reperfusion at the myocardial tissue level. Intracoronary stents have lowered the incidence of abrupt vessel closure and restenosis, while potent platelet inhibition from intravenous glycoprotein IIb/IIIa antagonists has reduced the rate of periprocedural myocardial infarction and late mortality. Abciximab has well-established clinical benefits in percutaneous revascularization trials, and several recent landmark studies have evaluated the efficacy of concomitant abciximab during mechanical reperfusion therapy in the setting of ACS. These trials are reviewed, and an overall perspective is provided.

Outcomes research in the development and evaluation of practice guidelines

BACKGROUND

Practice guidelines have been developed in response to the observation that variations exist in clinical medicine that are not related to variations in the clinical presentation and severity of the disease. Despite their widespread use, however, practice guideline evaluation lacks a rigorous scientific methodology to support its development and application.

DISCUSSION

Firstly, we review the major epidemiological foundations of practice guideline development. Secondly, we propose a chronic disease epidemiological model in which practice patterns are viewed as the exposure and outcomes of interest such as quality or cost are viewed as the disease. Sources of selection, information, confounding and temporal trend bias are identified and discussed.

SUMMARY

The proposed methodological framework for outcomes research to evaluate practice guidelines reflects the selection, information and confounding biases inherent in its observational nature which must be accounted for in both the design and the analysis phases of any outcomes research study.

Defining the role of abciximab for acute coronary syndromes: lessons from CADILLAC, ADMIRAL, GUSTO IV, GUSTO V, and TARGET

Acute coronary syndromes (ACS), including those associated with or without ST-segment elevation, share a common pathophysiology mediated by activated platelets and thrombin. It is becoming increasingly appreciated that reperfusion therapies using primary mechanical or pharmacologic strategies result in suboptimal reperfusion at the myocardial tissue level. Complete reperfusion of the coronary microvasculature has recently been shown to be an important predictor for survival following myocardial infarction. Abciximab has well-established clinical benefits in numerous interventional trials. Through its anti-platelet and anti-thrombotic activities, abciximab reduces thrombus formation and hence minimizes risk of thrombotic microvascular embolization and improves tissue-level reperfusion. Several recent landmark trials have evaluated the clinical efficacy of adjunctive abciximab during mechanical or pharmacologic reperfusion therapy in the setting of ACS. This article provides an update of the role of abciximab in the treatment for ACS based on the results of these clinical trials.

Age and the utilization of cardiac catheterization following uncomplicated first acute myocardial infarction treated with thrombolytic therapy (The Second National Registry of Myocardial Infarction [NRMI-2])

Considerable data indicates that patients <50 years of age have lower morbidity and mortality after acute myocardial infarction (AMI) than older patients. It has been demonstrated that use of routine cardiac catheterization and revascularization in younger patients with AMI and successful thrombolysis does not confer benefit compared with a more conservative approach. Despite this, it has been our impression that cardiac catheterization is frequently employed in younger patients with AMI. Patients with uncomplicated initial AMI treated with thrombolytic therapy in the Second National Registry of Myocardial Infarction (NRMI-2) between June 1994 and April 1998 were identified. Patients were categorized into 4 age strata for purposes of analysis. A total of 61,232 cases met our inclusion criteria. Cardiac catheterization was performed during hospitalization in 78% of patients after an uncomplicated initial AMI. Age was inversely associated with receipt of cardiac catheterization: 85% of those < or =49 years old underwent catheterization compared with 63% of those > or =70 years old. Regression analysis revealed that use of catheterization was 2.9 times greater (95% confidence intervals 2.7 to 3.2) in patients < or =49 years old compared with those > or =70 years old. Geographic location and payor status also strongly influenced utilization of this procedure. In conclusion, routine coronary angiography after uncomplicated AMI is extensively utilized in all age groups, particularly in those <50 years of age. The efficacy and cost effectiveness of this strategy in these patients has not yet been determined in clinical trials.

What are appropriate rates of invasive procedures following acute myocardial infarction? A systematic review

OBJECTIVE

To assess the evidence that higher rates of coronary angiography (CA) and revascularisation (RV) in the subacute phase of acute myocardial infarction (AMI) improve patient outcomes.

DATA SOURCES

MEDLINE 1990 - December 1999, Current Contents 1990-1999, Cochrane Library (Issue 4, 1999), HealthSTAR 1990-1999, selected websites and bibliographies of retrieved articles.

STUDY SELECTION AND DATA EXTRACTION

Studies selected were (1) randomised trials comparing outcomes of "invasive" versus "conservative" use of CA and RV following AMI; (2) observational studies with formal methods comparing outcomes of high versus low rates of use of these procedures; and (3) clinical practice guidelines (CPGs), expert panel statements and decision analyses which met critical appraisal criteria, and which specified procedural indications. Outcome measures were rates of mortality, re-infarction and limiting or unstable angina.

DATA SYNTHESIS

56 articles were identified; 24 met inclusion criteria. Pooled data from nine RCTs of "invasive" (CA rate 96%; RV rate 66%) versus "conservative" (CA rate 28%; RV rate 19%) strategies showed no significant differences in mortality or re-infarction rates. Pooled results from 12 observational studies showed no mortality differences, but an excess reinfarction rate (8.0% vs 6.4%; P<0.001) in high- versus low-rate populations. Evidence of survival benefit from procedural intervention was strongest for patients with recurrent ischaemia combined with left ventricular dysfunction.

CONCLUSIONS

In the subacute phase of AMI, rates of CA and RV in excess of 30% and 20%, respectively, may not confer additional benefit in preventing death or re-infarction. However, variability between studies in design, patient selection, and extent of cross-over from medical to procedural groups, as well as limited data on symptom status, limits generalisability of results.

Improved survival of patients with acute myocardial infarction with significant left ventricular dysfunction undergoing invasive coronary procedures

BACKGROUND

Acute myocardial infarction (AMI) associated with significant left ventricular dysfunction (LVD) indicates a poor prognosis. Previous studies suggested that revascularization improves survival of patients with AMI complicated by cardiogenic shock. However, other studies that suggested that revascularization improves survival of stable patients with significant LVD did not specifically address patients who had recently had an AMI.

OBJECTIVES

Our purpose was to determine whether patients with thrombolysis-treated AMI associated with significant LVD are likely to incur a survival advantage from catheterization and coronary revascularization performed within 30 days after AMI.

METHODS

The study population was drawn from the Argatroban in Acute Myocardial Infarction-2 (ARGAMI-2) trial, which included 1200 patients with AMI, all of whom received thrombolytic therapy. Our analysis included 737 patients for whom LV function was estimated by echocardiography. Two hundred two patients had significant LVD; of them, 117 (58%) underwent cardiac catheterization and 85 were treated noninvasively. Among 535 patients without significant LVD, 291 (54%) underwent cardiac catheterization and 244 were treated noninvasively.

RESULTS

Compared with a noninvasive approach, an invasive approach resulted in reduced 30-day and 6-month mortality rates in patients with significant LVD: 4.3% versus 10.6%, adjusted odds ratio (OR) 0.26, 95% confidence interval (CI) 0.04 to 1.18, and 6.1% versus 15.5%, OR 0.27, 95% CI 0.06 to 0.98, respectively. A similar comparison in patients without significant LVD resulted in comparable 30-day and 6-month mortality rates for both patient groups: invasively versus noninvasively treated, 0.7% versus 0.8%, OR 1.04, 95% CI 0.04 to 12.7, and 1.4% versus 1.7%, adjusted OR 1.60, 95% CI 0.20 to 9.87.

CONCLUSIONS

The current study suggests that AMI patients with significant LVD may benefit from cardiac catheterization and revascularization performed early after AMI, whereas in patients without significant LVD the outcome of those treated invasively or conservatively was similar.

Health related quality of life after conservative or invasive treatment of inducible postinfarction ischaemia. DANAMI study group

OBJECTIVE

To assess health related quality of life in patients with inducible postinfarction ischaemia.

DESIGN

A questionnaire based follow up study on patients randomised to conservative or invasive treatment because of postinfarction ischaemia.

SETTING

Seven county hospitals in eastern Denmark and the Heart Centre, National University Hospital, Copenhagen, Denmark.

PATIENTS

113 patients with inducible postinfarction ischaemia: 51 were randomised to conservative treatment and 62 to invasive treatment. Average follow up time was three years (19-57 months).

MAIN OUTCOME MEASURES

SF-36, Rose angina and dyspnoea questionnaire, drug use, lifestyle, and cognitive function.

RESULTS

Invasively treated patients scored better on the SF-36 scales of physical functioning (p = 0.03) and on role-physical (p = 0.04) and physical component scales (p = 0.05) and took significantly less anti-ischaemic drug treatment. Angina occurred in 18% of the invasively treated patients and 31% of the conservatively treated patients (p = 0.09). However, more invasively treated patients suffered from concentration difficulties (18% v 4%; p = 0.04).

CONCLUSIONS

Patients who were treated invasively had better health related quality of life scores in the physical variables compared with conservatively treated patients. However, a larger proportion of invasively treated patients had concentration difficulties.

Support for the open-artery hypothesis in survivors of acute myocardial infarction: analysis of 11,228 patients treated with thrombolytic therapy

We examined the possible benefits of achieving and maintaining infarct-related artery potency beyond the time when preservation of left ventricular function would be expected. The open-artery hypothesis suggests that a patent infarct-related artery confers a survival benefit greater than that expected from myocardial salvage alone, which extends beyond the time when preservation of left ventricular function is expected. We examined the survival experience of patients undergoing thrombolysis in the Global Utilization of Streptokinase and TPA for Occluded Arteries (GUSTO-I) trial for whom data on the potency of the infarct artery were available. Univariable analysis was used to determine the unadjusted relations of angiographic variables and revascularization procedures to both 30-day and 1-year mortality in 30-day survivors. Multivariable analysis was used to test for interactions between patency and each characteristic and to adjust both for all other variables and for baseline characteristics known to predict mortality. In both univariable and multivariable analysis, patients with an open rather than a closed infarct-related artery had significantly lower 30-day mortality (p <0.001). This benefit cannot be accounted for by myocardial salvage alone, because it remained after adjustment for left ventricular ejection fraction. Patency was also associated with lower 1-year mortality in 30-day survivors, but not after adjustment for other variables affecting late mortality. Having an open infarct-related artery at the time of first catheterization confers a survival advantage that extends beyond the benefit of myocardial salvage from thrombolytic therapy, and is independent of ejection fraction.

Intervention with PTCA and CABG following thrombolysis for acute myocardial infarction. Australian data from GUSTO 1 (1991-3) and International Study Group r-TPA-Streptokinase Mortality (1989) trials. Global Utilisation of Streptokinase and Tissue

The patterns of revascularisation with percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass graft (CABG) surgery in the GUSTO 1 trial patients in Australia are described. In comparison with rates documented in earlier trials of thrombolytic therapy in Australia, the rates of revascularisation post-thrombolysis increased by 50%, primarily due to a doubling in the rate of use of PTCA. However, the rates were low by international comparisons. There were marked variations in the rates of revascularisation between States, but no correlation with differences in mortality between States. The main predictors of post thrombolysis PTCA were prior angina, mild infarction and access to PTCA facilities.

[Is the exercise test performed after myocardial infarct really useful in improving prognosis? Arguments in favor]

The evaluation of risk after myocardial infarction accomplishes two objectives: a) selecting patients with high-risk for coronary angiography and revascularization, and b) identifying low-risk patients to avoid unnecessary laboratory investigation and revascularization procedures. Currently, patients eligible for exercise test are those with no evidence of heart failure or angina, and with a preserved left ventricular function. Overall prognosis for such patients, especially if they were thrombolyzed, is very good. In this setting, in contrast to that pointed out in previous reports, the positive predictive value of exercise electrocardiography is very low (i.e., a patient with S-T depression has a probability of cardiac death in the ensuing year of only 4% vs 2% if the test is negative). This suggests that a routine postinfarction exercise test is inefficient from a prognostic point of view. However, a recent study has shown that thrombolyzed patients with a positive response to the exercise test, have a significantly lower rate of reinfarction and unstable angina when they undergo myocardial revascularization. Mortality rate, as it was low in the study population, was unchanged by the use of revascularization procedures. We conclude that, in spite of the limitations pointed out, there are at least two reasons to continue performing exercise tests in all uncomplicated infarctions: a) a negative test, due to its high negative predictive value for adverse events, reassures the patient and his family and prompts an early discharge, and b) some patients, despite an uncomplicated in-hospital evolution, have a "strong" positive response that suggests multivessel disease and a possible benefit from myocardial revascularization.

Routine Coronary Arteriography Following Thrombolytic Therapy for Acute Myocardial Infarction: An Unsettled Controversy

Although coronary artery disease remains the leading cause of death in industrialized countries, the management of patients recovering from acute myocardial infarction varies significantly. The issue of routine arteriography and revascularization following thrombolytic therapy remains controversial despite substantial evidence associating infarct-related artery patency with improved cardiac function and survival. Randomized trials of routine intervention after myocardial infarction have generally failed to demonstrate advantages of this invasive approach but methodological problems limit their application to current practice. High-risk patients should be referred for arteriography. While awaiting definitive trials addressing the influence of routine arteriography on patient survival and its cost effectiveness, the management of other patient groups must be individualized.

Safety and cost-effectiveness of early discharge after primary angioplasty in low risk patients with acute myocardial infarction. PAMI-II Investigators. Primary Angioplasty in Myocardial Infarction

OBJECTIVES

The second Primary Angioplasty in Myocardial Infarction (PAMI-II) study evaluated the hypothesis that primary percutaneous transluminal coronary angioplasty (PTCA), with subsequent discharge from the hospital 3 days later, is safe and cost-effective in low risk patients.

BACKGROUND

In low risk patients with myocardial infarction (MI), few data exist regarding the need for intensive care and noninvasive testing or the appropriate length of hospital stay.

METHODS

Patients with acute MI underwent emergency catheterization with primary PTCA when appropriate. Low risk patients (age <70 years, left ventricular ejection fraction >45%, one- or two-vessel disease, successful PTCA, no persistent arrhythmias) were randomized to receive accelerated care (admission to a nonintensive care unit and day 3 hospital discharge without noninvasive testing [n = 237] or traditional care [n = 234]).

RESULTS

Patients who received accelerated care had similar in-hospital outcomes but were discharged 3 days earlier (4.2+/-2.3 vs. 7.1+/-4.7 days, p = 0.0001) and had lower hospital costs ($9,658+/-5,287 vs. $11,604+/-6,125 p = 0.002) than the patients who received traditional care. At 6 months, accelerated and traditional care groups had a similar rate of mortality (0.8% vs. 0.4%, p = 1.00), unstable ischemia (10.1% vs. 12.0%, p = 0.52), reinfarction (0.8% vs. 0.4%, p = 1.00), stroke (0.4% vs. 2.6%, p = 0.07), congestive heart failure (4.6% vs. 4.3%, p = 0.85) or their combined occurrence (15.2% vs. 17.5%, p = 0.49). The study was designed to detect a 10% difference in event rates; at 6 months, only a 2.3% difference was measured between groups, indicating an actual power of 0.19.

CONCLUSIONS

Early identification of low risk patients with MI allowed safe omission of the intensive care phase and noninvasive testing, and a day 3 hospital discharge strategy, resulting in substantial cost savings.

Prognostic significance of ST segment shift early after resolution of ST elevation in patients with myocardial infarction treated with thrombolytic therapy: the GUSTO-I ST Segment Monitoring Substudy

OBJECTIVES

We sought to study the relation between recurrent ST segment shift within 6 to 24 h of initial resolution of ST elevation after thrombolytic therapy and 30-day and 1-year mortality.

BACKGROUND

Rapid and stable resolution of ST segment elevation in relation to thrombolytic therapy in patients with an acute myocardial infarction is an indicator of culprit artery patency. Whether recurrence of ST segment shift during continuous ST monitoring after initial resolution is related to poor prognosis has not been studied.

METHODS

ST segment monitoring was performed within 30 min after thrombolytic therapy for acute myocardial infarction. The predictive value of a new ST segment shift (assessed as > or = 0.1-mV deviation from the baseline) 6 to 24 h after thrombolytic therapy was studied with respect to 30-day and 1-year mortality.

RESULTS

Of 734 patients, 243 had a new ST segment shift (33%). The 30-day mortality rate in patients with an ST shift (7.8%) was significantly higher than that in patients without an ST shift (2.25%, p = 0.001), as was the 1-year mortality rate (10.3% vs. 5.7%, respectively, p = 0.025). Multivariable analysis revealed an independent predictive value of ST shift with respect to 30-day mortality (p = 0.008), even after consideration of multiple clinical risk factors in the overall Global Utilization of Streptokinase and TPA for Occluded Coronary Arteries (GUSTO)-I mortality model (p = 0.0001). Moreover, the duration of the ST shift bore a direct relation with 1-year mortality (p = 0.008).

CONCLUSIONS

Detection of ST segment shift early after thrombolytic therapy for acute myocardial infarction is a simple, noninvasive means of identifying patients at high risk and is superior to other commonly assessed clinical risk factors. Thus, patients with a new ST shift after the first 6 h, but within 24 h, represent a high risk group that may benefit from more aggressive intervention, whereas patients without evidence of an ST shift represent a low risk subgroup.

Delayed percutaneous transluminal coronary angioplasty after acute myocardial infarction

The value of delayed percutaneous transluminal coronary angioplasty (> 12 h from admission or after thrombolytic therapy) following acute myocardial infarction is controversial. We compared the short- and long-term prognosis of 1940 consecutive patients after acute myocardial infarction, of whom 188 underwent delayed percutaneous transluminal coronary angioplasty. Delayed percutaneous transluminal coronary angioplasty was more frequently done in patients treated with thrombolysis (12%) than among patients excluded from thrombolytic therapy (8%; P=0.005). Patients in the delayed percutaneous transluminal coronary angioplasty group were younger, included more men and smokers and had less in-hospital complications in comparison to patients who did not undergo delayed percutaneous transluminal coronary angioplasty. The crude 30-day and 1-year mortality rates were 3 and 6% among patients who underwent percutaneous transluminal coronary angioplasty vs. 14 and 21% (P<0.01 for each) among those without percutaneous transluminal coronary angioplasty, respectively. After multivariate analysis adjusted for confounding factors, delayed percutaneous transluminal coronary angioplasty was associated with 65 (RR=0.35; 90% CI 0.14-0.88) and 50% (RR=0.50; 90% CI 0.27-0.92) mortality risk reduction after 30 days and 1 year, respectively. In conclusion, delayed percutaneous transluminal coronary angioplasty applied to selected post-myocardial infarction patients upon clinical indication is safe and beneficial for the treatment of acute myocardial infarction in the community.

Danish multicenter randomized study of invasive versus conservative treatment in patients with inducible ischemia after thrombolysis in acute myocardial infarction (DANAMI). DANish trial in Acute Myocardial Infarction

BACKGROUND

The aim of the DANish trial in Acute Myocardial Infarction (DANAMI) study was to compare an invasive strategy of percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass grafting (CABG) with a conservative strategy in patients with inducible myocardial ischemia who received thrombolytic treatment for a first acute myocardial infarction (AMI).

METHODS AND RESULTS

Of the 503 patients randomized to an invasive strategy, PTCA was performed in 266 (52.9%) and CABG in 147 (29.2%) from 2 to 10 weeks after the AMI. Of the 505 patients in the conservative treatment group, only 8 (1.6%) had been revascularized 2 months after the AMI. The patients were followed up from 1 to 4.5 years. The primary end points were mortality, reinfarction, and admission with unstable angina. At 2.4 years' follow-up (median), mortality was 3.6% in the invasive treatment group and 4.4% in the conservative treatment group (not significant). Invasive treatment was associated with a lower incidence of AMI (5.6% versus 10.5%; P=.0038) and a lower incidence of admission for unstable angina (17.9% versus 29.5%; P<.00001). The percentages of patients with a primary end point were 15.4% and 29.5% at 1 year, 23.5% and 36.6% at 2 years, and 31.7% versus 44.0% at 4 years (P=<.00001) in the invasive and conservative treatment groups, respectively. At 12 months, stable angina pectoris was present in 21% of patients in the invasive treatment group and 43% in the conservative treatment group.

CONCLUSIONS

Invasive treatment in post-AMI patients with inducible ischemia results in a reduction in the incidence of reinfarction, fewer admissions due to unstable angina, and lower prevalence of stable angina. We conclude that patients with inducible ischemia before discharge who have received treatment with thrombolytic drugs for their first AMI should be referred to coronary arteriography and revascularized accordingly.

Thrombolytic therapy for patients with prior percutaneous transluminal coronary angioplasty and subsequent acute myocardial infarction. GUSTO-I Investigators. Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries

Our purpose was to evaluate the outcomes of patients with prior coronary angioplasty who underwent thrombolysis for new acute myocardial infarction (AMI) in the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries-I trial. Baseline characteristics and clinical outcomes were compared between patients with (n = 1,647) and without (n = 39,150) previous angioplasty. The relations among prior angioplasty, clinical outcomes, and treatment effects were examined with logistic regression modeling. Patients with previous angioplasty tended to be younger and presented sooner after symptom onset, but had more multivessel disease and lower ejection fractions. Unadjusted mortality was significantly lower in the prior-angioplasty group at 24 hours (1.8% vs 2.7%, p = 0.03) and 30 days (5.6% vs 7.0%, p = 0.036). Although most of the survival advantage was due to low-risk characteristics in this group (lower age and heart rate and fewer anterior wall AMIs), prior angioplasty remained a weak but independent predictor of survival. Recurrent ischemia and reinfarction occurred more often in the prior-angioplasty group, as did bypass surgery (12.2% vs 8.5%) and repeat angioplasty (34.5% vs 21.4%). Patients with prior angioplasty and prior AMI had lower 30-day mortality than those with prior infarction alone (6.3% vs 12.6%, p < 0.01). Treatment effects on 30-day mortality were similar among patients with prior angioplasty (odds ratio 1.2 for accelerated tissue-plasminogen activator v. combined streptokinase arms, 95% confidence interval 0.73 to 1.9). Patients with prior angioplasty who present with AMI have fewer in-hospital adverse events and lower 30-day mortality than those without such a history.

Determinants of the use of coronary angiography and revascularization after thrombolysis for acute myocardial infarction

BACKGROUND

Clinical trials and practice guidelines have identified clinical criteria for the use of coronary angiography and revascularization procedures after thrombolysis for acute myocardial infarction. The effect of these criteria on clinical practice has not been extensively evaluated.

METHODS

We used classification-and-regression-tree (CART) and logistic-regression models to study the patients in the first Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries trial, to identify the variables that best predicted the use of angiography and revascularization procedures after thrombolysis.

RESULTS

Among the 21,772 U.S. patients in the trial, 71 percent underwent coronary angiography before discharge from the hospital. Of these, 58 percent underwent revascularization (73 percent receiving angioplasty). The CART model for the use of angiography showed that age was the variable most predictive of angiography; only 53 percent of patients at least 73 years of age underwent angiography, as compared with 76 percent of those under 73. Among the older patients, age was again the most predictive factor; among the younger patients, the availability of angioplasty was a more important predictor (67 percent of patients in hospitals without angioplasty facilities underwent angiography, as compared with 83 percent in hospitals with such facilities). The next most important variable was recurrent ischemia, which was more predictive at hospitals without angioplasty facilities than at those with them. Both statistical models identified coronary anatomy as the most important predictor of the use and type of revascularization.

CONCLUSIONS

More patients treated with thrombolysis underwent angiography and revascularization before discharge than might be expected. Younger age and the availability of the procedures appeared to be the major determinants of the use of coronary angiography, whereas coronary anatomy largely determined the use and type of revascularization. This process appeared to select low-risk patients for intervention rather than those at higher risk, who would be the most likely to benefit.

Effects of platelet glycoprotein IIb/IIIa receptor blockade by a chimeric monoclonal antibody (abciximab) on acute and six-month outcomes after percutaneous transluminal coronary angioplasty for acute myocardial infarction. EPIC investigators

Percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction is an attractive alternative to thrombolysis, but is still limited by recurrent ischemia and restenosis. We determined whether adjunctive platelet glycoprotein IIb/IIIa receptor blockade improved outcomes in patients undergoing direct and rescue PTCA in the Evaluation of c7E3 for Prevention of Ischemic Complications (EPIC) trial. Of the 2,099 patients undergoing percutaneous intervention who randomly received chimeric 7E3 Fab (c7E3) as a bolus, a bolus and 12-hour infusion, or placebo, 42 underwent direct PTCA for acute myocardial infarction and 22 patients had rescue PTCA after failed thrombolysis. The primary composite end point comprised death, reinfarction, repeat intervention, or bypass surgery. Outcomes were assessed at 30 days and 6 months. Baseline characteristics were similar in direct and rescue PTCA patients. Pooling the 2 groups, c7E3 bolus and infusion reduced the primary composite end point by 83% (26.1% placebo vs 4.5% c7E3 bolus and infusion, p = 0.06). No reinfarctions or repeat urgent interventions occurred in c7E3 bolus and infusion patients at 30 days, although there was a trend toward more deaths in c7E3-treated patients. Major bleeding was increased with c7E3 (24% vs 13%, p = 0.28). At 6 months, ischemic events were reduced from 47.8% with placebo to 4.5% with c7E3 bolus and infusion (p = 0.002), particularly reinfarction (p = 0.05) and repeat revascularization (p = 0.002). We conclude that adjunctive c7E3 therapy during direct and rescue PTCA decreased acute ischemic events and clinical restenosis in the EPIC trial. These data provide initial evidence of benefit for glycoprotein IIb/IIIa receptor blockade during PTCA for acute myocardial infarction.

Regional variation across the United States in the management of acute myocardial infarction. GUSTO-1 Investigators. Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries

BACKGROUND

Differences in the management of acute myocardial infarction have been reported among countries, but few studies have investigated this issue in regions of the United States.

METHODS

We compared the management of acute myocardial infarction among census regions across the United States, using data from the first Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries trial (GUSTO-1) comprising 21,772 patients, and from the American Hospital Association.

RESULTS

We found substantial regional variation in the management of acute myocardial infarction in the United States. Beta-blockers (prescribed for a range of 55 to 81 percent of patients in the various regions), nitrates (prescribed for 61 to 77 percent), and angiotensin-converting-enzyme inhibitors (prescribed for 18 to 23 percent) were used most often in New England, whereas calcium-channel blockers (31 to 42 percent) and lidocaine (14 to 43 percent) were used least often there. Similarly, the proportion of patients undergoing various cardiac procedures differed among regions (range for angiography, 52 to 81 percent of patients; angioplasty, 22 to 35 percent; and coronary-artery bypass surgery, 9 to 17 percent) and was lowest in New England. The regional use of cardiac procedures was closely related to their availability, except in New England. After the analysis was adjusted for clinical and hospital variables, patients in New England were found to be less likely to undergo angiography than patients in the other regions (odds ratio, 0.37; 95 percent confidence interval, 0.32 to 0.42). There was no apparent relation between the use of cardiac procedures and rates of recurrent infarction or death at 30 days or 1 year.

CONCLUSIONS

There is substantial regional variation in the use of cardiac medications and procedures to manage acute myocardial infarction in the United States. The use and availability of cardiac procedures are closely related. The management of acute myocardial infarction in New England is atypical in that the relatively limited availability of cardiac procedures does not account for their relatively low use in that region.

Contemporary management of acute myocardial infarction

Acute myocardial infarction, the leading cause of death in western society, has been the focus of more randomized clinical trial effort over the past decade than any other area of medicine. As a result of this worldwide effort, involving hundreds of thousands of patients with myocardial infarction, data have accumulated showing substantially lower mortality of acute myocardial infarction with simple interventions such as i.v. thrombolytic therapy, aspirin, beta-blockers, and angiotensin-converting enzyme inhibitors. Emergency coronary angioplasty appears to be a suitable alternative to i.v. thrombolytic therapy in skilled centers. Several previously recommended therapies (routine i.v. lidocaine, calcium channel blockers, magnesium, nitrates) have not been proved to be life-saving. Whether routine coronary arteriography should be employed after myocardial infarction remains controversial, but it is generally accepted that patients with evidence of residual ischemia after infarction, either spontaneous or provoked by stress testing, should undergo prophylactic coronary revascularization.

Does PTCA in acute myocardial infarction affect mortality and reinfarction rates? A quantitative overview (meta-analysis) of the randomized clinical trials

BACKGROUND

Percutaneous transluminal coronary angioplasty (PTCA) is often performed after acute myocardial infarction (AMI) either as an adjuvant to thrombolytic therapy or instead of thrombolysis. The effect of PTCA in AMI on mortality and reinfarction has remained unclear, with the available randomized trials indicating inconsistent results.

METHODS AND RESULTS

A systematic overview (meta-analysis) of the randomized trials was conducted to assess the effect of PTCA in AMI on mortality and reinfarction rates. Data from 7 trials in which primary PTCA was evaluated and 16 trials in which PTCA after thrombolysis was studied were included in this overview, comprising a total of 8496 patient. The trials represented different approaches to the timing of PTCA after AMI. The trials of PTCA after thrombolytic therapy were also categorized according to the different protocols with respect to the routine or elective character of PTCA in the invasive group. A reduction in short-term (6 week) mortality (odds ratio, 0.56; 95% CI, 0.33, 0.94) and in the combined outcome of short-term mortality and nonfatal reinfarction (odds ratio, 0.53; 95% CI, 0.35, 0.80) was observed in the trials comparing primary PTCA with thrombolytic therapy. In contrast, in trials in which an approach of thrombolysis and PTCA was compared with thrombolytic therapy alone, there was no important difference in early mortality, with an apparent reduction in mortality between 6 and 52 weeks. The lower mortality between 6 and 52 weeks among 6-week survivors seemed to be restricted to the subgroup of trials in which PTCA was used as a routine strategy (odds ratio, 0.58; 95% CI, 0.39, 0.87).

CONCLUSIONS

Although the analyses of the various categories of trials suggest that primary PTCA may be more beneficial than thrombolytic therapy in AMI, these data should be interpreted cautiously unless confirmed by larger studies. In contrast, the addition of various other strategies of PTCA to thrombolytic therapy does not convincingly indicate a clinically different outcome than if a more conservative strategy is followed, in which PTCA is used only if clinically indicated. Some specific strategies, however, such as rescue PTCA in high-risk patients with occluded arteries, may be of benefit.

Acute myocardial infarction. Reperfusion strategies

Acute myocardial infarction is the result of an acute interruption of myocardial blood flow resulting in ischemic myocardial necrosis. The pathogenesis of this phenomenon nearly always involves acute thrombosis superimposed on a disrupted atherosclerotic plaque. Thrombolytic agents have been conclusively shown to reduce mortality in many patient subgroups with myocardial infarction, including the elderly, patients with inferior myocardial infarction, and patients with systolic hypertension. Nearly all patients with acute myocardial infarction of less than 6 h in duration with S-T segment elevation should receive thrombolysis unless significant contraindications exist and outweigh the potential benefits. Aspirin should be given to almost all patients regardless of whether they receive thrombolysis. Angioplasty and coronary artery bypass surgery are useful as primary or secondary modes of reperfusion in selected patients with infarction.