One-year results of the Thrombolysis in Myocardial Infarction investigation (TIMI) Phase II Trial

Natural history and prognostic implications of left ventricular end-diastolic pressure in reperfused ST-segment elevation myocardial infarction: an analysis of the thrombolysis in myocardial infarction (TIMI) II randomized controlled trial

Background

The aim of the current study is to assess the natural history and prognostic value of elevated left ventricular end-diastolic pressure (LVEDP) in patients with ST-segment elevation myocardial infarction (STEMI) after reperfusion with thrombolysis; we utilize data from the Thrombolysis in Myocardial Infarction (TIMI) II study.

Methods

A total of 3339 patients were randomized to either an invasive (n = 1681) or a conservative (n = 1658) strategy in the TIMI II study following thrombolysis. To make the current cohort as relevant as possible to modern pharmaco-invasively managed cohorts, patients in the invasive arm with TIMI flow grade ≥ 2 (N = 1201) at initial catheterization are included in the analysis. Of these, 259 patients had a second catheterization prior to hospital discharge, and these were used to define the natural history of LVEDP in reperfused STEMI.

Results

The median LVEDP for the whole cohort was 18 mmHg (IQR: 12–23). Patients were divided into quartiles by LVEDP measured during the first cardiac catheterization. During a median follow up of 3 (IQR: 2.1–3.2) years, quartile 4 (highest LVEDP) had the highest incidence of mortality and heart failure admissions. In the cohort with paired catheterization data, the LVEDP dropped slightly from 18 mmHg (1QR: 12–22) to 15 mmHg (IQR: 10–20) (p = 0.01) from the first to the pre-hospital discharge catheterization.

Conclusions

LVEDP remains largely stable during hospitalisation post-STEMI. Elevated LVEDP is a predictor of death and heart failure hospitalization in STEMI patients undergoing successful thrombolysis.

Graphic abstract

Impact of pre-angioplasty antithrombotic therapy administration on coronary reperfusion in ST-segment elevation myocardial infarction: Does time matter?

BACKGROUND

Optimal timing of antithrombotic therapy for patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PPCI) is unclear. We analyzed the impact of pre-angioplasty administration of unfractionated heparin (UFH) on infarct-related artery (IRA) patency and mortality.

METHOD

Multicenter prospective observational study of 3520 STEMI patients treated with PPCI from 2016 to 2018. Subjects were divided into four groups according to the elapsed time from heparin administration to PPCI: Group 1: Upon arrival at catheterization laboratory or ≤ 30 min (n = 800; 22.7%); Group 2: 31 to 60 min (n = 994; 28.2%); Group 3: 61 to 90 min (n = 1091; 31%); Group 4: >90 min (n = 635; 18%). IRA patency was defined as thrombolysis in myocardial infarction (TIMI) flow grade 2-3. Multivariate analyses assessed factors associated with IRA patency and both 30-day and 1-year mortality.

RESULTS

UFH administration at STEMI diagnosis was an independent predictor of IRA patency especially when administered more than 60 min before the PPCI (OR 1.43; 95% CI 1.14-1.81), either an independent predictor of 30-day (HR 0.63; 95% CI 0.42-0.94) and 1-year (HR 0.57; 95% CI 0.41-0.80) mortality. The effect of UFH on IRA patency was higher when administered earlier from the symptom onset.

CONCLUSION

UFH administration at STEMI diagnosis improves coronary reperfusion prior to PPCI and this benefit seems associated with superior clinical outcomes. The presented results highlight a time-dependent effectiveness of UFH, since its reported effect is greater the sooner UFH is administered after symptom onset.

Left ventricular remodeling after late revascularization correlates with baseline viability

The ideal management of stable patients who present late after acute ST-elevation myocardial infarction (STEMI) is still a matter of conjecture. We hypothesized that the extent of improvement in left ventricular function after successful revascularization in this subset was related to the magnitude of viability in the infarct-related artery territory. However, few studies correlate the improvement of left ventricular function with the magnitude of residual viability in patients who undergo percutaneous coronary intervention in this setting. In 68 patients who presented later than 24 hours after a confirmed first STEMI, we performed resting, nitroglycerin-enhanced, technetium-99m sestamibi single-photon emission computed tomography-myocardial perfusion imaging (SPECT-MPI) before percutaneous coronary intervention, and again 6 months afterwards. Patients whose baseline viable myocardium in the infarct-related artery territory was more than 50%, 20% to 50%, and less than 20% were divided into Groups 1, 2, and 3 (mildly, moderately, and severely reduced viability, respectively). At follow-up, there was significant improvement in end-diastolic volume, end-systolic volume, and left ventricular ejection fraction in Groups 1 and 2, but not in Group 3. We conclude that even late revascularization of the infarct-related artery yields significant improvement in left ventricular remodeling. In patients with more than 20% viable myocardium in the infarct-related artery territory, the extent of improvement in left ventricular function depends upon the amount of viable myocardium present. The SPECT-MPI can be used as a guide for choosing patients for revascularization.

Early routine percutaneous coronary intervention after fibrinolysis vs. standard therapy in ST-segment elevation myocardial infarction: a meta-analysis

AIMS

Multiple trials in patients with ST-segment elevation myocardial infarction (STEMI) compared early routine percutaneous coronary intervention (PCI) after successful fibrinolysis vs. standard therapy limiting PCI only to patients without evidence of reperfusion (rescue PCI). These trials suggest that all patients receiving fibrinolysis should receive mechanical revascularization within 24 h from initial hospitalization. However, individual trials could not demonstrate a significant reduction in 'hard' endpoints such as death and reinfarction. We performed a meta-analysis of randomized controlled trials to define the benefits of early PCI after fibrinolysis over standard therapy on clinical and safety endpoints in STEMI.

METHODS AND RESULTS

We identified seven eligible trials, enrolling a total of 2961 patients. No difference was found in the incidence of death at 30 days between the two strategies. Early PCI after successful fibrinolysis reduced the rate of reinfarction (OR: 0.55, 95% CI: 0.36-0.82; P = 0.003), the combined endpoint death/reinfarction (OR: 0.65, 95% CI: 0.49-0.88; P = 0.004) and recurrent ischaemia (OR: 0.25, 95% CI: 0.13-0.49; P < 0.001) at 30-day follow-up. These advantages were achieved without a significant increase in major bleeding (OR: 0.93, 96% CI: 0.67-1.34; P = 0.70) or stroke (OR: 0.63, 95% CI: 0.31-1.26; P = 0.21). The benefits of a routine invasive strategy over standard therapy were maintained at 6-12 months, with persistent significant reduction in the endpoints reinfarction (OR: 0.64, 95% CI: 0.40-0.98; P = 0.01) and combined death/reinfarction (OR: 0.71, 95% CI: 0.52-0.97; P = 0.03).

CONCLUSION

Early routine PCI after fibrinolysis in STEMI patients significantly reduced reinfarction and recurrent ischaemia at 1 month, with no significant increase in adverse bleeding events compared to standard therapy. Benefits of early PCI persist at 6-12 month follow-up.

Thrombolysis in Myocardial Infarction (TIMI) Risk Index predicts long-term mortality and heart failure in patients with ST-elevation myocardial infarction in the TIMI 2 clinical trial

BACKGROUND

TIMI (Thrombolysis in Myocardial Infarction) Risk Index (TRI) is a simple bedside score that predicts 30-day mortality in patients with ST-elevation myocardial infarction (MI). We sought to evaluate whether TRI was predictive of long-term mortality and clinical events.

METHODS

In the TIMI 2 trial, 3,153 patients (mean age 57 +/- 10 years, 82% men) were randomized to invasive (n = 1,583) versus conservative (n = 1,570) strategy postfibrinolysis with median follow-up of 3 years. TIMI Risk Index was divided into 5 groups. The primary end point was all-cause mortality. Secondary analyses included recurrent MI, congestive heart failure (CHF), and combined end points.

RESULTS

When compared with group 1, mortality in group 5 was more than 5-fold higher (hazard ratio [HR] 5.83, P < .0001) and was also increased in group 4 (HR 2.80, P < .0001) and group 3 (HR 1.96, P = .002) (c statistic 0.69). No difference was seen between groups 1 and 2 (P = .74). A similar increasing gradient effect was seen across TRI strata with group 5 having the highest risk for CHF (HR 4.13, P < .0001) and the highest risk for composite death/CHF (HR 4.35, P < .0001) over group 1. There was no difference in recurrent MI between the groups (P = .22). After controlling for other risk indicators, the relationship between TRI and mortality remained significant: group 5, HR 4.11, P < .0001; group 4, HR 2.14, P = .0009; group 3, HR 1.69, P = .02. When stratified by TRI groups, no differences in mortality or composite death/MI were found between treatment strategies.

CONCLUSIONS

The simple TRI can predict increased long-term mortality, CHF, and composite death/CHF.

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.

Adenosine single photon emission computed tomography for assessing risk after myocardial infarction: recent developments

PURPOSE OF REVIEW

While the prognostic power of adenosine single photon emission computed tomography myocardial perfusion imaging has been validated in multiple patient populations including those with known or suspected coronary artery disease, the utility of this modality in assessing risk after an acute myocardial infarction in the primary angioplasty era is still a topic of debate.

RECENT FINDINGS

The INSPIRE trial showed that early adenosine single photon emission computed tomography myocardial perfusion imaging is capable of identifying low-risk patients for early hospital discharge after acute myocardial infarction. This novel study demonstrated that intensive medical therapy is a reasonable strategy in low, intermediate, and high-risk post-myocardial infarction patients with preserved left ventricular function.

SUMMARY

The INSPIRE trial established the role for early adenosine single photon emission computed tomography myocardial perfusion imaging as a tool for risk stratification in stable patients after an acute myocardial infarction and provided evidence that intensive medical therapy is comparable to coronary revascularization in suppressing ischemia and presumably improving cardiac outcomes. It remains to be seen whether these new findings will alter current American College of Cardiology/American Heart Association guidelines, which emphasize a primary role of coronary revascularization in acute coronary syndromes.

An Initial Strategy of Intensive Medical Therapy Is Comparable to That of Coronary Revascularization for Suppression of Scintigraphic Ischemia in High-Risk But Stable Survivors of Acute Myocardial Infarction

OBJECTIVES

The purpose of this study was to determine the relative benefit of intensive medical therapy compared with coronary revascularization for suppressing scintigraphic ischemia.

BACKGROUND

Although medical therapies can reduce myocardial ischemia and improve patient survival after acute myocardial infarction, the relative benefit of medical therapy versus coronary revascularization for reducing ischemia is unknown.

METHODS

A prospective randomized trial in 205 stable survivors of acute myocardial infarction was made to define the relative efficacy of an intensive medical therapy strategy versus coronary revascularization for suppressing scintigraphic ischemia as assessed by serial gated adenosine Tc-99m sestamibi myocardial perfusion tomography. All patients at baseline had large total (> or =20%) and ischemic (> or =10%) adenosine-induced left ventricular perfusion defects and an ejection fraction > or =35%. Imaging was performed during 1 to 10 days of hospital admission and repeated in an identical fashion after optimization of therapy. Patients randomized to either strategy had similar baseline demographic and scintigraphic characteristics.

RESULTS

Both intensive medical therapy and coronary revascularization induced significant but comparable reductions in total (-16.2 +/- 10% vs. -17.8 +/- 12%; p = NS) and ischemic (-15 +/- 9% vs. -16.2 +/- 9%; p = NS) perfusion defect sizes. Likewise, a similar percentage of patients randomized to medical therapy versus coronary revascularization had suppression of adenosine-induced ischemia (80% vs. 81%; p = NS).

CONCLUSIONS

Sequential adenosine sestamibi myocardial perfusion tomography can effectively monitor changes in scintigraphic ischemia after anti-ischemic medical or coronary revascularization therapy. A strategy of intensive medical therapy is comparable to coronary revascularization for suppressing ischemia in stable patients after acute infarction who have preserved LV function.

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.

Percutaneous Coronary Intervention After Fibrinolysis

OBJECTIVES

We performed a meta-analysis of randomized trials that enrolled ST-segment elevation myocardial infarction patients treated with fibrinolysis to assess the potential benefits of: 1) rescue percutaneous coronary intervention (PCI) versus no PCI; 2) systematic and early (< or =24 h) PCI versus delayed or ischemia-guided PCI; 3) fibrinolysis-facilitated PCI versus primary PCI alone.

BACKGROUND

The impact of PCI strategies after fibrinolysis on mortality or reinfarction remains to be established.

METHODS

The meta-analysis was performed using the odds ratio (OR) as the parameter of efficacy with a random effect model. Fifteen randomized trials (5,253 patients) were selected. The primary end point was mortality or the combined end point of death or reinfarction.

RESULTS

Rescue PCI for failed fibrinolysis reduced mortality (6.9% vs. 10.7%) (OR, 0.63; 95% confidence interval [CI], 0.39 to 0.99; p = 0.055) and the rate of death or reinfarction (10.8% vs. 16.8%) (OR, 0.60; 95% CI, 0.41 to 0.89; p = 0.012) compared with a conservative approach. Systematic and early PCI performed during the "stent era" led to a nonsignificant reduction in mortality compared with delayed or ischemia-guided PCI (3.8% vs. 6.7%) (OR, 0.56; 95% CI, 0.29 to 1.05; p = 0.07) and to a 2-fold reduction in the rate of death or reinfarction (7.5% vs. 13.2%) (OR, 0.53; 95% CI, 0.33 to 0.83; p = 0.0067). This benefit contrasted with a nonsignificant increase in the rate of both mortality (5.5% vs. 3.9%, p = 0.33) or death or reinfarction (9.6% vs. 5.7%, p = 0.06) observed in the "balloon era." Fibrinolysis-facilitated PCI was associated with more reinfarction as compared with primary PCI alone (5.0% vs. 3.0%) (OR, 1.68; 95% CI, 1.12 to 2.51; p = 0.013) without significant impact on mortality (OR, 1.30; 95% CI, 0.92 to 1.83; p = 0.13).

CONCLUSIONS

Our findings support rescue PCI and systematic and early PCI after fibrinolysis. However, the current data do not support fibrinolysis-facilitated PCI in lieu of primary PCI alone.

Infarct zone viability influences ventricular remodelling after late recanalisation of an occluded infarct related artery

OBJECTIVE

To investigate the influence of infarct zone viability on remodelling after late recanalisation of an occluded infarct related artery.

METHODS

A subgroup of 26 volunteers from TOAT (the open artery trial) underwent dobutamine stress cardiovascular magnetic resonance at baseline to assess the amount of viable myocardium present with follow up to assess remodelling at one year. TOAT studied patients with left ventricular dysfunction after anterior myocardial infarction (MI) associated with isolated proximal occlusion of the left anterior descending coronary artery with randomisation to percutaneous coronary intervention (PCI) with stent at 3.6 weeks after MI (PCI group) or to medical treatment alone (medical group).

RESULTS

In the PCI group there was a significant relation between the number of viable segments within the infarct zone and improvement in end systolic volume index (-7.7 ml/m2, p = 0.02) and increased ejection fraction (4.1%, p = 0.03). The relation between viability and improvements in end diastolic volume index (-8.8 ml/m2, p = 0.08) and mass index (-6.3 g/m2, p = 0.01) did not reach significance (p = 0.27 and p = 0.8, respectively). In the medical group, there was no significant relation between the number of viable segments in the infarct zone and the subsequent changes in end diastolic (p = 0.84) and end systolic volume indices (p = 0.34), ejection fraction (p = 0.1), and mass index (p = 0.24).

CONCLUSION

The extent of viable myocardium in the infarct zone is related to improvements in left ventricular remodelling in patients who undergo late recanalisation of an occluded infarct related artery.

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.

Adenosine sestamibi SPECT post-infarction evaluation (INSPIRE) trial: A randomized, prospective multicenter trial evaluating the role of adenosine Tc-99m sestamibi SPECT for assessing risk and therapeutic outcomes in survivors of acute myocardial infarction

BACKGROUND

Preliminary studies indicate that adenosine myocardial perfusion single photon tomography (SPECT) can safely and accurately stratify patients into low and high risk groups early after acute myocardial infarction (AMI).

METHODS AND RESULTS

INSPIRE is a prospective, randomized multicenter trial which enrolled 728 clinically stable survivors of AMI. Following baseline adenosine sestamibi gated SPECT, patients were classified as low, intermediate or high risk based on the quantified total and ischemic left ventricular (LV) perfusion defect size (PDS). A subset of high risk patients with a LV ejection fraction > or =35% were randomized to a strategy of either intensive medical therapy or coronary revascularization. Adenosine SPECT was repeated at 6-8 weeks to determine the relative effects of anti-ischemic therapies on total and ischemic PDS (primary endpoint). All patients were followed for one year. The baseline demographic, clinical and scintigraphic characteristics of the study population are presented. Adenosine SPECT was performed within 1 day of admission in 12% of patients and in 64% by Day 4.

CONCLUSION

The unique study design features of INSPIRE will further clarify the role of adenosine sestamibi SPECT in defining initial patient risk after AMI and in monitoring the benefits of intensive anti-ischemic therapies.

Late intervention after anterior myocardial infarction: effects on left ventricular size, function, quality of life, and exercise tolerance: results of the Open Artery Trial (TOAT Study)

OBJECTIVE

We sought to conduct a randomized trial comparing late revascularization with conservative therapy in symptom-free patients after acute myocardial infarction (AMI).

BACKGROUND

In the absence of ischemia, the benefits of reperfusion late after AMI remain controversial. However, the possibility exists that an open infarct related artery benefits healing post AMI.

METHODS

Of 223 patients enrolled with Q-wave anterior AMI, 66 with isolated persistent occlusion of the left anterior descending coronary artery (LAD) were randomized to the following treatments: 1) medical therapy (closed artery group; n = 34) or 2) late intervention and stent to the LAD + medical therapy (open artery group; n = 32). The study was powered to compare left ventricular (LV) end-systolic volume between the two groups 12 months post AMI.

RESULTS

Late intervention 26 +/- 18 days post AMI resulted in significantly greater LV end-systolic and end-diastolic volumes at 12 months than medical therapy alone (106.6 +/- 37.5 ml vs. 79.7 +/- 34.4 ml, p < 0.01 and 162.0 +/- 51.4 ml vs. 130.1 +/- 46.1 ml, p < 0.01, respectively). Exercise duration and peak workload significantly increased in both groups from 6 weeks to 12 months post AMI, although absolute values were greater in the open artery group. Quality of life scores tended to deteriorate during this time interval in the closed artery patients but remained unchanged in the open artery patients. Coronary angiography at 1 year documented a low incidence of intergroup cross-over (spontaneous recanalization in 19% and closure in 11%).

CONCLUSIONS

In the present study, recanalization of occluded infarct-related arteries in symptom-free patients approximately 1 month post AMI had an adverse effect on remodeling but tended to increase exercise tolerance and improve quality of life.

Early revascularisation and 1-year survival in 14-day survivors of acute myocardial infarction: a prospective cohort study

BACKGROUND

Randomised trials of early revascularisation in acute coronary syndromes have yielded conflicting results with respect to effects on survival. We assessed the association between revascularisation within 14 days after the index event and 1-year mortality in individuals who survived for at least 14 days after an acute myocardial infarction.

METHODS

We studied a prospective cohort of patients admitted to the coronary care units of 61 Swedish hospitals between 1995 and 1998. We obtained 1-year mortality data from the Swedish National Cause of Death Register. We assessed 21,912 individuals with first registry-recorded acute myocardial infarction, who were younger than age 80 years, and alive at day 14. Relative risk of 1-year mortality in patients who had revascularisation (n=2554) or those who did not (n=19,358) within 14 days was calculated by Cox regression analysis, adjusting for multiple covariates that affect mortality and with a propensity score that adjusted for covariates that affected the likelihood of early revascularisation.

FINDINGS

At 1 year, unadjusted mortality was 9.0% (1751 deaths) in the conservative group and 3.3% (84 deaths) in the early revascularisation group. In the Cox regression analysis early revascularisation was associated with a reduction in 1-year mortality (relative risk 0.47; 95% CI 0.37-0.60; p<0.001). This relative reduction of mortality was similar in all subgroups irrespective of age, sex, baseline characteristics, previous disease manifestations, or treatment.

INTERPRETATION

Early revascularisation in individuals with acute myocardial infarction is associated with substantial reduction in 1-year mortality. Our findings lend support to the use of an invasive approach early after an acute myocardial infarction.

Critical pathways for management of patients with acute coronary syndromes: an assessment by the National Heart Attack Alert Program

BACKGROUND

The use of critical pathways for a variety of clinical conditions has grown rapidly in recent years, particularly pathways for patients with acute coronary syndromes (ACS). However, no systematic review exists regarding the value of critical pathways in this setting.

METHODS

The National Heart Attack Alert Program established a Working Group to review the utility of critical pathways on quality of care and outcomes for patients with ACS. A literature search of MEDLINE, cardiology textbooks, and cited references in any article identified was conducted regarding the use of critical pathways for patients with ACS.

RESULTS

Several areas for improving the care of patients with ACS through the application of critical pathways were identified: increasing the use of guideline-recommended medications, targeting use of cardiac procedures and other cardiac testing, and reducing the length of stay in hospitals and intensive care units. Initial studies have shown promising results in improving quality of care and reducing costs. No large studies designed to demonstrate an improvement in mortality or morbidity were identified in this literature review.

CONCLUSIONS

Critical pathways offer the potential to improve the care of patients with ACS while reducing the cost of care. Their use should improve the process and cost-effectiveness of care, but further research in this field is needed to determine whether these changes in the process of care will translate into improved clinical outcomes.

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.

Ticlopidine versus aspirin after myocardial infarction (STAMI) trial

OBJECTIVES

We sought to compare the efficacy of aspirin and ticlopidine in survivors of acute myocardial infarction (AMI) treated with thrombolysis.

BACKGROUND

The role of ticlopidine in secondary prevention after AMI has not yet been explored.

METHODS

Of 4,696 patients with AMI treated with thrombolysis who were screened, 261 died in the hospital (5.6%) and 1,470 were enrolled in this randomized, double-blind, multicenter trial and allocated to treatment with either aspirin (160 mg/day) or ticlopidine (500 mg/day). The most frequent reasons for exclusion were refusal to give informed consent, planned myocardial revascularization, risk of noncompliance with study procedures, need for anticoagulant therapy and contraindications to the study treatments. The primary end point was the first occurrence of any of the following events during the six-month follow-up: fatal and nonfatal AMI, fatal and nonfatal stroke, angina with objective evidence of myocardial ischemia, vascular death or death due to any other cause.

RESULTS

The primary end point was recorded in 59 (8.0%) of the 736 aspirin-treated and 59 (8.0%) of the 734 ticlopidine-treated patients (p = 0.966). Vascular death was the first event in five patients taking aspirin and in six patients taking ticlopidine (0.7% vs. 0.8%; p = NS); nonfatal AMI in 18 and 8 (2.4% vs. 1.1%; p = 0.049); nonfatal stroke in 3 and 4 (0.4% vs. 0.5%; p = NS); and angina in 33 and 40 (4.5% vs. 5.4%; p = NS), respectively. The frequency of adverse reactions was not significantly different between the two groups.

CONCLUSIONS

No difference was found between the ticlopidine and aspirin groups in the rate of the primary combined end point of death, recurrent AMI, stroke and angina.

Validating recommendations for coronary angiography following acute myocardial infarction in the elderly: a matched analysis using propensity scores

We determined whether adherence to recommendations for coronary angiography more than 12 h after symptom onset but prior to hospital discharge after acute myocardial infarction (AMI) resulted in better survival. Using propensity scores, we created a matched retrospective sample of 19,568 Medicare patients hospitalized with AMI during 1994-1995 in the United States. Twenty-nine percent, 36%, and 34% of patients were judged necessary, appropriate, or uncertain, respectively, for angiography while 60% of those judged necessary received the procedure during the hospitalization. The 3-year survival benefit was largest for patients rated necessary [mean survival difference (95% CI): 17.6% (15.1, 20.1)] and smallest for those rated uncertain [8.8% (6.8, 10.7)]. Angiography recommendations appear to select patients who are likely to benefit from the procedure and the consequent interventions. Because of the magnitude of the benefit and of the number of patients involved, steps should be taken to replicate these findings.

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.

A role of angiotensin-converting enzyme gene polymorphism in left ventricular remodeling after myocardial infarction

BACKGROUND

Left ventricular remodeling (LVR) process is one of the important secondary sequele after acute myocardial infarction (AMI). However, little is known about the relationship between LVR and angiotensin converting enzyme (ACE) gene polymorphism as well as endothelial nitric oxide synthase (ecNOS) gene polymorphism.

METHODS

Coronary angiography and left ventriculography were performed within 24 hours and 30+/-7 days after AMI onset. All consecutive 24 patients (57+/-6 years) had acute anterior MI with one vessel disease of left anterior descending artery and successful revascularization therapy during acute phase. Patients were divided into three groups according to the change of end-diastolic volume index (EDVI)(Delta EDVI = EDVI 1 month-EDVI within 24 hrs); LVR(+) (Delta EDVI>7.0 ml/m(2), n = 5), LVR (-)(Delta EDVI<-7.0 ml/m(2), n = 13), and LVR (+/-)(-7.0<Delta EDVI<7.0 ml/m(2), n = 6) groups. The polymorphisms of ACE and ecNOS gene were determined with PCR method after an extraction of genomic DNA from peripheral leukocytes.

RESULTS

There were no significant difference among three groups as to baseline characteristics, including coronary risk factors, medications, serum CPKmax and patency of infarct-related artery. The incidence of DD genotype of ACE gene is significantly higher in LVR (+) than in the other two groups (0.60; 0; 0, respectively, chi(2) = 13.150, p<0.01). The incidence of D allele of ACE gene is also significantly higher in LVR (+) than in the other two groups (0.70; 0.17; 0.19, respectively, chi(2) = 10.221, p<0.01). Delta EDVI of DD genotype was significantly greater than in the other two groups (DD genotype = 30.1+/-18.1; ID genotype = -13.0+/-27.4; II genotype = -8.2+/-11.5 ml/m(2), respectively, p<0.05). There was no significant difference in ecNOS gene polymorphism among three groups. By stepwise regression analysis, the significant independent predictors of Delta EDVI were EDVI within 24 hrs and DD genotype (F = 16.88 and 8.641, respectively, p = 0.0024).

CONCLUSION

These results showed that left ventricular dilatation is related to DD genotype of ACE gene after successful reperfusion therapy of anterior AMI. Thus, renin-angiotensin system may play an important role in left ventricular remodeling after AMI.

The Organization to Assess Strategies for Ischemic Syndromes (OASIS) registry in patients with unstable angina

Clinical approaches to the prevention of the potentially catastrophic consequences of coronary ischemic phenomena such as unstable angina and suspected non-Q-wave myocardial infarction (MI) differ across the world. In addition to prevailing physician beliefs in different societies, the level of access to catheterization laboratories largely determines whether an interventionist or conservative strategy is adopted. The Organization to Assess Strategies for Ischemic Syndromes (OASIS)--a prospective registry of approximately 8,000 patients with acute myocardial ischemia with no ST elevation, treated in 95 hospitals across 6 countries--furnished a unique window into regional differences in clinical management and the frequency and timing of invasive procedures (i.e., angiography, percutaneous transluminal coronary angioplasty [PTCA], and coronary artery bypass graft [CABG] surgery), as well as the outcomes of these trends. At 6 months after symptom onset, patients in the United States and Brazil, where the catheterization laboratory facilities are more accessible, underwent significantly (p <0.001) more angiography (69.4%), PTCA (23.6%), and CABG (25.2%) than in Canada and Australia, where the corresponding rates were 48.4%, 17.0%, and 16.8% (p <0.001), respectively; and in Hungary and Poland, where the respective rates were 23.5%, 5.8%, and 10.9% (p <0.001). This relatively aggressive approach led at 6 months to a more substantial decrease in refractory angina in the United States and Brazil than in Canada and Australia (20.4% vs 13.9%; p <0.001), but no improvement in rates of cardiovascular mortality and MI (10.5% versus 10.5%; p = 0.36). There was a significant (p < or = 0.012) increase in stroke, (1.9% vs 1.3%; p = 0.010) and major bleeding (1.9% vs 1.1%; p = 0.009) events. Furthermore, an inverse correlation emerged between baseline cardiovascular risk status and frequency of angiography and PTCA interventions preferentially for low-risk compared with high-risk patients. In concert with findings from other recent randomized trials, the OASIS Registry data suggest that although there are fewer hospital readmissions for unstable angina, there is a trend toward increased rates of death, MI, and stroke. These data urge a cautious approach to the use of invasive procedures in patients with unstable angina unless future trials demonstrate a clear benefit with an aggressive approach.

Long-term follow-up after direct percutaneous transluminal coronary angioplasty for acute myocardial infarction

OBJECTIVES

The purpose of this study was to analyze long-term follow-up information over several years from consecutive, unselected patients treated with direct percutaneous transluminal coronary angioplasty (PTCA) for acute myocardial infarction (MI).

BACKGROUND

Direct PTCA is often used in patients with acute MI. Short-term results are favorable. However, there is less information available on long-term observations over several years in these patients.

METHODS

A total of 416 consecutive and unselected patients with acute MI underwent direct PTCA. Survival of the acute infarct phase was 94.2%; the remaining 392 patients--the study population-were discharged and followed for 3.3+/-1.4 years. Mortality as well as cardiac events and reinterventions are reported. Clinical variables assessed at the time of discharge are submitted to statistical analysis to detect potential risk factors.

RESULTS

Total cumulative mortality in the first year was 10% for the entire group and 6% for patients not presenting in cardiogenic shock. Mortality after discharge was 4.6% in the first year and dropped to <4% per year thereafter. Reinterventions after discharge were required in 16% in the first year and in <4% per year in years 2 to 4. Poor left ventricular ejection fraction (<35%), three-vessel disease and advanced age (> or =75 years) were long-term risk factors for total mortality after direct PTCA.

CONCLUSIONS

The clinical benefit of direct PTCA for acute MI is maintained during follow-up with respect to mortality. However, reinterventions for restenosis or de novo stenosis are often required (10% to 20%). Although few in number (<10%), patients with severely impaired left ventricular function continue to have a poor prognosis.

Variations between countries in invasive cardiac procedures and outcomes in patients with suspected unstable angina or myocardial infarction without initial ST elevation. OASIS (Organisation to Assess Strategies for Ischaemic Syndromes) Registry Investigators

BACKGROUND

There are wide variations between countries in the use of invasive cardiac catheterisation and revascularisation procedures for patients with acute ischaemic syndromes. We studied the relation between rates of such procedures and rates of cardiovascular death, myocardial infarction, stroke, refractory angina, and major bleeding in a prospective, registry-based study in six countries with widely varying intervention rates.

METHODS

7987 consecutive patients presenting with unstable angina or suspected myocardial infarction without ST-segment elevation were recruited prospectively from 95 hospitals in six countries and followed up for 6 months.

FINDINGS

The rates of all procedures were highest in patients in Brazil and the USA, intermediate in Canada and Australia, and lowest in Hungary and Poland. There were no significant differences in rates of cardiovascular death or myocardial infarction among these countries (4.7% overall [range 3.7-5.6] at 7 days; 11% overall [9-12] at 6 months). For the countries with the highest rates of invasive procedures (59%) versus the rest (21%) there was no difference in rate of cardiovascular death or myocardial infarction (adjusted odds ratio 0.88 at 7 days and 1.0 at 6 months). Rates of stroke were higher in Brazil and the USA than in the countries with lower intervention rates (adjusted odds ratio at 7 days 3.0, p=0.012; at 6 months 1.8, p=0.004) but rates of refractory angina at 7 days (0.7, p<0.001) and readmission for unstable angina at 6 months were lower (0.70, 0.63; both p<0.001). Comparison of results for hospitals without cardiac-catheterisation facilities and for those with such facilities gave adjusted odds ratios for cardiovascular death, myocardial infarction, or stroke at 6 months of 0.83 (10.6% vs 12.5%, p=0.05) and for refractory angina of 1.25 (19.3% vs 16.1%, p=0.09).

INTERPRETATION

Higher rates of invasive and revascularisation procedures were associated with lower rates of refractory angina or readmission for unstable angina, no apparent reduction in cardiovascular death or myocardial infarction, but with higher rates of stroke. Randomised trials should assess the relative impact of conservative and more aggressive approaches to invasive cardiac procedures and revascularisations in patients with unstable angina.

Usefulness of technetium-99m sestamibi infarct size in predicting posthospital mortality following acute myocardial infarction

In this multicenter study, 249 patients who underwent tomographic technetium-99m sestamibi infarct size measurement at hospital discharge were followed up for a median duration of 7 months. Infarct size was significantly associated with mortality (chi-square = 5.8, p = 0.02) and could stratify patients into lower and higher risk subsets: 1-year mortality 2% for infarct size < 14% versus 8% for infarct size > or = 14% of the left ventricle.

Assessing myocardial perfusion in coronary artery disease with magnetic resonance first-pass imaging

MRFP perfusion imaging can now be used clinically on most MR scanner systems (1.0 to 1.5 T). The current experimental data demonstrate that MRFP imaging allows the quantitative assessment of myocardial blood flow changes and accurate measurements of collateral flow, including changes in the collateral dependent zones. Certain protocols, however, as outlined here have to be followed to obtain all the possible diagnostic information. Based on the current data on MRFP imaging, it is realistic to anticipate that MRFP imaging in combination with cine or tagging MR imaging will provide clinicians with better methods to distinguish stunned and hibernating, from nonviable myocardium and obtain better outcome data. Dedicated MR scanners are now being designed to meet the needs for MR imaging of patients with coronary artery disease. These scanners, small in size and with better patient access, make placement near the coronary care unit or catheterization laboratory feasible. This is a major step toward enhancing the utility of this new technique by providing the necessary infrastructure for scanning large numbers of patients. The main obstacle to wider use of these new diagnostic tools to assess perfusion is the lack of a large clinical database because there have not yet been major multicenter trials. With the development of novel intravascular contrast agents, however, larger trials are planned that should provide the clinical data mandatory for full integration of MRFP imaging into clinical practice. In particular, the development of dedicated and user-friendly perfusion analysis software will create the means to evaluate MR perfusion data accurately in large patient populations. These studies need to be conducted in a collaborative fashion by cardiologists, heart surgeons, and radiologists to be fully accepted by health care providers in an increasingly cost-averse and competitive health care environment.

Effect of infarct-related artery patency and late potentials on late mortality after acute myocardial infarction

OBJECTIVE

To assess the effect of patency of the infarct-related artery and the presence of late potentials on late cardiac mortality after myocardial infarction.

MATERIAL AND METHODS

We studied the influence of the infarct-related artery patency and the presence of late potentials during signal-averaged electrocardiography on late mortality in 124 survivors of acute myocardial infarction. In addition, we assessed predictive factors of cardiac mortality by univariate and multivariate statistical analysis.

RESULTS

A study group of 98 men and 26 women (mean age, 59 years) who were survivors of acute myocardial infarction underwent follow-up for a mean of 3.6 +/- 1.0 years. Immediate reperfusion therapy (thrombolysis or direct angioplasty) was accomplished in 71 patients (57%). During follow-up, 13 cardiac-associated deaths occurred. Infarct-related artery patency was strongly associated with improved survival, but the presence of late potentials did not correlate with increased mortality, even among patients with impaired left ventricular function. Univariate and multivariate analyses identified occluded infarct-related arteries, prior myocardial infarction, reduced left ventricular ejection fraction, and advanced age, but not late potentials, as predictors of increased late cardiac mortality.

CONCLUSION

These data suggest that coronary angiography may, but signal-averaged electrocardiography may not, identify patients with increased late risk of cardiac-related death after myocardial infarction. The low mortality among patients who have undergone successful reperfusion therapy may reduce the ability of noninvasive tests to distinguish between high- and low-risk patients.

A composite view of cardiac rupture in the United States National Registry of Myocardial Infarction

OBJECTIVES

This study was done to determine the incidence, timing and prevalence as a cause of death from cardiac rupture in patients with acute myocardial infarction.

BACKGROUND

Several clinical trials and overview analyses have suggested that the survival benefit conferred by thrombolytic therapy may be offset by a paradoxic increase in early deaths from cardiac rupture.

METHODS

Demographic, procedural and outcome data from patients with acute myocardial infarction were collected at 1,073 United States hospitals collaborating in the United States National Registry of Myocardial Infarction.

RESULTS

Among the 350,755 patients enrolled, 122,243 received thrombolytic therapy. In-hospital mortality for the overall patient population, those not treated with thrombolytics (n = 228,512) and those given thrombolytics were 10.4%, 12.9% and 5.9%, respectively (p<0.001). Cardiogenic shock was the most common cause of death in each patient group. Although the incidence of cardiac rupture was low (<1.0%), it was responsible for 7.3%, 6.1% and 12.1%, respectively, of in-hospital deaths (p<0.001). Death from rupture occurred earlier in patients given thrombolytic therapy, with a clustering of events within 24 h of drug administration. Despite the early risk, death rates were comparatively low in thrombolytic-treated patients on each of the first 30 days. By multivariable analysis, thrombolytics, prior myocardial infarction, advancing age, female gender and intravenous beta-blocker use were independently associated with cardiac rupture.

CONCLUSIONS

This large registry experience, including over 350,000 patients with myocardial infarction, suggests that thrombolytic therapy accelerates cardiac rupture, typically to within 24 to 48 h of treatment. The possibility that rupture represents an early hemorrhagic complication of thrombolytic therapy should be investigated.

Decline in the rate of hospital mortality from acute myocardial infarction: impact of changing management strategies

This study examined the profile and management of acute myocardial infarction in patients hospitalized in the coronary care unit of Henry Ford Hospital to determine risk factors or treatments that best explained a decline in in-hospital mortality rates. During the 1980s and early 1990s, many therapeutic advances occurred in management of acute infarction. Overall and in-hospital mortality were observed also to decline, but little is known about the relation of newer treatments to clinical outcome. The study population consisted of 1798 patients with a confirmed diagnosis of myocardial infarction. Of these, 982 consecutive patients were hospitalized in the coronary care unit of Henry Ford Hospital from January 1981 through December 1984 and compared with the 816 consecutive patients hospitalized from January 1990 through October 1992. Data on baseline demographics, initial clinical features, in-hospital management, and in-hospital outcome were compared for the two groups. Logistic regression was used to define independent predictors of the improved outcome of the two groups. Demographic features of the earlier group were similar to those of the later cohort, with the exception of a greater incidence of diabetes and hypertension and a lesser incidence of angina and prior heart failure. The occurrence of non-Q wave infarction increased from 27% in the earlier to 39% in the later group, whereas the magnitude of peak creatine kinase elevation in serum was higher in the later group. Medical management differed significantly, with increased use of aspirin, thrombolytics, heparin, warfarin, nitrates, and beta-blockers and decreased use of antiarrhythmic agents, digoxin, and vasopressors in the later group. Coronary revascularization was performed during hospitalization in 6.4% of the earlier group of patients and 31.6% of the later group. In-hospital mortality was 14.7% in the earlier group and 7.4% in the later group. Multivariate logistic regression analysis showed that the difference in mortality between the two groups was best accounted for by increased use of beta-blockers, angioplasty, and thrombolytics, decreased incidence of cardiogenic shock and asystole, and decreased use of lidocaine. In conclusion, the presentation and in-hospital management of patients with acute myocardial infarction has changed from the early 1980s to the early 1990s. The improved hospital mortality rate may be associated with both the expanded use of effective therapies and a more favorable in-hospital course, although these are not mutually exclusive.