Comparison of immediate invasive, delayed invasive, and conservative strategies after tissue-type plasminogen activator. Results of the Thrombolysis in Myocardial Infarction (TIMI) Phase II-A trial

Creatine kinase is associated with bleeding after myocardial infarction

BACKGROUND

The ADP-scavenging enzyme creatine kinase (CK) is reported to reduce ADP-dependent platelet activation. Therefore, we studied whether highly elevated CK after ST-elevation myocardial infarction (STEMI) is associated with bleeding.

METHODS

Data of the Thrombolysis in Myocardial Infarction Study Group phase II trial on the efficacy of angioplasty, following intravenous recombinant tissue-type plasminogen activator (rt-PA), are used to assess whether peak plasma CK (CKmax) is independently associated with adjudicated fatal or non-fatal bleeding (primary) and combined bleeding/all-cause mortality (secondary) in multivariable binomial logistic regression analysis, adjusting for baseline and treatment allocation covariates.

RESULTS

The included patients (n=3339, 82% men, 88% white, mean age 57 years, SE 0.2) had a history of angina pectoris (55%), hypertension (38%) and/or diabetes mellitus (13%). CKmax ranged from 16 to 55 890 IU/L (mean 2389 IU/L, SE 41), reached within 8 hours in 51% of the patients (93% within 24 hours). Adjudicated fatal/non-fatal bleeding occurred in 30% of the patients (respectively 26% in the low vs 34% in the high CK tertile), and bleeding/all-cause mortality in 35% (29% in the low vs 40% in the high CK tertile). In multivariable regression analysis, the adjusted OR for fatal/non-fatal bleeding (vs not bleeding and survival) was 2.6 (95% CI 1.8 to 3.7)/log CKmax increase, and 3.1 (2.2 to 4.4) for bleeding/all-cause mortality.

CONCLUSION

Highly elevated plasma CK after myocardial infarction might be an independent predictor of bleeding and haemorrhagic death. This biologically plausible association warrants further prospective study of the potential role of extracellular CK in ADP-dependent platelet activation and bleeding.

Current Perspectives in Facilitated Angioplasty

BACKGROUND

Ischemic heart disease represents the most important cause of mortality worldwide, and the management of patients with ST-elevation myocardial infarction (STEMI) still remains a great challenge. For a great number of patients who do not have immediate access to primary percutaneous coronary intervention (PCI), facilitated angioplasty may be a reasonable therapeutic option.

AREAS OF UNCERTAINTY

The goal of reperfusion therapy is achieving repermeabilization of the infarct-related artery. However, the restoration of normal epicardial flow is not always followed by microvascular tissue perfusion and the presence of myocardial blush. Early studies assessing the benefits of facilitated angioplasty over primary PCI encountered disappointing results, with an increased number of bleeding complications. The invasive strategy following fibrinolysis mainly consists in angiography and PCI of the infarct-related artery between 2 and 24 hours after successful fibrinolysis or rescue PCI in failed fibrinolysis, hemodynamic, electrical instability, or worsening ischemia. Currently, a strategy of routine early angiography after fibrinolysis is recommended, taking into account studies that have demonstrated a reduced rate of reinfarction and recurrent ischemia, without an increased risk of stroke or major bleeding complications.

THERAPEUTIC ADVANCES

After evaluating 1892 patients with STEMI within 3 hours after the onset of symptoms and revealing, beyond clear benefit of fibrinolysis, an increased risk of bleeding complications, the STREAM trial was the one that led to halving the tenecteplase dose for patients aged >75 years. A safety profile of adjusted-dose fibrinolytic therapy in elderly patients with STEMI will be further investigated by the ongoing STREAM-2 trial.

CONCLUSIONS

With the current increased burden of acute coronary syndromes and the lack of immediate primary PCI facilities for all patients with STEMI, facilitated angioplasty seems a feasible therapeutic option. Another benefit of facilitated angioplasty may be represented by a major contribution of thrombolytic therapy in re-establishing microvascular myocardial blood flow.

Therapeutic Fibrinolysis: How Efficacy and Safety Can Be Improved

Therapeutic fibrinolysis has been dominated by the experience with tissue-type plasminogen activator (t-PA), which proved little better than streptokinase in acute myocardial infarction. In contrast, endogenous fibrinolysis, using one-thousandth of the t-PA concentration, is regularly lysing fibrin and induced Thrombolysis In Myocardial Infarction flow grade 3 patency in 15% of patients with acute myocardial infarction. This efficacy is due to the effects of t-PA and urokinase plasminogen activator (uPA). They are complementary in fibrinolysis so that in combination, their effect is synergistic. Lysis of intact fibrin is initiated by t-PA, and uPA activates the remaining plasminogens. Knockout of the uPA gene, but not the t-PA gene, inhibited fibrinolysis. In the clinic, a minibolus of t-PA followed by an infusion of uPA was administered to 101 patients with acute myocardial infarction; superior infarct artery patency, no reocclusions, and 1% mortality resulted. Endogenous fibrinolysis may provide a paradigm that is relevant for therapeutic fibrinolysis.

Controversies in the Treatment of Women with ST-Segment Elevation Myocardial Infarction

Coronary artery disease is the leading cause of death in women. Women with ST-segment elevation myocardial infarctions continue to have worse outcomes compared with men despite advancements in therapies. Furthermore, these differences are particularly pronounced among young men and women with myocardial infarctions. Differences in the pathophysiology of coronary artery plaque development, disease presentation, and recognition likely contribute to these outcome disparities. Despite having worse outcomes compared with men, women clearly benefit from aggressive treatment and the latest therapies. This article reviews the treatment options for ST-segment elevation myocardial infarctions and the outcomes of women after treatment with reperfusion therapies.

Risks and Benefits of Thrombolytic, Antiplatelet, and Anticoagulant Therapies for ST Segment Elevation Myocardial Infarction: Systematic Review

Objectives. Assess the impact of associating thrombolytics, anticoagulants, antiplatelets, and primary angioplasty (PA) on death, reinfarction (AMI), and major bleeding (MB) in STEMI therapy. Methods. Medline search was performed to identify randomized trials comparing these classes in STEMI treatment, at least 500 patients, providing death, AMI, and MB rates. Similar arms were grouped. Correlation between number of drugs and PA and the outcomes was evaluated, as well as correlation between the year of the study and the outcomes. Results. Fifty-nine papers remained after exclusions. 404.556 patients were divided into 35 groups of arms. There was correlation between the number of drugs and rates of death (r = -0.466, P = 0.005) and MB (r = 0.403, P = 0.016), confirmed by multivariate regression. This model also showed that PA is associated with lower mortality and increased MB. Year and period of publication correlated with the outcomes: death (r = -0.380, P < 0.001), MB (r = 0.212, P = 0.014), and AMI (r = -0.231, P = 0.009). Conclusion. The increasing complexity of STEMI treatment has resulted in significant reduction in mortality along with increased rates of MB. Overall, however, the benefits of treatment outweigh the associated risks of MB.

Efficacy and safety of a routine early invasive strategy after fibrinolysis stratified by glycoprotein IIb/IIIa inhibitor use during percutaneous coronary intervention: a pre-specified subgroup analysis of the TRANSFER-AMI randomised controlled trial

OBJECTIVE

We evaluated the efficacy and safety of an early invasive strategy post-fibrinolysis in relation to glycoprotein (GP) IIb/IIIa inhibitor use.

METHODS

The Trial of Routine Angioplasty and Stenting after Fibrinolysis to Enhance Reperfusion in Acute Myocardial Infarction (TRANSFER-AMI) randomised 1059 ST elevation myocardial infarction patients to an early invasive strategy or standard therapy post-fibrinolysis. The primary end point was the composite of death, reinfarction, recurrent ischaemia, new or worsening heart failure, or cardiogenic shock at 30 days. In this pre-specified analysis, we examined efficacy and safety outcomes of an early invasive strategy after stratification by GPIIb/IIIa inhibitor use, which was permitted during percutaneous coronary intervention (PCI) at the discretion of the treating physician.

RESULTS

A total of 695 patients (65.6%) received GPIIb/IIIa inhibitors. There was significant heterogeneity (p<0.001) in the efficacy of an early invasive strategy compared to standard therapy, between the strata with GPIIb/IIIa inhibitor use (primary end point 9.6% vs 22.3% respectively, p<0.001) and without GPIIb/IIIa inhibitor use (primary end point 14.8% vs 10.4% respectively, p=0.21). Patients who received GPIIb/IIIa inhibitors had lower Global Registry of Acute Coronary Events (GRACE) risk scores compared to those without GPIIb/IIIa inhibitor use (median 121 vs 130, p<0.001). After adjusting for the interaction between GRACE risk score and treatment assignment, the heterogeneity in the efficacy of an early invasive strategy with respect to GPIIb/IIIa inhibitor use was no longer significant (p interaction=0.08).

CONCLUSIONS

The apparent difference in the efficacy of an early invasive strategy between GPIIb/IIIa inhibitor strata likely reflects an association between GPIIb/IIIa inhibitor use and baseline risk. GPIIb/IIIa inhibitor use during PCI at the discretion of the treating physician does not appear to modulate the efficacy of an early invasive strategy post-fibrinolysis.

CLINICAL TRIAL REGISTRATION

http://www.clinicaltrials.gov/ct2/show/NCT00164190, NCT00164190.

Interventions for ST Elevation Myocardial Infarction in Women

The management of ST-segment elevation myocardial infarction (STEMI) has significantly advanced from supportive care to reperfusion therapies with thrombolytics and percutaneous coronary revascularization techniques. These advances have improved the outcomes of patients with STEMI. Although cardiovascular disease is the leading cause of death in both men and women, the minority of patients in trials studying the impact of these therapies on outcomes are women. Multiple studies have shown that men and women do not have equivalent outcomes after STEMI. This article reviews the treatment options for STEMI and the outcomes of women after treatment with reperfusion therapies.

Effectiveness and safety of percutaneous coronary intervention after fibrinolytic therapy for ST-segment elevation acute myocardial infarction

The goal of treatment of an acute ST-segment elevation myocardial infarction is the timely restoration of myocardial blood flow to decrease myocardial necrosis and thereby preserve cardiac tissue and overall function. Mainstays of reperfusion treatment include fibrinolytic therapy and/or primary percutaneous coronary intervention. In those patients who are treated with fibrinolysis, there is debate as to whether and when they should also undergo subsequent percutaneous coronary intervention. In conclusion, the investigators review the published reports on systematic percutaneous coronary intervention after fibrinolytic therapy in the treatment of ST-segment elevation myocardial infarction and discuss the rationale behind this treatment strategy.

Early percutaneous coronary intervention after fibrinolysis for acute ST elevation myocardial infarction: results of two German multi‐centre registries (ACOS and GOAL)

OBJECTIVES

We evaluated the outcome of early percutaneous coronary intervention (PCI) after fibrinolysis in patients presenting with ST elevation myocardial infarction (STEMI) in clinical practice.

RESULTS

2230 consecutive patients with STEMI treated with fibrinolysis were divided into two groups: patients treated with fibrinolysis only (n = 1540) or with additional PCI (n = 690) within a median of 150 min. In-hospital mortality (9.3% versus 5.9%) and death/myocardial re-infarction (13.9% versus 9.7%) occurred significantly less often in the PCI group. After adjustment for the confounding factors in the propensity score analysis PCI did not significantly affect hospital mortality (OR 0.88, 95% CI 0.57-1.36) and death/myocardial re-infarction (OR 0.86, 95% CI 0.61-1.20) in the overall patients collective. Major bleeding complications were observed more often in the PCI group (7.3% versus 4.2%). In patients with a higher risk profile (TIMI risk score > or = 5) (n = 494) PCI was associated with a significant reduction of hospital mortality (OR 0.40, 95% CI 0.20-0.78) and death/myocardial re-infarction (OR 0.36, 95 % CI 0.19-0.67).

CONCLUSIONS

In the overall patients' collective early PCI after fibrinolysis is not associated with an improved clinical outcome. However, in patients with a higher risk profile an early invasive strategy is associated with a risk reduction for mortality and the combined endpoint of death/myocardial re-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.

Myocardial protection via the coronary sinus

BACKGROUND

Recent reports on facilitated reperfusion therapy re-address interests in coronary sinus interventions (CSI). Patients in whom short time results have been reported earlier were re-evaluated, with the aim of gathering the long-term results of pressure-controlled intermittent coronary sinus occlusion (PICSO) generated in patients with acute myocardial infarction (MI) and revascularization.

METHODS AND RESULTS

Thirty-four patients with ST elevated MI, in whom complete revascularization was achieved, underwent primary thrombolysis with or without PICSO. Follow-up data from these patients were collected for at least 48 months. Immediate perioperative differences were observed for time to peak creatine kinase (CK), as well as cumulative CK. In addition, the time until reperfusion was considerably less than for the control group (p=0.014). Long-term data showed significant differences in reinfarction (p=0.015), as well as in major adverse cardiovascular events, between the 2 groups (p<0.0001).

CONCLUSION

These data, because of the wide interval between collection and current analysis, could have inherited historical bias. Nonetheless, they are also uniquely indicating the potential of CSI to induce not only immediate, but also clinically significant long-term, effects as an adjunct to reperfusion therapy. Therefore, CSI should be, once again, on the study agenda and be placed under contemporary and best-available scientific scrutiny.

Contemporary outcomes of rescue percutaneous coronary intervention for acute myocardial infarction: comparison with primary angioplasty and the role of distal protection devices (EMERALD trial)

BACKGROUND

The value of distal protection devices during rescue PCI has not been studied.

METHODS

The population enrolled in a prospective, randomized multicenter trial of distal microcirculatory protection in ST-elevation MI, was stratified for those undergoing rescue (n = 93) or primary (n = 408) PCI; we performed the prespecified comparisons of distal protection in rescue and primary PCI.

RESULTS

Compared to primary PCI, rescue patients had higher baseline rates of TIMI-3 flow, but lower rates of post PCI TIMI-3 flow. However, no differences in the primary endpoints of complete ST-segment resolution (STR) at 30 minutes or infarct size, or 6 month mortality were present. In rescue PCI patients, randomization to distal protection did not significantly affect infarct size, STR, mortality or other clinical events.

CONCLUSION

Despite reduced rates of post-procedural TIMI-3 flow, patients undergoing rescue PCI compared to primary PCI have similar myocardial perfusion, infarct size and clinical outcomes. Distal protection did not offer any detectable benefit in this patient population.

Surgery for myocardial salvage in acute myocardial infarction and acute coronary syndromes

This article addresses the pathophysiology, the treatment options, and their rationale in the setting of life-threatening acute myocardial infarction and acute on chronic ischemia. Although biases may exist between cardiologists and surgeons, with this review, we hope to provide the reader with information that will shed light on the options that best suit the individual patient in a given set of circumstances.

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.

[Acute myocardial infarction: what is new?]

Current recommendations on the management of acute myocardial infarction and the use of thrombolysis are reviewed.

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.

Immediate angioplasty after thrombolysis: a systematic review

BACKGROUND

The role of immediate transfer for percutaneous coronary intervention (PCI) after thrombolysis for ST-segment elevation myocardial infarction remains controversial. We performed a systematic review of the related literature to determine whether thrombolysis followed by transfer for immediate or early PCI is safe, feasible and superior to conservative management.

METHODS

A systematic literature search of MEDLINE, EMBASE, the Cochrane Database for Systematic Reviews and Cochrane Central Register of Controlled Trials, and the American Heart Association EndNote 7 Master Library databases, was performed to 2004 for relevant published studies. The level of evidence and the quality of the study design and methods were rated by 2 reviewers according to a standardized classification. A quantitative meta-analysis was performed to assess the effect at 6-12 months on mortality of immediate or early PCI after thrombolysis.

RESULTS

We found 13 articles that were supportive of immediate or early PCI after thrombolysis and 16 that were neutral or provided evidence opposing it. The largest randomized trials and meta-analyses showed no benefit of routine PCI immediately or shortly after thrombolysis. The studies that were supportive were generally more recent and more frequently involved coronary stents. One large trial supported early PCI after thrombolysis for patients with myocardial infarction complicated by cardiogenic shock. Overall, the difference in mortality rates between the invasive strategy and conservative care was nonsignificant. The 3 stent-era trials showed a significantly lower mortality among patients randomly assigned to the invasive strategy (5.8% v. 10.0%, odds ratio 0.55, 95% confidence interval 0.32-0.92). Analysis of variance found a significant difference in treatment effect between stent-era and pre-stent-era trials.

INTERPRETATION

At present, there is inadequate evidence to recommend routine transfer of patients for immediate or early PCI after successful thrombolysis. Results of recent trials using contemporary PCI techniques, including coronary stents, appear more favourable but need to be confirmed in large randomized trials, which are currently in progress. Transfer for immediate PCI is recommended for patients with cardiogenic shock, hemodynamic instability or persistent ischemic symptoms after thrombolysis.

Combined Angioplasty and Pharmacological Intervention Versus Thrombolysis Alone in Acute Myocardial Infarction (CAPITAL AMI Study)

OBJECTIVES

We compared a strategy of tenecteplase (TNK)-facilitated angioplasty with one of TNK alone in patients presenting with high-risk ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

Previous trials show that thrombolysis followed by immediate angioplasty for the treatment of STEMI does not improve ischemic outcomes compared with thrombolysis alone and is associated with excessive bleeding complications. Since the publication of these trials, however, significant pharmacological and technological advances have occurred.

METHODS

We randomized 170 patients with high-risk STEMI to treatment with TNK alone (84 patients) or TNK-facilitated angioplasty (86 patients). The primary end point was a composite of death, reinfarction, recurrent unstable ischemia, or stroke at six months.

RESULTS

At six months, the incidence of the primary end point was 24.4% in the TNK-alone group versus 11.6% in the TNK-facilitated angioplasty group (p = 0.04). This difference was driven by a reduction in the rate of recurrent unstable ischemia (20.7% vs. 8.1%, p = 0.03). There was a trend toward a lower reinfarction rate with TNK-facilitated angioplasty (14.6% vs. 5.8%, p = 0.07). No significant differences were observed in the rates of death or stroke. Major bleeding was observed in 7.1% of the TNK-alone group and in 8.1% of the TNK-facilitated angioplasty group (p = 1.00).

CONCLUSIONS

In patients presenting with high-risk STEMI, TNK plus immediate angioplasty reduced the risk of recurrent ischemic events compared with TNK alone and was not associated with an increase in major bleeding complications.

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.

Early and long-term outcome of elective stenting of the infarct-related artery in patients with viability in the infarct-area: Rationale and design of the Viability-guided Angioplasty after acute Myocardial Infarction-trial (The VIAMI-trial)

Background

Although percutaneous coronary intervention (PCI) is becoming the standard therapy in ST-segment elevation myocardial infarction (STEMI), to date most patients, even in developed countries, are reperfused with intravenous thrombolysis or do not receive a reperfusion therapy at all. In the post-lysis period these patients are at high risk for recurrent ischemic events. Early identification of these patients is mandatory as this subgroup could possibly benefit from an angioplasty of the infarct-related artery.

Since viability seems to be related to ischemic adverse events, we initiated a clinical trial to investigate the benefits of PCI with stenting of the infarct-related artery in patients with viability detected early after acute myocardial infarction.

Methods

The VIAMI-study is designed as a prospective, multicenter, randomized, controlled clinical trial. Patients who are hospitalized with an acute myocardial infarction and who did not have primary or rescue PCI, undergo viability testing by low-dose dobutamine echocardiography (LDDE) within 3 days of admission. Consequently, patients with demonstrated viability are randomized to an invasive or conservative strategy. In the invasive strategy patients undergo coronary angiography with the intention to perform PCI with stenting of the infarct-related coronary artery and concomitant use of abciximab. In the conservative group an ischemia-guided approach is adopted (standard optimal care).

The primary end point is the composite of death from any cause, reinfarction and unstable angina during a follow-up period of three years.

Conclusion

The primary objective of the VIAMI-trial is to demonstrate that angioplasty of the infarct-related coronary artery with stenting and concomitant use of abciximab results in a clinically important risk reduction of future cardiac events in patients with viability in the infarct-area, detected early after myocardial infarction.

Stress radionuclide myocardial perfusion imaging detects more residual ischemia than stress echocardiography following acute myocardial infarction

OBJECTIVES

This investigation sought to compare the abilities of stress radionuclide myocardial perfusion imaging and stress echocardiography to detect residual ischemia in patients following acute myocardial infarction (MI).

BACKGROUND

Stress radionuclide myocardial perfusion imaging and stress echocardiography are both commonly used to assess patients (patients.) in the immediate post MI period. However, the relative value of these techniques in identifying post MI ischemia remains unclear.

METHODS

Eighteen patients. underwent both dipyridamole radionuclide perfusion imaging and dobutamine stress echocardiography on the same day or on consecutive days, 3-7 days following uncomplicated acute MI. Pts. who had an acute percutaneous intervention were excluded. Images were reviewed with clinical information available, but blinded to the opposing modality, for perfusion defects, wall motion abnormalities (WMA), and evidence of ischemia (reversible defect(s) on perfusion imaging, worsening WMA on stress echocardiography). Of the 18 patients, 11 subsequently underwent cardiac catheterization.

RESULTS

Perfusion imaging identified defects in 16 (89%) patients, of whom 15 (83% of total) were found to be ischemic. Stress echocardiography identified a fixed wall motion abnormality in 17 (94%) and ischemia in 8 (44%, p < 0.05 compared with perfusion imaging ischemia). Among 11 patients who underwent catheterization, there was a trend towards perfusion imaging identifying more ischemia in the territory of an obstructed (> or = 70%) vessel--100% (11/11) vs. 64% (7/11) for stress echocardiography (p = 0.09).

CONCLUSION

In the immediate post-infarction period, dipyridamole stress radionuclide myocardial perfusion imaging more often shows evidence of residual ischemia than dobutamine stress echocardiography.

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.

Synergistic treatment of ST-segment elevation myocardial infarction with pharmacoinvasive recanalization

Both pharmacologic and mechanical approaches designed to limit infarct size by recanalization of infarct-related arteries have reduced mortality associated with ST-segment elevation myocardial infarction (STEMI). Early efforts to combine the two were attenuated because of complications encountered. Primary percutaneous coronary intervention (PCI) and thrombolysis became viewed as alternative rather than complementary modalities. Time to recanalization and adequacy of restoration of perfusion were found to be pivotal determinants of a favorable outcome with either approach. Because pharmacologic intervention can be initiated immediately in virtually any hospital, it is a promising initial step. Because PCI proffers more complete recanalization, it may be a particularly salutary initial or subsequent step. Because of unavoidable delay often confronting implementation of PCI, optimal advantage may accrue from the use of both approaches in combination. We seek to emphasize the potential synergy by referring to the combined approach as "pharmacoinvasive recanalization" rather than by the conventional term "facilitated PCI." Virtually all patients with STEMI can benefit from prompt, sustained, and complete coronary recanalization. Thus, investigations focusing on identification of pharmacologic regimens that can safely initiate recanalization as early as possible, minimize bleeding, and broaden the temporal window available for efficacy of subsequent, optimally timed PCI should provide particularly valuable information.

Outcomes of primary coronary angioplasty and angioplasty after initial thrombolysis in the treatment of 374 consecutive patients with acute myocardial infarction

BACKGROUND

In patients with acute myocardial infarction (MI), the efficacy of thrombolysis is low. Angioplasty after failed thrombolysis (rescue percutaneous coronary angioplasty [PTCA]) has been associated with an increase in the incidence of inhospital complications. It has been proposed that these complications result from the procedure itself. Thus, the aim of this study was to compare the efficacy, inhospital complications, and mortality rate of patients with MI who are treated with primary PTCA and PTCA after initial thrombolysis (rescue or immediate rescue) in an experienced clinical center specializing in percutaneous coronary interventions.

METHODS AND RESULTS

The study group consisted of consecutive patients with MI treated with primary PTCA (n = 195) or PTCA after initial thrombolysis (n = 179). The study was performed in a referral center with a 24-hour catheter-laboratory service. The success rate of the procedure was 90.5% and 88.2% in the PTCA after initial thrombolysis group and primary PTCA group, respectively. The groups did not differ in the frequency of reocclusion, emergency surgical revascularization (coronary artery bypass grafting), or stroke. In patients without cardiogenic shock, the inhospital mortality rates were 3.2% and 0.6% in the rescue and immediate rescue group and primary PTCA group, respectively (not significant). In a subgroup of patients with cardiogenic shock, the mortality rate was 36.0% in the initial thrombolysis PTCA group and 30.8% in the primary PTCA group. However, after successful PTCA in this subgroup, the mortality rate dropped to 18% and 10%, respectively.

CONCLUSIONS

After initial thrombolysis, PTCA is safe, effective, and likely to restore grade 3 Thrombolysis In Myocardial Infarction flow in about 90% of patients. When available, immediate rescue PTCA should be performed in all patients, including patients with cardiogenic shock.

Stent implantation in acute myocardial infarction using a heparin-coated stent: a pilot study as a preamble to a randomized trial comparing balloon angioplasty and stenting

Preliminary experience with primary stenting in myocardial infarction has suggested a greater benefit in clinical outcome than has been obtained with direct balloon angioplasty. However, subacute thrombosis (SAT) remains a limitation for this new mode of therapy. In the BENESTENT II Pilot and main trials, the incidence of SAT with the heparin-coated Palmaz-Schatz stent was only 0.15%. Therefore, as a preamble to a large randomized trial, the feasibility and safety of the use of the Heparin-Coated Palmaz-Schatz trade mark Stent in Acute Myocardial Infarction (AMI) was tested in 101 patients enrolled between April and September 1996 in 18 clinical centres. In 101 stent-eligible AMI patients, as dictated by protocol, a heparin-coated stent was implanted. The primary objectives were to determine the in-hospital incidence of major adverse cardiac events (MACE: death, MI, target lesion revascularization) and bleeding complications, while the secondary objectives were the procedural success rate and the MACE, the restenosis and reocclusion rates at 6.5 months. Stent implantation (n 3 129 stents) was successful in 97 patients of the 101 who were included in this trial. During their hospital stay, two patients died and no patient experienced re-infarction, ischaemia prompting re-PTCA or CABG. Four patients suffered a bleeding complication, three major and one minor, of whom three required surgical repair. At 210 days follow-up, 81% of the patients were event free. At 6.5 months restenosis was documented in 18% of the 88 patients who underwent follow-up angiography, including three total occlusions. The results, both with respect to QCA and the occurrence of MACE, compare favourably with studies using elective stenting in both stable and unstable angina patients. As a result of this pilot study, a large randomized trial comparing direct balloon angioplasty with direct stenting in 900 patients with AMI was initiated in December 1996.

Continuous vectorcardiography is superior to standard electrocardiography in the prediction of long-term outcome after thrombolysis in patients with acute myocardial infarction

BACKGROUND

Thrombolytic therapy results in reperfusion of the occluded coronary vessel in approximately 75% of treated patients with acute myocardial infarction (AMI). Unsuccessful thrombolysis results in impaired outcome. This study was undertaken to evaluate reperfusion assessments with 12-lead standard static electrocardiography (ECG) and continuous vectorcardiography (VCG) in AMI patients treated with thrombolytic therapy, with particular emphasis on the value of these assessments in relation to long-term outcome.

METHODS

ST-recovery analysis 90 and 180 min after the start of thrombolytic therapy was performed by repeated ECG and by VCG in 63 AMI patients. Median follow-up was 255 days.

RESULTS

No significant differences in long-term outcome were found between patients with or without obtained reperfusion, as assessed by ECG. For VCG, we found significant elevated relative risks for experiencing death (relative risk = 11.00, confidence interval = 2.70-44.90); P = 0.0008 for the group with ST-vector magnitude recovery of less than 50% at 90 min from start of thrombolytic therapy.

CONCLUSION

We demonstrated that early reperfusion assessment with VCG enables the prediction of long-term outcome and is superior to reperfusion assessment with standard static ECG in this regard. We therefore recommend continuous ischemia monitoring of AMI patients treated with thrombolytic therapy as a routine procedure.

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.

Failed reperfusion after thrombolytic therapy: recognition and management

BACKGROUND

Failed reperfusion after thrombolysis occurs in as many as 30% of patients with acute myocardial infarction (MI). Furthermore, some patients have incomplete tissue perfusion despite reperfusion of the infarct-related artery. Close assessment of the efficacy of thrombolytic administration in people with evolving acute MI is necessary, particularly with regard to myocardial perfusion status, because some patients may benefit from incremental pharmacologic or invasive reperfusion strategies.

PURPOSE AND METHOD

This article reviews a number of strategies to assess infarct-related artery patency and myocardial tissue perfusion. These include coronary angiography, continuous ST-segment monitoring, serial electrocardiography, obtaining serial serum biochemical markers of myocardial necrosis, monitoring for reperfusion arrhythmias, and assessment of changes in chest pain intensity.

CONCLUSION

The early detection of failed reperfusion is critical if incremental strategies to enhance myocardial salvage are to be considered. Continuous ST-segment monitoring is a relatively inexpensive, reliable, and accurate tool for assessing real-time myocardial perfusion.

Predictors of quality of life 6 months and 1 year after acute myocardial infarction

BACKGROUND

Quality of life (QOL) is an increasingly important outcome measure after hospital admission for acute myocardial infarction (AMI). However, the ability to adjust these outcomes for differences between compared groups of patients is limited because the predictors of QOL after AMI are unknown.

METHODS

To identify any clinical, demographic, and psychosocial characteristics of patients at admission that were independent predictors of QOL 6 months and 1 year after AMI, we measured physical and mental QOL (Short Form-36 Physical and Mental Component summary scores) and overall QOL (EuroQol health perception scale) in a prospective cohort of 587 patients admitted at 10 hospitals in Quebec. A set of plausible multivariate linear regression models was created for each outcome measure with use of the Bayesian Information Criterion.

RESULTS

Mean physical, mental, and overall QOL scores corresponding to the time immediately before admission (baseline) were 45 (95% confidence interval [CI] 44-46), 47 (95% CI 46-48), and 70 (95% CI 68-72), respectively. By 1 year, mean physical, mental, and overall QOL scores were close to baseline (45 [95% CI 44-46], 48 [95% CI 47-49], and 73 [95% CI 71-74], respectively). The predictors of physical, mental, and overall QOL were similar at 6 months and 1 year. Important predictors of physical QOL were the corresponding score at baseline, age, and previous bypass surgery (beta coefficients at 1 year: 5 [per 10-point difference in baseline score], -1 [per 10-year age difference], 5.3; 95% CIs 4 to 5, -2 to -1, -9.2 to -1.3, respectively). Predictors of mental QOL were the corresponding score at baseline and depression (beta coefficients at 1 year: 3 [per 10-point difference in baseline score], -3 [per 10-point difference in depression score]; 95% CIs 2 to 4, -5 to -2, respectively). Predictors of overall QOL included the corresponding score at baseline and age (beta at 1 year: 2 [per 10-point score difference], -3 [per 10-year age difference]; 95% CIs 1 to 3, -4 to -1, respectively). Depression was also a predictor of impaired physical and overall QOL at 6 months (beta at 6 months: -1.6 [per 10-point score difference], -5.4 [per 10-point score difference]; 95% CIs -2.9 to -0.4, -7.7 to -3.2, respectively). No variables related to treatments received in-hospital were found in the most clinically relevant models.

CONCLUSIONS

These results suggest that age and psychosocial characteristics at baseline are the most important predictors of QOL after AMI. Other clinical characteristics and treatments received in-hospital do not appear to strongly affect patients' long-term perceptions of QOL.

Update on strategies to improve thrombolysis for acute myocardial infarction

Therapy for acute myocardial infarction involves rapid restoration of blood flow through a coronary artery that has been occluded by a ruptured atherosclerotic plaque. Thrombolytic therapy, the pharmacologic standard to achieve this outcome, significantly improves survival; however, current regimens have limitations: they can fail to achieve complete reperfusion, they can cause significant bleeding events, and they can result in reocclusion. In addition, complex regimens of some agents can cause dosing errors. Accordingly, newer compounds were developed to address some of these issues, and alternative strategies are being implemented. The combination of platelet glycoprotein IIb-IIIa receptor inhibitors plus thrombolytic agents produced promising results in clinical trials, including faster clot lysis and greater flow rates than either therapy alone. The addition of unfractionated heparin or low-molecular-weight heparin to thrombolytic-antiplatelet therapy is being evaluated, as is administration of thrombolytic-antiplatelet before percutaneous coronary intervention.

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.

Reappraising the role of immediate intervention following thrombolytic recanalization in acute myocardial infarction

Early studies indicated that after successful thrombolytic recanalization, adjunctive percutaneous transluminal coronary angioplasty (PTCA) was not appropriate, even when a significant residual stenosis was present. The aim of this study was to assess in-hospital clinical outcomes of patients with acute myocardial infarction (AMI) who underwent successful recanalization after thrombolytic therapy. The relation between repeat AMI/unstable angina and the severity of the stenosis, as well as other angiographic and clinical features was also examined. One hundred patients with AMI of <10 hours underwent coronary angiography 2 hours after receiving thrombolytic therapy. Salvage PTCA +/- stenting was performed if recanalization was unsuccessful (Thrombolysis In Myocardial Infarction [TIMI] trial grade 0 to 2), and no PTCA was undertaken if there was brisk anterograde flow (TIMI 3). Angiographic analysis was performed to assess the severity of the residual lesion, as well as the presence or absence of thrombus. Forty patients had unsuccessful recanalization, and of these, 36 underwent attempted PTCA. Of the 60 patients with TIMI 3 flow, 15 required repeat angiography and PTCA after repeat AMI (n = 13) or unstable angina (n = 2) within 5 days. Receiver-operating characteristic analysis indicated an optimum percent diameter stenosis predictor of 85% for repeat AMI/unstable angina. There was no additional relation to age, gender, time to thrombolysis, the infarct-related artery, or the presence of culprit lesion thrombus. After recanalization, a high-grade stenosis >85% is common (n = 25, 42.4%). This is associated with a 54% repeat AMI/unstable angina risk-a ninefold increase in the incidence of such events than in patients with lesions <85%. Thus, patients with narrowings >85% may benefit from early intervention rather than a conservative approach. Narrowings <85% have a 94% probability of no repeat AMI/unstable angina and do not require early intervention.

Predictors of bleeding complications after rescue coronary interventions

The purpose of this study was to determine predictors of bleeding complications after current rescue coronary interventions including stenting and adjunctive platelet inhibitors. Previous studies of rescue angioplasty for thrombolytic failure have identified variable rates of bleeding complications with balloon angioplasty alone. Although coronary stents and glycoprotein 2b/3a inhibitors have been shown to improve outcome in a wide variety of coronary interventions, the impact of these therapies on bleeding complications after rescue coronary intervention has not been determined. From 1996 through 1998, we treated 108 consecutive patients with rescue coronary intervention (defined as attempted coronary intervention within 12 hours of thrombolysis for ongoing symptoms or electrocardiogram [ECG] changes) including conventional percutaneous transluminal coronary artery (PTCA), stenting (n = 45), and glycoprotein 2b/3a inhibitor use (n = 31). In-hospital clinical outcomes were obtained in all patients, and univariate and multivariate predictors of bleeding complications were identified. In hospital, moderate to severe bleeding complications occurred in 17.6% of the cohort, but the rate of severe bleeding complications (2.7%) and vascular repair (1.9%) were low. Independent predictors of bleeding complications were age > 60y, female gender, cardiogenic shock, and streptokinase use. Neither the delayed use of abciximab (on average 4 hours after thrombolytic therapy initiation) nor the use of rescue stenting were predictors of increased moderate to severe bleeding complications. Current rescue coronary intervention, including stents and platelet inhibitors, is associated with a low rate of severe bleeding complications. Moderate to severe bleeding complications were more common in selected subgroups of patients but not increased significantly by stenting or delayed abciximab use.

Angiographic and clinical outcomes after rescue coronary stenting

The role of coronary stenting in improving outcomes after failed thrombolysis has not been well described. This study represents a registry of rescue coronary interventions performed during a 3 year period in which interventional treatment was changing for this high risk population. We analyzed acute angiographic results and clinical outcomes in 108 consecutive patients treated for thrombolytic failure with either balloon angioplasty (n = 63) or coronary stenting (n = 45). The overall in-hospital mortality rate was 5.5%, and there was no increase in complications in the stent group. Coronary stenting was associated with improved angiographic results including lower residual stenosis in the culprit artery (15 +/- 10% vs. 31 +/- 22%, P < 0.001) without increasing bleeding complications. The rate of in-hospital and long term target vessel revascularization in the stent group was significantly lower than in the unmatched PTCA group. Rescue coronary stenting is safe, improves acute angiographic results compared to PTCA alone and leads to excellent in-hospital and long term outcomes.

Treatment and outcome of myocardial infarction in hospitals with and without invasive capability. Investigators in the National Registry of Myocardial Infarction

OBJECTIVES

We sought to determine the extent to which the capability of a hospital to perform invasive cardiovascular procedures influences treatment and outcome of patients admitted with acute myocardial infarction (AMI).

BACKGROUND

Patients with AMI are usually transported to the closest hospital. However, relatively few hospitals have the capability for immediate coronary arteriography, percutaneous transluminal coronary angioplasty (PTCA) or coronary artery bypass graft surgery (CABG), should these interventions be needed.

METHODS

The 1,506 hospitals participating in the National Registry of Myocardial Infarction 2 were classified according to their highest level of invasive capability: 1) none (noninvasive, 28.1%); 2) coronary arteriography (cath-capable, 25.2%); 3) coronary angioplasty (PTCA-capable, 7.4%); and 4) bypass surgery (CABG-capable, 39.2%). Treatment and in-hospital outcomes were assessed for 305,812 patients admitted from June 1994 through October 1996. Follow-up through 90 days was ascertained in a subset of 30,402 patients enrolled simultaneously in both the National Registry of Myocardial Infarction (NRMI) 2 and the Cooperative Cardiovascular Project (CCP).

RESULTS

The proportion of patients receiving initial reperfusion intervention was only slightly higher at the more invasive hospitals (noninvasive 32.5%, cath-capable 31.2%, PTCA-capable 32.9% and CABG-capable 35.9%, p < 0.001 by chi-square statistic). Among thrombolytic recipients, median door-to-drug time interval differed little among hospital types and ranged from 42 to 45 minutes. At cath-capable, PTCA-capable and CABG-capable hospitals, coronary arteriography was performed in 32.9%, 37.4% and 64.9%, respectively, and PTCA in 0.0%, 5.1% and 31.4%, both p < 0.001 by chi-square statistic. The proportion of patients transferred out to other facilities was 51.0%, 42.2%, 39.9% and 4.4% (p < 0.0001) among noninvasive, cath-capable, PTCA-capable and CABG-capable hospitals, respectively. Among patients in the combined NRMI and CCP data set, mortality at 90 days postinfarction was similar among patients initially admitted to each of the four hospital types.

CONCLUSIONS

Although patients with AMI admitted to hospitals without invasive cardiac facilities have a high likelihood of subsequent transfer to other facilities, their likelihood of receiving a reperfusion intervention at the first hospital, their door to thrombolytic drug intervals and their 90-day survival rates are similar to those of patients initially admitted to more invasively equipped hospitals. These data suggest that a policy of initial treatment of myocardial infarction at the closest medical facility is appropriate medical practice.

Predictors of cardiogenic shock after thrombolytic therapy for acute myocardial infarction

OBJECTIVES

This study characterized clinical factors predictive of cardiogenic shock developing after thrombolytic therapy for acute myocardial infarction (AMI).

BACKGROUND

Cardiogenic shock remains a common and ominous complication of AMI. By identifying patients at risk of developing shock, preventive measures may be implemented to avert its development.

METHODS

We analyzed baseline variables associated with the development of shock after thrombolytic therapy in the Global Utilization of Streptikonase and Tissue-Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) trial. Using a Cox proportional hazards model, we devised a scoring system predicting the risk of shock. This model was then validated in the Global Use of Strategies to Open Occluded Coronary Arteries (GUSTO-III) cohort.

RESULTS

Shock developed in 1,889 patients a median of 11.6 h after enrollment. The major factors associated with increased adjusted risk of shock were age (chi2 = 285, hazard ratio [95% confidence interval] 1.47 [1.40, 1.53]), systolic blood pressure (chi2 = 280), heart rate (chi2 = 225) and Killip class (chi2 = 161, hazard ratio 1.70 [1.52, 1.90] and 2.95 [2.39, 3.63] for Killip II versus I and Killip III versus I, respectively) upon presentation. Together, these four variables accounted for >85% of the predictive information. These findings were transformed into an algorithm with a validated concordance index of 0.758. Applied to the GUSTO-III cohort, the four variables accounted for > 95% of the predictive information, and the validated concordance index was 0.796.

CONCLUSIONS

A scoring system accurately predicts the risk of shock after thrombolytic therapy for AMI based primarily on the patient's age and physical examination on presentation.

A Double-Blind Multicenter Comparison of the Efficacy and Safety of Saruplase and Urokinase in the Treatment of Acute Myocardial Infarction: Report of the SUTAMI Study Group

Background: Urokinase or two-chain urokinase-type plasminogen activator has been shown to be effective in the treatment of acute myocardial infarction. Its parent molecule, single-chain urokinase-type plasminogen activator (scu-PA), unlike urokinase, can selectively activate fibrin-bound plasminogen. The induced clot lysis is amplified by plasmin-triggered conversion of scu-PA to urokinase and by further plasmin generation. The aim of our study was to compare the efficacy and safety of recombinant unglycosylated scu-PA, or saruplase, and urokinase at doses considered optimal in patients with acute myocardial infarction within 6 hours of onset of pain. Methods and results: In a double-blind trial 543 patients were randomized to saruplase (20 mg bolus + 60 mg/hr) or urokinase (1.5 million unit bolus + 1.5 million units/hr). Primary endpoint: The patency rates at 24-72 hours were 75.4% (95% CI 70.3-80.5%) for saruplase and 74.2% (95% CI 69.0-79.4%; P = 0.77) for urokinase. Secondary endpoint: The incidence of bleeding events in both groups was 10.7%. There were three hemorrhagic strokes in the saruplase group (ns). Other efficacy and safety evaluations: Apart from the generation of more fibrinogen degradation products under saruplase, the changes in hemostatic parameters did not differ. Hospital mortality was 4.4% for saruplase and 8.1% for urokinase. This nonsignificant difference was maintained for 1 year. Conclusion: The efficacy and safety of saruplase and urokinase in the regimens used are very similar.

Improving the Efficacy and Stability of Coronary Reperfusion Following Thrombolysis: Exploring the Thrombin Hypothesis

A major assumption in the treatment of patients with acute myocardial infarction (MI) implies that the speed of coronary arterial reperfusion correlates directly with the overall extent of myocardial salvage, and that the extent of mycardial salvage, in turn, determines the absolute reduction in patient mortality. While a growing experience has made it clear that myocardial salvage-independent (time-independent) mechanisms of benefit also exist, few would argue with the hypothesis that the greatest benefit derived from coronary thrombolysis occurs with early (time-dependent) treatment. Thus, improvements in the efficacy of reperfusion and the stability of reperfusion are likely to have considerable impact on patient outcome.

Increased thrombin activity correlates with increased ischemic event rate after percutaneous transluminal coronary angioplasty: lack of efficacy of locally delivered urokinase

BACKGROUND

Angiographic thrombus is associated with increased coronary occlusion and restenosis rates after angioplasty. Administration of intracoronary urokinase decreases the incidence of thrombus but is associated with an increased periprocedural event rate, including stroke and myocardial infarction. An alternative approach is to deliver the agent directly into the arterial wall, thereby reducing the thrombotic substrate in the absence of a systemic effect of the delivered agent.

OBJECTIVE

This randomized, double-blind, prospective study correlated intracardiac fibrinopeptide A levels with the ischemic events after angioplasty and evaluated whether locally administered urokinase could reduce the event rate.

METHODS

Fifty-four patients with acute coronary syndromes were randomly assigned to local delivery of urokinase or saline. Levels of fibrinopeptide A, a marker of thrombin activity, were obtained before and after administration of heparin, after 2 balloon inflations, and at the end of the procedure in 43 patients and were correlated with ischemic events within the 6-month follow-up period (death, myocardial infarction, or recurrent ischemia).

RESULTS

Multivariant analysis revealed that an elevated fibrinopeptide A level before angioplasty significantly correlated with an increased likelihood of an adverse event over the 6-month clinical follow-up. A postangioplasty reduction in the fibrinopeptide A level was noted in control patients (P <.001), but not after local urokinase administration, and the final fibrinopeptide A level was higher in the urokinase group (P =.02). Urokinase had no effect on the procedural results. On follow-up more patients receiving urokinase (13 of 27) had ischemic events than did control patients (6 of 25, P =.04). Most events were recurrent ischemia caused by restenosis.

CONCLUSIONS

Heparin-resistant thrombin activity, as evidenced by an increased fibrinopeptide A level correlates with ischemic events on long-term follow-up. Local delivery of urokinase increased the event rate.

[Prehospital thrombolysis with rt-PS. Reperfusion strategy in a time management concept of acute myocardial infarct]

PATIENTS AND METHOD

Prehospital thrombolysis was performed on 93 patients during a time period of 6 years (3/1992 to 9/1998) in an urban area. Thrombolysis with rt-PA (20 mg rt-PA bolus, 30 minute infusion with 30 mg rt-PA) could be started within 2 hours after the onset of symptoms in 67 patients (73.6%).

RESULTS

The time gain from prehospital thrombolysis amounted to 38 +/- 14 minutes. Bleeding complications were not observed in the prehospital setting, but 2 patients suffered from intracerebral hemorrhage subsequently and died in the hospital. An aborted infarction (CKmax < 200 U/l and no new Q-waves) was observed in 18 patients (20%) and another 23 patients (25%) had a limitation of infarct size (CKmax < 500 U/l or no new Q-waves) despite obvious signs of myocardial ischemia in the first ECG.

CONCLUSION

Our experience demonstrates a considerable time gain for prehospital thrombolysis even for an urban area. Accelerated rt-PA is a safe and comfortable thrombolysis regime.