Prospective evaluation of eligibility for thrombolytic therapy in acute myocardial infarction

In-hospital mortality among consecutive patients with ST-Elevation myocardial infarction in modern primary percutaneous intervention era ~ Insights from 15-year data of single-center hospital-based registry ~

Objective

To clarify the association of detailed angiographic findings with in-hospital outcome after primary percutaneous coronary intervention (p-PCI) for ST-elevation myocardial infarction (STEMI) in Japan.

Background

Data regarding the association of detailed angiographic findings with in-hospital outcome after STEMI are limited in the p-PCI era.

Methods

Between January-2004 and December-2018, 1735 patients with STEMI (mean age, 68.5 years; female, 24.6%) who presented to the hospital in the 24-hours after symptom onset and underwent p-PCI were evaluated using the disease registries. The registry is an ongoing, retrospective, single-center hospital-based registry.

Results

The 30-day mortality rate and in-hospital mortality rate were 7.7% and 9.2%, respectively. Independent predictors of in-hospital mortality were ejection fraction (EF) < 40% [adjusted Odds Ratio (aOR), 4.446, p < 0.001], culprit lesions in the left coronary artery (LCA) (aOR, 2.940, p < 0.001) compared with those in the right coronary artery, Killip class > II (aOR, 7.438; p < 0.001), chronic kidney disease (CKD) (aOR, 4.056; p < 0.001), final thrombolysis in myocardial infarction (TIMI) grades 0/1/2 (aOR, 1.809; p = 0.03), absence of robust collaterals (aOR, 17.309; p = 0.01) and hypertension (aOR, 0.449; p = 0.01).

Conclusions

Among the consecutive patients with STEMI, the in-hospital mortality rate after p-PCI significantly improved in the second half. Not only CKD, Killip class > II, and EF < 40%, but also the angiographic findings such as culprit lesions in the LCA, absence of very robust collaterals, and final TIMI grades <3 were associated with an increased risk of in-hospital mortality.

Inferior ST-Elevation Myocardial Infarction Presenting When Urgent Primary Percutaneous Coronary Intervention Is Unavailable: Should We Adhere to Current Guidelines?

The pivotal studies that led to the recommendations for emergent reperfusion therapy for ST-elevation myocardial infarction (STEMI) were conducted for the most part over 25 years ago. At that time, contemporary standard treatments including aspirin, statin, and even anticoagulation were not commonly used. The 2013 American College of Cardiology Foundation (ACCF)/American Heart Association (AHA) guidelines and the 2017 European Society of Cardiology guidelines give a class I recommendation (with the level of evidence A) for primary percutaneous coronary intervention (pPCI) in patients with STEMI and ischemic symptoms of less than 12 h. However, if the patient presents to a hospital without pPCI capacity, and it is anticipated that pPCI cannot be performed within 120 min of first medical contact, fibrinolytic therapy is indicated (if there are no contraindications) (class I indication, level of evidence A). Our review of the pertinent literature shows that the current recommendation for inferior STEMI is based on the level of evidence lower than A. We can consider level B even C, supporting the recommendation for fibrinolytic therapy if pPCI is not available for inferior STEMI.

Cost-effectiveness of optimal use of acute myocardial infarction treatments and impact on coronary heart disease mortality in China

BACKGROUND

The cost-effectiveness of the optimal use of hospital-based acute myocardial infarction (AMI) treatments and their potential impact on coronary heart disease (CHD) mortality in China is not well known.

METHODS AND RESULTS

The effectiveness and costs of optimal use of hospital-based AMI treatments were estimated by the CHD Policy Model-China, a Markov-style computer simulation model. Changes in simulated AMI, CHD mortality, quality-adjusted life years, and total healthcare costs were the outcomes. The incremental cost-effectiveness ratio was used to assess projected cost-effectiveness. Optimal use of 4 oral drugs (aspirin, β-blockers, statins, and angiotensin-converting enzyme inhibitors) in all eligible patients with AMI or unfractionated heparin in non-ST-segment-elevation myocardial infarction was a highly cost-effective strategy (incremental cost-effectiveness ratios approximately US $3100 or less). Optimal use of reperfusion therapies in eligible patients with ST-segment-elevation myocardial infarction was moderately cost effective (incremental cost-effectiveness ratio ≤$10,700). Optimal use of clopidogrel for all eligible patients with AMI or primary percutaneous coronary intervention among high-risk patients with non-ST-segment-elevation myocardial infarction in tertiary hospitals alone was less cost effective. Use of all the selected hospital-based AMI treatment strategies together would be cost-effective and reduce the total CHD mortality rate in China by ≈9.6%.

CONCLUSIONS

Optimal use of most standard hospital-based AMI treatment strategies, especially combined strategies, would be cost effective in China. However, because so many AMI deaths occur outside of the hospital in China, the overall impact on preventing CHD deaths was projected to be modest.

Cardiogenic shock and heart failure post-percutaneous coronary intervention in ST-elevation myocardial infarction: observations from "Assessment of Pexelizumab in Acute Myocardial Infarction"

BACKGROUND

Mortality after ST-elevation myocardial infarction (STEMI) has reduced with reperfusion by primary percutaneous coronary intervention (PCI), which may have impacted on the adverse outcomes of cardiogenic shock (CS) and congestive heart failure (CHF).

METHODS AND RESULTS

In the APEX-AMI trial, 5,745 patients with STEMI and planned primary PCI were randomly assigned pexelizumab or matching placebo. Post-randomization CS or CHF was adjudicated by a clinical endpoints committee. Treatment assignment to pexelizumab did not influence either endpoint or mortality rates. Cardiogenic shock developed in 196 patients (3.4%) at a median of 6.0 hours (interquartile range 3.9-28.3) post-randomization, and mortality at 90 days was 54.6%. Congestive heart failure occurred in 254 of patients (4.4%) at a median of 2.6 days (IQR 1.0-16.6), and mortality through 90 days was 10.2%; mortality among those with neither endpoint was 2.1%. Patients with CS or CHF were older, were more often female, and had more hypertension and diabetes, but smoked less compared with non-CS/CHF patients (all P < .05). Independent mortality predictors among those with CS or CHF were hyperlipidemia and a history of angina (interaction P = .011 and .008, respectively); procedural predictors among survivors to PCI were pre-PCI Thrombolysis In Myocardial Infarction (TIMI) flow 0-1 and post-PCI TIMI flow <3 (P = .013 and <.0001, respectively).

CONCLUSIONS

Survival after CS remains poor despite aggressive reperfusion. Both CS and CHF remain the major causes of death among STEMI patients undergoing primary PCI. Future studies should examine treatments that aim to reduce mortality in these highest risk patients.

Implications and reasons for the lack of use of reperfusion therapy in patients with ST-segment elevation myocardial infarction: findings from the CRUSADE initiative

BACKGROUND

Prompt reperfusion for patients with ST-segment elevation myocardial infarction (STEMI) is a class I guideline recommendation and has been shown to reduce mortality. However, many STEMI patients in contemporary practice still do not receive any form of reperfusion therapy.

METHODS

We evaluated 8,578 patients with STEMI from 226 US hospitals participating in the CRUSADE quality improvement initiative from September 2004 to December 2006 to determine the proportion of eligible patients who received an attempt at reperfusion therapy and factors associated with lack of reperfusion among patients without a contraindication to reperfusion. STEMI patients were classified into 3 groups: (1) patients eligible for reperfusion and for whom reperfusion was attempted; (2) patients eligible for reperfusion and for whom reperfusion was not attempted; and (3) patients who were ineligible for reperfusion because of identified contraindications. We compared patient characteristics, treatments, and outcomes among the groups and identified factors independently associated with lack of reperfusion use among eligible patients.

RESULTS

Of the 8,578 patients with STEMI, 881 patients (10.3%) had a documented contraindication to reperfusion, 7,080 (82.5%) received fibrinolysis or underwent an attempt at primary percutaneous coronary intervention, and 617 reperfusion-eligible patients (7.2%) had no attempt to administer reperfusion. Primary reasons for contraindications were identified as absence of an ischemic indication (n = 474; 53.8%), bleeding risk (n = 147; 16.7%), patient-related reasons (n = 223; 25.3%), and other (n = 37; 4.2%). The strongest factors associated with not attempting reperfusion among the reperfusion-eligible population were older age, heart failure at presentation, noncardiac surgical center, prior stroke, and female sex. Compared with patients receiving an attempt at reperfusion, adjusted in-hospital mortality rates were higher for patients with a documented reperfusion contraindication (adjusted odds ratio 1.77, 95% CI 1.28-2.45) and in eligible patients who did not receive reperfusion (adjusted odds ratio 1.64, 95% CI 1.07-2.50).

CONCLUSIONS

More than 7% of STEMI patients without a reperfusion contraindication did not have an attempt to administer reperfusion therapy, and this was associated with greater in-hospital mortality. Age, sex, and comorbidity were factors related to lack of attempting reperfusion among apparently eligible patients. Quality improvement efforts should focus on maximizing reperfusion use among all eligible STEMI patients and in addressing the processes by which contraindications are defined, clinically determined, and reported.

Mechanical complications after percutaneous coronary intervention in ST-elevation myocardial infarction (from APEX-AMI)

A decrease in mechanical complications after ST-elevation myocardial infarction may have contributed to improved survival rates associated with reperfusion by primary percutaneous coronary intervention (PCI). Mechanical complications occurred in 52 of 5,745 patients (0.91%) in the largest reported randomized trial in which primary PCI was the reperfusion strategy. The frequencies were 0.52% (30) for cardiac free-wall rupture (tamponade), 0.17% (10) for ventricular septal rupture, and 0.26% (15) for papillary muscle rupture (3 patients had 2 complications). Ninety-day survival rates were 37% (11) for cardiac free-wall rupture, 20% (2) for ventricular septal rupture, and 73.3% (11) for papillary muscle rupture. These mechanical complications occurred at a median of 23.5 hours (interquartile range 5.0 to 76.8) after symptom onset and were associated with 44% (23 of 52) survival through 90 days, which accounted for 11% of the 90-day mortality. Factors associated with mechanical complications were older age, female gender, Q waves, presence of radiologic pulmonary edema, and increased prerandomization troponin levels. In conclusion, rates of mechanical complications are lower with primary PCI than those previously reported after fibrinolytic therapy.

Do patients with heart failure appropriately undergo invasive procedures post-myocardial infarction? Results from a prospective multicentre study

BACKGROUND

The degree of adherence to guideline recommendations that patients following myocardial infarction (MI) with congestive heart failure (CHF) undergo early angiography, and angioplasty if indicated, is unknown.

METHODS

We prospectively evaluated the use of invasive procedures in patients with segment-elevation myocardial infarction (STEMI), non-STEMI and CHF, admitted in 1 month to 16 Australian hospitals.

RESULTS

Of 475 post-MI patients (248 (52.2%) with STEMI), 112 (23.6%) had CHF, (57 (23.0%) with STEMI). Patients with CHF, compared with those without CHF, were older (67.8 vs 63.2 years; P = 0.002) and were more often women (34 vs 24%, P = 0.03), but had similar rates of other risk factors. Compared with post-MI patients without CHF, patients with CHF had fewer invasive procedures: angiography 72.3% versus 85.1% (P = 0.002) and angioplasty 33.9% versus 52.9% (P < 0.001) (12 (2.5%) patients underwent coronary surgery in-hospital); and among STEMI patients (angiography 72.3% CHF vs 89.5% no CHF [P < 0.001]; angioplasty 50.9% CHF vs 69.1% no CHF [P = 0.011]); these differences remained significant after adjustment for clinical covariates. Of the 121 (25.5%) post-MI patients aged > or =75 years, compared with those <75 years, the frequencies of angiography and angioplasty procedures were 66.1% versus 87.6% (P < 0.001) and 33.9% versus 53.4% (P < 0.001), respectively; 66% of the elderly with, and without, CHF had angiography.

CONCLUSION

The presence of CHF post-MI resulted in lower rates of use of angiography and angioplasty, which was not explained by lower procedure rates in the elderly. As these guideline-recommended procedures may improve survival in patients with CHF post-MI, future strategies should aim to enhance their use.

Thrombolytic therapy use for acute myocardial infarction and outcome in Qatar

OBJECTIVE

Data on the outcome of patients treated with thrombolytic therapy in the Arab world is scarce. The main objective of this study is to study the 7-day morbidity and mortality rate and the rate of use of thrombolytic therapy in patients presenting with acute myocardial infarction treated with thrombolytic therapy in the Middle East.

METHODS

We conducted a retrospective analysis of prospectively collected data for all patients who were admitted to Coronary Care Unit in Cardiology Department in Hamad Medical during the period (1991-2001). Patients were divided into two groups in relation to ethnicity whether they received thrombolysis or not. In each group, the number of patients, age at the time of admission, gender, cardiovascular risk profile, therapy and outcome in regard of in-hospital complication and 7-day death as primary end point were analyzed.

RESULTS

Of the total 5388 patients admitted with acute myocardial infarction during the 10-year period, 66.3% (3567) with STE MI were found, 61.4% (2190) of them received thrombolytic therapy while 38.6% (1377) were not eligible for thrombolytic therapy. The remaining 33.7% (1821) were admitted with non-STE MI. In consideration of ethnic variation, patients with STE MI eligible for thrombolytic therapy, 29.6% (1598) were Qataris and 70.4% (3792) were non-Qataris. Thrombolytic therapy was administered to 25.9% (414) of Qatari patients and 51.3% (1947) of non-Qataris. The mortality rate of Qatari patients who received thrombolytic therapy was 9.2% (38) vs. 19.5% (231) who did not receive thrombolytic therapy (p<0.001). In non-Qatari patients, the mortality rate was 5.2% (102) for those who received thrombolytic therapy, while it was 8.6% (159) for those with no thrombolytic therapy (p<0.001). When compared to male patients, female patients with thrombolytic therapy had higher mortality rates (in both Qataris and non-Qataris) (20.5% vs. 6.1%; p value<0.001 and 16.1% vs. 9.4%; p<0.001, respectively), there were no significant differences between the ethnic groups in regard to in-hospital complications. Patients treated with thrombolytic therapy had lower incidence of in-hospital complication regarding acute heart failure, post-myocardial angina, heart block and arrhythmia. Thrombolytic therapy reduced mortality rate in acute myocardial infarction by 69%. Logistic regression analysis had shown that arrhythmia, acute heart failure, heart block, cardiogenic shock, diabetes mellitus and stroke were independent predictors of increased mortality. Thrombolysis was used in 61.4%, which is still underutilized when compared to a few available studies in the Gulf area, and to other studies in the developed world.

CONCLUSION

In the current study, use of thrombolysis in acute myocardial infarction was associated with significant decrease in in-hospital mortality and morbidity. Mortality rate was higher in the Qatari nationals when compared to non-Qataris. Reperfusion therapy may be underutilized in the developing world. Increased use of reperfusion therapy would result in reduced mortality rate. Global measures to encourage the use of reperfusion therapy including patients' education, and strategies to improve the health care system are needed.

Reperfusion treatment of ST-elevation acute myocardial infarction

Reperfusion treatment of ST-segment elevation myocardial infarction (STEMI) is one of the medical interventions with the largest potential for saving human lives, independently of age and gender. An attempt to reopen an acutely occluded coronary artery can be done within a wide array of possibilities, from the simple administration of aspirin to the combination of drugs and complex coronary artery interventions. Fibrinolytic drugs and aspirin represent the easiest way to attempt reperfusion and together offer an acceptable compromise between opportunity for treatment and efficacy. Other drugs and the use of invasive revascularization alternatives yield further advantages, and in some high-risk subgroups may be the most rational treatment approach. Beyond investigator's bias and dedication to either form of reperfusion treatment, interventions and/or drugs should be used as needed (and as possible) to increase the overall impact of reperfusion treatment in the community, taking advantage of the best potential of each approach. Most resources have been directed toward the improvement of reperfusion rates with the combination of fibrinolytic and antiplatelet drugs or with angioplasty. These efforts have certainly raised costs, but have not decisively improved clinical outcome nor have they broadened the impact of reperfusion treatment in the community. Indeed, the main shortcoming of reperfusion therapy is that the cohort of untreated patients is still larger than the cohort of treated patients. At a time when mortality of patients with STEMI reaching the hospital and receiving treatment has decreased significantly, the prehospital diagnosis and treatment of STEMI with the objective of enlarging the treated population and shortening the pretreatment delays is likely the best strategy to further reduce mortality. The need for a population approach to treatment of STEMI is even more obvious when considering the expanding patient load that continuously worsens its clinical risk profile, together with the increasing incidence of diabetes, obesity, hypertension, and smoking habits. The target for improving reperfusion treatment of STEMI in the future, and thereby saving more lives, seems now to involve a cultural change and fulfillment of an organizational mission more than an incremental improvement in the current pharmacologic or interventional approach. These epidemiologic and social aspects of contemporary medicine deserve full attention at a time when researchers, clinicians, and health care providers tend to focus primarily on technological advances.

A randomized trial comparing myocardial salvage achieved by coronary stenting versus balloon angioplasty in patients with acute myocardial infarction considered ineligible for reperfusion therapy

OBJECTIVES

We assessed myocardial salvage achieved by reperfusion with percutaneous coronary interventions (PCI) and compared stenting with balloon angioplasty (PTCA) in patients with acute myocardial infarction (AMI) ineligible for thrombolysis.

BACKGROUND

A substantial proportion of patients with AMI are currently considered ineligible for thrombolysis, and reperfusion treatment is frequently not recommended for them. It is not known whether these patients benefit from PCI.

METHODS

The Stent or PTCA for Occluded Coronary Arteries in Patients with Acute Myocardial Infarction Ineligible for Thrombolysis (STOPAMI-3) trial, a randomized, open-label study, included 611 patients with AMI who were ineligible for thrombolysis (lack of ST-segment elevation on the electrocardiogram, late presentation >12 h after symptom onset, and contraindications to thrombolysis). Patients were randomly assigned to receive either coronary artery stenting (n = 305) or PTCA (n = 306). Scintigraphic myocardial salvage index (proportion of the initial myocardial perfusion defect that was salvaged by reperfusion) was the primary end point of the study.

RESULTS

A considerable myocardial salvage was achieved with both stenting and PTCA. In patients assigned to receive stenting, the median size of the salvage index was 0.54 (25th and 75th percentiles, 0.29 and 0.87), as compared with a median of 0.50 (25th and 75th percentiles, 0.26 and 0.82) in the group assigned to receive PTCA (p = 0.20). Mortality at six months was 8.2% in the group of patients assigned to receive stenting and 9.2% in the group of patients assigned to receive PTCA (p = 0.69).

CONCLUSIONS

Patients with AMI who are currently considered ineligible for thrombolysis by conventional guidelines may greatly benefit from primary PCI. The benefit seems to be comparable when a strategy of stenting is compared with a strategy of PTCA in these patients.

The costs and benefits of community thrombolysis for acute myocardial infarction : a decision-analytic model

BACKGROUND

There is evidence that the earlier a patient reaches hospital and receives thrombolysis, the better the outcome. The GREAT (Grampian Region Early Anistreplase Trial) directly addressed the issue of early thrombolysis by evaluating, in a randomised controlled trial, the efficacy of thrombolysis in the community compared with that administered in hospital.

OBJECTIVE

This paper aimed to model the cost and benefits of community compared with hospital thrombolysis from the UK NHS perspective, using efficacy data from the GREAT.

METHODS

A decision-analytic approach was used to model these two alternatives. Resource use and cost estimates were estimated for a single tertiary centre. Estimates of effectiveness in life-years were obtained from the 4-year follow-up for patients recruited to the GREAT, using declining exponential approximation of life expectancy. Costs are in pounds sterling, 2000/1 values.

RESULTS

Community thrombolysis had an average life expectancy of 12.48 years and hospital thrombolysis had an average life expectancy of 12.39 years. Costs were 361 pounds sterling for community thrombolysis and 300 pounds sterling for hospital thrombolysis. Community thrombolysis led to an additional 0.09 years of life-expectancy gained compared with hospital thrombolysis at an additional cost of 61 pounds sterling per patient. Therefore, the incremental cost per life-year gained for the community thrombolysis service over the hospital thrombolysis service was 667 pounds sterling. Sensitivity analysis showed that estimates of cost per life-year gained were most sensitive to the estimates of survival.

CONCLUSION

This model suggests that, from the UK NHS perspective, implementing community thrombolysis may lead to extra survival but at extra cost over hospital thrombolysis. Although the incremental cost per life-year is modest, judgements still have to be made, however, as to whether the extra benefits estimated are worth the additional resources required. This requires consideration of the local context in which the service may be introduced.

Adjunctive use of direct thrombin inhibitors in patients receiving fibrinolytic therapy for acute myocardial infarction

The direct thrombin inhibitors hirudin and bivalirudin inhibit both fluid-phase and clot-bound thrombin. These agents have been extensively studied in clinical trials in comparison with intravenous unfractionated heparin (UFH), as adjuncts to fibrinolytic therapy for ST-elevation myocardial infarction (STEMI) and in percutaneous coronary intervention (PCI), and they are currently undergoing further evaluation in patients with non-ST elevation acute coronary syndromes (NSTEACS). In angiographic trials there were trends for patients treated with hirudin to be more likely to achieve Thrombolysis In Myocardial Infarction (TIMI) grade 3 flow at 90 minutes than patients treated with UFH (65% versus 57% in TIMI-5; 41% versus 33% in Hirudin for the Improvement of Thrombolysis [HIT]-4; statistically nonsignificant differences in both trials). In Montréal Heart Institute trials and the multicenter Hirulog and Early Reperfusion or Occlusion (HERO)-1 trial the use of bivalirudin was associated with an increased incidence of TIMI grade 3 flow (85% versus 31%, p = 0.006; and 48% versus 35%, p = 0.02, respectively). These studies used streptokinase as the fibrinolytic agent except in TIMI-5 where alteplase was used. The initial clinical outcomes studies (Global Use of Strategies to Open Occluded Coronary Arteries in Acute Coronary Syndromes [GUSTO]-IIA and TIMI-9A) were discontinued early because of a high incidence of intracerebral bleeding (approximately 1.8%). Patients in these studies had either STEMI or NSTEACS, and thus not all were treated with fibrinolytic therapy. These studies were recommenced as GUSTO-IIB and TIMI-9B, using lower dosages of hirudin (0.1 mg/kg bolus + 0.1 mg/kg infusion for 96 hours). Neither TIMI-9B nor GUSTO-IIB showed an improvement in efficacy (death or reinfarction) or an increase in bleeding with hirudin. However, in the 1015 patients with STEMI treated with streptokinase in GUSTO-IIB, there was a 40% reduction in the combined incidence of death or myocardial infarction at 30 days (8.6% versus 14.4%, odds ratio [OR] 0.57, 95% confidence interval [CI] 0.38-0.87, p = 0.004). In the HERO-2 trial, 17073 patients receiving streptokinase for STEMI were randomized to receive either bivalirudin (0.25 mg/kg bolus and 0.5 mg/kg infusion for 12 hours followed by 0.25 mg/kg) or UFH (5000 IU bolus and 800-1000 IU/h infusion titrated to an activated partial thromboplastin time [APTT] of 50-75 seconds) for a total of 48 hours. Thirty-day mortality was similar in both groups (10.8% with bivalirudin versus 10.9% with UFH, OR 0.99, 95% CI 0.90-1.09, p = 0.85). There was a 30% reduction in the incidence of reinfarction before 96 hours (1.6% with bivalirudin versus 2.3% with UFH, OR 0.70, 95% CI 0.56-0.87, p = 0.001). Patients treated with bivalirudin had significantly more moderate bleeding (1.4% versus 1.1% with UFH, OR 1.32, 95% CI 1.0-1.74, p = 0.05). In a meta-analysis of patients with STEMI in the Direct Thrombin Inhibitor Trialists' collaboration, direct thrombin inhibitors were found to reduce the rate of reinfarction at 30 days (3.9% versus 4.8% with UFH, OR 0.80, 95% CI 0.71-0.90, p < 0.001), but did not reduce mortality (9.1% versus 9.0%, OR 1.02, 95% CI 0.94-1.11, p = 0.68) or the combined incidence of death/reinfarction at 30 days (11.8% versus 12.4%, OR 0.95, 95% CI 0.88-1.02, p = 0.18). There was no increase in major bleeding or intracerebral bleeding with direct thrombin inhibitor therapy. In conclusion, direct thrombin inhibitors reduce reinfarction, but not mortality, in patients with STEMI treated with fibrinolytic therapy. The major benefit of direct thrombin inhibitors appears to be in patients undergoing PCI, particularly after STEMI.

Prospective Evaluation of Clinical Outcomes After Acute ST-Elevation Myocardial Infarction in Patients Who Are Ineligible for Reperfusion Therapy: Preliminary Results From the TETAMI Registry and Randomized Trial

Background— Treatment with lytics or primary percutaneous coronary interventions (PCI) reduces the mortality rate of patients with ST-elevation myocardial infarction (STEMI) presenting within 12 hours. Patients presenting >12 hours are generally considered to be ineligible for reperfusion therapy, and there are currently no specific treatment recommendations for this subgroup.

Methods— All patients with STEMI <24 hours were included in the Treatment with Enoxaparin and Tirofiban in Acute Myocardial Infarction (TETAMI) randomized trial or registry. Those patients who were ineligible for acute reperfusion, had no cardiogenic shock, and were not planned for revascularization within 48 hours were randomized to 1 of 4 antithrombotic regimens involving enoxaparin or unfractionated heparin (UFH), in combination with tirofiban or placebo for 2 to 8 days. A concurrent registry tracked STEMI patients coming in within <12 hours, and who underwent reperfusion. This registry also tracked the remaining STEMI patients who neither received reperfusion nor were enrolled in the TETAMI randomized trial. The demographics and clinical outcomes of all three groups (received reperfusion therapy, too late for reperfusion and enrolled in the randomized trial, neither received reperfusion therapy nor were enrolled in the randomized trial) were prospectively tracked.

Results and Conclusion— There were 2,737 patients who presented with STEMI or a new left branch bundle block (LBBB), of which 1,654 (60%) presented ≤12 hours. There were 1,196 (72%) of 1,654 patients who received reperfusion therapy. There were 458 (28%) of the 1,654 patients deemed “ineligible” for reperfusion, mostly because of a contraindication to lytics or for being “too old.” In contrast, 1,083 (40%) of 2,737 patients presented >12 hours. Apart from 34 of these patients who had a stuttering infarction and were referred for reperfusion, the remaining patients did not receive reperfusion therapy.

Registry patients who received reperfusion therapy, compared with TETAMI randomized patients (all of whom received antithrombotic therapy) and registry patients who did not receive reperfusion, were younger (61 years versus 63 years and 67 years), were more likely to be male (78% versus 73% and 63%), and had persistent ST-segment elevation as opposed to LBBB or Q waves. Registry patients who received reperfusion therapy had better clinical outcomes, even after adjusting for admission Killip class, compared with TETAMI randomized patients and registry patients who did not receive reperfusion therapy. TETAMI randomized patients had better outcomes than registry patients who did not receive reperfusion therapy.

The major obstacle to expanding the delivery of reperfusion therapy to patients with STEMI is the large fraction of patients who present too late for reperfusion therapy. Examination of prospectively gathered data on STEMI patients who are ineligible for reperfusion may help optimize their treatment.

Therapy-dependent influence of time-to-treatment interval on myocardial salvage in patients with acute myocardial infarction treated with coronary artery stenting or thrombolysis

BACKGROUND

The relationship between myocardial salvage and time-to-treatment interval in patients with acute myocardial infarction (AMI) treated with coronary artery stenting or thrombolysis has not been studied.

METHODS AND RESULTS

This study analyzed 264 patients with AMI randomized to coronary stenting (133 patients) or thrombolysis (131 patients) in the setting of 2 randomized trials. Patients were divided into the following 3 groups defined by tertiles of the time-to-treatment interval: lower tertile (<165 minutes), middle tertile (165 to 280 minutes), and upper tertile (>280 minutes). Paired scintigraphic examinations were performed to obtain salvage index, which was the primary end point of the study. In the group with thrombolysis, the salvage index (median [25th; 75th] percentile) was 0.45 (0.16; 0.83) in the lower, 0.29 (0.17; 0.48) in the middle, and 0.20 (0.04; 0.46) in the upper tertile (P=0.03). In the group with stenting, the salvage index was 0.56 (0.49; 0.75) in the lower, 0.57 (0.36; 0.73) in the middle, and 0.57 (0.32; 0.75) in the upper tertile (P=0.59). In patients treated with stenting, the salvage index was greater than in patients treated with thrombolysis in the lower (0.56 versus 0.45, P=0.09), middle (0.57 versus 0.29, P=0.0003), and upper (0.57 versus 0.20, P=0.0005) tertiles of the time-to-treatment interval.

CONCLUSIONS

The influence of the time-to-treatment interval on the myocardial salvage in patients with AMI depends on the type of reperfusion therapy. Coronary artery stenting was superior to thrombolysis independent of the time-to-treatment intervals, and the difference in benefit increased with more prolonged time from symptom onset.

Associations between ST depression, four year mortality, and in-hospital revascularisation in unselected patients with non-ST elevation acute coronary syndromes

OBJECTIVE

To determine the associations between changes on the presenting ECG, in-hospital revascularisation, and four year mortality in patients with non-ST elevation acute coronary syndromes.

DESIGN

Prospective evaluation of all consecutive patients admitted in 1993 to the Green Lane Hospital coronary care unit, Auckland, New Zealand. Late follow up was undertaken at a median of 52 months. The ECGs were analysed after the hospital admission.

SETTING

Tertiary referral centre with direct local coronary care unit admissions.

INTERVENTIONS

Patients underwent physician recommended in-hospital revascularisation or initial conservative management.

RESULTS

The four year survival was 88% in the 115 patients who underwent revascularisation (65 (19%) percutaneous and 53 (16%) surgical revascularisation), compared with 75% in 316 patients managed conservatively (p = 0.024). Four year survival for patients undergoing revascularisation versus initial conservative management with respect to ECG groups was: no ECG changes (n = 101), 97% v 92% (p = 0.35); T wave inversion or 0.5 mm ST depression (n = 108), 89% v 78% (p = 0.18); ST depression > or = 1 mm (n = 122), 80% v 58% (p = 0.014); chi2 = 29, p < 0.001 for the linear trend across the groups. On multivariate analysis, independent predictors of four year mortality were: age (odds ratio (OR) 1.05, 95% confidence interval (CI) 1.01 to 1.08; p = 0.0046); ECG group (OR 1.88, 95% CI 1.21 to 2.95; p = 0.043); radiological pulmonary oedema (OR 2.81, 95% CI 1.18 to 7.05; p = 0.025); and revascularisation (OR 0.43, 95% CI 0.20 to 0.90; p = 0.023).

CONCLUSIONS

Among unselected patients with non-ST elevation acute coronary syndromes, in-hospital revascularisation is associated with decreased mortality at up to four years after admission. This association appears greater in patients with ST depression of > or = 1 mm on the presenting ECG.

Interaction between arrival time and thrombolytic treatment in determining early outcome of acute myocardial infarction

BACKGROUND

Shortening prehospital delay has been identified as an important means of improving responses to reperfusion treatment. If this increases the risk profile of the population delivered to hospital, it may paradoxically cause a deterioration in hospital mortality.

OBJECTIVE

To examine the interaction between arrival time (time from onset of chest pain to arrival at hospital) and thrombolytic treatment in determining the early outcome of acute myocardial infarction.

METHODS

Prospective cohort study of 1723 patients with acute myocardial infarction who were potentially eligible for thrombolytic treatment (ST elevation on ECG; arrival time < or = 12 hours).

RESULTS

All patients were eligible for thrombolysis but only 1098 (80%) received it. Patients who did not receive thrombolytic treatment were older (66 (58-73) v 61 (53-70) years, p < 0.001), more commonly female (32.1% v 24.8%, p < 0.01), and had higher frequencies of previous infarction (28.6% v 15.6%, p < 0.001) and left ventricular failure (37.5% v 26.9%, p < 0.01) than patients who received thrombolytic treatment. For the group as a whole, 30 day mortality was 11.7% and was unaffected by arrival time, but in patients who did not receive thrombolysis an arrival time of < or = 6 hours was associated with significantly higher 30 day mortality than an arrival time of 6-12 hours (24.3% v 2.6%, p = 0.002). Conversely, in patients who did receive thrombolysis an arrival time of < or = 6 hours was associated with a lower 30 day mortality than an arrival time of 6-12 hours (8.5% v 14.5%, p < 0.02).

CONCLUSIONS

Shortening prehospital delay in acute myocardial infarction will tend to increase the risk profile of patients presenting to emergency departments. The data presented here indicate that this may increase hospital mortality if underutilisation of thrombolytic treatment among high risk groups is not diminished.

The role of health informatics in clinical audit: part of the problem or key to the solution?

The concepts of quality assurance (for which clinical audit is an essential part), evaluation and clinical governance each depend on the ability to derive and record measurements that describe clinical performance. Rapid IT developments have raised many new possibilities for managing health care. They have allowed for easier collection and processing of data in greater quantities. These developments have encouraged the growth of quality assurance as a key feature of health care delivery. In the past most of the emphasis has been on hospital information systems designed predominantly for the administration of patients and the management of financial performance. Large, hi-tech information system capacity does not guarantee quality information. The task of producing information that can be confidently used to monitor the quality of clinical care requires attention to key aspects of the design and operation of the audit. The Myocardial Infarction National Audit Project (MINAP) utilizes an IT-based system to collect and process data on large numbers of patients and make them readily available to contributing hospitals. The project shows that IT systems that employ rigorous health informatics methodologies can do much to improve the monitoring and provision of health care.

Cardiovascular prevention before admission reduces mortality following acute myocardial infarction in patients with diabetes

OBJECTIVES

Previous studies have shown that patients with diabetes mellitus have an increased mortality after suffering from acute myocardial infarction (AMI). Patients with diabetes have several risk factors for cardiovascular disease. Our objective was to quantify the prevalence of pharmacological cardiovascular prevention at admission and relate such treatment to short and long-term mortality following AMI in patients with and without diabetes.

DESIGN AND SUBJECTS

All patients discharged from the Department of Internal Medicine at Helsingborg Hospital in 1996 and 1997 with a principal diagnosis of AMI were included in the study. Patients were divided into two groups according to the presence or absence of diabetes. Cardiovascular risk factors, on-going medication, type of ward following admission, peak creatine kinase MB mass (CKMB) and immediate treatment were registered. Information about death was obtained from the national register. Kaplan-Meier analysis was performed for life-expectancy.

RESULTS

A total of 673 patients with AMI were registered, of which 117 (17.4%) had diabetes. No differences in 30 days (17.1% vs. 15.3%) or 1-year (24.8% vs. 27.4%) mortality were seen between the diabetes and control groups, whereas the 2-year mortality was significantly higher in the diabetes group (40.2% vs. 29.1%). Cardiovascular risk factors occurred more often in the diabetes group and the use of aspirin, ACE-inhibitors, statins and diuretics was significantly more frequent. In patients treated with aspirin, in combination with either statin or angiotensin converting enzyme (ACE)-inhibitor, or both, no differences were seen in 30 days, 1 or 2-year mortality between groups.

CONCLUSION

In contrast to earlier studies we did not find an increased 30 days and 1-year mortality in patients with diabetes suffering from AMI. This discrepancy was linked to a higher frequency of pharmacological cardiovascular prevention, a finding supporting the hypothesis that survival of a diabetes patient after AMI could be affected by factors operating before the infarction.

Thrombolytics in infectious endocarditis associated myocardial infarction

The use of thrombolytics in the management of acute myocardial infarction in eligible patients is the accepted standard of practice. We present the case of an embolic myocardial infarction in the setting of acute infectious endocarditis, treated with thrombolytics, resulting in a massive intracerebral hemorrhage and the patient's death. Historical and current literature has shown a consistent and significant incidence of concurrent intracerebral mycotic aneurysms in the setting of infectious endocarditis. Despite this, a literature review of contraindications to the use of thrombolytics rarely recognizes endocarditis as a contraindication. It is imperative that the etiology for myocardial infarction be identified; if contraindications to thrombolytic treatment exist, alternative therapeutic interventions must be pursued. This case highlights the importance of the correct etiologic diagnosis of myocardial ischemia, and increases the awareness of the significant risks of intracerebral hemorrhage associated with the use of thrombolytics in the setting of endocarditis.

Opportunities for control of coronary heart disease in Australia

OBJECTIVE

To estimate the number of coronary events that could be prevented in Australia each year by the use of preventive and therapeutic strategies targeted to subgroups of the population based on their levels of risk and need.

METHODS

Estimates of risk reduction from the published literature, prevalence estimates of elevated risk factor levels from the 1995 National Health Survey and treatment levels from the Australian collaborating centres in the World Health Organization's MONICA Project were used to calculate numbers of coronary events preventable among men and women aged 35-79 years in Australia.

RESULTS

Approximately 14,000 coronary events could be avoided each year if the mean level of cholesterol in the population was reduced by 0.5 mmol/L, smoking prevalence was halved and prevalence of physical inactivity was reduced to 25%. This represents a reduction in coronary events of about 40%. Even with less optimistic targets, a reduction of 20% could be attained, while the achievement of some internationally recommended targets could lead to almost 50% reduction. In the short term, aggressive medical treatment of people with elevated levels of risk factors and established coronary disease offers the greatest opportunity for reducing coronary events.

CONCLUSION

A comprehensive approach to reduce levels of behavioural and biological risk factors and improve the use of effective treatment could lead to a large reduction in coronary event rates. In the long term, primary prevention--especially to reduce smoking, lower cholesterol levels and increase exercise--has the potential to reduce the population levels of risk and hence contain the national cost of coronary disease.

Corrected TIMI frame counts correlate with stenosis severity and infarct zone wall motion after thrombolytic therapy

BACKGROUND

The majority of patients with patent infarct-related arteries after thrombolytic therapy have slower than normal flow, which relates to myocardial perfusion.

METHODS

To evaluate the relationships between blood levels of creatine kinase (CK) and the corrected Thrombolysis in Myocardial Infarction (TIMI) frame count (CTFC), infarct artery stenosis, and left ventricular function, we studied 397 patients with a first myocardial infarction who underwent angiography at 3 weeks. TIMI flow grades, the CTFC, infarct artery stenosis, and infarct zone wall motion (by contrast ventriculography using the centerline method) were assessed, and CK levels (in units per liter) were measured hourly for the first 4 hours after streptokinase (1.5 x 10(6) U over 30-60 minutes) and then every 4 hours over the next 20 hours, all blinded to treatment and outcome.

RESULTS

Infarct artery stenosis and the CTFC, assessed as continuous variables, correlated in patients with patent infarct arteries (r = 0.33, P <.001). Also, there was a significant correlation between the CTFC and the sum of hypokinetic chords in the infarct zone (r = 0.15, P =.01). Patients with total occlusion or markedly slowed infarct artery flow (CTFC >100) had a higher fraction of chords with wall motion >2 SDs below normal (0.65 [0.41, 0.80] vs 0.37 [0.0, 0.67]) compared with patients with normal flow (CTFC < or =27) (P <.001). The rates of increase of median CK levels with respect to TIMI flow grades were 342 U/L/h for TIMI 3 versus 212 U/L/h for TIMI 2 versus 140 U/L/h for TIMI 0-1 (P <.0001).

CONCLUSIONS

Prolonged corrected TIMI frame counts correlate with stenosis severity in the infarct artery after infarction, infarct zone regional wall motion, and CK levels.

ECG criteria in diagnosis of acute myocardial infarction in the presence of left bundle branch block

BACKGROUND

The diagnosis of acute myocardial infarction in the presence of left bundle branch block is difficult. Recently a diagnostic ECG scoring system was suggested, showing good diagnostic abilities. This scoring system has never been tested in a prospective manner; we have done so and investigated if it might bear prognostic information.

METHODS

A prospective multi-centre study. Consecutive patients with left bundle branch block and suspicion of acute myocardial infarction, admitted to 14 Swedish coronary care units. Recruitment from March 1996 to December 1997. ECG registered on admission and after 12-24 h.

RESULTS

One hundred and fifty-eight patients were included, mean age 74.9 years. Seventy-six patients (48%) had an acute myocardial infarction. The proposed cut-off total score of > or = 3 of the ECG scoring system for the diagnosis of acute myocardial infarction had a sensitivity of 17.1% (95% CI 8.6-25.6%) and specificity of 94.0% (95% CI 88.9-99.1%). Clinical judgement of acute myocardial infarction resulted in a sensitivity of 15.8% (95% CI 7.6-24%) and specificity of 96.0% (CI 92.3-100%). No difference was seen in 3-month or 1-year survival between those with total ECG score > or = 3 versus total score < 3.

CONCLUSION

The diagnostic abilities of the proposed ECG criteria are low and not better than the clinical judgement. The criteria are therefore not suitable for screening patients with suspicion of acute myocardial infarction in the presence of left bundle branch block, nor do they seem to identify high risk patients.

Advances in the pharmacology of acute coronary syndrome. Platelet inhibition

The development of potent inhibitors of platelet aggregation has led to significant decreases in morbidity and mortality rates among patients undergoing percutaneous coronary intervention. Clinical trials have demonstrated that agents that block glycoprotein IIb/IIIa receptor-mediated platelet aggregation have an outcome benefit when used acutely in patients with chest pain and ST depression or elevated cardiac enzymes, leading to the integration of these agents into emergency medicine clinical practice. This article provides an overview of the pathophysiology of acute coronary syndrome and the pharmacology of platelet inhibition and reviews the evidence from the clinical trials pertaining to the use of these agents in the emergency department.

Medical treatment for acute coronary syndromes

The medical treatment of acute coronary syndromes with thrombolytic, antithrombin, and antiplatelet agents is a major area of research and a vast topic for clinical review. This review summarizes important recent findings on the background of existing pathological and clinical knowledge to provide an understanding of the basis of current therapy and the new therapies that are likely to be introduced in the near future. Current controversies regarding the management of these conditions and the choice between medical, interventional, and combined strategies in different situations are also discussed.

Cardiogenic shock with non-ST-segment elevation myocardial infarction: a report from the SHOCK Trial Registry. SHould we emergently revascularize Occluded coronaries for Cardiogenic shocK?

OBJECTIVES

We sought to determine the outcomes of patients with cardiogenic shock (CS) complicating non-ST-segment elevation acute myocardial infarction (MI).

BACKGROUND

Such patients represent a high-risk (ST-segment depression) or low-risk (normal or nonspecific electrocardiographic findings) group for whom optimal therapy, particularly in the setting of shock, is unknown.

METHODS

We assessed characteristics and outcomes of 881 patients with CS due to predominant left ventricular (LV) dysfunction in the SHOCK Trial Registry.

RESULTS

Patients with non-ST-segment elevation MI (n = 152) were significantly older and had significantly more prior MI, heart failure, azotemia, bypass surgery, and peripheral vascular disease than patients with ST-elevation MI (n = 729). On average, the groups had similar in-hospital LV ejection fractions (approximately 30%), but patients with non-ST-elevation MI had a lower highest creatine kinase and were more likely to have triple-vessel disease. Among patients selected for coronary angiography, the left circumflex artery was the culprit vessel in 34.6% of non-ST-elevation versus 13.4% of ST-elevation MI patients (p = 0.001). Despite having more recurrent ischemia (25.7% vs. 17.4%, p = 0.058), non-ST-elevation patients underwent angiography less often (52.6% vs. 64.1%, p = 0.010). The proportion undergoing revascularization was similar (36.8% for non-ST-elevation vs. 41.9% ST-elevation MI, p = 0.277). In-hospital mortality also was similar in the two groups (62.5% for non-ST-elevation vs. 60.4% ST-elevation MI). After adjustment, ST-segment elevation MI did not independently predict in-hospital mortality (odds ratio, 1.30; 95% confidence interval, 0.83 to 2.02; p = 0.252).

CONCLUSIONS

Patients with CS and non-ST-segment elevation MI have a higher-risk profile than shock patients with ST-segment elevation, but similar in-hospital mortality. More recurrent ischemia and less angiography represent opportunities for earlier intervention, and early reperfusion therapy for circumflex artery occlusion should be considered when non-ST-elevation MI causes CS.

Prognostic implications of ventricular fibrillation in acute myocardial infarction: new strategies required for further mortality reduction

OBJECTIVE

To determine the changing risk of ventricular fibrillation, the prognostic implications, and the potential long term prognostic benefit of earlier hospital admission, after acute myocardial infarction.

DESIGN

Prospective observational study.

SETTING

A district general hospital in east London.

PATIENTS

1225 consecutive patients admitted to a coronary care unit with acute myocardial infarction.

MAIN OUTCOME MEASURES

Time of onset of pain and ventricular fibrillation, and long term survival of patients admitted with acute myocardial infarction.

RESULTS

The rate of ventricular fibrillation in these hospital inpatients was high in the first hour from onset of pain (118 events/1000 persons/h; 95% confidence interval (CI) 50.7 to 231) and fell rapidly to an almost constant low level by six hours; 27.4% of patients with early ventricular fibrillation died in hospital, compared with 11.6% of those without (p < 0.0001), but mortality in patients who survived to hospital discharge was not altered by early ventricular fibrillation (five year survival: 75.0% (95% CI 60.0% to 84.8%) with ventricular fibrillation v 73.3% (95% CI 69.6% to 76.6%) without ventricular fibrillation).

CONCLUSIONS

Patients successfully resuscitated from early ventricular fibrillation have the same prognosis as those without ventricular fibrillation after acute myocardial infarction. Faster access to facilities for resuscitation must be achieved if major improvements in the persistently high case fatality of patients after acute myocardial infarction are to be made.

A review of the long term effects of thrombolytic agents

Unequivocal evidence exists that reperfusion therapy, when given within 12 hours after onset of symptoms, saves the lives of patients with acute myocardial infarction (MI). As a result, the routine use of such treatment has increased rapidly since the mid-1980s but the rates of utilisation have been relatively static over the last decade at approximately 50% of patients with acute MI. The major question arising in this respect is: is the benefit of reperfusion therapy, which is achieved during the acute phase in evolving MI, maintained on the long term? The main thrombolytic agents currently in use are streptokinase, alteplase, anistreplase, urokinase and reteplase. Other studies compared coronary angioplasty with thrombolytic therapy and investigated the effect of an additional angioplasty procedure after failed thrombolytic therapy. Furthermore, several studies have been performed to investigate the effect of initiation of reperfusion therapy before hospital admission. It is generally agreed that, in particular, patients receiving early treatment within 6 hours from onset of symptoms and patients with ST elevation benefit most from thrombolytic therapy. One would theoretically expect that infarct size reduction achieved by reperfusion therapy would also have a beneficial effect on the survival, not only during the hospital stay but also afterwards, resulting in diverging survival curves between patients who received reperfusion therapy and those who did not. However, the survival curves run perfectly parallel after hospital discharge from 1 year up to year 10 in most studies. The explanation for a lack of extra benefit may be a net result of combining the results of several subgroups. For example, thrombolytic therapy results in more frequent reinfarction especially in the first year, or patients with low left ventricular ejection fraction could survive the hospital phase because of effective thrombolytic therapy, but they survive at high risk. Although several trials suggest that primary percutaneous transluminal coronary angioplasty may be more beneficial than thrombolytic therapy in acute MI, these data should be interpreted cautiously unless confirmed by larger studies with long term results. In addition, evidence exists to suggest that administration of fibrinolytic treatment, under certain conditions, before hospital admission may lead to further improvement of a patient's prognosis. Again, further investigation is warranted. The conclusion is that clear evidence exists that the early improved survival after thrombolytic therapy has been shown to be maintained beyond a decade. However, the expected theorectical additional benefit of reperfusion therapy after hospital discharge has not been observed.

Changing the site of delivery of thrombolytic treatment for acute myocardial infarction from the coronary care unit to the emergency department greatly reduces door to needle time

OBJECTIVE

To quantify the change in door to needle time when delivery of thrombolytic treatment of acute myocardial infarction was changed from the coronary care unit to the emergency department.

DESIGN

A comparative observational study using prospectively collected data.

SETTING

Coronary care unit and emergency department of an Australian teaching hospital.

PARTICIPANTS

89 patients receiving thrombolysis in coronary care unit between June 1994 and January 1996, and 100 patients treated in the emergency department between April 1997 and May 1998.

INTERVENTIONS

From April 1997, by agreement between cardiology and emergency medicine, all patients with acute myocardial infarction receiving thrombolysis were treated by emergency physicians in the emergency department.

MAIN OUTCOME MEASURE

Door to needle time measured from time of arrival at the hospital to start of thrombolysis. Other outcomes included pain to needle time and mortality.

RESULTS

Median door to needle times were less for patients treated in the emergency department than in the coronary care unit (37 minutes, 95% confidence interval (CI) 33 to 44 v 80 minutes, 95% CI 70 to 89, respectively; p < 0.0001). Door to needle time was under 60 minutes in 83% of emergency department patients and 26% of coronary care unit patients (57% difference, 95% CI 45% to 69%; p < 0.0001). Median pain to needle time was less for emergency department patients than for coronary care unit patients (161 minutes, 95% CI 142 to 177 v 195 minutes, 95% CI 180 to 209; p = 0.004); times of less than 90 minutes occurred in 18% of emergency department patients v 1% of coronary care unit patients (17% difference, 95% CI 9% to 25%; p < 0.05). Overall mortality was similar in patients treated in the emergency department and the coronary care unit.

CONCLUSIONS

With a collaborative interdepartmental approach, thrombolytic treatment of acute myocardial infarction was more rapid in the emergency department, without compromising patient safety. This should improve the outcome in patients with infarcts treated with thrombolytic agents.

Prehospital delay time in acute myocardial infarction: an exploratory study on relation to hospital outcomes and cost

BACKGROUND

Short prehospital delay is associated with improved outcomes in myocardial infarction, but the impact on cost has not been tested. Shortening delay time could reduce health care expenditures.

METHODS AND RESULTS

Two hundred ninety-eight patients were examined with the use of a historic prospective design at 2 hospital sites. A secondary analysis was performed that used patients with confirmed myocardial infarction from the National Register of Myocardial Infarction and direct and indirect costs from the accounting system at the hospitals. Chi-square, Mann Whitney U, and Fisher exact tests were used for comparisons. Delay and 4 sets of variables were regressed on cost with the significant predictors used to construct a final model. The mean age was 71 +/- 14 years old; 62% were men. There were no major differences in demographics, cardiac history, risk factors, and admission characteristics between short and long delayers. Resource utilization and clinical outcomes were similar between the 2 groups; there was no difference in cost. Additional diagnostic procedures (odds ratio 2.92; 95% confidence interval 1.65-5.15) and complications (odds ratio 3.43; 95% confidence interval 2.03-5.82) were significant predictors of cost. Delay was not a predictor of high cost.

CONCLUSIONS

Short prehospital delay was not associated with improved clinical outcomes, nor did it predict cost. Explanations include (1) the low utilization of early reperfusion therapy in the short delay group, (2) the study lacked sufficient power to detect a difference in cost between short and long delayers, and (3) the severity of illness could not be adequately measured. This issue warrants further study because of the potential impacts on health care expenditures.

Relationship between corrected TIMI frame counts at three weeks and late survival after myocardial infarction

OBJECTIVES

To evaluate the corrected Thrombolysis in Myocardial Infarction (TIMI) frame count (CTFC) as a predictor of late survival after myocardial infarction.

BACKGROUND

Thrombolysis in Myocardial Infarction flow grades predict late survival after myocardial infarction. The CTFC provides a more reproducible measurement of infarct-related artery blood flow than the TIMI flow grade, and has been linked to 30-day outcomes, but it has not yet been established how the CTFC correlates with late survival.

METHODS

Of 1,001 patients with acute myocardial infarction presenting within 4 h of symptom onset, 882 underwent angiography at approximately three weeks. Infarct artery flow was assessed, blinded to clinical outcomes, according to the CTFC and TIMI flow grade. Late cardiac mortality and survival were determined in 97.5% of patients.

RESULTS

The mean CTFC was 40 +/- 29 in 644 patent infarct arteries (median, 34 [interquartile range, 24 to 47]). The CTFC, assessed as a continuous univariate variable, was found to be a predictor of five-year survival, as was the TIMI flow grade (both p < 0.001). On multivariate analysis, factors associated with five-year survival included the ejection fraction or end-systolic volume index (both p < 0.001); exercise duration (p = 0.005), age (p = 0.008), diabetes (p = 0.02) and CTFC (p = 0.02) or TIMI flow (p = 0.02). The same factors, except for the CTFC and TIMI flow grade, were predictors of 10-year survival.

CONCLUSIONS

The CTFC three weeks after myocardial infarction was an independent predictor of five-year survival, but not 10-year survival. Although the CTFC provided additional prognostic information within TIMI flow grades, its superiority was not demonstrated.

Direct thrombin inhibitors as adjuncts to thrombolytic therapy

Thrombolytic therapy aims to achieve rapid and sustained infarct-related artery patency, although this results in a procoagulant state. Heparin has limitations as an antithrombin agent, which has led to clinical investigation of alternative agents. Direct thrombin inhibitors, as adjuncts to thrombolytic therapy, have been shown to increase 90 minute Thrombolysis in Myocardial Infarction (TIMI)-3 flow rates and reduce reinfarction, when compared with heparin. These results have been achieved with an acceptable risk of bleeding, when administered in appropriate dosing regimens. When the direct thrombin inhibitor hirudin was administered at a mean of 34 and 50 minutes after thrombolytic therapy in large clinical trials, there was no reduction in mortality. In contrast, in several angiographic studies, direct thrombin inhibitors were administered prior to thrombolysis. The effect on mortality of the administration of hirulog prior to streptokinase is currently being examined.

Four-year survival of patients with acute coronary syndromes without ST-segment elevation and prognostic significance of 0.5-mm ST-segment depression

We prospectively evaluated all patients admitted to our coronary care unit during 1993 with ischemic chest pain but without ST-segment elevation on the presenting electrocardiogram, and determined the influence of the extent of ST-segment depression, measured using calipers and blinded to the outcome, on 4-year survival. The presenting symptoms of 367 patients (mean age 64 years) were coded according to the Braunwald classification, 86% being in class IIIB (primary unstable angina with rest angina within 48 hours) and 7.4% in class IIIC (postinfarction angina). Thirty-two patients (8.6%) had myocardial infarction at presentation (defined as a creatine kinase level exceeding twice the reference range within 18 hours). During hospitalization 97% of patients received aspirin, 67% received intravenous heparin, 37% underwent angiography, and 35% underwent revascularization. The vital status of 99% of the patients was determined after a median of 52 months (interquartile range 48 to 55). At follow-up, 88% of patients were taking aspirin, 45% were taking beta blockers, and 50% had undergone revascularization. The survival rate was 70% in patients with > or = 0.5-mm ST-segment depression (53%, 77%, and 82% survival for > or = 2-, 1-, and 0.5-mm ST-segment depression, respectively; p <0.0001). Patients with a normal electrocardiogram had a greater survival rate (94%) than that of patients with 0.5-mm ST-segment depression (82%, p = 0.020), but not significantly different from that of patients with T-wave inversion (84%, p = NS). Independent predictors of mortality (odds ratio [95% confidence interval]) were: age in yearly increments (1.05 [1.03 to 1.06], p = 0.003), revascularization during follow-up (0.40 [0.29 to 0.56], p = 0.006), pulmonary edema (3.45 [2.19 to 5.45], p = 0.007), and ST-segment depression (1.37 [1.20 to 1.55], p = 0.015). Thus, ST-segment depression of > or = 0.5 mm predicts 4-year survival in patients with acute ischemic syndromes.

Optimal treatment of patients with acute coronary syndromes and non-ST-elevation myocardial infarction

Non-ST-elevation myocardial infarction is usually indistinguishable from unstable angina at the initial presentation. The diagnosis is made subsequently when cardiac enzymes are found to be elevated either at admission or within 18 hours. Our understanding of the pathophysiology of acute coronary syndromes has advanced dramatically, and coupled with this understanding has been the introduction of new antiplatelet and antithrombotic treatments. The best way to integrate these treatments into percutaneous revascularization procedures has not yet been defined. In general, patients with non-ST-elevation myocardial infarction should be treated in the same way as those with unstable angina. Patients should be risk profiled at admission and subsequently according to clinical features, electrocardiographic findings, results of laboratory tests including measurement of troponins, and response to therapy. They should also be monitored carefully for signs of ischemia. Patients at low risk with a normal electrocardiogram and normal troponin T or I levels should be assessed for early discharge and outpatient assessment with exercise or pharmacological testing for inducible ischemia. Patients at intermediate risk should be treated with aspirin, unfractionated or low-molecular-weight heparin and, if unfractionated heparin is chosen, an adjunctive IIb/IIIa receptor antagonist. Patients at high risk should be treated with the same therapies and considered for expeditious angiography and revascularization as appropriate. A long-term secondary prevention strategy should be implemented.

Advances in antithrombotic therapy of acute myocardial infarction

The aim of the acute treatment of myocardial infarction is to restore, as promptly as possible, blood flow in the culprit vessel. Thrombolysis is a cornerstone of treatment, and direct coronary angioplasty (PTCA) is emerging as a valuable or even better alternative reperfusion strategy. The activation of hemostasis after plaque disruption, thrombolysis, or PTCA represents a strong rationale for the use of antithrombotic drugs. The results of the ISIS-2 trial and the data from the Antiplatelet Trialists' Collaboration indicated that aspirin is mandatory in patients with acute myocardial infarction and for secondary prevention. Recently, the efficacy of abciximab and other glycoprotein IIb/IIIa inhibitors was proven in the treatment of acute coronary syndromes and after PTCA, and their early use in patients with acute myocardial infarction is presently under evaluation. Anticoagulation with heparin appears to be only slightly effective in acute myocardial infarction not treated with thrombolysis; however, a rationale exists for its use in patients undergoing percutaneous and/or surgical revascularization and in conjunction with fibrin-specific thrombolytic agents. Further studies are under way on the possible usefulness of low-molecular-weight heparin. Direct antithrombin agents (hirudin, hirulog, and others) have been recently studied as an adjunct to thrombolysis. The data from these studies indicate the presence of a narrow therapeutic window, with only marginal advantage over heparin; studies with newer compounds are ongoing. Aspirin is still a mandatory drug in patients with acute myocardial infarction; the most promising agents in this setting seem to be glycoprotein IIb/IIIa inhibitors. Heparin and low-molecular-weight heparins are indicated in selected cases, and further studies are needed to assess the value of newer direct thrombin inhibitors.

Long-term (three-year) prognosis of patients treated with reperfusion or conservatively after acute myocardial infarction. Israeli Thrombolytic Survey Group

OBJECTIVES

This survey sought to assess the frequency of the use of thrombolytic therapy, invasive coronary procedures (ICP) (angiography, percutaneous transluminal coronary angioplasty and coronary artery bypass grafting [CABG]), variables associated with their use, and their impact on early (30-day) and long-term (3-year) mortality after acute myocardial infarction (AMI).

BACKGROUND

Few data are available regarding the implementation in daily practice of the results of clinical trials of treatments for AMI and their impact on early and long-term prognosis in unselected patients after AMI.

METHODS

A prospective community-based national survey was conducted during January-February 1994 in all 25 coronary care units operating in Israel.

RESULTS

Among 999 consecutive patients with an AMI (72% men; mean age 63+/-12 years) acute reperfusion therapy (ART) was used in 455 patients (46%; thrombolysis in 435 patients [44%] and primary angioplasty in 20 [2%]). Its use was independently associated with anterior AMI location and hospitals with on-site angioplasty facilities, whereas advancing age, prior myocardial infarction (MI) and prior angioplasty or CABG were independently associated with its lower use. The three-year mortality of patients treated with ART was lower than in counterpart patients (22.0% vs. 31.4%, p = 0.0008), mainly as the result of 30-day to 3-year outcome (12.4% vs. 21.1%; hazard ratio = 0.73, 95% confidence interval [CI] 0.52 to 1.03). Independent predictors of long-term mortality were: age, heart failure on admission or during the hospitalization, ventricular tachycardia or fibrillation and diabetes. The outcome of patients not treated with ART differed according to the reason for the exclusion, where patients with contraindications experienced the highest three-year (50%) mortality rate. After ART, coronary angiography, angioplasty and CABG were performed in-hospital in 28%, 12% and 5% of patients, respectively. Their use was independently associated with recurrent infarction or ischemia, on-site catheterization or CABG facilities, non-Q-wave AMI and anterior infarct location. In the entire study population, and in patients with a non-Q-wave AMI, performance of ICP was associated with lower 30-day mortality (odds ratio [OR] = 0.53, 95% CI 0.25 to 0.98, and OR = 0.21, 0.03 to 0.84, respectively), but not thereafter.

CONCLUSIONS

This survey demonstrates the extent of implementation in daily practice of ART and ICP and their impact on early and long-term prognosis in an unselected population after AMI.

Survival 12 years after randomization to streptokinase: the influence of thrombolysis in myocardial infarction flow at three to four weeks

OBJECTIVES

The purpose of this study was to determine whether the mortality benefit of intravenous streptokinase administered within 4 h of the onset of acute myocardial infarction is maintained at 12 years, and whether Thrombolysis in Myocardial Infarction (TIMI) flow grades independently influence late survival.

BACKGROUND

Treatment with reperfusion therapies and achievement of TIMI 3 flow are associated with increased short- and medium-term survival after infarction. Whether infarct artery flow independently influences survival more than five years after infarction is unknown.

METHODS

The late survival of patients randomized to receive either streptokinase (1,500,000 IU over 30 to 60 min) or a matching placebo within 4 h of symptom onset in 1984-1986 was determined. Angiography was performed in surviving patients at three to four weeks, and TIMI flow grades were assessed blind to randomization and outcomes. The late vital status was determined in 99% of patients.

RESULTS

Patients randomized to receive streptokinase (n = 107) had improved survival compared with those randomized to placebo (n = 112) at five years (84% vs. 70%; p = 0.023) and 12 years (66% vs. 51%; p = 0.022). At five years 94% of patients with TIMI grade 3 flow, 81% of those with TIMI grade 2 flow and 72% of those with TIMI grade 0-1 flow survived (p = 0.005). At 12 years 72% of patients with TIMI 3, 67% of those with TIMI 2 and 54% of those with TIMI 0-1 flow survived (p = 0.023). Multivariate analysis identified the ejection fraction (p = 0.014), exercise duration (p = 0.013) and TIMI 3 flow (p = 0.04 compared with TIMI 0-2 flow) as important factors for five-year survival. At 12 years multivariate predictors of late survival were the ejection fraction (p = 0.006), exercise duration (p = 0.003) and myocardial score (p = 0.013). The end-systolic volume index was similar to the ejection fraction as a predictor of survival at five and 12 years.

CONCLUSIONS

The survival benefits of streptokinase persist for 12 years after infarction. TIMI flow at three to four weeks is an independent predictor of five-year survival.

Relevance of clinical trial results in myocardial infarction to medical practice: comparison of four year outcome in participants of a thrombolytic trial, patients receiving routine thrombolysis, and those deemed ineligible for thrombolysis

OBJECTIVE

To assess the medium to long term outcome of patients ineligible for thrombolysis compared to those enrolled in a clinical trial of thrombolysis and patients receiving non-trial thrombolysis.

DESIGN

Cohort study based on the Nottingham heart attack register.

SETTING

Two district general hospitals serving a defined urban/rural population.

SUBJECTS

All patients admitted with a confirmed acute myocardial infarction during 1992 categorised as either participants of a thrombolytic trial (group A, n = 140), receiving non-trial thrombolysis (group B, n = 329), or deemed ineligible for lytic treatment (group C, n = 431).

MAIN OUTCOME MEASURES

Background characteristics, inhospital treatment, patterns of follow up, referrals to cardiologists, revascularisation rates, and short and long term survival.

RESULTS

Clinical trial recruits were younger by almost 10 years, were less likely to have a previous history of myocardial infarction, and more likely to be in Killip class 1 on admission than those ineligible for thrombolysis. Cardiology follow up was mandatory for all surviving trial participants but 22% of patients in group B and 31% of patients in group C received no follow up, and during four years less than 50% ever saw a cardiologist. Revascularisation was performed in 17.2% of patients in group A, 13.6% of patients in group B, and 7.5% of patients in group C. Cumulative mortality at a median of four years was 24.3% in group A, 36.8% in B, and 59.6% in group C. Adjusting for age, sex, previous myocardial infarction, type of infarction, and Killip class in a logistic regression model the odds ratios (OR) of death at four years for groups B and C were 1.60 (95% confidence intervals (CI) 0.97 to 2.63, p = 0.065) and 2.64 (95% CI 1.61 to 4. 32, p < 0.001), respectively, when compared to group A (OR 1).

CONCLUSIONS

Patients enrolled into thrombolytic trials are at low risk. Patients deemed ineligible for thrombolysis are high risk, receive less surveillance, are less likely to be revascularised or receive trial proven treatments, have a poor long term outcome not entirely explained by increased age or severity of infarction, and deserve further evaluation.

Hospital mortality of acute myocardial infarction in the thrombolytic era

OBJECTIVE

To examine the management and outcome of an unselected consecutive series of patients admitted with acute myocardial infarction to a tertiary referral centre.

DESIGN

A historical cohort study over a three year period (1992-94) of consecutive unselected admissions with acute myocardial infarction identified using the HIPE (hospital inpatient enquiry) database and validated according to MONICA criteria for definite or probable acute myocardial infarction.

SETTING

University teaching hospital and cardiac tertiary referral centre.

RESULTS

1059 patients were included. Mean age was 67 years; 60% were male and 40% female. Rates of coronary care unit (CCU) admission, thrombolysis, and predischarge angiography were 70%, 28%, and 32%, respectively. Overall in-hospital mortality was 18%. Independent predictors of hospital mortality by multivariate analysis were age, left ventricular failure, ventricular arrhythmias, cardiogenic shock, management outside CCU, and reinfarction. Hospital mortality in a small cohort from a non-tertiary referral centre was 14%, a difference largely explained by the lower mean age of these patients (64 years). Five year survival in the cohort was 50%. Only age and left ventricular failure were independent predictors of mortality at follow up.

CONCLUSIONS

In unselected consecutive patients the hospital mortality of acute myocardial infarction remains high (18%). Age and the occurrence of left ventricular failure are major determinants of short and long term mortality after acute myocardial infarction.

Usefulness of the presenting electrocardiogram in predicting successful reperfusion with streptokinase in acute myocardial infarction

The presenting electrocardiogram may contain information indicating the probability of successful reperfusion. The relation between 3 parameters in the presenting electrocardiogram (pathologic Q waves, T-wave inversion, and the slope of ST elevation) and Thrombolysis in Myocardial Infarction trial (TIMI) grade 3 flow in the infarct-related artery was assessed angiographically 90 minutes after beginning streptokinase in 362 patients. TIMI grade 3 flow was more common in patients without Q waves (55%) than in those with Q waves (35%; p <0.001), and more common in patients without T-wave inversion (50%) than in those with T-wave inversion (30%; p <0.002). There was no relation between the slope of the ST segment or the magnitude of its deviation and the achievement of TIMI grade 3 flow. Only 20% of the 59 patients with both Q waves and T-wave inversion had TIMI grade 3 flow, compared with 50% of the remaining patients (p <0.0001). Among patients treated within 3 hours, TIMI grade 3 flow was seen in 68% of those without versus 44% of those with Q waves (p <0.01), and in 62% of those without versus 43% of those with T-wave inversion (p = 0.06). Among patients treated after 3 hours, TIMI grade 3 flow was seen in 38% of those without versus 30% of those with Q waves (p = NS), and in 38% of those without versus 23% of those with T-wave inversion (p <0.05). On multivariate analysis, the absence of Q waves, the time from the onset of chest pain to treatment, and age were independent predictors of TIMI grade 3 flow. Pathologic Q waves in the presenting electrocardiogram provide valuable information as to the probability of achieving successful reperfusion following administration of streptokinase, and may be helpful for triage of patients to alternative reperfusion strategies, including percutaneous revascularization.

Effects of early captopril administration after thrombolysis on regional wall motion in relation to infarct artery blood flow

OBJECTIVES

To determine whether early administration of captopril lessens infarct zone regional wall motion abnormalities when infarct artery blood flow is abnormal.

BACKGROUND

The interaction between angiotensin-converting enzyme (ACE) inhibitor therapy, ventricular function and infarct artery blood flow has not been well described.

METHODS

A total of 493 patients aged < or = 75 years with first infarctions, presenting within 4 h of symptom onset, were randomized to receive 6.25 mg captopril, increasing to 50 mg t.d.s. or a matching placebo 2.1+/-0.4 h after commencing intravenous streptokinase (1.5 x 10(6) U over 30 to 60 min). Trial therapy was stopped 48 h prior to angiography at 3 weeks, to determine regional wall motion and infarct artery flow.

RESULTS

There were no differences in ejection fractions or end-systolic volumes between patients randomized to receive captopril and those randomized to receive a placebo. Among patients with anterior infarction (n = 216), randomization to captopril resulted in fewer hypokinetic chords (40+/-13; vs. 44+/-13; p=0.028) and a trend toward fewer chords >2 SD below normal (26+/-17 vs. 30+/-17; p=0.052) in the infarct zone. In patients randomized to receive captopril who had anterior infarction and Thrombolysis in Myocardial Infarction (TIMI) 0-2, flow there were fewer hypokinetic chords (44+/-12 vs. 50+/-9; p=0.043) and a trend toward fewer chords >2 SD below normal (33+/-15 vs. 39+/-13; p=0.057). Patients receiving captopril who had anterior infarction and corrected TIMI frame counts > 27 had fewer hypokinetic chords (42+/-13 vs. 46+/-12; p=0.015) and fewer chords >2 SD below normal (27+/-17 vs. 32+/-17; p= 0.047). Captopril had no effect in patients with inferior infarction. There were 20 late cardiac deaths (median follow-up 4 years) in the captopril group and 35 in the placebo group (p=0.036).

CONCLUSIONS

Randomization to receive captopril 2 h after streptokinase improved regional wall motion at 3 weeks. The greatest benefit was seen in patients with anterior infarction particularly when infarct artery blood flow is reduced.

The effect of reduction of door-to-needle times on the administration of thrombolytic therapy for acute myocardial infarction

Optimal management of acute myocardial infarction requires rapid administration of thrombolytic therapy. However, only patients who fulfill the following specific criteria are likely to benefit from this treatment: admission within 12 hours of the onset of symptoms, no contraindications, ST elevation or possible new-onset left bundle branch block on the admission electrocardiogram. We employed an aggressive policy to reduce the delay between admission to hospital and the administration of thrombolysis (the 'door-to-needle time'), and investigated whether this approach affected the accuracy of administration of thrombolysis. Patients admitted to the cardiac care unit with acute myocardial infarction, or who were thrombolysed, were identified retrospectively over two equivalent 4-month periods before and after implementation of our policy. Patients were considered eligible for thrombolysis if they fulfilled the criteria mentioned above. The mean (SD) door-to-needle time for all patients who received thrombolysis on admission decreased from 61(70) to 19(20) minutes (p = 0.0004). The proportion of patients eligible for thrombolysis who received treatment increased from 24/38 to 30/30 (p = 0.0002). However, the proportion of patients receiving thrombolysis who did not fulfill our criteria also increased, from 3/27 to 11/41 (p = 0.1). There were no complications of thrombolysis in the first study period, but two cerebrovascular accidents in the second period; both patients fulfiled our criteria for treatment. We conclude that simple educational measures greatly reduced door-to-needle times and led to a higher proportion of eligible patients receiving thrombolysis. However, greater pressure on medical staff to make rapid management decisions increased the proportion of patients being thrombolysed inappropriately.