One-year results from the Global Utilization of Streptokinase and TPA for Occluded Coronary Arteries (GUSTO-I) trial. GUSTO-I Investigators

Bleeding and Ischemic Risk Prediction in Patients With High Bleeding Risk (an EVOLVE Short DAPT Analysis)

The EVOLVE Short DAPT study demonstrated the safety of truncated dual antiplatelet therapy (DAPT) in patients with a high bleeding risk (HBR) treated with SYNERGY stent(s) (Boston Scientific Company, Marlborough, Massachusetts). In this population, bleeding and ischemic risk prediction may further inform DAPT decisions. This post hoc analysis of the EVOLVE Short DAPT study identified predictors of ischemic and bleeding events up to 15 months using Cox proportional hazard models. The predicted probabilities of bleeding were calculated using the Breslow method. Of 2,009 enrolled patients, 96.9% of the patients met at least 1 HBR criteria. At 15 months, the cumulative incidences of bleeding and ischemic events were 6.3% and 6.0%, respectively. The risk of bleeding was increased in patients who received oral anticoagulants (hazard ratio [HR] 2.24, 95% confidence interval [CI] 1.50 to 3.36, p <0.001) or had peripheral vascular disease (HR 1.61, 95% CI 1.01 to 2.56, p = 0.045). The risk of ischemic events was increased in patients with diabetes (HR 1.86, 95% CI 1.24 to 2.78, p <0.01) or congestive heart failure (HR 2.06, 95% CI 1.39 to 3.04, p <0.001). Renal insufficiency/failure was associated with both endpoints. There was a strong positive correlation between the predicted probability of ischemic and bleeding events (R = 0.77, p <0.001). In 617 patients with a predicted bleeding risk <4%, ischemic events predominated, and the ischemic and bleeding rates were higher in patients with a predicted bleeding risk ≥4%. Within an HBR cohort, specific characteristics identify patients at a higher risk for ischemic and separately, bleeding events. Increased bleeding risk is tied to increased ischemic risk. In conclusion, standardized risk models are needed to inform DAPT decisions in patients with a higher risk. Clinical Trial Registration: NCT02605447.

Primary Percutaneous Coronary Intervention and Application of the Pharmacoinvasive Approach Within ST-Elevation Myocardial Infarction Care Networks

The management of acute ST-elevation myocardial infarction (STEMI) has transitioned from observation and reactive treatment of hemodynamic and arrhythmic complications to accelerated reperfusion and application of evidence-based treatment to minimize morbidity and mortality. International research established the importance of timely reperfusion therapy and the application of fibrinolysis, primary percutaneous coronary intervention (PCI), and subsequent development of the pharmacoinvasive approach. Clinician thought leaders developed and investigated comprehensive systems of care to optimize the outcomes of patients with STEMI, with a key focus in Canada being the integration of prehospital paramedics in diagnosis, triage, and treatment. This article will review highlights of these interventions and identify future challenges and opportunities in STEMI patient care.

One-year outcome and survival analysis of deferred ventricular septal repair in cardiogenic shock supported with mechanical circulatory support

Background and objective

The effectiveness of deferred surgical repair of ventricular septal rupture (VSR) post-myocardial infarction (MI) with cardiogenic shock remains limited to case reports. Our study aimed to investigate the outcomes and survival analysis following mechanical circulatory support (MCS) in patients after VSR who develop cardiogenic shock.

Methods

We analyzed 27 patients with post-MI VSR and cardiogenic shock who received deferred surgical repair while stabilized on MCS between January 2018 and March 2020. After normality test adjustments, continuous variables were expressed as mean ± standard deviation (SD). These were compared using the Mann-Whitney U test and Student’s t-test. Categorical variables were compared using chi-square or Fisher’s exact test. To identify predictors of operative mortality, univariate analysis of clinical characteristics and interventions followed by logistic regression was carried out. P-value of < 0.05 was considered significant.

Results

All patients had preoperative MCS. Emergency repair was avoided in all the patients. The mean age of the participants was 64.96 with the majority being males (74.1%). On average, the mean time from MI to VSR repair was 18.85 days. Delayed revascularization was associated with increased mortality (OR 17.500, 95% CI 2.365–129.506, P = 0.005). Other factors associated with increased mortality were ejection fraction (EF), three-vessel disease, Killip class, early surgery, and prolonged use of inotropes. The operative mortality was 11% with an overall mortality of 33.3%. The one-year survival rate was 66.7%.

Conclusion

The use of MCS in adjunct to a deferred surgical approach shows an improved survival outcome of patients with VSR complicated by cardiogenic shock. Further investigations are required regarding the optimal time for MCS and surgical repair.

Salvage use of tissue plasminogen activator (tPA) in the setting of acute respiratory distress syndrome (ARDS) due to COVID-19 in the USA: a Markov decision analysis

Background

COVID-19 threatens to quickly overwhelm our existing critical care infrastructure in the USA. Systemic tissue plasminogen activator (tPA) has been previously demonstrated to improve PaO₂/FiO₂ (mmHg) when given to critically ill patients with acute respiratory distress syndrome (ARDS). It is unclear to what extent tPA may impact population-based survival during the current US COVID-19 pandemic.

Methods

A decision analytic Markov state transition model was created to simulate the life critically ill COVID-19 patients as they transitioned to either recovery or death. Two patient groups were simulated (50,000 patients in each group); (1) Patients received tPA immediately upon diagnosis of ARDS and (2) patients received standard therapy for ARDS. Base case critically ill COVID-19 patients were defined as having a refractory PaO₂/FiO₂ of < 60 mmHg (salvage use criteria). Transition from severe to moderate to mild ARDS, recovery, and death were estimated. Markov model parameters were extracted from existing ARDS/COVID-19 literature.

Results

The use of tPA was associated with reduced mortality (47.6% [tTPA] vs. 71.0% [no tPA]) for base case patients. When extrapolated to the projected COVID-19 eligible for salvage use tPA in the USA, peak mortality (deaths/100,000 patients) was reduced for both optimal social distancing (70.5 [tPA] vs. 75.0 [no tPA]) and no social distancing (158.7 [tPA] vs. 168.8 [no tPA]) scenarios.

Conclusions

Salvage use of tPA may improve recovery of ARDS patients, thereby reducing COVID-19-related mortality and ensuring sufficient resources to manage this pandemic.

Observational study comparing pharmacoinvasive strategy with primary percutaneous coronary intervention in patients presenting with ST elevation myocardial infarction to a tertiary care centre in India

Objective:

The objective was to study whether the incidence of composite end points (mortality, cardiogenic shock and re-myocardial infarction [re-MI]) in pharmacoinvasive strategy was noninferior to primary percutaneous coronary intervention (PCI) in patients with ST-elevation myocardial infarction (STEMI).

Methods:

This was an observational study which included 138 patients. The study included patients admitted with a diagnosis of STEMI within 24 h of symptom onset, who underwent primary PCI or pharmacoinvasive therapy in a single center over a 9-month period. Primary end points (death within 30 days, re-MI within 30 days, and cardiogenic shock) and secondary end points (arrhythmias, bleeding manifestations, ischemic stroke, ejection fraction, mechanical complications, and duration of hospital stay) were compared between the two groups at 1 month after intervention.

Results:

At one month follow-up, the incidence rate for primary end points was 5 events per 43 patients (11.6%) in pharmacoinvasive arm and 18 events per 95 patients (18.9%) in primary PCI arm, a difference of - 7.3% (95% confidence interval: 18.5, 7.1). This finding shows that pharmacoinvasive strategy as compared with primary PCI in the management of STEMI was equivalent in terms of composite primary outcome. There was no significant difference between the secondary outcomes between the two groups. Use of thrombus aspiration device and in turn the thrombus burden was significantly lower in the pharmacoinvasive arm.

Conclusion:

This observational study showed that pharmacoinvasive strategy was as good as primary PCI in STEMI, in our setting, where primary PCI may be delayed or not possible at all due to financial and logistic constraints.

A seven-center examination of the relationship between monthly volume and mortality in trauma: a hypothesis-generating study

INTRODUCTION

The relationship between trauma volumes and patient outcomes continues to be controversial, with limited data available regarding the effect of month-to-month trauma volume variability on clinical results. This study examines the relationship between monthly trauma volume variations and patient mortality at seven Level I Trauma Centers located in the Eastern United States. We hypothesized that higher monthly trauma volumes may be associated with lower corresponding mortality.

METHODS

Monthly patient volume data were collected from seven Level I Trauma Centers. Additional information retrieved included monthly mortality, demographics, mean monthly injury severity (ISS), and trauma mechanism (blunt versus penetrating). Mortality was utilized as the primary study outcome. Statistical corrections for mean age, gender distribution, ISS, and mechanism of injury were made using analysis of co-variance (ANCOVA). Center-specific, annually-adjusted median monthly volumes (CSAA-MMV) were calculated to standardize patient volume differences across participating institutions. Statistical significance was set at α < 0.05.

RESULTS

A total of 604 months of trauma admissions, encompassing 122,197 patients, were analyzed. Controlling for patient age, gender, ISS, and mechanism of injury, aggregate data suggested that monthly trauma volumes < 100 were associated with significantly greater mortality (3.9%) than months with volumes > 400 (mortality 2.9%, p < 0.01). To account for differences in monthly volumes between centers, as well as for temporal bias associated with potential differences over the entire study duration period, data were normalized using CSAA-MMV as a standardized reference point. Monthly volumes ≤ 33% of the CSAA-MMV were associated with adjusted mortality of 5.0% whereas monthly volumes ≥ 134% CSAA-MMV were associated with adjusted mortality of 2.7% (p < 0.01).

CONCLUSIONS

This hypothesis-generating study suggests that greater monthly trauma volumes appear to be associated with lower mortality. In addition, our data also suggest that across all participating centers mortality may be a function of relative month-to-month volume variation. When normalized to institution-specific, annually-adjusted "median" monthly trauma contacts, we show that months with patient volumes ≤ 33% median may be associated with subtly but not negligibly (1.4-2.3%) higher mortality than months with patient volumes ≥ 134% median.

The impact of systems-of-care on pharmacoinvasive management with streptokinase: The subgroup analysis of the TN-STEMI programme

Objectives

We evaluated the impact of implementation of the TN-STEMI programme on various characteristics of the pharmacoinvasive group by comparing clinical as well as angiographic outcomes between the pre- and post-implementation groups.

Methods

The TN-STEMI programme involved 2420 patients of which 423 patients had undergone a pharmacoinvasive strategy of reperfusion. Of these, 407 patients had a comprehensive blinded core-lab evaluation of their angiograms post-lysis and clinical evaluation of various parameters including time-delays and adverse cardio- and cerebro-vascular events at 1 year. Streptokinase was used as the thrombolytic agent in 94.6% of the patients.

Results

In the post-implementation phase, there was a significant improvement in ‘First medical contact (FMC)-to-ECG’ (11 vs. 5 min, p < 0.001) and ‘Lysis-to-angiogram’ (98.3 vs. 18.2 h, p < 0.001) times. There was also a significant improvement in the number of coronary angiograms performed within 24 h (20.7% vs. 69.3%, p < 0.001). The ‘Time-to-FMC’ (160 vs. 135 min, p = 0.07) and ‘Total ischemic time’ (210 vs. 176 min, p = 0.22) also showed a decreasing trend. IRA patency rate (70.2% vs. 86%, p < 0.001) and thrombus burden (TIMI grade 0: 49.1% vs. 73.4%, p < 0.001) were superior in this group. The MACCE rates were similar except for fewer readmissions (29.8% vs. 12.6%, p = 0.0002) and target revascularizations at 1 year (4.8% vs. none, p = 0.002) in the post-implementation group.

Conclusion

The implementation of a system-of-care (hub-and-spoke model) in the pharmacoinvasive group of the TN-STEMI programme demonstrated shorter lysis-to-angiogram times, better TIMI flow patterns and lower thrombus burden in the post-implementation phase.

Ventricular Arrhythmia after Acute Myocardial Infarction: 'The Perfect Storm'

Ventricular tachyarrhythmias (VAs) commonly occur early in ischaemia, and remain a common cause of sudden death in acute MI. The thrombolysis and primary percutaneous coronary intervention era has resulted in the modification of the natural history of an infarct and subsequent VA. Presence of VA could independently influence mortality in patients recovering from MI. Appropriate risk assessment and subsequent treatment is warranted in these patients. The prevention and treatment of haemodynamically significant VA in the post-infarct period and of sudden cardiac death remote from the event remain areas of ongoing study.

Assessing quality-of-life outcomes in cardiovascular clinical research

The field of quality-of-life (QOL) measurement grew out of attempts in the 1960s and 1970s to connect the ever-increasing levels of public expenditure on technology-based health care for chronic diseases with evidence of the benefits and harms to patients. Most of the concepts, methods, and standards for measuring QOL were derived from psychometrics, but the degree to which current tools adhere to these methods varies greatly. Despite the importance of QOL, patient-reported outcomes are not measured in most cardiovascular clinical trials. Lack of familiarity with QOL measures and their interpretation, and unrealistic expectations about the information these measures can provide, are obstacles to their use. Large clinical trials of revascularization therapy for coronary artery disease and medical treatments for heart failure show small-to-moderate QOL effects, primarily detected with disease-specific instruments. Larger treatment effects, seen in trials of device therapy for heart failure and ablation therapy for atrial fibrillation, have been detected with both generic and disease-specific instruments. A large gap remains between the parameters currently being measured in clinical research and the data needed to incorporate the 'patient's voice' into therapeutic decision-making.

Systemic inflammatory response syndrome following catheter-directed thrombolysis of acute iliofemoral deep venous thrombosis

Catheter-directed thrombolysis is becoming increasingly considered in the treatment of acute ileofemoral deep vein thrombosis. By targeting occlusive thrombi early, it is possible to mitigate the symptoms of post-thrombotic syndrome, which include oedema, pain, and ulceration. NICE guidelines recommend the use of catheter-directed thrombolysis in those without contraindications to treatment. The main risk of thrombolysis is bleeding; however, other side effects such as allergy have been reported. We present a 50-year-old man who presented with an acute left-sided ileofemoral deep vein thrombosis. He underwent catheter-directed thrombolysis in our centre to good effect, and ultimately he required stenting due to the presence of a May-Thurner lesion. His first day of thrombolysis, however, was complicated by a massive systemic inflammatory response syndrome response resulting in pyrexia and tachycardia, rigors, and myalgia. His deterioration in observations corresponded with a huge rise in D-dimer levels from an admission baseline of 1465 ng/ml to 182,835 ng/ml. We hypothesize that rapid breakdown of thrombus in this patient resulted in a lysis-type syndrome, presenting with a systemic inflammatory response syndrome response. Several questions are raised here including why the patient responded in this way, and whether there could be a way to predict response ahead of time? Fortunately, our patient came to no harm and continues to do well, with no evidence of further thrombosis on surveillance ultrasound. This case highlights an important complication of thrombolysis and reminds us that complications are not just limited to bleeding. Despite the short-term effects in this young fit patient, concerns must be raised about potential safety in the frailer and more elderly patient demographic in which such a large inflammatory response could be more detrimental.

Targeted introduction of tissue plasminogen activator (TPA) at the AAVS1 locus in mesenchymal stem cells (MSCs) and its stable and effective expression

Thrombolytic therapy using tissue plasminogen activator (TPA) is an effective method for treating acute myocardial infarction. However, the systemic administration of TPA is associated with the risk of hemorrhage. Mesenchymal stem cells (MSCs) from bone marrow are characterized by low immunogenicity and homing toward damaged tissues and are therefore ideal cell carriers to achieve lesion-targeting medication. In this article, TPA gene was integrated into the AAVS1 of mesenchymal stem cells, which has been confirmed to be a safe chromosomal locus. The targeting efficiency was 83%. The clones with the site-specific integration retained the stem cell traits of MSCs, displayed a normal karyotype and could persistently and effectively express TPA, as demonstrated by an average expression activity of 1.5 units/mL (3.4-fold that of the control group). After subculture and subsequent growth for two weeks, the clones showed an average TPA activity of 1.43 units/mL and exhibited no significant differences among the individual clones. In summary, the foreign TPA gene can be specifically introduced to the AAVS1 locus, whereby it can be stably and effectively expressed. MSCs can serve as cell carriers for the targeted treatment of a thrombus using TPA.

The electrocardiographic reperfusion peak in patients with ST-elevation myocardial infarction

OBJECTIVES

To analyse the incidence and the prognostic value of the reperfusion peak in a population of patients with AMI treated with thrombolysis.

DESIGN

Two hundred and sixty-nine patients with ST-elevation myocardial infarction treated with thrombolysis were monitored with continuous on-line vectorcardiography.

RESULTS

A reperfusion peak defined as a transiently increased ST-VM of >50 microV followed by an immediate decrease to a level lower than the starting point was seen in 112 of all 269 (42%) patients and in 111 of 149 (75%) of the patients with successful ST-resolution. A reperfusion peak was an independent predictor of better prognosis both in the short- and the long term but had no implications on the prognosis in the subgroup with successful ST-resolution.

CONCLUSION

A reperfusion peak was equally common in patients treated with thrombolysis having a successful ST-resolution as observed in studies of patients with successful primary coronary angioplasty. The reperfusion peak was associated with better prognosis and should be recognised as a possible marker of successful reperfusion but can mimic aggravated ischemia.

C-terminal provasopressin (copeptin) is associated with left ventricular dysfunction, remodeling, and clinical heart failure in survivors of myocardial infarction

BACKGROUND

Acute myocardial infarction (AMI) is associated with left ventricular (LV) dysfunction and clinical heart failure. Arginine vasopressin is elevated in heart failure and the C-terminal of provasopressin (Copeptin) is associated with adverse outcome post-AMI. The aim of this study was to describe the association between Copeptin with LV dysfunction, volumes, and remodeling and clinical heart failure post-AMI.

METHODS AND RESULTS

We studied 274 subjects with AMI. Copeptin was measured from plasma at discharge and subjects underwent echocardiography at discharge and follow-up (median 155 days). Subjects were followed for clinical heart failure for a median of 381 days. Remodeling was assessed as the change (Delta) in LV volumes between echo examinations. Copeptin correlated directly with wall motion index score (WMIS) and inversely with LV ejection fraction (LVEF) at discharge (WMIS, r=0.276, P < .001; LVEF, r=-0.188, P=.03) and follow-up (WMIS, r=0.244, P < .001; LVEF, r=-0.270, P < .001) and with ventricular volumes at follow-up (LVEDV, r=0.215, P=.002; LVESV, r=0.299, P < .001). Copeptin was associated with ventricular remodeling; DeltaEDV; r=0.171, P=0.015, DeltaESV; r=0.186, P=.008. Subjects with increasing LVESV had higher levels of Copeptin (median 6.30 vs. 5.75 pmol/L, P=.012). Subjects with clinical heart failure (n=30) during follow-up had higher Copeptin before discharge (median 13.55 vs. 5.80, P < .001). In a Cox proportional hazards model, Copeptin retained association with clinical heart failure. Kaplan-Meier assessment revealed increased risk in subjects with Copeptin >6.31 pmol/L.

CONCLUSIONS

Copeptin is associated with LV dysfunction, volumes, and remodeling and clinical heart failure post-AMI. Measurement of Copeptin may provide prognostic information and the AVP system may be a therapeutic target in post-MI LV dysfunction.

Home use of automated external defibrillators for sudden cardiac arrest

BACKGROUND

The most common location of out-of-hospital sudden cardiac arrest is the home, a situation in which emergency medical services are challenged to provide timely care. Consequently, home use of an automated external defibrillator (AED) might offer an opportunity to improve survival for patients at risk.

METHODS

We randomly assigned 7001 patients with previous anterior-wall myocardial infarction who were not candidates for an implantable cardioverter-defibrillator to receive one of two responses to sudden cardiac arrest occurring at home: either the control response (calling emergency medical services and performing cardiopulmonary resuscitation [CPR]) or the use of an AED, followed by calling emergency medical services and performing CPR. The primary outcome was death from any cause.

RESULTS

The median age of the patients was 62 years; 17% were women. The median follow-up was 37.3 months. Overall, 450 patients died: 228 of 3506 patients (6.5%) in the control group and 222 of 3495 patients (6.4%) in the AED group (hazard ratio, 0.97; 95% confidence interval, 0.81 to 1.17; P=0.77). Mortality did not differ significantly in major prespecified subgroups. Only 160 deaths (35.6%) were considered to be from sudden cardiac arrest from tachyarrhythmia. Of these deaths, 117 occurred at home; 58 at-home events were witnessed. AEDs were used in 32 patients. Of these patients, 14 received an appropriate shock, and 4 survived to hospital discharge. There were no documented inappropriate shocks.

CONCLUSIONS

For survivors of anterior-wall myocardial infarction who were not candidates for implantation of a cardioverter-defibrillator, access to a home AED did not significantly improve overall survival, as compared with reliance on conventional resuscitation methods. (ClinicalTrials.gov number, NCT00047411 [ClinicalTrials.gov].).

Rationale and design of the Home Automatic External Defibrillator Trial (HAT)

Most cardiac arrests occur in the home, where emergency medical services (EMS) systems are challenged to provide timely care. Because a large proportion of sudden cardiac arrests (SCAs) are due to ventricular tachycardia or ventricular fibrillation, home use of an automated external defibrillator (AED) might offer an opportunity to decrease mortality in those at risk. Predicting who will have a cardiac arrest in the general population is difficult. Individuals at high risk are usually easily identified and may become candidates for implantable cardioverter defibrillators. It is within the population at lower risk where home AEDs may be most useful. The purpose of the Home Automatic External Defibrillator Trial (HAT) is to test whether providing home access to an AED can improve survival in patients at modest risk of SCA, such as those surviving an anterior myocardial infarction but in whom implantable cardioverter defibrillator therapy is not deemed necessary. Between January 23, 2003, and October 20, 2005, 7001 patients were enrolled, with completion of follow-up scheduled for September 30, 2007. Randomization was conducted in a 1:1 fashion between control therapy, comprising the standard lay response to SCA (calling the EMS and performing cardiopulmonary resuscitation), and the use of an AED first, followed by calling the EMS and performing cardiopulmonary resuscitation. The primary end point is all-cause mortality. Secondary outcomes include survival from SCA (witnessed and unwitnessed, in home and out of home), incremental cost-effectiveness, and quality of life measures for both the patient and the spouse/companion. The results of the trial should be available in mid 2008.

Cost-effectiveness of thrombolytics: a simplified model

OBJECTIVE OF THE STUDY

To construct a simple model for an internal, retrospective cost-effectiveness analysis and to calculate the incremental cost-effectiveness of tissue plasminogen activator (TPA) over streptokinase (SK) in Turkey.

SETTING

Koşuyolu Heart, Education and Research Hospital, Istanbul, Turkey.

METHOD

Among patients who were hospitalized for treatment of acute myocardial infarction (AMI), 196 were randomly selected. One-year mortality rates according to the treatment groups (TPA, SK, other) were determined. Among surviving patients, 28 from TPA and another 28 from SK group were randomly selected for the pharmacoeconomic analysis. Patient treatment data were taken from medical records while data regarding to costs were taken from hospital bills.

MAIN OUTCOME MEASURES

Incremental cost-effectiveness ratio (ICER). The cost part of the ratio was considered as 'the overall-costs', while the effectiveness part was considered as 'lives saved' per treatment group.

RESULTS

With an increased one-year survival rate of 2.37% and an increased cost of euro 1120.8 ($1165.6) per patient in the TPA group, the ICER for the use of TPA instead of SK was euro 47,289 ($49,180.6) per life saved.

CONCLUSION

This model can be a guide for similar analyses. The results of our study (the incremental cost-effectiveness of TPA over SK) will be informative for the decision-makers in Turkey, by whom the medical benefit for money spent would be assessed and judged. We believe that our results make a contribution to similar studies in the literature.

Effect of tissue plasminogen activator on vascular smooth muscle cells

OBJECTIVE

Engineered overexpression of tissue plasminogen activator (tPA) in vascular cells has been proposed as a means to decrease intravascular thrombosis; however, tPA gene transfer has augmented intimal hyperplasia in vivo in some studies. The purpose of this study was to define in vitro the effect of tPA gene transfer on smooth muscle cells (SMCs).

METHODS

Human SMCs were retrovirally transduced with the tPA gene (SMCs/tPA).

RESULTS

In the absence of plasminogen, no statistical differences in proliferation, migration, and morphology were observed between SMCs/tPA and SMCs. In the presence of plasminogen, many differences became apparent. Matrix metalloproteinase-2 (MMP-2) activation was 10-fold higher in SMCs/tPA than in SMCs. This activation was inhibited by aprotinin, a plasmin inhibitor. Collagen degradation increased sevenfold in SMCs/tPA. SMCs/tPA contracted dramatically in the presence of plasminogen. This cell contraction, indicative of extracellular matrix degradation, was blocked by aprotinin and partially inhibited by MMP inhibitors. SMC/tPA-conditioned medium induced significantly more SMC proliferation. The migration of SMCs/tPA through a porous membrane significantly exceeded untransduced SMCs.

CONCLUSIONS

Over-expression of tPA in SMCs results in increased extracellular matrix degradation and can promote cell proliferation and migration. This effect is mediated via plasmin, which further activates MMP-2.

CLINICAL RELEVANCE

TPA has been clinically used as a thrombolytic agent in the treatment of acute thrombotic disorders. Transferring the tPA gene into vascular cells as a strategy of gene therapy has been proposed to enhance fibrinolytic capability and therefore inhibit thrombosis and restenosis after vascular interventions. The mechanism(s) by which tPA affects SMC proliferation and vascular remodeling has not been thoroughly characterized. This study unveils the relationship between thrombolytic activity and intimal hyperplasia by showing how the elevated expression of tPA affects the vascular remodeling. This study underscores that the overexpression of an enzyme thought beneficial to blood flow can potentially compromise blood flow by altering the biology of the cell engineered to express it. The results are important to the rational engineering of bioactive grafts with better patency. A new strategy to enhance the thrombolytic ability of a vascular surface without inducing excessive neointimal hyperplasia is proposed.

Too little aspirin for secondary prevention after acute myocardial infarction in patients at high risk for cardiovascular events: Results from the MITRA study

BACKGROUND

A meta-analysis of randomized trials has shown a significant reduction of mortality rate in patients receiving aspirin for secondary prevention after acute myocardial infarction (AMI). However, a significant number of patients do not receive aspirin after AMI. Little is known about why aspirin is withheld or the long-term outcome of these patients today.

METHODS

The Maximal Individual Therapy in Acute Myocardial Infarction (MITRA) registry is a multicenter registry of patients with AMI in Germany.

RESULTS

Of 4902 patients, 509 (10%) did not receive aspirin at the time of discharge from the hospital. The mean follow-up period for these patients was 17 months. Relative contraindications to aspirin were significantly associated with the withholding of aspirin (in-hospital bleeding: odds ratio [OR], 3.56; 95% CI, 1.86-6.80; history of peptic ulcer: OR, 2.49; 95% CI, 1.62-3.83). Absolute contraindications to aspirin were rare (2.2%). Other medications of proven benefit were also given less often in these patients (beta-blockers: 49.0% vs 61.9%, P <.001; angiotensin-converting enzyme inhibitors: 65.6% vs 70.2%, P =.06; statins: 12.2% vs 15.1%, P =.10). Patients who were not given aspirin were at high risk for vascular events. They were more likely to have a history of prior AMI (OR, 1.34; 95% CI, 1.02-1.79), were in critical clinical condition at admission more often (cardiogenic shock: OR, 1.98; 95% CI, 1.09-3.56; overt heart failure: OR, 1.6; 95% CI, 1.05-2.3), and received acute revascularization less often (OR, 1.32; 95% CI, 1.05-1.67). The 1-year mortality was 2-times higher in patients who did not receive aspirin than in patients who did receive aspirin (16.5% vs 8.3%, P <.001). A significant association of withheld aspirin at discharge with a higher long-term mortality rate was confirmed with multivariate analysis (OR, 1.62; 95% CI, 1.15-2.29).

CONCLUSIONS

Ten percent of patients who sustained an AMI did not receive aspirin at the time of hospital discharge. Most of these patients were at high risk for cardiovascular events. Withheld aspirin was significantly associated with higher mortality rate during follow up.

Influence of acute resistance exercise on cardiac biomarkers in untrained women

This study was conducted to determine if an initial bout of resistance (weight lifting) exercise by untrained women results in any alterations in indicators of acute myocardial infarction (AMI). Untrained women performed 4 resistance exercises at 70% of their 1 repetition maximum. Blood samples were obtained during the 12 h post-exercise and analyzed for total creatine kinase (CK)-MB, CK-MB subforms 1 and 2, and the relative lymphocyte percentage. Exercise resulted in significant increases in total CK-MB, CK-MB(1), CK-MB(2), and the CK-MB(2)/CK-MB(1) ratio, total leukocyte count, and lymphocyte count. Using several criteria for the assessment of AMI, 22-25% of subjects completing the protocol demonstrated increases in CK-MB(2), CK-MB(2)/CK-MB(1) ratio, and relative lymphocyte percentages that were suggestive of AMI. Thus, our data suggest that moderate resistance exercise can significantly alter blood indicators of AMI, emphasizing the need to determine recent exercise history in patients with possible AMI.

One-year follow-up of the ASSENT-2 trial: a double-blind, randomized comparison of single-bolus tenecteplase and front-loaded alteplase in 16,949 patients with ST-elevation acute myocardial infarction

BACKGROUND

Single-bolus tenecteplase and accelerated alteplase were shown to be equivalent for 30-day mortality rates in the double-blind Assessment of the Safety of a New Thrombolytic (ASSENT-2) study. The aim of this study is to assess mortality rates after 1-year follow-up.

METHODS AND RESULTS

One-year vital status was obtained from 92.8% of the patients initially enrolled in the ASSENT-2 trial. Completeness of follow-up was similar for both groups. At 1 year, mortality rates were 9.1% for alteplase and 9.2% for tenecteplase (risk ratio, 1.01; 95% CI, 0.91-1.12). The mortality rate between 30 and 365 days after enrollment was 2.6% for alteplase and 2.8% for tenecteplase (risk, 1.07; 95% CI, 0.88-1.30). A lower 30-day mortality rate in patients treated with tenecteplase after 4 hours of symptom-onset persisted at 1-year follow-up (10.9% vs 12.6% for alteplase), but was no longer statistically significant. There were also no significant differences in mortality rates between the 2 treatments in other major subgroups. In a Cox regression model, no significant interaction was observed between treatment assignment and age, sex, time-to-treatment, Killip class, body weight, and history of previous myocardial infarction, infarction location, systolic blood pressure, or heart rate.

CONCLUSIONS

One year after randomization, mortality rates remain similar in patients with acute myocardial infarction treated with an accelerated infusion of alteplase or a single bolus of tenecteplase.

Clinical outcomes of patients with diabetes mellitus and acute myocardial infarction treated with primary angioplasty or fibrinolysis

OBJECTIVE

To compare the early and late outcomes of primary percutaneous transluminal coronary angioplasty (PTCA) with fibrinolytic treatment among diabetic patients with acute myocardial infarction (AMI).

DESIGN

Retrospective observational study with data obtained from prospective registries.

SETTING

Tertiary cardiovascular institution with 24 hour acute interventional facilities.

PATIENTS

202 consecutive diabetic patients with AMI receiving reperfusion treatment within six hours of symptom onset.

INTERVENTIONS

Fibrinolytic treatment was administered to 99 patients, and 103 patients underwent primary PTCA. Most patients undergoing PTCA received adjunctive stenting (94.2%) and glycoprotein IIb/IIIa inhibition (63.1%).

MAIN OUTCOME MEASURES

Death, non-fatal reinfarction, and target vessel revascularisation at 30 days and one year were assessed.

RESULTS

Baseline characteristics were similar in these two treatment groups except that the proportion of patients with Killip class III or IV was considerably higher in those treated with PTCA (15.5% v 6.1%, p = 0.03) and time to treatment was significantly longer (103.7 v 68.0 minutes, p < 0.001). Among those treated with PTCA, the rates for in-hospital recurrent ischaemia (5.8% v 17.2%, p = 0.011) and target vessel revascularisation at one year (19.4% v 36.4%, p = 0.007) were lower. Death or reinfarction at one year was also reduced among those treated with PTCA (17.5% v 31.3%, p = 0.02), with an adjusted relative risk of 0.29 (95% confidence interval 0.15 to 0.57) compared with fibrinolysis.

CONCLUSION

Among diabetic patients with AMI, primary PTCA was associated with reduced early and late adverse events compared with fibrinolytic treatment.

Endothelial inflammation and thrombolysis resistance in acute myocardial infarction

BACKGROUND

Despite recent refinements to thrombolysis for acute myocardial infarction, a significant minority of patients still fail to reperfuse. There is no reliable predictor of this state of "thrombolysis resistance", but platelet and endothelial factors are believed to be important. Cell adhesion molecules are expressed by the endothelium when activated and their shed or soluble portion can be quantified in the peripheral serum, where they may be taken as a measure of endothelial activation. We sought to find a link between markers of endothelial inflammation at time of infarction and failure to reperfuse as measured by vessel occlusion at angiography.

METHODS

Patients presenting with their first acute myocardial infarction had levels of soluble adhesion molecules, C-reactive protein and monocyte chemotactic protein-1 measured prior to thrombolysis. An angiogram on day five after admission was performed to establish patency of the index vessel.

RESULTS

Levels of soluble vascular adhesion molecule-1 (sVCAM-1) taken prethrombolysis were significantly elevated compared to those with a patent vessel (620+/-90 vs. 418+/-28 ng/ml, P<0.03. The positive predictive value of sVCAM-1 for vessel patency was 88%.

CONCLUSIONS

We found elevated serum levels of the adhesion molecule soluble vascular adhesion molecule-1 (sVCAM-1) at presentation in patients with acute myocardial infarction who did not respond to thrombolysis. Endothelial activation may be important in thrombolysis resistance.

Microsurgical repair after crush-avulsion injury of the femoral vein in rats: prevention of microvascular thrombosis with recombinant human tissue-type plasminogen activator (rt-PA)

Vein thrombosis is often encountered in microsurgery, especially in the case of crush-avulsion injuries. The aim of this study was to investigate the effect of systemic administration of recombinant tissue-type plasminogen activator (rt-PA) on the patency of the femoral vein of the rat, which had previously sustained a crush-avulsion injury. The study consisted of 3 groups of male Wistar rats, 20 animals each. A standardized crush-avulsion injury model was used. After microvascular repair of the femoral vein, the animals received either normal saline (group A), heparin 100 U/kg body weight (group B), or rt-PA 3.5 mg/kg body weight (group C) systemically. Patency tests were performed at 20 minutes, 48 hours, and 1 week after blood flow reestablishment. According to our results, the patency rate of the rt-PA group was significantly higher than in both the control and heparin groups.

Enhancement of neointima formation with tissue-type plasminogen activator

PURPOSE

Indirect evidence suggests that tissue plasminogen activator (tPA) either limits or does not alter restenosis. However, tPA enhances tumor invasiveness through matrix remodeling, and several elements of degraded matrix enhance smooth muscle cell mitogenesis. We use either local adenoviral-mediated overexpression of tPA or systemic infusion of recombinant tPA combined with mechanical overdilation of rabbit common femoral arteries to evaluate the impact of tPA on neointima formation.

METHODS

Left common femoral arteries of New Zealand white rabbits were transfected in situ either with an adenoviral-construct-expressing tPA or a viral control (adenoviral-construct-expressing beta-galactosidase) or nonviral (buffer) control after balloon angioplasty injury. At 7 and 28 days, left common femoral artery segments were harvested (n = 4 for each group and time point). Vessel segments were examined for intimato-media ratio, smooth muscle cell proliferation, extracellular matrix, and inflammatory response. Thrombus formation was evaluated after 3 days (n = 3 for each group). In a second experiment, New Zealand white rabbits (n = 3 per group, per time point) underwent mechanical dilation followed by buffer treatment or systemic tPA infusion according to a widely clinically used accelerated infusion protocol. Treated artery segments were harvested after 7 or 28 days and processed for intima-to-media ratio determination and class-wide histochemical determination of collagenous extracellular matrix and collagen content.

RESULTS

Both rate and degree of neointima formation increase dramatically with overexpression (250%-461% relative to controls at 7 and 28 days). Substantial early matrix degradation is observed in vessels treated with local overexpression of tPA, although no increases in local inflammation or in smooth muscle proliferation occur. Late enhancement of smooth muscle proliferation emerges, consistent with secondary impact of perturbed matrix components. Systemic infusion of tPA according to clinical protocols also results in early and late enhancement of neointima formation in this model (34%-52% relative to controls at at 7 and 28 days), with significant early collagenous matrix degradation. Systemic infusion, although significant, did not attain the degree of neointima formation present with overexpression.

CONCLUSION

With some evidence of dose-dependence, tissue plasminogen activator enhances neointima formation after angioplasty in a rabbit model. Early matrix degradation precedes change in rates of proliferation and underlies this effect in spite of several antirestenotic actions including decreased thrombus and decreased macrophage recruitment in this model.

The impact of time to thrombolytic treatment on outcome in patients with acute myocardial infarction. For the CORE investigators (Collaborative Organisation for RheothRx Evaluation)

OBJECTIVES

To examine the impact of time to thrombolytic treatment on multiple acute outcome variables in a single trial of thrombolysis in acute myocardial infarction.

DESIGN AND PATIENTS

Mortality and reinfarction rate were measured in 2770 patients with acute myocardial infarction who received thrombolysis within 12 hours in CORE, an international, dose ranging trial of poloxamer 188. Tc-99m sestamibi infarct size and radionuclide angiographic ejection fraction substudies included 1099 and 1074 patients, respectively.

RESULTS

Time to thrombolysis, subgrouped by intervals (< 2, 2-4, > or = 4-6, and > or = 6 hours), was significantly associated with infarct size (median 15.0%, 18.5%, 22.0%, 18.5% of left ventricle; p = 0.033), mean (SD) ejection fraction (51.5 (12.0)%, 48. 3 (13.9)%, 48.2 (13.3)%, 48.2 (15.0)%; p = 0.006), 35 day mortality (5.7%, 7.1%, 7.9%, 12.5%; p = 0.0004), six month mortality (7.3%, 8. 6%, 10.4%, 15.5%; p < 0.0001), and 35 day reinfarction rate (6.1%, 3. 2%, 4.0%, 0.9%; p = 0.0001).

CONCLUSIONS

In this single large trial, the beneficial effect of time to thrombolysis on infarct size and ejection fraction was restricted to treatment given within two hours of symptom onset, while the effect on mortality was evident over all time intervals. Reinfarction rate was higher in patients treated with earlier thrombolysis.

Diabetes mellitus is a strong negative prognostic factor in patients with myocardial infarction treated with thrombolytic therapy

OBJECTIVES

To assess the long-term prognostic values of baseline demographic data, occurrence of vectorcardiographic signs of reperfusion, left ventricular function and coronary angiographic features.

DESIGN

Longitudinal study of morbidity and mortality.

SETTING

Coronary care unit at Danderyd Hospital, Stockholm, Sweden.

SUBJECTS

A total of 222 patients (mean age 61 years) with a suspected acute myocardial infarction treated with thrombolysis were investigated and followed for 2-5 years (mean 1216 days).

MAIN OUTCOME MEASURES

Death or a new myocardial infarction.

RESULTS

Age above 55 years (P < 0.05), a previous diagnosis of diabetes mellitus (P < 0.005), hypertension (P < 0.05), heart failure (P < 0.001) and myocardial infarction (P < 0.05), a previous use of beta-blockers (P < 0.05) and an ejection fraction below 60% (P < 0.01) were predictors for death or a new myocardial infarction in univariate analysis. Sex, a previous history of smoking or angina pectoris, vectorcardiographic signs of reperfusion or degree of coronary artery disease had no prognostic values. In multivariate analysis including age above 55 years, a previous diagnosis of diabetes mellitus, hypertension and myocardial infarction, and an ejection fraction below 60%, only age (P < 0.05), diabetes mellitus (P < 0. 01) and ejection fraction (P < 0.05) were predictors for death or a new myocardial infarction.

CONCLUSIONS

The results of the present study emphasize the importance of diabetes mellitus as a long-term prognostic risk factor in patients with myocardial infarction treated with thrombolysis. Further studies are needed to determine the mechanisms behind this increased risk.

Microvascular repair following a modified crush-avulsion injury in a rat model: effect of recombinant human tissue-type plasminogen activator on the patency rate

The failure rate of replantations following a crush-avulsion type injury is high. This study has been designed to reproduce an effective standardized crush-avulsion injury model to the femoral artery of the rat and evaluate the antithrombotic efficacy of systemic intravenous administration of recombinant human tissue-type plasminogen activator (rt-PA). The crush-avulsion injury was reproduced by using a bulldog clamp and two hemostats and followed by microvascular repair. The animals were divided into three groups of 20 rats each and received either normal saline, heparin 100 U/kg body weight, or rt-PA 3.5 mg/kg body weight intravenously. Patency tests were performed 20 min and 48 h after blood flow reestablishment. Results showed that this experimental crush-avulsion injury model ensures low patency in the control group, whereas systemic rt-PA administration improves the patency rate statistically significantly compared to control and heparin groups at both 20 min and 48 h postrevascularization.

Prodromal unstable angina in acute myocardial infarction: prognostic value of short- and long-term outcome and predictor of infarct size

BACKGROUND

An estimated 50% of patients with myocardial infarction have prodromal unstable angina. There is controversy over whether prodromal unstable angina identifies a group of patients at lower risk of short- and long-term death and the clinical importance of recording this event.

METHODS

Of 207 patients enrolled at a single Global Utilization of Streptokinase and Tissue Plasminogen Activator for Occluded Coronary Arteries (GUSTO-I) site, 196 survived the 24 hours after presentation, achieved peak creatine kinase MB concentrations, and were classified as having either abrupt symptom onset or prodromal unstable angina in the 2 weeks before myocardial infarction. Creatine kinase MB peak was used to categorize infarct size as aborted myocardial infarction, minor myocardial damage, or extensive myocardial injury. Follow-up was performed at 24 hours, 30 days, 1 year, and 5 years. Multiple variables, including prodromal unstable angina, time to treatment, age, sex, previous infarction and infarct location, were analyzed for predicting infarct size. Also, these variables plus peak creatine kinase MB level and a combined variable of prodromal unstable angina and peak creatine kinase MB level were examined for predicting survival.

RESULTS

Mortality rate was 2.5% within 24 hours, 9.0% at 30 days, 13.5% at 1 year, and 27.1% at 5 years. Patients categorized as either aborted infarction or minor myocardial damage were significantly more likely to have prodromal unstable symptoms (81.3% vs 51.2%, P <.001) and better survival at each follow-up period. Prodromal presentation was the most significant predictor of infarct size category (P =.001). Five-year survival was predicted by age (P <.0001), peak creatine kinase MB level (P =.007), infarct location (P =.009), the combined variables (P =.029), and prodromal unstable angina (P =.017). Prodromal unstable angina had the highest odds ratio for 5-year survival at 3.83 (95% confidence interval 1.27-11.47).

CONCLUSIONS

Prodromal unstable angina is a strong predictor of infarct size and survival. Recognizing prodromal unstable angina is important for clinically assessing prognosis.

Post-hospitalization management of high-risk coronary patients

The major cause of morbidity and mortality associated with coronary atherosclerosis is plaque rupture, which often results in one of the acute coronary syndromes: unstable angina, non-Q-wave myocardial infarction (MI), or Q-wave MI. Plaque rupture may be attributable to the thickness of the overlying fibrous cap; thinner plaques are more likely to rupture. It appears that the presence of inflammation is a significant contributor to rupture. Acute-phase treatments are highly efficacious, but secondary prevention, often overlooked, also is life-saving. Diet, exercise, and medications are the interventions available for secondary prevention. Four classes of medications--aspirin, beta blockers, angiotensin-converting enzyme (ACE) inhibitors, and 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors (statins)--are also used in this setting with a high degree of success in reducing mortality and morbidity. Numerous studies have demonstrated a 30-50% reduction in mortality with aspirin. The reduction in mortality achieved with beta blockers in studies of patients after myocardial infarction are 15-50%. ACE inhibitors significantly reduce the risk of death from myocardial infarction in patients with coronary artery disease with or without myocardial infarction. Statins are beneficial even in patients whose cholesterol level is low to normal. Patients who were discharged on a statin showed a 50% reduction in mortality over those who did not receive statin therapy independent of lipid level. C-reactive protein, a marker of inflammation, is predictive of mortality, as are age and ejection fraction. Statins may be anti-inflammatory in addition to their lipid-lowering effect. Secondary-prevention strategies such as case management, electronic discharge prompting, better communication between referring physicians and cardiologists, and patient education may also have positive effects on after-discharge morbidity and mortality.

Medical decision making in the choice of a thrombolytic agent for acute myocardial infarction. Quebec Acute Coronary Care Working Group

Little is known about how physicians make decisions when the evidence is incomplete or controversial. While thrombolysis improves survival following acute myocardial infarction (AMI), conflicting evidence exists as to any specific agent's superiority, particularly if cost-effectiveness is considered. Using a Bayesian hierarchical model, the authors examined the patient, physician, and hospital characteristics that are related to the decision-making process concerning the choice of thrombolytic agent in a prospective registry of 1,165 AMI patients receiving thrombolysis. Tissue plasminogen activator (t-PA) was administered to 432 patients (31.8%) and streptokinase (SK) to the remainder. The presence of an anterior infarction, a previous myocardial infarction, low blood pressure, a cardiologist decision maker, younger age, and receiving treatment within six hours after the start of symptoms were independent predictors of receiving t-PA. The levels of importance that physicians accorded to these patient characteristics differed according to their practicing institutions. Generally, they followed evidence-based medicine and reasonably targeted high-risk patients to receive the more expensive t-PA. However, they also preferentially treated younger patients, where only a small absolute advantage appears to exist.

Clinical epidemiology of acute myocardial infarction

In the United States by mid-century, cardiovascular disease accounted for more than half of all deaths. In the second half of this century, 85% of reduction in age-adjusted mortality rates from all causes can be ascribed to the decline in death from cardiovascular disease and stroke. Approximately half of such dramatic decline in mortality rates from ischemic heart disease (IHD) can be explained by primary and secondary prevention and half by therapeutic improvements. Epidemiology of therapeutic regimens in acute myocardial infarction (AMI) indicates substantial increases in the use of thrombolytic therapy, aspirin, beta-blockers and, in some countries, coronary angioplasty. The long-term results of several thrombolytic trials have shown the persistence of early benefit until 10 years after AMI. However, approximately half of the patients with AMI are admitted to the hospital too late to fully benefit from thrombolytic therapy, and one fourth of eligible patients do not receive any form of reperfusion. Primary angioplasty is advocated by some as the treatment of choice in AMI. The present results are not convincing enough to induce the enormously complex and costly reorganization of the health system, allowing the immediate access to coronary angiography for all or most patients with AMI. However, stenting the infarct coronary artery at the site of previous occlusion appears to improve the immediate and medium-term results of coronary revascularization procedures. Approximately half of the AMI survivors are rehospitalized within 1 year after the index event, and postinfarction mortality rate remains exceedingly high. After AMI, prognostic and therapeutic procedures have been introduced in the absence of evidence from controlled trials of their effectiveness profile. Outcome research is needed to standardize effective post-AMI policies. Moreover, new strategies are needed to reduce the incidence and mortality rates of acute ischemic events. A number of new candidate risk factors for IHD are emerging; they are associated with endothelial dysfunction, thrombogenic state, and inflammatory state. It is hoped that advances in molecular approach to cardiovascular disease, molecular genetics and transgenic techniques will allow better understanding and more effective therapeutic strategies to prevent and control IHD.

Thrombolytic therapy versus primary angioplasty in the treatment of acute myocardial infarction

The quest to identify the acute interventional approach that will achieve the lowest mortality rate with the fewest adverse events has led to a continued controversy surrounding the relative merits of thrombolytic therapy compared with primary angioplasty in the setting of acute myocardial infarction. This article summarizes the benefits and limitations of each reperfusion strategy and highlights adjunctive therapies that will enhance either treatment strategy.

Which strategy is "best" after myocardial infarction? The Beta-blocker Strategy plus Implantable Cardioverter Defibrillator Trial: rationale and study design

The Beta-blocker Strategy plus Implantable Cardioverter Defibrillator (BEST-ICD) Trial is a multicenter prospective randomized trial that started in June 1998, in 95 centers in Italy and Germany. The trial will test the hypothesis whether, in high-risk post myocardial infarction (MI) patients already treated with beta blockers, electrophysiologic study (EPS)-guided therapy (including the prophylactic implantation of implantable cardioverter defibrillator [ICD] in inducible patients) will improve survival compared with conventional therapy. Patients eligible for the study are survivors of recent MI (> or = 5 and < or = 21 days), aged < or = 80 years, with left ventricular ejection fraction < or = 35% and > or = 1 of the following additional risk factors: (1) ventricular premature beats > or = 10/hour; (2) decreased heart rate variability (standard deviation of unusual RR intervals < 70 msec); and (3) presence of ventricular late potentials. Furthermore, all enrolled patients must be able to tolerate at least 25 mg of metoprolol per day. These patients constitute about 9% of all patients with recent MI and are expected to have a 2-year all-cause mortality > 25% of which 50% is anticipated to be from sudden death. The main criteria of exclusion from the study are (1) a history of sustained ventricular arrhythmia; (2) documentation of nonsustained ventricular tachycardia during the screening phase; and (3) the need for myocardial revascularization and contraindications or intolerance to beta-blocker therapy. Eligible patients will be randomized to 2 different therapeutic strategies: conventional strategy or EPS/ICD strategy. Patients allocated to the EPS/ICD strategy will undergo further risk stratification, and electrophysiologically inducible patients (approximately 35%) will receive prophylactic ICDs, in addition to the conventional therapy, whereas noninducible patients will be only conventionally treated. The primary endpoint of the study will be death from all causes. By hypothesizing a 30% reduction in the 2-year mortality (from 20% to 14%) in the EPS/ICD group compared with conventionally treated patients, 1,200 patients will have to be included. A triangular, 2-sided sequential design with preset boundaries, for a 5% significance level and 90% power to detect a reduction in 2-year mortality from 20% to 14%, will be used to permit early termination of the trial if the strategy is found to be efficacious, no difference, or inefficacious.

Gene therapy to promote thromboresistance: local overexpression of tissue plasminogen activator to prevent arterial thrombosis in an in vivo rabbit model

Tissue-type plasminogen activator (tPA) catalyzes the rate-limiting initial step in the fibrinolytic cascade. Systemic infusion of tPA has become the standard of care for acute myocardial infarction. However, even the relatively short-duration protocols currently employed have encountered significant hemorrhagic complications, as well as complications from rebound thrombosis. Gene therapy offers a method of local high-level tPA expression over a prolonged time period to avoid both systemic hemorrhage and local rebound thrombosis. To examine the impact of local tPA overexpression, an adenoviral vector expressing tPA was created. The construct was characterized functionally in vitro, and the function of the vector was confirmed in vivo by delivery to the rabbit common femoral artery. Systemic coagulation parameters were not perturbed at any of the doses examined. The impact of local overexpression of tPA on in vivo thrombus formation was examined subsequently in a stasis/injury model of arterial thrombosis. The construct effectively prevented arterial thrombosis in treated animals, whereas viral and nonviral controls typically developed occluding thrombi. This construct thus offers a viable technique for promoting a locally thromboresistant small-caliber artery.

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

OBJECTIVES

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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