Importance of time to reperfusion for 30-day and late survival and recovery of left ventricular function after primary angioplasty for acute myocardial infarction

Effect of continuous quality improvement analysis on the delivery of primary percutaneous revascularization for acute myocardial infarction: A community hospital experience

As time to reperfusion correlates with outcomes, a door-to-balloon time of 90 +/- 30 min for primary percutaneous coronary revascularization (PCI) for the treatment of acute myocardial infarction has been recently established as a guideline by the ACC/AHA. The purpose of this study is to assess the effects of a continuous quality assurance program designed to expedite primary angioplasty at a community hospital. A database of all primary PCI procedures was created in 1998. Two groups of consecutive patients treated with primary PCI were studied. Group 1 represented patients in the time period between 1 June 1998 to 1 November 1998 and group 2 represented patients in the period between 1 January 2000 and 16 June 2000. Continuous quality assurance analysis was performed. Modifications to the primary angioplasty program were initiated in the latter group. Time intervals to certain treatment landmarks were compared between the groups. Significant decreases in the time intervals from emergency room registration to initial electrocardiogram (8.4 +/- 8.2 vs. 3.7 +/- 19.5 min; P < 0.001), presentation to the catheterization laboratory to arterial access (13.5 +/- 12.9 vs. 11.6 +/- 5.8 min; P < 0.001), and emergency room registration to initial angioplasty balloon inflation (132.0 +/- 69.2 vs. 112 +/- 72.0 min; P < 0.001) were achieved. For the subgroup of patients presenting with diagnostic ST elevation myocardial infarction, a large decrease in the door-to-balloon time interval between group 1 and group 2 was demonstrated (114.15 +/- 9.67 vs. 87.92 +/- 10.93 min; P = NS), resulting in compliance with ACC/AHA guidelines. Continuous quality improvement analysis can expedite care for patients treated by primary PCI in the community hospital setting.

Facilitated primary coronary intervention with abciximab and very low dose of alteplase during off-hours compared with direct primary intervention during regular hours

In patients with acute myocardial infarction (AMI), the off-hour presentation is one of the major determinants of door-to-balloon delay. Moreover, the nighttime presentation is associated with increased mortality after primary coronary intervention (PCI). The prompt starting of a therapy able to start recanalization of the infarct-related artery before intervention might improve the results of off-hour primary PCI. We compared the outcome of 212 consecutive patients with AMI undergoing either direct or facilitated PCI according to the hour of presentation. Patients arriving off-hours were pretreated with alteplase (20 mg) and abciximab and underwent facilitated PCI. Patients presenting on-hours underwent direct PCI. A basal Thrombolysis in Myocardial Infarction (TIMI) flow grade 3 was observed in 1.0% of patients undergoing direct PCI and in 44% of patients undergoing facilitated PCI (P = 0.001). More patients starting PCI with a TIMI 3 flow achieved a postinterventional fast TIMI frame count (72.0% vs. 38.8% direct PCI group vs. 34.9% facilitated PCI group with basal TIMI 0-2; P = 0.001) and a TIMI perfusion grade 3 (66.0% vs. 38.8% direct PCI group vs. 39.7% facilitated PCI group with basal TIMI 0-2; P = 0.004). Preinterventional TIMI flow grade 3 was associated with a higher gain in left ventricular ejection fraction at 1 month (10.9% +/- 6.4% vs. 7.0% +/- 9.6% direct PCI group vs. 6.1% +/- 6.0% facilitated PCI group with basal TIMI 0-2; P = 0.005). No significant difference was observed in major bleedings, although there was a trend toward a higher risk in the facilitated PCI group. Patients in the facilitated PCI group achieving a basal TIMI 3 flow showed improved myocardial reperfusion and better left ventricular function recovery. Bleeding complications associated with combination therapy remained an important concern.

Relationship between Size of Myocardial Infarctions Assessed by Delayed Contrast-Enhanced MRI after Primary PCI, Biochemical Markers, and Time to Intervention

BACKGROUND

The quantitative assessment of myocardial infarctions using delayed contrast-enhanced magnetic resonance imaging (MRI) has recently been validated using postmortem histopathological animal studies. In a prospective study, we investigated the correlation between infarct size as assessed by delayed contrast-enhanced MRI, elevation of creatine kinase (CK), and c-reactive protein (CRP) as well as the time from onset of symptoms to intervention.

METHODS

Four to 10 days after immediate PCI in 45 acute ST-segment elevation myocardial infarction (STEMI) patients (<24 hour) with stenting of the infarct-related artery and treatment with abciximab, we performed gadolinium contrast-enhanced three-dimensional inversion recovery gradient-echo MR sequences with complete coverage of the LV-myocardium in short-axis slices. The mass of infarcted tissue based on the volume of hyperenhanced myocardium was calculated and linear regression analysis was performed to assess the correlation between absolute size of infarctions (g) as well as relative size (LV%) with peak values of CK, CRP, and the time to PCI.

RESULTS

There was a significant correlation between absolute size of infarctions (g) and peak CK values (r = 0.72; P < 0.001) as well as the relative size (LV%) and peak CK (r = 0.77; P < 0.001). No correlations were found between absolute size (r = 0.33) as well as relative size (r = 0.27) of infarctions and peak CRP. There was also no correlation between absolute (r = 0.29) as well as relative size of infarctions (r = 0.27) and the time from onset of symptoms to PCI.

CONCLUSIONS

In patients with acute STEMI (<24 hour) undergoing immediate PCI with stenting and treatment with abciximab, peak CK values correlated well with infarct size as assessed by delayed contrast-enhanced MRI. There were no correlations between infarct size and peak CRP as well as the time to intervention.

Magnitude and impact of treatment delays on weeknights and weekends in patients undergoing primary angioplasty for acute myocardial infarction (the cadillac trial)

In 2,082 patients in the CADILLAC trial, the outcomes of patients presenting during peak hours were compared with those presenting during peak hours (Monday to Friday 8a.m. to 8 p.m., n = 1,047, 51%) were compared with those of patients presenting during off-peak hours (weeknights from 8 p.m. to 8 a.m. and weekends, n = 989, 49%). Although treatment times to percutaneous coronary intervention (PCI) were delayed approximately 21 minutes, in patients with acute myocardial infarctions occurring on weeknights and weekends, this modest delay did not adversely affect procedural success, myocardial recovery, or survival after PCI.

Thrombolysis and Adjunctive Therapy in Acute Myocardial Infarction

This chapter about antithrombotic therapy for acute myocardial infarction (MI) is part of the Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy: Evidence Based Guidelines. Grade 1 recommendations are strong and indicate that the benefits do, or do not, outweigh risks, burden, and costs. Grade 2 suggests that individual patients' values may lead to different choices (for a full understanding of the grading see Guyatt et al, CHEST 2004; 126:179S-187S). Among the key recommendations in this chapter are the following: For patients with ischemic symptoms characteristic of acute MI of < 12 h in duration, and ST-segment elevation or left bundle-branch block (of unknown duration) on the ECG, we recommend administration of any approved fibrinolytic agent (Grade 1A). We recommend the use of streptokinase, anistreplase, alteplase, reteplase, or tenecteplase over placebo (all Grade 1A). For patients with symptom duration < 6 h, we recommend the administration of alteplase over streptokinase (Grade 1A). For patients with known allergy or sensitivity to streptokinase, we recommend alteplase, reteplase, or tenecteplase (Grade 1A). For patients with acute posterior MI of < 12 h duration, we suggest fibrinolytic therapy (Grade 2C). In patients with any history of intracranial hemorrhage, closed head trauma, or ischemic stroke within past 3 months, we recommend against administration of fibrinolytic therapy (Grade 1C+). For patients with acute ST-segment elevation MI whether or not they receive fibrinolytic therapy, we recommend aspirin, 160 to 325 mg p.o., at initial evaluation by health-care personnel followed by indefinite therapy, 75 to 162 mg/d p.o. (both Grade 1A). In patients allergic to aspirin, we suggest use of clopidogrel as an alternative therapy to aspirin (Grade 2C). For patients receiving streptokinase, we suggest administration of either i.v. unfractionated heparin (UFH) [Grade 2C] or subcutaneous UFH (Grade 2A). For all patients at high risk of systemic or venous thromboembolism (anterior MI, pump failure, previous embolus, atrial fibrillation, or left ventricular thrombus), we recommend administration of IV UFH while receiving streptokinase (Grade 1C+).

Impact of a critical pathway on acute myocardial infarction quality indicators

STUDY OBJECTIVE

To determine the impact of a critical pathway on acute myocardial infarction (AMI) quality indicators.

DESIGN

Retrospective chart review.

SETTING

Large university hospital.

PATIENTS

One hundred seventy-five patients who underwent primary percutaneous transluminal angioplasty for AMI (control group 89 patients, intervention group 86 patients).

MEASUREMENTS AND MAIN RESULTS

The medical records of the control group (1998-1999) were reviewed for door-to-balloon (DtB) time (the time between the patient's arrival at the emergency department and the first balloon inflation during a percutaneous transluminal coronary angioplasty procedure). Drug therapy prescribed at hospital discharge (aspirin, beta-blocker, angiotensin-converting enzyme [ACE] inhibitor, and lipid-lowering therapy) was also reviewed. The data collected for the control group were compared with the intervention group data (2000-2001). The impact of the pathway was evaluated using the Wilcoxon rank sum test, odds ratios (ORs), and chi2 tests. The DtB time was significantly lower in the intervention group versus the control group (91.5 vs 108 min, p < 0.01), and fewer intervention patients exceeded the guidelines with a DtB time longer than 120 minutes (OR 0.38, p < 0.01). In addition, the intervention group was more likely than the control group to be prescribed an ACE inhibitor (OR 3.7, p < 0.01) or lipid-lowering therapy (OR 3.7, p = 0.02) at discharge. Aspirin and beta-blockers were not prescribed differently in the intervention versus control groups (aspirin 95.2% vs 96.2%, beta-blockers 93.5% vs 92.6%).

CONCLUSION

These data suggest that in the current era of published treatment guidelines, implementation of a critical pathway can further improve AMI quality indicators and clinical care.

Acute coronary syndromes and diabetes mellitus

Patients with diabetes mellitus who present with acute ST-segment elevation myocardial infarction or non-ST-segment elevation acute coronary syndromes have a higher risk of adverse outcomes than patients without diabetes, and appear to derive greater benefit from evidence-based therapies. However, patients with diabetes mellitus are less commonly treated with proven therapies, so renewed efforts are needed to improve the quality of care and outcomes for patients with diabetes mellitus who present with acute coronary syndromes.

Serum myoglobin/carbonic anhydrase III ratio as a marker of reperfusion after myocardial infarction

BACKGROUND

Coronary patency is important for short- and long-term outcome after myocardial infarction. Serum myoglobin concentration is a sensitive marker of myocardial damage and its specificity can be improved by simultaneous measurement of carbonic anhydrase III, a skeletal muscle marker. In the present study we evaluated the role of myoglobin/carbonic anhydrase III ratio as a non-invasive marker of reperfusion.

METHODS

We measured myoglobin, carbonic anhydrase III and creatine kinase MB-fraction release serially in 29 patients with acute myocardial infarction treated with thrombolysis and in 28 patients treated with primary coronary angioplasty.

RESULTS

Thrombolytic therapy was followed by a 9.1+/-2.2-fold increase in myoglobin and 10.8+/-3.3-fold increase in creatine kinase MB-fraction during the first hour of treatment, while carbonic anhydrase III remained unchanged. The peak value of myoglobin/carbonic anhydrase III ratio was found at 2 h and that of creatine kinase MB-fraction at 8 h after thrombolysis. Knowledge of the reperfusion time point during primary angioplasty and follow-up of cardiac markers revealed that cut-off points of 3 and 10 h for the peak values of myoglobin/carbonic anhydrase III ratio and creatine kinase MB-fraction can be used as indicators for reperfusion, respectively. Myoglobin/carbonic anhydrase III ratio measured before treatment and at 2 and 4 h after the onset of treatment screened 23 of those 25 patients with probable reperfusion after thrombolysis.

CONCLUSIONS

We conclude that measuring myoglobin/carbonic anhydrase III ratio during the first hours after initiation of thrombolysis may be useful in evaluating the success of reperfusion after acute myocardial infarction.

Preprocedural TIMI flow and mortality in patients with acute myocardial infarction treated by primary angioplasty

OBJECTIVES

The aim of the study was to evaluate the impact of preprocedural Thrombolysis In Myocardial Infarction (TIMI) flow on one-year mortality in patients with ST-segment elevation myocardial infarction (STEMI) treated by primary angioplasty.

BACKGROUND

Although there is an excellent outcome conferred by primary angioplasty in patients with STEMI, the prognostic role of early recanalization in these patients has yet to be investigated.

METHODS

Our population is composed of 1,791 patients with acute myocardial infarction treated by primary angioplasty at our institution from 1994 to 2001. All angiographic, clinical, and follow-up data were prospectively collected. According to the TIMI risk score, patients were stratified in low- and high-risk groups.

RESULTS

Preprocedural TIMI flow was related to postprocedural TIMI flow grade 3 (p = 0.002), myocardial blush grade 2 to 3 (p < 0.001), enzymatic infarct size (p < 0.001), predischarge ejection fraction (p < 0.001), and one-year mortality (p < 0.05). Multivariate analysis showed that preprocedural TIMI flow grade 3 was an independent predictor of one-year survival in high-risk patients (p < 0.05).

CONCLUSIONS

This study shows that preprocedural TIMI flow grade 3 is an independent predictor of one-year survival in high-risk patients with acute myocardial infarction treated by primary angioplasty. These data suggest that all efforts should be made to obtain early and optimal restoration of antegrade flow, particularly in high-risk patients and when transportation to tertiary centers, with a conceivable further time delay, is required.

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.

Door-to-balloon delays with PCI in acute myocardial infarction

In the treatment of acute myocardial infarction (AMI), the length of time from symptom onset to revascularization is a crucial determinant of clinical outcomes such as mortality and reinfarction. Direct, or primary, percutaneous transluminal coronary angioplasty (PTCA) produces higher rates of infarct-related artery patency and improved clinical outcomes compared to thrombolytic therapy. However, primary PTCA is associated with an increased time interval from hospital arrival to revascularization, the so-called door-to-balloon time. Numerous data support the theory that increased door-to-balloon time reduces the benefits of primary PTCA in the treatment of AMI. Therefore, institutions that offer PTCA must strive to decrease door-to-balloon delays through the use of established treatment protocols and frequent assessment of performance.

Symptom-onset-to-balloon time and mortality in patients with acute myocardial infarction treated by primary angioplasty

OBJECTIVES

The aim of the study was to evaluate the relationship between symptom-onset-to-balloon time and one-year mortality in patients with ST-segment elevation myocardial infarction (STEMI) treated by primary angioplasty.

BACKGROUND

Despite the prognostic implications demonstrated in patients with STEMI treated with thrombolysis, the impact of time-delay on prognosis in patients undergoing primary angioplasty has yet to be established.

METHODS

Our study population consisted of 1,791 patients with STEMI treated by primary angioplasty from 1994 to 2001. All clinical, angiographic and follow-up data were collected. Subanalyses were conducted according to patient risk profile at presentation and preprocedural Thrombolysis In Myocardial Infarction (TIMI) flow.

RESULTS

A total of 103 patients (5.8%) had died at one year. Symptom-onset-to-balloon time was significantly associated with the rate of postprocedural TIMI 3 flow (p = 0.012), myocardial blush grade (p = 0.033), and one-year mortality (p = 0.02). A stronger linear association between symptom-onset-to-balloon time and one-year mortality was observed in non-low-risk patients (p = 0.006) and those with preprocedural TIMI flow 0 to 1 (p = 0.013). No relationship was found between door-to-balloon time and mortality. At multivariate analysis, a symptom-onset-to-balloon time >4 h was identified as an independent predictor of one-year mortality (p < 0.05).

CONCLUSIONS

This study shows that, in patients with STEMI treated by primary angioplasty, symptom-onset-to-balloon time, but not door-to-balloon time, is related to mortality, particularly in non-low-risk patients and in the absence of preprocedural anterograde flow. Furthermore, a symptom-onset-to-balloon time >4 h was identified as independent predictor of one-year mortality.

Transfer for Primary Angioplasty Versus Immediate Thrombolysis in Acute Myocardial Infarction

Background— The benefit of primary percutaneous coronary intervention (PCI) over thrombolysis has been clearly demonstrated in acute myocardial infarction (AMI). However, the best therapeutic strategy for a patient with AMI presenting to acute care services without catheterization facilities remains under debate. Our objective was to gather all available information from clinical trials comparing transfer of patients experiencing AMI for angioplasty versus immediate thrombolysis.

Methods and Results— We performed a meta-analysis of all data available from published randomized trials and from presentations in scientific sessions of major cardiology congresses comparing the 2 strategies. The primary end point was the combined criteria (CC) of death/reinfarction/stroke as defined in each trial. Relative risk (RR) evaluated the treatment effect. We identified 6 clinical trials including 3750 patients. Transfer time was always <3 hours. The CC was significantly reduced by 42% (95% confidence interval [CI] 29% to 53%, P <0.001) in the group transferred for primary PCI compared with the group receiving on-site thrombolysis. When CC parameters were considered separately, reinfarction was significantly reduced by 68% (95% CI, 34% to 84%; P <0.001) and stroke by 56% (95% CI, −15% to 77%; P =0.015). There was a trend toward reduction in all-cause mortality of 19% (95% CI, −3% to 36%; P =0.08) with transfer for PCI.

Conclusion— Even when transfer to an angioplasty center is necessary, primary PCI remains superior to immediate thrombolysis. Organization of ambulance systems, prehospital management, and adequate PCI capacity appear now to be the key issues in providing reperfusion therapy for AMI.

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.

Hospital performance with myocardial reperfusion therapy: are hospitals capable of meeting established guidelines?

OBJECTIVES

To determine whether hospitals are capable of delivering myocardial reperfusion therapy in a manner consistent with the American College of Cardiology/American Heart Association guidelines. DATA SOURCE AND STUDY SETTING: Data from the National Registry of Myocardial Infarction (NRMI)-2 and NRMI-3 were used. NRMI is an observational study, sponsored by Genentech, conducted from June 1994 through June 2000 and involving 1876 hospitals and 1,310,030 patients across the United States. The protocol calls for collecting data on all patients with a diagnosis of acute myocardial infarction. The setting was community and tertiary hospitals in the United States.

STUDY DESIGN

This observational study used process capability analysis.

PRINCIPAL FINDINGS

Overall, no hospital was deemed capable of delivering myocardial reperfusion therapy consistent with the American College of Cardiology/American Heart Association guidelines. The highest thrombolytic and angioplasty CPUs were 0.44 and 0.52, respectively-well below the traditional value of 1.0 signifying minimum capability. In addition, among the hospitals examined, there remained a wide degree of variability in process capability, ranging from -0.69 to 0.52.

CONCLUSIONS

Myocardial reperfusion therapy performance measurement systems relying solely on mean time-to-reperfusion conceal true process performance, thereby obscuring quality improvement opportunities and strategies for improvement. Health care providers, purchasers, regulators, and other organizations interested in measuring and improving health care quality are encouraged to incorporate process capability analysis into their myocardial reperfusion therapy performance measurement and quality management systems.

Relation of mortality of primary angioplasty during acute myocardial infarction to door-to-Thrombolysis In Myocardial Infarction (TIMI) time

For primary angioplasty of acute myocardial infarction (AMI), the relation of treatment benefit and time has been debated. The present study aimed to evaluate, in a single-center cohort of patients with ST-segment elevation AMI, which time intervals were carefully and consistently measured, and the relations among ischemic time, in-hospital delays, and in-hospital survival. We included 499 patients (mean age 59 years; 80% men) who underwent successful primary percutaneous transluminal coronary angioplasty (PTCA) for AMI admitted < or =6 hours after symptom onset. The population was divided into tertiles with respect to time between onset of symptoms and admission, onset of symptoms to Thrombolysis In Myocardial Infarction (TIMI) grade 3 flow, and time from admission to TIMI grade 3 flow. Univariate analysis followed by multiple logistic regression was performed using the variables linked to mortality in the univariate analysis to assess the relation between predictor variables and in-hospital mortality. The in-hospital mortality rate was 3.2%. There was no significant relation between the various tertiles of time intervals and in-hospital mortality. After linear logistic regression, only age (odds ratio [OR] 1.79 per 10 years), female gender (OR 3.56), and door-to-TIMI 3 time (OR 1.27 per 15 minutes) were independently correlated with in-hospital mortality.

Acute myocardial infarction complicated by early onset of heart failure: safety and feasibility of interhospital transfer for coronary angioplasty. Subanalysis of Killip II-IV patients from the PRAGUE-1 study

OBJECTIVE

The objective of this study is to assess the feasibility and safety of interhospital transfer (within up to 60 minutes) for primary/rescue coronary angioplasty of patients with myocardial infarction (AMI) complicated by an early onset of acute heart failure (AHF) admitted to a community hospital without PCI facilities.

DESIGN AND PATIENTS

From the multicenter randomized PRAGUE-1 study, a subgroup of 66 patients with AMI complicated by AHF on the first presentation to the community hospital were retrospectively analyzed. Group A patients (n = 21) were treated on site in community hospitals using thrombolysis (streptokinase), group B patients (n = 20) were transported with thrombolytic infusion to a PCI center for coronary angioplasty, and group C patients (n = 25) were immediately transported to a PCI center for primary angioplasty without thrombolysis.

RESULTS

No patient died during transportation. One group B patient developed ventricular fibrillation during transfer. The time delay from the onset of chest pain to reperfusion was > 142 minutes, and 253 and 251 minutes in groups A, B, and C, respectively. Hospital stay (16 vs 11 vs 10 days, P = NS) was shorter in the angioplasty groups. Transported patients (groups B, C) displayed a significant decrease in heart failure progression within the first 24 hours after treatment (48% vs 15% vs 8%, P < 0.05). The combined end point, i.e., mortality + nonfatal reinfarction (43% vs 25% vs 8%, P < 0.05), was significantly less frequent in the coronary angioplasty group.

CONCLUSIONS

Interhospital transfer for coronary angioplasty of patients with AMI complicated by an early onset of AHF is feasible and safe. Transport for angioplasty may even reduce the risk of heart failure progression and improve clinical outcome compared to immediate thrombolysis in the nearest community hospital.

Inter-hospital transport for primary angioplasty does not compromise left ventricular function: six-month echocardiographic follow-up of the PRAGUE 1 Study

The main aim of the present study was to investigate whether long distance interhospital transport for primary angioplasty (delayed mechanical reperfusion) influences the resulting left ventricular function after myocardial infarction as compared with thrombolysis at the nearest hospital (immediate pharmacological reperfusion). Primary coronary angioplasty is more effective than thrombolysis in restoring coronary flow in patients with acute myocardial infarction. It is not known whether a delay in reperfusion due to transport to an angioplasty centre compromises left ventricular function, and whether combination therapy (ie, thrombolysis during transport to an angioplasty centre) would help preserve ejection fraction. The "PRAGUE-1" Study randomised 300 patients with myocardial infarction admitted to community hospitals without a cath-lab into 3 groups: group A (thrombolysis, no transport, n = 99), group B (thrombolysis during transport to an angioplasty centre, n = 100), and group C (transport for primary angioplasty, n = 101). Transport distances were below 75 kilometres, and mean transport time was 38 minutes. This paper presents for the first time the echocardiographic data from the early (discharge, day 30) and mid-term (6 months) follow-up. Only patients who survived until discharge (A: 85, B: 88, C: 94) could be analysed. Ejection fraction improved between discharge and 6 months (P < 0.01) in all three groups: from 47% to 51% in group A, from 47% to 52% in group B, and from 48% to 52% in group C. The differences between the groups were not significant. The same differences were found for the wall motion score index. Left ventricular end-diastolic diameter did not differ between the groups/examinations. Greater improvement was documented in the period between hospital discharge and day 30, compared to the period between day 30 and 6 months. The time delay associated with an inter-hospital transport strategy for primary angioplasty did not compromise left ventricular function. The strategy of thrombolysis during transport did not further improve left ventricular function compared to transport for primary angioplasty alone.

The Level I Cardiovascular Center: Is It Time?

There is no uniform approach to treating the 1.5 million US citizens who have an acute myocardial infarction (AMI) each year. This contrasts with the trauma system developed to efficiently triage and treat the critically injured accident victim. Only two thirds of patients with ST-segment elevation AMI in the United States are treated with thrombolytic therapy or primary angioplasty (percutaneous coronary intervention [PCI]) which can reduce the 30-day mortality rate from approximately 15% to 6%-10%. The Early Retavase-Thrombolysis in Myocardial Infarction (ER-TIMI) 19 trial demonstrated that AMI patients who received prehospital thrombolytic therapy and were brought to the nearest receiving hospital experienced a 32-minute reduction in the time to treatment and time to ST-elevation resolution compared with those treated at their time of hospital arrival. This expedited therapy was associated with a low in hospital mortality rate (4.7%). The potential benefit of facilitated PCI with partial-dose thrombolysis and abciximab administration was demonstrated by the Strategies for Patency Enhancement in the Emergency Department (SPEED) investigators who found that double bolus recombinant plasminogen activator (reteplase) (5 + 5 megaunits) and abciximab with the addition of early PCI, resulted in a final infarct-related artery TIMI 3 flow rate of 86% compared with 77% with combination therapy alone. The Primary Angioplasty in Acute Myocardial Infarction (PAMI) investigators have shown that patients admitted with infarct-related artery TIMI 3 flow at the time of primary PCI had less than a 1% 6-month mortality. Treating AMI patients with prehospital, partial dose thrombolysis followed by immediate transport to a Level I cardiovascular center (bypassing the closest hospital if necessary) for facilitated infarct-related artery PCI has the potential to reduce the mortality in ST-elevation AMI patients from 6%-10% to less than 4% which could translate into saving approximately 500 lives per day in the United States. It is time to validate this strategy with a randomized clinical trial, the Prehospital Administration of Thrombolytic Therapy With Urgent Culprit Artery Revascularization trial (PATCAR).

Effect of prodromal angina pectoris on altering the relation between time to reperfusion and outcomes after a first anterior wall acute myocardial infarction

To test the hypothesis that prodromal angina may favorably alter the relation between time to reperfusion and outcomes after acute myocardial infarction (AMI), we studied 658 patients with a first anterior AMI: 200 patients with early reperfusion (time to reperfusion <or=2 hours), 205 patients with intermediate reperfusion (2 to 4 hours), 197 patients with late reperfusion (4 to 12 hours), and 56 patients without reperfusion (no reperfusion). Serial measurements of left ventricular ejection fraction (LVEF) were obtained before reperfusion therapy and before hospital discharge in 450 patients. Thirty-day mortality (3%, 4%, 8%, and 27% in early, intermediate, late, and no reperfusion, respectively, p <0.001) and the change in LVEF (8 +/- 14%, 6 +/- 13%, 6 +/- 12%, and -1 +/- 9%, respectively, p <0.001) were dependent on time to reperfusion and were worse if reperfusion was not obtained. In early reperfusion, 30-day mortality (3% vs 2%, p = 0.88) and improvement of LVEF (9 +/- 14% vs 8 +/- 14%, p = 0.59) were not significantly different between patients with prodromal angina and patients without prodromal angina. In intermediate or late reperfusion, prodromal angina was associated with lower 30-day mortality (3% vs 8%, p = 0.049) and a greater improvement in LVEF (8 +/- 13% vs 5 +/- 13%, p = 0.037). In no reperfusion, 30-day mortality (25% vs 27%, p = 0.87) and the change in LVEF (-1 +/- 11% vs -1 +/- 9, p = 0.87) were poor, regardless of prodromal angina. These findings suggest that prodromal angina might favorably alter the relation between time to reperfusion and outcomes after AMI. However, prodromal angina did not afford any benefits if reperfusion was not achieved.

Hyperoxemic perfusion for treatment of reperfusion microvascular ischemia in patients with myocardial infarction

In patients with acute myocardial infarction (AMI) primary angioplasty and stent placement is a more effective and better tolerated treatment than thrombolysis, and therefore, when logistics allow, this treatment is preferred and routinely used. However, successful reopening of an occluded coronary artery does not necessarily lead to recovery of left ventricular (LV) function. Post-AMI reduction in contractile function and ventricular remodeling may result in heart failure. There is evidence that reduced contractile function in the infarct zone is related to poor microvascular perfusion even after normalization of large-vessel flow by angiographic criteria following coronary recanalization. Failure to re-establish adequate tissue perfusion may be because of reperfusion injury, ischemia-induced microvascular damage, and plugging of the microcirculation by thrombus and plaque during mechanical recanalization. Experimental data support the hypothesis that reperfusion microvascular ischemia contributes to myocardial tissue injury over a prolonged time period. Hyperbaric oxygen therapy (HBO) attenuates microvascular dysfunction and reperfusion microvascular ischemia, as demonstrated in both experimental models and patients with AMI. However, treating patients in an HBO chamber or with a conventional oxygenator is impractical and difficult. Aqueous oxygen (AO) is a newly developed solution containing extremely high oxygen concentrations (1-3 ml O(2)/mL saline). The AO system mixes AO solution with a patient's blood from an arterial puncture and delivers the hyperoxemic blood to targeted ischemic myocardium via an infusion catheter for regional correction of hypoxemia and production of hyperoxemia. The system precisely controls the level of pO(2) without clinically significant microbubble formation. Hyperoxemic coronary infusion of AO in experimental models of AMI improved LV function and reduced infarct size compared with normoxemic controls,very likely as a result of microvascular blood flow improvement. The first clinical experiences with intracoronary infusion of AO solution demonstrated the therapy to be a safe and well tolerated in the setting of AMI after successful primary percutaneous transluminal coronary angioplasty. Its use was associated with significant progressive improvement in LV function as measured by ejection fraction and wall motion score index. Interestingly, such improvement was primarily due to functional recovery of infarct zone contractility. A larger randomized trial is currently underway to define the role of hyperoxemic coronary infusion in patients with AMI.

Defining optimal therapy for the thrombolysis-ineligible patient

Not all patients presenting with acute coronary syndrome (ACS) are able to receive reperfusion therapy. These include patients who present late (after 12 h) or who have bleeding diathesis. Studies have found a number of factors affect the decision to reperfuse. Other treatment options are needed for those patients with acute ST-elevation myocardial infarction (STEMI). Low-molecular weight heparin, such as enoxaparin, now offers these patients the opportunity for successful intervention. Several clinical trials have determined its superiority over unfractionated heparin as an adjunct during thrombolytic therapy. Currently, a trial is underway to determine the effect of enoxaparin in combination with tirofiban in patients with STEMI ineligible for reperfusion therapy. Blinded data for the entire patient cohort shows excellent efficacy and safety in these patients.

Prognostic significance of admission cardiac troponin T in patients treated successfully with direct percutaneous interventions for acute ST-segment elevation myocardial infarction

BACKGROUND

Cardiac troponin T (cTnT) elevations at admission indicate a high-risk subgroup of patients with acute ST-segment elevation myocardial infarction, possibly due to a higher failure rate of reperfusion therapies.

OBJECTIVE

We sought to determine the predictive role of admission cTnT in patients with ST-segment elevation myocardial infarction undergoing successful direct percutaneous coronary intervention.

METHODS

A total of 218 consecutive patients with ST-segment elevation myocardial infarction were enrolled. Patients were stratified according to admission cTnT and infarct location. They were followed prospectively for short-term and long-term outcomes. RESULTS A positive cTnT (47.7%) was associated with higher mortality rates at 30 days (14.4% vs. 3.5%, p = .003) and 12 months (17.3% vs. 4.4%, p =.007). cTnT allowed discrimination of patients at high and low risk for cardiac death at 30 days and 12 months among anterior (19.2% vs. 7.9%, p = .19, and 25% vs. 13.2%, p = .22, respectively) and, more impressively, among nonanterior acute myocardial infarction (9.6% vs. 1.3%, p = .04, and 11.5% vs. 1.3%, p = .017, respectively). In multivariate analysis, older age, anterior infarct location, and depressed left ventricular function were the most potent independent predictors of future risk. Among clinical variables available at admission, cTnT indicated independently a higher risk of cardiac death (odds ratio, 3.1 [1.07-9.01], p =.038). This increased risk associated with a positive cTnT was almost independent of time delays from onset of symptoms to admission (3.8 vs. 2.3 hrs in cTnT-positive vs. cTnT-negative patients, p <.001).

CONCLUSIONS

Admission cTnT is a strong predictor of future cardiac risk in patients with ST-segment elevation myocardial infarction, despite successful restoration of Thrombolysis in Myocardial Infarction grade 3 coronary flow by direct percutaneous coronary intervention.

Impact of spontaneous anterograde flow of the infarct artery on left ventricular function in patients with a first anterior wall acute myocardial infarction

To assess the impact of spontaneous anterograde flow of the infarct artery on outcomes in patients with acute myocardial infarction (AMI), we studied 478 patients with a first anterior wall AMI who underwent coronary angiography within 12 hours after the onset of chest pain; Thrombolysis In Myocardial Infarction (TIMI) 3 flow was obtained after reperfusion therapy. Patients were divided into 3 groups: 119 patients with spontaneous anterograde flow (initial TIMI 2 or 3 flow) of the infarct artery, 118 patients with an initially occluded artery (TIMI 0 or 1 flow) and time to angiography <or=2 hours (very early reperfusion), and 241 patients with an initially occluded artery and time to angiography of 2 to 12 hours (late reperfusion). Acute left ventricular (LV) ejection fraction (EF) was significantly higher in patients with spontaneous anterograde flow than in patients without (54 +/- 14% vs 47 +/- 10%, p <0.001). Predischarge LVEF was 65 +/- 14% in patients with spontaneous anterograde flow, 55 +/- 14% in patients with very early reperfusion, and 52 +/- 14% in patients with late reperfusion (p <0.001). Similar trends were observed in the changes in LVEF (12 +/- 14%, 8 +/- 14%, and 4 +/- 12%, p <0.001). Multivariate analysis showed that spontaneous anterograde flow was an independent predictor of preserved LV function, defined as a predischarge LVEF >or=55% (odds ratio 7.13, 95% confidence interval 3.10 to 16.4, p <0.001). In conclusion, although very early reperfusion improved LV function more than late reperfusion, spontaneous anterograde flow was associated with better acute and predischarge LV function after AMI compared with very early reperfusion of an initially occluded artery.

A randomized trial of transfer for primary angioplasty versus on-site thrombolysis in patients with high-risk myocardial infarction: the Air Primary Angioplasty in Myocardial Infarction study

OBJECTIVES

The Air Primary Angioplasty in Myocardial Infarction (PAMI) study was designed to determine the best reperfusion strategy for patients with high-risk acute myocardial infarction (AMI) at hospitals without percutaneous transluminal coronary angioplasty (PTCA) capability.

BACKGROUND

Previous studies have suggested that high-risk patients have better outcomes with primary PTCA than with thrombolytic therapy. It is unknown whether this advantage would be lost if the patient had to be transferred for PTCA, and reperfusion was delayed.

METHODS

Patients with high-risk AMI (age >70 years, anterior MI, Killip class II/III, heart rate >100 beats/min or systolic BP <100 mm Hg) who were eligible for thrombolytic therapy were randomized to either transfer for primary PTCA or on-site thrombolysis.

RESULTS

One hundred thirty-eight patients were randomized before the study ended (71 to transfer for PTCA and 67 to thrombolysis). The time from arrival to treatment was delayed in the transfer group (155 vs. 51 min, p < 0.0001), largely due to the initiation of transfer (43 min) and transport time (26 min). Patients randomized to transfer had a reduced hospital stay (6.1 +/- 4.3 vs. 7.5 +/- 4.3 days, p = 0.015) and less ischemia (12.7% vs. 31.8%, p = 0.007). At 30 days, a 38% reduction in major adverse cardiac events was observed for the transfer group; however, because of the inability to recruit the necessary sample size, this did not achieve statistical significance (8.4% vs. 13.6%, p = 0.331).

CONCLUSIONS

Patients with high-risk AMI at hospitals without a catheterization laboratory may have an improved outcome when transferred for primary PTCA versus on-site thrombolysis; however, this will require further study. The marked delay in the transfer process suggests a role for triaging patients directly to specialized heart-attack centers.

Relation of time to treatment and mortality in patients with acute myocardial infarction undergoing primary coronary angioplasty

The benefit of thrombolysis is dependent on time to treatment, but there is lack of evidence of this relation in patients undergoing primary percutaneous transluminal coronary angioplasty (PTCA). The hypothesis that the relation of time to treatment to mortality is dependent on patient risk was tested in a series of 1,336 patients who underwent successful primary PTCA and were stratified into "low-risk" and "not low-risk" patient groups according to the Thrombolysis In Myocardial Infarction criteria. After stratification, 942 patients (71%) were at not low risk, and 394 (29%) were at low risk. The 6-month mortality rate was 9.3% for not low-risk patients and 1.3% for low-risk patients (p <0.001). Among not low-risk patients, longer time to treatment was associated with increased age and a greater incidence of cardiogenic shock. Unadjusted mortality of the not low-risk patients increased from 4.8% to 12.9%, with increasing time to reperfusion up to 6 hours, whereas mortality of the low-risk group was constant, with an increased time to reperfusion. For the not low-risk group, the univariate analysis revealed a relation between time to treatment and mortality (odds ratio 1.35; 95% confidence interval 1.06 to 1.73, p = 0.017). Time to reperfusion was not an independent predictor of mortality at multivariate analysis. Mortality for not low-risk patients who undergo successful primary PTCA is related to the delay from symptom onset to treatment. The effects of other variables associated with a longer time to reperfusion may have a stronger impact on mortality, obscuring the incremental value of time to reperfusion at multivariate analysis.

Effect of treatment delay on outcomes in patients with acute myocardial infarction transferred from community hospitals for primary percutaneous coronary intervention

Outcomes were evaluated in 1,841 consecutive patients with acute myocardial infarction treated with primary percutaneous coronary intervention from 1984 to 2000 comparing patients transferred from community hospitals (n = 680) with patients presenting locally (n = 1,161). Baseline variables were similar except transferred patients had fewer prior infarctions (13% vs 21%, p <0.001) and underwent less prior bypass surgery (2.8% vs 6.0%, p = 0.002). Median times from symptom onset to emergency department arrival were similar, but door-to-balloon times and reperfusion times were approximately 1 hour longer in transferred patients (2.8 vs 1.9 hours [p <0.001] and 4.5 vs 3.5 hours [p <0.001], respectively). Despite longer treatment times, there were no significant differences between transferred and nontransferred patients in 30-day mortality (7.6% vs 8.1%, p = 0.73), reinfarction, urgent target vessel revascularization, stroke, and late mortality. After adjusting for differences in baseline variables, mortality remained similar between transferred and nontransferred patients (odds ratio 0.90, 95% confidence interval 0.59 to 1.36). Peak cardiac enzyme values were higher in transferred patients, but there were no differences in 6-month ejection fractions between groups. In conclusion, patients transferred from community hospitals for primary percutaneous coronary intervention have almost 1-hour additional treatment delay, but this does not appear to have a major adverse effect on clinical outcomes. These data should encourage further randomized trials to evaluate the role of transfer for mechanical reperfusion in patients presenting to community hospitals with acute myocardial infarction.

[Time intervals in primary angioplasty from onset of symptoms until restoration of blood flow]

INTRODUCTION AND OBJECTIVE

A limitation to the widespread use of primary angioplasty is delayed reperfusion. Most current data are from clinical trials and there is little information about the use of primary angioplasty in clinical practice. The objective of this study was to analyze the duration of each stage leading to primary angioplasty in a hospital where it is the treatment of choice for acute myocardial infarction.

PATIENTS AND METHOD

Prospective observational study of patients admitted to our hospital from April 2000 to August 2001 for acute myocardial infarction with an indication for reperfusion. The time intervals from onset of symptoms until the end of angioplasty were analyzed.

RESULTS

Primary angioplasty was performed in 201 of 218 patients with an indication for reperfusion (92%). Median values (percentiles 25-75) were: Time 1 (onset of symptoms-hospital arrival): 91 (50-150) minutes. Time 2 (hospital arrival-call to interventional team): 20 (10-49) minutes. Time 3: (call to interventional team-team arrival): 15 (0-20) minutes. Time 4: (team arrival patient arrival at the catheterization laboratory): 10 (5-15) minutes. Time 5 (patient arrival-opening of coronary artery): 20 (15-30) minutes. Time 6 (opening of coronary artery-TIMI III flow): 10 (0-25) minutes.

CONCLUSIONS

The most time-consuming stage in primary angioplasty was from the onset of symptoms until patient arrival at the hospital (Time 1). Inside the hospital, the most time-consuming stage was the diagnosis and decision to perform angioplasty (Time 2). The rates of primary angioplasty could be increased if delays in reperfusion were reduced with respect to those considered acceptable in current practice guidelines.

Predictors of door-to-balloon delay in primary angioplasty

In the treatment of acute myocardial infarction, delayed reperfusion therapy is associated with increased mortality. Predictors of delay have been described for fibrinolysis but not for primary percutaneous transluminal coronary angioplasty (pPTCA). Therefore, we studied 40,017 consecutive patients with acute myocardial infarction who underwent pPTCA in the National Registry of Myocardial Infarction between June 1994 and April 2000. Median door-to-balloon times were calculated, and factors independently associated with a delay of >120 minutes were determined by logistic regression. The median door-to-balloon time among all patients was 111 minutes (interquartile range 84 to 152). The proportion of patients with a delay of >2 hours was greater among those aged > or = 65 years (49% vs 41%), women (50% vs 42%), patients with contraindications to fibrinolysis (60% vs 41%), and those without chest pain on admission (61% vs 43%, all p <0.0001). Delay was also more common with transfer from another hospital (87% vs 38%), with presentation outside the hours of 8 A.M. to 4 P.M. (51% vs 38%), and in hospitals performing <49 pPTCAs/year (47% vs 41%, all p <0.0001). The strongest independent predictor of delay was hospital transfer, along with non-daytime presentation and low-volume centers. Older age, female sex, and non-white race were weaker predictors. Both patient and hospital factors are associated with delay in pPTCA after presentation. These findings may help design treatment algorithms to minimize delay, thus improving the survival benefit of pPTCA. These results may also help design trials of combination reperfusion strategies.

Primary angioplasty and selection bias inpatients presenting late (>12 h) after onset of chest pain and ST elevation myocardial infarction

OBJECTIVES

This study was designed to compare the in-hospital outcome of patients presenting with >12 h from onset of chest pain and acute ST elevation myocardial infarction (AMI) who received either immediate invasive or conservative therapy.

BACKGROUND

The benefits of fibrinolytic therapy diminish in patients presenting with AMI and onset of chest pain >12 h. Primary angioplasty has been suggested as a possible treatment for such patients, but they have been excluded from most trials of primary angioplasty. It remains unclear if an invasive treatment strategy is beneficial to these patients.

METHODS

Patients presenting with >12 h of chest pain and AMI were identified from the National Registry of Myocardial Infarction 2 database. Patients receiving invasive therapy <6 h after hospital admission were compared with those receiving conservative therapy. Short-term outcomes were compared on the basis of the initial therapy received. To help control for baseline differences in the groups, patients were matched with controls by propensity score methodology.

RESULTS

On preliminary analysis, in-hospital outcome was improved in terms of recurrent ischemia, angina, myocardial infarction and mortality in patients receiving initial invasive therapy (odds ratio [OR] = 0.67; 95% confidence interval [CI] 0.49 to 0.92 for mortality). After matching by propensity score, the mortality benefit persisted on bivariate analysis (3.5% vs. 5.0%, p = 0.036), though on multivariate analysis, only a non-significant but strong trend toward decreased mortality remained (OR = 0.73; 95% CI 0.53 to 1.01).

CONCLUSIONS

Patients receiving early invasive therapy had lower risk features on presentation. Selection bias may play an important role in choosing these patients' course of treatment and their subsequent outcomes. Certain patients presenting with AMI and duration of chest pain >12 h may benefit from early invasive therapy. These patients could be characterized in a randomized trial.

Impact of normalized myocardial perfusion after successful angioplasty in acute myocardial infarction

OBJECTIVES

We sought to evaluate and validate the ability of the angiographic myocardial blush grade to risk stratify patients after successful angioplasty in acute myocardial infarction (AMI).

BACKGROUND

Although epicardial Thrombolysis In Myocardial Infarction (TIMI)-3 flow is restored in >90% of patients undergoing primary percutaneous coronary intervention (PCI), normal myocardial perfusion may be present less frequently and may detrimentally impact survival.

METHODS

A cohort of 173 consecutive patients undergoing intervention within 24 h of AMI onset were studied. High-risk features of this population included failed thrombolysis in 39%, cardiogenic shock in 17% and saphenous vein graft culprit in 11% of patients.

RESULTS

Despite the restoration of TIMI-3 flow in 163 (94.2%) patients, myocardial perfusion, as evidenced by normal contrast opacification of the myocardial bed subtended by the infarct artery (myocardial blush), was normal in only 29.4% of patients with TIMI-3 flow following PCI, and in no patient with TIMI 0 to 2 flow. In patients in whom TIMI-3 flow was restored, survival was strongly dependent on the myocardial perfusion grade; one-year cumulative mortality was 6.8% with normal myocardial blush, 13.2% with reduced myocardial blush and 18.3% in patients with absent myocardial blush (p = 0.004).

CONCLUSIONS

Abnormal myocardial perfusion is present in most patients following primary or rescue PCI in AMI, despite restoration of brisk epicardial coronary flow. In high risk patients achieving TIMI-3 flow after intervention, the myocardial blush score may be used to stratify prognosis into excellent, intermediate and poor survival. Further study is warranted to examine whether adjunctive mechanical or pharmacologic strategies can further improve myocardial perfusion and survival of patients with acute myocardial infarction undergoing intervention.

Initial experience with hyperoxemic reperfusion after primary angioplasty for acute myocardial infarction: results of a pilot study utilizing intracoronary aqueous oxygen therapy

OBJECTIVES

The purpose of this study was to evaluate the feasibility and safety of intracoronary hyperoxemic reperfusion after primary angioplasty for acute myocardial infarction (MI).

BACKGROUND

Hyperoxemic therapy with aqueous oxygen (AO) attenuates reperfusion injury and preserves left ventricular (LV) function in experimental models of MI.

METHODS

In a multi-center study of patients with acute MI undergoing primary angioplasty (PTCA), hyperoxemic blood (pO(2): 600 to 800 mm Hg) was infused into the infarct-related artery for 60 to 90 min after intervention. The primary end points were clinical, electrical and hemodynamic stability during hyperoxemic reperfusion and in-hospital major adverse cardiac events. Global and regional LV function was evaluated by serial echocardiography after PTCA, after AO infusion, at 24 h and at one and three months.

RESULTS

Twenty-nine patients were enrolled (mean age: 58.9+/-12.6 years). Hyperoxemic reperfusion was performed successfully in all cases (mean infusion time: 80.8+/-18.2 min; mean coronary perfusate pO(2): 631+/-235 mm Hg). There were no adverse events during hyperoxemic reperfusion or the in-hospital period. Compared with baseline, a significant improvement in global wall motion score index was observed at 24 h (1.68+/-0.24 vs. 1.48+/-0.24, p < 0.001) with a trend toward an increase in ejection fraction (48.6+/-7.3% vs. 51.8+/-6.8%, p = 0.08). Progressive improvement in LV function was observed at one and three months, primarily due to recovery of infarct zone function.

CONCLUSIONS

Intracoronary hyperoxemic reperfusion is safe and well tolerated after primary PTCA. These preliminary data support the need for a randomized controlled trial to determine if hyperoxemic reperfusion enhances myocardial salvage or improves long-term outcome.

Left ventricular function and infarct size 20 months after primary angioplasty for acute myocardial infarction

OBJECTIVE

To study changes in left ventricular function and infarct size during long-term follow-up after acute myocardial infarction treated with primary angioplasty.

DESIGN

From 1996 to 1998, 100 consecutive patients were treated with primary angioplasty for acute ST-elevation myocardial infarction. Angioplasty was successful in 95% of the patients. Global left ventricular ejection fraction (LVEF) was determined by radionuclide ventriculography before discharge, after 6 weeks and after a mean follow-up time of 20 months. Infarct size was assessed by technetium 99m-tetrofosmin myocardial perfusion tomography (SPECT) at rest, performed at the same time intervals.

RESULTS

Mean LVEF was 56% at discharge, 55% after 6 weeks and 57% after 20 months of follow-up. No significant improvement in LVEF was observed. Only 8% of the patients at follow-up had LVEF lower than 40%. After 1 week, a mean perfusion defect of 19% was measured by SPECT. After 6 weeks and 20 months of follow-up, the mean perfusion defects were reduced to 14% (p < 0.001) and 15%, respectively.

CONCLUSION

Left ventricular function was well preserved with a mean LVEF of 57% 20 months after primary angioplasty for acute myocardial infarction. No significant change in LVEF was observed from 1 week after angioplasty to follow-up. Infarct sizes as assessed by SPECT imaging with tetrofosmin were reduced from 1 to 6 weeks, but did not change further during long-term follow-up. The reduction in the perfusion defects over time was probably due to gradual relief of stunning.

Importance of time to reperfusion on outcomes with primary coronary angioplasty for acute myocardial infarction (results from the Stent Primary Angioplasty in Myocardial Infarction Trial)

The mortality benefit of thrombolytic therapy for acute myocardial infarction (AMI) is strongly dependent on time to treatment. Recent observations suggest that time to treatment may be less important with primary percutaneous transluminal coronary angioplasty (PTCA). Patients with AMI of <12 hours duration, without cardiogenic shock, who were treated with primary PTCA from the Stent PAMI Trial (n = 1,232) were evaluated to assess the effect of time to reperfusion on outcomes. Thrombolysis In Myocardial Infarction grade 3 flow was achieved in a high proportion of patients regardless of time to treatment. Improvement in ejection fraction from baseline to 6 months was substantial with reperfusion at <2 hours but was modest and relatively independent of time to reperfusion after 2 hours (<2 hours, 12.3% vs > or =2 hours, 4.2%, p = 0.004). There were no differences in 1- or 6-month mortality by time to reperfusion (6-month mortality: <2 hours [5.5%], 2 to <4 hours [4.6%], 4 to <6 hours [4.5%], >6 hours [4.2%], p = 0.97). There were also no differences in other clinical outcomes by time to reperfusion, except that reinfarction and infarct artery reocclusion at 6 months were more frequent with later reperfusion. The lack of correlation between time to treatment and mortality in patients without cardiogenic shock suggests that the survival benefit of primary PTCA may be related principally to factors other than myocardial salvage. These data may also have implications regarding the triage of patients with AMI for primary PTCA.

Prognosis of acute myocardial infarction in the thrombolytic era: medical evaluation is still valuable

BACKGROUND

Modern and sophisticated technology for the management of myocardial infarction has progressively devalued medical evaluation.

HYPOTHESIS

This study was undertaken to assess the importance of the findings of medical evaluation at hospital presentation, in patients with acute myocardial infarction.

METHODS

Data from 590 thrombolytic-treated myocardial infarction patients were analyzed. The patients were grouped according to their clinical status on arrival at hospital. A modified Forrester classification--subset II was divided according to the absence (IIa) or presence (IIb) of symptoms--was applied. Short- (14 days) and long-term (up to 10 years) survival was analyzed and 19 independent variables were included in the multivariate models.

RESULTS

Short-term survival was 95.6% for subset I, 83.3% for subset IIa, 60% for subset IIb, 54.6% for subset III, and 34.8% for subset IV (P<0.001). By multiple regression analysis, lower clinical subsets (P<0.001), fewer coronary arteries with disease (P=0.006), younger age (P=0.014), absence of reinfarction (P=0.034), longer interval between streptokinase infusion and coronary arteriography (P=0.016), and higher left ventricular ejection fraction (P=0.037) demonstrated significant and independent correlation with short-term survival. Long-term survival for the total population was 71+/-3.6% for subset I, 54.4+/-8.5% for subset IIa, 20.8+/-9.4% for subset IIb, 54.5+/-15% for subset III, and 0% for subset IV (P<0.001). Using Cox regression analysis, lower clinical subsets (P<0.001), younger age (P<0.001), higher global left ventricular ejection fraction (P<0.001), and fewer coronary arteries with disease (P=0.021) correlated independently and significantly with long-term survival. When excluding data from patients who died before the short-term follow-up (n=532), lower clinical subsets remained an important predictor of long-term survival (P<0.001).

CONCLUSION

Clinical classification at hospital presentation is a powerful predictor of short- and long-term survival post-myocardial infarction.

Normal flow (TIMI-3) before mechanical reperfusion therapy is an independent determinant of survival in acute myocardial infarction: analysis from the primary angioplasty in myocardial infarction trials

BACKGROUND

Whereas survival after lytic therapy for myocardial infarction is strongly dependent on early administration, it is unknown whether the otherwise excellent outcomes in patients undergoing primary PTCA for acute myocardial infarction, in whom TIMI-3 flow rates of >90% may be achieved, can be further improved by early reperfusion.

METHODS AND RESULTS

Among 2507 patients enrolled in 4 PAMI trials undergoing primary PTCA, spontaneous reperfusion (TIMI-3 flow) was present in 16% at initial angiography. Compared with patients without TIMI-3 flow, those with TIMI-3 flow before PTCA had greater left ventricular ejection fraction (57+/-10% versus 53+/-11%, P=0.003) and were less likely to present in heart failure (7.0% versus 11.6%, P=0.009). Patients with initial TIMI-3 flow had significantly lower in-hospital rates of mortality, new-onset heart failure, and hypotension and had a shorter hospital stay. Cumulative 6-month mortality was 0.5% in patients with initial TIMI-3 flow, 2.8% with TIMI-2 flow, and 4.4% with initial TIMI-0/1 flow (P=0.009). By multivariate analysis, TIMI-3 flow before PTCA was an independent determinant of survival (odds ratio 2.1, P=0.04), even when corrected for by postprocedural TIMI-3 flow.

CONCLUSIONS

Patients undergoing primary PTCA in whom TIMI-3 flow is present before angioplasty present with greater clinical and angiographic evidence of myocardial salvage, are less likely to develop complications related to left ventricular failure, and have improved early and late survival. These data warrant prospective randomized trials of pharmacological strategies to promote early reperfusion before definitive mechanical intervention in acute myocardial infarction.

Time course and determinants of left ventricular function recovery after primary angioplasty in patients with acute myocardial infarction

OBJECTIVES

We sought to evaluate the importance of time in relation to treatment, time course and determinants of recovery of left ventricular (LV) function in patients with acute myocardial infarction (AMI) undergoing primary percutaneous transluminal coronary angioplasty (PTCA).

BACKGROUND

Myocardial salvage has been shown to be dependent on the time elapsed from the onset of AMI to reperfusion.

METHODS

Left ventricular function was evaluated at hospital admission, after angioplasty, at 24 h and 6 months by both echocardiography and angiography and at 1, 7, 30, 90 and 180 days by echocardiography in 101 consecutive patients.

RESULTS

Patients were allocated to three groups according to interval between symptom onset and angioplasty: <2 h (group A), 2 to 4 h (group B) and >4 h (group C). Patients in groups A and B showed a progressive improvement of LV function between day 7 and day 90, which became statistically significant at day 30 (p < 0.01). No LV function changes were noted in group C patients. Thrombolysis In Myocardial Infarction (TIMI) flow grade <3 at 24 h was not associated with any significant change in LV volume and function during the six-month follow-up period. Restenosis, when associated with TIMI flow grade 3 in the infarct-related vessel, did not influence LV function. Flow grade <3 of the infarct-related artery was not associated with any improvement of cardiac events independently from the time to treatment at the initial procedure.

CONCLUSIONS

Patients undergoing primary PTCA for AMI have a good recovery of LV function if TIMI flow grade 3 is restored within 4 h. Coronary angioplasty limits further remodeling of the LV in patients treated after 4 h.