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

Relation of clinically defined spontaneous reperfusion to outcome in ST-elevation myocardial infarction

In patients with ST-elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI), a patent infarct-related artery on initial angiography was associated with better angiographic results and improved prognosis compared with patients without spontaneous reflow. Little is known about the prevalence, clinical course, and optimal management of patients presenting with clinical signs of spontaneous reperfusion (SR). The objective was to evaluate characteristics and clinical outcomes in patients with STEMI with clinical signs of SR. The study included 710 consecutive patients with STEMI eligible for reperfusion therapy who were followed up for 30 days. SR was defined as a >or=70% reduction in sum ST elevation and pain severity before initiation of reperfusion therapy. SR was observed in 155 patients (22%). Although almost all patients with STEMI without SR underwent primary reperfusion using primary PCI (398 of 555 patients; 72%) or thrombolysis (125 of 555; 23%), most patients with SR were initially treated conservatively, and primary PCI was performed in only 13 patients (8%). Although patients with SR had a higher incidence of recurrent in-hospital ischemia, they developed smaller myocardial infarctions and sustained less in-hospital cardiogenic shock, heart failure, and electrical complications and had lower 7- and 30-day mortality rates. On multivariate analysis, SR remained significantly associated with a lower incidence of the combined end point of 30-day mortality, congestive heart failure, and recurrent acute coronary syndrome. In conclusion, despite initial conservative therapy, the outcome of patients with SR was markedly better than for patients without SR who underwent primary reperfusion.

Acute hyperglycemia and spontaneous reperfusion in acute myocardial infarction

BACKGROUND

Spontaneous reperfusion (SR) may occur in patients with ST elevation myocardial infarction (STEMI) prior to reperfusion therapy. Hyperglycemia is common on admission in patients with STEMI and is associated with a worse prognosis. Mechanisms remain unclear but may include impairment of coronary flow. The objective of this study was to examine whether acute hyperglycemia influenced the occurrence of SR in patients with STEMI.

METHODS

All patients presenting to our institution with acute STEMI with measurement of glucose levels on presentation were eligible. SR was defined as a combination of significant relief of chest pain associated with an at least 70% resolution of ST segment elevation on follow-up ECG.

RESULTS

465 patients were studied of whom 77 patients met criteria for SR. Average glucose levels were not significantly different between the SR and non-SR groups (10.0+/-5.6 mmol/l versus 10.1+/-5.3; P=NS). When patients were divided into normoglycemic and hyperglycemic groups, there was no significant difference in the percentages of such patients in the SR and non-SR groups. (52% versus 54%; P=NS).

CONCLUSIONS

Acute hyperglycemia on admission does not predict the occurrence of SR in a general population of patients with acute MI.

Infarct size in primary angioplasty without on-site cardiac surgical backup versus transferal to a tertiary center: a single photon emission computed tomography study

BACKGROUND

Primary percutaneous coronary intervention (PCI) performed in large community hospitals without cardiac surgery back-up facilities (off-site) reduces door-to-balloon time compared with emergency transferal to tertiary interventional centers (on-site). The present study was performed to explore whether off-site PCI for acute myocardial infarction results in reduced infarct size.

METHODS AND RESULTS

One hundred twenty-eight patients with acute ST-segment elevation myocardial infarction were randomly assigned to undergo primary PCI at the off-site center (n = 68) or to transferal to an on-site center (n = 60). Three days after PCI, (99m)Tc-sestamibi SPECT was performed to estimate infarct size. Off-site PCI significantly reduced door-to-balloon time compared with on-site PCI (94 +/- 54 versus 125 +/- 59 min, respectively, p < 0.01), although symptoms-to-treatment time was only insignificantly reduced (257 +/- 211 versus 286 +/- 146 min, respectively, p = 0.39). Infarct size was comparable between treatment centers (16 +/- 15 versus 14 +/- 12%, respectively p = 0.35). Multivariate analysis revealed that TIMI 0/1 flow grade at initial coronary angiography (OR 3.125, 95% CI 1.17-8.33, p = 0.023), anterior wall localization of the myocardial infarction (OR 3.44, 95% CI 1.38-8.55, p < 0.01), and development of pathological Q-waves (OR 5.07, 95% CI 2.10-12.25, p < 0.01) were independent predictors of an infarct size > 12%.

CONCLUSIONS

Off-site PCI reduces door-to-balloon time compared with transferal to a remote on-site interventional center but does not reduce infarct size. Instead, pre-PCI TIMI 0/1 flow, anterior wall infarct localization, and development of Q-waves are more important predictors of infarct size.

Spontaneous reperfusion in ST-elevation myocardial infarction: comparison of angiographic and electrocardiographic assessments

INTRODUCTION

Spontaneous reperfusion (SR) in ST-elevation myocardial infarction has traditionally been assessed by coronary angiography. The frequency of SR varies widely in prior studies, and the clinical implications in the modern reperfusion era are unclear. Accordingly, using data from the ASSENT 4 PCI (ASsessment of the Safety and Efficacy of a New Treatment Strategy with Percutaneous Coronary Intervention) study, we undertook a systematic assessment of SR using both electrocardiographic (ECG) and angiographic techniques.

METHODS AND RESULTS

Five hundred eighty-five patients randomized to the primary percutaneous coronary intervention (PCI) arm of ASSENT 4 PCI were studied: all had ECG and thrombolysis in myocardial infarction flow data available approximately 60 minutes after randomization and before PCI. Electrocardiographic SR (>/=70% ST-segment resolution) occurred in 14.9% (87/585) and angiographic SR (thrombolysis in myocardial infarction grade 3) in 14.7% (86/585) of patients. Thirty-day clinical outcomes of patients with ECG SR versus no ECG SR tended to have lower mortality (0% vs 3.4%, P = .091), a lower composite of death/shock/congestive heart failure (6.9% vs 12.2%, P = .148), and significant reductions in death/reinfarction (0% vs 5.6%, P = .014). By contrast, no such differences were evident in patients with angiographic SR versus no SR for death (2.3% vs 3.0%, P = 1.00), death/shock/congestive heart failure (9.3% vs 11.8%, P = .498), or death/reinfarction (2.3% vs 5.2%, P = .409).

CONCLUSIONS

Whereas the frequency of SR was comparable using either ECG or angiographic criteria, clinical outcomes were best aligned with ECG SR. These data support the role of the ECG in assessing reperfusion and likely reflect the overall impact of myocardial perfusion versus infarct-related artery epicardial patency alone.

[Adjuvant drug treatment in diabetic patients undergoing percutaneous coronary intervention]

The authors describe the adjuvant drug treatment during and after percutaneous coronary intervention in order to obtain the reduction of major cardiovascular events, focusing in diabetic patients. In the clinical follow-up of diabetic patients after PCI, special attention to the control measures of cardiovascular risk factors should be observed. Among those measures, a normal glycemic level is fundamental, which can be achieved with usual clinical care. Antiplatelet therapy is a controversy issue until know. Although combined antiplatelet therapy with aspirin and a thienopyridynic is well supported by a number of clinical trials, adding GPIIb/IIIa agents as adjuvants in diabetic patients should not be irrestrictive as suggested by some authors; they should be restricted to patients with a significative thrombotic burden.

Early glycoprotein IIb-IIIa inhibitors in primary angioplasty (EGYPT) cooperation: an individual patient data meta-analysis

Background:

Even though time-to-treatment has been shown to be a determinant of mortality in primary angioplasty, the potential benefits from early pharmacological reperfusion by glycoprotein (Gp) IIb–IIIa inhibitors are still unclear. The aim of this meta-analysis was to combine individual data from all randomised trials conducted on facilitated primary angioplasty by the use of early Gp IIb–IIIa inhibitors.

Methods and results:

The literature was scanned by formal searches of electronic databases (MEDLINE, EMBASE) from January 1990 to October 2007. All randomised trials on facilitation by the early administration of Gp IIb–IIIa inhibitors in ST-segment elevation myocardial infarction (STEMI) were examined. No language restrictions were enforced. Individual patient data were obtained from 11 out of 13 trials, including 1662 patients (840 patients (50.5%) randomly assigned to early and 822 patients (49.5%) to late Gp IIb–IIIa inhibitor administration). Preprocedural Thrombolysis in Myocardial Infarction Study (TIMI) grade 3 flow was more frequent with early Gp IIb–IIIa inhibitors. Postprocedural TIMI 3 flow and myocardial blush grade 3 were higher with early Gp IIb–IIIa inhibitors but did not reach statistical significance except for abciximab, whereas the rate of complete ST-segment resolution was significantly higher with early Gp IIb–IIIa inhibitors. Mortality was not significantly different between groups, although early abciximab demonstrated improved survival compared with late administration, even after adjustment for clinical and angiographic confounding factors.

Conclusions:

This meta-analysis shows that pharmacological facilitation with the early administration of Gp IIb–IIIa inhibitors in patients undergoing primary angioplasty for STEMI is associated with significant benefits in terms of preprocedural epicardial recanalisation and ST-segment resolution, which translated into non-significant mortality benefits except for abciximab.

Guidelines for therapy of ST-segment-elevation acute myocardial infarction in patients presenting to Partners Healthcare system hospital emergency departments

A major focus for individuals and organizations that study the quality of cardiovascular care is the timeliness of treatment for those patients who suffer an acute ST-elevation myocardial infarction (STEMI). We sought to develop guidelines that would inform the development and management of a more standardized approach to the treatment of STEMI within the 5 acute care hospitals that make up the Partners Healthcare acute care hospital network. In recent years much has been learned about how to deliver timely reperfusion therapy in STEMI and how to assess its outcome. As a component of the organization's mandate to promote the uniform high quality of care throughout the system, our group began studying the many aspects of the current treatment of STEMI within the system, we reviewed, summarized and debated the relevant literature, studied best practices and made recommendations for a system-wide approach to this problem. Our methods have included literature review, consultation with local and national experts, site visits throughout the system, web-based surveys of current attitudes within the system, interviews with stakeholders and consensus-development conferences. The result was not only the development of the following guidelines for therapy, but also an ongoing commitment to share patient-level data and outcomes for continuous quality assessment and improvement.

Glycoprotein IIb/IIIa inhibitor (tirofiban) in acute ST-segment elevation myocardial infarction

Studies have shown conflicting results for glycoprotein IIb/IIIa inhibitor (tirofiban) use in ST-segment elevation myocardial infarction (STEMI). The authors aimed to determine if an upstream conventional dose of tirofiban in addition to a standard treatment regimen improved coronary patency and clinical outcomes in patients with STEMI. A retrospective analysis of consecutive patients with STEMI, who underwent emergent percutaneous coronary intervention (PCI) in the authors' hospital from July 2000 to April 2006 was performed. All patients received loading doses of aspirin, clopidogrel or ticlopidine, and unfractionated heparin with or without tirofiban in the emergency department prior to PCI. It was found that adding a conventional dose of tirofiban to the standard treatment regimen prior to PCI did not improve coronary patency in STEMI patients. Tirofiban also failed to show favorable outcomes for 90 days of follow-up, but there was a favorable trend for short-term 30-day survival.

Relation of spontaneous reperfusion in ST-elevation myocardial infarction to more distal coronary culprit narrowings

Spontaneous reperfusion (SR) of the infarct-related artery may occur in patients with ST-segment-elevation myocardial infarctions (STEMIs). Limited data are available on the angiographic characteristics of these patients. The objective of this study was to determine if there are differences in the distance of the culprit lesion from the coronary ostium in patients with STEMIs with and without SR. Patients who presented with acute STEMIs<12 hours after pain onset and who underwent coronary angiography were entered into the study. Measurement of the distance from the coronary ostium to the culprit lesion was performed. A total of 469 patients with STEMIs were included in the study, of whom 77 met criteria for SR (significant relief of chest pain associated with >or=50% resolution of ST-segment elevation on follow-up electrocardiography) and 392 did not. A highly significant difference was seen in ostial to culprit lesion distance, with the culprit lesions in the SR group being more distal than those in the non-SR group (45+/-22 vs 39+/-20 mm, p<0.009). In conclusion, the findings of this study demonstrate that the location of the culprit lesion in patients with STEMIs who undergo SR is more distal in the involved artery than in patients with STEMIs who do not undergo SR.

Smoking cessation does not alter ST deviation pattern of recurrent myocardial infarctions

BACKGROUND

Myocardial infarction (MI) may be classified as ST elevation MI (STEMI) or non ST elevation MI (NSTEMI). We used the term recurrent MI (RMI's) to denote repeated MI episodes, in a particular patient, in which a different coronary site is responsible for each episode. Recently we reported that most patients with recurrent MI episodes will have either STEMI's or NSTEMI's but not both. A history of smoking was associated with recurrent STEMI's.

OBJECTIVE

To determine whether smoking cessation will alter the type of RMI in patients with an index MI of STE type.

METHODS

The analysis included 128 patients who underwent at least 2 MI episodes. We attempted to include only MI's of native vessels, without the presence of extra cardiac conditions that intensify myocardial ischemia. All 128 patients were active smokers who presented with an index MI of the STE type. Of these patients 94 had recurrent STEMI and 34 had recurrent NSTEMI (STE/NSTE group).

RESULTS

We identified all patients who were no longer active smokers at the time of the recurrent MI: there were 31 (33%) such patients in the STEMI group and 13 (38%) in the STE/NSTE group (p=NS).

CONCLUSION

Smoking cessation did not influence the type of recurrent MI in these patients.

Reperfusion strategies in acute ST-segment elevation myocardial infarction: a comprehensive review of contemporary management options

There are an estimated 500,000 ST-segment elevation myocardial infarction (STEMI) events in the U.S. annually. Despite improvements in care, up to one-third of patients presenting with STEMI within 12 h of symptom onset still receive no reperfusion therapy acutely. Clinical studies indicate that speed of reperfusion after infarct onset may be more important than whether pharmacologic or mechanical intervention is used. Primary percutaneous coronary intervention (PCI), when performed rapidly at high-volume centers, generally has superior efficacy to fibrinolysis, although fibrinolysis may be more suitable for many patients as an initial reperfusion strategy. Because up to 70% of STEMI patients present to hospitals without on-site PCI facilities, and prolonged door-to-balloon times due to inevitable transport delays commonly limit the benefit of PCI, the continued role and importance of the prompt, early use of fibrinolytic therapy may be underappreciated. Logistical complexities such as triage or transportation delays must be considered when a reperfusion strategy is selected, because prompt fibrinolysis may achieve greater benefit, especially if the fibrinolytic-to-PCI time delay associated with transfer exceeds approximately 1 h. Selection of a fibrinolytic requires consideration of several factors, including ease of dosing and combination with adjunctive therapies. Careful attention to these variables is critical to ensuring safe and rapid reperfusion, particularly in the prehospital setting. The emerging modality of pharmacoinvasive therapy, although controversial, seeks to combine the benefits of mechanical and pharmacologic reperfusion. Results from ongoing clinical trials will provide guidance regarding the utility of this strategy.

Defining standards of care for facilitated and direct percutaneous coronary intervention

Interventional cardiologists have a variety of options when it comes to facilitated and direct percutaneous coronary intervention (PCI). Over the years, several controversies have surrounded the choices made before and during this process. Questions have been raised over the value of stenting all patients and the use of filters and thrombectomy devices. A number of important clinical trials have also investigated the efficacy of platelet glycoprotein IIb/IIIa inhibitors. Considerable interest is now taking place on how best to reduce reperfusion delays and to improve anticoagulation in the catheterization laboratory. Since direct PCI is often a slow process, better use of existing and future therapies, as well as advances in patient transport, are expected to improve patient outcomes.

Primary percutaneous coronary intervention in acute myocardial infarction

Primary percutaneous coronary intervention (PCI) has emerged as the preferred therapy for acute ST-segment elevation myocardial infarction (STEMI), as multiple randomized clinical trials and pooled analyses have shown improved clinical outcomes compared with medical reperfusion. Unfortunately, medical centers with 24-hour PCI capability are concentrated in urban areas, relegating many patients in the United States to inferior medical reperfusion. Ongoing substantial research efforts are directed at optimizing mechanical reperfusion, including refinements in adjuvant medical therapy and the use of drug-eluting stents in the catheterization laboratory. Research efforts are also focusing on the implementation of streamlined transfer systems from community centers to tertiary care centers, akin to systems used in the trauma model. Furthermore, experience with the performance of primary PCI at community centers without onsite surgical backup is growing. This article summarizes data regarding the current state, challenges, and future directions of primary PCI for STEMI, emphasizing adherence to current American College of Cardiology/American Heart Association guidelines.

Effect of serum creatine kinase-MBmass on the early and hierarchical diagnosis of related artery reperfusion in acute myocardial infarction

AIM

To evaluate creatine kinase-MBmass (CK-MBmass) for the early diagnosis of infarct-related artery (IRA) patency after thrombolysis and the hierarchical diagnosis of related artery reperfusion (RAR).

PATIENTS AND METHODS

CK-MBmass and creatine kinase-MBactivity (CK-MBactivity) were measured kinetically in 48 patients treated with thrombolysis and 96 patients treated with routine drugs.

RESULTS

In the continuous-RAR (CRAR) group, the peak values of CK-MBmass and CK-MBactivity appeared at < or =12 h, the peak durations were maintained for < or =8 h before decreasing to normal at < or =42 h, which occurred more quickly than those values in the non-RAR (NRAR) group. In the temporary-RAR (TRAR) group, the peak values appeared at < or =12 h, but no significant differences were found between the TRAR and NRAR groups in the time that the peak durations lasted before decreasing to normal values. In the reobliteration group after RAR, the peak values appeared at < or =12 h, and the peak durations were maintained for < or =8 h. After returning to the normal, a second peak appeared, and the time required for the values to return to normal was prolonged significantly.

CONCLUSIONS

CK-MBmass could be used as an indicator of RAR after thrombolysis; and the kinetic changes of serum CK-MBmass could be used for the hierarchical diagnosis of RAR in acute myocardial infarction.

The effects of facilitated primary PCI by guide wire on procedural and clinical outcomes in acute ST-segment elevation myocardial infarction

BACKGROUND

Reperfusion of the infarct related artery (IRA) prior to PCI is prognostically important in patients with acute ST segment elevation myocardial infarction (STEMI). Reperfusion is either achieved spontaneously, facilitated by GP IIb/ IIIa inhibitors, or mechanically by crossing the guide wire beyond the lesion. In order to test the hypothesis that a visible coronary anatomy is independently associated with procedural and clinical outcomes, we evaluated the frequency and prognostic impact of guide wire facilitated reperfusion of the IRA before primary PCI.

METHODS AND RESULTS

We enrolled 311 consecutive patients with successful primary PCI for STEMI (TIMI grade > or =2 flow) within 12 h after onset of symptoms. Among these, 90 patients (28.9%) had a spontaneously reperfused IRA on initial angiogram, 56 patients (18.0%) achieved reperfusion after crossing of the guide wire, and 165 patients (53.1%) successful reperfusion only after PCI. Variables associated with successful guide wire facilitated reperfusion were younger age, no history of arterial hypertension, active smoking status, negative cardiac troponin T on admission, and an infarct in the territory of the right coronary artery. Patients with spontaneous reperfusion or reperfusion after crossing of the guide wire required less fluoroscopic time and less contrast material during angiography and had higher procedural success rates (TIMI grade 3 flow 91.1 vs 79.4%, p=0.048) than patients without initial reperfusion. In addition, patients with reperfusion after crossing the lesion with the guide wire had lower mortality rates at 30 days (3.6 vs 9.1%) and after a median of 16 months (3.6 vs 13.9%, p=0.03) than those with reperfusion after PCI.

CONCLUSIONS

Reperfusion of an occluded IRA by crossing the guide wire is associated with higher procedural success rates and better outcomes. Better roadmapping and device selection represent potential reasons but the exact mechanism for these benefits is still illusive.

Non-invasive low frequency vibration as a potential emergency adjunctive treatment for heart attack and stroke. An in vitro flow model

BACKGROUND

Myocardial infarction and stroke (arterial thrombosis) comprise the leading killers and sources of disability in the developed world, and incomplete thrombolysis along with high bleeding rates (plus late presentations to cathlabs) have prompted an intensive search for alternative or adjunctive emergency therapies. Transcutaneous ultrasound has been studied in remediation of thrombosis, but has been problematic due to poor penetration, risk of arterial damage, plus the apparent need for a highly skilled approach. Surprisingly there has been no reported studies on the much simpler application of transcutaneous low frequency vibration (well known for its superior penetration and flow enhancing characteristics) to assist arterial thrombolysis. The aim of our experiment therefore was to test the hypothesis whether vibration (i.e. approximately 100 Hz, 0.5 mm), when applied across an attenuating barrier, would assist recanulization of a thrombosed flow system held at arterial like pressure.

METHODS

A teddy bear with a 2 cm slab of New York Steak placed upon its chest surface was used as a test subject with an in-dwelling catheter (approximately 4.0 mm lumen) cannulated through the bear's thorax. In a series of test runs (n=30), a 2 h old (or older) blood clot was injected into the catheter such as to occlude it at a stenosis site (approximately 90% luminal narrowing) created by a clamp placed along the catheter within the teddy's chest region. A pressurized heparinized IV system was in all cases connected to the catheter such as to yield an "arterial like" lumen pressure proximal the obstruction. For each test run, after a twenty minute observation period to confirm stability of the occlusion, test groups where randomized to receive vibration to the slab of steak upon the teddy's "chest wall" (generally overlying the site of the thrombotic obstruction), or no vibration for an evaluation period of up to 45 min.

RESULTS

Catheter reflow occurred rapidly (median reflow-time 90 s) in the vibration groups within the evaluation period (i.e. 15/17), while the system remained otherwise blocked in the control groups receiving no vibration (i.e. 0/13). The difference in flow system patency rate for the vibration groups vs. the control groups was statistically significant (P=0.0000009).

CONCLUSIONS

The frequent and generally rapid re-establishment of flow in vibration groups compared to the complete absence of reflow in control groups confirms the hypothesis that vibration applied across a physical barrier assists clearance of a blood clot in a stenosed flow system under systemic levels of pressure. We studied the incidence of clearance of a blood clot within a stenosed, heparanized catheter system held at arterial like pressure that was treated with externally delivered low frequency vibration (applied proximate the thrombotic occlusion across an attenuating medium--a 2 cm thick slab of New York Steak--at approximately 100 Hz, 0.5 mm), versus no vibration. Reflow in test runs incorporating vibration occurred faster, and resulted in significantly greater recanulization rates in the catheter system versus test runs without vibration (P=0.0000009). Non-invasive vibration holds potential as an adjunct to pharmacologic therapy in treatment of acute arterial thrombosis. Further study of this technique appears warranted in live animal models.

Patency of infarct related artery after pharmacological reperfusion during transfer to primary percutaneous coronary intervention influences left ventricular function and one-year clinical outcome

BACKGROUND

Time-to-treatment is an important determinant of mortality in primary angioplasty for ST-segment elevation myocardial infarction (STEMI). Thus, the benefits in outcome observed with transferring for primary angioplasty in comparison with on-site thrombolysis may be reduced or even lost when long-distance transportation is required. Even though pharmacological reperfusion might overcome this limitation, no data have been reported so far on the prognostic role of early pharmacological recanalization in STEMI patients undergoing long-distance transportation for primary angioplasty.

METHODS

We enrolled 225 consecutive STEMI patients without shock, eligible for thrombolysis, with at least 90-minute transport time to our primary PCI center. During transport, patients received i.v. heparin 40 U/kg, alteplase 15 mg+35 mg infusion and abciximab 0.25 mg/kg+0.125 microg/kg/min infusion for 12 h.

RESULTS

Patients were divided into two groups according baseline angiography, which showed early pharmacological reperfusion (preprocedural TIMI flow 2+3) in 193 patients (85.8%) and no reperfusion (preprocedural TIMI flow 0+1) in 32 patients (14.2%). Despite no difference in postprocedural TIMI flow, early reperfusion was associated with better postprocedural myocardial perfusion (TMPG 3: 54.9% vs. 18.7%, p<0.0001), better improvement in left ventricular ejection fraction (LVEF) (from 55.6+/-8.6% to 58.8+/-10.4% p<0.001 with early reperfusion vs. 52.9+/-13.4% to 50.4+/-15.8% with no early reperfusion, p=NS) and 1-year outcome (p=0.002 log rank). In multivariate analysis, preprocedural TIMI flow 0+1 independently predicted death and reinfarction at 1 year, and lack of LVEF improvement at 6 months.

CONCLUSIONS

Early pharmacological reperfusion in STEMI patients undergoing long-distance transportation for primary angioplasty is associated with better postprocedural myocardial perfusion, better LVEF recovery at 6 months and improved 1-year clinical outcome.

The efficacy and safety of combination glycoprotein IIbIIIa inhibitors and reduced-dose thrombolytic therapy-facilitated percutaneous coronary intervention for ST-elevation myocardial infarction: a meta-analysis of randomized clinical trials

OBJECTIVE

We reviewed the literature and performed a meta-analysis comparing the safety and efficacy of adjunctive use of reduced-dose thrombolytics and glycoprotein (Gp) IIbIIIa inhibitors to the sole use of Gp IIbIIIa inhibitors before percutaneous coronary intervention (PCI) in patients presenting with acute ST-segment elevation myocardial infarction (STEMI).

BACKGROUND

Early reperfusion in STEMI is associated with improved outcomes. The use of reduced-dose thrombolytic and Gp IIbIIIa inhibitors combination before PCI in the setting of acute STEMI remains controversial.

METHODS

We performed a literature search and identified randomized trials comparing the use of combination therapy-facilitated PCI versus PCI done with Gp IIbIIIa inhibitor alone. Included studies were reviewed to determine Thrombolysis in Myocardial Infarction (TIMI)-3 flow at baseline, major bleeding, 30-day mortality, TIMI-3 flow after PCI, and 30-day reinfarction. We performed a random-effect model meta-analysis. We quantified heterogeneity between studies with I2. A value >50% represents substantial heterogeneity.

RESULTS

We identified 4 clinical trials randomizing 725 patients; 424 patients were pretreated with combination therapy before PCI, and 301 patients had Gp IIbIIIa inhibitor alone during PCI. Combination therapy-facilitated PCI was associated with a 2-fold increase in TIMI-3 flow upon arrival to the catheterization laboratory compared with the sole use of upstream Gp IIbIIIa inhibitors (192/390 patients [49%] versus 60/284 [21%]; relative risk [RR], 2.2; P < .00001). However, post-PCI TIMI-3 flow was similar between the 2 groups (279/319 patients [87%] versus 188/212 [88%]; RR, 0.99; P = .85). Major bleeding events significantly increased in the combination therapy group (40/420 patients [9.5%] versus 14/299 [4.7%]; RR, 2.2; P = .007). The 30-day mortality (15/424 patients [3.5%] versus 5/301 [1.7%]; RR, 1.47; P = .46) and 30-day reinfarction rate (5/424 patients [1.1%] versus 3/301 [1.0%]; RR, 0.96; P = .96) were similar in the 2 treatment groups.

CONCLUSIONS

Awaiting the results of the ongoing clinical trials, the current cumulative evidence does not support the routine use of combination of reduced-dose thrombolytic and Gp IIbIIIa inhibitor therapy-facilitated PCI for the treatment of STEMI.

Randomized Early Versus Late Abciximab in Acute Myocardial Infarction Treated With Primary Coronary Intervention (RELAx-AMI Trial)

OBJECTIVES

This prospective randomized trial evaluates the impact of early abciximab administration on angiographic and left ventricular function parameters.

BACKGROUND

Glycoprotein IIb/IIIa inhibitors improve myocardial reperfusion in patients with acute myocardial infarction (AMI) undergoing primary percutaneous coronary intervention (PCI), but optimal timing of administration remains unclear.

METHODS

Two-hundred ten consecutive patients with first AMI undergoing primary PCI were randomized to abciximab administration either in the emergency room (early group: 105 patients) or in the catheterization laboratory, after coronary angiography (late group: 105 patients). Primary end points were initial Thrombolysis In Myocardial Infarction (TIMI) flow grade, corrected TIMI frame count (cTFC), and myocardial blush grade (MBG), as well as left ventricular function recovery as assessed by serial echocardiographic evaluations.

RESULTS

Angiographic pre-PCI analysis showed a significantly better initial TIMI flow grade 3 (24% vs. 10%; p = 0.01), cTFC (78 +/- 30 frames vs. 92 +/- 21 frames; p = 0.001), and MBG 2 or 3 (15% vs. 6%; p = 0.02) favoring the early group. Consistently, post-PCI tissue perfusion parameters were significantly improved in the early group, as assessed by 60-min ST-segment reduction > or =70% (50% vs. 35%; p = 0.03) and MBG 2 or 3 (79% vs. 58%; p = 0.001). Left ventricular function recovery at 1 month was significantly greater in the early group (mean gain ejection fraction 8 +/- 7% vs. 6 +/- 7%, p = 0.02; mean gain wall motion score index 0.4 +/- 0.3 vs. 0.3 +/- 0.3, p = 0.03).

CONCLUSIONS

In patients with AMI treated with primary PCI, early abciximab administration improves pre-PCI angiographic findings, post-PCI tissue perfusion, and 1-month left ventricular function recovery, possibly by starting early recanalization of the infarct-related artery.

Early abciximab administration before primary percutaneous coronary intervention improves infarct-related artery patency and left ventricular function in high-risk patients with anterior wall myocardial infarction: a randomized study

BACKGROUND

Early abciximab administration before primary percutaneous coronary intervention (PPCI) for ST-segment elevation myocardial infarction (STEMI) is recommended in practice guidelines. However, the evidence supporting abciximab use before and during transfer for PPCI is limited. We investigated the effect of early abciximab administration on early reperfusion, ST-segment resolution, enzymatic infarct size, and left ventricular function in patients with first anterior wall STEMI.

METHODS

A total of 59 nonshock patients with STEMI admitted <12 hours to remote hospitals with anticipated delay to PPCI of <90 minutes were randomly assigned to 2 study groups: 27 patients received abciximab before transfer to catheterization laboratory (Early group), and 32 patients received abciximab immediately before PPCI (Late group).

RESULTS

Angiography revealed more frequent infarct-related artery patency in the Early group than in the Late group (TIMI 2 + 3: 48% vs 20%, P = .04). Better ST-segment resolution of >50% 60 minutes after PPCI was found in Early group than in the Late group (84% vs 56.7%, P = .04). The area under the curve for creatine kinase-MB indicated a significantly greater extent of myocardial injury in the Late group versus the Early group (8324 +/- 4185 vs 5938 +/- 3949 U/L . h, P = .04). There was a significant difference in the 30-day left ventricular end-systolic volume index (P = .02) and end-diastolic volume index (P = .05) in the echocardiography favoring the Early group.

CONCLUSIONS

Early abciximab administration before transfer for PPCI in patients with first anterior wall STEMI results in more frequent infarct-related artery patency before PPCI, better myocardial tissue perfusion after PPCI, with lower enzymatic infarct size and lower degree of left ventricular remodeling during 30-day follow-up.

Improving the management of patients after myocardial infarction, from admission to discharge

BACKGROUND

Recent developments in pharmacologic and device therapy, as well as initiatives to increase the use of standard orders and promote in-hospital communication, have improved the care of patients with myocardial infarction (MI). The increased presence of hospitalists, physicians who provide in-hospital care as a specialty, promises to provide further improvements.

OBJECTIVE

This article reviews current information on evidence-based care of the hospitalized MI patient, with a particular emphasis on identifying left ventricular dysfunction (LVD) and appropriate treatments.

METHODS

MEDLINE was searched for all large-scale clinical trials providing information on the care of post-MI patients with or without LVD and/or heart failure (HF), with no limit on time period. The search terms were post-myocardial infarction, large-scale, randomized, clinical trial, left ventricular dysfunction, and/or heart failure. All trials investigating therapies currently recommended in the American College of Cardiology/American Heart Association ST-elevation MI (ACC/AHA STEMI) guidelines and including post-MI patients with or without LVD and/or HF, as indicated by signs and symptoms of HF or Killip class, were included.

RESULTS

In the acute setting, the ACC/AHA STEMI guidelines recommend the use of aspirin, clopidogrel, beta-blockers, angiotensin-converting enzyme inhibitors, heparin (low molecular weight or unfractionated), and glycoprotein IIb/IIIa inhibitors (if the patient is undergoing a percutaneous coronary intervention). The guidelines recommend use of aldosterone antagonists and statins at discharge, in addition to continuation of all acute therapies. The ACC/AHA guidelines apply to all patients after MI and do not specify whether the recommended therapies are effective in post-MI patients with LVD or HE Reviewing the trials that included post-MI patients with LVD and/or HF, it appears that in some cases, only certain agents within a class have been evaluated (eg, post-MI beta-blocker trials often excluded patients with LVD, and the efficacy of atenolol has not been evaluated in post-MI patients with LVD or HF), and some agents have not shown as much efficacy as others in this high-risk patient population (eg, metoprolol appeared to be associated with poorer outcomes in this population than carvedilol). Rather than recommending an entire class, hospital care maps and critical-care pathway tools should incorporate the use of evidence-based agents.

CONCLUSIONS

The use of evidence-based care in the hospital has the potential to substantially reduce morbidity and mortality in post-MI patients with LVD and/or HE The hospitalist can facilitate the best practices and best care of the post-MI patient through the use of in-hospital critical-care pathway tools.

Atherosclerotic Plaque With Ultrasonic Attenuation Affects Coronary Reflow and Infarct Size in Patients With Acute Coronary Syndrome An Intravascular Ultrasound Study

BACKGROUND

No reflow following percutaneous coronary intervention (PCI) is a major concern in patients with acute coronary syndrome (ACS) and it may be influenced by the preexisting plaque type.

METHODS AND RESULTS

To evaluate the impact of plaque characteristics on coronary reflow following PCI in patients with ACS, a total of 110 patients (89 acute myocardial infarction, 21 unstable angina) were assessed by intravascular ultrasound. Plaque type was categorized as either atherosclerotic plaque without ultrasonic attenuation (group 1) or atherosclerotic plaque with attenuation (group 2). External elastic membrane, plaque plus media, and lumen area were measured. Coronary flow was assessed by Thrombolysis in Myocardial Infarction (TIMI) grade and TIMI frame count. Although the final TIMI frame count was similar between the 2 groups, TIMI frame count immediately after the first balloon inflation was significantly higher in group 2 (p=0.03). Despite the similar final TIMI grade and TIMI frame count, peak creatine kinase level was significantly higher (3,035+/-2,553 vs 1,950+/-1,958 IU/L, p=0.04) and fatal arrhythmia more frequently observed (16.4% vs 2.7%, p=0.04) in group 2 than in group 1.

CONCLUSIONS

Atherosclerotic plaque with ultrasonic attenuation may be related to a transient deterioration in coronary flow and as a result larger infarct size and higher incidence of fatal arrhythmia following PCI in patients with ACS. These results may help in selecting lesions suitable for distal protection devices.

Residual flow to the infarct zone against lethal ventricular tachyarrhythmias during the acute phase of myocardial infarction

BACKGROUND

The benefits of residual flow to the infarct zone have been demonstrated in acute myocardial infarction (AMI), but its relation to ventricular tachyarrhythmias remains uncertain.

HYPOTHESIS

This study was undertaken to test the hypothesis that residual flow is an important determinant of lethal ventricular tachyarrhythmias (sustained ventricular tachycardia or ventricular fibrillation) during the acute phase of AMI.

METHODS

We investigated the determinants of lethal ventricular tachyarrhythmias within 24 h after the onset of symptoms in 310 consecutive patients (256 men; age 57.4 +/- 11.5 years) with AMI undergoing primary angioplasty. Patients were divided into two groups: those with (Group 1, n = 40) and those without (Group 2, n = 270) lethal ventricular tachyarrhythmias. Residual flow was defined as the presence of anterograde flow (> or = Thrombolysis in Myocardial Infarction [TIMI] 2 flow) or good angiographic collaterals (> or = grade 2) on a preintervention angiogram.

RESULTS

Univariate determinants of lethal ventricular tachyarrhythmias were cardiogenic shock, systolic blood pressure, peak level of creatine kinase, culprit artery, spontaneous reperfusion, and residual flow. In multivariate analysis, however, cardiogenic shock (odds ratio [OR] = 4.79, 95% confidence interval [CI] 1.63-14.11, p = 0.004), residual flow (OR = 0.34, 95% CI 0.14-0.81, p = 0.015), and the right coronary artery as the culprit artery (OR = 2.09,95% CI 1.03-4.22, p = 0.040) were independent determinants of these arrhythmias. In-hospital death occurred in 10 patients and was more common in Group 1 than in Group 2 (12.5% vs. 1.9%, respectively, p < 0.001).

CONCLUSION

The absence of residual flow was associated with greater risk of lethal ventricular tachyarrhythmias during the acute phase of AMI, suggesting a protective role of residual flow against these arrhythmias in AMI.

Effect of clopidogrel plus aspirin on ST segments in patients with ST-elevation acute myocardial infarction

Spontaneous ST-segment resolution (STR) after acute ST-elevation myocardial infarction is associated with favorable outcomes. Effect on STR of newer, more powerful antiplatelet and antithrombotic agents is unclear. The aim of this study was to identify independent clinical and angiographic predictors of STR in patients with ST-elevation acute myocardial infarction before percutaneous coronary intervention. We studied 206 patients admitted with ST-elevation acute myocardial infarction, of whom 37 (18%) had STR. There were 12 deaths (5.8%) that occurred in the group without spontaneous STR. Patients with spontaneous STR were younger (55 vs 61 years old, p = 0.02), had shorter duration of symptoms (117 vs 212 minutes, p <0.0001), had preserved ejection fraction (55% vs 40%, p <0.0001), had shorter hospital stays, and had lower in-hospital arrhythmias or death. Independent predictors of STR, identified by stepwise logistic regression analysis, were early clopidogrel administration (odds ratio [OR] 2.10, 95% confidence interval [CI] 1.00 to 4.40, p = 0.045), single-vessel disease (OR 2.85, 95% CI 1.22 to 6.70, p = 0.02), chest pain duration (OR 0.98, 95% CI 0.98 to 0.99, p <0.0001), collaterals (OR 4.3, 95% CI 1.7 to 10.8, p = 0.002), circumflex as a culprit vessel (OR 4.74, 95% CI 1.5 to 14.95, p = 0.008), and coronary thrombus noted on angiography (OR 5.76, 95% CI 1.63 to 20.4, p = 0.006). In conclusion, early clopidogrel administration is associated with, and likely causal for, STR. Patients with thrombus, collateral flow, and circumflex culprit vessel are more likely to have STR. In addition, our study confirms previous findings that patients with STR have preserved left ventricular function and better hospital outcomes compared with those without STR.

Efficacy and Safety of Clopidogrel 600 mg Administered Pre-Hospitally to Improve Primary Percutaneous Coronary Intervention in Patients with Acute Myocardial Infarction (CIPAMI): Study Rationale and Design

Clopidogrel, in combination with acetylsalicylic acid, has become a mainstay of the pharmacological therapy for patients with acute coronary syndromes, especially in those undergoing percutaneous coronary interventions (PCI). While a series of studies has shown that pre-treatment with a loading dose of clopidogrel 300 or 600 mg prior to PCI is effective in reducing cardiovascular complications, the optimal dose and timing in various patient groups is still unclear. The primary objective of the present randomized, open-label Clopidogrel to Improve Primary percutaneous coronary Intervention in Acute Myocardial Infarction (CIPAMI) study is to evaluate the efficacy and the safety of a 600 mg loading dose of clopidogrel in addition to standard acetylsalicylic acid/heparin treatment in the pre-hospital setting in 654 patients with acute ST elevation myocardial infarction scheduled for primary PCI. The primary efficacy endpoint is the TIMI 2/3 patency of the infarct-related artery immediately prior to PCI. The rationale, design and methods of this study are described.

Early initiation of eptifibatide in the emergency department before primary percutaneous coronary intervention for ST-segment elevation myocardial infarction: results of the Time to Integrilin Therapy in Acute Myocardial Infarction (TITAN)-TIMI 34 trial

BACKGROUND

Early restoration of epicardial flow before primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) has been associated with improved clinical outcomes.

METHODS

We hypothesized that early administration of the glycoprotein IIb/IIIa inhibitor eptifibatide in the emergency department (ED) would yield superior epicardial flow and myocardial perfusion before primary PCI compared with initiating eptifibatide after diagnostic angiography in the cardiac catheterization laboratory (CCL). Three hundred forty-three patients with STEMI were randomized to either early ED eptifibatide (n = 180) or CCL eptifibatide (n = 163).

RESULTS

The primary end point (pre-PCI corrected TIMI frame count) was significantly lower (faster flow) with early eptifibatide (77.5 +/- 32.2 vs 84.3 +/- 30.7, P = .049). The incidence of normal pre-PCI TIMI myocardial perfusion was increased among patients treated in the ED versus CCL (24% vs 14%, P = .026). There was no excess of TIMI major or minor bleeding among patients treated in the ED versus CCL (6.9% [12/174] vs 7.8% [11/142], P = NS).

CONCLUSION

A strategy of early initiation of eptifibatide in the ED before primary PCI for STEMI yields superior pre-PCI TIMI frame counts, reflecting epicardial flow, and superior TIMI myocardial perfusion compared with a strategy of initiating eptifibatide in the CCL without an increase in bleeding risk.

Comparative early and late outcomes after primary percutaneous coronary intervention in ST-segment elevation and non-ST-segment elevation acute myocardial infarction (from the CADILLAC trial)

We determined the outcomes of patients with acute ST-segment elevation (STE) myocardial infarction (STEMI) and non-STEMI (NSTEMI) after primary percutaneous coronary intervention (PCI). The prognosis after primary PCI in STEMI has been extensively studied and defined. Outcomes of patients who undergo primary PCI for NSTEMI are less well established. In total, 2,082 patients with ongoing chest pain for > 30 minutes consistent with acute MI were randomized to balloon angioplasty versus stenting, each with/without abciximab. Of 1,964 patients, STEMI was present in 1,725 (87.8%) and NSTEMI in 239 (12.2%). Compared with STEMI, those with NSTEMI were more likely to have delayed time-to-hospital arrival (2.4 vs 1.8 hours, p = 0.0002) and increased door-to-balloon time (3.2 vs 1.9 hours, p < 0.0001). Patients with NSTEMI were more likely to have Thrombolysis In Myocardial Infarction grade 3 flow at baseline (37.3% vs 19.4%, p < 0.0001) and higher ejection fraction (58.7% vs 55.8%, p = 0.001), but similar rates of postprocedural Thrombolysis In Myocardial Infarction grade 3 flow. At 1 year, patients with NTEMI had similar mortality (3.4% vs 4.4%, p = 0.40) but higher rates of major adverse cardiac events (24.0% vs 16.6%, p = 0.007) that was driven by more frequent ischemic target vessel revascularization (21.8% vs 11.9%, p <0.0001). In conclusion, patients with acute MI without STE who are treated with primary PCI have marked delays to treatment, similar late mortality, and increased rates of ischemic target vessel revascularization compared with patients with STEMI, despite more favorable angiographic features at presentation and similar reperfusion success. The adverse prognosis of patients with NSTEMI should be recognized and efforts made to decrease reperfusion times.

Transport for abciximab facilitated primary angioplasty versus on-site thrombolysis with a liberal rescue policy: the randomised Holland Infarction Study (HIS)

AIMS

As of to date, the only large transportation trial comparing on-site fibrin-specific thrombolysis with transfer for primary angioplasty in patients presenting in a referral centre is the DANAMI-2 trial, with only 3% rescue angioplasty. The Holland Infarction Study (HIS) compared abciximab facilitated primary angioplasty (FP) with on-site fibrin-specific thrombolytic therapy (TT) with a liberal protocol-driven rescue angioplasty (transport to intervention centre in case < 50% ST resolution at 60 min).

METHODS AND RESULTS

Patients in a referral centre without shock and < 4.5 h of chest pain presenting with ST-elevation having > or = 12 mm ST-segment shift were randomised to either strategy. Of the originally planned 900 patients only 48 were included due to suspension of financial funding. Death, recurrent MI and stroke at one year was 8% for the FP-group and 22% for the TT-group (p = 0.2). Two hours after randomisation the rates of complete ST-segment resolution (> or =70%) were 52% and 35%, respectively (p = 0.2).

CONCLUSION

This prematurely discontinued randomised transportation trial shows favorable trends with respect to long-term clinical outcome and early ST-resolution for abciximab facilitated primary angioplasty. In view of the real world delays associated with interhospital transport for primary angioplasty, treatment strategies focusing on early fibrin-specific lysis with a liberal selective rescue policy are warranted.

Does Proximal Location of Culprit Lesion Confer Worse Prognosis in Patients Undergoing Primary Percutaneous Coronary Intervention for ST Elevation Myocardial Infarction?

ST segment elevation myocardial infarction (STEMI) from proximally located culprit lesion is associated with greater myocardium at jeopardy. In STEMI patients treated with thrombolytics, proximal culprit lesions are known to have worse prognosis. This relation has not been studied in patients undergoing primary percutaneous coronary intervention (PCI). In 3,535 STEMI patients with native coronary artery occlusion pooled from the primary angioplasty in myocardial infarction database, we compared in-hospital and 1-year outcomes between those with proximal (n = 1,606) versus non-proximal (n = 1,929) culprit lesions. Patients with proximal culprits were more likely to die and suffer major adverse cardiovascular events (MACE) during the index hospital stay (3.8% vs 2.2%, P = 0.006; 8.2% vs 5.8%, P = 0.0066, respectively) as well as during 1-year follow-up (6.9% vs 4.5%, P = 0.0013; 22% vs 17%, P = 0.003, respectively) compared to those with non-proximal culprits. After adjustment for baseline differences, proximal culprit was independently predictive of in-hospital death (adjusted odds ratio% 1.58, 95% confidence intervals, CI 1.05-2.40) and MACE (OR 1.41, CI 1.06-1.86), but not 1-year death or MACE. In addition, proximal culprit was independently associated with higher incidence of ventricular arrhythmias and sustained hypotension during the index hospitalization. The univariate impact of proximal culprit lesion on in-hospital death and MACE was comparable to other adverse angiographic characteristics, such as multivessel disease and poor initial thrombolysis in myocardial infarction flow, and greater than that of anterior wall STEMI. In conclusion, proximal location of the culprit lesion is a strong independent predictor of worse in-hospital outcomes in patients with STEMI undergoing primary PCI.

Reperfusion strategy for acute myocardial infarction in elderly patients aged 75 to 80 years

The increasing elderly population will influence the treatment policies adopted in cases of acute myocardial infarction. Considering reperfusion therapy in elderly patients with acute myocardial infarction, we compared three strategies, as follows: primary percutaneous coronary intervention (primary PCI: n = 26), facilitated PCI with half the standard dose of mutant tissue-type plasminogen activator (t-PA) (half + PCI: n = 24), and facilitated PCI with a standard dose of mutant t-PA (standard + PCI: n = 15) between patients 75 and 80 years of age. The rate of acquisition of thrombolysis in myocardial infarction (TIMI-3) flow on initial coronary arteriography was significantly lower in the primary PCI group than in the other two groups (7.7% in the primary PCI group vs 60% in the half + PCI and 66.7% in the standard + PCI group). The incidence of hemorrhagic complications including blood transfusion was not significantly different between primary PCI and facilitated PCI. Considering reperfusion therapy in elderly patients with acute myocardial infarction, we concluded that facilitated PCI may be effective in elderly patients aged 75-80 years.