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

Late outcomes of ST-elevation myocardial infarction treated by pharmaco-invasive or primary percutaneous coronary intervention

AIMS

Pharmaco-invasive percutaneous coronary intervention (PI-PCI) is recommended for patients with ST-elevation myocardial infarction (STEMI)who are unable to undergo timely primary PCI (pPCI). The present study examined late outcomes after PI-PCI (successful reperfusion followed by scheduled PCI or failed reperfusion and rescue PCI)compared with timely and late pPCI (>120 min from first medical contact).

METHODS AND RESULTS

All patients with STEMI presenting within 12 h of symptom onset, who underwent PCI during their initial hospitalization at Liverpool Hospital (Sydney), from October 2003 to March 2014, were included. Amongst 2091 STEMI patients (80% male), 1077 (52%)underwent pPCI (68% timely, 32% late), and 1014 (48%)received PI-PCI (33% rescue, 67% scheduled). Mortality at 3 years was 11.1% after pPCI (6.7% timely, 20.2% late) and 6.2% after PI-PCI (9.4% rescue, 4.8% scheduled); P < 0.01. After propensity matching, the adjusted mortality hazard ratio (HR) for timely pPCI compared with scheduled PCI was 0.9 (95% CIs 0.4-2.0) and compared with rescue PCI was 0.5 (95% CIs 0.2-0.9). The adjusted mortality HR for late pPCI, compared with scheduled PCI was 2.2 (95% CIs 1.2-3.1)and compared with rescue PCI, it was 1.5 (95% CIs 0.7-2.0).

CONCLUSION

Patients who underwent late pPCI had higher mortality rates than those undergoing a pharmaco-invasive strategy. Despite rescue PCI being required in a third of patients, a pharmaco-invasive approach should be considered when delays to PCI are anticipated, as it achieves better outcomes than late pPCI.

Improvement of clinical outcome in patients with ST-elevation myocardial infarction between 1999 and 2016 in China: The Prospective, Multicentre Registry MOODY study

BACKGROUND

Reports showed no change of 7-day mortality after primary percutaneous coronary intervention (PCI) for ST-elevation myocardial infarction (STEMI) between 2001 and 2011 in China. National rolling one-year interventional standardized training programme began in September 2009. However, the improvement in clinical outcome following STEMI PCI after 2011 remains unclear.

METHODS AND RESULTS

This multicentre MOODY registry study aimed to analyse the clinical improvement after STEMI PCI. Of a total of 9265 acute MI patients registered from 24 centres, 3142 STEMIs having a first medical contact time ≤12 hours and undergoing primary PCI were assigned to the Pre Group (n = 1014, between March 1999 and October 2010) or the Post Group (n = 2128, between 2010 November and 2016 October). The primary endpoint was in-hospital cardiac death. Study endpoints were also compared between trained and untrained operators and between experienced (≥50 primary PCIs/year) and inexperienced personnel. In-hospital death after PCI was 3.0% in the Pre Group, significantly higher than 1.6% in the Post Group (P = .035). The improvements in clinical outcome after PCI between the 2016 and Pre Groups were stably sustained through one-year follow-up. The significant reduction for in-hospital death was noted when primary PCI was performed by trained (1.4% vs 5.4%, P < .001) or experienced (2.7% vs 4.8%, P = .001) operators, compared to untrained or inexperienced operators, respectively. Inclusion of the untrained operator into the conventional risk model strongly enhanced the prediction for endpoints. Age, Killip Class 3, diabetes, trans-radial approach and system delay were five predictors of in-hospital death after primary PCI.

CONCLUSION

PCI for STEMI by a trained and experienced operator was associated with significant reduction of in-hospital death. Our results strongly warrant the need for promoting the current system response and patient education.

Comparison of outcomes in ST-segment depression and ST-segment elevation myocardial infarction patients treated with emergency PCI: data from a multicentre registry

Background

Traditionally, acute myocardial infarction (AMI) has been described as either STEMI (ST-elevation myocardial infarction) or non-STEMI myocardial infarction. This classification is historically related to the use of thrombolytic therapy, which is effective in STEMI. The current era of widespread use of coronary angiography (CAG), usually followed by primary percutaneous coronary intervention (PCI) puts this classification system into question.

Objectives

To compare the outcomes of patients with STEMI and ST-depression myocardial infarction (STDMI) who were treated with emergency PCI.

Methods

This multicentre registry enrolled a total of 6 602 consecutive patients with AMI. Patients were divided into the following subgroups: STEMI (n = 3446), STDMI (n = 907), left bundle branch block (LBBB) AMI (n = 241), right bundle branch block (RBBB) AMI (n = 338) and other electrocardiographic (ECG) AMI (n = 1670). Baseline and angiographic characteristics were studied, and revascularisation therapies and in-hospital mortality were analysed.

Results

Acute heart failure was present in 29.5% of the STDMI vs 27.4% of the STEMI patients (p < 0.001). STDMI patients had more extensive coronary atherosclerosis than patients with STEMI (three-vessel disease: 53.1 vs 30%, p < 0.001). The left main coronary artery was an infract-related artery (IRA) in 6.0% of STDMI vs 1.1% of STEMI patients (p < 0.001). TIMI flow 0–1 was found in 35.0% of STDMI vs 66.0% of STEMI patients (p < 0.001). Primary PCI was performed in 88.1% of STEMI (with a success rate of 90.8%) vs 61.8% of STDMI patients (with a success rate of 94.5%) (p = 0.012 for PCI success rates). In-hospital mortality was not significantly different (STDMI 6.3 vs STEMI 5.4%, p = 0.330).

Conclusion

These data suggest that similar strategies (emergency CAG with PCI whenever feasible) should be applied to both these types of AMI.

Factors associated with presenting >12 hours after symptom onset of acute myocardial infarction among Veteran men

BACKGROUND

Approximately 2/3 of Veterans admitting to Veterans Health Administration (VHA) facilities present >12 hours after symptom onset of acute myocardial infarction (AMI) ("late presenters"). Veterans admitted to VHA facilities with AMI may delay hospital presentation for different reasons compared to their general population counter parts. Despite the large descriptive literature on factors associated with delayed presentation in the general population, the literature describing these factors among the Veteran AMI population is limited. The purpose of this analysis is to identify predictors of late presentation in the Veteran population presenting with AMI to VHA facilities. Identifying predictors will help inform and target interventions for Veterans at a high risk of late presentation.

METHODS

In our cross-sectional study, we analyzed a cohort of 335 male Veterans from nine VHA facilities with physician diagnosed AMI between April 2005 and December 2006. We compared demographics, presentation characteristics, medical history, perceptions of health, and access to health care between early and late presenting Veterans. We used standard descriptive statistics for bivariate comparisons and multivariate logistic regression to identify independent predictors of late presentation.

RESULTS

Our cohort was an average of 64 ± 10 years old and was 88% white. Sixty-eight percent of our cohort were late presenters. Bivariate comparisons found that fewer late presenters had attended at least some college or vocational school (late 53% vs. early 66%, p = 0.02). Multivariate analysis showed that presentation with ST-elevation myocardial infarction (STEMI) was associated with early presentation (OR = 0.4 95%CI [0.2, 0.9]) and ≥2 angina episodes in the prior 24 hours (versus 0-1 episode) was associated with late presentation (OR = 7.5 95%CI [3.6,15.6]).

CONCLUSIONS

A significant majority of Veterans presenting to VHA facilities with AMI were late presenters. We found few differences between early and late presenters. Having a STEMI was independently associated with early presentation and reporting ≥2 angina episodes in the 24 hours prior to hospital admission was independently associated with late presentation. These independent predictors of early and late presentation are similar to what has been reported for the general population. Despite these similarities to the general population, there may be untapped opportunities for patient education within the VHA to decrease late presentation.

Perioperative glycaemic control for diabetic patients undergoing surgery

BACKGROUND

Patients with diabetes mellitus are at increased risk of postoperative complications. Data from randomised clinical trials and meta-analyses point to a potential benefit of intensive glycaemic control, targeting near-normal blood glucose, in patients with hyperglycaemia (with and without diabetes mellitus) being submitted to surgical procedures. However, there is limited evidence concerning this question in patients with diabetes mellitus undergoing surgery.

OBJECTIVES

To assess the effects of perioperative glycaemic control for diabetic patients undergoing surgery.

SEARCH METHODS

Trials were obtained from searches of The Cochrane Library, MEDLINE, EMBASE, LILACS, CINAHL and ISIS (all up to February 2012).

SELECTION CRITERIA

We included randomised controlled clinical trials that prespecified different targets of perioperative glycaemic control (intensive versus conventional or standard care)

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed risk of bias. We summarised studies using meta-analysis or descriptive methods.

MAIN RESULTS

Twelve trials randomised 694 diabetic participants to intensive control and 709 diabetic participants to conventional glycaemic control. The duration of the intervention ranged from just the duration of the surgical procedure up to 90 days. The number of participants ranged from 13 to 421, and the mean age was 64 years. Comparison of intensive with conventional glycaemic control demonstrated the following results for our predefined primary outcomes: analysis restricted to studies with low or unclear detection or attrition bias for infectious complications showed a risk ratio (RR) of 0.46 (95% confidence interval (CI) 0.18 to 1.18), P = 0.11, 627 participants, eight trials, moderate quality of the evidence (grading of recommendations assessment, development and evaluation - (GRADE)). Evaluation of death from any cause revealed a RR of 1.19 (95% CI 0.89 to 1.59), P = 0.24, 1365 participants, 11 trials, high quality of the evidence (GRADE).On the basis of a posthoc analysis, there is the hypothesis that intensive glycaemic control may increase the risk of hypoglycaemic episodes if longer-term outcome measures are analysed (RR 6.92, 95% CI 2.04 to 23.41), P = 0.002, 724 patients, three trials, low quality of the evidence (GRADE). Analysis of our predefined secondary outcomes revealed the following findings: cardiovascular events had a RR of 1.03 (95% CI 0.21 to 5.13), P = 0.97, 682 participants, six trials, moderate quality of the evidence (GRADE) when comparing the two treatment modalities; and renal failure also did not show significant differences between intensive and regular glucose control (RR 0.61, 95% CI 0.34 to 1.08), P = 0.09, 434 participants, two trials, moderate quality of the evidence (GRADE). We did not meta-analyse length of hospital stay and intensive care unit (ICU) stay due to substantial unexplained heterogeneity. Mean differences between intensive and regular glucose control groups ranged from -1.7 days to 2.1 days for ICU stay and between -8 days to 3.7 days for hospital stay (moderate quality of the evidence (GRADE)). One trial assessed health-related quality of life in 12/37 (32.4%) of participants in the intervention group and 13/44 (29.5%) of participants in the control group, and did not show an important difference (low quality of the evidence (GRADE)) in the measured physical health composite score of the short-form 12-item health survey (SF-12). None of the trials examined the effects of the interventions in terms of costs.

AUTHORS' CONCLUSIONS

The included trials did not demonstrate significant differences for most of the outcomes when targeting intensive perioperative glycaemic control compared with conventional glycaemic control in patients with diabetes mellitus. However, posthoc analysis indicated that intensive glycaemic control was associated with an increased number of patients experiencing hypoglycaemic episodes. Intensive glycaemic control protocols with near-normal blood glucose targets for patients with diabetes mellitus undergoing surgical procedures are currently not supported by an adequate scientific basis. We suggest that insulin treatment regimens, patient- and health-system relevant outcomes, and time points for outcome measures should be defined in a thorough and uniform way in future studies.

Targeted delivery of human VEGF gene via complexes of magnetic nanoparticle-adenoviral vectors enhanced cardiac regeneration

This study assessed the concept of whether delivery of magnetic nanobeads (MNBs)/adenoviral vectors (Ad)–encoded hVEGF gene (Ad_hVEGF) could regenerate ischaemically damaged hearts in a rat acute myocardial infarction model under the control of an external magnetic field. Adenoviral vectors were conjugated to MNBs with the Sulfo-NHS-LC-Biotin linker. In vitro transduction efficacy of MNBs/Ad–encoded luciferase gene (Ad_luc) was compared with Ad_luc alone in human umbilical vein endothelial cells (HUVECs) under magnetic field stimulation. In vivo, in a rat acute myocardial infarction (AMI) model, MNBs/Ad_hVEGF complexes were injected intravenously and an epicardial magnet was employed to attract the circulating MNBs/Ad_hVEGF complexes. In vitro, compared with Ad_luc alone, MNBs/Ad_luc complexes had a 50-fold higher transduction efficiency under the magnetic field. In vivo, epicardial magnet effectively attracted MNBs/Ad_hVEGF complexes and resulted in strong therapeutic gene expression in the ischemic zone of the infarcted heart. When compared to other MI-treated groups, the MI-M⁺/Ad_hVEGF group significantly improved left ventricular function (p<0.05) assessed by pressure-volume loops after 4 weeks. Also the MI-M⁺/Ad_hVEGF group exhibited higher capillary and arteriole density and lower collagen deposition than other MI-treated groups (p<0.05). Magnetic targeting enhances transduction efficiency and improves heart function. This novel method to improve gene therapy outcomes in AMI treatment offers the potential into clinical applications.

Tc-99m SPECT sestamibi for the measurement of infarct size

There are a variety of approaches to assess the efficacy of reperfusion therapy, and myocardial protection, in acute myocardial infarction. This review summarizes the available evidence validating the use of technetium-99m sestamibi single-photon emission computed tomography (SPECT) for this purpose. Multiple lines of evidence have validated its clinical utility. SPECT sestamibi infarct size has been used as an endpoint in multiple randomized clinical trials. A smaller number of clinical trials have used both early and later imaging with SPECT sestamibi to assess myocardium at risk and myocardial salvage. SPECT sestamibi has a number of limitations which must be recognized. Nevertheless, SPECT sestamibi infarct size is a well-validated measurement with a long track record of performance as an endpoint in multicenter, randomized clinical trials.

Measuring myocardial salvage

The efficacy of cardioprotective strategies can be quantified by myocardial salvage as an indicator of therapeutic benefit. Salvage is calculated as the difference between the area at risk (AAR) and the final infarct size (FIS). AAR has been quantified by angiographic assessment followed by quantification of FIS by biochemical ischaemic markers or imaging modalities such as cardiovascular magnetic resonance (CMR). Angiographical methods may overestimate AAR and since methodological differences may exist between different modalities, the use of different modalities for estimating AAR and FIS may not be recommended. (99m)Technetium (Tc)-Sestamibi single-photon emission tomography (SPECT) allows quantification of AAR and FIS by tracer injection prior to revascularization and after 1 month, respectively. SPECT provides the most validated measure of myocardial salvage and has been utilized in multiple randomized clinical trials. However, SPECT is logistically challenging, expensive, and includes radiation exposure. More recently, a large number of studies have suggested that CMR can determine salvage in a single examination by combining measures of myocardial oedema in the AAR exposed to ischaemia reperfusion with FIS quantification by late gadolinium enhancement. The T1- and T2-weighted CMR approaches for quantification of AAR utilize non-contrast, early and late gadolinium enhancement techniques. The technical progress, high spatial resolution and the potential for retrospective quantification of the AAR makes CMR the most appropriate technique for assessment of myocardial salvage. However, the optimum CMR technique for assessment of myocardial AAR remains to be defined. Consequently, we recommend a comprehensive CMR protocol to ensure reliable assessment of myocardial salvage.

Feasibility of an accurate assessment of myocardial salvage by comparing functional and perfusion abnormalities in post-reperfusion gated SPECT

BACKGROUND

Because of persistent stunning, post-treatment functional abnormalities could identify the initial risk area. The study aims to detect myocardial salvage using post-revascularization gated SPECT in acute myocardial infarction (AMI) treated by reperfusion therapy.

METHODS

In 36 AMI patients, we performed a first gated SPECT injecting (99m)Tc-sestamibi before primary percutaneous coronary intervention (PCI), and a second 5 days later. The salvage index defined by the two perfusion images was compared with the value obtained by subtracting in the second gated SPECT the extent of perfusion defect from the extent of wall thickening abnormalities.

RESULTS

The wall thickening salvage index correlated with the reference perfusion salvage index (Spearman's ρ = .92, P < .0001), with a 95% limit of agreement = ±.25. The agreement between the classifications in salvage index tertiles of the reference and of the wall thickening salvage index was good (kappa = .75). All patients with optimal PCI result and 18/24 of those with intermediate or poor outcome were correctly classified.

CONCLUSIONS

Comparing function and perfusion in a single post-PCI (99m)Tc-sestamibi gated SPECT it is possible to estimate myocardial salvage. This could have useful implications in studies comparing different treatment strategies for AMI.

Prognostic significance and determinants of myocardial salvage assessed by cardiovascular magnetic resonance in acute reperfused myocardial infarction

OBJECTIVES

The aim of the study was to determine the prognostic significance and determinants of myocardial salvage assessed by cardiovascular magnetic resonance (CMR) in reperfused ST-segment elevation myocardial infarction.

BACKGROUND

In acute myocardial infarction, CMR can retrospectively detect the myocardium at risk and the irreversible injury. This allows for quantifying the extent of salvaged myocardium after reperfusion as a potential strong end point for clinical trials and outcome.

METHODS

We analyzed 208 consecutive ST-segment elevation myocardial infarction patients undergoing primary angioplasty <12 h after symptom onset. T2-weighted and contrast-enhanced CMR was used to calculate the myocardial salvage index (MSI). Patients were categorized into 2 groups defined by the median MSI. The primary end point of the study was occurrence of major adverse cardiovascular events defined as death, reinfarction, and occurrence of new congestive heart failure within 6 months after the index event.

RESULTS

The median MSI was 48 (interquartile range 27 to 73). Major adverse cardiovascular events were significantly lower in the MSI >or= median group (2.9% vs. 22.1%, p < 0.001). The stepwise Cox proportional hazards model revealed that the MSI was the strongest predictor of major adverse cardiovascular events at 6-month follow-up (p < 0.001). All prognostic clinical (symptom onset to reperfusion), angiographic (Thrombolysis In Myocardial Infarction flow grade before angioplasty), and electrocardiographic (ST-segment resolution) parameters showed significant correlations with the MSI (p < 0.001 for all).

CONCLUSIONS

This study for the first time demonstrates that the MSI assessed by CMR predicts the outcome in acute reperfused ST-segment elevation myocardial infarction. Therefore, MSI assessment has important implications for patient prognosis as well as for the design of future trials intended to test new reperfusion therapy efficacy. (Myocardial Salvage Assessed by Cardiovascular Magnetic Resonance-Impact on Outcome; NCT00952224).

Coronary stenting versus balloon angioplasty for acute myocardial infarction: A meta-regression analysis of randomized trials

INTRODUCTION

Although stenting has been shown to reduce the need for target vessel revascularization (TVR) in acute myocardial infarction (AMI), the benefits in terms of mortality and reinfarction are still unclear. Previous meta-analyses have failed to include all currently available randomized trials. The aim of the current study was to perform an updated meta-analysis to evaluate the benefits of coronary stenting for AMI in terms of mortality, reinfarction, and TVR, and whether these benefits correlated with the patient's risk profile.

METHODS

The literature was scanned by formal searches of electronic databases (MEDLINE and CENTRAL) from January 1990 to September 2006. We examined all completed, published, randomized trials of coronary stenting for AMI. The following key words were used for study selection: randomized trial, myocardial infarction, reperfusion, primary angioplasty, rescue angioplasty, stenting, and balloon angioplasty. Information on study design, type of stent, inclusion and exclusion criteria, primary endpoint, number of patients, angiographic and clinical outcome, were extracted by two investigators. Disagreements were resolved by consensus.

RESULTS

A total of 13 randomized trials were identified and analyzed involving 6922 patients (3460 or 50% randomized to stent and 3462 or 50% to balloon). Stenting was not associated with a significant reduction in 30-day (2.9% versus 3.0%, p=0.81) and 1-year mortality (5.1% versus 5.2%, p=0.81), as compared to balloon angioplasty. However, a significant relationship was observed between patient's risk profile and mortality benefits from coronary stenting at 30-day (beta -0.63 [-25.4; -2.45], p=0.022) and 1-year follow-up (beta -0.61 [-15.9; -0.76], p=0.034). Stenting was associated with benefits in terms of TVR at both 30-day (3.1% versus 5.1%, p<0.0001) and 6 to 12 months (11.3% versus 18.4%, p<0.0001) follow-up, without any difference in terms of reinfarction.

CONCLUSIONS

Among AMI patients undergoing primary angioplasty, coronary stent implantation, when anatomically and technically feasible, may be considered, in addition to benefits in terms of TVR, to reduce mortality in high-risk patients, who may be identified by the use of validated risk scores.

A quantitative estimate of bare-metal stenting compared with balloon angioplasty in patients with acute myocardial infarction: angiographic measures in relation to clinical outcome

We performed a systematic review of all randomised controlled trials (RCTs) from the pre-drug-eluting-stent era comparing bare-metal stenting (BMS) with balloon angioplasty in patients with acute myocardial infarction (MI) to examine coronary angiographic parameters of infarct-related vessel patency and to relate the angiographic measures to clinical outcome. The search was restricted to published RCTs in humans. 10 RCTs, (6192 patients) were analysed. Compared with balloon angioplasty, BMS was associated with reduced rates of reocclusion (6.7% vs 10.1%, OR 0.62, 95% CI 0.40 to 0.96, p = 0.03) and restenosis (23.9% vs 39.3%, OR 0.45, 95% CI 0.34 to 0.59, p<0.001), but not with reduced rates of subacute thrombosis (1.7% in both groups). BMS showed a reduction in target vessel revascularisation (TVR; 12.2% vs 19.2%, OR 0.50, 95% CI 0.37 to 0.69, p<0.001), but not in mortality (5.3% vs 5.1%) or reinfarction (3.9% vs 4%). The findings of this study support BMS placement in acute MI. The discrepancy between angiographic and clinical parameters has important implications for future studies investigating further technical improvements in mechanical reperfusion therapy.

Comparison between stenting and balloon in elderly patients undergoing primary angioplasty for ST-segment elevation myocardial infarction

BACKGROUND

Coronary stenting has been shown to improve clinical outcome in comparison with balloon angioplasty in patients with ST-segment elevation myocardial infarction (STEMI). However, few data have been reported so far in the elderly. Thus, the aim of the current study was to evaluate the benefits from routine stenting in this high-risk subset of patients.

METHODS

In the Zwolle-6 randomized trial a total of 1683 consecutive patients with STEMI was randomized to stenting or balloon angioplasty without any exclusion criteria. One year follow-up data were available from all patients.

RESULTS

Among a total of 143 patients older than 75 years, 73 were randomized to stent and 67 to balloon angioplasty. No difference was observed in 1-year mortality (17.1% vs 11.9%, p=NS), reinfarction (9.2% vs 11.9%, p=NS), target vessel revascularization (15.8% vs 14.9%, p=NS) or major adverse cardiac events (28.9% vs 26.9%, p=NS) between the groups at 1-year follow-up.

CONCLUSION

In conclusion, our study showed that as compared to balloon angioplasty, the clinical benefits of routine coronary stenting in the setting of acute myocardial infarction may not be necessarily applicable to elderly patients.

Evolution of Left Ventricular Ejection Fraction and its Relationship to Infarct Size After Acute Myocardial Infarction

OBJECTIVES

The aim of this study was to investigate the evolution of left ventricular (LV) function and infarct size in patients with acute myocardial infarction (MI) treated with primary coronary stenting.

BACKGROUND

Little evidence exists on the relationship between LV function and evolution of infarct size after MI.

METHODS

This study included 626 patients with first acute MI who underwent 2 angiographic and 3 scintigraphic examinations within 6 months after the acute event. Angiographic left ventricular ejection fraction (LVEF) at baseline and at 6-month angiography, and perfusion defects before intervention and at 7- to 14-day and 6-month scintigraphy after intervention were measured. An analysis of 3-year follow-up was performed.

RESULTS

Scintigraphic perfusion defect (median [25th, 75th percentiles]) was 24.6% [14.0%, 41.0%] of LV before intervention; it was reduced to 11.0% [5.0%, 24.0%] of LV at 7 to 14 days and further to 8.0% [2.0%, 19.0%] of LV at 6 months (p < 0.001). The LVEF was 51.6 +/- 12.0% before intervention and increased to 57.4 +/- 12.8% at 6 months (p > 0.001). Independent predictors of LVEF change were baseline LVEF (p < 0.001), initial perfusion defect (p < 0.001), early reduction in perfusion defect (p < 0.001), late reduction in perfusion defect (p < 0.001), peak creatine kinase-MB (p < 0.001), and smoking (p = 0.05). Three-year mortality was 1.2% in patients with improved LF function versus 5.6% in patients with worsened LV function (relative risk 0.29, 95% confidence interval 0.09 to 0.90; p = 0.03).

CONCLUSION

Patients with acute MI show an improvement in LV function and a reduction in infarct size within 6 months after coronary reperfusion. This improvement is associated with better long-term survival.

Ability of mechanical reperfusion to salvage myocardium in patients with acute myocardial infarction presenting beyond 12 hours after onset of symptoms

BACKGROUND

The ability of primary percutaneous coronary intervention (PCI) to salvage myocardium in patients with acute ST-segment elevation myocardial infarction (STEMI) presenting >12 hours after symptom onset is questionable. The aim of this study was to assess the ability of primary PCI to salvage myocardium in patients with STEMI presenting between 12 and 48 hours after the symptom onset.

METHODS

In the BRAVE-2 trial, 365 patients with acute STEMI presenting between 12 and 48 hours from the symptom onset were randomized to an invasive (PCI) or a conservative treatment strategy. Two-hundred sixty-one patients enrolled in 2 centers had scintigraphy before randomization and 5 to 10 days later and constitute the cohort of the present study. Salvage index (proportion of initial perfusion defect salvaged) was the primary end point of this study.

RESULTS

There were 131 patients randomly assigned to the invasive treatment and 130 patients assigned to the conservative treatment. Initial perfusion defect (median [25th-75th percentiles]) did not differ between groups (17.0% [9.0-28.5] vs 16.0% [9.0-37.5] of the left ventricle; P = .99). The final infarct size, measured in the follow-up scintigraphy, was significantly smaller in patients assigned to the invasive treatment than in those assigned to the conservative treatment (8.0% [2.0-16.0] vs 12.0% [3.2-25.0] of the left ventricle; P = .004). Salvage index was 0.44 (0.13-0.80) in the invasive group versus 0.23 (0.0-0.50) in the conservative group (P < .001).

CONCLUSION

Primary PCI leads to significant myocardial salvage in patients with STEMI presenting between 12 and 48 hours after symptom onset.

Aortocoronary Shunting During Off-Pump Coronary Artery Bypass Surgery as Acute Reperfusion Strategy in ST-Elevation Myocardial Infarction

We report the case of a 43-year-old patient with acute ST-segment elevation anterior myocardial infarction who underwent off-pump coronary artery bypass grafting. To reduce the duration of ongoing myocardial ischemia, acute reperfusion of the infarcted coronary artery was achieved using an aortocoronary shunt, thereby perfusing the occluded left anterior descending artery. Under the protection of the aortocoronary shunt, the left internal thoracic artery was harvested and was thereafter anastomosed to the left anterior descending artery. The patient had an uneventful postoperative recovery.

Impact of routine stenting on myocardial perfusion and the extent of myocardial necrosis in patients undergoing primary angioplasty for ST-segment elevation myocardial infarction

BACKGROUND

Primary stenting for ST-segment elevation myocardial infarction (STEMI) has been shown to improve the outcome because of the benefits in terms of restenosis. However, still controversial are the benefits in terms of reperfusion. In the Zwolle-6 randomized trial, a consecutive cohort of patients with STEMI was randomized to balloon angioplasty or stenting, without exclusion criteria. In this study, we analyzed data on myocardial perfusion and the extent of myocardial necrosis.

METHODS

From April 1997 to October 2001, a total of 1683 consecutive patients with STEMI were randomized to stenting or balloon angioplasty. No exclusion criteria were applied. Myocardial perfusion was evaluated by myocardial blush grade and ST-segment resolution. The extent of myocardial necrosis was evaluated by enzymatic infarct size and predischarge ejection fraction. All data were prospectively collected.

RESULTS

A total of 785 patients (92.5%) in the stent group and 763 patients (91.5%) in balloon group underwent primary angioplasty. The 2 groups showed similar baseline characteristics. No difference was observed between stent and balloon in myocardial blush grade, complete ST-segment resolution, distal embolization, enzymatic infarct size, and predischarge ejection fraction at both intention-to-treat and actual treatment analysis, even when restricted to patients with anterior infarction. Time delay to treatment (earlier or later than 6 hours) did not affect the results. No difference was observed in 1-year mortality (6.0% vs 5.9%, P = NS).

CONCLUSIONS

As compared with balloon angioplasty, routine stenting does not improve myocardial perfusion, the rate of distal embolization, and the extent of myocardial necrosis in a large cohort of unselected patients with STEMI.

Plasmid-mediated VEGF gene transfer induces cardiomyogenesis and reduces myocardial infarct size in sheep

We have recently reported that in pigs with chronic myocardial ischemia heart transfection with a plasmid encoding the 165 isoform of human vascular endothelial growth factor (pVEGF165) induces an increase in the mitotic index of adult cardiomyocytes and cardiomyocyte hyperplasia. On these bases we hypothesized that VEGF gene transfer could also modify the evolution of experimental myocardial infarct. In adult sheep pVEGF165 (3.8 mg, n=7) or empty plasmid (n=7) was injected intramyocardially 1 h after coronary artery ligation. After 15 days infarct area was 11.3+/-1.3% of the left ventricle in the VEGF group and 18.2+/-2.1% in the empty plasmid group (P<0.02). The mechanisms involved in infarct size reduction (assessed in additional sheep at 7 and 10 days after infarction) included an increase in early angiogenesis and arteriogenesis, a decrease in peri-infarct fibrosis, a decrease in myofibroblast proliferation, enhanced cardiomyoblast proliferation and mitosis of adult cardiomyocytes with occasional cytokinesis. Resting myocardial perfusion (99mTc-sestamibi SPECT) was higher in VEGF-treated group than in empty plasmid group 15 days after myocardial infarction. We conclude that plasmid-mediated VEGF gene transfer reduces myocardial infarct size by a combination of effects including neovascular proliferation, modification of fibrosis and cardiomyocyte regeneration.

Aborted myocardial infarction: a new target for reperfusion therapy

Reperfusion therapy for ST-elevation acute coronary syndromes aims at early and complete recanalization of the infarct-related artery in order to salvage myocardium and improve both early and late clinical outcomes. Myocardial necrosis is usually confirmed and quantified by myocardial enzyme release in plasma. However, over 10% of patients treated with reperfusion therapy fail to develop an enzyme rise, but do exhibit transient ECG changes, which are consistent with an aborted myocardial infarction. The earlier the reperfusion therapy is instituted, the higher the incidence of aborted infarction. Treatment within an hour after symptom onset may result in 25% of aborted infarction and is in combination with complete (70%) ST-segment resolution associated with better survival. This endpoint is easy to define and occurs promptly in time. The faster that effective treatment is initiated, the more likely aborted infarction will occur. Given that mortality, re-infarction, and stroke are declining in incidence, we suggest the introduction of aborted infarction as an endpoint in clinical trials of ST-elevation acute coronary syndromes.

Coronary stenting and abciximab in primary angioplasty for ST-segment-elevation myocardial infarction

Advances in anti-platelet therapy and improvement of stent deployment techniques have improved the safety and efficacy of stenting in the setting of ST-segment-elevation myocardial infarction (STEMI). However, in randomized trials, routine coronary stenting does not reduce mortality and re-infarction, compared to balloon angioplasty. Further, the benefits in target vessel revascularization seem to be reduced when applied to unselected patients with STEMI. Direct stenting represents an attractive strategy with potential benefits in terms of myocardial perfusion. Future large randomized trials are needed to evaluate whether this strategy has a significant impact on outcome, and to provide a cost-benefit analysis of the unrestricted use of drug-eluting stents in this high-risk subset of patients. The additional use of abciximab reduces mortality in primary angioplasty. Since the feasibility of long-distance transportation has been shown in several randomized trials, early pharmacological pre-treatment may confer further advantages by early recanalization and shorter ischaemic time, particularly in high-risk patients. Further randomized trials are needed to clarify the potential benefits from early abciximab administration and the potential role of small molecules in primary angioplasty for STEMI.

Randomized evaluation of the effects of filter-based distal protection on myocardial perfusion and infarct size after primary percutaneous catheter intervention in myocardial infarction with and without ST-segment elevation

BACKGROUND

In acute myocardial infarction, distal embolization of debris during primary percutaneous catheter intervention may curtail microvascular reperfusion of the infarct region. Our randomized trial investigated whether distal protection with a filter device can improve microvascular perfusion and reduce infarct size after primary percutaneous catheter intervention.

METHODS AND RESULTS

We enrolled 200 patients who had angina within 48 hours after onset of pain plus at least 1 of 3 additional criteria: ST-segment elevation, elevated myocardial marker proteins, and angiographic evidence of thrombotic occlusion. Among the patients included (83% men; mean age, 62+/-12 years), 100 were randomly assigned to the filter-wire group and 100 to the control group. The primary end point was the maximal adenosine-induced Doppler flow velocity in the recanalized infarct artery; the secondary end point was infarct size estimated by the volume of delayed enhancement on nuclear MRI. ST-segment elevation myocardial infarction was present in 68.5% of the patients; the median time from onset of pain was 6.9 hours. In the filter-wire group, maximal adenosine-induced flow velocity was 34+/-17 compared with 36+/-20 cm/s in the control group (P=0.46). Infarct sizes, assessed in 82 patients in the filter-wire group and 78 patients in the control group, were 11.8+/-9.3% of the left ventricular mass in the filter-wire group and 10.4+/-9.4% in the control group (P=0.33). Thirty-day mortality was 2% in filter-wire group and 3% in the control group.

CONCLUSIONS

The filter wire as an adjunct to primary percutaneous catheter intervention in myocardial infarction with and without ST-segment elevation did not improve reperfusion or reduce infarct size.

Is routine stenting for acute myocardial infarction superior to balloon angioplasty? A randomised comparison in a large cohort of unselected patients

OBJECTIVE

To evaluate the impact of routine stenting, compared with balloon angioplasty, in unselected patients presenting with ST segment elevation myocardial infarction (STEMI).

DESIGN

Randomised trial.

SETTING

Tertiary referral centre.

PARTICIPANTS

All patients presenting with STEMI randomly assigned to stenting or balloon angioplasty. No exclusion criteria were applied.

MAIN OUTCOME MEASURE

The primary end point was combined death or reinfarction at one year's follow up.

RESULTS

1683 consecutive patients with STEMI were randomly assigned before angiography to stenting (n = 849) or balloon angioplasty (n = 834). A total of 785 patients (92.5%) in the stent group and 763 patients (91.5%) in the balloon group actually underwent primary angioplasty. The groups were comparable in terms of postprocedural TIMI (thrombolysis in myocardial infarction) flow, myocardial blush grade, and distal embolisation. No difference was observed in clinical outcome at both intention to treat (14% v 12.5%, not significant) and actual treatment analyses (12.4% v 11.3%, not significant).

CONCLUSIONS

Compared with balloon angioplasty, routine stenting does not seem to reduce death and reinfarction in a large cohort of unselected patients with STEMI.

Gender and myocardial salvage after reperfusion treatment in acute myocardial infarction

OBJECTIVES

The aim of this study was to investigate whether there are gender-associated differences in the amount of myocardial salvage after primary percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI).

BACKGROUND

Despite having a more adverse cardiovascular risk profile, women with AMI have similar or even better outcomes after primary PCI compared with men. The reasons for these findings are unclear.

METHODS

In this study we included 202 women and 561 men with AMI who underwent primary PCI in the setting of three randomized trials. The primary end point of the study was myocardial salvage index (proportion of initial perfusion defect salvaged by reperfusion therapy), obtained by paired scintigraphic studies performed 7 to 10 days apart.

RESULTS

The amount of myocardium at risk or initial perfusion defect (median [25th, 75th percentiles]) did not differ significantly between women and men (22.0% [12.0, 40.0] vs. 24.0% [14.0, 39.0] of the left ventricle [LV], p = 0.26). Final infarct size, measured in the follow-up scintigraphy, was significantly smaller in women than in men (6.0% [0.71, 18.7] vs. 10.0% [3.9, 21.8] of the LV, p = 0.001). Myocardial salvage index was 0.64 (0.35, 0.95) in women versus 0.50 (0.26, 0.77) in men (p < 0.001). After adjustment for baseline characteristics, female gender was an independent predictor of greater myocardial salvage after PCI (p = 0.002).

CONCLUSIONS

The efficacy of primary PCI in patients with AMI appears to be gender-dependent. Myocardial salvage achieved by primary PCI is greater in women than in men.

Primary angioplasty in acute myocardial infarction: Hypothetical estimate of superiority over aspirin or untreated controls

BACKGROUND

Primary percutaneous transluminal coronary angioplasty (PTCA) in the setting of ST-segment-elevation myocardial infarction has been compared with intravenous thrombolysis, but its effects versus no treatment are not known. Knowledge of the effects of PTCA in this setting is useful as a substantial minority of patients do not receive thrombolysis because of contraindications.

METHODS

A hypothetical primary PTCA versus placebo/control odds ratio was computed using a recently described statistical technique that employed the logarithm of the odds ratios of the pooled results of meta-analyses of PTCA versus thrombolysis and thrombolysis versus placebo or controlled trials.

RESULTS

Using data from 30 trials, the synthesized odds ratio for mortality for primary PTCA versus placebo/untreated controls is 0.56 (95% confidence interval [CI]: 0.46 to 0.68; P <0.00001), consistent with a 44% reduction. Primary PTCA and aspirin reduces mortality by 69% versus no aspirin (OR = 0.31; 95% CI: 0.21 to 0.45; P <0.00001). In a high-risk group of otherwise eligible patients with thrombolysis contraindications, the absolute benefit is estimated as 93 per 1000 treated (95% CI: 53 to 132 per 1000 treated). The risk of stroke is reduced with primary PTCA (OR = 0.46; 95% CI: 0.30 to 0.71; P = 0.0004).

CONCLUSION

In this setting, primary PTCA would hypothetically reduce the short-term risk of death by 44%. Despite the use of aggressive antithrombotic regimens, the risk of stroke would also be reduced substantially with primary PTCA.

Reperfusion treatment of ST-elevation acute myocardial infarction

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