Potential benefits of late reperfusion of infarcted myocardium. The open artery hypothesis

ALDH2 polymorphism and myocardial infarction: From alcohol metabolism to redox regulation

Acute myocardial infarction (AMI) remains a leading cause of death worldwide. Increased formation of reactive oxygen species (ROS) during the early reperfusion phase is thought to trigger lipid peroxidation and disrupt redox homeostasis, leading to myocardial injury. Whilst the mitochondrial enzyme aldehyde dehydrogenase 2 (ALDH2) is chiefly recognised for its central role in ethanol metabolism, substantial experimental evidence suggests an additional cardioprotective role for ALDH2 independent of alcohol intake, which mitigates myocardial injury by detoxifying breakdown products of lipid peroxidation including the reactive aldehydes, malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE). Epidemiological evidence suggests that an ALDH2 mutant variant with reduced activity that is highly prevalent in the East Asian population increases AMI risk. Additional studies have uncovered a strong association between coronary heart disease and this ALDH2 mutant variant. It appears this enzyme polymorphism (in particular, in ALDH2*2/2) carriers has the potential to have wide-ranging effects on thiol reactivity, redox tone and therefore numerous redox-related signaling processes, resilience of the heart to cope with lifestyle-related and environmental stressors, and the ability of the whole body to achieve redox balance. In this review, we summarize the journey of ALDH2 from a mitochondrial reductase linked to alcohol metabolism, via pre-clinical studies aimed at stimulating ALDH2 activity to reduce myocardial injury to clinical evidence for its protective role in the heart.

Late primary angioplasty (beyond 12 h): are we sure it should be avoided?

Optimal management for patients with ST-segment elevation myocardial infarction (STEMI) who arrive at a hospital late remains uncertain since evidence and real-world data are limited. Patients who present late with a STEMI are a heterogeneous population, and the clinical decision regarding percutaneous coronary intervention (PCI) should not be the same for all. One randomized clinical trial, multiple mechanistic studies, and contemporary registries suggest a presumed benefit for a prompt restoration of coronary flow even in late presenting STEMI. Crucial elements in decision-making are the presence of haemodynamic or electrical instability, and ongoing ischaemic signs or symptoms to tip the scales toward PCI. Among clinically stable, late-presenting patients, myocardial viability assessment and functional testing can identify yet another subgroup that may benefit from late PCI

Percutaneous Myocardial Revascularization in Late-Presenting Patients With STEMI

BACKGROUND

The optimal management of patients with ST-segment elevation myocardial infarction (STEMI) presenting late->12 hours following symptom onset-is still under debate.

OBJECTIVES

The purpose of this study was to describe characteristics, temporal trends, and impact of revascularization in a large population of latecomer STEMI patients.

METHODS

The authors analyzed the data of 3 nationwide observational studies from the FAST-MI (French Registry of Acute ST-elevation and non-ST-elevation Myocardial Infarction) program, conducted over a 1-month period in 2005, 2010, and 2015. Patients presenting between 12 and 48 hours after symptom onset were classified as latecomers.

RESULTS

A total of 6,273 STEMI patients were included in the 3 cohorts, 1,169 (18.6%) of whom were latecomers. After exclusion of patients treated with fibrinolysis and patients deceased within 2 days after admission, 1,077 patients were analyzed, of whom 729 (67.7%) were revascularized within 48 hours after hospital admission. At 30-day follow-up, all-cause death rate was significantly lower among revascularized latecomers (2.1% vs 7.2%; P < 0.001). After a median follow-up of 58 months, the rate of all-cause death was 30.4 (95% CI: 25.7-35.9) per 1,000 patient-years in the revascularized latecomers group vs 78.7 (95% CI: 67.2-92.3) per 1,000 patient-years in the nonrevascularized latecomers group (P < 0.001). In multivariate analysis, revascularization of latecomer STEMI patients was independently associated with a significant reduction of mortality occurrence during follow-up (HR: 0.65 [95% CI: 0.50-0.84]; P = 0.001).

CONCLUSIONS

Coronary revascularization of latecomer STEMI patients is associated with better short and long-term clinical outcomes.

Application of Cell, Tissue, and Biomaterial Delivery in Cardiac Regenerative Therapy

Cardiovascular diseases (CVD) are the leading cause of death around the world, being responsible for 31.8% of all deaths in 2017 (Roth, G. A. et al. The Lancet 2018, 392, 1736-1788). The leading cause of CVD is ischemic heart disease (IHD), which caused 8.1 million deaths in 2013 (Benjamin, E. J. et al. Circulation 2017, 135, e146-e603). IHD occurs when coronary arteries in the heart are narrowed or blocked, preventing the flow of oxygen and blood into the cardiac muscle, which could provoke acute myocardial infarction (AMI) and ultimately lead to heart failure and death. Cardiac regenerative therapy aims to repair and refunctionalize damaged heart tissue through the application of (1) intramyocardial cell delivery, (2) epicardial cardiac patch, and (3) acellular biomaterials. In this review, we aim to examine these current approaches and challenges in the cardiac regenerative therapy field.

Outcomes of Percutaneous Coronary Intervention Versus Optimal Medical Treatment for Chronic Total Occlusion: A Comprehensive Meta-analysis

The presence of concurrent chronic total occlusion (CTO) is a strong predictor for both short-term and long-term mortality. Successful percutaneous coronary intervention (PCI) of CTO has been associated with clinical benefit. We sought to perform a meta-analysis comparing CTO-PCI versus optimal medical therapy. PubMed, ClinicalTrials.gov, Google scholar and the Cochrane Central Register of Controlled Trials were searched for studies published from 2006 to 2019. A total of 16 studies, with 11,314 patients were included. We analyzed data on mortality, cardiac deaths, myocardial re-infarction, major adverse cardiac events, stroke, and repeat CTO-PCI using random-effects models. The odds ratios (OR) with 95% confidence interval (CI) were computed and P < 0.05 was considered as a level of significance. Compared with medical therapy alone, CTO-PCI was associated with lower mortality (OR: 0.45, CI: 0.32-0.63, P < 0.00001) and cardiac deaths (OR: 0.58, CI: 0.38-0.89, P = 0.01). These results were primarily driven by observational studies with no difference observed in randomized controlled trials. There was no significant difference in the incidence of major adverse cardiac events (OR: 0.71, CI: 0.48-1.05, P = 0.54), myocardial re-infarction (OR: 0.71, CI: 0.48-1.05, P = 0.54), stroke (OR: 0.61, CI: 0.32-1.17, P = 0.14, and repeat PCI (OR: 1.28, CI: 0.91-1.78, P = 0.16). This meta-analysis shows lower long-term mortality and cardiac deaths in CTO-PCI group as compared to OMT driven by observational studies with no difference observed in randomized controlled trials. Further randomized trials are needed to confirm these findings and evaluate long term results.

Temporal dynamics of immune response following prolonged myocardial ischemia/reperfusion with and without cyclosporine A

Understanding the dynamics of the immune response following late myocardial reperfusion is critical for the development of immunomodulatory therapy for myocardial infarction (MI). Cyclosporine A (CSA) possesses multiple therapeutic applications for MI, but its effects on the inflammation caused by acute MI are not clear. This study aimed to determine the dynamics of the immune response following myocardial ischemia/reperfusion (I/R) and the effects of CSA in a mouse model of prolonged myocardial ischemia designated to represent the human condition of late reperfusion. Adult C57BL/6 mice were subjected to 90 min of closed-chest myocardial I/R, which induced severe myocardial injury and excessive inflammation in the heart. Multicomponent analysis of the immune response caused by prolonged I/R revealed that the peak of cytokines/chemokines in the systemic circulation was synchronized with the maximal influx of neutrophils and T-cells in the heart 1 day after MI. The peak of cytokine/chemokine secretion in the infarcted heart coincided with the maximal macrophage and natural killer cell infiltration on day 3 after MI. The cellular composition of the mediastinal lymph nodes changed similarly to that of the infarcted hearts. CSA (10 mg/kg/day) given after prolonged I/R impaired heart function, enlarged the resulting scar, and reduced heart vascularization. It did not change the content of immune cells in hearts exposed to prolonged I/R, but the levels of MCP-1 and MIP-1α (hearts) and IL-12 (hearts and serum) were significantly reduced in the CSA-treated group in comparison to the untreated group, indicating alterations in immune cell function. Our findings provide new knowledge necessary for the development of immunomodulatory therapy targeting the immune response after prolonged myocardial ischemia/reperfusion.

Microvascular Alterations After Temporary Coronary Artery Occlusion: The No-Reflow Phenomenon

In experimental models of temporary coronary artery occlusion, tissue perfusion at the microvascular level remains incomplete even after patency of the infarct-related epicardial coronary artery is established, and distinct perfusion defects develop within the risk zone. This no-reflow phenomenon can be regarded as a basic cardiac response to ischemia-reperfusion. Perfusion defects observed in the clinical realm after reperfusion therapy for myocardial infarction may substantially be related to this mechanism in addition to microembolization and activation of platelets, as suggested in several recent studies. A major determinant of the amount of no-reflow seems to be infarct size itself. Reperfusion-related expansion of noreflow zones occurs within the first hours after the reopening of the coronary artery with a parallel reduction of regional myocardial flow, resulting in a potential therapeutic window. With various cardioprotective interventions, a close correlation between the size of the anatomic no-reflow and necrosis is a reproducible feature, which suggests a causal link between both entities of ischemic cardiac damage. Although vasodilating interventions failed to uncouple no-reflow zones from necrosis, the steps in the causal chain between microvascular and myocardial damage remain to be identified. On a long-term basis, tissue perfusion after ischemia-reperfusion remains markedly compromised for at least 4 weeks. Recent morphometric cardiac analyses suggested that the level of tissue perfusion after 4 weeks is a significant predictor of various indices of infarct healing, such as scar thickness, and infarct expansion index. As a consequence, improving tissue perfusion might concomitantly improve the healing process, which may provide the pathoanatomic basis for prognostic implications of no-reflow.

Clinical impacts of inhibition of renin-angiotensin system in patients with acute ST-segment elevation myocardial infarction who underwent successful late percutaneous coronary intervention

BACKGROUND

Successful percutaneous coronary intervention (PCI) of the occluded infarct-related artery (IRA) in latecomers may improve long-term survival mainly by reducing left ventricular remodeling. It is not clear whether inhibition of renin-angiotensin system (RAS) brings additional better clinical outcomes in this specific population subset.

METHODS

Between January 2008 and June 2013, 669 latecomer patients with acute ST-segment elevation myocardial infarction (STEMI) (66.2±12.1 years, 71.0% males) in Korea Acute Myocardial Infarction Registry (KAMIR) who underwent a successful PCI were enrolled. The study population underwent a successful PCI for a totally occluded IRA. They were divided into two groups according to whether they were prescribed RAS inhibitors at the time of discharge: group I (RAS inhibition, n=556), and group II (no RAS inhibition, n=113).

RESULTS

During the one-year follow-up, major adverse cardiac events (MACE), which consist of cardiac death and myocardial infarction, occurred in 71 patients (10.6%). There were significantly reduced incidences of MACE in the group I (hazard ratio=0.34, 95% confidence interval 0.199-0.588, p=0.001). In subgroup analyses, RAS inhibition was beneficial in patients with male gender, history of hypertension or diabetes mellitus, and even in patients with left ventricular ejection fraction (LVEF) ≥40%. In the baseline and follow-up echocardiographic data, benefit in changes of LVEF and left ventricular end-systolic volume was noted in group I.

CONCLUSIONS

In latecomers with STEMI, RAS inhibition improved long-term clinical outcomes after a successful PCI, even in patients with low risk who had relatively preserved LVEF.

OPC-28326, a selective peripheral vasodilator with angiogenic activity, mitigates postinfarction cardiac remodeling

Although OPC-28326, 4-(N-methyl-2-phenylethylamino)-1-(3,5-dimethyl-4-propionyl-aminobenzoyl) piperidine hydrochloride monohydrate, was developed as a selective peripheral vasodilator with α2-adrenergic antagonist properties, it also reportedly exhibits angiogenic activity in an ischemic leg model. The purpose of this study was to examine the effect of OPC-28326 on the architectural dynamics and function of the infarcted left ventricle during the chronic stage of myocardial infarction. Myocardial infarction was induced in male C3H/He mice, after which the mice were randomly assigned into two groups: a control group receiving a normal diet and an OPC group whose diet contained 0.05% OPC-28326. The survival rate among the mice (n = 18 in each group) 4 wk postinfarction was significantly greater in the OPC than control group (83 vs. 44%; P < 0.05), and left ventricular remodeling and dysfunction were significantly mitigated. Histologically, infarct wall thickness was significantly greater in the OPC group, due in part to an abundance of nonmyocyte components, including blood vessels and myofibroblasts. Five days postinfarction, Ki-67-positive proliferating cells were more abundant in the granulation tissue in the OPC group, and there were fewer apoptotic cells. These effects were accompanied by activation of myocardial Akt and endothelial nitric oxide synthase. Hypoxia within the infarct issue, assessed using pimonidazole staining, was markedly attenuated in the OPC group. In summary, OPC-28326 increased the nonmyocyte population in infarct tissue by increasing proliferation and reducing apoptosis, thereby altering the tissue dynamics such that wall stress was reduced, which might have contributed to a mitigation of postinfarction cardiac remodeling and dysfunction.

Late percutaneous coronary intervention prevents left ventricular remodeling and improves clinical outcomes in patients with ST-elevation myocardial infarction

BACKGROUND

The optimal strategy for treating late presenters of ST-elevation myocardial infarction (STEMI) remains uncertain.

HYPOTHESIS

percutaneous coronary intervention (PCI) has a favorable effect on left ventricular (LV) remodeling and clinical outcomes in late presenters of STEMI.

METHODS

Patients with STEMI who were hospitalized between 2009 and 2011 at 7 PCI-capable hospitals in China were selected. Cardiac characteristics were reassessed by echocardiography between August 2013 and January 2014. The clinical endpoints were evaluated during a median follow-up period of 36 months.

RESULTS

1090 patients who either underwent late PCI (n = 786) or received standard medical therapy alone (n = 304) was analyzed. Left ventricular remodeling was more pronounced in the conservative-treatment group. Logistic regression revealed that late PCI was independently and negatively correlated with LV remodeling (odds ratio: 0.356, 95% confidence interval [CI]: 0.251-0.505, P < 0.001). Kaplan-Meier analysis showed the lower risks of major adverse cardiovascular events (MACE), all-cause death, and rehospitalization for heart failure in the late-PCI group. Multivariate Cox regression revealed that late PCI was significantly associated with lower risks for MACE, all-cause death, and rehospitalization for heart failure both in all patients (hazard ratio [HR]: 0.507, 95% CI: 0.412-0.625, P < 0.001; HR: 0.419, 95% CI: 0.314-0.559, P < 0.001; and HR: 0.583, 95% CI: 0.379-0.896, P = 0.014, respectively) and in the matched patients (HR: 0.466, 95% CI: 0.358-0.607, P < 0.001; HR: 0.398, 95% CI: 0.277-0.571, P < 0.001; and HR: 0.498, 95% CI: 0.283-0.878, P = 0.016, respectively) by propensity-score analysis.

CONCLUSIONS

Late-PCI strategy prevents LV remodeling and improves clinical outcomes in STEMI patients compared with conservative strategies.

Left ventricular remodeling after acute myocardial infarction: the influence of viability and revascularization - an echocardiographic substudy of the VIAMI-trial

BACKGROUND

Viability seems to be important in preventing ventricular remodeling after acute myocardial infarction (AMI). We investigated the influence of viability, as demonstrated with low-dose dobutamine echocardiography, and the role of early revascularization on the process of left ventricular (LV) remodeling after AMI.

METHODS

We retrospectively investigated 224 patients who were initially included in the viability-guided angioplasty after acute myocardial infarction-trial (VIAMI-trial). Patients in the VIAMI-trial did not undergo a primary or rescue percutaneous coronary intervention and were stable in the early in-hospital phase. Patients underwent viability testing within 72 hours after AMI. Patients with viability were randomized to an invasive strategy or an ischemia-guided strategy. Follow-up echocardiography was performed at a mean of 205 days. In this echocardiographic substudy, patients were divided into three new groups: group 1, viable and revascularized before follow-up echocardiogram; group 2, viable, but medically treated; and group 3, non-viable patients.

RESULTS

Group 1 showed preservation of LV volume indices. The ejection fraction (EF) increased significantly from 54.0% to 57.5% (P = 0.047). Group 2 showed a significant increase in LV volume indices with no improvement in EF (53.3% versus 53.0%, P = 0.86). Group 3 showed a significant increase in LV volume indices, with a decrease in EF from 53.5% to 49.1% (P = 0.043). Multivariate logistic regression analysis indicated the number of viable segments and revascularization during follow-up as independent predictors for EF improvement, especially in patients with lower EF at baseline.

CONCLUSION

Viability early after AMI is associated with improvement in LV function after revascularization. When viable myocardium is not revascularized, the LV tends to remodel with increased LV volumes, without improvement of EF. Absence of viability results in ventricular dilatation and deterioration of EF, irrespective of revascularization status.

TRIAL REGISTRATION

NCT00149591 (assigned: 6 September 2005).

Left ventricular remodeling after late revascularization correlates with baseline viability

The ideal management of stable patients who present late after acute ST-elevation myocardial infarction (STEMI) is still a matter of conjecture. We hypothesized that the extent of improvement in left ventricular function after successful revascularization in this subset was related to the magnitude of viability in the infarct-related artery territory. However, few studies correlate the improvement of left ventricular function with the magnitude of residual viability in patients who undergo percutaneous coronary intervention in this setting. In 68 patients who presented later than 24 hours after a confirmed first STEMI, we performed resting, nitroglycerin-enhanced, technetium-99m sestamibi single-photon emission computed tomography-myocardial perfusion imaging (SPECT-MPI) before percutaneous coronary intervention, and again 6 months afterwards. Patients whose baseline viable myocardium in the infarct-related artery territory was more than 50%, 20% to 50%, and less than 20% were divided into Groups 1, 2, and 3 (mildly, moderately, and severely reduced viability, respectively). At follow-up, there was significant improvement in end-diastolic volume, end-systolic volume, and left ventricular ejection fraction in Groups 1 and 2, but not in Group 3. We conclude that even late revascularization of the infarct-related artery yields significant improvement in left ventricular remodeling. In patients with more than 20% viable myocardium in the infarct-related artery territory, the extent of improvement in left ventricular function depends upon the amount of viable myocardium present. The SPECT-MPI can be used as a guide for choosing patients for revascularization.

Evaluation of experimental myocardial infarction models via electromechanical mapping and magnetic resonance imaging

The diagnostic characteristics of electromechanical mapping (EMM) were evaluated in porcine myocardial infarction (MI) models with the parallel application of cardiac magnetic resonance imaging (cMRI) from the aspect of different pathophysiology and localization. Balloon occlusion in the left anterior descending coronary artery (LAD balloon group) or coil deployment in the LAD (LAD coil group) or circumflex artery (Cx coil group) was applied percutaneously in 16 domestic pigs. Regional left ventricular viability data were captured via cMRI and EMM. The unipolar voltage (UV) value was significantly decreased in segments containing transmural and subendocardial late enhancement compared with viable segments in the LAD balloon, LAD coil, and Cx coil groups. Receiver operating characteristic analysis revealed area under the curve values of 0.809 and 0.691 in the LAD infarct territory, and 0.864 and 0.855 in the Cx infarct territory for the UV compared with cMRI viability results as transmural late enhancement or viable tissue and subendocardial late enhancement or viable tissue, respectively. In conclusion, the UV value detected the presence of scar tissue with differential transmural extent and which represented proper diagnostic features both in the reperfused and nonreperfused models. This data could provide additional benefit in the clinical use of EMM for diagnostic purposes.

Overview of large animal myocardial infarction models (review)

There are several experimental models for the in vivo investigation of myocardial infarction (MI) in small (mouse, rat) and large animals (dog, pig, sheep and baboons). The application of large animal models raises ethical concerns, the design of experiments needs longer follow-up times, requiring proper breeding and housing conditions, therefore resulting in higher cost, than in vitro or small animal studies. On the other hand, the relevance of large animal models is very important, since they mostly resemble to human physiological and pathophysiological processes. The first main difference among MI models is the method of induction (open or closed chest, e.g. surgical or catheter based); the second main difference is the presence or absence of reperfusion. The former (i.e. reperfused MI) allows the investigation of reperfusion injury and new catheter based techniques during percutaneous coronary interventions, while the latter (i.e. nonreperfused MI) serves as a traditional coronary occlusion model, to test the effects of new pharmacological agents and biological therapies, as cell therapy. The reperfused and nonreperfused myocardial infarction has different outcomes, regarding left ventricular function, remodelling, subsequent heart failure, aneurysm formation and mortality. Our aim was to review the literature and report our findings regarding experimental MI models, regarding the differences among species, methods, reproducibility and interpretation.

Hyperoxia and transforming growth factor β1 signaling in the post-ischemic mouse heart

AIMS

Following ischemic injury, myocardial healing and remodeling occur with characteristic myofibroblast trans-differentiation and scar formation. The current study tests the hypothesis that hyperoxia and nitric oxide (NO) regulate TGF-β1 signaling in the post-ischemic myocardium.

MAIN METHODS

C57BL/6 wild-type (WT), endothelial and inducible nitric oxide synthase knockout (eNOS(-/-) and iNOS(-/-)) mice were subjected to 30-min left anterior descending coronary artery occlusion followed by reperfusion. Myocardial tissue oxygenation was monitored with electron paramagnetic resonance oximetry. Protein expressions of TGF-β1, receptor-activated small mothers against decapentaplegic homolog (Smad), p21 and α-smooth muscle actin (α-SMA) were measured with enzyme-linked immunosorbent assay (ELISA), Western immunoblotting, and immunohistochemical staining.

KEY FINDINGS

There was a hyperoxic state in the post-ischemic myocardial tissue. Protein expressions of total and active TGF-β1, p-Smad2/3 over t-Smad2/3 ratio, p21, and α-SMA were significantly increased in WT mice compared to Sham control. Knockout of eNOS or iNOS further increased protein expression of these signals. The expression of α-SMA was more abundant in the infarct of eNOS(-/-) and iNOS(-/-) mice than WT mice. A protein band indicating nitration of TGF-β type-II receptor (TGFβRII) was observed from WT heart. Carbogen (95% O2 plus 5% CO2) treatment increased the ratio of p-Smad2/t-Smad2, which was inhibited by 10006329 EUK (EUK134) and sodium nitroprusside (SNP). In conclusion, hyperoxia up-regulated and NO/ONOO(-) inhibited cardiac TGF-β1 signaling and myofibroblast trans-differentiation.

SIGNIFICANCE

These findings may provide new insights in myocardial infarct healing and repair.

Myocardial ischemia, reperfusion, and infarction in chronically instrumented, intact, conscious, and unrestrained mice

In the United States alone, the National Heart, Lung, and Blood Institute (NHLBI) has invested several hundred million dollars in pursuit of myocardial infarct-sparing therapies. However, due largely to methodological limitations, this investment has not produced any notable clinical application or cardioprotective therapy. Among the major methodological limitations is the reliance on animal models that do not mimic the clinical situation. In this context, the limited use of conscious animal models is of major concern. In fact, whenever possible, studies of cardiovascular physiology and pathophysiology should be conducted in conscious, complex models to avoid the complications associated with the use of anesthesia and surgical trauma. The mouse has significant advantages over other experimental models for the investigation of infarct-sparing therapies. The mouse is inexpensive, has a high throughput, and presents the ability of one to create genetically modified models. However, successful infarct-sparing therapies in anesthetized mice or isolated mouse hearts may not be successful in more complex models, including conscious mice. Accordingly, a conscious mouse model of myocardial ischemia and reperfusion has the potential to be of major importance for advancing the concepts and methods that drive the development of infarct-sparing therapies. Therefore, we describe, for the first time, the use of an intact, conscious, and unrestrained mouse model of myocardial ischemia-reperfusion and infarction. The conscious mouse model permits occlusion and reperfusion of the left anterior descending coronary artery in an intact, complex model free of the confounding influences of anesthetics and surgical trauma. This methodology may be adopted for advancing the concepts and ideas that drive cardiovascular research.

Ischemia/Infarction

Myocardial infarction (MI) accounts for most incidences of heart failure (HF) and low ejection fraction. Evidence suggests that acute MI leads to early cardiac remodeling, with changes in ventricular geometry and structure that in turn lead to a vicious cycle of ventricular dilation, increased wall stress, hypertrophy and more ventricular dilation and dysfunction, and worsening of HF. The early geometric and structural changes contribute to early mechanical complications and subsequent progressive ventricular remodeling and the development of chronic HF. A clear understanding of the underlying mechanisms is helpful in developing optimal preventive and therapeutic strategies for HF.

Peri-interventional coronary vasomotion

A percutaneous coronary intervention (PCI) is a unique condition to study the effects of ischemia and reperfusion in patients with severe coronary atherosclerosis when coronary vasomotor function is compromised by loss of endothelial and autoregulatory vasodilation. We studied the effects of intracoronary non-selective α-, as well as selective α(1)- and α(2)-blockade in counteracting the observed vasoconstriction in patients with stable and unstable angina and in patients with acute myocardial infarction. Coronary vasoconstriction in our studies was a diffuse phenomenon and involved not only the culprit lesion but also vessels with angiographically not visible plaques. Post-PCI vasoconstriction was reflected by increased coronary vascular resistance and associated with decreased LV-function. α (1)-Blockade with urapidil dilated epicardial coronary arteries, improved coronary flow reserve and counteracted LV dysfunction. Non-selective α-blockade with phentolamine induced epicardial and microvascular dilation, while selective α(2)-blockade with yohimbine had only minor vasodilator and functional effects. Intracoronary α-blockade also attenuated the no-reflow phenomenon following primary PCI. This article is part of a Special Issue entitled "Coronary Blood Flow".

Does ST resolution achieved via different reperfusion strategies (fibrinolysis vs percutaneous coronary intervention) have different prognostic meaning in ST-elevation myocardial infarction? A systematic review

OBJECTIVE

We perform a systematic review to discern if ST resolution achieved via percutaneous coronary intervention (PCI) has a different meaning to that achieved via fibrinolysis.

BACKGROUND

Resolution of ST-segment elevation in acute myocardial infarction has been widely used as a surrogate for treatment success. A recent randomized study suggested that after primary PCI, the prognostic significance of ST resolution may have been overemphasized.

METHODS

Using the MEDLINE, COCHRANE, EMBASE, and PUBMED databases to search for the relevant papers, we analyze the data with a new ST-resolution score. ST-resolution groups of <30%, 30% to < 70%, and ≥ 70% are given scores of 1, 2, and 3 respectively, whereas ST-resolution groups reported as < 50% are scored as 1.5, and ≥ 50% scored as 2.5.

RESULTS

We identify 18 fibrinolysis cohorts (32,341 patients) and 5 PCI cohorts (1,913 patients). The mean ST-resolution score weighted for the number of patients in each cohort is 1.87 ± 0.15 for PCI and 1.66 ± 0.20 for fibrinolysis (P < .001). The raw combined 30-day mortality is 4.9% with fibrinolysis and 4.3% with PCI (P = .452 by Poisson regression). There is a linear relationship with lower 30-day mortality associated with higher ST-resolution score. The regression line for the PCI cohorts almost overlaps with that from the fibrinolysis cohorts. On multivariate regression, only ST-resolution score is significant in predicting 30-day mortality. When tested, the interaction term (treatment group × ST resolution score) is never a significant predictor (P > .25 in all models).

CONCLUSION

ST resolution after different reperfusion therapies has similar prognostic meaning.

Long-term effects of invasive treatment in patients with a post-thrombolytic Q-wave myocardial infarction

OBJECTIVES

The aim of the present study was to assess the effect of a deferred invasive treatment strategy on long-term outcome in patients with a post-thrombolytic Q-wave myocardial infarction and inducible myocardial ischemia.

DESIGN

Patients (N=751) with post-thrombolytic Q-wave myocardial infarction and inducible ischemia (angina pectoris or silent myocardial ischemia) were randomized to a deferred invasive treatment (balloon angioplasty or coronary bypass surgery) or medical treatment. Vital status and non-fatal cardiac events defined as hospitalization caused by acute cardiac events were recorded for a median of 11.4 years.

RESULTS

Survival was significantly improved in patients receiving invasive treatment compared to patients treated medically (hazard ratio 0.85 (95% confidence limits 0.73-0.99), p=0.034). Subgroup analysis showed a reduction of non-fatal cardiac events and improved survival among the patients with post-infarction angina pectoris and not among the patients with silent myocardial ischemia.

CONCLUSIONS

A deferred invasive treatment strategy improves survival compared to medical treatment in patients with inducible myocardial ischemia after a post-thrombolytic Q-wave myocardial infarction.

Timing of nonemergent coronary artery bypass grafting and mortality after non-ST elevation acute coronary syndrome

BACKGROUND

The purpose of this study was to determine the association between time to coronary artery bypass grafting (CABG) and mortality among patients admitted with non-ST elevation acute coronary syndrome (NSTEACS). Patients are increasingly being referred for CABG soon after NSTEACS, although few data exist to guide the optimal timing of bypass surgery.

METHODS

We identified a cohort of all patients who underwent nonemergent CABG within 60 days of hospitalization for NSTEACS in the province of Alberta, Canada, from 2000 to 2004. Time from admission to CABG was categorized as early (2-7 days), intermediate (8-14 days), or late (15-60 days-reference group). The primary outcome was mortality occurring within 30 days of surgery.

RESULTS

Of the total cohort of 1,454 patients, 213 (14.6%) underwent early, 637 (43.8%) underwent intermediate, and 707 (48.6%) underwent late CABG surgery. In the final adjusted model time to CABG was not statistically significant as an independent predictor of short-term mortality. Compared to late CABG, there was a nonsignificant increased risk of mortality for those undergoing early (hazard ratio 2.36, 95% CI 0.72-7.76) and intermediate (hazard ratio 1.68, 95% CI 0.76-3.72) CABG surgery.

CONCLUSIONS

Time from admission to CABG was not associated with an increased risk of short-term mortality. However, there was a trend toward increased mortality with early CABG, and this study does not exclude the presence of a modest risk association between timing of CABG and short-term mortality.

Infarct evolution in man studied in patients with first-time coronary occlusion in comparison to different species - implications for assessment of myocardial salvage

BACKGROUND

The time course of infarct evolution, i.e. how fast myocardial infarction (MI) develops during coronary artery occlusion, is well known for several species, whereas no direct evidence exists on the evolution of MI size normalized to myocardium at risk (MaR) in man. Despite the lack of direct evidence, current literature often refers to the "golden hour" as the time during which myocardial salvage can be accomplished by reperfusion therapy. Therefore, the aim of the present study was to investigate how duration of myocardial ischemia affects infarct evolution in man in relation to previous animal data. Consecutive patients with clinical signs of acute myocardial ischemia were screened and considered for enrollment. Particular care was taken to assure uniformity of the patients enrolled with regard to old MI, success of revascularization, collateral flow, release of biochemical markers prior to intervention etc. Sixteen patients were ultimately included in the study. Myocardium at risk was assessed acutely by acute myocardial perfusion single photon emission computed tomography (MPS) and by T2 imaging (T2-STIR) cardiovascular magnetic resonance (CMR) after one week in 10 of the 16 patients. Infarct size was measured by late gadolinium enhancement (LGE) at one week.

RESULTS

The time to reach 50% MI of the MaR (T50) was significantly shorter in pigs (37 min), rats (41 min) and dogs (181 min) compared to humans (288 min). There was no significant difference in T50 when using MPS compared to T2-STIR (p = 0.53) for assessment of MaR (288 +/- 23 min vs 310 +/- 22 min, T50 +/- standard error). The transmural extent of MI increased progressively as the duration of ischemia increased (R2 = 0.56, p < 0.001).

CONCLUSION

This is the first study to provide direct evidence of the time course of acute myocardial infarct evolution in relation to MaR in man with first-time MI. Infarct evolution in man is significantly slower than in pigs, rats and dogs. Furthermore, infarct evolution assessments in man are similar when using MPS acutely and T2-STIR one week later for determination of MaR, which significantly facilitates future clinical trials of cardioprotective therapies in acute coronary syndrome by the use of CMR.

Beneficial effect of reperfusion therapy beyond the preservation of left ventricular function in patients with acute ST-segment elevation myocardial infarction

BACKGROUND

Reperfusion therapy has been shown to improve mortality in patients with acute ST-segment elevation myocardial infarction. However, in randomized clinical trials there was only a modest improvement in left ventricular ejection fraction with reperfusion therapy, despite a larger improvement in mortality.

METHODS

In the prospective MITRA-Plus registry we compared 1-year mortality of inhospital survivors of ST-segment elevation myocardial infarction (STEMI) divided into nine groups with preserved (>55%), moderately reduced (41-55%) and severely reduced (≤40%) left ventricular ejection fraction (LVEF) and treated with no early reperfusion therapy, fibrinolysis or primary percutaneous coronary intervention (PCI) within 24 h after admission.

RESULTS

A total of 5867 patients were included in this analysis, 1026 (18%) without early reperfusion, 2462 (42%) with fibrinolysis and 2379 (40%) with primary PCI. After adjustment for confounding variables in a propensity score analysis, reperfusion therapy (Odds ratio and 95% CI: 0.27, 0.15-0.48; 0.50, 0.32-0.79; 0.64, 0.44-0.93), fibrinolysis (Odds ratio and 95% CI: 0.27, 0.14-0.52; 0.58, 0.35-0.95; 0.60, 0.39-0.93) and primary PCI (Odds ratio and 95% CI: 0.22, 0.11-0.44; 0.34, 0.19-0.59; 0.56, 0.36-0.88) remained independent predictors of survival in comparison to no reperfusion therapy in the patients with preserved, moderately reduced and severely reduced LVEF, respectively.

CONCLUSIONS

These results suggest a beneficial effect of early reperfusion therapy beyond the preservation of left ventricular function, however the mechanisms need further study.

Association of door-to-balloon time and mortality in patients admitted to hospital with ST elevation myocardial infarction: national cohort study

OBJECTIVE

To evaluate the association between door-to-balloon time and mortality in hospital in patients undergoing primary percutaneous coronary intervention for ST elevation myocardial infarction to assess the incremental mortality benefit of reductions in door-to-balloon times of less than 90 minutes.

DESIGN

Prospective cohort study of patients enrolled in the American College of Cardiology National Cardiovascular Data Registry, 2005-6.

SETTING

Acute care hospitals.

PARTICIPANTS

43 801 patients with ST elevation myocardial infarction undergoing primary percutaneous coronary intervention.

MAIN OUTCOME MEASURE

Mortality in hospital.

RESULTS

Median door-to-balloon time was 83 minutes (interquartile range 6-109, 57.9% treated within 90 minutes). Overall mortality in hospital was 4.6%. Multivariable logistic regression models with fractional polynomial models indicated that longer door-to-balloon times were associated with a higher adjusted risk of mortality in hospital in a continuous non-linear fashion (30 minutes=3.0%, 60 minutes=3.5%, 90 minutes=4.3%, 120 minutes=5.6%, 150 minutes=7.0%, 180 minutes=8.4%, P<0.001). A reduction in door-to-balloon time from 90 minutes to 60 minutes was associated with 0.8% lower mortality, and a reduction from 60 minutes to 30 minutes with a 0.5% lower mortality.

CONCLUSION

Any delay in primary percutaneous coronary intervention after a patient arrives at hospital is associated with higher mortality in hospital in those admitted with ST elevation myocardial infarction. Time to treatment should be as short as possible, even in centres currently providing primary percutaneous coronary intervention within 90 minutes.

Persistent reservations against contradicted percutaneous coronary intervention indications: citation content analysis

BACKGROUND

Two large trials, Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) and Occluded Artery Trial (OAT), found no benefits of percutaneous coronary intervention (PCI) versus optimal medical therapy in chronic stable coronary artery disease and chronic total occlusion.

METHODS

We examined the stance of articles citing COURAGE and OAT to determine whether some authors continue to defend PCI despite this evidence, what persisting counterarguments are raised to express reservations, and whether specific characteristics of the citations are associated with reservations. We evaluated all citing articles entered in the Web of Science until February 1, 2008. Specific characteristics were recorded for each eligible citation, and a citation content analysis was performed. Counterarguments were categorized on participants, interventions, comparisons, and outcomes.

RESULTS

Of 54 articles citing COURAGE and 33 articles citing OAT, 10 (19%) and 5 (15%), respectively, had an overall reserved stance. Alluded reservations included lack of power, eroded effects from crossover, selective inclusion and exclusion of specific types of patients, suboptimal clinical setting, use of bare-metal stents, suspiciously good results in the conservative treatment arm, and suboptimal outcome choices or definitions. Reserved articles were more likely than unreserved ones to have an interventional cardiologist as corresponding author (odds ratio 5.2, 95% confidence interval 1.6-17.1; P = .007) and to be commentaries focusing on one of these trials (odds ratio 3.3, 95% confidence interval 1.0-11.0; P = .05).

CONCLUSIONS

Despite strong randomized evidence, a fraction of the literature, mostly corresponded by interventional cardiologists, continues to raise reservations about recently contradicted indications of PCI.

Severity of residual stenosis of infarct-related lesion and left ventricular function after single-vessel anterior wall myocardial infarction: implication of ST-segment elevation in lead aVL of the admission electrocardiograms

BACKGROUND

The relationship between the severity of chronic-phase stenosis of infarct-related lesions (IRLs) and chronic left ventricular function in anterior acute myocardial infarctions (AMI) has not been adequately investigated.

HYPOTHESIS

This study investigated whether ST elevation in lead aVL of admission electrocardiogram (ECG) would be a determinant factor of the relationship between the severity of stenosis of the IRL and chronic left ventricular function after anterior wall AMI.

METHODS

One month after AMI, the IRL was evaluated by coronary angiography in 98 patients with anterior AMI, and left ventricular ejection fraction (LVEF) was determined using multigated radionuclide angiocardiography. Patients were classified according to the severity of the IRL: patients with 100% occlusion (Group O), patients with 90 to 99% stenosis (Group H), and patients with < or =75% stenosis (Group L). Patients with ST elevation > or =0.1 mV in the aVL lead on their admission ECG were included in the ST-elevation group, and those with ST elevation <0.1 mV were included in the non-ST-elevation group.

RESULTS

The LVEF was greater in the non-ST-elevation group than in the ST-elevation group (p<0.0001), and the LVEF in a whole group as follows: Group L LVEF>Group H LVEF>Group O LVEF (p = 0.0160). In the ST-elevation group, LVEF was higher in Group L than in the other groups (p = 0.0251). There were three independent predictors of a reduced LVEF: ST-elevation in aVL [odds ratio (OR): 3.38, p = 0.0044], IRL stenosis > or =90% (OR: 2.90, p = 0.0044), and the IRL occurring in the left anterior descending artery proximal to the first diagonal branch (OR: 6.31, p = 0.0024).

CONCLUSION

Left ventricular function was preserved, regardless of the severity of residual stenosis, in patients without ST elevation in aVL if the IRL was not totally occluded. In patients with ST elevation in aVL, LVEF was lower in patients with more severe stenosis, even if the IRL was patent.

Predictors of early and late ventricular remodeling after acute myocardial infarction

BACKGROUND

The determinants of the early and late stages of the ventricular remodeling process after infarction are not well defined.

HYPOTHESIS

The study was undertaken to evaluate the factors that condition the time course of left ventricular dilation during the first 6 months after infarction.

METHODS

The study group consisted of 74 patients with a first intermediate-large (> or = 4 Q waves) acute myocardial infarction. Contrast left ventricular and coronary angiograms were performed at 7 +/- 1 and 175 +/- 25 days after infarction. Left ventricular volumes, regional function and infarction artery status were quantified. Percutaneous transluminal coronary angioplasty (PTCA) was performed in the early angiogram in 31 patients.

RESULTS

In the early angiogram, 13 patients showed ventricular remodeling (end-diastolic volume > 90 ml/m2). A larger extent of dysfunction was the only predictor (p < 0.002) of early remodeling. At 6 months, a smaller, early end-diastolic volume (p < 0.0001) and a poorer regional function recovery (p < 0.05) were independently related to late diastolic enlargement, and a poorer regional function recovery (p < 0.0001) and a smaller, early end-systolic volume (p < 0.009) were independently related to late systolic enlargement. One patient with compared with 20 patients without early remodeling (p < 0.04) presented with late remodeling (increment of the end-diastolic volume > 20% at 6 months). In patients with early remodeling, the end-diastolic volume did not change significantly (101 +/- 13 vs. 94 +/- 22 ml/m2, NS) at 6 months; despite this, they maintained larger diastolic volumes than patients with late remodeling (81 +/- 12 ml/m2, p < 0.04) at 6 months. Infarction artery status did not influence the evolution of ventricular volumes and regional function.

CONCLUSIONS

(1) A large infarct size is the main determinant of postinfarction remodeling. (2) Such infarct size-dependent ventricular dilation occurs early and does not tend to increase in late stage; in contrast, some cases of intermediate-large size infarcts without early remodeling exhibit late remodeling associated with a poor late recovery of regional function. (3) Recovery of regional function (indicating myocardial viability) rather than infarction artery status plays a role in the late ventricular remodeling process.

Electrophysiological effects of late percutaneous coronary intervention for infarct-related coronary artery occlusion: the Occluded Artery Trial-Electrophysiological Mechanisms (OAT-EP)

BACKGROUND

The Occluded Artery Trial-Electrophysiological Mechanisms (OAT-EP) tested the hypothesis that opening a persistently occluded infarct-related artery by percutaneous coronary intervention and stenting (PCI) after the acute phase of myocardial infarction compared with optimal medical therapy alone reduces markers of vulnerability to ventricular arrhythmias.

METHODS AND RESULTS

Between April 2003 and December 2005, 300 patients with an occluded native infarct-related artery 3 to 28 days (median, 12 days) after myocardial infarction were randomized to PCI or optimal medical therapy. Ten-minute digital Holter recordings were obtained before randomization, at 30 days, and at 1 year. The primary end point was the change in alpha1, a nonlinear heart rate variability parameter, between baseline and 1 year. Major secondary end points were the changes in the filtered QRS duration on the signal-averaged ECG and variability in T-wave morphology (T-wave variability) between baseline and 1 year. There were no significant differences in the changes in alpha1 (-0.04; 95% CI, -0.12 to 0.04), filtered QRS (2.2 ms; 95% CI, -1.4 to 5.9 ms), or T-wave variability (3.0 microV; 95% CI, -4.8 to 10.7 microV) between the PCI and medical therapy groups (medical therapy change minus PCI change). Multivariable analysis revealed that the results were unchanged after adjustment for baseline clinical variables and medication treatments during the Holter recordings.

CONCLUSIONS

PCI with stenting of a persistently occluded infarct-related artery during the subacute phase after myocardial infarction compared with medical therapy alone had no significant effect on changes in heart rate variability, the time-domain signal-averaged ECG, or T-wave variability during the first year after myocardial infarction. These findings are consistent with the lack of clinical benefit, including no reduction in sudden death, with PCI for stable patients with persistently occluded infarct-related arteries after myocardial infarction in the main OAT.

Benefits of reperfusion beyond infarct size limitation

The most critical determinant of prognosis in patients with acute myocardial infarction (MI) is infarct magnitude, which can be established within several hours of an attack. The importance of the subsequent healing process is not negligible, however. In fact, much experimental and clinical evidence suggests that late reperfusion of the infarct-related coronary artery--i.e. at times too late to salvage the myocardium within the area at risk-is beneficial for reducing left ventricular remodelling and decreasing mortality ('open artery hypothesis'). For instance, one recent study highlighted the beneficial effects of late reperfusion therapy on the infarct tissue cell dynamics following acute MI. Nonetheless, several recent large, randomized clinical trials have failed to provide evidence of such benefits, refuting the clinical efficacy of late reperfusion. In addition, they also underscore the need for revised clinical studies in which there is less heterogeneity in the timing of reperfusion and in the initial infarct size, as well as the need for sustained patency of the recanalized artery. This review focuses on the effects of late reperfusion on the pathophysiology of MI in the context of the infarct tissue dynamics and clinical outcomes. We also discuss the issues that need to be resolved to improve clinical application.

Lack of benefit from percutaneous intervention of persistently occluded infarct arteries after the acute phase of myocardial infarction is time independent: insights from Occluded Artery Trial

AIMS

The Occluded Artery Trial (OAT) (n = 2201) showed no benefit for routine percutaneous intervention (PCI) (n = 1101) over medical therapy (MED) (n = 1100) on the combined endpoint of death, myocardial infarction (MI), and class IV heart failure (congestive heart failure) in stable post-MI patients with late occluded infarct-related arteries (IRAs). We evaluated the potential for selective benefit with PCI over MED for patients enrolled early in OAT.

METHODS AND RESULTS

We explored outcomes with PCI over MED in patients randomized to the </=3 calendar days and </=7 calendar days post-MI time windows. Earlier, times to randomization in OAT were associated with higher rates of the combined endpoint (adjusted HR 1.04/day: 99% CI 1.01-1.06; P < 0.001). The 48-month event rates for </=3 days, </=7 days post-MI enrolled patients were similar for PCI vs. MED for the combined and individual endpoints. There was no interaction between time to randomization defined as a continuous (P = 0.55) or categorical variable with a cut-point of 3 days (P = 0.98) or 7 days (P = 0.64) post-MI and treatment effect.

CONCLUSION

Consistent with overall OAT findings, patients enrolled in the </=3 day and </=7 day post-MI time windows derived no benefit with PCI over MED with no interaction between time to randomization and treatment effect. Our findings do not support routine PCI of the occluded IRA in trial-eligible patients even in the earliest 24-72 h time window.

Why physicians favor use of percutaneous coronary intervention to medical therapy: a focus group study

BACKGROUND

Percutaneous coronary intervention (PCI) is performed in many patients with stable coronary artery disease, despite evidence of little clinical benefit over optimal medical therapy.

OBJECTIVE

To examine physicians' beliefs, practices, and decision-making regarding elective PCI.

DESIGN

Six focus groups, three with primary care physicians and three with cardiologists. Participants discussed PCI using hypothetical case scenarios. Transcripts were analyzed using grounded theory, and commonly expressed themes regarding the decision-making pathway to PCI were identified.

PARTICIPANTS

Twenty-eight primary care physicians and 20 interventional and non-interventional cardiologists in Butte County, Orange County, and San Francisco Bay Area, California, in 2006.

RESULTS

A number of factors led primary care physicians to evaluate non-symptomatic or minimally symptomatic patients for coronary artery disease and refer them to a cardiologist. The use of screening tests often led to additional testing and referral, as well as fear of missing a coronary stenosis, perceived patient expectations, and medicolegal concerns. The end result was a cascade such that any positive test would generally lead to the catheterization lab, where an "oculostenotic reflex" made PCI a virtual certainty.

CONCLUSIONS

The widespread use of PCI in patients with stable coronary artery disease--despite evidence of little benefit in outcomes over medical therapy--may in part be due to psychological and emotional factors leading to a cascade effect wherein testing leads inevitably to PCI. Determining how to help physicians better incorporate evidence-based medicine into decision-making has important implications for patient outcomes and the optimal use of new technologies.

Management of chronic coronary disease: is the pendulum returning to equipoise?

Over the last 3 decades, our ability to mechanically dilate obstructive coronary arterial stenoses has fundamentally altered our approach to managing patients with coronary artery disease (CAD). The result has been a swing from an initial pharmacologic approach to anatomically driven revascularization. An accumulation of clinical evidence provides strong support for such intervention in acute coronary syndromes (ACS). In stable CAD, dilative therapy was believed to be superior based on the assumption that high-risk coronary anatomy or myocardial ischemia increases the risk of future death and myocardial infarction. However, there have been major advances in our understanding of the pathophysiology of ACS and the recognition of the significance of predisposing non-flow-limiting coronary stenoses prone to rupture, as well as increasing insight into plaque and patient vulnerability. This improved understanding of the disease has led to the more aggressive use of appropriately targeted pharmacologic agents and an evolution in what constitutes optimal medical therapy (OMT). Data from recent studies, such as the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial, support the concept that in patients with stable CAD, OMT alone in this day and age compares favorably with a therapeutic strategy combining OMT with mechanical intervention. Thus, the treatment pendulum may be swinging back to the understanding that "best practice" today requires the judicious use of interventional and medical therapies in the appropriate patient population.

Survival and cardiac remodeling benefits in patients undergoing late percutaneous coronary intervention of the infarct-related artery: evidence from a meta-analysis of randomized controlled trials

OBJECTIVES

Our purpose was to perform a systematic review and meta-analysis of randomized trials comparing percutaneous coronary intervention (PCI) of the infarct-related artery (IRA) with medical therapy in patients randomized >12 h after acute myocardial infarction (AMI).

BACKGROUND

There is ongoing uncertainty about the risk-benefit ratio of late PCI in stable patients with AMI.

METHODS

PubMed, CENTRAL, and other databases were searched (July 2007). Studies were included if they compared PCI with medical management and randomized patients >12 h and up to 60 days after AMI, and were excluded if patients were hemodynamically unstable. Odds ratios (ORs) were pooled for dichotomous outcomes, with all-cause mortality as the primary end point. Left cardiac remodeling parameters were also pooled with generic inverse-variance weighting.

RESULTS

We retrieved 10 studies that enrolled 3,560 patients, with median time from AMI to randomization of 12 days (range 1 to 26 days), and follow-up of 2.8 years (42 days to 10 years). Randomization allocated 1,779 subjects to PCI and 1,781 to medical treatment. There were 112 (6.3%) and 149 (8.4%) deaths in the 2 groups, respectively, yielding significantly improved survival in the PCI group (OR 0.49 [95% confidence interval (CI) 0.26 to 0.94], p = 0.030). These benefits were associated with similarly favorable effects on cardiac remodeling, such as improved left ventricular ejection fraction in the PCI group (+4.4% change [95% CI 1.1 to 7.6], p = 0.009).

CONCLUSIONS

Percutaneous coronary intervention of the IRA performed late (12 h to 60 days) after AMI is associated with significant improvements in cardiac function and survival.

Late Intervention on an Occluded Infarct-Related Artery: A Meta-analysis of the Randomized Controlled Trials

Context

Late intervention to open an occluded infarct-related artery (IRA) after initial acute myocardial infarction was postulated to lead to clinical benefit.

Objective

To conduct a meta-analysis of the randomized trials.

Study Selection

Eligibility criteria were: 1) randomized trials comparing percutaneous coronary intervention (PCI) in a totally occluded artery (TIMI flow 0-1) versus medical therapy, 2) in stable post myocardial infarction (MI) patients without spontaneous or low level exercise induced ischemia, 3) trials with a time from the onset of symptoms to randomization >24 hours, but <6 weeks, and 4) trials reporting mortality and recurrent MI as an endpoint. Of 961 citations reviewed, 3 disagreements were easily resolved by discussion and 6 trials were selected for inclusion.

Data Synthesis

The primary endpoint was the composite of recurrent MI or death. The secondary endpoints were the development of heart failure or recurrent myocardial infarction. In a meta-analysis of the 6 trials, which included 2642 patients, late intervention of an IRA had a RR of death or recurrent MI of 1.12 (95% CI 0.91-1.38). Data regarding the development of heart failure was available for 4 trials. In a meta-analysis of these 4 trials, which included 2527 patients, late intervention of an IRA had a RR of 0.79 (95% CI 0.58-1.08). Data regarding the occurrence of recurrent MI was available for 5 trials. In a meta-analysis of these 5 trials, which included 2598 patients, late intervention of an IRA had a RR of 1.28 (95% CI 0.91-1.79).

Conclusions

Our meta-analysis of the currently available randomized data addressing late intervention of an occluded IRA failed to reveal clinical benefit with regard to the clinical endpoints of death, heart failure or reinfarction. The trend towards an increase in reinfarction among the PCI treated patients suggested by the Open Artery Trial (OAT) investigators persisted, but did not achieve statistical significance.

Multidetector row computed tomography can identify and characterize the occlusive culprit lesions in patients early (within 24 hours) after acute myocardial infarction

BACKGROUND

The reliable noninvasive assessment of occluded disrupted plaques and thromboses in culprit vessels could constitute an important step forward in risk stratification of patients early after acute myocardial infarction (AMI). However, noninvasive identification of patency of culprit vessels remains a challenging issue. This prospective study was designed to identify the occluded culprit vessels by multidetector row computed tomography (MDCT) and to compare the stenotic and occlusive culprit lesions by MDCT in patients early (within 24 hours) after AMI.

METHODS

We enrolled 62 patients with first Q-wave AMI (54 males). Multidetector row computed tomography was performed 16.5 +/- 7.1 hours after the onset of chest pain without any complication. Coronary angiography was done within 6 hours after MDCT. Patients were divided into 2 groups according to angiographic findings: stenotic group (35 patients) and occluded group (27 patients). The following MDCT data were collected: luminal artery stenosis, remodeling index, plaque burden, and lesion attenuation.

RESULTS

Compared to coronary angiography, MDCT detected occluded culprit vessels with sensitivity, specificity, negative predict value, and positive predict value of 92.6%, 88.6%, 93.9%, and 86.2%, respectively. Compared with the stenotic group, culprit lesions in the occlusive group had significantly longer length (18.9 +/- 9.7 vs 11.9 +/- 6.2 mm; P = .024) and higher MDCT lesion attenuation (38.8 +/- 15.6 vs 29.2 +/- 12.9 Hounsfield unit; P = .008). Multidetector row computed tomography attenuation was negatively correlated with thrombolysis in myocardial infarction flow (Spearman rho = -0.46; P < .001).

CONCLUSIONS

Multidetector row computed tomography could accurately and safely identify occluded culprit lesions in patients early after AMI, providing important information to aid in risk stratification.

Surgery for myocardial salvage in acute myocardial infarction and acute coronary syndromes

This article addresses the pathophysiology, the treatment options, and their rationale in the setting of life-threatening acute myocardial infarction and acute on chronic ischemia. Although biases may exist between cardiologists and surgeons, with this review, we hope to provide the reader with information that will shed light on the options that best suit the individual patient in a given set of circumstances.