Preinfarction angina as a major predictor of left ventricular function and long-term prognosis after a first Q wave myocardial infarction

Relationship between in-hospital mortality and creatinine/albumin in patients with ST-elevation myocardial infarction without standard modifiable risk factors

Background: Diabetes, hypertension, hyperlipidemia and smoking are associated with coronary artery disease and ST-elevation myocardial infarction (STEMI). However, patients without any classic risk factors have a higher mortality rate in the post-STEMI period. The aim of this study was to investigate the relationship between in-hospital mortality and creatinine/albumin ratio in patients with STEMI without modifiable risk factors. Materials & methods: All patients included in this study with a diagnosis of STEMI and who underwent primary percutaneous intervention between 2016 and 2020 were retrospectively analyzed. Patients were included in the standard modifiable cardiovascular risk factor (SMuRF) group if at least diabetes, hypertension, smoking or hyperlipidemia was present according to risk factors. Patients without these risk factors were considered the non-SMuRF group. Results: Creatinine/albumin ratio was found to be higher in non-SMuRF patients with mortality (p < 0.001). In multivariate logistic regression analysis, ejection fraction, hemoglobin and SMuRF were found to be inversely associated with in-hospital mortality (odds ratio [OR]: 0.48, 95% CI: 0.35-0.66, p < 0.001; OR: 0.70, 95% CI: 0.56-0.88, p = 0.002; OR: 0.57, 95% CI: 0.34-0.95, p = 0.03, respectively). Conclusion: The creatinine/albumin ratio can be used as a predictor of mortality in these patients; it can help identify high-risk patients beforehand.

Prior angina reduces ıschemic mitral regurgitation in patients with ST-Elevation myocardial ınfarction, role of ıschemic preconditioning

Mitral regurgitation may develop due to left ventricular (LV) remodeling within 3 months following acute myocardial infarction (AMI) and is called ischemic mitral regurgitation (IMR). Ischemic preconditioning (IPC) has been reported as the most important mechanism of the association between prior angina and the favorable outcome. The aim of this study was to investigate the effect of prior angina on the development and severity of IMR at 3rd month in patients with ST elevation MI (STEMI). Fourty five (45) patients admitted with STEMI and at least mild IMR, revascularized by PCI were enrolled. According to presence of prior angina within 72 h before STEMI, patients were then divided into two groups as angina (+) (n:26; 58%) and angina (-) (n:19; 42%). All patients underwent 2D transthoracic echocardiography at 1st, 3rd days and 3rd month. IMR was evaluated by proximal isovelocity surface area (PISA) method: PISA radius (PISA-r), effective regurgitant orifice area (EROA), regurgitant volume (Rvol). LV ejection fraction (EF %) was calculated by Simpson's method. High sensitive troponin T (hs-TnT), creatine phosphokinase myocardial band (CK-MB) and N-terminal pro-brain natriuretic peptid (NTpro-BNP) levels were compared between two groups. Although PISA-r, EROA and Rvol were similar in both groups at 1st and 3rd days, all were significantly decreased (p = 0.012, p = 0.007, p = 0.011, respectively) and EF was significantly increased (p< 0 .001) in angina (+) group at 3rd month. NTpro-BNP and hs-TnT levels at 1st day and 3rd month were similar, however CK-MB level at 3rd month was found to be significantly lower in the angina (+) group (p = 0.034). At the end of the 3rd month, it was observed that the severity of IMR evaluated by PISA method was decreased and EF increased significantly in patients who defined angina within 72 h prior to STEMI, suggesting a relation with IPC.

Pre-infarction angina is associated with improved prognosis in diabetic patients with ST-elevation myocardial infarction - data from a contemporary cohort

BACKGROUND

Pre-infarction angina (PIA) is associated with improved prognosis in patients with ST-elevation myocardial infarction (STEMI). Some studies suggest that diabetes may blunt the effect of ischaemic preconditioning. We sought to study the impact of PIA in diabetic patients with STEMI.

METHODS

Consecutive patients with STEMI who underwent primary angioplasty were included. PIA was defined as ≥1 episode of chest pain during the week preceding STEMI diagnosis. Incident major adverse cardiovascular events (MACE) were defined as the first occurrence of all-cause death, stroke or acute myocardial infarction.

RESULTS

Of the 1143 included patients, 25% were diabetic and 32% had a history of PIA. Diabetic patients with PIA had smaller infarct sizes as estimated by peak creatine kinase (CK) [1144 (500-2212) vs. 1715 (908-3309) U/L, P = 0.003] and peak troponin [3.30 (1.90-6.58) vs. 4.88 (2.50-9.58) ng/ml, P = 0.002], compared to diabetics without PIA. They also had a lower likelihood of evolving with moderate to severe reduced left ventricle ejection fraction (LVEF) (25.6%, n = 22 vs. 46.6%, n = 82, P = 0.001). In non-diabetic patients, PIA was associated with reduced peak CK [1549 (909-2909) vs. 1793 (996-3078), P = 0.0497], but not troponin (3.74 [2.23-7.11] vs. 4.56 [2.44-7.77] ng/ml, P = 0.19), and was not associated with reduced LVEF (32.0%, n = 85 vs. 37.4%, n = 207, P = 0.13). Both diabetic and non-diabetic patients with PIA had a lower likelihood of evolving with a Killip class III/VI (non-diabetic patients: 5.6% vs. 14.1%, P = 0.002; diabetic patients: 12.8% vs. 24.6%, P = 0.049). Over a median follow-up of 18.0 (12.1-25.5) months, PIA was associated with a significant reduction in the incidence of MACE [hazard ratio 0.52, 95% confidence interval (CI) 0.37-0.74, P < 0.001], irrespective of diabetes status.

CONCLUSION

PIA is an independent predictor of favourable outcomes in the setting of STEMI for both diabetic and non-diabetic patients.

Impact of Previous Angina on Clinical Outcomes in ST-Elevation Myocardial Infarction Underwent Percutaneous Coronary Intervention

The present study sought to assess the impact of previous angina symptoms on real world clinical outcomes in patients with ST-elevation myocardial infarction (STEMI) who had undergone successful percutaneous coronary interventions using drug-eluting stents (DES). Patients were selected from 13,650 consecutive patients enrolled in the Korea Acute Myocardial Infarction-National Institute of Health (KAMIR-NIH) registry. A total of 5167 STEMI patients were divided into a previous-angina group (n=1129) and a control group (n=4038). Major adverse cardiac and cerebrovascular events (MACCEs) that included all-cause death, recurrent myocardial infarction (re-MI), repeat PCI, coronary artery bypass graft (CABG), cerebrovascular accident (CVA). Among the 5167 patients with STEMI, MACCEs had occurred in 168 patients in the previous-angina group (14.9%) and 726 patients in the control group (18.0%) (HR, 0.76, 95% CI, 0.60-0.96, p=0.019) at the two-year (800-day) for clinical outcomes. Previous angina was associated with better clinical outcomes with respect to all-cause death (HR, 0.65, 95% CI, 0.44-0.96, p=0.029) and cardiac death (HR, 0.52, 95% CI, 0.31-0.84, p=0.008). Previous angina was a negative risk factor for adverse cardiac events. A previous history of angina predisposes a patient to a favorable outcome after acute myocardial infarction (AMI) in patients with DES implantation.

Direct implantations of erythropoietin and autologous EPCs in critical limb ischemia (CLI) area restored CLI area blood flow and rescued remote AMI-induced LV dysfunction

BACKGROUND

This study tested the hypothesis that intramuscular injections of erythropoietin (EPO) and endothelial progenitor cells (EPC) to critical limb ischemia (CLI; primary treatment site) could also improve heart function in rat after acute myocardial infarction (AMI; remote ischemic organ).

METHOD

Adult-male SD rats (n = 40) were equally categorized into group 1 (sham-operated control), group 2 (CLI-AMI), group 3 [CLI-AMI + EPO (10 mg/kg)], group 4 [CLI-AMI + EPCs (1.2 × 10⁶)] and group 5 (CLI-AMI + EPCs + EPO).

RESULTS

By day 21 (end of study period), 2-D echo and Laser doppler showed that left-ventricular injection fraction (LVEF) and the ratio of ischemic to normal blood flow were highest in group 1, lowest in group 2, significantly higher in group 5 than in groups 3 and 4, but not different in the latter two groups (all p < 0.0001). Flow cytometry and ELISA demonstrated that circulating angiogenesis factors were significantly progressively increased from groups 1 to 5 (all p < 0.001). The number of small vessels and protein (CD31/eNOS)/cellular (vWF) expressions reflecting integrity of endothelium exhibited an identical pattern to LVEF whereas protein (VEGF/SDF-1α)/cellular (VEGF) expressions were significantly progressively increased from groups 1 to 5 in quadriceps and heart tissues (all p < 0.0001). Protein expressions of apoptotic (Bax/caspase-3/PARP)/inflammatory (MMP-9) and microscopic findings of ischemic/fibrotic/collagen-deposition areas and DNA-damage marker (γ-H2AX+) were lowest in group 1 and significantly progressively decreased from groups 2 to 5 in quadriceps and heart tissues (all p < 0.0001).

CONCLUSIONS

Direct injection of EPO-EPC into CLI effectively restored blood flow in the CLI area and also preserved remote heart function.

Relation of coronary culprit lesion morphology determined by optical coherence tomography and cardiac outcomes to preinfarction angina in patients with acute myocardial infarction

BACKGROUND

While preinfarction angina pectoris (pre-IA) is recognized as favorable effects on acute myocardial infarction (AMI), the detail has not been fully investigated. The aims of the current study were to clarify patient characteristics, lesion morphologies determined by optical coherence tomography (OCT), and cardiac outcomes related to pre-IA in patients with AMI.

METHODS

Clinical data and outcomes were compared between AMI patients with pre-IA (pre-IA group, n = 507) and without pre-IA (non-pre-IA group, n = 653). Angiography and OCT findings were analyzed in patients with pre-intervention OCT and compared between groups of pre-IA (n = 219) and non-pre-IA (n = 269).

RESULTS

ST-segment elevation myocardial infarction (61% vs. 75%, p < 0.001) and cardiogenic shock (8% vs. 14%, p = 0.001) were less prevalent in pre-IA group. Peak creatine kinase-MB levels were lower in pre-IA group (median 83 IU/mL vs. 126 IU/mL, p < 0.001). In pre-intervention coronary angiography findings, initial TIMI flow grade 0/1 (43% vs. 56%, p = 0.019) and Rentrop collateral circulation 0/1 (69% vs. 79%, p = 0.018) were less frequently observed in pre-IA than in non-pre-IA patients. In post-thrombectomy OCT images, plaque rupture (39% vs. 56%, p = 0.003) and red thrombi (42% vs. 54%, p = 0.027) were also less frequently observed in pre-IA group. Kaplan-Meier estimate survival curves showed that cardiac death at 12-months was lower in pre-IA group than in non-pre-IA group (6.9% vs. 10.1%, p = 0.036).

CONCLUSIONS

Patients with pre-IA had less severe AMI on admission, smaller infarction size, and more favorable long-term survival, which may be caused by difference of lesion morphology between patients with and without pre-IA.

Inflammatory Mechanisms of Cardiovascular Remodeling

Inflammation and fibrosis play an important role in the development and progression of cardiovascular diseases. Acute coronary syndrome (ACS) is caused by rupture of inflamed atherosclerotic plaque and subsequent atherothrombosis. Recent studies have shown that inflammatory markers such as C-reactive protein (CRP) can predict ACS development and have demonstrated the effectiveness of new therapeutic approaches targeting inflammation. Studies have also shown that an enhanced inflammatory response after myocardial infarction (MI) is associated with cardiac rupture, ventricular aneurysm formation, and exacerbation of left ventricular (LV) remodeling. Inflammation is a physiological reaction in which fibrosis is induced to facilitate the healing of tissue damage. However, when an excessive inflammatory response consisting mainly of monocytes/macrophages is induced by various factors, impaired reparative fibrosis and resulting pathological remodeling processes may occur. A similar phenomenon is observed in abdominal aortic aneurysm (AAA) expansion. In contrast, myocardial diseases such as inflammatory dilated cardiomyopathy (DCMI) and valvular diseases such as aortic valve stenosis (AS) are characterized by chronic inflammation mediated mainly by T lymphocytes and the associated enhancement of reactive fibrosis. Thus, inflammation can take 2 paths (the inhibition or promotion of fibrosis), depending on the phase of inflammation, inducing pathological cardiovascular remodeling. Elucidation of the regulatory mechanisms of inflammation and fibrosis will contribute to the development of new therapeutic approaches for cardiovascular diseases.

Association Between Preinfarction Angina and Angiographic Findings in Non-ST-Segment Elevation Myocardial Infarction

BACKGROUND

The association between preinfarction angina and angiographic findings has not been elucidated in patients with non-ST-segment elevation myocardial infarction (NSTEMI).

HYPOTHESIS

Patients with preinfarction angina have favorable angiographic findings.

METHODS

This retrospective study analyzed 481 patients who underwent coronary angiography within 5 days of presenting NSTEMI. Preinfarction angina was defined as experiencing ≥1 chest-pain episode within 7 days prior to admission. Infarct size was measured as the peak cardiac troponin I (cTnI) level, and large myocardial infarction (MI) was defined as a peak cTnI level >85th percentile value in the study population. Infarct-related artery (IRA) patency was defined as Thrombolysis In Myocardial Infarction grade 2 or 3 flow. Clinical and angiographic characteristics and in-hospital mortality were compared between patients with and without preinfarction angina.

RESULTS

Among 481 patients, 200 (42%) had preinfarction angina. Preinfarction angina was associated with smaller infarct size, indicated by lower peak cTnI levels (P = 0.006) and lower incidence of large MI (P = 0.02), and IRA patency (P = 0.03). There was no significant difference in in-hospital mortality. On multivariate analysis, both preinfarction angina (odds ratio: 0.53, 95% confidence interval: 0.29-0.94, P = 0.03) and IRA patency (odds ratio: 0.30, 95% confidence interval: 0.17-0.52, P < 0.001) were independent negative predictors of large MI.

CONCLUSION

Our study demonstrates that preinfarction angina is a predictor of smaller infarct size and infarct-related artery patency in NSTEMI patients, suggesting that NSTEMI patients presenting without preinfarction angina are at increased risk of developing a large MI.

Time-dependent effect of preinfarction angina pectoris and intermittent claudication on mortality following myocardial infarction: A Danish nationwide cohort study

BACKGROUND

As proxies for local and remote ischemic preconditioning, we examined whether preinfarction angina pectoris and intermittent claudication influenced mortality following myocardial infarction.

METHODS

Using medical registries, we conducted a nationwide population-based cohort study of all first-time myocardial infarction patients in Denmark during 2004-2012 (n=70,458). We computed all-cause and coronary mortality rate ratios (MRRs). We categorized time between angina/claudication presentation and subsequent myocardial infarction as 0-14, 15-30, 31-90, and > 90 days. We adjusted for age, sex, coronary intervention, comorbidities, and medication use.

RESULTS

Among all myocardial infarction patients, 18.4% had prior angina and 3.8% had prior intermittent claudication. Compared to patients without prior angina, the adjusted 30-day coronary MRR was 0.85 (95% confidence interval (CI): 0.80-0.92) for stable and 0.68 (95% CI: 0.58-0.79) for unstable angina patients. The mortality reduction increased when angina presented close to myocardial infarction and was higher for unstable than for stable angina. Thus, the 30-day coronary MRR was 0.72 (95% CI: 0.51-1.02) for stable angina and 0.35 (95% CI: 0.17-0.73) for unstable angina presenting within 14 days before MI. The results were robust for all-cause mortality and in numerous subgroups, including women, diabetics, patients treated with PCI, and patients treated with and without cardioprotective drugs. Preinfarction intermittent claudication was associated with higher short- and long-term mortality compared to patients without intermittent claudication.

CONCLUSIONS

Preinfarction angina reduced 30-day mortality, particularly when unstable angina closely preceded MI. Preinfarction intermittent claudication was associated with increased short- and long-term mortality.

Effect of preinfarction angina pectoris on long-term survival in patients with ST-segment elevation myocardial infarction who underwent primary percutaneous coronary intervention

The influence of preinfarction angina pectoris (AP) on long-term clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI) who underwent primary percutaneous coronary intervention (PCI) remains controversial. In 5,429 patients with acute myocardial infarction (AMI) enrolled in the Coronary Revascularization Demonstrating Outcome Study in Kyoto AMI Registry, the present study population consisted of 3,476 patients with STEMI who underwent primary PCI within 24 hours of symptom onset and in whom the data on preinfarction AP were available. Preinfarction AP defined as AP occurring within 48 hours of hospital arrival was present in 675 patients (19.4%). Patients with preinfarction AP was younger and more often had anterior AMI and longer total ischemic time, whereas they less often had history of heart failure, atrial fibrillation, and shock presentation. The infarct size estimated by peak creatinine phosphokinase was significantly smaller in patients with than in patients without preinfarction AP (median [interquartile range] 2,141 [965 to 3,867] IU/L vs 2,462 [1,257 to 4,495] IU/L, p <0.001). The cumulative 5-year incidence of death was significantly lower in patients with preinfarction AP (12.4% vs 20.7%, p <0.001) with median follow-up interval of 1,845 days. After adjusting for confounders, preinfarction AP was independently associated with a lower risk for death (hazard ratio 0.69, 95% confidence interval 0.54 to 0.86, p = 0.001). The lower risk for 5-year mortality in patients with preinfarction AP was consistently observed across subgroups stratified by total ischemic time, initial Thrombolysis In Myocardial Infarction flow grade, hemodynamic status, infarct location, and diabetes mellitus. In conclusion, preinfarction AP was independently associated with lower 5-year mortality in patients with STEMI who underwent primary PCI.

Association between clinical presentations before myocardial infarction and coronary mortality: a prospective population-based study using linked electronic records

Background

Ischaemia in different arterial territories before acute myocardial infarction (AMI) may influence post-AMI outcomes. No studies have evaluated prospectively collected information on ischaemia and its effect on short- and long-term coronary mortality. The objective of this study was to compare patients with and without prospectively measured ischaemic presentations before AMI in terms of infarct characteristics and coronary mortality.

Methods and results

As part of the CALIBER programme, we linked data from primary care, hospital admissions, the national acute coronary syndrome registry and cause-specific mortality to identify patients with first AMI (n = 16,439). We analysed time from AMI to coronary mortality (n = 5283 deaths) using Cox regression (median 2.6 years follow-up), comparing patients with and without recent ischaemic presentations. Patients with ischaemic presentations in the 90 days before AMI experienced lower coronary mortality in the first 7 days after AMI compared with those with no prior ischaemic presentations, after adjusting for age, sex, smoking, diabetes, blood pressure and cardiovascular medications [HR: 0.64 (95% CI: 0.57–0.73) P < 0.001], but subsequent mortality was higher [HR: 1.42 (1.13–1.77) P = 0.001]. Patients with ischaemic presentations closer in time to AMI had the lowest seven day mortality (P-trend = 0.001).

Conclusion

In the first large prospective study of ischaemic presentations prior to AMI, we have shown that those occurring closest to AMI are associated with lower short-term coronary mortality following AMI, which could represent a natural ischaemic preconditioning effect, observed in a clinical setting.

Clinical trials registration

Clinicaltrials.gov identifier NCT01604486.

Preinfarction angina reduces infarct size in ST-elevation myocardial infarction treated with percutaneous coronary intervention

BACKGROUND

Preinfarction angina may act as a clinical surrogate of ischemic preconditioning that may reduce infarct size and improve mortality in the setting of thrombolytic therapy for ST-elevation myocardial infarction. However, the benefits of preinfarction angina in the setting of primary percutaneous coronary intervention with stenting is inconclusive because of the greater achievement of infarct artery patency and speed of reperfusion.

METHODS AND RESULTS

To identify a homogeneous population, we performed a retrospective analysis of 1031 patients admitted with a first ST-elevation myocardial infarction with ischemic times between 1 and 6 hours who received primary percutaneous coronary intervention. We identified 245 patients who had occluded arteries on presentation, of which 79 patients had documented preinfarction angina defined as chest pain within 24 hours of infarction. Infarct size was measured as the peak creatine kinase level, a metric supported in a subgroup by late enhancement on cardiac magnetic resonance imaging. Patients with preinfarction angina (n=79) had a 50% reduction in infarct size compared with those patients without preinfarction angina (n=166) by both peak creatine kinase (1094±75 IU/L versus 2270±102 IU/L; P<0.0001) and creatine kinase area under curve (18 420±18 941 versus 36 810±21 741 IU/h per liter; P<0.0001) despite having identical ischemic times (185±8 minutes versus 181±5 minutes; P=0.67) and angiographic area at risk (24.1±1.2% versus 25.3±0.9%; P=0.43). There was an absolute 4% improvement in left ventricular ejection fraction before discharge in those patients with preinfarction angina (P<0.02).

CONCLUSIONS

The occurrence of preinfarction angina is associated with significant myocardial protection in the setting of primary percutaneous coronary intervention with stenting during ST-elevation myocardial infarction. Because preinfarction angina is relatively common, it is important that these patients be identified in clinical trials investigating therapies designed to reduce reperfusion injury and infarct size.

Effects of diabetes on myocardial infarct size and cardioprotection by preconditioning and postconditioning

In spite of the current optimal therapy, the mortality of patients with ischemic heart disease (IHD) remains high, particularly in cases with diabetes mellitus (DM) as a co-morbidity. Myocardial infarct size is a major determinant of prognosis in IHD patients, and development of a novel strategy to limit infarction is of great clinical importance. Ischemic preconditioning (PC), postconditioning (PostC) and their mimetic agents have been shown to reduce infarct size in experiments using healthy animals. However, a variety of pharmacological agents have failed to demonstrate infarct size limitation in clinical trials. One of the possible reasons for the discrepancy between the results of animal experiments and clinical trials is that co-morbidities, including DM, modified myocardial responses to ischemia/reperfusion and to cardioprotective agents. Here we summarize observations of the effects of DM on myocardial infarct size and ischemic PC and PostC and discuss perspectives for protection of DM hearts.

The role of myocardial ischaemic preconditioning during beating heart surgery: biological aspect and clinical outcome

Short periods of ischaemia consecutive to reperfusion periods before a sustained ischaemic condition, the so-called ischaemic preconditioning (IP), aim to protect myocardial cells against prolonged ischaemia. IP appears as a considerable endogenous cardioprotective mechanism decreasing the infarct size after total occlusion in either experimental models or humans. Angina periods before an acute coronary syndrome limit the myocardial infarction being protective for the myocardium. Our report aims to review the international bibliography of the IP during off-pump coronary artery bypass grafting.

Beneficial effect of ischemic preconditioning on post-infarction left ventricular remodeling and global left ventricular function

BACKGROUND

Preinfarction angina (PA) is a clinical analogue of ischemic preconditioning that improves postinfarct prognosis. Data concerning the association of PA with post infarction left ventricular (LV) remodeling and LV diastolic function are limited. We aimed to evaluate this association in patients with acute myocardial infarction (AMI) in the modern clinical era of widespread use of revascularization and antiremodeling medical treatment.

METHODS

We studied 53 patients with anterior AMI who underwent complete reperfusion and received up to date antiremodeling medical treatment. LV remodeling, systolic and diastolic function were assessed using 2D echocardiography at baseline and 6 at months follow-up. Patients were divided into two groups regarding the presence or absence of PA.

RESULTS

LV remodeling at follow-up was less frequent in the PA group (25 vs. 55 %, P<.05). Patients with PA had lower end-systolic volume index at baseline and follow up (24.1±6 vs. 30.1±14 ml/m(2), P<.001 and 25.3±8 vs. 35.6±2 ml/m(2), P=.001 respectively). Additionally at 6 months, they had better LV ejection fraction (52.1±9 vs. 42.9±10 %, P=.002) and exhibited improved diastolic filling as reflected by mitral E/e' (14.6±5 vs. 18.8±8, P=.05).

CONCLUSIONS

Ischemic preconditioning in the form of PA promotes better LV systolic and diastolic function in the mid-term and is associated with less postinfarct LV remodeling in this specific study population. The results of the study underline the possible need for further risk stratification of AMI patients regarding the absence of PA.

Myocardium-derived conditioned medium improves left ventricular function in rodent acute myocardial infarction

BACKGROUND

We investigated whether myocardium-derived conditioned medium (MDCM) is effective in preserving left ventricular (LV) function in a rat acute myocardial infarction (AMI) model.

METHODS

Adult male Sprague-Dawley (SD) rats (n = 36) randomized to receive either left coronary artery ligation (AMI induction) or thoracotomy only (sham procedure) were grouped as follows (n = 6 per group): Group I, II, and III were sham-controls treated by fresh medium, normal rat MDCM, and infarct-related MDCM, respectively. Group IV, V, and VI were AMI rats treated by fresh medium, normal MDCM, and infarct-related MDCM, respectively. Either 75 μL MDCM or fresh medium was administered into infarct myocardium, followed by intravenous injection (3 mL) at postoperative 1, 12, and 24 h.

RESULTS

In vitro studies showed higher phosphorylated MMP-2 and MMP-9, but lower α-smooth muscle actin and collagen expressions in neonatal cardiac fibroblasts treated with MDCM compared with those in the cardiac fibroblasts treated with fresh medium (all p < 0.05). Sirius-red staining showed larger collagen deposition area in LV myocardium in Group IV than in other groups (all p < 0.05). Stromal cell-derived factor-1α and CXCR4 protein expressions were higher in Group VI than in other groups (all p < 0.05). The number of von Willebrand factor- and BrdU-positive cells and small vessels in LV myocardium as well as 90-day LV ejection fraction were higher, whereas oxidative stress was lower in Group VI than in Group IV and Group V (all p < 0.05).

CONCLUSION

MDCM therapy reduced cardiac fibrosis and oxidative stress, enhanced angiogenesis, and preserved 90-day LV function in a rat AMI model.

Impact of initial degree of coronary narrowing on left ventricular function in first myocardial infarction

To determine whether the initial degree of coronary narrowing prior to a first myocardial infarction (MI) affects left ventricular function, we analyzed paired coronary angiograms and left ventriculography in 41 consecutive MI patients in whom coronary angiography was obtained before and after MI. Patients were divided into 2 groups according to coronary narrowing of the infarct culprit lesion at first angiogram; a significant narrowing group (group S, 15 patients) and a nonsignificant narrowing group (group N, 26 patients). Significant narrowing was defined as more than 75% stenosis of an infarct-related segment in the first angiography and nonsignificant narrowing was less than 50% narrowing. Clinical characteristics were similar in the two groups, with the exception of initial diameter stenosis. LV function was normal in both groups at initial examination. Group S patients had a higher prevalence of angina prior to MI (73% versus 23%; P = 0.001), good collateral development (73% versus 35%; P = 0.02), and non-Q MI (73% versus 27%; P = 0.004) than group N patients. RWM was also superior in group S compared with group N. The deterioration of global and infarction zone function was mild in group S compared with group N (group S; median EF -10%, RWM -0.27 SD/chord, group N; median EF -26%, RWM -1.62 SD/chord, P = 0.001). We conclude that deterioration of LV wall motion in patients with severe stenosis in their initial stenosis would be milder than in AMI that developed from a mild degree of stenosis.

Role of ischemic preconditioning and inflammatory response in the development of malignant ventricular arrhythmias after reperfused ST-elevation myocardial infarction

BACKGROUND

Sustained ventricular tachycardia and ventricular fibrillation (VT/VF) are major complications of ST-elevation myocardial infarction (STEMI), even in the era of reperfusion therapy. We sought to clarify the determinants of VT/VF after reperfused STEMI.

METHODS AND RESULTS

Consecutive STEMI patients treated with primary percutaneous coronary intervention (n=457) were divided into 2 groups by the presence or absence of VT/VF during hospitalization. Serum C-reactive protein (CRP) level and peripheral white blood cell (WBC) count were serially measured. VT/VF was observed in 54 patients (12%). Prior infarction was more common and preinfarction angina was less in patients with VT/VF than those without. Peak CRP level (P < .0001), WBC count on admission (P=.008), and maximum WBC count (P=.0014) were higher in patients with VT/VF than those without. VT/VF, especially VT/VF later than 48 hours after onset, was associated with greater left ventricular (LV) dimension during convalescence. Kaplan-Meier curves and log-rank test revealed VT/VF to be a significant determinant of long-term major adverse cardiac events. Multivariate analysis revealed that prior infarction, absence of preinfarction angina, and peak CRP >or=10mg/dL were independent determinants of VT/VF.

CONCLUSIONS

Lack of ischemic preconditioning, enhanced inflammatory response, and subsequent LV dysfunction are related to the development of VT/VF after STEMI.

Time courses of subcellular signal transduction and cellular apoptosis in remote viable myocardium of rat left ventricles following acute myocardial infarction: role of pharmacomodulation

We tested hypothesis that acute myocardial infarction (AMI) induces cellular apoptosis and serial changes of protein kinase C epsilon (PKC-epsilon) and p38 mitogen-activated protein kinase (p38 MAPK), and tested cardio-protective effect of losartan in this condition. The rats were assigned to group A (sacrificed on day 2), group B (sacrificed on day 5), and group C (sacrificed on day 14). Rats in each group were further randomized into the following groups: AMI (ligation of left coronary artery) without losartan (AMI-L0); AMI with losartan 20 mg/ kg/d (AMI-L1); and sham groups (L0 and L1). The PKC-epsilon expression in membrane compartment was increased in AMI-L1 group than in other groups on day 5 and in AMI groups than in sham groups on day 14 (P < .01). Phosphorylated form of cytosolic p38 MAPK level was increased in AMI-L1 than in other groups on day 14 (P < .05). Furthermore, 14-day left ventricular ejection fraction was higher and cellular apoptosis was lower in AMI-L1 group than in AMI-L0 group (P < .0001).

Preinfarction angina prevents left ventricular remodeling in patients treated with thrombolysis for myocardial infarction

BACKGROUND

It has been shown that preinfarction angina may have beneficial effects on infarct size and mortality. However, there are no studies that have serially assessed the impact of preinfarction angina on left ventricular (LV) function in a large series of patients.

HYPOTHESIS

The study was undertaken to determine whether preinfarction angina (within 7 days before infarction) influences LV remodeling.

METHODS

In all, 119 consecutive patients with acute myocardial infarction were serially evaluated by 2-dimensional echocardiography (on Days 1, 2, 3, and 7; at 3 and 6 weeks; and at 3, 6, and 12 months following infarction). Left ventricular volumes were determined using Simpson's biplane formula and normalized for body surface area. Wall motion score index and sphericity index were calculated for each study. Coronary angiography was performed before discharge.

RESULTS

Preinfarction angina was detected in 39 of 119 patients. Initial echocardiographic and clinical data as well as the incidence of patent infarct-related artery and collaterals were similar for patients with and without preinfarction angina. In the subset of thrombolysed patients, patients with preinfarction angina showed decrease of LV end-diastolic and end-systolic volumes during the follow-up period (p = 0.033 and p = 0.001, respectively), and improvement of wall motion score index (p < 0.001) and ejection fraction occurred (p = 0.001), without changing of LV shape (p > 0.05); in addition, patients with preinfarction angina had smaller LV volumes and higher ejection fraction than did those without angina, from 3 weeks onward. These favorable effects were not detected in patients not treated with thrombolysis.

CONCLUSIONS

These data indicate that preinfarction angina has an inhibiting effect on long-term LV remodeling in patients who underwent thrombolysis for first acute myocardial infarction. It appears that preinfarction angina has no impact on infarct size and early postinfarction LV function.

Delayed inhibition of agonist-induced granulocyte-platelet aggregation after low-dose sevoflurane inhalation in humans

BACKGROUND

Sevoflurane can be used as sedative-analgesic drug with endothelial protective properties. We tested whether low-dose sevoflurane inhalation provides sustained inhibition of detrimental granulocyte-platelet aggregation in humans.

METHODS

Ten healthy male volunteers were enrolled in this crossover study. Each subject inhaled sevoflurane for 1 h at 0.5-1 vol % end-tidal concentration in oxygen (50 vol %). Inhaling oxygen (50 vol %) alone served as control. Venous blood samples were collected at baseline before inhalation, immediately after inhalation, and 24 h thereafter, and were used for flow cytometry to determine platelet surface marker (CD41, CD42b, CD62P/P-selectin, and PAC-1) on platelets and granulocytes and for kaolin-induced clot formation, as assessed by thromboelastography. In flow cytometry experiments, platelets were stimulated with arachidonic acid (AA, 30 microM), adenosine diphosphate (ADP, 1 microM), and thrombin receptor agonist peptide-6 (TRAP-6, 6 microM).

RESULTS

AA, ADP, and TRAP-6 markedly increased the expression of CD62P on platelets, whereas CD42b (shedding) and PAC-1 (heterotypic conjugates) expression decreased. The amount of granulocyte-platelet aggregates increased upon agonist stimulation. Low-dose sevoflurane inhalation reduced ADP-induced CD62P expression on platelets 24 h after inhalation, and inhibited the formation of granulocyte-platelet aggregates under stimulation with AA and ADP after 1 and 24 h, and with TRAP-6 after 24 h compared with control. Inhibition of granulocyte-platelet aggregates was accompanied by reduced clot firmness 24 h after sevoflurane inhalation compared with control.

CONCLUSIONS

We demonstrated for the first time that inhaling low-dose sevoflurane (<1 vol % end-tidal) inhibits agonist-induced granulocyte-platelet interactions 24 h after administration and thus counteracts thromboinflammatory processes.

Interaction of cardiovascular risk factors with myocardial ischemia/reperfusion injury, preconditioning, and postconditioning

Therapeutic strategies to protect the ischemic myocardium have been studied extensively. Reperfusion is the definitive treatment for acute coronary syndromes, especially acute myocardial infarction; however, reperfusion has the potential to exacerbate lethal tissue injury, a process termed "reperfusion injury." Ischemia/reperfusion injury may lead to myocardial infarction, cardiac arrhythmias, and contractile dysfunction. Ischemic preconditioning of myocardium is a well described adaptive response in which brief exposure to ischemia/reperfusion before sustained ischemia markedly enhances the ability of the heart to withstand a subsequent ischemic insult. Additionally, the application of brief repetitive episodes of ischemia/reperfusion at the immediate onset of reperfusion, which has been termed "postconditioning," reduces the extent of reperfusion injury. Ischemic pre- and postconditioning share some but not all parts of the proposed signal transduction cascade, including the activation of survival protein kinase pathways. Most experimental studies on cardioprotection have been undertaken in animal models, in which ischemia/reperfusion is imposed in the absence of other disease processes. However, ischemic heart disease in humans is a complex disorder caused by or associated with known cardiovascular risk factors including hypertension, hyperlipidemia, diabetes, insulin resistance, atherosclerosis, and heart failure; additionally, aging is an important modifying condition. In these diseases and aging, the pathological processes are associated with fundamental molecular alterations that can potentially affect the development of ischemia/reperfusion injury per se and responses to cardioprotective interventions. Among many other possible mechanisms, for example, in hyperlipidemia and diabetes, the pathological increase in reactive oxygen and nitrogen species and the use of the ATP-sensitive potassium channel inhibitor insulin secretagogue antidiabetic drugs and, in aging, the reduced expression of connexin-43 and signal transducer and activator of transcription 3 may disrupt major cytoprotective signaling pathways thereby significantly interfering with the cardioprotective effect of pre- and postconditioning. The aim of this review is to show the potential for developing cardioprotective drugs on the basis of endogenous cardioprotection by pre- and postconditioning (i.e., drug applied as trigger or to activate signaling pathways associated with endogenous cardioprotection) and to review the evidence that comorbidities and aging accompanying coronary disease modify responses to ischemia/reperfusion and the cardioprotection conferred by preconditioning and postconditioning. We emphasize the critical need for more detailed and mechanistic preclinical studies that examine car-dioprotection specifically in relation to complicating disease states. These are now essential to maximize the likelihood of successful development of rational approaches to therapeutic protection for the majority of patients with ischemic heart disease who are aged and/or have modifying comorbid conditions.

Ischemic Preconditioning: Implications for the Geriatric Heart

Ischemic preconditioning is among the most consistent and powerful modes of reducing myocardial infarct size. Although several clinical studies have suggested that the human heart can be preconditioned, controversy exists in both the experimental and clinical literature as to whether the senescent heart can be preconditioned. The authors recently reported that older patients (> or = 60 years of age) in the Thrombolysis in Myocardial Infarction-4 study appeared to benefit from a history of angina prior to acute myocardial infarction. This observation may lead to a clinical counterpart to successful preconditioning in the older heart.

Effect of preinfarction angina pectoris on myocardial blush grade after reperfusion in first anterior wall acute myocardial infarction

BACKGROUND

The aim of the present study was to clarify the effect of preinfarction angina pectoris (PIA) on myocardial blush grade (MBG), a simple marker of myocardial tissue-level reperfusion, in acute myocardial infarction (AMI).

METHODS AND RESULTS

One hundred forty-two patients with first anterior wall AMI who were admitted within 6 h after onset of symptoms were examined. PIA was defined as typical chest pain within 48 h before onset of symptoms. MBG was evaluated by coronary angiography after reperfusion. Patients with MBG 2 or 3 (n=103) had a higher frequency of PIA and a lower frequency of diabetes mellitus than those with MBG 0 or 1 (n=39) (57% vs 28%, p=0.004, and 23% vs 44%, p=0.03, respectively). The former had a lower peak creatine kinase level and a greater left ventricular ejection fraction at predischarge than the latter (3,652+/-2,440 vs 5,507+/-3,058 IU/L, p=0.0002, and 57+/-12% vs 45+/-11%, p<0.0001, respectively). Multivariate logistic regression analysis showed that PIA (p=0.004) and diabetes mellitus (p=0.03) were independently associated with MBG 2 or 3 after reperfusion.

CONCLUSIONS

PIA has beneficial effects on myocardial tissue-level reperfusion evaluated by MBG in first anterior wall AMI.

Ischemic preconditioning and preinfarction angina in the clinical arena

In animals, brief episodes of ischemia before a total coronary occlusion protect the heart and result in a smaller myocardial infarct size. In humans, episodes of angina before acute myocardial infarction might also confer a preconditioning or protective effect; numerous studies show that preinfarction angina is associated with smaller infarcts. Preinfarction angina is also associated with reductions in ventricular dysfunction, arrhythmias and incidence of no-reflow phenomena, and, in some cases, improved survival. The protective effect of preconditioning in humans is characterized by marked individual variations and seems to be attenuated in women, people with diabetes and the elderly. Exercise seems to be an important way to induce preconditioning in humans and preserves it in the elderly.

A phase of increased ST elevation during coronary occlusion following ischemic preconditioning

ATP-sensitive potassium channels are opened during the course of ischemic preconditioning (IP). As experimental data suggest that opening of sarcolemmal ATP-sensitive potassium channels underlie ST elevation during myocardial ischemia, one would expect to observe increased ST elevation during ischemia following IP. However, clinical studies have reported IP to attenuate ST elevation during repeated brief coronary occlusions. The objective of this study was to characterize the temporal course of ST elevation during coronary occlusion following IP. Twenty-eight closed-chest pigs were subject to catheter-based left anterior descending coronary artery occlusion/ reperfusion for 45/120 minutes. Thirteen animals were preconditioned by two occlusion/reperfusion cycles of 10/30 minutes. Fifteen pigs served as controls. The electrocardiographic ST vector magnitude was continuously monitored. IP reduced the infarct size normalized for area at risk (IP 9.6 +/- 15.8%; control 71.2 +/- 14.7%; p < 0.001). IP increased the time between coronary artery occlusion and appearance of significant rise in ST vector magnitude from 51 +/- 17 to 94 +/- 33 seconds (p < 0.01). IP reduced the rise in ST vector magnitude after 120 seconds of occlusion from 202 +/- 85 microV to 68 +/- 28 microV (p < 0.001) and increased the rise in ST vector magnitude after 600 seconds from 265 +/- 106 microV to 427 +/- 232 microV (p < 0.001).

CONCLUSION

Ischemic preconditioning reduced and delayed early ST elevation during subsequent coronary artery occlusion, but increased late ST elevation. Thus, ischemic preconditioning causes a dynamic and critically time-dependent biphasic pattern of ST elevation during repeated coronary occlusions.

Prognostic value of serum amyloid A protein in patients with acute myocardial infarction

BACKGROUND

The relationship between plasma levels of serum amyloid A protein (SAA) concentrations and clinical course (including mortality) was investigated in patients with acute myocardial infarction (AMI).

METHODS AND RESULTS

The study enrolled 280 consecutive AMI patients who were admitted within 10 h of onset and were successfully reperfused by primary percutaneous coronary intervention. Plasma SAA concentrations were evaluated at 24 h after onset. The threshold of the upper quintile (325 mug/dl) was used to divide patients into 2 groups: either a high SAA (H group: > or =325 mug/dl; n=56) or low SAA (L group: <325 microg/dl; n=224). (I) Left ventricular (LV) ejection fraction in the chronic phase was significantly less in the H group than in the L group (52+/-14% vs 57+/-13%, p=0.03). (II) There were significantly more major complications in the H group than in the L group (cardiac rupture: p=0.0007, cardiogenic shock: p<0.0001; subacute thrombosis: p=0.0007; cardiac death: p=0.0003). (III) Multivariate analysis identified SAA as an independent predictor of 6-month mortality in AMI patients (risk ratio: 5.8, 95%confidence interval: 1.3-27.7, p=0.03).

CONCLUSIONS

In the setting of AMI, plasma SAA concentrations may be closely related to LV systolic dysfunction and poor patient outcomes, including mortality.

Prognostic significance of time-delay to peak creatine kinase after direct percutaneous coronary intervention in acute myocardial infarction patients

The aim of the present study was to investigate the prognostic significance of time-delay to peak creatine kinase (CK) after successful direct percutaneous coronary intervention (PCI) in patients with acute myocardial infarction (AMI). Our 240 consecutive first AMI attack subjects admitted within 5 hours from onset were successfully reperfused by direct PCI therapy. Subjects were divided into two groups according to the upper quartile value of peak-CK time from onset, the early peak-CK group (peak-CK time < or = 16 hours from onset, n = 180) and the late peak-CK group (peak-CK time > 16 hours, n = 60). (I) The early ST-segment resolution rate was lower in the late peak-CK group compared with the early peak-CK group (P < 0.05), and there were significantly fewer patients with preinfarction angina pectoris in the late peak-CK group than in the early peak-CK group (P < 0.01). (II) LVEF in the chronic stage was significantly lower in the late peak-CK group than in the early peak-CK group (49 +/- 13% versus 57 +/- 13%, P < 0.001). (III) There were significantly more patients with major complications in the late peak-CK group than in the early peak-CK group (required CABG: 10% versus 3%, P < 0.05; cardiac death: 18% versus 3%, P = 0.0001). (IV) Multivariate analysis identified late peak-CK as an independent predictor of cardiac death (Odds ratio 7.91, 95% C.I. 1.40-44.11, P < 0.05). In patients with AMI, the time-delay to peak-CK after successful direct PCI may be closely related to left-ventricular systolic dysfunction and poor patient outcome, including mortality.

Reperfusion phenomenon is a strong predictor of left ventricular remodeling after acute myocardial infarction

BACKGROUND

Many clinicians have seen the reperfusion phenomenon, a paradoxical response that includes a transient increase of chest pain, additional ST-segment elevation or ventricular arrhythmias immediately after coronary reperfusion, in patients with acute myocardial infarction (AMI). The aim of the present study was to investigate the impact of this phenomenon during coronary reperfusion on left ventricular (LV) remodeling in patients with AMI.

METHODS AND RESULTS

One hundred and thirty-eight consecutive patients with a first anterior-wall AMI, undergoing coronary reperfusion treatment within 24 h of onset were prospectively evaluated for reperfusion phenomenon and followed up with scheduled evaluations of LV function and morphology with left ventriculography for 1 year. Of the 138 enrolled patients, 77 underwent serial left ventriculography at the acute, subacute and 1-year phases. Of these 77 patients, 39 demonstrated the reperfusion phenomenon. The LV end-diastolic volume index significantly increased from the acute to subacute phase and to the 1-year phase, but was unchanged in the 38 patients without reperfusion phenomenon. In multivariate analysis, reperfusion phenomenon was the only determinant of LV dilatation after AMI.

CONCLUSIONS

Reperfusion phenomenon was a strong predictor of LV remodeling after reperfusion therapy for AMI.

Preconditioning with sevoflurane decreases PECAM-1 expression and improves one-year cardiovascular outcome in coronary artery bypass graft surgery

BACKGROUND

Cardiac preconditioning is thought to be involved in the observed decreased coronary artery reocclusion rate in patients with angina preceding myocardial infarction. We prospectively examined whether preconditioning by sevoflurane would decrease late cardiac events in patients undergoing coronary artery bypass graft (CABG) surgery.

METHODS

Seventy-two patients scheduled for elective CABG surgery were randomized to preconditioning by sevoflurane (10 min at 4 vol%) or placebo. For all patients, follow-up of adverse cardiac events was obtained 6 and 12 months after surgery. Transcript levels for platelet-endothelial cell adhesion molecule-1 (PECAM-1/CD31), catalase and heat shock protein 70 (Hsp70) were determined in atrial biopsies after sevoflurane preconditioning.

RESULTS

Pharmacological preconditioning by sevoflurane reduced the incidence of late cardiac events during the first year after CABG surgery (sevoflurane 3% vs 17% in the placebo group, log-rank test, P=0.038). One patient in the sevoflurane group and three patients in the placebo group experienced new episodes of congestive heart failure and three additional patients had coronary artery reocclusion. Perioperative peak concentrations for myocardial injury markers were higher in patients with subsequent late cardiac events [NTproBNP, 9031 (4125) vs 3049 (1906) ng litre(-1), P<0.001; cTnT, 1.31 (0.88) vs 0.46 (0.29) microg litre(-1), P<0.001]. Transcript levels were reduced for PECAM-1 and increased for catalase but unchanged for Hsp70 in atrial biopsies after sevoflurane preconditioning.

CONCLUSIONS

This prospective randomized clinical study provides evidence of a protective role for pharmacological preconditioning by sevoflurane in late cardiac events in CABG patients, which may be related to favourable transcriptional changes in pro- and antiprotective proteins.

Preinfarction angina does not alter infarct size and in hospital outcome after acute myocardial infarction with ST elevation

BACKGROUND

Preinfarction angina has been reported to limit infarct size, in a manner analogous to experimental preconditioning. However, other studies have reported inconsistent results. We aimed to investigate prospectively the role of preinfarction angina on infarct size and in hospital outcome.

METHODS

Ninety-nine patients were divided into three groups according to the timing of angina: the group "< 48 h" reported angina within the last 48 h, the group "> 48 h" earlier than 48 h and the group "acute" no angina before infarction. Myocardial injury was estimated by creatine kinase, creatine kinase-MB, troponin I and C-reactive protein. In hospital events included death, recurrent ischemia, congestive heart failure and atrioventricular block.

RESULTS

Clinical characteristics, thrombolysis administration and the magnitude of enzymes released were not statistically different among the three groups: peak creatine kinase was 2139+/-1714 U/l for the >48 h group, vs. 2344+/-1634 U/l for the acute group, vs. 2209+/-1384 U/l for the <48 h group (p=0.88). Peak creatine kinase-MB was 124+/-104 U/l for the >48 h group, vs. 168+/-182 U/l for the acute group, vs. 154+/-108 U/l for the <48 h group (p=0.62). Peak troponin I, peak C-reactive protein and in hospital outcome also did not differ statistically in the three groups; p=0.5, p=0.45.

CONCLUSIONS

Infarct size estimated by cardiac enzymes and by the marker of C-reactive protein, as well as in hospital clinical prognosis are not different in patients with and without preinfarction angina. It seems, therefore, that preinfarction angina confers ischemic conditions inadequate to mimic preconditioning.

Preconditioning reduces QTc value in patients with first non-ST-segment elevation myocardial infarction (NSTEMI)

BACKGROUND

Preinfarction angina (PA) consists a strong clinical correlate to ischemic preconditioning (PC) and seems to occur in a bimodal time course. The aim of the study is to evaluate the impact of both forms of PC on QTc value representing myocardial electric stability, in patients with a first NSTEMI.

METHODS

Forty-eight patients, with first NSTEMI and poor or no collateral development were enrolled in the study. QTc at admission and discharge were recorded. All patients had comparable admission QTc values and were divided into three groups according to the absence or presence and exact timing of preinfarction angina. The first group consisted of 20 patients who did not report PA (PA-, representing no PC effect); the second group of 12 patients with reported PA within 12 hours prior to admission (12h PA+, representing the classic form of PC); and the third group of 16 patients reporting PA within 12 to 48 hours prior to admission (48-hour PA+, representing the delayed form of PC). The primary outcome was determined as the effect of PA on QTc value at discharge.

RESULTS

Discharge QTc values were significantly reduced in both (PA+) groups compared to (PA-) group (412 +/- 50 vs. 455 +/- 53 ms, p = 0.015 and 417 +/- 29 vs. 455 +/- 53 ms, P = 0.033, respectively). Both groups of (PA+) patients compared to (PA-) patients suffered no arrhythmic events during their hospitalization (0/12 vs. 6/20, P = 0.04 and 0/16 vs. 6/20, P = 0.02).

CONCLUSIONS

Both forms of preconditioning, similarly and significantly reduce QTc value at discharge in patients experiencing a first NSTEMI, suggesting possible protection from future arrhythmic events.

Coronary blood flow in evolving myocardial infarction preceded by preinfarction angina: a critical reevaluation of preconditioning effects in clinical cases

This study was undertaken to reevaluate the protective effects of preinfarction (pre-MI) angina in acute MI. The mechanisms involved in the apparent protective effects of pre-MI angina have been presumed to be preconditioning effects as defined by experimental studies. The phenomenon, has not, however, been observed in diabetic and/or elderly patients or in those treated by primary percutaneous coronary intervention (PCI). A total of 202 patients with anterior wall MI without a history of MI who underwent primary PCI with coronary balloon dilation and stenting (rate: 50%) <6 hours after onset were studied. Patients included 59 with pre-MI angina (group 1) and 143 without pre-MI angina (group 2). The infarct-related coronary artery was patent on admission in 46% of group 1 and 31% of group 2 (p=0.045). Thrombolysis in Myocardial Infarction (TIMI) 1-2 flow was significantly more frequent in group 1 (29%) than in group 2 (11%, p=0.005) on admission. Among risk factors, clinical background, coronary anatomy, and clinical outcome, the only significant predictor of pre-MI angina was a patent infarct-related coronary artery on admission (odds ratio: 2.39, p = 0.015). There was no significant difference in left ventricular ejection fraction, peak creatine kinase, or the incidences of heart failure and in-hospital/follow-up deaths between these groups. In conclusion, the findings suggest that the protective effects reported in MI with pre-MI angina treated by thrombolysis are due to more fragile thrombotic occlusion, which can be more easily recanalized by thrombolysis, whereas the beneficial effects are not evident in those treated by primary PCI.

Association Between Serum C-Reactive Protein Elevation and Left Ventricular Thrombus Formation After First Anterior Myocardial Infarction

STUDY OBJECTIVES

Most left ventricular (LV) thrombi that occur after acute myocardial infarction (AMI) are formed within 2 weeks, when inflammatory cells have infiltrated into the necrotic myocardium. Inflammatory changes on the endocardial surface may induce platelet deposition and fibrin net formation through interaction with proinflammatory cytokines. We sought to determine the significance of the inflammatory response reflected by serum C-reactive protein (CRP) elevation in LV thrombus formation after AMI.

DESIGN

We examined 160 patients with first anterior AMI. Peak serum creatine kinase (CK) and CRP levels were determined by serial measurements. Echocardiography was performed 10 to 14 days after the onset. We assessed the association between the elevation of serum CRP levels and LV thrombus formation after AMI.

RESULTS

LV thrombus was observed in 13 patients (8%). There was no difference in age, sex, coronary risk factors, preinfarction angina, use of revascularization therapy and anticoagulant therapy, platelet count, and fibrinogen level on hospital admission between the two groups. The mean (+/- SD) peak serum CRP level was markedly increased in patients with LV thrombus compared to those without (18.0 +/- 12.6 vs 9.4 +/- 8.1 mg/dL; p = 0.001), despite their having similar peak CK levels. Multivariate analysis showed that a peak CRP level of > or =20 mg/dL was an independent predictor of thrombus formation (relative risk, 4.82; p = 0.037) among variables including older age (> or =60 years old), peak CK level (> or =3,000 IU/L), and peak WBC count (> or =12,000 cells/ microL).

CONCLUSION

A greater elevation of serum CRP level was associated with a higher incidence of LV thrombus after AMI, suggesting an important role of the inflammatory response in mural thrombus formation.

Evidence of ischemic preconditioning in patients experiencing first non-ST-segment elevation myocardial infarction (NSTEMI)

BACKGROUND

Several studies have demonstrated the protective effects of preinfarction angina in Q wave myocardial infarction, implicating the role of ischemic preconditioning but this role remains uncertain in patients with a NSTEMI. Subendocardial viability in NSTEMI patients, is thought to be less dependent on collateral circulation and thus more likely to be protected by other mechanisms such as preconditioning.

METHODS

We have studied prospectively 40 patients with first NSTEMI and with angiographically proven poor or no collateral development and compared two groups; those with versus those without preinfarction angina. All in-hospital events, such as recurrent angina, congestive heart failure, arrhythmias and reinfarction were recorded. Serum markers of myocardial necrosis (CPK, CPK-MB, AST) and discharge QTc values were estimated.

RESULTS

Preconditioned patients suffered less recurrent angina (18 vs. 55% P=0.014), congestive heart failure (0 vs. 22%, P=0.02), arrhythmic events (0 vs. 27%, P=0.008) and had significant smaller values of mean peak CPK (381 +/- 152 vs. 859 +/- 496 I.U./l, P=0.0008), mean peak CPK-MB (45.5 +/- 24.6 vs. 105.2 +/- 87 I.U./l, P=0.01), mean peak AST (59.8 +/- 23.1 vs. 112.4 +/- 64.3 I.U./l, P=0.003) and QTc value at discharge (0.42 +/- 0.03 vs. 0.46 +/- 0.05 s, P=0.005) than patients without preconditioning. Multiple logistic regression analysis confirmed that the absence of preinfarction angina (relative risk 9.10, 95% CI 2.08-40.00, P=0.003) was a significant predictor of in-hospital complications.

CONCLUSIONS

Preinfarction angina constitutes a strong clinical correlate to ischemic preconditioning in patients with first NSTEMI, offering serious protection, by improving in-hospital outcome and reducing infarct size.

Preconditioning the Myocardium: From Cellular Physiology to Clinical Cardiology

Yellon, Derek M., and James M. Downey. Preconditioning the Myocardium: From Cellular Physiology to Clinical Cardiology. Physiol Rev 83: 1113-1151, 2003; 10.1152/physrev.00009.2003.—The phenomenon of ischemic preconditioning, in which a period of sublethal ischemia can profoundly protect the cell from infarction during a subsequent ischemic insult, has been responsible for an enormous amount of research over the last 15 years. Ischemic preconditioning is associated with two forms of protection: a classical form lasting ∼2 h after the preconditioning ischemia followed a day later by a second window of protection lasting ∼3 days. Both types of preconditioning share similarities in that the preconditioning ischemia provokes the release of several autacoids that trigger protection by occupying cell surface receptors. Receptor occupancy activates complex signaling cascades which during the lethal ischemia converge on one or more end-effectors to mediate the protection. The end-effectors so far have eluded identification, although a number have been proposed. A range of different pharmacological agents that activate the signaling cascades at the various levels can mimic ischemic preconditioning leading to the hope that specific therapeutic agents can be designed to exploit the profound protection seen with ischemic preconditioning. This review examines, in detail, the complex mechanisms associated with both forms of preconditioning as well as discusses the possibility to exploit this phenomenon in the clinical setting. As our understanding of the mechanisms associated with preconditioning are unravelled, we believe we can look forward to the development of new therapeutic agents with novel mechanisms of action that can supplement current treatment options for patients threatened with acute myocardial infarction.

Assessment of left ventricular systolic and diastolic function by doppler tissue imaging in patients with preinfarction angina

BACKGROUND

The aim of this study was assessment of left ventricular (LV) systolic and diastolic function by pulsed wave Doppler tissue imaging (DTI) in patients with or without preinfarction angina in acute myocardial infarction.

METHODS

We prospectively evaluated 31 consecutive patients (4 women, 27 men; age 58 +/- 10 years) with a first acute myocardial infarction. LV systolic and diastolic function was assessed by classic methods and DTI on the third day during acute myocardial infarction. Patients were divided into 2 groups according to the presence (group 1; n = 10) or absence (group 2; n = 21) of preinfarction angina. Mitral inflow velocities and early diastolic mitral annular velocity (Em), late diastolic mitral annular velocity (Am), peak systolic mitral annular velocity, Em/Am, the ratio of early diastolic mitral inflow velocity (E) to Em, and myocardial performance index were calculated by DTI.

RESULTS

Group 1 had significantly higher Em and Em/Am than group 2 (11.3 +/- 3.34 cm/s vs 7.4 +/- 2.07 cm/s, P <.0001; 1.01 +/- 0.38 cm/s vs 0.6 +/- 0.2 cm/s, P =.001, respectively). The E/Em ratio and myocardial performance index were significantly lower in group 1 than in group 2 (5.1 +/- 2.92 vs 8.10 +/- 3.15, P=.018; 0.49 +/- 0.15 vs 0.65 +/- 0.24, P =.042, respectively). Wall-motion score index was lower in those with preinfarction angina than in those without (1.6 +/- 0.36 vs 1.9 +/- 0.39; P =.04, respectively). Peak systolic mitral annular velocity and Am were not statistically different between groups (9.4 +/- 1.84 vs 8.3 +/- 2.03, P =.172; 11.7 +/- 3.07 vs 12.1 +/- 3.34, P =.72, respectively). There were no significant differences between the 2 groups regarding transmitral E velocity, atrial contraction mitral inflow velocity (A), E/A ratio, isovolumetric relaxation time, and deceleration time of the mitral E wave (P =.91, P =.08, P =.58, P =.81, and P =.71, respectively).

CONCLUSION

LV diastolic function was better in patients with preinfarction angina than in patients without. This condition could not be detected by conventional mitral inflow Doppler velocities, but could be detected by DTI. This preliminary evidence shows that DTI is better than conventional mitral Doppler indices in the assessment of a favorable LV diastolic function in patients with preinfarction angina.

Effects of preinfarction angina pectoris on infarct size and in-hospital mortality after coronary intervention for acute myocardial infarction

We studied the effect of preinfarction angina on in-hospital outcomes after percutaneous coronary intervention for anterior and nonanterior acute myocardial infarction. Beneficial effects of preinfarction angina on infarct size and in-hospital outcome are evident in patients with anterior infarction, but not in those with nonanterior infarction.

Early use of beta-blockers is associated with attenuation of serum C-reactive protein elevation and favorable short-term prognosis after acute myocardial infarction

BACKGROUND

We have reported that a marked elevation in serum C-reactive protein (CRP) level is a predictor for infarct expansion and cardiac rupture after AMI. Although beta-blockers prevent cardiac rupture after AMI, their effect on serum CRP elevation has not been determined.

METHODS

We studied a total of 154 patients with first Q-wave AMI. Patients complicated by pump failure were excluded from this study. Eighty-two patients received beta-blocker treatment within 24 h of the onset of AMI, while 72 patients received no beta-blocker treatment. Peak serum creatine kinase (CK) and CRP levels were determined by serial measurements.

RESULTS

There was no difference between the groups according to age, sex, coronary risk factors, pre-infarction angina, infarct site, prior use of cardiovascular drugs, use of revascularization therapy, and prevalence of multivessel disease. Beta-blocker treatment was associated with a lower peak CRP level (6.9 +/- 6.1 vs.10.8 +/- 9.3 mg/dl, p = 0.002), a shorter duration from the onset to the peak CRP level (2 +/- 1 vs. 3 +/- 2 days, p < 0.0001), a lower incidence of cardiac rupture (p = 0.03) and lower in-hospital cardiac mortality (p = 0.02), despite similar peak CK levels.

CONCLUSION

The early use of beta-blockers is associated with decreased serum CRP level and a favorable clinical outcome after first Q-wave AMI, suggesting some beneficial effects of beta-blockers on infarct healing after AMI.

Mechanical complications after myocardial infarction reliably predicted using C-reactive protein levels and lymphocytopenia

We assessed the accuracy of C-reactive protein (CRP) levels and lymphocyte counts to predict a mechanical complication (MC) after myocardial infarction (MI). Within 10 years, we identified 36 patients with 39 echocardiographically confirmed MC within 30 days of MI: ventricular septal defect (17 cases), papillary muscle rupture (10 cases), and left ventricular free wall rupture (12 cases). They were compared to 41 controls with an uncomplicated hospital course after MI. Peak CRP levels and minimum relative lymphocyte counts obtained within 96 h of the acute MI (AMI) and before diagnosis of the complication were compared with clinical parameters. Prior to the MC, peak CRP levels were significantly higher (p < 0.001) and relative lymphocyte counts lower (p < 0.001) than in controls while creatine kinase levels did not differ (p = nonsignificant). Using multivariate logistic regression, the following score was identified to have excellent prognostic significance for MC: CRP (mg/l) - 10 x Lyc (%). The area under the receiver-operating characteristic curve was 0.90 +/- 0.05 (p < 0.001). Combined use of CRP levels and relative lymphocyte counts may be helpful in accurately predicting an MC after AMI and should therefore be routinely assessed.

Reduced microvascular and myocardial damage in patients with acute myocardial infarction and preinfarction angina

BACKGROUND

After acute myocardial infarction, the presence of ischemic preconditioning as a result of preinfarction angina has a protective role, limiting necrosis extent and guaranteeing greater myocardial functional recovery. The relationship between preinfarction angina, microvascular reflow, and myocardial function is poorly known. We hypothesized that after acute myocardial infarction patients with preinfarction angina have both microvascular integrity and myocardial function preservation.

METHODS AND RESULTS

In 51 patients with a first acute myocardial infarction, we noninvasively assessed microvascular perfusion and coronary flow reserve with intravenous myocardial contrast echocardiography and investigated myocardial contractile recovery with low-dose dobutamine and 90-day follow-up echocardiography. Typical angina was present in 25 patients and absent in 26 patients during the 7 days preceding the myocardial infarction. Compared with those patients without preinfarction angina, patients with preinfarction angina showed a greater microvascular reflow extent and coronary flow reserve (respectively, 25.2% +/- 22.8% vs 48.3% +/- 23.3%, P <.05, and 3.44 +/- 0.75 vs 1.95 +/- 0.67, P <.0001), a better regional myocardial function, as expressed with wall motion score index in the risk area at dobutamine (1.67 +/- 0.61 vs 2.10 +/- 0.43, P <.005) and at follow-up (1.72 +/- 0.56 vs 2.22 +/- 0.40, P <.0001) echocardiogram, despite being similar in the first echocardiogram (2.60 +/- 0.28 vs 2.63 +/- 0.28, P = not significant), and significantly less pronounced left ventricular dilation at follow-up.

CONCLUSION

Presence of preinfarction angina, because of the preconditioning effect, reduces myocardial damage and favors myocardial viability, limiting left ventricular remodeling. This beneficial effect seems to be at least partly mediated by the more preserved microvascular integrity and functional vasodilation after acute myocardial infarction.

Effect of preinfarction angina pectoris on ST-segment resolution after primary coronary angioplasty for acute myocardial infarction

The presence of preinfarction angina has been shown to exert a favorable effect on left ventricular function after acute myocardial infarction (AMI). Whether or not preinfarction angina is beneficial for myocardial tissue reperfusion, however, remains to be determined. We sought to evaluate the influence of preinfarction angina on resolution of ST-segment elevation, which could be affected by microcirculatory damage after recanalization therapy. We studied 96 patients with a first AMI in whom Thrombolysis In Myocardial Infarction (TIMI)-3 flow in the infarct-related artery was established by primary angioplasty. Percent reduction in the sum of ST elevation from baseline to 1 hour after angioplasty (percent delta summation operator ST) was examined. Poor ST resolution, defined as percent delta summation operator ST <50%, was observed in 25 patients, who had a worse clinical outcome, larger infarct size, and poorer left ventricular function. On multivariate analysis, the absence of preinfarction angina, as well as anterior wall infarction, were major independent predictors of poor ST resolution, whereas age, sex, coronary risk factors, ischemic time, Killip class on admission, multivessel disease, initial TIMI flow grade, and extent of collaterals were not significant. Patients with preinfarction angina had a greater degree of ST-segment resolution than those without angina (71 +/- 21% vs 49 +/- 43%, p = 0.02). Additional ST elevation after reperfusion was noted exclusively in patients without preinfarction angina (p = 0.02). Preinfarction angina is associated with a greater degree of ST-segment resolution in patients with TIMI-3 flow after primary angioplasty, suggesting a protective effect of preinfarction angina against microcirculatory damage after reperfusion.