Reperfusion In Myocardial Infarction Research Articles

Impact of door-to-balloon time on long-term mortality in high- and low-risk patients with ST-elevation myocardial infarction

BackgroundDoor-to-balloon time (DTBT) less than 90min remains the benchmark of timely reperfusion in ST-elevation myocardial infarction (STEMI). The relative long-term benefit of timely reperfusion in STEMI patients with differing risk profiles is less certain. Thus, we aimed to assess the impact of DTBT on long-term mortality in high- and low-risk STEMI patients. MethodWe analysed baseline clinical and procedural characteristics of 2539 consecutive STEMI patients who underwent primary percutaneous coronary intervention (PCI) from the Melbourne Interventional Group registry from 2004 to 2012. Patients were classified high risk (HR-STEMI) if they presented with cardiogenic shock, out-of-hospital cardiac arrest (OHCA) or Killip class ≥2; or low-risk (LR-STEMI) if there were no high-risk features. We then stratified high- and low-risk patients by DTBT (≤90min vs. >90min) and assessed long-term mortality. ResultOf the 2539 patients, 395 (16%) met the high-risk criteria. A DTBT ≤90min was achieved in 43% of HR-STEMI patients and in 55% of LR-STEMI patients. Patients in the HR-STEMI compared to LR-STEMI cohort had higher in-hospital (31% vs. 1%, p<0.01) and long-term mortality (37% vs. 7%, p<0.01). A DTBT ≤90min was associated with significant improvements in short- and long-term mortality in both groups. A DTBT ≤90min was an independent multivariate predictor of long-term survival in LR-STEMI (hazard ratio [HR] 0.5, 95% confidence interval [CI] 0.3–0.9, p=0.02) but not in HR-STEMI (HR 0.7, 95% CI 0.5–1.1, p=0.11). ConclusionA DTBT ≤90min was associated with improved short- and long-term outcomes in high- and low-risk STEMI patients. However, it was only an independent predictor of long-term survival in LR-STEMI patients.

O11-3 - Intramyocardial Hemorrhage Assessed by T2* Imaging is Associated with Myocardial Damage and May Predicts Long-Term Outcome in Patients with Acs

Microvascular obstruction (MVO) is recognized as one of complications of acute reperfused myocardial infarction (AMI). Recently it has been reported that intramyocardial hemorrhage (IMH) has the part of what had been recognized as MVO by T2* cardiovascular magnetic resonance imaging (CMR). We aimed to distinguish IMH within MVO and evaluate relationships between presence of IMH and disease severity in patients with AMI.Forty-five consecutive AMI patients that had undergone primary PCI were categorized into three groups whether the presence or absence of MVO and IMH. We assessed the values of MAX-CK, MAX-CKMB, LGE-volume, MVO-volume, TIMI-grade score and Blush-grade score in the acute phase, and LVEF, LVEDV, ESV, CI, and LV-mass in the chronic phase.There was statistically significant difference between the three groups regarding MAX-CK (6295.8 ± 3472.4, 2082.6 ± 854.4, 612.7 ± 337.9, P = .01), MAX-CKMB (365.8 ± 254.1, 200.2 ± 152.1, 55.1 ± 44.7, P = .01), LGE-volume (39.5 ± 20.0,17.2 ± 6.7, 5.2 ± 4.2, P = .01), and Blush-grade score (P = .015). In chronic phase, LVEF tended to be deteriorated in IMH(+) group, while IMH(-) group showed LVEF improvement. Furthermore, both LVEDV and ESV were increased in IMH(+) group, whereas both parameters were decreased in IMH(-) group.In conclusion, presence of intramyocardial hemorrhage revealed by T2* CMR indicates severe myocardial damage and may predicts worse outcome in patients with AMI.

Symptom-Onset-To-Balloon Time, ST-Segment Resolution and In-Hospital Mortality in Patients With ST-Segment Elevation Myocardial Infarction Undergoing Primary Percutaneous Coronary Intervention in China: From China Acute Myocardial Infarction Registry

Animal and imaging study evidence favors early reperfusion for acute myocardial infarction. However, in clinical trials, the effect of symptom-onset-to-balloon (S2B) time on clinical outcomes in patients with ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (pPCI) has been inconsistent. Moreover, there are few data regarding the ischemic time in China. A total of 3,877 consecutive patients with STEMI with available S2B time undergoing pPCI from January 2013 to September 2014 at 108 hospitals that participated in the China Acute Myocardial Infarction registry were included and stratified into 3 S2B groups: <6hours, 6 to 12hours, >12hours S2B time was tested in multivariate logistic regression analyses as an independent risk factor of mortality (primary outcome), major adverse cardiovascular and cerebrovascular events (MACCE), and impaired myocardial perfusion (secondary outcomes). The median S2B time was 5.5 (3.75 to 8.50) hours. Longer S2B time was associated with higher in-hospital mortality (<6hours: 2.7%; 6 to 12hours: 3.4%; >12hours: 4.9%; p= 0.047) and ST-segment resolution <50% (<6hours: 16.7%; 6 to 12hours: 19.2%; >12hours: 24.3%; p= 0.002) but not MACCE. In multivariate-adjusted analysis, S2B >12hours remained associated with ST-segment resolution <50% (odds ratio 1.53, 95% confidence interval 1.16 to 2.01, p= 0.002) but not with in-hospital mortality (odds ratio 1.673, 95% confidence interval 0.95 to 2.94, p= 0.073). In conclusion, median S2B time in patients with STEMI undergoing pPCI was longer than that in registry studies from other countries. Longer S2B time was associated with impaired myocardial perfusion but not with in-hospital mortality or MACCE.

Assessment of Changing Patterns of Hematological Indices and Their Effects on the Success of Primary Percutaneous Reperfusion in Acute Transmural Myocardial Infarction

Assessment of Changing Patterns of Hematological Indices and Their Effects on the Success of Primary Percutaneous Reperfusion in Acute Transmural Myocardial Infarction

Characterisation of Myocardial Injury via T1 Mapping in Early Reperfused Myocardial Infarction and its Relationship with Global and Regional Diastolic Dysfunction.

Cardiovascular magnetic resonance (CMR) advances in imaging techniques, permits the ability to accurately characterise tissue injury post myocardial infarction. Pre-contrast T1 mapping enables this through measurement of pre-contrast T1 relaxation times. We investigate the relationship between T1 characterisation of myocardial injury with global and regional diastolic function. Revascularised acute myocardial infarction patients with normal left ventricular (LV) systolic function on TTE were assessed by 1.5T CMR. Acute regional diastolic wall motion abnormalities, global diastolic function measurements, acute segmental damage fraction with LGE and mean segmental pre-contrast T1 values were assessed on matching short axis slices. Forty-four patients were analysed. Mean LVEF was 62.1±9.4%. No difference between NSTEMI (22/44) and STEMI in mean pre-contrast T1 values of infarcted (1025.0±109.2 vs 1011.0±81.6ms, p=0.70), adjacent (948.3±45.3 vs 941.1±46.6ms, p=0.70) and remote (888.8±52.8 vs 881.2±54.5ms, p=0.66) segments was detected. There was no correlation between pre-contrast T1 of infarcted segments with global diastolic dysfunction (E/A, r2=0.216, p=0.06; S/D, r2=0.243, p=0.053; E/E', r2=0.240, p=0.072), but there was significantly positive, moderate correlation with circumferential diastolic strain rate, (r2=0.579, p<0.01) with excellent agreement and reproducibility. Cardiac magnetic resonance evaluation of pre-contrast T1 values revealed no difference between NSTEMI and STEMI patients in terms of tissue characterisation post-myocardial infarction. However, pre-contrast T1 of infarcted tissue is significantly correlated with regional diastolic circumferential strain rate.

Up-regulation of miRNA-221 inhibits hypoxia/reoxygenation-induced autophagy through the DDIT4/mTORC1 and Tp53inp1/p62 pathways

Timely reperfusion in acute myocardial infarction has improved clinical outcomes but the benefits are partially offset by ischemia-reperfusion injury (I/R). MiRNA regulates mRNA of multiple effectors within injury and survival cell signaling pathways. We have previously reported the protective effects of miRNA-221 in I/R injury. The purpose of this study was to explore the mechanisms underlying cardioprotection of miR-221. Myoblast H9c2 and neonatal rat ventricular myocytes (NRVM) were subjected to 0.2% O2 hypoxia followed by 2 h of re-oxygenation (H/R). In gain-and-loss function studies through transfections of miR-221 mimic (miR-221) and inhibitor (miR-221-i), the protective effects of miR-221 were confirmed as assessed by increased cell metabolic activity (WST-1) and decreased LDH release. Autophagy was assessed by GFP-LC3 labeling of autophagosome formation, LC3 and p62 measurements. Co-immuno-precipitation and specific gene cloning and function were used to identify the pathways underpinning miR-221 effects. MiR-221 significantly reduced H/R injury in association with inhibition of autophagy. Underlying mechanisms include (1) down-regulation of Ddit4 (disinhibiting the mTORC1/p-4EBP1 pathway) which inhibits autophagosome formation (2) down-regulation of Tp53inp1 (with reduced Tp53inp1/p62 complex formation) which inhibits autophagosome degradation. In conclusion, miRNA-221 exerts cytoprotective effects in hypoxia-reoxygenation injury in association with alterations in autophagic cell injury. Mir-221 may constitute is a novel therapeutic target in the treatment of cardiac I/R injury.

ACCURACY OF INTERPRETING FAX TO EMAIL ST-ELEVATION MYOCARDIAL INFARCTION ELECTROCARDIOGRAMS VIEWED ON SMARTPHONES

Timely review and interpretation of 12-lead electrocardiogram (ECG) reduces the time to reperfusion in acute ST-segment elevation myocardial infarction (STEMI). Smartphones are becoming an integral part of a wide variety of medical disciplines, and may be an ideal tool for timely assessment of ECG

REPERFUSION WITH INTRACORONARY THROMBOLYSIS AFTER FAILED ASPIRATION IN A PATIENT WITH ST ELEVATION MYOCARDIAL INFARCTION

Percutaneous intervention with stent placement is the preferred strategy of reperfusion in ST elevation myocardial infarction (STEMI). Insufficient results might be encountered if massive intracoronary thrombus and unfavorable anatomy are present. Intracoronary thrombolysis might improve reperfusion

Nitric oxide treatments as adjuncts to reperfusion in acute myocardial infarction: a systematic review of experimental and clinical studies

Unmodified reperfusion therapy for acute myocardial infarction (AMI) is associated with irreversible myocardial injury beyond that sustained during ischemia. Studies in experimental models of ischemia/reperfusion and in humans undergoing reperfusion therapy for AMI have examined potential beneficial effects of nitric oxide (NO) supplemented at the time of reperfusion. Using a rigorous systematic search approach, we have identified and critically evaluated all the relevant experimental and clinical literature to assess whether exogenous NO given at reperfusion can limit infarct size. An inclusive search strategy was undertaken to identify all in vivo experimental animal and clinical human studies published in the period 1990–2014 where NO gas, nitrite, nitrate or NO donors were given to ameliorate reperfusion injury. Articles were screened at title and subsequently at abstract level, followed by objective full text analysis using a critical appraisal tool. In twenty-one animal studies, all NO treatments except nitroglycerin afforded protection against measures of reperfusion injury, including infarct size, creatinine kinase release, neutrophil accumulation and cardiac dysfunction. In three human AMI RCT’s, there was no consistent evidence of infarct limitation associated with NO treatment as an adjunct to reperfusion. Despite experimental evidence that most NO treatments can reduce infarct size when given as adjuncts to reperfusion, the value of these interventions in clinical AMI is unproven. Our study raises issues for the design of further clinical studies and emphasises the need for improved design of animal studies to reflect more accurately the comorbidities and other confounding factors seen in clinical AMI.

Abstract TMP9: Hospitals' Performance on Timely Reperfusion in Stroke and Myocardial Infarction is not Correlated

Introduction: Timely reperfusion is performed less optimally in acute ischemic stroke (AIS) than in acute myocardial infarction (AMI). The degree to which hospital performance is correlated on emergent AMI and AIS care is unknown. Hypothesis: There would be a positive correlation between hospital performance on door-to-balloon time (D2B) for AMI and door-to-needle time (DTN) for AIS; and hospital performance on D2B would predict DTN even after controlling for patient and hospital differences. Methods: Prospective study of all hospitals participating in both Get With The Guidelines (GWTG)-Stroke and -Coronary Artery Disease from 2006-09 and treating ≥10 patients. We compared hospital-level DTN and D2B before and after risk adjustment using Spearman’s rank correlation coefficients and hierarchical linear regression modeling. We also correlated hospitals’ DTN and D2B data from 2013-14 using GWTG (DTN) and Hospital Compare (D2B). Results: There were 43 hospitals contributing data (1976 AIS and 59,823 AMI patients). Hospitals’ DTN times for AIS did not correlate with their D2B times for AMI (median DTN 85 min [IQR 77-99] vs. median D2B 72 min [IQR 62-81]; ρ=-0.09; p=0.55). There was no correlation between hospitals’ proportion of eligible patients treated within target time windows for AIS and AMI (median DTN&lt;60 minutes: 21% [IQR 11-30]; median D2B&lt;90 minutes: 68% [IQR 62-79]; ρ=-0.14; p=0.36). The lack of correlation between hospitals’ DTN and D2B times persisted after risk adjustment. From 2013-14, hospitals’ DTN performance in GWTG was not correlated with D2B performance in Hospital Compare (N=546 hospitals; see figure). Conclusions: We found no correlation between hospitals’ observed or risk-adjusted DTN and D2B times. Opportunities exist to improve hospitals’ performance of time-critical care processes for AIS and AMI in a coordinated rather than condition-specific manner.

Efficacy of Early Invasive Management After Fibrinolysis for ST-Segment Elevation Myocardial Infarction in Relation to Initial Troponin Status

BackgroundWe examined whether the efficacy of an early invasive strategy after fibrinolysis in ST-segment elevation myocardial infarction (STEMI) differs in relation to the initial troponin status. MethodsIn the Trial of Routine Angioplasty and Stenting After Fibrinolysis to Enhance Reperfusion in Acute Myocardial Infarction (TRANSFER-AMI), patients with STEMI presenting to a non-percutaneous coronary intervention (PCI)-capable hospital who received fibrinolysis were randomized to either a pharmacoinvasive or standard strategy for subsequent angiography and PCI. In this post hoc subgroup analysis, we compared the efficacy of these strategies in relation to the initial troponin status at hospital presentation for the primary composite end point of mortality, reinfarction, recurrent ischemia, heart failure, and cardiogenic shock at 30 days. We assessed the heterogeneity of treatment effect with initial troponin status using the Breslow-Day test and tested for interaction after adjustment for baseline Global Registry of Acute Coronary Events (GRACE) risk score. ResultsAmong 1059 patients, those with abnormal initial troponin levels (n = 514 [48.5%]) were older with worse Killip class, had a longer time from symptom onset to fibrinolysis, and had higher GRACE and Thrombolysis In Myocardial Infarction risk scores. Patients with abnormal troponin levels had higher rates of the primary end point (17.5% vs 10.8%; P = 0.002) and cumulative mortality or reinfarction at 1 year (14.0% vs 8.1%; P = 0.003). In stratified analyses, pharmacoinvasive management reduced the primary end point only among patients with normal initial troponin status. However, there was no significant treatment heterogeneity (all P ≥ 0.10) and no interaction between initial troponin status and treatment assignment after adjusting for GRACE risk score. ConclusionsPatients with STEMI and abnormal initial troponin levels had worse short-term and long-term outcomes. Accounting for overall baseline risk with the GRACE risk score, troponin status did not modulate the efficacy of pharmacoinvasive management.

Implications of ischaemic area at risk and mode of reperfusion in ST-elevation myocardial infarction

ObjectiveUncertainty exists concerning the relative merits of pharmacological versus mechanical coronary reperfusion in patients presenting early with ST-elevation myocardial infarction (STEMI) with extensive myocardium at risk. Accordingly, we investigated whether...

T2 mapping at 7T MRI can quantitatively assess intramyocardial hemorrhage in rats with acute reperfused myocardial infarction in vivo.

To investigate T2 mapping at 7T magnetic resonance imaging (MRI) for the detection and quantification of reperfused intramyocardial hemorrhage (IMH) in a rat model. Myocardial infarction (MI) was induced in 25 female rats. Rats were scanned at a 7T MRI 48 hours after reperfusion, using T2 mapping and late gadolinium enhancement imaging. Gross sections of the left ventricular myocardium and corresponding hematoxylin and eosin staining were assessed for IMH. T2 mapping images were matched with the gross sections. The IMH volume, expressed as a percentage of the left ventricular myocardial volume, of each heart determined by T2 mapping was compared with that calculated by pathological gross examination. Six rats died. In all, 97 gross sections of the left ventricular myocardium from the 19 rats were matched with T2 mapping images. IMH occurred pathologically in 68 gross sections, which was detected as hypointense cores by T2 mapping in 63 images (93% sensitivity). Three T2 mapping images with hypointense cores showed no hemorrhage on pathological sections (90% specificity). The positive and negative predictive values of hemorrhage on T2 mapping were 95% and 84%, respectively. In terms of the IMH volume, there was no significant difference between T2 mapping and pathological gross measurements (4.8 ± 2.4% vs. 5.3 ± 3.2%; P = 0.11). T2 mapping at 7T MRI can reliably detect and quantify IMH in rats in vivo. This may be useful as a noninvasive quantitative approach to investigating the mechanisms and evolution of MI and reperfusion injury. J. Magn. Reson. Imaging 2016;44:194-203.

Two-year follow-up data from the STEPP-AMI study: A prospective, observational, multicenter study comparing tenecteplase-facilitated PCI versus primary PCI in Indian patients with STEMI

BackgroundA pharmacoinvasive strategy may alleviate the logistical and geographical barriers in timely reperfusion of ST-segment elevation myocardial infarction (STEMI), especially in a developing country like India. AimTo assess the safety and efficacy of pharmacoinvasive strategy versus primary PCI in STEMI patients at 2 years. MethodsPatients enrolled in STEPP-AMI, an observational, multicenter, prospective study of 200 patients presenting with STEMI, were followed up for 2 years. Group ‘A’ comprised of patients with pharmacoinvasive strategy (n=45), and patients who underwent primary PCI (n=155) formed group ‘B’. Primary endpoint was composite of death, cardiogenic shock, reinfarction, repeat revascularization of the culprit artery, or congestive heart failure at 30 days, with follow-up till 2 years. ResultsThe primary endpoint occurred in 11.1% and 17.8% in group A and in 3.9% and 13.6% in group B, at 30 days and 2 years, respectively (p=0.07, RR=2.87; 95% CI: 0.92–8.97 at 30 days and p=0.47, RR=1.31; 95% CI: 0.62–2.76). There was no difference in bleeding risk between groups, 2.2% in group A and 0.6% in group B (‘p’=0.4). The infarct-related artery patency varied at angiogram; it was 82.2% in arm A and 22.6% in arm B (‘p’<0.001). In group A, failed fibrinolysis occurred in 12.1%. ConclusionA pharmacoinvasive strategy resulted in outcomes that were comparable with primary PCI at 2 years, suggesting it might be a viable option in India. Larger studies are required to confirm these findings.

An Observational study of prehospital and hospital delay in reperfusion for acute myocardial infarction at a University Hospital in India

Objective: Cardiovascular disease is the leading cause of death among Indian adults, and approximately 50% of deaths usually occur during the 1st hour after symptom onset before arriving at the hospital. A study was planned to evaluate the prehospital and hospital delay in patients with acute myocardial infarction (AMI). Methods: This was a prospective observational study of 390 patients with AMI admitted to the Department of Cardiology between March 2014 and August 2015. Detailed patient demographics, socioeconomic status, and prehospital and hospital delay were reviewed. Results: The mean age of presentation for male and female was 57 ± 12.91 and 61.5 ± 12.83 years, respectively. The mean prehospital delay, time to act after chest pain, and travel time were 9.08 ± 6.3, 7.16 ± 6.1, and 1.84 ± 0.8 h, respectively, and only three (9.7%) patients reached the hospital within 2 h after symptom onset. Out of 300 patients who received reperfusion therapy, thrombolysis was done in 276 (92%) patients while primary percutaneous coronary intervention was performed in only 24 (8%) patients. Mean door-to-needle (D-N) time and door-to-device time for those who received reperfusion therapy were 27.8 ± 4.3 and 78.95 ± 9.5 min, respectively. A multivariate logistic regression analysis revealed that the prehospital delay was significantly associated with older age, female sex, rural background, diabetes, having atypical pain, and lack of knowledge regarding the seriousness of chest pain. Conclusion: Approximately 79% of total prehospital delay was due to patient-related factors; old age, female sex, rural background, diabetes, atypical angina, and lack of knowledge being the significant attributes. D-N time and door-to-device time were within the limits of those recommended by current guidelines.

System Change to Deliver Timely Reperfusion for Myocardial Infarction in Regional New Zealand: The NMDHB STEMI Pathway Experience

Background: Delivery of timely reperfusion for ST elevation myocardial infarction (STEMI) remains a key target for healthcare delivery but lack of coordinated approach in regional NewZealand leads to low levels of revascularisation and poorer outcomes compared to metropolitan centres. Methods:NMDHB and St John have implemented a pathway for STEMI care including pre-hospital transmission of ECGs to a STEMI coordinator (Senior Emergency Department Doctor) responsible for coordinating reperfusion therapy and transport to Percutaneous Coronary Intervention (PCI) centre. Median(inter-quartile range) are reported. Results: In the ten months from 1 April 2015 to 31 January 2016, 78 patients presented with STEMI, the initial reperfusion strategy was 32(41%) for thrombolysis, 29(37%) PPCI and 17(22%) medical. First medical contact (FMC)-to-needle time was 71(65-102)minutes for the 34(45%) patients transported to hospital via ambulance compared to 25(17-38) minutes for those presenting directly to hospital. FMC to device time was 83(55-125)minutes for patients undergoing primary PCI. Of patients presenting to non-PCI centre (22%) who received thrombolysis as the primary treatment, FMC to helicopter activation was 46(29-70)minutes, door-in-door out (DIDO) time was 95(69-129)minutes and FMC to PCI centre was 147(130-198)minutes. Conclusion: Despite provision of a coordinated multidisciplinary pathway, timely reperfusion did not occur due to long transfer times and delayed activation of retrieval services. STEMI coordination requires expert input (ideally cardiologist) from FMC with provision for pre-hospital thrombolysis by paramedics where transport to a PCI capable centre is delayed beyond 60 minutes. Presently for regional patients, transfer times extend beyond where primary PCI could be reliably delivered.

Association of smoking with myocardial injury and clinical outcome in patients undergoing mechanical reperfusion for ST-elevation myocardial infarction

Association of smoking with myocardial injury and clinical outcome in patients undergoing mechanical reperfusion for ST-elevation myocardial infarction

Paramedic-initiated Helivac to Tertiary Hospital for Primary Percutaneous Coronary Intervention: A Strategy for Improving Treatment Delivery Times

Background: Delivery of timely reperfusion for ST elevation myocardial infarction (STEMI) remains a key target for healthcare delivery but lack of coordinated approach in regional NewZealand leads to low levels of revascularisation and poorer outcomes compared to metropolitan centres. Methods:NMDHB and St John have implemented a pathway for STEMI care including pre-hospital transmission of ECGs to a STEMI coordinator (Senior Emergency Department Doctor) responsible for coordinating reperfusion therapy and transport to Percutaneous Coronary Intervention (PCI) centre. Median(inter-quartile range) are reported. Results: In the ten months from 1 April 2015 to 31 January 2016, 78 patients presented with STEMI, the initial reperfusion strategy was 32(41%) for thrombolysis, 29(37%) PPCI and 17(22%) medical. First medical contact (FMC)-to-needle time was 71(65-102)minutes for the 34(45%) patients transported to hospital via ambulance compared to 25(17-38) minutes for those presenting directly to hospital. FMC to device time was 83(55-125)minutes for patients undergoing primary PCI. Of patients presenting to non-PCI centre (22%) who received thrombolysis as the primary treatment, FMC to helicopter activation was 46(29-70)minutes, door-in-door out (DIDO) time was 95(69-129)minutes and FMC to PCI centre was 147(130-198)minutes. Conclusion: Despite provision of a coordinated multidisciplinary pathway, timely reperfusion did not occur due to long transfer times and delayed activation of retrieval services. STEMI coordination requires expert input (ideally cardiologist) from FMC with provision for pre-hospital thrombolysis by paramedics where transport to a PCI capable centre is delayed beyond 60 minutes. Presently for regional patients, transfer times extend beyond where primary PCI could be reliably delivered.

Myocardial haemorrhage after acute reperfused ST-elevation myocardial infarction evolves progressively and contributes to the early bimodal pattern in T2-relaxation time: advanced imaging and clinical significance

Myocardial haemorrhage after acute reperfused ST-elevation myocardial infarction evolves progressively and contributes to the early bimodal pattern in T2-relaxation time: advanced imaging and clinical significance

Characterization of myocardial edema in rats with acute reperfused myocardial infarction at multiple time points by 7 T MR

Methods MI model was induced on 17 Sprague-Dawley rats (female, 260-280 g) by ligating the left anterior descending or circumflex coronary arteries for 60 minutes, followed by reperfusion. The rats were then scanned in a 7 T MRI system at 24 h, 48 h, 72 h, and 5 d after reperfusion. Area of ME and T2 values of ME were measured on T2 mapping images. Myocardial infarction was validated by the late gadolinium enhancement (LGE) method. IMH was detected by T2w. Repeated measures analysis of variance and independent sample t test were used for statistical analysis.