Epicardial adipose tissue, infarct size, microvascular obstruction and ventricular remodelling after ST-segment elevation myocardial infarction

Background

Epicardial adipose tissue (EAT) is a biologically active fat deposit contained beneath the pericardium promoting coronary atherosclerosis. EAT can be accurately measured through cardiac magnetic resonance (CMR), which also enables an accurate quantification of infarct size, microvascular obstruction (MVO), left ventricular (LV) ejection fraction (EF) and volumes in patients with ST-elevation myocardial infarction (STEMI).

Purpose

We performed a systematic assessment of the correlates of EAT volume at baseline and after 6 months in a homogeneous cohort of patients with STEMI.

Methods

We prospectively enrolled patients with a first anterior STEMI reperfused within 12 hours from symptom onset. These patients underwent a first CMR exam after 1 week from the MI and after 6 months.

Results

Patients (n=138) were more often men (81%), with a median age of 58 years (interquartile range 48–66). EAT volume was 30 mL/m2 (23–41). Patients with EAT >30 mL/m2 (n=69) were older (60±12 vs. 55±11 years, p=0.02), more often diabetic (26% vs. 12%, p=0.03), and showed a worse baseline risk profile (Thrombolysis in Myocardial Infarction risk score 3 [2–5] vs. 2 [1–4], p=0.05). Patients with EAT >30 mL/m2 also displayed a larger IS (33±15 vs. 23±16% of LV mass, p=0.001) and MVO (1.5 [0–6.8] vs. 0% [0–2.2], p=0.008). Again in patients with EAT >30 mL/m2, EAT volume independently predicted infarct size (standardized beta coefficient=0.30, p<0.001) and MVO area (standardized beta coefficient=0.36, p<0.001) after adjusting for age, sex and infarct characteristics at 1 week (Figure 1). Despite these correlations with infarct size and MVO, patients with EAT >30 mL/m2 did not display more depressed LVEF or larger LV volumes than those with EAT ≤30 mL/m2, either at 1 week or at 6-month CMR (p>0.1 for all comparisons).

Conclusions

In a cohort of patients with first anterior STEMI undergoing timely reperfusion, those with a greater EAT volume have a larger infarct size and a larger area of MVO. Despite these correlates of EAT volume size, patients with larger EAT do not have a higher risk of adverse LV remodelling.

Funding Acknowledgement

Type of funding sources: None.

Infarction of the papillary muscle is an independent predictor of heart failure, ventricular tachycardia, and consequent mortality

Background

Previous studies have assessed the effect of papillary muscle infarction (papMI) as seen with Late Gadolinium Enhancement (LGE) Cardiac Magnetic Resonance imaging (CMR) after ST-segment elevation myocardial infarction (STEMI) on patient prognosis. As these studies delivered inconclusive results due to limited sample size and follow-up, we set out to assess whether STEMI patients with papMI are at an increased risk of cardiovascular mortality, heart failure, and arrhythmic events.

Methods

This is a 3-center observational study in n=1,055 consecutive STEMI patients who underwent CMR at a median of 6 (4–9) days, with a mean follow-up of 6.0 years (IQR 3.1–9.1 years). Any presence of papMI, be it supero-lateral, infero-medial, or double, was evaluated visually on the LGE images and checked on the matched cine images. The primary outcomes are time to cardiovascular mortality, heart-failure events defined as heart failure death and hospital admission for heart failure, and arrhythmic events, defined as arrhythmic death and ventricular tachycardia (VT).

Results

PapMI was diagnosed in 351 patients (33%). PapMI is an independent predictor of cardiovascular mortality after correction for clinically relevant parameters such as infarct size and left ventricular ejection fraction (Multivariate Cox Regression Hazard Ratio (HR)=2.46, 95% confidence interval (CI) 1.23–4.92). Secondly, papMI independently predicts the combined endpoints of heart failure death/heart failure (HR=1.72, 95% CI 1.12–2.63) and arrhythmic death/ VT (HR=4.52, 95% CI 2.18–9.36).

Conclusions

PapMI predicts cardiovascular mortality, arrhythmic death and heart failure. PapMI should be taken into account, especially when conducting new prognosis studies after STEMI and as a stratification factor in studies for secondary prevention of VT and arrhythmic death.

Funding Acknowledgement

Type of funding sources: Other.

Sex-based differences on adverse left ventricular remodeling and clinical outcomes after an ST-segment elevation myocardial infarction in the PCI era

Background

There is conflicting evidence regarding sex-based differences in myocardial salvage and clinical outcome in patients after an ST-segment elevation myocardial infarction (STEMI) in the contemporary era of primary percutaneous coronary intervention (PCI) and optimal medical treatment.

Adverse left ventricular remodelling (LVR) after a STEMI worsens outcomes, however, the influence of sex is not yet clear.

Aim/Purpose

To analyze whether there are sex differences in clinical outcomes and adverse LVR in patients after a STEMI.

Methods

Patients with STEMI who underwent primary PCI were included and a cardiac magnetic resonance (CMR) was performed during hospitalization (6.2±2.6 days) and after 6 months (6.1±1.8 months). LVR, myocardial salvage (MS), infarct size (IS), microvascular obstruction (MVO), and area at risk (AAR) were quantified. Adverse LVR was defined as a 15% increase in LV end-diastolic volume and a relative fall in LV ejection fraction of 3% at 6 months. The primary outcome was a composite of cardiovascular death, admission for heart failure, or ventricular arrhythmia.

Results

A total of 1046 patients were included (mean age: 59.8±9 years; 16.6% women), and a second CMR was completed in 589 patients. Women were older (58.8±8 years vs 65.0±10 years, p<0.0001) and presented more cardiovascular risk factors (Table). The primary outcome occurred in 310 patients during follow-up of 75 months (range: 36–112 months) and was more frequent in women than in men (35.8% vs 22.3%, p<0.001). After adjusting for baseline differences (age, diabetes, hypertension, Killip class, and time to reperfusion), female sex was not an independent predictor of major adverse cardiac events (Fig. 1A & B).

Although adverse LVR was a strong independent predictor for the primary outcome, no interaction was present between sex and LVR (women 6.4% vs men 8%, p=0.46) (Fig 1B), nor did we find significant differences between sex and other CMR derived variables such as MS, IS, MVO and AAR.

Conclusions

After a STEMI, women present worse clinical outcomes than men. However, these differences are related to their clinical characteristics and higher incidence of cardiovascular risk factors, and not to a higher incidence of adverse left ventricular remodeling.

Funding Acknowledgement

Type of funding sources: None.

Impact of persistent MVO late after STEMI on adverse left ventricular remodelling: a CMR study

Background

Despite successful revascularization at the epicardial level, microvascular obstruction (MVO) appears soon after reperfusion in up to 50% of cases. Early MVO has been solidly associated with adverse resulting cardiac structure and heightened risk of future cardiovascular events. Although clinical and experimental studies demostrated the spontaneous repair of MVO, little is known about the occurrence and implications of persistent MVO late after infarction.

Purpose

We used cardiovascular magnetic resonance (CMR) to characterize the impact of persistent MVO late after reperfused ST-segment elevation myocardial infarction (STEMI) on adverse left ventricular (LV) remodelling (ALVR).

Methods

A prospective registry of 471 STEMI patients underwent CMR 7 [5–10] and 198 [167–231] days post infarction, and MVO (>1 segment) and ALVR (relative increase >15% at follow-up CMR) of LV end-diastolic (LVEDVI) and end-systolic volume indices (LVESVI) were determined.

Results

One-week MVO occurred in 209 patients (44%) and persisted in 30 of these (6%). Most patients with persistent MVO (22/30, 73%) displayed extensive (>2.5% of LV mass) MVO at 1 week. Compared with patients without MVO (n=262, 56%) or with MVO only at 1 week (n=179, 38%), those with persistent MVO at follow-up (n=30, 6%) showed higher rates of ALVR-LVEDVI (22%, 27%, 50% p=0.003) and ALVR-LVESVI (20%, 21%, 53% p<0.001). After adjustment, the extent (% of LV mass) of MVO at follow-up was independently associated with ΔLVEDVI (relative increase, %) (p=0.01) and ΔLVESVI (p=0.03). Compared to a 1:1 matched population of 30 patients with MVO only at 1 week, patients with persistent MVO more frequently displayed ALVR-LVEDVI (12% vs. 50%, p=0.003) and ALVR-LVESVI (12% vs. 53%, p=0.001).

Conclusion

MVO persists in a small percentage of patients in chronic phase after STEMI and exerts deleterious effects in terms of LV remodelling. These findings fuel the need for further research on microvascular injury repair.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER” [grant numbers PI20/00637, PI15/00531, FI18/00320, and CIBERCV16/11/00486] and by Conselleria de Educaciόn – Generalitat Valenciana (PROMETEO/2021/008).

Deleterious effect of serum from stemi patients on endothelial cell viability: implication on the resulting cardiac structure

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER” (grant numbers PI20/00637 and CIBERCV16/11/00486) and Conselleria de Educación – Generalitat Valenciana (PROMETEO/2021/008).

Aim

To evaluate the potential deleterious effect of serum from STEMI patients on cardiovascular magnetic resonance (CMR)-derived edema, hemorrhage and microvascular obstruction as well as on the grade of permeability in vitro by promoting endothelial cell apoptosis and necrosis in vitro.

Methods

Human coronary artery endothelial cells (HCAEC) were incubated with serum isolated 24h post-reperfusion from 43 STEMI patients submitted to CMR and from 10 control subjects. Using a multidisciplinary approach on HCAEC, the effect of serum from STEMI patients on the activation of apoptosis and necrosis as well as on changing the permeability and structure of the endothelial monolayer was assessed. The association between the serum-induced apoptosis and necrosis in vitro on HCAEC and CMR-derived edema, hemorrhage, and microvascular obstruction as well as the grade of permeability in vitro was also dissected.

Results

Serum from STEMI patients activated apoptosis (p<0.01) and necrosis (p<0.05) in HCAEC, evaluated by flow cytometry, enzymatic, genetic, and morphological analysis, and also provoked an increased in the permeability of the endothelial monolayer in vitro (p<0.01), due to enlarged intercellular spaces (p<0.05). Those patients whose serum induced higher necrosis in vitro displayed extensive CMR-derived edema (p<0.01), hemorrhage (p<0.01), and microvascular obstruction (p<0.05) as well as more endothelial permeability in vitro (p<0.05).

Conclusions

By activating apoptosis and necrosis on endothelial cells, serum from STEMI patients participates in the appearance of edema, hemorrhage, and microvascular obstruction as well as in increasing endothelium permeability. The negative effect of serum on the endothelial barrier can contribute to the adverse cardiac structure post-STEMI.

Temporal and spatial dynamics in the regulation of myocardial metabolism during the ischemia-reperfusion process

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work was supported by “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER” (grant numbers PI20/00637 and CIBERCV16/11/00486) and Conselleria de Educación – Generalitat Valenciana (PROMETEO/2021/008).

Introduction

In the context of severe myocardial ischemia, cardiac metabolism shifts from beta oxidation to glycolisis. However, the temporal and spatial dynamics of the main regulators of myocardial metabolism during the ischemia-reperfusion process in the infarcted heart has not been fully characterized.

Methods

Myocardial infarction (MI) was induced in swine by means of 90 minutes occlusion of the mid left anterior descending coronary artery using angioplasty balloons. Tetrazolium staining and intracoronary infusion of thioflavin-S were used to define the infarcted, adjacent, and remote areas. mRNA and protein expression of PGC1a, PPARa, ERRa, GLUT1, and GLUT4 were quantified in controls and in MI groups submitted to 48 hours and 3 weeks of reperfusion.

Results

Compared to controls, a severe and generalized drop of PGC1a mRNA gene and protein levels occurred in the infarcted, adjacent and remote areas since ischemia onset until 48 hours reperfusion that persists at 1 month in the infarcted region. Similar dynamics occurred in the infarcted, adjacent, and remote areas in the case of PPARa gene expresion; PPARa protein significantly decreased only until 48 hours reperfusion in the infarcted area. ERRa gene and protein expression persistenly decreased only in the infarcted region since ischemia onset until 1 month. Incrases in GLUT1 (since ischemia onset) and GLUT4 (at 1 month) were detected.

Conclusions

Dynamics and generalized changes in metabolism regulation to a shift from beta oxidation to glycolisis occur in the infarcted heart since ischemia onset until late after reperfusion. Further research in this field can be helpful for a better understanding of pathophysiology of myocardial infarction and to explore new therapeutic options.

Implication of caveolae in the pathophysiology of human acute myocardial infarction: a histological study

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This work has been funded by “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER” (Exp. PI20/00637) as well as by “Generalitat Valenciana” (Exp. PROMETEO/2021/008).

Introduction

Caveolae are lipid invaginations present in the membrane of most mammalian cells. They are mainly made up of three proteins: caveolin (Cav)-1, 2, and 3 and are involved in signal transduction and ion channels. Since caveolae regulate different signalling pathways to promote cardiac protection, the aim of this study is to compare the expression of Cav-1, 2, and 3 in the human myocardium of control subjects and in patients with myocardial infarction (MI).

Materials

Myocardial samples from human autopsies of 4 controls and 4 MI patients with more than 6 months of evolution were isolated. The infarction and control area were identified by haematoxylin-eosin and Masson’s trichromic stainings. The presence of Cav-1, 2 and 3 was detected by immunochemistry. Afterwards, 5 photographs were taken for each antibody and sample and the presence of each protein was morphometrically quantified using the image analyzer Image-Pro Plus. These results were also corroborated by immunofluorescence.

Results

A constitutive presence of Cav-1, 2, and 3 was observed in the myocardium of control patients, being Cav-1 and 3 higher expressed than Cav-2. Cav-2 and 3 were mainly found in cardiomyocytes, while Cav-1 was detected not only in cardiac muscle cells but also in endothelial cells. Comparing caveolae expression between the peri-infarct region of MI patients and controls, a significant reduction in the expression of the three proteins was observed by immunochemistry. Indeed, the decrease in Cav-2 and 3 could be also detected by immunofluorescence. Lastly, Cav-1 was more expressed in cardiomyocytes than in endothelial cells, but unlike muscle cells, its expression was not diminished after MI.

Conclusions

The presence of caveolin decreases in the myocardial tissue after MI. Further studies are needed to confirm the cardioprotective role of caveolae post-AMI and their use as potential therapeutic target.

Overexpression of genes involved in lymphocyte activation and regulation are associated with reduced CRM-derived cardiac remodelling after STEMI

Aims

Lymphopenia after ST-segment elevation myocardial infarction (STEMI) correlates with deleterious cardiac consequences and worse prognosis. An in-depth examination of genes implicated in lymphocyte proliferation, activation and regulation and their association with short- and long-term cardiac structure and function is therefore of great interest.

Methods

Peripheral blood mononuclear cells were isolated from 10 control subjects and 64 patients with a first STEMI treated with primary percutaneous coronary intervention and submitted to cardiac magnetic resonance after 1 week and 6 months. mRNA expression of genes implicated in lymphocyte activation (CD25 and CD69) and regulation [programmed death (PD)-1 and cytotoxic T-lymphocyte antigen (CTLA)-4] were determined by qRT-PCR.

Results

In comparison to controls, STEMI patients showed heightened mRNA expression of CD25 and lower PD-1 and CTLA-4 96h after coronary reperfusion. Patients with extensive infarctions (>30% of left ventricular mass) at 1 week displayed a notable reduction in CD25, CD69, PD-1, and CTLA-4 expression (p<0.05). However, CD25 was the only predictor of 1-week extensive infarct size in multivariate logistic regression analysis (odds ratio 0.019; 95% confidence interval [0.001–0.505]; p=0.018). Regarding long-term ventricular function, mRNA expression of CD25 under the mean value was associated with worse ventricular function and more adverse remodelling.

Conclusions

Following STEMI, heightened expression of genes expressed in regulatory T cells (CD25 and CD69) and immune checkpoints (PD-1 and CTLA-4) correlates with a better short- and long-term cardiac structure and function. Advancing understanding of the pathophysiology of lymphopenia and evaluating novel immunomodulatory therapies will help translate these results into future clinical trials.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER”

Downstream testing after exercise ECG stress test – can we predict ischemia on subsequent vasodilator stress cardiac magnetic resonance?

Background

Exercise ECG stress test (ExECG) is useful in the diagnostic work-up of patients with chest pain and known or suspected stable ischemic heart disease (SIHD). However, current guidelines recommend a stress imaging, ischemia-detecting technique such as vasodilator stress cardiac magnetic resonance (vs-CMR) if available. Whether clinical and ExECG variables can predict ischemia on subsequent vs-CMR testing is unknown.

Material and methods

We retrospectively included 289 patients who underwent an ExECG and a subsequent vs-CMR in the year after this test and who didn't undergo a revascularization procedure in this time frame. Clinical, ExECG and vs-CMR variables were included in the registry. vs-CMR was considered positive if ischemia was evident in at least one myocardial segment on stress first-pass perfusion without concomitant necrosis on late gadolinium enhancement imaging. We performed univariate and multivariate analysis to check for the association of variables with the risk of ischemia on vs-CMR.

Results

Mean time from ExECG to vs-CMR was 97,27±88,31 days and 91 vs-CMR were positive for ischemia. Age, male sex, diabetes mellitus, hypertension, dyslipidaemia and personal history of ischemic heart disease, percutaneous coronary intervention (PCI) or coronary artery bypass grafting (CABG) were predictors of ischemia on vs-CMR in the univariate analysis. On ExECG, time of exercise, exercise capacity, chest pain during ExECG, maximum heart rate (HR) and systolic blood pressure (SBP), % of predicted HR, chronotropic reserve index, maximum and reserve of double product and Duke Treadmill Score were also associated with ischemia on vs-CMR. However, the only independent predictors on multivariate binary logistic regression stepwise analysis were history of PCI (HR 3.79 [2.03–7.09], p<0.001) or CABG (HR 5.57 [1.80–17.26], p=0.003), maximum double product (HR 0.94 [0.90–0.99] per 1000 increase, p=0.02) and Duke Treadmill Score (HR 0.95 [0.91–0.99], p=0.019). Subgroup analysis showed that male sex (HR 1.95 [1.16–3.28], p=0.012), history of ischemic heart disease (HR 4.73 [2.88–7.76], p<0.001) and maximum double product (HR 0.94 [0.90–0.98] per 1000 increase, p=0.006) were predictors of ischemia on vs-CMR in non-revascularized patients (n=212). In revascularized patients (n=77) the only independent predictor was the Duke Treadmill Score on ExECG (HR 0.93 [0.86–0.99], p=0.048).

Conclusions

Several ExECG variables, namely Duke Treadmill Score and parameters of myocardial oxygen consumption such as maximum doble product, can predict the risk of ischemia on subsequent vs-CMR in revascularized and non-revascularized patients with chest pain. This can help select patients who should undergo vs-CMR afeter ExECG for ischemia detection.

Funding Acknowledgement

Type of funding sources: None.

Exercise ECG testing in patients without known ischemic heart disease: predictors of ischemia of downstream vasodilator stress cardiac magnetic resonance

Background

In routine clinical practice, patients with chest pain and suspected stable ischemic heart disease (SIHD) usually undergo an exercise ECG stress test (ExECG) for ischemia detection. However, since the sensitivity of this technique is relatively low, concerns exist that many patients could remain underdiagnosed. We intend to assess the clinical and ExECG predictors of ischemia on subsequent vasodilator stress cardiac magnetic resonance (vs-CMR) to help select which patients should undergo downstream testing after an initial ExECG.

Material and methods

We retrospectively included 197 patients without previous history of ischemic heart disease who underwent an ExECG and a subsequent vs-CMR in the year after this test and who didn't undergo a revascularization procedure in this time frame. Clinical, ExECG and vs-CMR variables were included in the registry. vs-CMR was considered positive if ischemia was evident in at least one myocardial segment on stress first-pass perfusion without concomitant necrosis on late gadolinium enhancement imaging. We performed univariate and multivariate analysis to check for the association of variables with the risk of ischemia on vs-CMR.

Results

Mean time from ExECG to vs-CMR was 88.69±84.32 days and 37 vs-CMR were positive for ischemia. Male sex, less exercise time, less % of maximum predicted exercise capacity, less maximum double product (heart rate x systolic blood pressure) and less double product reserve (DPR = maximum double product - basal double product) were associated with ischemia on vs-CMR on univariate analyses. However, the only independent predictors of ischemia on vs-CMR on multivariate binary logistic regression were male sex (HR 2.62 [CI 95%: 1.13–5.76], p=0.016) and less DPR (HR 0.90 [CI 95%: 0.84–0.97] per 1000 increase, p=0.006). The risk score derived from these two variables had a moderate predictive power (ROC curves, AUC 0.657, p=0.003). The best cut-off point for the DPR was 12400, as derived from the Youden index. It allowed stratification of the risk of ischemia on vs-CMR, which ranged from 9% in women with >12400 DPR, 18.8% in men with >12400 DPR, 24.1% in women with ≤12400 DPR to 42.9% in men with ≤12400 DPR (p=0.005, Figure 1).

Conclusions

Male sex and less double product reserve on ExECG can moderately predict the risk of ischemia on subsequent vs-CMR in patients presenting with chest pain and without previous SIHD. This can help select patients who benefit most from vs-CMR for diagnostic purposes.

Funding Acknowledgement

Type of funding sources: None. Figure 1

Residual ST-segment elevation at pre-discharge ECG after STEMI: association with long-term prognosis and structural consequences at 6-month CMR

Introduction

Residual ST-segment elevation after ST-segment elevation myocardial infarction (STEMI) has been traditionally interpreted as a predictor of left ventricular dysfunction and ventricular aneurism. More recently, it has also been associated with more severe structural consequences in cardiac magnetic resonance (CMR) performed soon after STEMI. However, the implications in terms of long-term prognosis of patients and structural consequences in CMR performed late after STEMI are unclear.

Methods

Data was obtained from a prospective registry of reperfused STEMI patients. At pre-discharge ECG, sum and maximum ST-segment elevation (mm), ST-segment resolution (%) and the number of Q-leads with residual ST-segment elevation >1 mm (Q-STE) were assessed. 6-month CMR parameters were quantified: left ventricular ejection fraction (LVEF, %), left ventricular end-diastolic and end-systolic volume indexes (LVEDVI and LVESVI, mL/m2), infarct size (IS, % left ventricular mass) and microvascular obstruction (MVO, % left ventricular mass). The primary end-point was major adverse cardiac events (MACE), defined as all-cause death and/or re-admission for acute heart failure, whichever occurred first.

Results

488 patients were included. Mean age was 58±12 years, 80.3% were males and smoking was the most prevalent cardiovascular risk factor. During a 7-year mean and median follow-up, 92 MACE were registered (19%), 39 all-cause deaths and 53 re-admission for acute heart failure. Q-STE >1 lead was detected in 172 patients (35%) and it was the most potent ECG predictor of MACE (26% vs 15%, p=0.002). Q-STE was also associated with structural changes at 6-month CMR: larger LVEDVI (87,39±27,47 mL/m2 vs 74,31±24,13 mL/m2) and LVESVI (45,45±25,24 mL/m2 vs 32,53±20,85 mL/m2), less LVEF (50,48±13,95% vs 58,75±12,3%) and larger infarct size (24,91±11,6% vs 14,38±11,41%) (p<0.001 for all comparisons, Figure 1). After adjustment for baseline and ECG characteristics, Q-STE (per lead with >1 mm) was independently associated with a higher risk of long-term MACE (HR 1.24 [CI 95%: 1.09–1.40], p=0.001), depressed (<40%) LVEF (HR 1.26 [CI 95%: 1.02–1.56], p=0.03) and large (>30% left ventricular mass) infarct size (HR 1.34 [CI 95%: 1.08–1.67], p=0.008) at 6-month CMR. Survival free from MACE was lower in patients with >1 lead Q-STE (log-rank=9.07, p=0.003) (Figure 2).

Conclusions

Residual ST-segment elevation after STEMI represents a widely available predictor of adverse long-term prognosis and late CMR-derived left ventricular remodelling. It could contribute to select patients who would benefit of close monitoring.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Fondos Europeos de Desarrollo Regional FEDERInstituto de Salud Carlos III Figure 1. Structural changes at 6-month CMRFigure 2. Survival free from MACE

Stress cardiovascular magnetic resonance and mortality in a registry of 2496 elderly patients with chronic coronary syndrome. Prognosis and decision-making

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Instituto de Salud Carlos III, Fondo Europeo de Desarrollo Regional (FEDER)

Introduction and objectives. Management of the elderly with chronic coronary syndrome (CCS) is challenging. We explore the prognostic value and the usefulness for decision-making of the ischemic burden determined by vasodilator stress cardiac magnetic resonance (CMR) imaging in elderly patients with known or suspected CCS.

Methods. The study group was made up of 2496 patients older than 70 years submitted to vasodilator stress CMR for known or suspected CCS. The ischemic burden (number of segments with stress-induced perfusion deficit) was calculated following the 17-segment model. Its association with all-cause mortality and the effect of CMR-guided revascularization were analyzed retrospectively.

Results. During a median follow-up of 4.58 years, 430 deaths (17.2%) were recorded. A larger ischemic burden was an independent predictor of mortality: hazard ratio [95% confidence intervals]: 1.04 [1.01-1.07] for each additional ischemic segment, p = 0.006). This association also occurred in patients over 80 years of age and in women (p < 0.001). Compared to non-revascularized patients, revascularization associated with worse outcomes at low ischemic burden and exerted protective prognostic effect in patients with extensive ischemia both in the whole group (p for interaction = 0.003) and in 496 patients matched 1:1 by a propensity score (p = 0.06).

Conclusions. Vasodilator stress CMR represents a valuable tool to stratify risk in elderly patients with CCS and might be helpful to guide decision-making in this scenario.

Sequential cardiovascular magnetic resonance assessment of left ventricular ejection fraction for prediction of subsequent events in a large multicenter STEMI registry

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): This work was supported by “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER”

Background. Cardiovascular magnetic resonance (CMR) is the best tool for left ventricular ejection fraction (LVEF) quantification, but as yet the prognostic value of sequential LVEF assessment for major adverse cardiac event (MACE) prediction after ST-segment elevation myocardial infarction (STEMI) is uncertain.

Purpose. We explored the prognostic impact of sequential assessment of CMR-derived LVEF after STEMI to predict subsequent MACE.

Methods. We recruited 1036 STEMI patients in a large multicenter registry. LVEF (reduced [r]: <40%; mid-range [mr]: 40-49%; preserved [p]: ≥50%) was sequentially quantified by CMR at 1 week and after >3 months of follow-up. MACE was regarded as cardiovascular death or re-admission for acute heart failure after follow-up CMR.

Results. During a 5.7-year mean follow-up, 82 MACE (8%) were registered. The MACE rate was higher only in patients with LVEF < 40% at follow-up CMR (r-LVEF 22%, mr-LVEF 7%, p-LVEF 6%; p-value < 0.001). Based on LVEF dynamics from 1-week to follow-up CMR, incidence of MACE was 5% for sustained LVEF³40% (n = 783), 13% for improved LVEF (from <40 to ³40%, n = 96), 21% for worsened LVEF (from ³40% to <40%, n = 34) and 22% for sustained LVEF <40% (n = 100), p-value < 0.001. Using a Markov approach that considered all studies performed, transitions towards improved LVEF predominated and only r-LVEF (at any time assessed) was significantly related to higher incidence of subsequent MACE.

Conclusions. LVEF constitutes a pivotal CMR index for simple and dynamic post-STEMI risk stratification. Detection of reduced LVEF (<40%) by CMR at any time during follow-up identifies a small subset of patients at high risk of subsequent events.

Stress cardiovascular magnetic resonance and mortality in a registry of 2496 elderly patients with chronic coronary syndrome. Prognosis and decision-making

Funding Acknowledgements

Type of funding sources: None.

Background. In recent guidelines, non-invasive imaging techniques play a pivotal role in the management of chronic coronary syndrome (CCS). The elderly represent a large percentage of our routine CCS population and risk stratification in this scenario is challenging. The potential of vasodilator stress cardiovascular magnetic resonance (CMR) for this purpose is unknown.

Purpose. We explore the prognostic value and the usefulness for decision-making of the ischemic burden determined by vasodilator stress CMR imaging in a large cohort of elderly patients with known or suspected CCS.

Methods. The study group was made up of 2496 patients older than 70 years submitted to vasodilator stress CMR for known or suspected CCS in our health department from 2001 to 2016 (mean age 76 ± 4 years, 52% male). Clinical and vasodilator stress CMR characteristics were prospectively recorded. The ischemic burden (number of segments with stress-induced perfusion deficit) was calculated following the 17-segment model. Its association with all-cause mortality and the effect of vasodilator stress CMR-guided revascularization (within the following 3 months) were analyzed retrospectively.

Results. During a median follow-up of 4.58 years, 430 deaths (17.2%) were recorded. A larger ischemic burden was an independent predictor of mortality: hazard ratio [95% confidence intervals]: 1.04 [1.01-1.07] for each additional ischemic segment, p = 0.006). This association also occurred in patients over 80 years of age and in women (p < 0.001). Compared to non-revascularized patients, revascularization associated with worse outcomes at low ischemic burden and exerted protective prognostic effect in patients with extensive ischemia both in the whole group (p for interaction = 0.003) and in 496 patients matched 1:1 by a propensity score (p = 0.06).

Conclusions. Vasodilator stress CMR represents a valuable tool to stratify risk in elderly patients with known or suspected CCS and might be helpful to guide decision-making in this scenario.

Abstract Figure 1

Prognostic value of vasodilator stress CMR in elderly patients with known or suspected chronic coronary syndrome

Background

In recent guidelines, non-invasive imaging techniques play a pivotal role in the management of chronic coronary syndrome (CCS). The elderly represent a large percentage of our routine CCS population and risk stratification in this scenario is challenging. The potential of vasodilator stress cardiovascular magnetic resonance (vs-CMR) for this purpose is unknown.

Purpose

We explored the prognostic value of the ischemic burden, as derived from vs-CMR, in elderly patients with known or suspected CCS.

Methods

From the general cohort of 6389 patients with known or suspected CCS submitted to undergo vs-CMR in our health department from 2001 to 2016, we performed a subanalysis of the 1225 patients >70 year-old (mean age 77±5 years, 51% male). Clinical and vs-CMR characteristics were prospectively recorded. The ischemic burden (at stress first-pass perfusion imaging) was computed (using the 17-segment model). The occurrence of major adverse cardiac events (MACE) defined as all-cause death and/or non-fatal myocardial infarction (whichever occurred first) was retrospectively revised using the electronic regional health system registry.

Results

During a median follow-up of 2.7 years, 203 MACEs were registered (17%). Age (77±4 vs. 76±5 years) was not significantly different in patients with and without MACE. Larger left ventricular (LV) end-diastolic and end-systolic volume indexes, more depressed LV ejection fraction, more extensive areas with late gadolinium enhancement and ischemic burden were detected in patients with MACE (p<0.001 for all comparisons). In non-revascularized patients (n=1118), the MACE rate ranged from 13% (in patients with 0–1 ischemic segments) to 35% (in those with >8 ischemic segments, p<0.001 for the trend). In the small subset of revascularized patients (n=107), revascularization exerted a non-significant protective effect only in patients with extensive ischemic burden (>5 segments).

Conclusions

Vasodilator stress CMR represents a valuable tool to stratify risk in elderly patients with known or suspected CCS and might be helpful to guide decision-making.

Figure 1

Funding Acknowledgement

Type of funding source: None

Echocardiographic strict negative criteria for suspected infective endocarditis. Can we avoid unnecessary echocardiograms?

Background

Infective endocarditis (IE) is an uncommon but potentially lethal disease that require a timely diagnosis. Transthoracic echocardiography (TTE) has a pivotal role in diagnosis and follow-up and should be requested if there is a clinical suspicion of IE. However, it is unclear which patients can benefit from a follow-up echocardiogram if the initial TTE shows no signs of IE. The strict negative criteria (SNC) have been recently proposed to avoid unnecessary follow-up echocardiograms.

Purpose

The objective of this study is to review the contemporary, real-world use of echocardiography in patients with suspected IE and analyze the possible effect that incorporating the SNC would have in our clinical practice.

Methods

We searched the echocardiography database for the words “endoc” and “veget” to find the tests that were performed for suspected or confirmed IE between January 2014 and December 2018. We extracted and manually reviewed all the echocardiographic data and applied the SNC to patients with an initial negative TTE. We reviewed the electronic clinical history to check if a final diagnosis of IE was established or not.

Results

We included a total of 957 echocardiograms in our registry. 493 (51.5%) did not meet the SNC. The main reasons for exclusion were the occurrence of more than mild valvular regurgitation (n=293, 30.6%), the presence of typical or suggestive signs of IE (n=128, 13.3%), the evidence of more than mild valvular stenosis or sclerosis (n=105, 10.9%) and a suboptimal ultrasound quality (n=90, 9.4%). Globally, a follow-up echocardiogram was performed in 143 (14.9%) patients. Only in 25 (5.4%) of patients which fulfilled the SNC a follow-up echocardiogram was requested, compared to 60 (16%) patients which neither fulfilled the SNC nor showed echocardiographic signs of IE and 68 (53.5%) patients in which the SNC weren't met but showed echocardiographic signs of IE (p<0.001). After performing a binary logistic regression model, the only independent predictor of follow-up echocardiography in patients who didn't met the SNC was the presence of typical or suggestive signs of infective endocarditis on initial TTE (HR 2.84 [2.17–3.71], p<0.001).

Conclusions

1. In a real-life, observational setting an initial TTE for suspected IE that fulfilled the defined SNC predicts a low probability of requesting a follow-up echocardiography (5.4%), even though these criteria were neither reported by the echocardiographist nor probably known by the clinician in charge of the patient.

2. The number of echocardiograms avoided by applying these criteria in this context is low.

3. A follow-up echocardiogram was requested more frequently if the SNC weren't met, especially when typical or suggestive signs of IE were described in the initial TTE (53.5% vs 16%). This factor seems to be the only independent echocardiographic variable that predicts the probability of requesting a follow-up echocardiogram in this subgroup of patients.

Figure 1

Funding Acknowledgement

Type of funding source: None

P863Morphometric analysis of the dynamic changes of the interstitium after reperfused myocardial infarction

Background

The interstitial space is mainly composed by cells, fibers and gels of polysaccharides, which act as a compression buffer against the stress placed on the extracellular matrix (ECM). After myocardial infarction (MI), heart has to withstand higher mechanical stress due to injured cardiomyocytes. ECM composition notably influences the mechanical properties of the myocardium and participates in left ventricular remodeling.

Purpose

To characterize the myocardial ECM changes from ischemia onset until late phases after coronary reperfusion in a swine model of reperfused MI.

Methods

MI was induced in swine by transient 90-min coronary occlusion using angioplasty balloons. One control group and three MI groups were defined: 1) without reperfusion, 2) 1-week, and 3) 1-month reperfusion (n=5, each). Myocardial samples from the infarcted area were isolated and histologically staining to evaluate the presence of collagen type I, collagen type III, elastic fibers, and proteinglycans. Moreover, the presence of laminin, fibronectin, and secreted protein, acidic and rich in cysteine (SPARC) was determined by immunohistochemistry. Five independent photographs for each group and each stain were taken and the presence of the different components of the interstitium was morphometrically quantified. Indeed, the mRNA levels of metalloproteinases (MMP), tissue inhibitors of metalloproteinases (TIMP), and transcription factors implicated in ECM remodeling were quantified.

Results

In the no-reperfusion group, an increase in fibronectin, laminin, and elastic fibers were observed, whereas no changes neither in the quantity nor in the organization of collagen-I and collagen-III fibers were detected. In the 1-week and 1-month reperfusion groups, an augmentation in the content of collagen-I, collagen-III, elastic fibers were found. These fibers displayed a more organized pattern compared to control tissue. The quantity of proteinglycans, laminin, fibronectin, and SPARC were also increased. These changes could be explained by a heightening in the mRNA expression of TIMP1, TIMP2, and TIMP3 from the ischemic period until chronic phases, whereas no changes were observed for TIMP4. MMP2 and MMP9 mRNA levels were boosted in late phases post-MI. When exploring the mRNA levels of transcription factors implicated in ECM remodeling, CTGF increased during the ischemic period, whereas TNF-α and TGF-β augmented after 1-week and 1-month post-reperfusion, respectively.

Conclusions

ECM remodeling starts after ischemia onset, probably aiming to protect cardiomyocytes from the ischemic damage. After reperfusion, the ECM evolves to constitute a fibrotic scar to maintain a proper cardiac function. These changes may be orchestrated by the fluctuation in genes specially implicated in ECM distribution. ECM changes might be accurately regulated since it could provoke an adverse left ventricular remodelling, consequently impairing patient prognosis.

Acknowledgement/Funding

This study was funded by “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER” (PIE15/00013, PI17/01836, and CIBERCV16/11

P864Histopathological damages in the epicardial coronary artery after ischemia and reperfusion injury in swine

Background

The microscopic consequences in the myocardial capillaries after myocardial infarction (MI) have been widely addressed, but little attention has been paid to epicardial coronary arteries. Since epicardial circulation is responsible for providing blood flow to the heart, understanding the microscopical changes on the epicardial artery after MI becomes also crucial.

Purpose

To evaluate the dynamics of the microscopic damages in the coronary arteries post-MI in swine model of reperfused MI.

Methods

MI was induced in swine by transient 90-min coronary occlusion of the left anterior descending (LAD) coronary artery using angioplasty balloons. One control group and four MI groups were defined: 1) without reperfusion, and 2) 1-min, 3) 1-week, and 4) 1-month reperfusion (n=3, each). In each group, LAD (infarct-related artery) and the right coronary artery (RCA) were isolated. Taking as reference the region in which balloon was inflated, we also separated samples from two different regions: proximal and distal LAD. Histological stainings (HE, Masson's trichromic, and orcein) and immunohistochemistry against CD31 (endothelial cells), a-smooth muscle cells, and CD45 (total leukocytes) were performed.

Results

Abnormalities in the endothelial monolayer of the LAD artery started even before reperfusion (during ischemia). This damage dramatically increased after reperfusion, observing an almost absence of CD31+ cells in the tunica intima and some breaks in the internal elastic layer from the 1-min and 1-week reperfusion groups. No irregularities were found in the tunica media from the no reperfusion group, whereas an increased in its thickness was detected soon after reperfusion. In the 1-week reperfusion group, larger thickness, a desorganized muscular cells distribution, and oedema were found. The damage in the tunica intima and media was more pronounced in the region distal to the angioplasty balloon compared to the proximal region, whereas no changes were detected in the RCA. In the tunica adventitia, vasa vasorum density was reduced during the ischemic phase, remaining low in the 1-min and 1-week reperfusion group, while being restored after 1-month reperfusion. This dynamics was similar in both LAD regions, while no changes in the RCA were found. After coronary reperfusion, a higher leukocyte adhesion to the endothelium from the LAD artery, mainly in the region proximal to the balloon inflation, was observed. The process evolves, resulting in a massive presence of CD45+ cells not only in the tunica intima, but also in the media and the adventitia monolayer isolated from the 1-week reperfusion group.

Conclusions

The microscopic structure of the infarct-related coronary artery was compromised after MI. This damage started during ischemia and boosted after reperfusion, becoming more pronounced in the region distal to balloon inflation. Exploring these damages will be important for a better understanding of the pathophysiology of MI.

Acknowledgement/Funding

This study was funded by “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER” (PIE15/00013, PI17/01836, and CIBERCV16/11

P6397Ejection fraction by cardiac magnetic resonance 6 months after STEMI: impact on risk stratification in chronic phase

Background

Left ventricular ejection fraction (LVEF) has traditionally been used as the cornerstone for risk stratification after STEMI and it can be accurately quantified by cine cardiovascular magnetic resonance (CMR). In recent years, the additional prognostic value of contrast CMR-derived infarct size (IS) and microvascular obstruction (MVO) soon after infarction has been demonstrated. The usefulness of CMR-derived LVEF in chronic phase for risk stratification late after STEMI is unclear.

Purpose

We hypothesized that 6-month CMR-derived LVEF can contribute in the prediction of clinical events late after STEMI beyond pre-discharge LVEF, IS and MVO.

Methods

Data were obtained from a prospective registry of reperfused STEMI patients (n=456) who were stable 6 months after infarction and in whom 1-week and 6-month CMR-derived LVEF, IS and MVO were sequentially quantified. Major adverse cardiac events (MACE) were defined as a combined clinical end-point that included death or re-admission for acute decompensated heart failure (r-ADHF), whichever occurred first, occurring after the 6-month CMR.

Results

During a mean and median follow-up of 6 years, 56 late MACE (12%, 32 deaths and 24 r-ADHF) were registered. From 1-week to 6-month, CMR parameters exhibited significant dynamic changes (p<0.001): LVEF improved (52±12 vs. 56±13%), IS decreased (21±14 vs. 18±12% of LV mass) and MVO vanished (2±4 vs. 0±1% of LV mass). At 6-month CMR, 60 patients (13%) displayed reduced LVEF (<40%), 69 (15%) mid-range LVEF (40–50%) and 327 (72%) preserved LVEF (≥50%). Late MACE rates were 28% in patients with reduced LVEF, 14% in those with mid-range LVEF and 9% in those with preserved LVEF at 6-month CMR (p<0.001 for the trend). After adjustment for baseline characteristics and for 1-week and 6-month CMR parameters, more preserved LVEF at 6 months independently associated with a lower risk of MACE late after STEMI (hazard ratio 0.96 [0.94–0.98] per 1% increase).

Conclusions

Dramatic dynamic changes occur in CMR parameters within the first months after STEMI. Reassessment of CMR-derived LVEF in chronic phase in those patients who remain stable provides relevant prognostic information for long-term risk stratification.

Acknowledgement/Funding

Funded by “Instituto de Salud Carlos III”/FEDER (PIE15/00013, PI17/01836, and CIBERCV16/11/00486 grants) and Generalitat Valenciana (GV/2018/116).