Prognostic value of cardiac magnetic resonance in elderly patients soon after ST-segment elevation myocardial infarction

Background

Elderly patients with ST-segment elevation myocardial infarction (STEMI) represent a very high-risk population. Data on the prognostic value of cardiac magnetic resonance (CMR) in this scenario are scarce.

Purpose

We aim to study the prognostic value of an early (1-week) CMR in elderly patients after STEMI and to create a simple risk score including clinical and CMR variables.

Methods

The registry comprised 247 patients over 70 years of age discharged for a first STEMI treated with percutaneous intervention and included in a multicenter registry. Baseline characteristics, echocardiographic parameters and CMR-derived left ventricular ejection fraction (LVEF, %), infarct size (% of left ventricular mass) and microvascular obstruction (MVO, number of segments) were prospectively collected. The additional prognostic power of CMR was assessed using adjusted C-statistic, net reclassification index (NRI) and integrated discrimination improvement index (IDI).

Results

During a 4.8-year mean follow-up, 66 (26.7%) first major adverse cardiac events (MACE) occurred (27 all-cause deaths and 39 re-admissions for acute heart failure). Higher GRACE score (HR 1.03 [1.02–1.04], p<0.001), more depressed CMR-LVEF (HR 0.97 [0.95–0.99] per increased %, p=0.006) and more extensive MVO (HR 1.24 [1.09–1.4] per segment, p=0.001) predicted MACE occurrence. The addition of CMR data significantly improved MACE prediction compared to the model with baseline and echocardiographic characteristics (C-statistic 0.759 [0.694–0.824] vs. 0.685 [0.613–0.756], NRI=0.6, IDI=0.08, p<0.001). The best cut-offs for independent variables were GRACE score >155, LVEF <40%, and MVO ≥2 segments. A simple score (0, 1, 2, and 3) based on the number of altered factors accurately predicted the MACE per 100 person-years: 0.78, 5.53, 11.51 and 78.79, respectively (p<0.001).

Conclusions

CMR data contribute valuable prognostic information in elderly patients submitted to undergo CMR soon after STEMI.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Instituto de Salud Carlos III and “Fondos Europeos de Desarrollo Regional FEDER” and Conselleria de Educaciόn – Generalitat Valenciana.

Cardiac magnetic resonance characterization and prediction of left ventricular thrombus after ST-segment elevation myocardial infarction

Background

Left ventricular thrombus (LVTh) is an uncommon yet serious complication after ST-segment elevation myocardial infarction (STEMI). Late gadolinium enhancement (LGE) sequences in cardiac magnetic resonance (CMR) imaging allows for accurate detection of LVTh. However, the implications of CMR to predict and characterize LVTh occurrence is this population is unclear.

Purpose

We aim to characterize the incidence, outcomes, and predictors of LVTh after STEMI by CMR imaging.

Methods

Our registry comprised 455 patients admitted for a first reperfused STEMI in our university hospital. Baseline characteristics were recorded. All patients underwent early (1-week) and late (6-month) CMR. Left ventricular ejection fraction (LVEF, %), infarct size (% of left ventricular mass) and microvascular obstruction (MVO, number of segments) were measured. LGE sequences were used to analyze the presence of LVTh. Patients with LVTh at 6-month CMR underwent an additional CMR 1 year after admission. Univariate and multivariate comparisons were performed to study the ocurrence of LVTh in the first 6 months after STEMI.

Results

Mean age was 58.24±11.69 years, most patients were male (82.6%) and anterior infarction occurred in more than half of the cohort (52.7%). LVTh was detected in 36 (7.9%) patients in the first 6 months after STEMI. Anticoagulation was initiated in all cases. Of these, 27 patients had LVTh at early (1-week) CMR, but 9 had LVTh at late (6-month) CMR with no prior evidence of LVTh at early CMR. A total of 6 patients had persisting LVTh at 1-year CMR (37.5% of patients with 6-month LVTh). In multivariable analysis, anterior infarction (HR 6.6 [1.91–22.83], p<0.001) and 1-week CMR-LVEF (HR 0.97 [0.93–0.99], p=0.04) and MVO (HR 1.19 [1.02–1.39], p=0.03) independently predicted the occurrence of LVTh in the first 6 months after STEMI. We computed a risk score of LVTh assigning 1 point to each of these variables (anterior infarction, CMR-LVEF <50% and MVO >3.5 segments), which allowed us to stratify the risk of LVTh in the first 6 months after STEMI (0.6% if 0 points, 3.8% if 1 point, 14.4% if 2 points, and 31.2% if 3 points).

Conclusions

CMR imaging soon after STEMI can contribute relevant prognostic value regarding LVTh occurrence after the acute event. Patients with anterior infarction, LVEF <50% and MVO in >3.5 segments at early (1-week) CMR have the highest risk of LVTh in the first 6 months after STEMI.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Instituto de Salud Carlos III and “Fondos Europeos de Desarrollo Regional FEDER” and Conselleria de Educaciόn – Generalitat Valenciana.

A novel clinical and cardiac magnetic resonance risk score for early risk prediction after ST-segment elevation myocardial infarction

Background

Cardiac magnetic resonance (CMR) performed early after ST-segment elevation myocardial infarction (STEMI) can improve major adverse cardiac event (MACE) risk prediction. However, predictive models including clinical and CMR variables are scarce and not routinely implemented in clinical practice.

Purpose

We aimed to create a simple clinical-CMR risk score for early MACE risk stratification in STEMI patients.

Methods

We performed a multicenter prospective registry in three Spanish university hospitals of reperfused STEMI patients (n=1118) in whom early (1-week) CMR-derived left ventricular ejection fraction (LVEF), infarct size and microvascular obstruction (MVO) were quantified. MACE was defined as a combined clinical endpoint of cardiovascular (CV) death, non-fatal myocardial infarction (NF-MI) or re-admission for acute decompensated heart failure (HF), whichever occurred first. Univariate and multivariate analyses were performed and a risk score was computed using the variables which independently predicted the risk of MACE.

Results

During a median follow-up of 5.52 [2.63–7.44] years, 216 first MACE (58 CV deaths, 71 NF-MI and 87 HF) were registered. Mean age was 59.3±12.3 years and most patients (82.8%) were male. Based on the four variables independently associated with MACE, we computed an 8-point risk score: time to reperfusion >4.15h (1 point), GRACE risk score >155 (3 points), CMR-LVEF <40% (3 points), and MVO >1.5 segments (1 point). This score permitted MACE risk stratification: MACE per 100 person-years was 1.96 in the low-risk category (0–2 points), 5.44 in the intermediate-risk category (3–5 points), and 19.7 in the high-risk category (6–8 points): p<0.001 in multivariable Cox survival analysis.

Conclusions

A novel risk score including clinical (time to reperfusion >4.15h and GRACE risk score >155) and CMR (LVEF <40% and MVO >1.5 segments) variables allows for simple and straightforward MACE risk stratification early after STEMI. External validation should confirm the applicability of the risk score.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Instituto de Salud Carlos III and Fondo Europeo de Desarrollo Regional (FEDER) and Sociedad Española de Cardiología.

Cardiac magnetic resonance predictors of readmission for heart failure in elderly vs not elderly patients after ST-segment elevation myocardial infarction

Background

Patients with ST-segment elevation acute myocardial infarction (STEMI) have an increased risk of re-admission for acute heart failure (AHF). However, identification of patients at higher risk of AHF is challenging, especially in elderly individuals. The implications of cardiac magnetic resonance (CMR) imaging soon after the acute event for this specific purpose are unknown.

Purpose

We aim to study the clinical and CMR predictors of AHF in elderly and not elderly patients after STEMI.

Methods

STEMI patients treated with percutaneous coronary intervention and discharged from three university hospitals were included in a multicenter registry. We registered baseline clinical characteristics, echocardiographic parameters and early (1-week) CMR parameters - left ventricular ejection fraction (LVEF, %), infarct size (% of left ventricular mass) and microvascular obstruction (MVO, number of segments). Univariate and multivariate comparisons were performed in elderly (>70 years) and not elderly (≤70 years) patients to predict AHF during follow-up.

Results

The cohort was comprised of 759 patients, of which 177 (23.3%) were elderly (>70 years). During a mean follow-up of 5.23±3.54 years, 79 (10.4%) patients presented AHF. In not elderly patients, Killip class at admission (HR 2.05 [1.32–3.17], p=0.001), anterior infarction (HR 3.43 [1.13–10.36], p=0.03) and CMR-LVEF (HR 0.94 [0.91–0.98] per increased %, p=0.001) independently predicted AHF. However, a combined risk score comprising these variables was not superior to CMR-LVEF alone to predict AHF during follow-up (AUC 0.81 [0.74–0.88] vs. 0.81 [0.73–0.88], p=NS). In elderly patients, CMR-LVEF was the only predictor of AHF in the final multivariable model (HR 0.94 [0.91–0.97], p<0.001), although its predictive power was moderate (AUC 0.68 [0.56–0.80], p=0.001). Most AHF events in the not elderly subgroup occurred in patients with reduced (≤40%) CMR-LVEF (71%), while in the elderly subgroup AHF occurred more frequently in patients with preserved (≥50%, 30%) or mildly reduced (40–49%, 32%) CMR-LVEF than reduced (≤40%) CMR-LVEF (38%).

Conclusions

LVEF quantified by CMR soon after STEMI can accurately predict the risk of AHF in not elderly (≤70 years) patients and identify those individuals at higher risk (i.e. CMR-LVEF ≤40%). However, in elderly (>70 years) patients most AHF occur in patients with CMR-LVEF >40%, emphasizing the need for better predictive strategies in this population.

Funding Acknowledgement

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Instituto de Salud Carlos III and “Fondos Europeos de Desarrollo Regional FEDER” and Conselleria de Educaciόn – Generalitat Valenciana.

Collagen bundle orientation by Fourier analysis in myocardial infarction scarring

Funding Acknowledgements

Type of funding sources: Public grant(s) – EU funding. Main funding source(s): “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER” and Conselleria de Educación – Generalitat Valenciana.

Introduction

After acute myocardial infarction (AMI), the lack of oxygen and nutrients leads to cardiomyocyte necrosis and eventually to the formation of a collagen-based scar. Infarct scar characteristics, such as collagen bundle orientation, have a relevant influence on scar mechanics, the occurrence of cardiac arrhythmias, left ventricular dilation or aneurysm formation, wall stiffness, and the development of wall rupture or heart failure. However, the most adequate method for collagen bundle orientation (CBO) measurement in myocardial scar is not established.

Purpose

We aim to compare the measurement of collagen bundle orientation in infarct scar by Fourier analysis in three different histopathological techniques.

Methods

Juvenile swine (n=21) were subjected, by means of percutaneous balloon inflation, to a transient 90-min occlusion of mid left anterior descending artery followed by one month of reperfusion (chronic AMI group). Samples were obtained from the infarcted zone and stained with Masson’s trichrome, Picrosirius red and Haematoxylin-Eosin (H-E) standard protocols. Five microphotographs of the myocardial scar were taken at 200x magnification with light, polarised and confocal microscopy, respectively. A single observer measured CBO by means of Fast Fourier Transform analysis using a semi-automated protocol. Comparability between techniques was studied by the Intraclass Correlation Coefficient (ICC), the coefficient of variation (CV) and the Bland-Altman (B&A) plots and limits of agreement.

Results

Measurement of CBO in Masson’s trichrome tended to show higher (more "random-oriented") values than in Picrosirius and H-E+confocal techniques (ICC 0.79 and 0.7, p=0.001 and 0.005; B&A 0.29 to -0.02 and 0.43 to 0.01; CV 6.97% and 12.98%, respectively). However, measurement of CBO in Picrosirius and H-E+confocal techniques showed an "almost perfect" agreement (ICC 0.84, p<0.001; B&A 0.28 to -0.09; CV 17.33%). Selective staining and/or visualization of collagen in these latter techniques may underlie our findings, contrary to non-selective Masson’s trichrome.

Conclusion

Picrosirius red staining (visualized with polarised microscopy) and Haematoxylin-Eosin (visualized with confocal microscopy) are comparable in terms of collagen bundle orientation measurement by Fourier analysis in an animal model of chronic infarct scar. Masson’s trichrome (visualized with light microscopy) tends to show more "random-oriented" values, potentially due to non-specific staining and visualization of non-collagenous structures such as cells, and should not be recommended for this specific purpose.

Sex differences in mortality in stable patients undergoing vasodilator stress cardiovascular magnetic resonance

Introduction

The prognostic value and therapeutic implications of ischemia as derived from vasodilator stress cardiovascular magnetic resonance (CMR) could differ in men and women, but it has not been stablished.

Purpose

We assessed the influence of the ischemic burden as derived from CMR on the risk of death and the effect of revascularization across sex.

Methods

We evaluated 6,237 consecutive patients with known or suspected chronic coronary syndrome (CCS). Extensive ischemia was defined as >5 segments with perfusion deficit. Multivariate Cox proportional hazard regression models were used.

Results

A total of 2,371 (38.0%) patients were women and 583 (9.3%) underwent CMR-related revascularization. During a median follow-up of 5.13 years, 687 (11.0%) deaths were reported. We found an adjusted differential effect of CMR-derived ischemic burden across sex (p-value for interaction=0.039). Women exhibited an adjusted lower risk of death along most of the continuous ischemic burden but equalled men's risk when extensive ischemia was present. Likewise, CMR-related revascularization was shown to be differentially associated with the risk of mortality across sex (p-value for interaction=0.025). In patients with non-extensive ischemia, revascularization was related to a higher risk of death, with a greater extent in women. At higher ischemic burden, revascularization was associated with a lower risk in men, with more uncertain results in women.

Conclusions

CMR-derived ischemic burden allows predicting the risk of death and gives insight into the potential effect of revascularization in men and women with CCS. Compared to men, women with nonextensive ischemia displayed a lower risk and a similar risk with a higher ischemic burden. The impact of CMR-related revascularization on mortality risk was also significantly different according to ischemic burden and sex.

Funding Acknowledgement

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): This study was supported by the Instituto de Salud Carlos III and cofunded by the European Regional Development Fund (ERDF).

Clinical applicability of echocardiographic strict negative criteria for suspected infective endocarditis

Introduction

Infective endocarditis (IE) is an uncommon but potentially lethal disease that requires a timely diagnosis. Echocardiography has a pivotal role in EI diagnosis, but this may lead to an overuse of this technology in clinical daily practice, and it is unclear which patients can benefit from a follow-up study if the initial transthoracic echocardiogram (TTE) shows no signs of IE. The strict negative criteria (good ultrasound quality and no high-risk features such as significant valvular regurgitations or stenosis, pericardial effusion or intracardiac devices) 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 potential applicability of the strict negative criteria.

Methods

We retrieved all the echocardiograms that were performed in our center for suspected or confirmed IE between January 2014 and December 2018. We defined different groups according to the strict negative criteria and reviewed the electronic clinical history to check if a definitive diagnosis of IE was established or not.

Results

We included a total of 905 TTEs. 451 (49.8%) of them fulfilled the strict negativity criteria (Group 1). In this group, IE was seldom diagnosed (n=4, 0.9%). In 338 (37.4%) patients no signs of IE were evident but they didn't fulfill the strict negative criteria (Group 2). A follow-up echocardiogram and definitive diagnosis of IE were more frequent (n=48, 14.2% and n=20, 5.9%). Finally, in 116 (12.8%) patients the initial TEE showed typical or suggestive signs of IE, in whom the diagnosis was confirmed in 48 (41.4%). The independent predictors of follow-up echocardiography were the previous history of valvular heart disease (HR 2.38 [1.39–3.89], p=0.001) or cancer (HR 0.47 [0.27–0.84], p=0.01), positive blood cultures for Enterococcus (HR 5.01 [2.34–10.73], p<0.001), methicillin-sensitive Staphylococcus aureus (HR 2.8 [1.27–6.17], p=0.011) or Streptococcus (HR 2.36 [1.12–5], p=0.024), and the presence of typical or suggestive signs of infective endocarditis on initial TTE (HR 13.77 [8.6–22.05], p<0.001). A definitive diagnosis of IE was confirmed in a minority of the study population (n=72, 8%). Only one readmission for underdiagnosis of IE during index hospitalization was noted on Group 2.

Conclusions

In a real-life, observational setting only a minority of patients in whom IE was suspected had a definite diagnosis. An initial TTE for suspected IE fulfilling the strict negative criteria predicts both a low probability of requesting a follow-up study and of a definitive diagnosis of IE. Further research should be performed to rationalize echocardiogram requests for suspected IE.

Funding Acknowledgement

Type of funding sources: None.

A novel clinical and stress cardiac magnetic resonance score to predict long-term all-cause mortality in patients with known or suspected chronic coronary syndrome

Background

Vasodilator stress cardiac magnetic resonance (stressCMR) has shown robust diagnostic and prognostic value in patients with known or suspected chronic coronary syndrome (CCS). However, it is unknown whether integration of several prognostic stressCMR parameters, such as the ischemic burden (number of segments with first-pass stress-induced perfusion defects -PD-) and left ventricular ejection fraction (LVEF), with clinical variables can improve risk prediction in this population.

Purpose

We aim to explore the usefulness of a clinical-stressCMR score to predict the risk of all-cause mortality in patients with known or suspected CCS submitted to undergo a stressCMR.

Methods

We included 6187 patients in a large prospective multicenter registry (mean age 65.18±11.51 years, 37.3% female) which underwent stressCMR for known or suspected CCS. Several clinical and stressCMR variables were collected, such as LVEF, end-diastolic and end-systolic volume indices, ischemic burden and segments with necrosis (with late gadolinium enhancement imaging).

Results

During a mean and median follow-up of 5.85±3.82 years we registered 682 (11%) all-cause deaths. Several clinical and all stressCMR variables were associated with all-cause mortality in univariate analysis. However, the only independent predictors of all-cause mortality in multivariate analysis were age (HR 1.07 [1.06–1.08] per year, p<0.001), male sex (HR 1.36 [1.15–1.61], p<0.001), diabetes mellitus (HR 1.6 [1.37–1.87], p<0.001), LVEF (0.98 [0.97–0.98] per %, p<0.001) and ischemic burden (HR 1.04 [1.02–1.06] per segment with stress-induced PD, p=0.001). By means of the chi-square increase at each step of the stepwise multiparametric Cox regression we created a clinical-stressCMR score that included these variables (age, male sex, diabetes mellitus, LVEF and ischemic burden) kept in their continuous state if possible. This score showed a good performance to predict all-cause mortality (area under the curve = 0.716 [0.697–0.735], p<0.001). Dividing the population into quintiles according to the clinical-stressCMR score allowed for a stratification of the annualized risk of all-cause mortality (0.39%/year, 0.94%/year, 1.62%/year, 2.63%/year and 3.83%/year, respectively; log-rank 420.33 and p<0.001 for Kaplan-meier curves).

Conclusions

A novel clinical-stressCMR, which includes clinical (age, male sex, and diabetes mellitus) and stressCMR (LVEF and ischemic burden) variables, can provide robust prediction and stratification of the risk of all-cause mortality in a population of patients with know or suspected CCS.

Figure 1. Clinical-stress CMR score

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This study was funded by “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER” (PIE15/00013, PI17/01836, and CIBERCV16/11/00486 grants) and by Generalitat Valenciana (GV/2018/116).

Chest pain of unknown coronary origin: can exercise ECG testing contribute to long-term risk prediction on top of vasodilator stress cardiac magnetic resonance?

Background

The prognostic value of both exercise ECG testing (ExECG) and vasodilator stress cardiac magnetic resonance (VS-CMR) is well-known in patients with chest pain of unknown coronary origin. However, it is unknown whether performing both techniques can improve the risk stratification of these patients.

Purpose

We aim to confirm the additive prognostic value of ExECG and VS-CMR in a real-world cohort of patients with chest pain of unknown coronary origin.

Methods

We retrospectively included 288 patients in which ExECG and VS-CMR had been subsequently performed within one year. Clinical, ExECG and VS-CMR variables were registered. We performed univariate and multivariate analysis to check for the association of variables with the risk of MACE, defined as a combined endpoint of acute coronary syndrome (ACS), admission for heart failure (aHF) or all-cause death.

Results

During a mean follow-up of 4.2±2.15 years, we registered 27 MACE (15 ACS, 8 aHF and 8 all-cause deaths). The history of hypertension, previous coronary artery disease and/or coronary artery bypass grafting, lower maximal heart rate during ExECG (maxHR) and more extensive ischemic burden (segments with perfusion defects -PD- on stress first-pass perfusion) and myocardial necrosis (number of segments with necrosis at late gadolinium enhancement imaging) associated with the MACE endpoint. However, the only independent predictors of MACE were maxHR during ExECG (HR 0.98 [0.96–0.99], p=0.01) and more extensive segments with PD in the VS-CMR (HR 1.2 [1.07–1.34], p=0.002). We identified the best cut-off using the Youden index derived from receiver operating characteristics (ROC) analysis to predict MACE - it was ≤130bpm for maxHR during ExECG and ≥2 segments with PD on VS-CMR. These cathegories allowed us to stratify the annualized rate of MACE, which was very low (0.97%/year) in patients with normal maxHR and no PD on VS-CMR, intermediate in patients with only abnormal maxHR (1.98%/year) or PD on VS-CMR (3.24%/year) and high in patients with both abnormal maxHR and segments with PD (6.26%/year). Adding maxHR to the multivariable model including stress-induced PD by VS-CMR significantly improved the predictive power of MACE as derived from the continuous reclassification improvement index (0.47 [0.10–0.81], p<0.05).

Conclusions

ExECG and VS-CMR can have an additive prognostic value to predict the long-term risk of MACE in patients with chest pain of unknown coronary origin. Patients with maxHR during ExECG ≤130bpm and ≥2 segments with PD on VS-CMR are at the highest risk of MACE.

Figure 1. MACE risk stratification.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This study was funded by “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER” (PIE15/00013, PI17/01836, and CIBERCV16/11/00486 grants) and by Generalitat Valenciana (GV/2018/116).

Complete revascularization of non-culprit lesions in stemi is associated with improved myocardial salvage and reduced microvascular obstruction: a cardiac magnetic resonance study

Background

The COMPLETE trial showed that routine and complete Percutaneous Coronary Intervention (PCI) of non-infarct related artery (non-IRA) lesions in STEMI was associated with a significant reduction in the rates of death or new myocardial infarction. However, whether this benefit is related to improved myocardial salvage and left ventricular (LV) function is unknown.

Methods

We prospectively included 465 patients with first STEMI reperfused by primary PCI. Late gadolinium-enhanced Cardiac Magnetic Resonance (CMR) was obtained during admission to measure the area at risk (AAR), IRA-infarct size (IS) as % LV mass, and myocardial salvage index (MSI) as % of AAR. The study was repeated in 392 of them at 6 months follow-up to compute LV volumes and ejection fraction (EF).

Results

Patients with three-vessel disease had larger IS than those with two or single vessel disease (25.4±14.5% vs 19.0±13.1% vs 19.0±12.8% LV mass respectively, p<0.05), despite no differences in AAR (33±11% LV mass for all). Accordingly, MSI decreased progressively for one, two or three-vessel disease (42.4±31.4 vs 41.5±30.6 vs 25.1±31.3% AAR respectively, p<0.01). The number of myocardial segments with microvascular obstruction (MVO) was also higher for three-vessel disease (1.9±1.9) than for two (1.1±1.7) or single-vessel disease (1.2±1.8), p<0.05. Mean follow-up EF also decreased progressively with the number of vessels involved (50.7±9.4, 49.1±11.4 and, 44.4±11.2% respectively, p<0.01). A total of 183 patients had multivessel disease. Among them, those with complete revascularization (n=51) had larger MSI (46.4±35.2 vs 34.5±29.3% AAR, p<0.04) and were less likely to have MVO phenomenon (28.6 vs 49.2%, p<0.05). However, no significant differences in the change in EF was observed between both groups (ΔEF:+4.4±6.2 vs +4.3±6.2%, p=0.985 for the interaction).

Conclusion

The presence and extent of multivessel disease influence myocardial salvage and MVO following primary PCI in STEMI. Improvement in myocardial salvage in the IRA territory and a reduction in microvascular obstruction may mediate the beneficial effects of complete revascularization.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): Fundaciό La Marato TV3 2015303132, FIS PI15/00531. Partially funded with FEDER funds.

Impact of the dynamics of ejection fraction on risk stratification in a large multicenter registry of STEMI patients using sequential CMR

Background

Left ventricular ejection fraction (LVEF) has traditionally been used as the cornerstone for risk stratification after ST-segment elevation myocardial infarction (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) has been demonstrated.

Purpose

We explored the impact of sequential assessment of CMR-derived LVEF on dynamic risk stratification after STEMI.

Methods

Data were obtained from three prospective registries of reperfused STEMI patients (n=1036) in whom LVEF, IS and MVO were sequentially quantified by CMR (at least at 1 week and at 6 months). Major adverse cardiac events (MACE) were defined as a combined clinical end-point: death or re-admission for acute heart failure (HF), whichever occurred first. Late events were regarded as those occurring after the 6-month CMR.

Results

During a mean and median follow-up of 5 years, 105 first MACE (10%, 36 deaths and 69 HF) and 82 late MACE (8%, 35 deaths and 47 HF) were registered. From 1-week to 6-month CMR, LVEF improved (49±12 vs. 53±12%), IS decreased (21±14 vs 17±12% of LV mass) and MVO vanished (1.3±1.9 vs. 0.1±0.7% of LV mass), p<0.001 for all comparisons. At 1-week CMR, 207 patients (20%) displayed reduced LVEF (r-LVEF, <40%), 328 (32%) mid-range LVEF (mr-LVEF, 40–50%) and 501 (48%) preserved LVEF (p-LVEF, >50%). At 6-month CMR, 144 patients (14%) displayed r-LVEF, 247 (24%) mr-LVEF and 645 (62%) p-LVEF. The total MACE rate was higher (p<0.001) only in patients with r-LVEF at 1 week (22%) vs. 7% in those with mr-LVEF and 7% in those with p-LVEF. Similarly, the late MACE rate was higher (p<0.001) only in patients with r-LVEF at 6 months (20%) vs. 7% in those with mr-LVEF and 5% in those with p-LVEF. The late MACE rate was very low in patients with sustained mr- or p-LVEF (41/794, 5%), intermediate in those with improved LVEF from r-LVEF at 1 week to mr- or p-LVEF at 6 months (12/98, 12%) and high in patients with sustained r-LVEF (22/109, 20%) or worsened LVEF from mr- or p-LVEF at 1 week to r-LVEF at 6 months (7/35, 20%), p<0.001 for the trend. Using a Markov approach, only r-LVEF (at any time assessed) significantly related to a higher MACE rate.

Conclusions

Of available CMR parameters, LVEF persists as the pivotal index for simple post-STEMI risk stratification. Mid-range or preserved LVEF in acute phase associates with excellent long-term outcome. Changes in LVEF provide valuable dynamic prognostic information. Maintenance of mid-range or preserved LVEF in chronic phase occurs in the majority of patients and associates with a very low risk of late clinical events. Whereas late improvement reaching at least mid-range LVEF exerts salutary effects, detection of reduced LVEF at this point identifies the small subset of patients at high risk in the long term.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This study was funded by “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER” (PIE15/00013, PI17/01836, and CIBERCV16/11/00486 grants).

Risk stratification in patients discharged for STEMI. Ejection fraction by echocardiography as the gatekeeper for a selective use of cardiac magnetic resonance

Background

CMR permits robust risk stratification of discharged STEMI patients but an indiscriminate use in all cases is unfeasible.

Purpose

We evaluated the usefulness of left ventricular ejection fraction (LVEF) by echocardiography (Echo) as the gatekeeper for identifying those patients discharged for ST-segment elevation myocardial infarction (STEMI) who benefit most from cardiac magnetic resonance (CMR) for prognostic purposes.

Methods

Echo and CMR were performed in 1119 patients discharged for STEMI included in a multicenter registry. The prognostic power of CMR beyond Echo-LVEF was assessed using C-statistic, net reclassification index (NRI) and integrated discrimination improvement index (IDI).

Results

During a 4.8-year median follow-up, 136 (12%) first major adverse cardiac events (MACE) occurred (47 cardiovascular deaths and 89 re-admissions for acute heart failure). Lesser Echo-LVEF and CMR-LVEF associated with the occurrence of MACE but only CMR-LVEF and microvascular obstruction were independent predictors. The MACE rate significantly increased only in patients with CMR-LVEF <40% (≥50%: 7%, 40–49%: 9%, <40%: 27%, p<0.001). The majority of patients (629, 56%) displayed Echo-LVEF ≥50% and most of them (94%) were at the “safe zone” (CMR-LVEF >40%). On the other hand, 490 patients (44%) exhibited Echo-LVEF <50% and 33% of them were incorrectly classified either in the “safe zone” (CMR-LVEF ≥40%) or in the “risk zone” (CMR-LVEF <40%). C-statistic, NRI and IDI demonstrated potent reclassification for MACE prediction by CMR in patients with Echo-LVEF <50% but not in those with Echo-LVEF ≥50%.

Conclusions

Echo-LVEF <50% identifies the subset of discharged STEMI patients who may benefit most from CMR in terms of long-term risk prediction.

Figure 1. LVEF reclassification

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This study was funded by “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER” (PIE15/00013, PI17/01836, and CIBERCV16/11/00486 grants).

Implication of anti-angiogenic VEGF-A165b in angiogenesis and systolic function after reperfused myocardial infarction

Background

Angiogenesis participates in re-establishing microcirculation after myocardial infarction (MI).

Purpose

In this study, we aim to further understand the role of the anti-angiogenic isoform vascular endothelial growth factor (VEGF)-A165b after MI and explore its potential as a co-adjuvant therapy to coronary reperfusion.

Methods

Two mice MI models were formed: 1) permanent coronary ligation (non-reperfused MI), 2) transient 45-min coronary occlusion followed by reperfusion (reperfused MI); in both models, animals underwent echocardiography before euthanasia at day 21 after MI induction. Serum and myocardial VEGF-A165b levels were determined. In both experimental MI models, functional and structural implication of VEGF-A165b blockade was assessed. In a cohort of 104 ST-segment elevation MI patients, circulating VEGF-A165b levels were correlated with cardiovascular magnetic resonance-derived left ventricular ejection fraction at 6-months and with the occurrence of adverse events (death, heart failure and/or re-infarction).

Results

In both models, circulating and myocardial VEGF-A165b presence was increased 21 days after MI induction. Serum VEGF-A165b levels inversely correlated with systolic function evaluated by echocardiography. VEGF-A165b blockage increased capillary density, reduced infarct size, and enhanced left ventricular function in reperfused, but not in non-reperfused MI experiments. In patients, higher VEGF-A165b levels correlated with depressed ejection fraction and worse outcomes.

Conclusions

In experimental and clinical studies, higher serum VEGF-A165b levels associates with a worse systolic function. Its blockage enhances neoangiogenesis, reduces infarct size, and increases ejection fraction in reperfused, but not in non-reperfused MI experiments. Therefore, VEGF-A165b neutralization represents a potential co-adjuvant therapy to coronary reperfusion.

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This study was funded by “Instituto de Salud Carlos III” and “Fondos Europeos de Desarrollo Regional FEDER” (Exp. PIE15/00013, PI17/01836, PI18/00209 and CIBERCV16/11/00486).

P1475Risk stratification after STEMI. Ejection fraction by echocardiography as the gatekeeper for a selective use of cardiac magnetic resonance

Introduction

Cardiac magnetic resonance (CMR) has emerged as the most potent non-invasive imaging technique for risk stratification after ST-segment elevation myocardial infarction (STEMI) but an indiscriminate use in all patients is unfeasible. Echocardiography (Echo) has been universally used for prognostication in this scenario. We hypothesized that left ventricular ejection fraction (LVEF) by Echo can represent the gatekeeper for selecting those patients who benefit most from CMR for prognostic purposes.

Methods

Data were obtained from a large prospective registry of reperfused STEMI patients (n=516) in whom Echo (2D and Doppler variables) and CMR (cine images, microvascular obstruction and infarct size) were simultaneously recorded at pre-discharge (7±2 days). Major adverse cardiac events (MACE) were defined as a combined clinical end-point: death or re-admission for acute heart failure (whichever occurred first). Patients were categorized in reduced LVEF (r-LVEF, <40%), mid-range LVEF (mr-LVEF, 40–49%) and preserved LVEF (p-LVEF, ≥50%). Hierarchical multivariate Cox regression analyses including first clinical+Echo variables and then CMR variables where carried out. C-statistics, “net reclassification” (NRI) and “integrated discrimination” (IDI) indexes were obtained.

Results

During a mean and median follow-up of 4 years, 86 first MACE (17%) were registered (39 deaths and 47 re-admissions for acute heart failure). In the whole study group (n=516), the independent predictors of MACE were time to revascularization (min), GRACE score, CMR-LVEF (%) and CMR-microvascular obstruction (% of LV mass); C-statistic 0.82 (p<0.001). The MACE rate in patients with r-LVEF, mr-LVEF and p-LVEF was 47%, 23% and 11% by Echo-LVEF and 45%, 17% and 8% by CMR-LVEF. LVEF was lower by CMR than by Echo (51±13 vs. 54±10, p<0.001) and r-LVEF was more frequently detected by CMR (n=94, 18%) than by Echo (n=48, 9%), p<0.001. CMR significantly improved clinical+Echo stratification in those 112 patients (22%) with mr-Echo-LVEF (C-statistitics 0.74 vs 0.82; NRI and IDI: p<0.05) but it did not in those 355 patients (69%) with p-Echo-LVEF (C-statistitics 0.75 vs 0.76; NRI and IDI: non-significant) and in those 49 patients (9%) with r-Echo-LVEF (C-statistitics 0.77 vs 0.77; NRI and IDI: non-significant).

Figure 1. Risk stratification after STEMI

Conclusions

Applied in an individualized manner, Echo-LVEF appears as a useful gatekeeper for a selective use of CMR soon after STEMI for prognostic purposes. The event rate is high in patients with reduced Echo-LVEF and low in those with preserved Echo-LVEF; CMR does not seem to significantly improve risk stratification in these scenarios. Nevertheless, the occurrence of mid-range Echo-LVEF permits discriminating the specific subset of STEMI patients (less than a quarter) who really benefit from pre-discharge CMR in terms of risk assessment.

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).

393Ischemic burden by vasodilator stress CMR predicts long-term all-cause death and the effect of revascularization in patients with known or suspected stable ischemic heart disease

Background

In patients with stable ischemic heart disease (SIHD) the effect of revascularization on all-cause death (the most verifiable clinical event) is unknown.

Objectives

We explored the potential of the ischemic burden as derived from vasodilator stress cardiovascular magnetic resonance (CMR) to guide decision-making in this scenario.

Methods

In a large prospective multicenter registry, we recruited 6389 patients (mean age 65±11 years, 38% female) submitted to undergo vasodilator stress CMR for known or suspected SIHD. Baseline and CMR characteristics were prospectively recorded. The ischemic burden (at vasodilator stress first-pass perfusion imaging) and necrosis extent (at late enhancement imaging) were computed (17-segment model). The effect of CMR-related revascularization (within the following three months) on all-cause death (revised using the unified regional electronic health system registry) was explored.

Results

During a 5.75-year median follow-up, 717 (11.2%) all-cause deaths were documented. In multivariable analyses, more extensive ischemic burden (per 1-segment increase) independently related to all-cause death (1.05 [1.03–1.07], p<0.001). In 1034 patients (517 revascularized, 517 non-revascularized) strictly 1:1 matched for the independent predictors of outcome and of undergoing CMR-related revascularization (age, diabetes mellitus, male sex, LVEF, ischemic burden and necrosis extent), CMR-related revascularization did not significantly alter all-cause death rate (13.3% vs. 13.3%, p=0.54). Nevertheless, a potent interaction existed with the ischemic burden (p<0.001). CMR-related revascularization independently reduced the risk of all-cause death in 430 patients with ischemic burden >5 segments (9.3% vs. 16.3%, HR 0.56 [0.32–0.98], p=0.02) but it independently increased risk in 604 patients with ischemic burden ≤5 segments (16.2% vs. 11.3%, HR 1.59 [1.03–2.45], p=0.037).

Figure 1. CMR-related revascularization

Conclusions

In patients with known or suspected stable ischemic heart disease the ischemic burden as derived from vasodilator stress CMR can be helpful to predict the effect of revascularization on long-term all-cause death.

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).