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1.

Objectives

The aim of this study was to evaluate the prognostic value of strain as assessed by tissue tracking (TT) cardiac magnetic resonance (CMR) soon after ST-segment elevation myocardial infarction (STEMI).

Background

The prognostic value of myocardial strain as assessed post-STEMI by TT-CMR is unknown.

Methods

The authors studied the prognostic value of TT-CMR in 323 patients who underwent CMR 1 week post-STEMI. Global (average of peak segmental values [%]) and segmental (number of altered segments) longitudinal (LS), circumferential, and radial strain were assessed using TT-CMR. Global and segmental strain cutoff values were derived from 32 control patients. CMR-derived left ventricular ejection fraction, microvascular obstruction, and infarct size were determined. Results were validated in an external cohort of 190 STEMI patients.

Results

During a median follow-up of 1,085 days, 54 first major adverse cardiac events (MACE), which included 10 cardiac deaths, 25 readmissions for heart failure, and 19 readmissions for reinfarction were documented. MACE was associated with more severe abnormalities in all strain indexes (p < 0.001), although only global LS was an independent predictor (p < 0.001). The MACE rate was higher in patients with a global LS of ≥?11% (22% vs. 9%; p = 0.001). After adjustment for baseline and CMR variables, global LS (hazard ratio [HR]: 1.21; 95% confidence interval [CI]: 1.11 to 1.32; p < 0.001) was associated with MACE. In the external validation cohort, a global LS ≥?11% was seen in a higher proportion of patients with MACE (34% vs. 9%; p < 0.001). Global LS predicted MACE after adjustment for baseline and CMR variables (HR: 1.18; 95% CI: 1.04 to 1.33; p = 0.008). The addition of global LS to the multivariate models, including baseline and CMR variables, did not significantly improve the categorical net reclassification improvement index in either the study group (?0.015; p = 0.7) or in the external validation cohort (?0.019; p = 0.9).

Conclusions

TT-CMR provided prognostic information soon after STEMI. However, it did not substantially improve risk reclassification beyond traditional CMR indexes.  相似文献   

2.

Objectives

This study sought to investigate whether early post-infarction cardiac magnetic resonance (CMR) parameters provide additional long-term prognostic value beyond traditional outcome predictors in ST-segment elevation myocardial infarction (STEMI) patients.

Background

Long-term prognostic significance of CMR in STEMI patients has not been assessed yet.

Methods

This was a longitudinal study from a multicenter registry that prospectively included STEMI patients undergoing CMR after infarction. Between May 2003 and August 2015, 810 revascularized STEMI patients were included. CMR was performed at a median of 4 days after STEMI. Infarct size, microvascular obstruction (MVO), and left ventricular (LV) volumes and function were measured. Primary endpoint was a composite of all death and decompensated heart failure (HF).

Results

During median follow-up of 5.5 years (range 1.0 to 13.1 years), primary endpoint occurred in 99 patients (39 deaths and 60 HF hospitalization). MVO was a strong predictor of the composite endpoint after correction for important clinical, CMR, and angiographic parameters, including age, LV systolic function, and infarct size. The independent prognostic value of MVO was confirmed in all multivariate models irrespective of whether it was included as a dichotomous (presence of MVO, hazard ratio [HR]: 1.985 to 1.995), continuous (MVO extent as % LV, HR: 1.095 to 1.097), or optimal cutoff value (MVO extent ≥2.6% of LV; HR: 3.185 to 3.199; p < 0.05 for all). MVO extent ≥2.6% of LV was a strong independent predictor of all death (HR: 2.055; 95% confidence interval: 1.076 to 3.925; p = 0.029) and HF hospitalization (HR: 5.999; 95% confidence interval: 3.251 to 11.069; p < 0.001). Finally, MVO extent ≥2.6% of LV provided incremental prognostic value over traditional outcome predictors (net reclassification improvement index: 0.16 to 0.30; p < 0.05 for all models).

Conclusions

Early post-infarction CMR-based MVO is a strong independent prognosticator in revascularized STEMI patients. Remarkably, MVO extent ≥2.6% of LV improved long-term risk stratification over traditional outcome predictors.  相似文献   

3.

Objectives

This study sought to determine the incidence and prognostic significance of persistent iron in patients post–ST-segment elevation myocardial infarction (STEMI).

Background

The clinical significance of persistent iron within the infarct core after STEMI complicated by acute myocardial hemorrhage is poorly understood.

Methods

Patients who sustained an acute STEMI were enrolled in a cohort study (BHF MR-MI [Detection and Significance of Heart Injury in ST Elevation Myocardial Infarction]). Cardiac magnetic resonance imaging including T2* (observed time constant for the decay of transverse magnetization seen with gradient-echo sequences) mapping was performed at 2 days and 6 months post-STEMI. Myocardial hemorrhage or iron was defined as a hypointense infarct core with T2* signal <20 ms.

Results

A total of 203 patients (age 57 ± 11 years, n = 158 [78%] male) had evaluable T2* maps at 2 days and 6 months post-STEMI; 74 (36%) patients had myocardial hemorrhage at baseline, and 44 (59%) of these patients had persistent iron at 6 months. Clinical associates of persistent iron included heart rate (p = 0.009), the absence of a history of hypertension (p = 0.017), and infarct size (p = 0.028). The presence of persistent iron was associated with worsening left ventricular (LV) end-diastolic volume (regression coefficient: 21.10; 95% confidence interval [CI]: 10.92 to 31.27; p < 0.001) and worsening LV ejection fraction (regression coefficient: ?6.47; 95% CI: ?9.22 to ?3.72; p < 0.001). Persistent iron was associated with the subsequent occurrence of all-cause death or heart failure (hazard ratio: 3.91; 95% CI: 1.37 to 11.14; p = 0.011) and major adverse cardiac events (hazard ratio: 3.24; 95% CI: 1.09 to 9.64; p = 0.035) (median follow-up duration 1,457 days [range 233 to 1,734 days]).

Conclusions

Persistent iron at 6 months post-STEMI is associated with worse LV and longer-term health outcomes. (Detection and Significance of Heart Injury in ST Elevation Myocardial Infarction [BHF MR-MI]; NCT02072850)  相似文献   

4.

Objectives

The aims of the study were to assess the prognostic significance of cardiac magnetic resonance myocardial feature tracking (CMR-FT) in a large multicenter study and to evaluate the most potent CMR-FT predictor of hard clinical events following myocardial infarction (MI).

Background

CMR-FT is a new method that allows accurate assessment of global and regional circumferential, radial, and longitudinal myocardial strain. The prognostic value of CMR-FT in patients with reperfused MI is unknown.

Methods

The study included 1,235 MI patients (n = 795 with ST-segment elevation MI and 440 with non–ST-elevation MI) at 15 centers. All patients were reperfused by primary percutaneous coronary intervention. Central core laboratory–masked analyses were performed to determine left ventricular (LV) circumferential, radial, and longitudinal strain. The primary clinical endpoint of the study was the occurrence of major adverse cardiac events within 12 months after infarction.

Results

Patients with cardiovascular events had significantly impaired CMR-FT strain values (p < 0.001 for all). Global longitudinal strain was identified as the strongest CMR-FT parameter of future cardiovascular events and emerged as an independent predictor of poor prognosis following MI even after adjustment for established prognostic markers. Global longitudinal strain provided an incremental prognostic value for all-cause mortality above LV ejection fraction (c-index increase from 0.65 to 0.73; p = 0.04) and infarct size (c-index increase from 0.60 to 0.78; p = 0.002).

Conclusions

CMR-FT is a superior measure of LV function and performance early after reperfused MI with incremental prognostic value for mortality over and above LV ejection fraction and infarct size. (Abciximab i.v. Versus i.c. in ST-segment elevation Myocardial Infarction [AIDA STEMI]; NCT00712101; Thrombus Aspiration in ThrOmbus Containing culpRIT Lesions in Non-ST-Elevation Myocardial Infarction [TATORT-NSTEMI]; NCT01612312)  相似文献   

5.

Objectives

The aim of this study was to evaluate whether native T1 value of the myocardium on cardiac magnetic resonance (CMR) could predict clinical events in patients with significant aortic stenosis (AS).

Background

Although previous studies have demonstrated the prognostic value of focal fibrosis using late gadolinium enhancement (LGE) by CMR in AS patients, the prognostic implication of diffuse myocardial fibrosis by noninvasive imaging remains unknown.

Methods

A prospective observational longitudinal study was performed in 127 consecutive patients with moderate or severe AS (68.8 ± 9.2 years of age, 49.6% male) and 33 age- and sex-matched controls who underwent 3-T CMR. The degree of diffuse myocardial fibrosis was assessed by noncontrast mapping of T1 relaxation time using modified Look-Locker inversion-recovery sequence, and the presence and extent of LGE were also evaluated. The AS patients were divided into 3 groups by the native T1 value. Primary endpoint was a composite of all-cause death and hospitalization for heart failure.

Results

Native T1 value was higher in AS patients, compared with control subjects (1,232 ± 53 ms vs. 1,185 ± 37 ms; p = 0.008). During follow-up (median 27.9 months), there were 24 clinical events including 9 deaths (6 pre-operative and 3 post-operative), the majority of which occurred in the patients in the highest T1 tertile group (2.4% vs. 11.6% vs. 42.9% for lowest, mid-, and highest tertile groups; p < 0.001 by log-rank test). The total number of events for both pre- and post-operative events also occurred more frequently in patients in the highest T1 tertile group. EuroSCORE II, the presence and/or extent of LGE, and the native T1 value were predictors of poor prognosis (adjusted hazard ratio for every 20-ms increase of native T1: 1.28; p = 0.003). In particular, the highest native T1 value provided further risk stratification regardless of the presence of LGE.

Conclusions

High native T1 value on noncontrast T1 mapping CMR is a novel, independent predictor of adverse outcome in patients with significant AS.  相似文献   

6.

Objectives

The aim of this study was to evaluate the effect of fractional flow reserve (FFR)–guided revascularization compared with culprit-only percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI) on infarct size, left ventricular (LV), function, LV remodeling, and the presence of nonculprit infarctions.

Background

Patients with STEMI with multivessel disease might have improved clinical outcomes after complete revascularization compared with PCI of the infarct-related artery only, but the impact on infarct size, LV function, and remodeling as well as the risk for periprocedural infarction are unknown.

Methods

In this substudy of the DANAMI-3 (Third Danish Trial in Acute Myocardial Infarction)–PRIMULTI (Primary PCI in Patients With ST-Elevation Myocardial Infarction and Multivessel Disease: Treatment of Culprit Lesion Only or Complete Revascularization) randomized trial, patients with STEMI with multivessel disease were randomized to receive either complete FFR-guided revascularization or PCI of the culprit vessel only. The patients underwent cardiac magnetic resonance imaging during index admission and at 3-month follow-up.

Results

A total of 280 patients (136 patients with infarct-related and 144 with complete FFR-guided revascularization) were included. There were no differences in final infarct size (median 12% [interquartile range: 5% to 19%] vs. 11% [interquartile range: 4% to 18%]; p = 0.62), myocardial salvage index (median 0.71 [interquartile range: 0.54 to 0.89] vs. 0.66 [interquartile range: 0.55 to 0.87]; p = 0.49), LV ejection fraction (mean 58 ± 9% vs. 59 ± 9%; p = 0.39), and LV end-systolic volume remodeling (mean 7 ± 22 ml vs. 7 ± 19 ml; p = 0.63). New nonculprit infarction occurring after the nonculprit intervention was numerically more frequent among patients treated with complete revascularization (6 [4.5%] vs. 1 [0.8%]; p = 0.12).

Conclusions

Complete FFR-guided revascularization in patients with STEMI and multivessel disease did not affect final infarct size, LV function, or remodeling compared with culprit-only PCI.  相似文献   

7.

Objectives

The aim of this study was to evaluate the prognostic value of cardiac magnetic resonance (CMR) feature-tracking–derived global longitudinal strain (GLS) in a large multicenter population of patients with ischemic and nonischemic dilated cardiomyopathy.

Background

Direct assessment of myocardial fiber deformation with GLS using echocardiography or CMR feature tracking has shown promise in providing prognostic information incremental to ejection fraction (EF) in single-center studies. Given the growing use of CMR for assessing persons with left ventricular (LV) dysfunction, we hypothesized that feature-tracking–derived GLS may provide independent prognostic information in a multicenter population of patients with ischemic and nonischemic dilated cardiomyopathy.

Methods

Consecutive patients at 4 U.S. medical centers undergoing CMR with EF <50% and ischemic or nonischemic dilated cardiomyopathy were included in this study. Feature-tracking GLS was calculated from 3 long-axis cine-views. The primary endpoint was all-cause death. Cox proportional hazards regression modeling was used to examine the association between GLS and death. Incremental prognostic value of GLS was assessed in nested models.

Results

Of the 1,012 patients in this study, 133 died during median follow-up of 4.4 years. By Kaplan-Meier analysis, the risk of death increased significantly with worsening GLS tertiles (log-rank p < 0.0001). Each 1% worsening in GLS was associated with an 89.1% increased risk of death after adjustment for clinical and imaging risk factors including EF and late gadolinium enhancement (LGE) (hazard ratio [HR]:1.891 per %; p < 0.001). Addition of GLS in this model resulted in significant improvement in the C-statistic (0.628 to 0.867; p < 0.0001). Continuous net reclassification improvement (NRI) was 1.148 (95% confidence interval: 0.996 to 1.318). GLS was independently associated with death after adjustment for clinical and imaging risk factors (including EF and late gadolinium enhancement) in both ischemic (HR: 1.942 per %; p < 0.001) and nonischemic dilated cardiomyopathy subgroups (HR: 2.101 per %; p < 0.001).

Conclusions

CMR feature-tracking–derived GLS is a powerful independent predictor of mortality in a multicenter population of patients with ischemic or nonischemic dilated cardiomyopathy, incremental to common clinical and CMR risk factors including EF and LGE.  相似文献   

8.

Objectives

The authors developed a fully automated framework to quantify myocardial blood flow (MBF) from contrast-enhanced cardiac magnetic resonance (CMR) perfusion imaging and evaluated its diagnostic performance in patients.

Background

Fully quantitative CMR perfusion pixel maps were previously validated with microsphere MBF measurements and showed potential in clinical applications, but the methods required laborious manual processes and were excessively time-consuming.

Methods

CMR perfusion imaging was performed on 80 patients with known or suspected coronary artery disease (CAD) and 17 healthy volunteers. Significant CAD was defined by quantitative coronary angiography (QCA) as ≥70% stenosis. Nonsignificant CAD was defined by: 1) QCA as <70% stenosis; or 2) coronary computed tomography angiography as <30% stenosis and a calcium score of 0 in all vessels. Automatically generated MBF maps were compared with manual quantification on healthy volunteers. Diagnostic performance of the automated MBF pixel maps was analyzed on patients using absolute MBF, myocardial perfusion reserve (MPR), and relative measurements of MBF and MPR.

Results

The correlation between automated and manual quantification was excellent (r = 0.96). Stress MBF and MPR in the ischemic zone were lower than those in the remote myocardium in patients with significant CAD (both p < 0.001). Stress MBF and MPR in the remote zone of the patients were lower than those in the normal volunteers (both p < 0.001). All quantitative metrics had good area under the curve (0.864 to 0.926), sensitivity (82.9% to 91.4%), and specificity (75.6% to 91.1%) on per-patient analysis. On a per-vessel analysis of the quantitative metrics, area under the curve (0.837 to 0.864), sensitivity (75.0% to 82.7%), and specificity (71.8% to 80.9%) were good.

Conclusions

Fully quantitative CMR MBF pixel maps can be generated automatically, and the results agree well with manual quantification. These methods can discriminate regional perfusion variations and have high diagnostic performance for detecting significant CAD. (Technical Development of Cardiovascular Magnetic Resonance Imaging; NCT00027170)  相似文献   

9.

Background

The local inflammatory tissue response after acute myocardial infarction (MI) determines subsequent healing. Systemic interaction may induce neuroinflammation as a precursor to neurodegeneration.

Objectives

This study sought to assess the influence of MI on cardiac and brain inflammation using noninvasive positron emission tomography (PET) of the heart-brain axis.

Methods

After coronary artery ligation or sham surgery, mice (n = 49) underwent serial whole-body PET imaging of the mitochondrial translocator protein (TSPO) as a marker of activated macrophages and microglia. Patients after acute MI (n = 3) were also compared to healthy controls (n = 9).

Results

Infarct mice exhibited elevated myocardial TSPO signal at 1 week versus sham (percent injected dose per gram: 8.0 ± 1.6 vs. 4.8 ± 0.9; p < 0.001), localized to activated CD68+ inflammatory cells in the infarct. Early TSPO signal predicted subsequent left ventricular remodeling at 8 weeks (rpartial = ?0.687; p = 0.001). In parallel, brain TSPO signal was elevated at 1 week (1.7 ± 0.2 vs. 1.4 ± 0.2 for sham; p = 0.017), localized to activated microglia. After interval decline at 4 weeks, progressive heart failure precipitated a second wave of neuroinflammation (1.8 ± 0.2; p = 0.005). TSPO was concurrently up-regulated in remote cardiomyocytes at 8 weeks (8.8 ± 1.7, p < 0.001) without inflammatory cell infiltration, suggesting mitochondrial impairment. Angiotensin-converting enzyme inhibitor treatment lowered acute inflammation in the heart (p = 0.003) and brain (p = 0.06) and improved late cardiac function (p = 0.05). Patients also demonstrated elevation of cardiac TSPO signal in the infarct territory, paralleled by neuroinflammation versus controls.

Conclusions

The brain is susceptible to acute MI and chronic heart failure. Immune activation may interconnect heart and brain dysfunction, a finding that provides a foundation for strategies to improve heart and brain outcomes.  相似文献   

10.

Background

Women with ST-segment elevation myocardial infarction (STEMI) receive suboptimal care and have worse outcomes than men. Whether strategies to reduce STEMI care variability impact disparities in the care and outcomes of women with STEMI is unknown.

Objectives

The study assessed the care and outcomes of men versus women with STEMI before and after implementation of a comprehensive STEMI protocol.

Methods

On July 15, 2014, the authors implemented: 1) emergency department catheterization lab activation; 2) STEMI Safe Handoff Checklist; 3) immediate transfer to an immediately available catheterization lab; and 4) radial first approach to percutaneous coronary intervention (PCI). The authors prospectively studied consecutive patients with STEMI and assessed guideline-directed medical therapy (GDMT) before PCI, median door-to-balloon time (D2BT), in-hospital adverse events, and 30-day mortality stratified by sex before (January 1, 2011 to July 14, 2014; control group) and after (July 15, 2014 to December 31, 2016) implementation of the STEMI protocol.

Results

Of 1,272 participants (68% men, 32% women), women were older with more comorbidities than men. In the control group, women had less GDMT (77% vs. 69%; p = 0.019) and longer D2BT (median 104 min; [interquartile range (IQR): 79 to 133] min vs. 112 [IQR: 85 to 147] min; p = 0.023). Women had more in-hospital stroke, vascular complications, bleeding, transfusion, and death. In the comprehensive 4-step STEMI protocol, sex disparities in GDMT (84% vs. 80%; p = 0.32), D2BT (89 [IQR: 68 to 106] min vs. 91 [IQR: 68 to 114] min; p = 0.15), and in-hospital adverse events resolved. The absolute sex difference in 30-day mortality decreased from the control group (6.1% higher in women; p = 0.002) to the comprehensive 4-step STEMI protocol (3.2% higher in women; p = 0.090).

Conclusions

A systems-based approach to STEMI care reduces sex disparities and improves STEMI care and outcomes in women.  相似文献   

11.

Background

Recent trials demonstrated a benefit of multivessel percutaneous coronary intervention (PCI) for noninfarct-related artery (non-IRA) stenosis over IRA-only PCI in patients with ST-segment elevation myocardial infarction (STEMI) multivessel disease. However, evidence is limited in patients with cardiogenic shock.

Objectives

This study investigated the prognostic impact of multivessel PCI in patients with STEMI multivessel disease presenting with cardiogenic shock, using the nationwide, multicenter, prospective KAMIR-NIH (Korea Acute Myocardial Infarction-National Institutes of Health) registry.

Methods

Among 13,104 consecutive patients enrolled in the KAMIR-NIH registry, we selected patients with STEMI with multivessel disease presenting with cardiogenic shock and who underwent primary PCI. Primary outcome was 1-year all-cause death, and secondary outcomes included patient-oriented composite outcome (a composite of all-cause death, any myocardial infarction, and any repeat revascularization) and its individual components.

Results

A total of 659 patients were treated by multivessel PCI (n = 260) or IRA-only PCI (n = 399) strategy. The risk of all-cause death and non-IRA repeat revascularization was significantly lower in the multivessel PCI group than in the IRA-only PCI group (21.3% vs. 31.7%; hazard ratio: 0.59; 95% confidence interval: 0.43 to 0.82; p = 0.001; and 6.7% vs. 8.2%; hazard ratio: 0.39; 95% confidence interval: 0.17 to 0.90; p = 0.028, respectively). Results were consistent after multivariable regression, propensity-score matching, and inverse probability weighting to adjust for baseline differences. In a multivariable model, multivessel PCI was independently associated with reduced risk of 1-year all-cause death and patient-oriented composite outcome.

Conclusions

Of patients with STEMI and multivessel disease with cardiogenic shock, multivessel PCI was associated with a significantly lower risk of all-cause death and non-IRA repeat revascularization. Our data suggest that multivessel PCI for complete revascularization is a reasonable strategy to improve outcomes in patients with STEMI with cardiogenic shock.  相似文献   

12.

Background

Novel cardiac magnetic resonance (CMR) stress T1 mapping can detect ischemia and myocardial blood volume changes without contrast agents and may be a more comprehensive ischemia biomarker than myocardial blood flow.

Objectives

This study describes the performance of the first prospective validation of stress T1 mapping against invasive coronary measurements for detecting obstructive epicardial coronary artery disease (CAD), defined by fractional flow reserve (FFR <0.8), and coronary microvascular dysfunction, defined by FFR ≥0.8 and the index of microcirculatory resistance (IMR ≥25 U), compared with first-pass perfusion imaging.

Methods

Ninety subjects (60 patients with angina; 30 healthy control subjects) underwent CMR (1.5- and 3-T) to assess left ventricular function (cine), ischemia (adenosine stress/rest T1 mapping and perfusion), and infarction (late gadolinium enhancement). FFR and IMR were assessed ≤7 days post-CMR. Stress and rest images were analyzed blinded to other information.

Results

Normal myocardial T1 reactivity (ΔT1) was 6.2 ± 0.4% (1.5-T) and 6.2 ± 1.3% (3-T). Ischemic viable myocardium downstream of obstructive CAD showed near-abolished T1 reactivity (ΔT1 = 0.7 ± 0.7%). Myocardium downstream of nonobstructive coronary arteries with microvascular dysfunction showed less-blunted T1 reactivity (ΔT1 = 3.0 ± 0.9%). Stress T1 mapping significantly outperformed gadolinium-based first-pass perfusion, including absolute quantification of myocardial blood flow, for detecting obstructive CAD (area under the receiver-operating characteristic curve: 0.97 ± 0.02 vs. 0.91 ± 0.03, respectively; p < 0.001). A ΔT1 of 1.5% accurately detected obstructive CAD (sensitivity: 93%; specificity: 95%; p < 0.001), whereas a less-blunted ΔT1 of 4.0% accurately detected microvascular dysfunction (area under the receiver-operating characteristic curve: 0.95 ± 0.03; sensitivity: 94%; specificity: 94%: p < 0.001).

Conclusions

CMR stress T1 mapping accurately detected and differentiated between obstructive epicardial CAD and microvascular dysfunction, without contrast agents or radiation.  相似文献   

13.

Objectives

This study sought to examine whether quality improvement initiatives across multiple ST-segment elevation myocardial infarction (STEMI) systems translated to faster first medical contact (FMC)-to-device times for patients presenting with cardiogenic shock (CS).

Background

There are limited data describing contemporary rates of achieving guideline-directed FMC-to-device times for STEMI patients with CS.

Methods

From 2012 to 2014, the American Heart Association Mission: Lifeline STEMI Systems Accelerator project established a protocol-guided approach to STEMI reperfusion systems in 484 U.S. hospitals. The study was stratified by CS versus no CS at presentation and performed Cochrane-Armitage tests to evaluate trends of achieving FMC-to-device time targets. A multivariable logistic regression model assessed the association between achieving guideline-directed FMC-to-device times and mortality.

Results

Among 23,785 STEMI patients, 1,993 (8.4%) experienced CS at presentation. For direct presenters, patients with CS were less likely to achieve the 90-min FMC-to-device time compared with no-CS patients (37% vs. 54%; p < 0.001). For transferred patients, CS patients were even less likely to reach the 120-min FMC-to-device time compared with no-CS patients (34% vs. 47%; p < 0.0001). The Accelerator intervention did not result in improvements in the FMC-to-device times for direct-presenting CS patients (p for trend = 0.53), although there was an improvement for transferred patients (p for trend = 0.04). Direct-presenting patients arriving within 90 min had lower mortality rates compared with patients who reached after 90 min (20.49% vs. 39.12%; p < 0.001).

Conclusions

Fewer than 40% of STEMI patients presenting with CS achieved guideline-directed FMC-to-device targets; delays in reperfusion for direct-presenting patients were associated with higher mortality.  相似文献   

14.

Objectives

This study assessed diffuse myocardial fibrosis (MF) by cardiac magnetic resonance (CMR) imaging and speckle-tracking echocardiography (STE) in patients with severe aortic stenosis (AS) and validated findings by using histologic confirmation of MF.

Background

MF is a concomitant pathologic finding related to hypertrophic response in severe AS. It would be beneficial to have reliable imaging methods to assess MF.

Methods

CMR and STE were performed in 71 consecutive patients with severe AS before aortic valve replacement. The extracellular volume (ECV) and native T1 values obtained by CMR and global longitudinal strain (GLS) values by STE were measured. The degree of MF was quantified by using Masson trichrome stain in myocardial biopsy specimens obtained intraoperatively. The study population was divided into 3 groups according to the degree of MF on histology (mild, moderate, and severe MF).

Results

The severe MF group had a higher incidence of heart failure (HF) and diastolic dysfunction than the mild and moderate MF groups. The ECV (r = 0.465; p < 0.0001), GLS (r = 0.421; p = 0.0003), and native T1 (r = 0.429; p = 0.0002) values were significantly correlated with the degree of MF. GLS was moderately correlated with ECV (r = 0.455; p = 0.0001) and less with the native T1 (r = 0.372; p = 0.0014) value. The model using ECV (R2 = 0.44; Akaike Information Criterion [AIC] = 55.8) was found to predict the degree of MF most accurately than that with GLS (R2 = 0.35; AIC = 66.84) and the native T1 (R2 = 0.36; AIC = 66.18) value. The secondary endpoint of interest was clinical outcome of a composite of total mortality, admission for HF, or development of HF symptoms. During follow-up (median: 4.6 years), and there were 16 clinical events. Although statistically insignificant, ECV is more closely related to prediction of the clinical outcome than native T1 or GLS.

Conclusions

ECV as assessed by CMR could be an ideal surrogate marker for diffuse MF in patients with severe AS among all 3 models considered.  相似文献   

15.

Objectives

This study sought to determine whether T2 cardiac magnetic resonance (CMR) can stage both hemorrhagic and nonhemorrhagic myocardial infarctions (MIs).

Background

CMR-based staging of MI with or without contrast agents relies on the resolution of T2 elevations in the chronic phase, but whether this approach can be used to stage both hemorrhagic and nonhemorrhagic MIs is unclear.

Methods

Hemorrhagic (n = 15) and nonhemorrhagic (n = 9) MIs were created in dogs. Multiparametric noncontrast mapping (T1, T2, and T2*) and late gadolinium enhancement (LGE) were performed at 1.5- and 3.0-T at 5 days (acute) and 8 weeks (chronic) post-MI. CMR relaxation values and LGE intensities of hemorrhagic, peri-hemorrhagic, nonhemorrhagic, and remote territories were measured. Histopathology was performed to elucidate CMR findings.

Results

T2 of nonhemorrhagic MIs was significantly elevated in the acute phase relative to remote territories (1.5-T: 39.8 ± 12.8%; 3.0-T: 27.9 ± 16.5%; p < 0.0001 for both) but resolved to remote values by week 8 (1.5-T: ?0.0 ± 3.2%; p = 0.678; 3.0-T: ?0.5 ± 5.9%; p = 0.601). In hemorrhagic MI, T2 of hemorrhage core was significantly elevated in the acute phase (1.5-T: 17.7 ± 10.0%; 3.0-T: 8.6 ± 8.2%; p < 0.0001 for both) but decreased below remote values by week 8 (1.5-T: ?8.2 ± 3.9%; 3.0-T: ?5.6 ± 6.0%; p < 0.0001 for both). In contrast, T2 of the periphery of hemorrhage within the MI zone was significantly elevated in the acute phase relative to remote territories (1.5-T: 35.0 ± 16.1%; 3.0-T: 24.2 ± 10.4%; p < 0.0001 for both) and remained elevated at 8 weeks post-MI (1.5-T: 8.6 ± 5.1%; 3.0-T: 6.0 ± 3.3%; p < 0.0001 for both). The observed elevation of T2 in the peri-hemorrhagic zone of MIs and the absence of T2 elevation in nonhemorrhagic MIs were consistent with ongoing or absence of histological evidence of inflammation, respectively.

Conclusions

Hemorrhagic MIs are associated with persisting myocardial inflammation and edema, which can confound staging of hemorrhagic MIs when T2 elevations alone are used to discriminate between acute and chronic MI. Moreover, given the poor prognosis in patients with hemorrhagic MI, CMR evidence for myocardial hemorrhage with persistent edema may evolve as a risk marker in patients after acute MI.  相似文献   

16.

Background

Coronary artery disease (CAD) remains the major cause of cardiac morbidity and mortality worldwide, despite the advances in treatment with coronary revascularization and modern antiremodeling therapy. Risk stratification in CAD patients is primarily based on left ventricular volumes, ejection fraction (LVEF), risk scores, and the presence and extent of late gadolinium enhancement (LGE). The prognostic role of T1 mapping in noninfarcted myocardium in CAD patients has not yet been determined.

Objectives

This study sought to examine prognostic significance of native T1 mapping of noninfarcted myocardium in patients with CAD.

Methods

A prospective, observational, multicenter longitudinal study of consecutive patients undergoing routine cardiac magnetic resonance imaging with T1 mapping and LGE. The primary endpoint was all-cause mortality. Major adverse cardiocerebrovascular events (MACCE) (cardiac mortality, nonfatal acute coronary syndrome, stroke, and appropriate device discharge) are also reported.

Results

A total of 34 deaths and 71 MACCE (n = 665, males n = 424, median age [interquartile range] 57 [22] years; 64%; median follow-up period of 17 [11] months) were observed. Native T1 and extracellular volume were univariate predictors of outcome. Native T1 and LGE were stronger predictors of survival and MACCE compared with extracellular volume, LVEF, cardiac volumes, and clinical scores (p < 0.001). Native T1 of noninfarcted myocardium was the sole independent predictor of all-cause mortality (chi-square = 21.7; p < 0.001), which was accentuated in the absence of LGE or LVEF ≤35%. For MACCE, native T1 and LGE extent were joint independent predictors (chi-square = 25.6; p < 0.001).

Conclusions

Characterization of noninfarcted myocardium by native T1 is an important predictor of outcome in CAD patients, over and above the traditional risk stratifiers. The current study’s results provide a basis for a novel risk stratification model in CAD based on a complementary assessment of noninfarcted myocardium and post-infarction scar, by native T1 mapping and LGE, respectively.  相似文献   

17.

Objectives

This study introduced and validated a novel flow-independent delayed enhancement technique that shows hyperenhanced myocardium while simultaneously suppressing blood-pool signal.

Background

The diagnosis and assessment of myocardial infarction (MI) is crucial in determining clinical management and prognosis. Although delayed enhancement cardiac magnetic resonance (DE-CMR) is an in vivo reference standard for imaging MI, an important limitation is poor delineation between hyperenhanced myocardium and bright LV cavity blood-pool, which may cause many infarcts to become invisible.

Methods

A canine model with pathology as the reference standard was used for validation (n = 22). Patients with MI and normal controls were studied to ascertain clinical performance (n = 31).

Results

In canines, the flow-independent dark-blood delayed enhancement (FIDDLE) technique was superior to conventional DE-CMR for the detection of MI, with higher sensitivity (96% vs. 85%, respectively; p = 0.002) and accuracy (95% vs. 87%, respectively; p = 0.01) and with similar specificity (92% vs, 92%, respectively; p = 1.0). In infarcts that were identified by both techniques, the entire length of the endocardial border between infarcted myocardium and adjacent blood-pool was visualized in 33% for DE-CMR compared with 100% for FIDDLE. There was better agreement for FIDDLE-measured infarct size than for DE-CMR infarct size (95% limits-of-agreement, 2.1% vs. 5.5%, respectively; p < 0.0001). In patients, findings were similar. FIDDLE demonstrated higher accuracy for diagnosis of MI than DE-CMR (100% [95% confidence interval [CI]: 89% to 100%] vs. 84% [95% CI: 66% to 95%], respectively; p = 0.03).

Conclusions

The study introduced and validated a novel CMR technique that improves the discrimination of the border between infarcted myocardium and adjacent blood-pool. This dark-blood technique provides diagnostic performance that is superior to that of the current in vivo reference standard for the imaging diagnosis of MI.  相似文献   

18.

Background

In patients with angina and nonobstructive coronary artery disease (NOCAD), confirming symptoms due to coronary microvascular dysfunction (CMD) remains challenging. Cardiac magnetic resonance (CMR) assesses myocardial perfusion with high spatial resolution and is widely used for diagnosing obstructive coronary artery disease (CAD).

Objectives

The goal of this study was to validate CMR for diagnosing microvascular angina in patients with NOCAD, compared with patients with obstructive CAD and correlated to the index of microcirculatory resistance (IMR) during invasive coronary angiography.

Methods

Fifty patients with angina (65 ± 9 years of age) and 20 age-matched healthy control subjects underwent adenosine stress CMR (1.5- and 3-T) to assess left ventricular function, inducible ischemia (myocardial perfusion reserve index [MPRI]; myocardial blood flow [MBF]), and infarction (late gadolinium enhancement). During subsequent angiography within 7 days, 28 patients had obstructive CAD (fractional flow reserve [FFR] ≤0.8) and 22 patients had NOCAD (FFR >0.8) who underwent 3-vessel IMR measurements.

Results

In patients with NOCAD, myocardium with IMR <25 U had normal MPRI (1.9 ± 0.4 vs. controls 2.0 ± 0.3; p = 0.49); myocardium with IMR ≥25 U had significantly impaired MPRI, similar to ischemic myocardium downstream of obstructive CAD (1.2 ± 0.3 vs. 1.2 ± 0.4; p = 0.61). An MPRI of 1.4 accurately detected impaired perfusion related to CMD (IMR ≥25 U; FFR >0.8) (area under the curve: 0.90; specificity: 95%; sensitivity: 89%; p < 0.001). Impaired MPRI in patients with NOCAD was driven by impaired augmentation of MBF during stress, with normal resting MBF. Myocardium with FFR >0.8 and normal IMR (<25 U) still had blunted stress MBF, suggesting mild CMD, which was distinguishable from control subjects by using a stress MBF threshold of 2.3 ml/min/g with 100% positive predictive value.

Conclusions

In angina patients with NOCAD, CMR can objectively and noninvasively assess microvascular angina. A CMR-based combined diagnostic pathway for both epicardial and microvascular CAD deserves further clinical validation.  相似文献   

19.

Objectives

This study sought to evaluate the prognostic usefulness of visual and quantitative perfusion cardiac magnetic resonance (CMR) ischemic burden in an unselected group of patients and to assess the validity of consensus-based ischemic burden thresholds extrapolated from nuclear studies.

Background

There are limited data on the prognostic value of assessing myocardial ischemic burden by CMR, and there are none using quantitative perfusion analysis.

Methods

Patients with suspected coronary artery disease referred for adenosine-stress perfusion CMR were included (n = 395; 70% male; age 58 ± 13 years). The primary endpoint was a composite of cardiovascular death, nonfatal myocardial infarction, aborted sudden death, and revascularization after 90 days. Perfusion scans were assessed visually and with quantitative analysis. Cross-validated Cox regression analysis and net reclassification improvement were used to assess the incremental prognostic value of visual or quantitative perfusion analysis over a baseline clinical model, initially as continuous covariates, then using accepted thresholds of ≥2 segments or ≥10% myocardium.

Results

After a median 460 days (interquartile range: 190 to 869 days) follow-up, 52 patients reached the primary endpoint. At 2 years, the addition of ischemic burden was found to increase prognostic value over a baseline model of age, sex, and late gadolinium enhancement (baseline model area under the curve [AUC]: 0.75; visual AUC: 0.84; quantitative AUC: 0.85). Dichotomized quantitative ischemic burden performed better than visual assessment (net reclassification improvement 0.043 vs. 0.003 against baseline model).

Conclusions

This study was the first to address the prognostic benefit of quantitative analysis of perfusion CMR and to support the use of consensus-based ischemic burden thresholds by perfusion CMR for prognostic evaluation of patients with suspected coronary artery disease. Quantitative analysis provided incremental prognostic value to visual assessment and established risk factors, potentially representing an important step forward in the translation of quantitative CMR perfusion analysis to the clinical setting.  相似文献   

20.

Objectives

This study investigated the prevalence of silent myocardial infarction (MI) in patients presenting with first acute myocardial infarction (AMI), and its relation with mortality and major adverse cardiovascular events (MACE) at long-term follow-up.

Background

Up to 54% of MI occurs without apparent symptoms. The prevalence and long-term prognostic implications of previous silent MI in patients presenting with seemingly first AMI are unclear.

Methods

A 2-center observational longitudinal study was performed in 392 patients presenting with first AMI between 2003 and 2013, who underwent late gadolinium enhancement cardiac magnetic resonance (LGE-CMR) examination within 14 days post-AMI. Silent MI was assessed on LGE-CMR images by identifying regions of hyperenhancement with an ischemic distribution pattern in other territories than the AMI. Mortality and MACE (all-cause death, reinfarction, coronary artery bypass grafting, and ischemic stroke) were assessed at 6.8 ± 2.9 years follow-up.

Results

Thirty-two patients (8.2%) showed silent MI on LGE-CMR. Compared with patients without silent MI, mortality risk was higher in patients with silent MI (hazard ratio: 3.87; 95% confidence interval: 1.21 to 12.38; p = 0.023), as was risk of MACE (hazard ratio: 3.10; 95% confidence interval: 1.22 to 7.86; p = 0.017), both independent from clinical and infarction-related characteristics.

Conclusions

Silent MI occurred in 8.2% of patients presenting with first AMI and was independently related to poorer long-term clinical outcome, with a more than 3-fold risk of mortality and MACE. Silent MI holds prognostic value over important traditional prognosticators in the setting of AMI, indicating that these patients represent a high-risk subgroup warranting clinical awareness.  相似文献   

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