Prognostic Value and Determinants of CMR-Derived Left Atrial Function Assessed in STEMI

Left atrial and ventricular longitudinal strain by cardiac magnetic resonance feature tracking improves prognostic stratification of patients with ST-segment elevation myocardial infarction

We aimed to investigate the predictive value of left atrium (LA) and left ventricle (LV) longitudinal strain derived by CMR-FT early after ST-segment elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (pPCI). Patients with STEMI who received pPCI and completed CMR within the following week were enrolled. LA and LV longitudinal strain parameters were derived from cine CMR by FT; conventional CMR indexes were also performed. The primary endpoint was the occurrence of major cardiovascular adverse events (MACE), defined as a composite of death, reinfarction, and congestive heart failure (HF). 276 participants (median age, 57 years, IQR, 48-66 years; 85% men) were included in this study. CMR was usually completed on the 5 (IQR,4-7) days after pPCI. During a median follow-up of 16 months, MACE occurred in 35 (12.7%) participants. Multivariable Cox regression analysis showed that LA conduit strain (HR 0.91, 95%CI: 0.84, 0.98, p = 0.013) and LV global longitudinal strain (HR 1.17, 95%CI: 1.03, 1.34, p = 0.016) remained independently associated with MACE. Participants with impaired LA conduit strain (≤ 12.8%) and LV global longitudinal strain (> -13.1%) had a higher risk of MACE than those with preserved. Longitudinal strain of LA and LV could provide independent prognostic information in STEMI patients, and comprehensive assessment of Left atrial and ventricular longitudinal strain significantly improved the prognosis.

Diagnostic accuracy of left atrial function and strain for differentiating between acute and chronic myocardial infarction

BACKGROUND

The cardiac magnetic resonance tissue tracking (CMR-TT) technique was used to obtain left atrial strain and strain rate in patients with myocardial infarction (MI) and to evaluate the utility of this technique in the quantitative assessment of myocardial infarction for distinguishing acute from chronic myocardial infarction.

METHODS

We retrospectively analyzed 36 consecutive patients with acute myocardial infarction (AMI) and 29 patients with chronic myocardial infarction (CMI) who underwent CMR and 30 controls. Left atrial (LA) and ventricular functions were quantified by volumetric, and CMR-TT derived strain analysis from long and short left ventricular view cines. Receiver Operating Characteristics (ROC) analysis was used to determine the diagnostic accuracy of CMR-TT strain parameters for discriminating between acute and chronic myocardial infarction.

RESULTS

AMI and CMI participants had impaired LA reservoir function, conduit function and LA booster pump dysfunction compared to the controls. LA strain was more sensitive than LV global strain for the assessment of the MI stage. Peak late-negative SR yielded the best areas under the ROC curve (AUC) of 0.879, showing differentiation between acute and chronic myocardial infarction of all the LA strain parameters obtained. The highest significant differences between chronic myocardial infarction and normal myocardium were also found in the LV strain (p < 0.001) and LA functional parameters (p < 0.001), but there was no difference between AMI and normals.

CONCLUSIONS

CMR-TT-derived LA strain is a potential and robust tool in demonstrating impaired LA mechanics and quantifying LA dynamics, which have high sensitivity and specificity in the differential diagnosis of acute versus chronic myocardial infarction. Their use is thus worth popularizing in clinical application.

Predictive value of myocardial strain on myocardial infarction size by cardiac magnetic resonance imaging in ST-segment elevation myocardial infarction with preserved left ventricular ejection fraction

Background: The correlation between myocardial strain and infraction size by cardiac magnetic resonance imaging in ST-segment elevation myocardial infarction (STEMI) with preserved left ventricular ejection fraction (LVEF) is not clear.

Objective: To investigate the correlation between myocardial strain and myocardial infarction size in patients of acute STEMI with preserved LVEF.

Materials and Methods: A retrospective study was conducted to assess 31 patients with acute ST-segment elevation myocardial infarction (STEMI)after primary percutaneous coronary intervention (PCI) who received cardiac magnetic resonance (CMR) imaging during hospitalization at the Central Hospital of Shandong First Medical University from 2019 to 2022 and whose echocardiography indicated preserved LVEF (LVEF≥50%). The control group consisted of 21 healthy adults who underwent CMR during the same period. We compared the CMR characteristics, global and segmental strain between the two groups. Furthermore, the correlation between the global strain and the segmental strain of the left ventricle and late gadolinium enhancement (LGE) were evaluated.

Results: Compared with healthy controls, the left ventricular ejection fraction (LVEF) of STEMI patients with preserved LVEF was significantly decreased (p < 0.05). Moreover, the global radial strain (GRS) (24.09% [IQR:17.88–29.60%] vs. 39.56% [IQR:29.19–42.20%], p < 0.05), global circumferential strain (GCS) [−14.66% (IQR: 17.91–11.56%) vs. −19.26% (IQR: 21.03–17.73%), p < 0.05], and global longitudinal strains (GLS) (−8.88 ± 2.25% vs. −13.46 ± 2.63%, p < 0.05) were damaged in patients. Furthermore, GCS and GLS were associated with LGE size (%left ventricle) (GCS: r = 0.58, p < 0.05; GLS: r = 0.37, p < 0.05). In the multivariate model, we found that LGE size was significantly associated with GCS (β coefficient = 2.110, p = 0.016) but was not associated with GLS (β coefficient = −0.102, p = 0.900) and LVEF (β coefficient = 0.227, p = 0.354). The receiver operating characteristic (ROC) results showed that GCS emerged as the strongest LGE size (LGE >25%) prognosticator among strain parameters (AUC: 0.836 [95% CI, 0.692—0.981], sensitivity: 91%, specificity: 80%) and was significantly better (p = 0.001) than GLS [AUC: 0.761 (95% CI, 0.583—0.939), sensitivity: 64%, specificity: 85%] and LVEF [AUC: 0.673 (95% CI, 0.469—0.877), sensitivity: 73%, specificity: 70%].

Conclusion: Among STEMI patients with preserved LVEF after PCI, CMR-FT-derived GCS had superior diagnostic accuracy than GLS and LVEF in predicting myocardial infarction size.

Cardiac magnetic resonance derived left atrial strain after ST-elevation myocardial infarction: an independent prognostic indicator

Background

The prognostic value of cardiac magnetic resonance (CMR) derived left atrial (LA) strain, ejection fraction (LAEF) and indexed volumes (LAVI_max and LAVI_min) after ST-elevation myocardial infarction (STEMI) remains controversial. The aim of this study was to assess the relationship between LA function and major adverse cardiovascular events (MACE) after STEMI.

Methods

A total of 202 prospectively recruited patients who underwent CMR at median day 4 after STEMI had complete CMR data for feature tracking assessment. LA reservoir and booster strain were quantified based on the average of three independently repeated measurements.

Results

MACE occurred in 35 patients during a median follow up of 607 days. Patients with MACE had lower median LA reservoir strain (18.9% vs. 29.4%, P<0.001), LA booster strain (9.4% vs. 13.0%, P=0.002) and LAEF (41.5% vs. 49.2%, P<0.001) than patients without MACE. Kaplan-Meier analyses demonstrated a difference in MACE between high- and low-risk groups for LA reservoir strain (cutoff 19.2%, P<0.001), LA booster strain (cutoff 9.7%, P<0.001) and LAEF (cutoff 38.5%, P<0.001). The AUC increased from 0.713 (95% CI: 0.608-0.818) for LVEF to 0.775 (95% CI: 0.680-0.870) when LA reservoir strain was added to LVEF (P=0.047). Univariate Cox regression analysis showed that all LA parameters had a significant effect on MACE, while multivariate analysis found LA reservoir strain was an independent predictor of MACE (HR 0.905; 95% CI: 0.843-0.972, P=0.006).

Conclusions

CMR derived LA reservoir strain independently predicted MACE after STEMI when adjusted for standard risk measures.

Role of Cardiac Magnetic Resonance to Improve Risk Prediction Following Acute ST-Elevation Myocardial Infarction

Cardiac magnetic resonance (CMR) imaging allows comprehensive assessment of myocardial function and tissue characterization in a single examination after acute ST-elevation myocardial infarction. Markers of myocardial infarct severity determined by CMR imaging, especially infarct size and microvascular obstruction, strongly predict recurrent cardiovascular events and mortality. The prognostic information provided by a comprehensive CMR analysis is incremental to conventional risk factors including left ventricular ejection fraction. As such, CMR parameters of myocardial tissue damage are increasingly recognized for optimized risk stratification to further ameliorate the burden of recurrent cardiovascular events in this population. In this review, we provide an overview of the current impact of CMR imaging on optimized risk assessment soon after acute ST-elevation myocardial infarction.

Left Atrial Function with MRI Enables Prediction of Cardiovascular Events after Myocardial Infarction: Insights from the AIDA STEMI and TATORT NSTEMI Trials

Background The role of left atrial (LA) performance in acute myocardial infarction (AMI) remains controversial. Cardiac MRI myocardial feature tracking (hereafter, MRI-FT) is a method used to quantify myocardial function that enables reliable assessment of atrial function. Purpose To assess the relationship between LA function assessed with MRI-FT and major adverse cardiovascular events (MACE) after AMI. Materials and Methods This secondary analysis of two prospective multicenter cardiac MRI studies (AIDA STEMI [NCT00712101] and TATORT NSTEMI [NCT01612312]) included 1235 study participants with ST-elevation myocardial infarction (n = 795) or non-ST-elevation myocardial infarction (n = 440) between July 2008 and June 2013. All study participants underwent primary percutaneous coronary intervention. MRI-FT analyses were performed in a core laboratory by researchers blinded to clinical status to determine LA performance using LA reservoir function peak systolic strain (εs), LA conduit strain (εe), and LA booster pump function active strain (εa). The relationship of LA performance to a MACE within 12 months after AMI was evaluated by using Cox proportional hazards models and area under the receiver operating characteristic curve (AUC). Results Study participants with MACE had worse LA performance parameters compared with study participants without MACE (εs = 21.2% vs 16.2%, εe = 8.8% vs 6.9%, εa = 11.8% vs 10%; P < .001 for all). All atrial parameters were strongly associated with MACE (hazard ratio [HR], εs = 0.9, εe = 0.88, εa = 0.89; P < .001 for all). For εs, a cutoff of 18.8% was identified as the only independent atrial parameter with which to predict MACE after accounting for confounders and established prognostic markers in adjusted analysis (HR, 0.95; P = .02). The εs yielded incremental prognostic value above left ventricular ejection fraction, global longitudinal strain, microvascular obstruction, and infarct size (AUC comparisons, P < .04 for all). Conclusion Feature tracking of cardiac MRI to derive left atrial peak reservoir strain provided incremental prognostic value for major adverse cardiovascular events prediction versus established cardiac risk factors after acute myocardial infarction. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Almeida in this issue.