What is the clinical evidence from this study?

Study design: Cohort. Population: Acute myocardial infarction (n=487). Intervention: Indexed left atrial volume (LAVi) assessment vs. Normal left atrial volume. Primary outcome: All-cause mortality and major adverse cardiac events (MACE) per 10 mL/m2 increase in LAVi (HR 1.21, 95% CI 1.05-1.38, p=0.006).

October 21, 2024Echo Research and Practice9 citationsOpen Access

Left atrial volume assessed by echocardiography identifies patients with high risk of adverse outcome after acute myocardial infarction

Q: What does this research mean for the field?

Indexed left atrial volume independently predicts all-cause mortality and major adverse cardiac events after acute myocardial infarction, with a 21% higher risk per 10 mL/m2 increase. Novelty: ClaimNovelty.CONFIRMATORY. Consensus alignment: ConsensusAlignment.NEUTRAL.

JTJorun TangenOslo University Hospital TNThuy Mi NguyenOslo University Hospital DMDaniela MelichovaCardiac Imaging

Key Result

Indexed left atrial volume independently predicted all-cause mortality and major adverse cardiac events after acute myocardial infarction, with a 21% higher risk per 10 mL/m2 increase.

Study Design

Type

Cohort (n=487)

Multicenter

Yes

Structured PICO

Does increased indexed left atrial volume (LAVi) predict all-cause mortality and MACE in patients with acute myocardial infarction despite contemporary treatment strategies?

Population

n=487 patients with acute myocardial infarction (93% NSTEMI, 7% STEMI), mean age 69 ± 12 years, 26.2% female, enrolled across three hospitals in Norway. Key inclusion: post-PCI on the day of hospital discharge. Key exclusion: type 2 infarction and other causes of chest pain.

Intervention

Assessment of indexed left atrial volume (LAVi) by transthoracic echocardiography within 48 hours after myocardial infarction, evaluated as a continuous variable and dichotomized as enlarged (>34 mL/m2).

Comparator

Normal indexed left atrial volume (LAVi ≤34 mL/m2) or lower LAVi values (when evaluated as a continuous variable).

Outcome

Composite of all-cause mortality and major adverse cardiac events (MACE: defined as hospital readmission due to myocardial infarction, cardiac arrest, stroke, heart failure, or onset of new atrial fibrillation) at a median follow-up of 3.8 years.composite

Indexed left atrial volume assessed by echocardiography remains a strong, independent predictor of mortality and MACE in patients with acute myocardial infarction, even in the era of contemporary revascularization and medical therapies.

Main Result

Effect estimate: HR 1.21 (95% CI 1.05-1.38)

p-value: p=0.006

Limitations

Echocardiography was performed within the initial 48 hours before the full left ventricular remodeling process was complete.
Left atrial volume was measured using two-dimensional rather than more accurate three-dimensional imaging.
Non-consecutive enrollment process and daytime physician availability may introduce selection bias.
High proportion of revascularized patients (92.0%) due to exclusion of type 2 myocardial infarction limits generalizability.

Abstract

Abstract Background The left atrial (LA) volume has been demonstrated to be an important predictor of adverse outcome in patients with various cardiac conditions, including acute myocardial infarction (AMI). However, new treatment strategies in patients with AMI have led to better patient outcomes. We hypothesised that increased LA size could still predict mortality in patients with AMI despite improved treatment strategies. Methods We included patients with AMI in a prospective multicenter cohort study and the study patients were enrolled from 2014 to 2022. We recorded echocardiographic and clinical data during their index hospitalisation. Indexed LA volume (LAVi) was assessed in all patients and was used as a continuous variable in the univariate and multivariate Cox regression analysis. The study took place over a period of five years and median follow-up time was 3.8 years (range 3.1 to 5.0 years). The primary study outcomes were all-cause mortality and major adverse cardiac events (MACE). MACE was defined as hospital readmission due to myocardial infarction, cardiac arrest, stroke, heart failure, or onset of new atrial fibrillation. Results We included 487 patients (69 ± 12 years old, 26% female) with AMI. During the follow-up period all-cause mortality was 50 (10.3%) and patients who reached the primary outcomes were 153 (31.4%). The deceased patients had higher LAVi compared to survivors (40.0 ± 12.9 mL/m 2 vs. 29.7 ± 11.2 mL/m 2 , p < 0.001). Factors associated with all-cause mortality and MACE were age, year of enrollment, left ventricular (LV) ejection fraction, LV global longitudinal strain (GLS), LV filling pressure, moderate or severe mitral regurgitation and LAVi. GLS and EF were segregated into two distinct models due to their moderately high correlation ( r = 0.57, p < 0.001). LAVi remained as an independent echocardiographic predictor of primary outcomes after adjusting for the covariates above in two separates multivariable Cox regression models (hazard ratio 1.02/1.02 mL/m 2 95% CI 1.01–1.03/1.01–1.03, p = 0.006/0.003). Conclusions Our study demonstrated that LA dilatation is an independent echocardiographic predictor of mortality and MACE in patients with AMI despite improved treatment strategies. This finding highlights the potential of using LAVi as a marker for prognostication in these patients.

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