Prognostic value of a left atrioventricular coupling index in pre- and post-menopausal women from the Multi-Ethnic Study of Atherosclerosis

Left atrial remodelling and function in various left ventricular hypertrophic phenotypes

AIMS

How the underlying aetiology and pathophysiology of left ventricular (LV) hypertrophy affects left atrial (LA) remodelling and function remains unexplored. The present study aims to investigate the influence of various hypertrophic phenotypes on LA remodelling and function.

METHODS AND RESULTS

Patients with LV hypertrophy who underwent cardiac magnetic resonance (CMR) were compared to a control group. CMR data were analysed retrospectively to assess LA strain, volume, sphericity, and left atrioventricular coupling index (LACI). Independent clinical associates of LA strain were assessed using multivariable linear regression analysis. A total of 375 individuals were included: 148 with hypertrophic cardiomyopathy (HCM), 35 with cardiac amyloidosis (CA), 41 with hypertensive (HTN) heart disease, 97 with severe asymptomatic aortic stenosis (AS), and 54 with normal CMR. Indexed LA end-systolic (iLVmax), diastolic volumes, and LA sphericity were the largest in patients with CA (59.1 ± 16.9 mL/m2, 46.8 ± 16.4 mL/m2, and 83.2 ± 2.1%, respectively). Patients with CA presented a higher LACI when compared with other groups (58 ± 2% vs. 42 ± 2% in HCM, 39 ± 2% in HTN heart disease, 37 ± 2% in AS, and 22 ± 1% in normal), while no differences were observed across others. Patients with CA showed the lowest LA reservoir [9.6% (0.6-18.6%)] and booster strain (9.1 ± 5.4%), whereas no differences were observed across other groups. LACI and iLAVmax were independently correlated with LA reservoir (β = 0.15 and β = -39.33, respectively), LA conduit (β = 0.08 and β = -17.08, respectively), and LA booster strains (β = 0.1 and β = -28.69, respectively). LA sphericity was independently correlated with LA reservoir strain (β = -0.51). Finally, LV global longitudinal strain was independently correlated with LA reservoir (β = -0.43), conduit (β = -0.20), and booster strain (β = -0.24).

CONCLUSION

LA characteristics differ among LV hypertrophic phenotypes. LACI and iLAVmax are independently correlated with LA function, while LA sphericity correlates independently with LA reservoir strain.

The power of the left atrioventricular coupling index in cardiovascular disease

The left atrioventricular coupling index (LACI) has emerged as a novel and transformative biomarker in cardiovascular research, addressing long-standing limitations in traditional cardiac function assessments. By quantifying the ratio of left atrial to left ventricular end-diastolic volumes, LACI offers unprecedented prognostic insights into a wide range of cardiovascular diseases, including atrial fibrillation, heart failure, and myocardial infarction, as well as other conditions such as hypertension and cardiomyopathies. Recent evidence highlights its unique ability to integrate atrial and ventricular dynamics, offering a more comprehensive perspective on cardiac health and disease progression. This review synthesizes the latest advancements in LACI research, elucidates its underlying pathophysiological mechanisms, and explores its expanding clinical applications as a pivotal tool for risk stratification, precision diagnostics, and personalized therapy in cardiovascular medicine.

Prognostic value of left atrioventricular coupling index in heart failure

AIMS

To investigate the distribution of left atrioventricular coupling index (LACI) among patients with heart failure and left ventricular ejection fraction (LVEF) < 50% and to explore its association with the combined endpoint of all-cause death or HF hospitalization at long-term follow-up.

METHODS AND RESULTS

Patients with HF and LVEF < 50% undergoing cardiac magnetic resonance were evaluated. Patients with atrial fibrillation or flutter were excluded. Left atrioventricular coupling index was measured as the ratio between the left atrial (LA) and the LV end-diastolic volumes. Patient population was divided according to LACI tertiles and followed up. Total of 478 patients (mean age 62 ± 12 years, 78% male) were included. The median value of LACI was 27.1% (interquartile range 19.9-34.5). Patients within the worst LACI tertile (≥30.9%) showed smaller LV volumes and larger LA volumes as compared with patients in the first or second tertile (LACI 6.2-22.2 and LACI 22.3-30.9, respectively). Left atrioventricular coupling index was significantly associated with the combined endpoint [hazard ratio (HR) 1.87, P = 0.01]. After adjusting for sex, age, ischaemic HF aetiology, LVEF, LA reservoir strain, diabetes mellitus, LV scar, mitral regurgitation, and LVEDVi, LACI remained significantly associated with the combined endpoint (HR 1.77, P = 0.02). Patients with the highest LACI values had worse outcomes compared with patients in first and second tertiles (HR 1.69, P = 0.02 and HR 1.77, P = 0.02, respectively).

CONCLUSION

In patients with HF and LVEF <50%, LACI is independently associated with adverse events. Patients with most impaired left atrioventricular coupling have the worst clinical outcomes.

The Possibilities and Importance of Assessing the Left Atrioventricular Coupling Index Using Various Diagnostic Imaging Methods in an Adult Population: A Comprehensive Review

Cardiovascular diseases are a leading cause of death worldwide, and they are becoming even more frequent due to the aging of society. Due to this fact, new parameters that are useful in diagnosing, as well as in assessing, the risk of cardiovascular events, and in future prognosis estimation, should be developed. The left atrioventricular coupling index (LACI) has been recently introduced as the one parameter meeting these criteria. The current review aims to collect all available data and assess whether the LACI may be a valuable tool in daily clinical practice, and, simultaneously, to direct future research on the subject. The LACI is a parameter that can be calculated based on echocardiographic, cardiac CT and CMR examinations. It appears to be of use in several cardiovascular diseases, especially heart failure and atrial fibrillation, both in diagnostics and as a prognostic marker. Moreover, the LACI is a useful marker in cardiomyopathies, myocardial infarction, beta-thalassemia major and light-chain amyloidosis. However, the number of studies on the subject of LACI is limited, and some of these studies are based on the same cohort of patients. Future studies should take up the subject of the LACI, especially when it comes to the value of calculating the LACI based on various imaging techniques, including echocardiography.

A novel index evaluating left atrioventricular coupling function in chronic kidney disease with diabetes patients

The left atrioventricular coupling index (LACI) evaluates the coupling function between the left atrial (LA) and left ventricular (LV) chambers. However, little is known about LACI in chronic kidney disease (CKD) patients. This study aimed to assess the impact of concurrent CKD and type 2 diabetes mellitus (T2DM) on left atrioventricular coupling function compared to CKD patients without T2DM. A retrospective analysis included 173 CKD 4-5 stage patients who underwent echocardiographic examinations. The study comprised 75 CKD patients with T2DM (CKD + DM) and 98 CKD patients without T2DM (CKD-DM). During the follow-up, major adverse cardiac events (MACE) were tracked until June 30, 2024, or death, with a median duration of 21 (18, 27) months, 20.8% of patients experienced MACE, and 10.4% passed away. This study employed speckle tracking echocardiography to evaluate LA and LV strain, alongside the LACI, analyzing its role in predicting MACE. CKD + DM patients showed a notable rise in LACI compared to CKD-DM patients, hinting at a link between diabetes and impaired left atrioventricular coupling in CKD. Patients with lower LACI had superior clinical outcomes during follow-up (P < 0.001). Univariate and multivariate Cox regression analyses underscored LACI as an independent predictor for heightened MACE risk in CKD 4-5 stage patients. This study highlights a potential association between diabetes and impaired left atrioventricular coupling function in CKD 4-5 stage patients, with LACI independently linked to an increased risk of MACE.

CMR-based cardiac phenotyping in different forms of heart failure

Heart failure (HF) is a heterogenous disease requiring precise diagnostics and knowledge of pathophysiological processes. Since structural and functional imaging data are scarce we hypothesized that cardiac magnetic resonance (CMR)-based analyses would provide accurate characterization and mechanistic insights into different HF groups comprising preserved (HFpEF), mid-range (HFmrEF) and reduced ejection fraction (HFrEF). 22 HFpEF, 17 HFmrEF and 15 HFrEF patients as well as 19 healthy volunteers were included. CMR image assessment contained left atrial (LA) and left ventricular (LV) volumetric evaluation as well as left atrioventricular coupling index (LACI). Furthermore, CMR feature-tracking included LV and LA strain in terms of reservoir (Es), conduit (Ee) and active boosterpump (Ea) function. CMR-based tissue characterization comprised T1 mapping as well as late-gadolinium enhancement (LGE) analyses. HFpEF patients showed predominant atrial impairment (Es 20.8%vs.25.4%, p = 0.02 and Ee 8.3%vs.13.5%, p = 0.001) and increased LACI compared to healthy controls (14.5%vs.23.3%, p = 0.004). Patients with HFmrEF showed LV enlargement but mostly preserved LA function with a compensatory increase in LA boosterpump (LA Ea: 15.0%, p = 0.049). In HFrEF LA and LV functional impairment was documented (Es: 14.2%, Ee: 5.4% p < 0.001 respectively; Ea: 8.8%, p = 0.02). This was paralleled by non-invasively assessed progressive fibrosis (T1 mapping and LGE; HFrEF > HFmrEF > HFpEF). CMR-imaging reveals insights into HF phenotypes with mainly atrial affection in HFpEF, ventricular affection with atrial compensation in HFmrEF and global impairment in HFrEF paralleled by progressive LV fibrosis. These data suggest a necessity for a personalized HF management based on imaging findings for future optimized patient management.

Effect of age and gender on ventricular-arterial coupling estimated using a non-invasive technique

BACKGROUND

Left ventricular-arterial coupling is assessed as the ratio of left ventricular end-systolic elastance (Ees) to arterial elastance (Ea). Previous studies have introduced non-invasive estimations of Ees/Ea. It requires only four variables, namely pre-ejection period, ejection time, end-systolic pressure and diastolic pressure. The aims of the present study were to clarify the reference values of Ees/Ea estimated using the noninvasive technique, and to investigate the effects of age and gender on Ees/Ea in healthy subjects.

METHODS

This retrospective study utilized data from healthy, 30-79-year-old subjects. We recorded electrocardiogram, phonocardiogram, and brachial arterial pulse waves simultaneously using the vascular screening system, and used the observed variables to calculate Ees/Ea. We separated subjects into five groups according to their age and compared Ees/Ea among the different age groups.

RESULTS

The study included 2114 males and 2292 females. Ees/Ea ranged from 1.87 to 2.04 in males, and 1.98 to 2.32 in females. We observed no age-related differences in Ees/Ea in males (p = 0.10), and significant differences in females (p < 0.001). Ees/Ea in males was not different compared to those in females in 60-69-year-old group (p = 0.92). Whereas Ees/Ea was higher in females compared to those in males in the other age groups. The differences between medians of Ees/Ea in males and those in females were 0.45 (p < 0.001), 0.24 (p < 0.001), 0.13 (p = 0.01), and 0.13 (p = 0.03) in 30-39, 40-49, 50-59, and 70-79-year-old age groups, respectively.

CONCLUSIONS

We clarified the reference values of Ees/Ea in healthy subjects. The effect of age on Ees/Ea is different in males and females, although Ees/Ea is maintained within a relatively narrow range in all subjects.

Imaging Early Life Cardiovascular Phenotype

The growing epidemics of obesity, hypertension, and diabetes, in addition to worsening environmental factors such as air pollution, water scarcity, and climate change, have fueled the continuously increasing prevalence of cardiovascular diseases (CVDs). This has caused a markedly increasing burden of CVDs that includes mortality and morbidity worldwide. Identification of subclinical CVD before overt symptoms can lead to earlier deployment of preventative pharmacological and nonpharmacologic strategies. In this regard, noninvasive imaging techniques play a significant role in identifying early CVD phenotypes. An armamentarium of imaging techniques including vascular ultrasound, echocardiography, magnetic resonance imaging, computed tomography, noninvasive computed tomography angiography, positron emission tomography, and nuclear imaging, with intrinsic strengths and limitations can be utilized to delineate incipient CVD for both clinical and research purposes. In this article, we review the various imaging modalities used for the evaluation, characterization, and quantification of early subclinical cardiovascular diseases.

Cardiovascular magnetic resonance-derived left atrioventricular coupling index and major adverse cardiac events in patients following acute myocardial infarction

BACKGROUND

Recently, a novel left atrioventricular coupling index (LACI) has been introduced providing prognostic value to predict cardiovascular events beyond common risk factors in patients without cardiovascular disease. Since data on cardiovascular magnetic resonance (CMR)-derived LACI in patients following acute myocardial infarction (AMI) are scarce, we aimed to assess the diagnostic and prognostic implications of LACI in a large AMI patient cohort.

METHODS

In total, 1046 patients following AMI were included. After primary percutaneous coronary intervention CMR imaging and subsequent functional analyses were performed. LACI was defined by the ratio of the left atrial end-diastolic volume divided by the left ventricular (LV) end-diastolic volume. Major adverse cardiac events (MACE) including death, reinfarction or heart failure within 12 months after the index event were defined as primary clinical endpoint.

RESULTS

LACI was significantly higher in patients with MACE compared to those without MACE (p < 0.001). Youden Index identified an optimal LACI cut-off at 34.7% to classify patients at high-risk (p < 0.001 on log-rank testing). Greater LACI was associated with MACE on univariate regression modeling (HR 8.1, 95% CI 3.4-14.9, p < 0.001) and after adjusting for baseline confounders and LV ejection fraction (LVEF) on multivariate regression analyses (HR 3.1 95% CI 1.0-9, p = 0.049). Furthermore, LACI assessment enabled further risk stratification in high-risk patients with impaired LV systolic function (LVEF ≤ 35%; p < 0.001 on log-rank testing).

CONCLUSION

Atrial-ventricular interaction using CMR-derived LACI is a superior measure of outcome beyond LVEF especially in high-risk patients following AMI. Trial registration ClinicalTrials.gov, NCT00712101 and NCT01612312.