Prognostic value of left atrial volume index in patients with rheumatic mitral stenosis

Differentiation of the severity of rheumatic mitral stenosis using dimensionless index and its association with outcomes

Introduction

The severity of mitral stenosis (MS) is commonly assessed using mitral valve area (MVA) measured with transthoracic echocardiography (TTE). The dimensionless index (DI) of mitral valve (MV) was recently studied in degenerative MS. We evaluated DI MV in rheumatic MS and studied its relationship with clinical outcomes.

Methods

We studied 406 cases of rheumatic MS in a retrospective single centre cohort study, with 174 in a derivation cohort, 121 in a TTE validation cohort, and 111 in a transoesophageal echocardiography (TEE) validation cohort. DI MV was calculated by dividing the left ventricular outflow tract pulsed-wave Doppler time-velocity integral (TVI) by the MV continuous-wave Doppler TVI. DI MV was compared against MV area using the two-dimensional planimetry, pressure half-time and continuity equation methods, or, in the TEE validation cohort, TEE-derived three-dimensional planimetry. Severe MS was defined as an MV area ≤1.5 cm2. Outcomes pertaining to all-cause death and mitral valve intervention were studied in the former two cohorts.

Results

All-in-all, 231 patients (56.9 %) across the three cohorts had severe MS. In the derivation cohort, ROC analysis showed that DI MV could accurately classify MS severity (AUC = 0.838, 95 % CI, 0.780-0.897, p < 0.001). DI MV ≤ 0.25 and DI MV ≥ 0.40 had high specificity for identifying severe (93.7 %) and non-severe MS (93.7 %) respectively. In the validation cohorts, these respectively showed similar specificity for identifying severe (93.8 %) and non-severe MS (91.4 %). In the derivation and TTE validation cohorts, the median follow up duration was 6.32 years (interquartile range, 4.22-10.3 years) with 90 deaths (30.5 %) and 50 patients (17.0 %) undergoing MV intervention. DI MV was univariately significant (HR = 0.075, 95 % CI 0.0215-0.378, p = 0.002) in Cox regression for a composite outcome of death and MV intervention. DI MV remained independently associated with the composite outcome in multivariate analysis.

Conclusion

DI MV can help rule-in or rule-out severe MS with high specificity, and is independently associated with composite outcomes of death and MV intervention.

Association of Yeo's index with clinical outcomes in rheumatic mitral stenosis

Yeo's index, the product of the mitral leaflet separation index and dimensionless index of mitral valve (MV), was recently described to accurately identify severe rheumatic mitral stenosis (MS). We assess the association between Yeo's index and clinical outcomes in patients with rheumatic MS. We studied 297 patients with rheumatic MS. Clinical and echocardiographic data were obtained from the electronic medical record and Yeo's index was measured in all cases. The outcome studied was a composite of all cause death, heart failure (HF) hospitalisation, MV intervention and stroke or transient ischaemic attack. We also performed subgroup analysis of patients without pre-existing atrial fibrillation (AF) to assess for association with new onset AF. The median follow up was 6.3 years; 145 patients (48.8%) developed the composite outcome. Yeo's index (p < 0.001), mitral valve area (MVA) by pressure half-time (PHT) (p = 0.028) and planimetry (p < 0.001), age (p = 0.016), history of diabetes mellitus (p = 0.029), previous HF (p = 0.021), left ventricular ejection fraction (p = 0.022), and pulmonary artery systolic pressure (p = 0.007) were univariately associated with the composite outcome. Yeo's index remained independently associated with the composite outcome in multivariate analysis (p < 0.001, HR 0.094, 95% CI 0.260-0.340). This was primarily driven by MV intervention. In a subgroup analysis of patients without pre-existing AF, Yeo's index was independently associated with new onset AF (p = 0.024, HR 0.354, 95% CI 0.143-0.874). This demonstrated that Yeo's index was independently associated with clinical outcomes in patients with rheumatic MS which was mainly driven by MV intervention.

Correlation between circulating fibrosis biomarkers with left atrial function and left atrial volume index in rheumatic mitral stenosis

Mitral stenosis is the most common rheumatic heart disease (RHD) disorder worldwide, including in Indonesia. This pathological condition causes left atrial pressure, leading to left atrial fibrosis that affects the structure and function of the left atrial as well as the clinical condition. The aim of this study was to assess the correlation between circulating fibrosis biomarkers with net atrioventricular compliance (Cn) as a parameter of left atrial function, and left atrial volume index (LAVI) as a parameter left atrium structure of changes. A cross-sectional study was conducted at Panti Rahayu Hospital and Permata Bunda Hospital, Purwodadi, Central Java, with a total of 40 RHD patients with severe mitral stenosis. The ELISA was used to measure the levels of carboxy-terminal propeptide of type I procollagen (PICP), matrix metalloproteinase I (MMP-1), tissue inhibitor matrix metalloproteinase 1 (TIMP-1), and transforming growth factor-β1 (TGF-β1). The left atrial function was assessed by measuring Cn, and the LAVI parameters were measured to assess left atrium structure/size. The mean levels of circulating fibrosis biomarkers were as follows: PICP 153.96±89.12 ng/mL; MMP-1 1.44±2.12 ng/mL; MMP-1/TIMP-1 ratio 0.38±0.54 and TGF-β1 2.66±1.96 pg/mL. From the echocardiographic evaluation, the mean Cn was 5.24±1.93 mL/mmHg and the mean LAVI was 152.55±79.36 mL/m2. There were significant correlation between MMP-1 and MMP-1/TIMP-1 ratio with Cn (r=0.345 and r=0.333, respectively; both had p<0.05). PICP and TGF-β1 biomarkers did not significantly correlate with Cn (p>0.05). Meanwhile, none of the biomarkers had a significant correlation with LAVI (p>0.05). This study highlights that MMP-1 and MMP-1/TIMP-1 ratio are potentially to be used as markers to determine the Cn in RHD patients with severe mitral stenosis. However, further studies with a higher sample size are needed to confirm this finding.

Chronic mild to moderate mitral regurgitation will not have an impact on left atrial strain parameters in the pediatric population

BACKGROUND

Left atrial strain (LAS) analysis represents a newer non-invasive, sensitive and specific technique for assessing left atrial (LA) function and early detection of its deformation and dysfunction. However, its applicability in mitral regurgitation (MR) in pediatric population remains unexplored, raising pertinent questions regarding its potential role in evaluating the severity and progression of the disease.

OBJECTIVE

To investigate the impact of chronic MR in children and adolescents on LA remodeling and function.

METHODS

The study included 100 participants. Patients with primary and secondary chronic MR lasting at least 5 years fit our inclusion criteria. The exclusion criteria from the study were: patients with functional mitral regurgitation due to primary cardiomyopathies, patients with artificial mitral valve, patients with MR who had previously undergone surgery due to obstructive lesions of the left heart (aortic stenosis, coarctation of the aorta), patients with significant atrial rhythm disorders (atrial fibrillation, atrial flutter). The echocardiographic recordings were conducted by two different cardiologists. Outcome data was reported as mean and standard deviation (SD) or median and interquartile range (Q1-Q3).

RESULTS

The study included 100 participants, of whom 50 had MR and the remaining 50 were without MR. The average age of all participants was 15.8 ± 1.2 years, with a gender distribution of 37 males and 63 females. There was a significant difference in the values of LA volume index (LAVI), which were higher in patients with MR (p= 0.0001), S/D ratio (and parameters S and D; p= 0.001, p= 0.0001, p= 0.013), mitral annulus radius (p= 0.0001), E/A ratio (p= 0.0001), as well as septal e' (m/s), lateral e' (m/s), and average E/e' ratio, along with the values of TV peak gradient and LV global longitudinal strain (%). There was no significant difference in LA strain parameters, nor in LA stiffness index (LASI).

CONCLUSION

Our findings revealed significant differences in several echocardiographic parameters in pediatric patients with MR relative to those without MR, providing insight into the multifaceted cardiac structural and functional effects of MR in this vulnerable population.

Prognostic value of left atrial volume index in degenerative mitral stenosis

Purpose

Degenerative mitral stenosis (DMS) is associated with a poor prognosis. Although mean transmitral gradient (TMG) has shown a good correlation with outcome, little is known about the association between other echocardiographic parameters and prognosis in patients with DMS. The current study aimed to evaluate the prognostic value of left atrial volume index (LAVI) in patients with DMS.

Methods

A total of 155 patients with DMS (72[63–80] years, 67% female) were included. The population was divided according to LAVI: normal-sized LAVI (LAVI ≤ 34 ml/m2); and enlarged LAVI (> 34 ml/m2).

Results

Patients with enlarged LAVI had a higher left ventricular mass index (120[96–146] vs. 91[70–112] g/m2 p < 0.001), as well as a higher prevalence of significant mitral regurgitation and severe aortic stenosis (23% vs. 10% p = 0.046 and 38% vs. 15% p=0.001, respectively) compared to patients with normal-sized LAVI. During a median follow-up of 25 months, 56 (36%) patients died. Patients with enlarged LAVI had worse prognosis compared to patients with normal-sized LAVI (p = 0.026). In multivariable Cox regression model, an enlarged LAVI was independently associated with all-cause mortality (HR 2.009, 95% CI 1.040 to 3.880, P = 0.038).

Conclusion

An enlarged LAVI (> 34 ml/m2) is significantly associated with excess mortality in patients with DMS. After adjusting for potential confounders, an enlarged LAVI was the only parameter that remained independently associated with prognosis.