Relevant correlation of Galectin-3 with a novel morphological classification system for LAA closure – the end of echocardiographic follow up after occluder implantation?

Introduction

Echocardiographic detection of residual peri-device leakage (PDL) after percutaneous left atrial appendage closure (LAAC) remains crucial. Significance of PDL and cardiac tissue remodeling after LAAC are still poorly understood but might have diagnostic implications. This study aims to characterize and verify if a novel echocardiographic classification system to asses the success of LAAC in combination with quantifiable biomarkers of cardiovascular tissue remodeling can help in the prediction of PDL.

Methods

Patients eligible for LAAC were included. Serum levels of the cardiac remodeling marker Galectin-3 were determined before device implantation (baseline), 45 days (45d) and 6 months (6M) after LAAC using ELISAs. Transesophageal echocardiography (TEE) was carried out to assess success of the LAAC procedure. All echo images were retrospectively evaluated by two independent investigators. Based on the amount of echodensity and luceny inside the devices after LAAC, three types can be distinguished that grade the degree of closure of the LAA. Type A has complete homogenous echodensity in 0, 45, 90 and 135°, indicating completely thrombosed device. Type B shows inhomogeneous echo-lucencies (<50% of device). Type C describes a partially thrombosed device with echo-lucencies >50%. Novel classification according to Hamadanchi, Jena, Germany (Fig. 1).

Results

We included 44 patients (characteristics listed in Table 1). Complete LAAC (without any residual flow) was achieved in 64% (28 patients) after 45 days and in 80% (35 patients) after 6 months. Mean PDL diameter was 3.5±1.5mm. Type A showed the lowest rate of PDL after 45d (Type A: 22% vs. Type B: 33% vs. Type C: 88%; p=0.007) and after 6M (Type A: 12% vs. Type B: 28% vs. Type C: 100%; p=0.002). Galectin-3 levels did not show a relevant difference regarding the type of AF at baseline (paroxysmal AF: 11.7±5.4 ng/ml vs. permanent AF: 12.1±6.3 ng/ml; p=0.45). We observed a significant increase and distribution of serum levels of Galectin-3 [ng/ml] after 45 days among the three types (Baseline: 13.1±5.8; 45d: 16.3±7.2 (Type A) vs. 19.2±8.6 (Type B) vs. 25.8±9.4 (Type C); p=0.031) followed after 6 months by a drop of Galectin-3 for type A and B toward and below baseline levels (6M: 8.9±3.1 (Type A) vs. 12.4±5.5 (Type B)) whereas type C persisted in showing elevated Galectin-3 levels compared to all other types (6M: 17.5±4.5 (Type C); p<0.001), Fig. 2. Correlation analysis shows a significant negative correlation trend between Galectin-3 and mean PDL diameter (−0.51; p=0.016) after 45 days and a relevant positive correlation after 6 months (0.58; p=0.017).

Conclusion

After LAAC, Galectin-3 levels are elevated, as a marker of myocardial fibrosis in the LAA. Depending on the degree of closure of the LAA, Galectin-3 decreases to the baseline level or stays elevated in case of relevant PDL and could therefore be considered as a new biomarker for closure success.

Funding Acknowledgement

Type of funding source: None

Dynamics of Galectin-3 serum levels after percutaneous occlusion of the left atrial appendage: a new surrogate parameter for successful LAA closure?

Introduction

Left atrial cardiac tissue remodeling following left atrial appendage closure (LAAC) is a scientifically neglected phenomenon until now but might have impact on functional outcome of patients suffering from atrial fibrillation (AF). Thus, our study is focused on quantification of key biomarkers reflecting fibrosis development as a major component within cardiovascular tissue remodeling.

Methods

Patients (CHA2DS2VASC score ≥1, HASBLED score ≥3) with bleeding complications under anticoagulation therapy and therefore eligible for LAAC were included in the present study. Serum levels of biomarkers of cardiac fibrosis and remodeling (Galectin-3, ST2/IL-2, ST2/IL-1, B domain containing Tenascin-C (B+ Tn-C), C domain containing Tenascin- C (C+ Tn-C)) were determined before device implantation (baseline), 45 days (45d) and 6 months (6M) after LAAC using commercially available ELISAs. To quantify functional outcome, all patients performed a 6-minutes walk test (6- MWT). Transesophageal echocardiography (TEE) was carried out to assess success of the LAAC procedure regarding peri-device leakage (PDL).

Results

We included 33 patients (age: 73.5±6.7 years; 21 men (64%) and 12 women (36%); BMI: 29.1±5.1 kg/m2; CHA2DS2VASC score: 4.2±1.2; left ventricular ejection fraction: 61.1±9.3%; mean occluder size: 25.9±3.9 mm; type of AF: 46% paroxysmal (15 patients), 55% permanent (18 patients)). Complete LAAC (without any residual low) was achieved in 60% (19 patients) after 45 days and in 87% (29 patients) after 6 months. At baseline, Galectin-3 levels did not show a relevant difference regarding the type of AF (paroxysmal AF: 14.7±5.4 ng/ml vs. permanent AF: 13.1±6.3 ng/ml; p=0.45). We observed a significant increase of serum levels of Galectin-3 [ng/ml] after 45 days vs. baseline (baseline: 13.3±5.8 vs. 45d: 18.3±10.6; p=0.005) with a return to baseline levels after 6 months (baseline: 13.3±5.8 vs. 6M: 12.5±5.4; p=0.28). Compared to patients with successful LAAC, patients with PDL had a trend towards higher levels of Galectin-3 after 6 months (11.3±5.5 ng/ml vs. 16.1±4.1 ng/ml, p=0.09). Measurements of other fibrosis markers were statistically not significantly different. The walking distance measured by the 6-MWT increased significantly from 298.5±89.5 meters at baseline to 335.5±95.1 meters (p=0.04) after 45d and remained significantly elevated after 6M (346.7±122.7 meters; p=0.02).

Conclusion

The implantation of an LAA occluder device is accompanied by significantly increased circulating levels of the fibrosis biomarker Galectin-3 after 45 days in patients with AF. The regression in serum levels after 6 months probably reflects a successful fibrotic remodeling in the left atrial appendage over time and might be used as surrogate parameter for LAAC success. Increased and stable exercise tolerance after 45 days can be observed.

Funding Acknowledgement

Type of funding source: None