Cardiology Department, Hospital de Santa Cruz, Centro Hospitalar Lisboa Ocidental, Lisbon, Portugal.
Nova Medical School, Lisbon, Portugal.
Cardiovasc Ultrasound. 2023 Aug 12;21(1):14. doi: 10.1186/s12947-023-00311-x.
Increased collagen content of the myocardium modifies tissue reflectivity and integrated backscatter (IBS) indexes are suggested as markers of myocardial fibrosis (MF). We sought to assess the correlation between calibrated (c) IBS and bidimensional (2D) strain derived IBS with left ventricular (LV) MF in patients with severe aortic stenosis (AS).
We made a prospective observational cohort study including 157 patients with severe AS referred for surgical aortic valve replacement (AVR), with complete preoperative transthoracic echocardiography, cardiac magnetic resonance (CMR) and endomyocardial biopsy (EMB) obtained from the anterior basal septum at the time of surgery. Two groups of 30 patients were specifically evaluated, with and without late gadolinium enhancement (LGE) at CMR. IBS was obtained at QRS peak from both parasternal long axis (PLAX) and apical-three-chamber (AP3C) views and measured in decibels (dB). Whole-cardiac cycle IBS at basal anterior septum was obtained from 2D longitudinal strain. Correlation analysis of reflectivity indexes was performed with global and segmental (anterior basal septum) values of native T1 and extracellular volume (ECV), and EMB collagen volume fraction (CVF) (Masson´s Trichrome). IBS values were compared in both group of patients (LGE + vs. LGE -). 60 patients (74 [36-74] years, 45% male) with high gradient (mean gradient: 63 ± 20mmHg), normal flow (45 ± 10mL/m) AS and preserved left ventricular ejection fraction (60 ± 9%) were included. Basal septum cIBS was - 17.45 (-31.2-10.95) and - 9.17 ± 9.45dB from PLAX and A3C views, respectively. No significant correlations were found between IBS and both non-invasive CMR tissue characterization and CVF: median MF of 9.7(2.1-79.9)%. Acoustic indexes were not significantly different according to the presence of pre-operative LGE.
In this group of patients with classical severe AS, IBS reflectivity indexes are of no added value to discriminate the presence of MF.
心肌胶原含量的增加会改变组织的反射率，而积分反向散射（IBS）指数被认为是心肌纤维化（MF）的标志物。我们旨在评估校准 IBS（cIBS）与二维（2D）应变衍生 IBS 与严重主动脉瓣狭窄（AS）患者左心室（LV）MF 之间的相关性。
我们进行了一项前瞻性观察队列研究，纳入了 157 名因严重 AS 而接受外科主动脉瓣置换术（AVR）的患者，所有患者均在术前完成了经胸超声心动图、心脏磁共振（CMR）和手术时从前间隔基底部获得的心肌活检（EMB）。专门评估了两组 30 名患者，一组有 CMR 延迟钆增强（LGE），另一组没有。从胸骨旁长轴（PLAX）和心尖三腔（AP3C）视图的 QRS 波峰获得 IBS，并以分贝（dB）测量。从前间隔基底获得 2D 纵向应变的全心脏周期 IBS。用整体和节段（前基底间隔）的天然 T1 和细胞外容积（ECV）以及 EMB 胶原容积分数（CVF）（Masson 染色）对反射率指数进行相关性分析。比较了两组患者的 IBS 值（LGE+ vs. LGE-）。纳入 60 名患者（74[36-74]岁，45%为男性），均为高梯度（平均梯度：63±20mmHg）、正常流量（45±10mL/m）AS 和保留的左心室射血分数（60±9%）。基底间隔 cIBS 分别为-17.45（-31.2-10.95）和-9.17±9.45dB，来自 PLAX 和 A3C 视图。IBS 与非侵入性 CMR 组织特征和 CVF 之间无显著相关性：中位 MF 为 9.7（2.1-79.9）%。根据术前 LGE 的存在，声学指标无显著差异。
在这组患有典型严重 AS 的患者中，IBS 反射率指数对于鉴别 MF 的存在没有额外价值。
