Spampinato Ricardo A, Marin-Cuartas Mateo, Kampen Antonia, Fahr Florian, Sieg Franz, Strotdrees Elfriede, Jahnke Cosima, Klaeske Kristin, Wiesner Karoline, Morningstar Jordan E, Nagata Yasufumi, Izquierdo-Garcia David, Dieterlen Maja-Theresa, Norris Russell A, Levine Robert A, Paetsch Ingo, Borger Michael A
University, Leipzig Heart Center.
Harvard Medical School.
Res Sq. 2023 May 17:rs.3.rs-2936590. doi: 10.21203/rs.3.rs-2936590/v1.
Mitral valve prolapse (MVP) is associated with left ventricle (LV) fibrosis, including the papillary muscles (PM), which is in turn linked to malignant arrhythmias. This study aims to evaluate comprehensive tissue characterization of the PM by cardiovascular magnetic resonance (CMR) imaging and its association with LV fibrosis observed by intraoperative biopsies.
MVP patients with indication for surgery due to severe mitral regurgitation (n=19) underwent a preoperative CMR with characterization of the PM: dark-appearance on cine, T1 mapping, conventional bright blood (BB) and dark blood (DB) late gadolinium enhancement (LGE). CMR T1 mapping was performed on 21 healthy volunteers as controls. LV inferobasal myocardial biopsies were obtained in MVP patients and compared to CMR findings.
MVP patients (54±10 years old, 14 male) had a dark-appearance of the PM with higher native T1 and extracellular volume (ECV) values compared with healthy volunteers (1096±78ms vs 994±54ms and 33.9±5.6% vs 25.9±3.1%, respectively, p<0.001). Seventeen MVP patients (89.5%) had fibrosis by biopsy. BB-LGE+ in LV and PM was identified in 5 (26.3%) patients, while DB-LGE+ was observed in LV in 9 (47.4%) and in PM in 15 (78.9%) patients. DB-LGE+ in PM was the only technique that showed no difference with detection of LV fibrosis by biopsy. Posteromedial PM was more frequently affected than the anterolateral (73.7% vs 36.8%, p=0.039) and correlated with biopsy-proven LV fibrosis (Rho 0.529, p=0.029).
CMR imaging in MVP patients referred for surgery shows a dark-appearance of the PM with higher T1 and ECV values compared with healthy volunteers. The presence of a positive DB-LGE at the posteromedial PM by CMR may serve as a better predictor of biopsy-proven LV inferobasal fibrosis than conventional CMR techniques.
二尖瓣脱垂（MVP）与左心室（LV）纤维化相关，包括乳头肌（PM），而这又与恶性心律失常有关。本研究旨在通过心血管磁共振（CMR）成像评估PM的综合组织特征及其与术中活检观察到的LV纤维化的关联。
因严重二尖瓣反流而有手术指征的MVP患者（n = 19）接受术前CMR检查，对PM进行特征分析：电影成像上呈暗信号、T1映射、传统亮血（BB）和黑血（DB）延迟钆增强（LGE）。对21名健康志愿者进行CMR T1映射作为对照。在MVP患者中获取LV下基底心肌活检样本，并与CMR结果进行比较。
MVP患者（54±10岁，14名男性）的PM呈暗信号，与健康志愿者相比，其固有T1和细胞外容积（ECV）值更高（分别为1096±78ms对994±54ms以及33.9±5.6%对25.9±3.1%，p<0.001）。17名MVP患者（89.5%）经活检显示有纤维化。5名（26.3%）患者在LV和PM中发现BB-LGE阳性，9名（47.4%）患者在LV中观察到DB-LGE阳性，15名（78.9%）患者在PM中观察到DB-LGE阳性。PM中的DB-LGE阳性是唯一与通过活检检测LV纤维化无差异的技术。后内侧PM比前外侧更常受累（73.7%对36.8%，p = 0.039），且与活检证实的LV纤维化相关（Rho 0.529，p = 0.029）。
因手术而接受检查的MVP患者的CMR成像显示，与健康志愿者相比，PM呈暗信号，T1和ECV值更高。CMR显示后内侧PM存在阳性DB-LGE，可能比传统CMR技术更能预测活检证实的LV下基底纤维化。
