Background

Among current transcatheter therapies for the treatment of mitral regurgitation, the MitraClip (MC; Abbott Vascular, Abbott Park, IL) system is the most commonly used. MitraClip implantation is usually contraindicated in patients with a mitral valve area (MVA) < 4.0 cm². However, little is known about the real impact of MC implantation on MVA. Our goal was to investigate the factors influencing MVA reduction and derive the minimal MVA required to prevent the development of a clinically significant mitral stenosis (MVA < 1.5 cm²) in different clinical scenarios.

Methods

Using three-dimensional data sets, the annulus and leaflet anatomy and MVA before clip implantation (MVA_BC) were assessed. After each MC implant (NTR or XTR), the relative MVA reduction and the absolute residual MVA were measured and their predictors evaluated.

Results

The present analysis included 116 patients. An MC XTR was the first device implanted in 50% of the subjects, and 53% were treated with a single implant. The MVA reduction following one XTR was 57% ± 7% versus 52% ± 8% after one NTR (P = .001). A lower MVA reduction was observed when the MC was placed commissural/central versus paracentral (50% ± 8% vs 57% ± 7%, P < .0001). After a second device, the additional MVA reduction was higher when creating a triple-compared with a double-orifice morphology (34% ± 11% vs 25% ± 9%, P = .001). The MVA after one MC correlated with MVA_BC as well as with the clip type and position (r = 0.91, P < .0001). The MVA_BC, orifice morphology, and first device position predicted MVA after two implants (r = 0.82, P < .0001). Based on the mathematical relationship between these parameters, the minimal MVA_BC needed in eight different clinical scenarios was summarized in a decision algorithm: the values ranged from 3.5 to 4.7 cm² for one and 4.5 to 6.3 cm² for two MC strategies.

Conclusions

The minimal native MVA preventing clinically relevant MS after transcatheter edge-to-edge repair is predicted by the number and location of clip(s), orifice morphology, and device type. Based on these parameters, an algorithm has been derived to optimize patient selection and preprocedural planning.

中文翻译：

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经导管边缘到边缘修复后三维二尖瓣面积减少的解剖学和技术预测因素

背景

在目前用于治疗二尖瓣关闭不全的经导管疗法中，Mi​​traClip (MC; Abbott Vascular, Abbott Park, IL) 系统是最常用的。MitraClip 植入通常禁忌于二尖瓣面积 (MVA) < 4.0 cm ²的患者。然而，关于 MC 注入对 MVA 的真正影响知之甚少。我们的目标是调查影响 MVA 减少的因素，并得出在不同临床情况下防止发生具有临床意义的二尖瓣狭窄 (MVA < 1.5 cm ^{2 ) 所需的最小 MVA。}

方法

使用三维数据集，评估瓣环和瓣叶解剖以及夹子植入前的 MVA (MVA _{BC )。}在每次 MC 植入（NTR 或 XTR）后，测量相对 MVA 减少和绝对残余 MVA 并评估其预测因子。

结果

目前的分析包括 116 名患者。50% 的受试者是第一个植入 MC XTR 的装置，53% 的受试者接受了单一植入物的治疗。一次 XTR 后的 MVA 减少为 57% ± 7%，而一次 NTR 后为 52% ± 8% ( P  = .001)。当 MC 置于连合/中央与旁中央时，观察到较低的 MVA 减少（50% ± 8% 对 57% ± 7%，P  < .0001）。在第二个装置之后，与双孔形态相比，创建三倍体时额外的 MVA 降低更高（34% ± 11% 对 25% ± 9%，P  = .001）。一次 MC 后的 MVA 与 MVA _BC以及夹子类型和位置相关 ( r  = 0.91, P  < .0001)。MVA _BC、孔口形态和第一个装置位置预测了两次植入后的 MVA ( r  = 0.82, P  < .0001)。基于这些参数之间的数学关系，在一个决策算法中总结了八种不同临床场景所需的最小 MVA _BC：一种 MC 策略的值范围为 3.5 至 4.7 cm ² ，两种 MC 策略的值范围为 4.5 至 6.3 cm ²。

结论

经导管边缘到边缘修复后预防临床相关 MS 的最小天然 MVA 可通过夹子的数量和位置、孔口形态和设备类型来预测。基于这些参数，推导出了一种算法来优化患者选择和术前计划。