Department of Cardiovascular Medicine, Lahey Hospital and Medical Center, Burlington, Massachusetts.
Tufts University School of Medicine, Boston, Massachusetts.
JAMA Cardiol. 2020 Apr 1;5(4):476-481. doi: 10.1001/jamacardio.2019.5980.
Two randomized clinical trials of transcatheter edge-to-edge mitral valve repair in patients with secondary mitral regurgitation (the Multicentre Randomized Study of Percutaneous Mitral Valve Repair MitraClip Device in Patients With Severe Secondary Mitral Regurgitation [MITRA-FR] and the Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients with Functional Mitral Regurgitation [COAPT]) report clinical outcome disparities that are largely unexplained. This appraisal sought to provide insight and an explanation for the differences in clinical outcomes (survival and hospitalization rates) in the 2 clinical trials. The mean echocardiogram Doppler results (and derived volume parameters) from each of the 2 clinical trials were compared and examined relative to the clinical outcomes. Special emphasis was placed on the assessment of mitral regurgitation proportionality coefficients that were determined as the ratio of effective regurgitant orifice area (EROA) to end-diastolic volume and the ratio of mitral regurgitant volume to end-diastolic volume.
In this analysis of the differences in the clinical outcomes of the MITRA-FR and COAPT clinical trials, the ratio of the EROA to the end-diastolic volume in the COAPT study was found to be twice that of the MITRA-FR study (0.002 cm-1 vs 0.001 cm-1, respectively). The finding of a larger proportional EROA in the COAPT study suggests more severe mitral regurgitation compared with the MITRA-FR study, thereby providing a potential explanation for the different outcomes in the 2 clinical trials. In contrast, the ratio of the mitral regurgitant volume to the end-diastolic volume in the COAPT study was similar to (but slightly lower than) that of the MITRA-FR study (0.15 vs 0.18, respectively), indicating that the proportional mitral regurgitant volume was comparable in the 2 clinical trials. This finding contradicts the conclusions of the EROA analysis.
The results of proportionality analyses based on EROA differ from those based on a volume analysis. This disparity casts doubt on the notion that an EROA analysis alone can explain the different results of the 2 randomized clinical trials.
两项经导管缘对缘二尖瓣修复术治疗继发性二尖瓣反流的随机临床试验（多中心随机研究经皮二尖瓣修复 MitraClip 装置治疗严重继发性二尖瓣反流患者[MITRA-FR]和心血管结局评估经皮治疗心力衰竭伴功能性二尖瓣反流患者的 MitraClip 治疗[COAPT]）报告了临床结果差异，这些差异在很大程度上无法解释。本评价旨在为这两项临床试验的临床结果（生存率和住院率）差异提供深入了解和解释。比较了这两项临床试验中每一项的平均超声心动图多普勒结果（和衍生的容量参数），并根据临床结果进行了检查。特别强调评估二尖瓣反流比例系数，该系数定义为有效反流口面积（EROA）与舒张末期容积之比和二尖瓣反流容积与舒张末期容积之比。
在对 MITRA-FR 和 COAPT 临床试验临床结果差异的分析中，发现 COAPT 研究中 EROA 与舒张末期容积的比值是 MITRA-FR 研究的两倍（分别为 0.002 cm-1 和 0.001 cm-1）。COAPT 研究中较大的比例 EROA 表明二尖瓣反流比 MITRA-FR 研究更严重，从而为这两项临床试验的不同结果提供了潜在解释。相比之下，COAPT 研究中二尖瓣反流容积与舒张末期容积的比值与 MITRA-FR 研究相似（但略低）（分别为 0.15 和 0.18），表明这两项临床试验中比例性二尖瓣反流容积相当。这一发现与 EROA 分析的结论相矛盾。
基于 EROA 的比例分析结果与基于容积分析的结果不同。这种差异使人怀疑仅基于 EROA 分析是否能解释这两项随机临床试验的不同结果。
