Surgical mitral plasticity for chronic ischemic mitral regurgitation

Abstract

Background and Aim of the Study The outcome of mitral valve (MV) repair for chronic ischemic mitral regurgitation (IMR) is suboptimal, due to the high recurrence rate of moderate or severe mitral regurgitation (MR) during follow‐up. The MV adapts to new MR increasing its area to cover the enlarged annular area (mitral plasticity). As this process is often incomplete, we aimed to evaluate if augmenting the anterior leaflet (AL) and cutting the second‐order chords (CC) together with restrictive mitral annuloplasty, a strategy we call “surgical mitral plasticity,” could improve the midterm results of MV repair for IMR. Materials and Methods From November 2017 to October 2019, 22 patients with chronic IMR underwent surgical mitral plasticity. Mean age was 73 ± 7 years and six were female. Mean ejection fraction was 32% ± 11%, IMR grade was moderate in 10 and severe in 12. Mean clinical and echocardiographic follow‐up was 12 ± 6 months. Results There was no early death, and one patient died 6 months after surgery. Ejection fraction improved from 32% ± 15% to 40% ± 6% (P = .031). IMR was absent or mild in all patients, and none showed recurrent moderate or more IMR. Tenting area decreased significantly from 2.5 ± 0.5 to 0.5 ± 0.3 cm² and coaptation length increased from 1.9 ± 0.7 to 7.8 ± 1.6 mm. All patients were in New York Heart Association class I or II. Conclusions Mitral plasticity, if uncomplete, is ineffective in preventing IMR to become significant. Surgical mitral plasticity, by completing incomplete process of MV adaptation, has a strong rationale, which however needs to be validated with longer follow‐up.

The secret life of the mitral valve

“…The role of reparative surgery should be to “take up where the nature left” and complete the process of adaption by intervening at different levels on the MV and mimicking the natural adaptive mechanism. We have termed this surgical approach “surgical mitral plasticity.” 48 To complete what nature could not, the AL has to be augmented and lengthened (by an autologous glutaraldehyde‐treated or heterologous pericardial patch or any biological patch) and the second‐order chords have to be cut to increase the effective AL length and area (Figure 11). It is worth emphasizing the necessity of second‐order chords transection, as the fibrotic process, once started, can be progressive 49 .…”

“…(B) Postoperatively the tenting volume is minimal and the AL reaches easily the PL because of the increased length and the lack of tethering. The PL is positioned vertically (from Calafiore et al, 48 with permission). AL, anterior leaflet; IMR, ischemic mitral regurgitation; PL, posterior leaflet…”

“…(B) Postoperatively the tenting volume is minimal and the AL reaches easily the PL because of the increased length and the lack of tethering. The PL is positioned vertically (from Calafiore et al, 48 The anterior leaflet is short (21 mm) and tethered (red arrow) and is not able to coapt with the posterior leaflet. There is moderate mitral regurgitation.…”

Mitral valve—Innocent bystander or master of its own destiny?

“…The thickened retracted chords can be seen as a mal-adaptation response and cutting the second-order chords have been used to treat the process of mal-adaptation with satisfactory outcome. 16 While the concept brought in by the authors is novel, even revolutionary, realistically speaking we are still in the nascent stage of this concept of "Mitral Plasticity" both from clinical as well as cellular perspectives. In the current phase effort must be directed toward better understanding of the process of EndMT and the interplay between EndMT and VICs.…”

“…The principle of leaflet augmentation in MV repair is nothing but completing the process of incomplete adaptation. The thickened retracted chords can be seen as a mal‐adaptation response and cutting the second‐order chords have been used to treat the process of mal‐adaptation with satisfactory outcome 16 …”