Symmetric repair of the unicuspid aortic valve

Unicuspid (and commonly unicommissural) morphology is one of the congenital variants of the aortic valve, presenting as stenosis, mixed dysfunction or pure regurgitation [1]. It is frequently mistaken for bicuspid aortic valve morphology [1]. Patients with unicuspid aortic valves require treatment at a young age [2], at times even as neonates or infants [3].

The unicuspid and unicommissural morphology is characterized by the hypoplasia of 2 commissures with variable degrees of cusp fusion [3]. There is only 1 normally developed and thus functional commissure, and there is no cusp fusion in its vicinity. The morphologic difference between bicuspid (2 functional commissures) and unicuspid have led a repair approach should including the creation of 1 additional functional commissure and adding tissue as needed [4]. Our repair technique [5] thus creates a symmetric bicuspid valve; it only requires the addition of patch material for adequate cusp size and unrestricted motion [5].

This concept has been shown to be reproducible with the limited amount of myocardial ischaemia compared to other operations [5, 6]; its haemodynamic function has been good [6]. The drawback of this concept has been the degeneration of the patch material that is necessary for the repair [5]. In fact, degeneration of autologous pericardium has been the most frequent reason for reoperation long-term [5, 7]. Synthetic material has yielded poor durability [8], and there is as yet only limited evidence that decellularized pericardium may be a better solution, at least in paediatric individuals [7]. Thus, in essence, there is no proven material available that equals the performance of native cusp tissue.

It therefore appears logical to use native cusp tissue if a sufficient amount is present, as described in the current report [9]. The creation of valve and commissural configuration is identical to the standard technique [5]; instead of discarding the right cusp tissue, it is simply detached from its aortic insertion and reattached to the aortic wall to achieve the intended configuration. A prerequisite is the sufficient size of the right cusp as judged by its geometric height [10]. We have employed such a modification infrequently, i.e. in 8 of 250 unicuspid repairs. For us, the prerequisite has been a geometric height of the rudimentary right cusp of >16–17 mm and preserved tissue quality. We have at times employed the term ‘recycling’ for such a manoeuvre with native tissue.

While this technique has not eliminated the need for reoperation, we have been positively impressed with the stability and functional integrity of the relocated cusp tissue. Further experience and follow-up will be needed to judge the long-term value of this modification.

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