The aortic valve reimplantation technique is a technically challenging procedure, and mostly performed for young and otherwise healthy patients with intact tricuspid AV and minimal AR to preserve the native AV and avoid valve replacement therapy [12]. Currently, the indications for AVS have been extended in high-risk patients with complex AR, particularly for individuals with congenitally determined AV morphology and aortopathy (connective tissue disorders) [13]. A thorough perception of the aortic root three-dimensional anatomy and functional interaction with AV cusps as an entire unit led to refinements and standardisation of AV repair sparing techniques [10]. Despite growing interest, primary ACR techniques are still debatable as fewer studies addressing this subject as more complex and less reproducible, especially in patients with severe preoperative AR, various phenotypes of the BAV, and reoperations [14]. Herein, we analysed our single institutional experience with AVS and associated ACR focusing on long-term outcomes and predictors of recurrent AR. David et al. [3] reported the longest available outcomes in a series of 333 patients (ACR in 64.4%). The mean age of the patiens and their clinical follow-up was 46 ± 15 years and 10.3 ± 6.8 years, respectively. In this cohort, the early mortality was 1.2% and the overall survival at 10 and 15 years was 89.5 ± 2.0% and 77.9 ± 3.9%, respectively. In a recent study, Mastrobuoni et al. [5] reported the long-term experience in 440 consecutive patients (mean age, 49 years; mean follow-up of five years; completeness of follow-up was 78%.) with aortic root aneurysm undergoing the reimplantation technique and a high number of associated ACR procedures (72.7%). The in-hospital mortality was 0.7% and the survival was 79.7% ± 3.8% at 10 years. In this study, we were able to maintain low mortality and morbidity in elective surgery for this young patients cohort with a normal comparable life expectancy; thereafter, in accordance with to most recently published reports [3,4,5,6]. Furthermore, De Kerchove et al. [2] reported that neither severe preoperative AR nor associated ACR had an impact on the durability of the AV repair and did not increase the risk of recurrent AR, in contrast to the findings in the meta-analysis conducted by Arabkhani et al. [15]. From the beginning of the AV repair sparing program, we performed more aggressive approaches combining AV reimplantation with ACR for bicuspid and tricuspid leaking AVs, who presented with significant preoperative AR (86.4%).
Moreover, a high percentage of the patients (83.9%) for type II AR dysfuntion underwent free-margin central plication as the most simple, reproducible, and efficient technique in case of cusp prolapse repair [3, 5].
Patients with chronic severe AR and dilated root might have frequently overstretched, thin, and prolapsing AV cusp tissue (type II AR dysfuntion) due to constant haemodynamic stress, thereby mandating extensive AV repair with different ACR techniques to reestablish competency of the aortic valve [1]. Other large AV sparing repair series (including the remodeling technique with external annuloplasty) demonstrated an increasing number of patients who required additional cusp repair due to unrecognised cusp disease or technically induced prolapse after reconstruction of the aortic root [5, 16].
Intraoperative TEE is an important tool in selecting patients for AV repair sparing surgery with guided specific reconstructive strategies and immediate evaluation of proper aortic valve performance after repair [17]. In 2009, several intraoperative predictors of recurrent AR after AV repair sparing surgery have been identified by le Polain de Waroux et al. [18] in retrospective study of 186 consecutive patients based on intraoperative TEE imaging. The main predictors have been described as follows: the presence of more than mild AR postoperatively, eccentric jet, coaptation below the annular plane, a coaptation length < 4 mm, and an enlarged aortic annulus. In our study, the multivariate analysis confirmed the tendency towards recurrent AR (> 2+) in patients with mild residual AR after surgery. However, this finding still has limited power to draw conclusions due to the relatively small number of events and needs other additional criteria for further evaluation. In recent years, Bierbach and Schäfers et al. [19] introduced the effective height concept into clinical practice as a prognostic predictor with the quantitative value to reestablish perfect valve configuration and long-term valve function. The effective height is measured and compared at equal distances beetwen cusps (from the middle of the free margin to the plane passing through the cusp insertion plane) intraoperatively by special calipers or with TEE evaluation [20]. Our study correlates well with findings from the Schäfers group in terms of low effective height value (< 9 mm), by multivariate analysis it was another independent predictor to induce recurrent AR > 2+ (p= 0.02). Therefore, a low effective height value after root reconstruction indicates residual cusp prolapse and mandates additional free-margin central plication in order to increase the coaptation height, as has been indicated in the literature [16]. We have applied free-margin central plication as our first choice; however, very aggressive prolapse correction in several instances was associated with recurrent AR due to restriction. At the beginning of our study, we tried triangular raphe resection (BAV type 1) with a direct suture; however, within the first years after initial surgery, AV failure presented and reoperations were necessary. Two patients experienced dehiscence of the direct suture line likely due to an inadequate quantitity of AV cusp tissue. In the literature, the lack of cusp tissue in BAV morphology is defined when the geometric height of the non-fused aortic cusp is 19 mm or less [21]. We stopped to employ this technique and changed our operative strategy to more consistent techniques (e.g., free margin central plication) to preserve tension-free repair and AV cusp mobility. All the components of the aortic root complex along with AV cusps have to be addressed and repaired with meticulous surgical techniques and comprehensive TEE evaluation to achieve excellent repair and long-term outcomes [22]. On the other hand, AV replacement with AV and composite root substitutes could be performed safely with less technical dificulty in patients with questionable AV quality and less than perfect AV reconstruction. In a recent study, Ouzounian et al. [23] reported comparative long-term outcomes and trends between patients undergoing AVS and AV root replacement surgery with composite valve grafts (mechanical and tissue) in patients with AR and aortic root pathology. The results of this analysis revealed that the rate of cumulative risk of valve-related complications increases after mechanical AV root replacement with time due to lifelong anticoagulation therapy (HR 5.6; p= 0.008), whereas tissue substitutes pose potential reoperation risk due to structural degeneration (HR 6.9; p= 0.003) compared with AVS surgery [23]. In contrast, the AV sparing repair surgery may be a considerable alternative to avoid prosthetic valve-related complications and lifelong anticoagulation therapy for active patients seeking normal life expectancy. Our analysis confirmed the low rates of valve-related complications (reoperation, thromboembolism, bleeding, infective endocarditis) without the need of lifelong anticoagulation therapy as reported by Saczkowski et al. [24] in a systematic review of AV preservation and repair. We believe that our data supplement existing outcomes and support the current trend towards extention of the indications for the AV sparing repair surgery for higher-risk patients rather than conventional replacement therapy; however, there is a lack of data directly comparing the AV sparing repair surgery to replacement.
Limitations
This single-centre study is limited by its retrospective design. Certainly, heterogeneity of the patients, different ACR techniques, as well as the accumulation of surgical experience with the inevitable phase of the learning curve had major implications for reproducibility and clinically relevant outcomes. Continued follow-up and further standardised reporting are necessary to draw definitive conclusions for this challenging patient population.