Conclusions
Aortic root dilatation, with or without resultant aortic insufficiency, is commonly encountered in congenital heart surgery. The optimal management of these young patients is challenging for clinicians due to their heterogeneity and often complex surgical histories. The development of standardized guidelines for surgical interventions for these patients is also challenging due to their relative heterogeneity and infrequency in comparison to adult aneurysmal disease and connective tissue aneurysmal disease. Current evidence also suggests that the complications of dissection and rupture are less common than in adults with de novo aortic root dilatation.9 Many clinicians with experience treating these patients, including the authors of this report, advocate for the consideration of surgical intervention when aneurysms reach 5-5.5 centimeters or when there are concomitant surgical lesions that require interventions, such as aortic insufficiency causing significant heart dysfunction or concomitant right sided heart disease.10, 11
Most patients in our center have a history of connective tissue disease, a prior Ross procedure, unrepaired congenital heart disease, or prior congenital heart surgery. The Bentall procedure with either a mechanical or bioprosthetic valve has been the historical treatment of choice for patients with aortic root dilatation with or without aortic insufficiency. The Bentall procedure offers a straight-forward surgical technique and excellent long-term results with the use of mechanical valves; however, the late complications of bleeding, valve reintervention, and thrombosis remain concerning.12The Bentall procedure with the use of bioprosthetic valved conduits offers patients the avoidance of systemic anticoagulation and reasonable long-term freedom from reintervention. A recent study by Chirichilli demonstrated a freedom from reoperation at 16 years of 74.7%. While these results are impressive and makes this an appealing choice for older patients, the likelihood of reintervention for patients with decades of life expectancy is a near certainty. For these reasons, valve-sparing root replacement is an appealing treatment strategy and may be underutilized.13-15
Optimal technique for valve-sparing root replacement is another area of debate. Extensive literature has been published on the indications and efficacy of valve-sparing aortic root replacements in adult patients with aortic root dilatation; however, less literature is available guiding clinicians on the optimal indications for intervention in patients with a history of prior congenital heart surgery with only small case series published with mixed results.7, 16-19 Although other less common surgical techniques have been described, valve-sparing root replacement techniques can be grouped as either aortic root type reimplantation or aortic root type remodeling. The aortic root replacement technique is generally believed to be superior to the aortic root remodeling technique as it provides circumferential support of the aortic root and basal ring. The aortic root remodeling technique replaces the aortic sinuses but does not provide support to the intercommissural triangles and basal ring. Numerous studies have shown the aortic root reimplantation technique to have lower rates of reoperation and recurrent aortic insufficiency16. Like our results with the aortic root remodeling procedure, a study by Roubertie and colleagues examining results of valve-sparing operations in 23 children with connective tissue disease found that the aortic root reimplantation technique was superior to the aortic root remodeling technique. They observed a nearly 50% reintervention rate for patients treated with the aortic root remodeling technique.16 The largest series examining the results of valve-sparing aortic root replacement in children was published by Fraser et al in 2018 and examines the results of 100 consecutive pediatric patients.20 Most patients in this series had a history of connective tissue disease (90%) with the remaining patients having a history of congenital heart surgery. Like our results comparing the reimplantation and remodeling techniques, they observed superior freedom from reintervention with the aortic root reimplantation technique compared to the aortic root remodeling technique. Late complications of aortic insufficiency and aneurysm formation remained a concern.20
Despite the seemingly clear advantage of the aortic root reimplantation technique, it is technically more challenging to perform an adequate external aortic root dissection, especially in patients who have undergone prior arterial switch operations or the Ross procedure. The aortic root remodeling technique obviates the need for extensive external root dissection, but durability is concerning. The use of a rigid geometric subannular annuloplasty ring can standardize aortic valve repair and aortic root replacement techniques, and its utilization during the aortic root remodeling technique provides annular and intercommissural triangle stabilization while avoiding the extensive external aortic root dissection necessary for the reimplantation technique.
This study examined the outcomes of valve-sparing aortic root replacement in a congenital heart center. Over our study period we utilized three different valve-sparing techniques, (1) the traditional aortic root remodeling technique, (2) the aortic root reimplantation technique, and (3) a modified aortic root remodeling technique with the use of a rigid annuloplasty ring. The traditional aortic root remodeling technique (Group 1) was only utilized in patients with aortic root dilatation after the Ross procedure and was associated with a 100% reintervention rate over our study period, whereas the aortic root reimplantation group (Group 2) and the remodeling group with annuloplasty ring (Group 3) had 19% and 0% respectively. These results should be interpreted with caution as the average follow-up was significantly longer in Group 1 (17 years) compared to Group 1 (8 years) or Group 3 (0.7 years). Nevertheless, the average length of time to aortic valve reintervention in Group 1 and Group 2 was 5 and 3 years respectively. The largest risk for aortic valve replacement after valve-sparing root surgery in our study, as well as other studies, was higher degrees of postoperative aortic insufficiency. The immediate postoperative degree of aortic insufficiency was less in Group 3 (p = 0.03) which suggests that this technique will have acceptable durability. Similar to other studies, our findings suggest that the traditional aortic root remodeling procedure should be avoided due to poor durability.
This study does have significant limitations. First, the technique utilized over the study period was subject to surgeon preference which could impact the overall results. Secondly, there are significant differences in the follow-up duration between the three groups and only short-term follow-up is available for Group 3 patients.
In summary, valve-sparing aortic root replacement can be safely performed for a variety of indications by congenital heart surgeons. However, there is continued risk for valve failure over time. The traditional aortic root remodeling technique, when applied to patients with dilatation following the Ross procedure, should be avoided as this cohort of patients had a 100% failure rate over our study period. The aortic root reimplantation technique has acceptable results; however, there was a 20% rate of valve failure over our study period. The aortic root remodeling technique combined with the use of geometric ring annuloplasty has good short-term results; however, longer follow-up is needed to fully delineate its durability and effectiveness in comparison to the aortic root reimplantation technique.
Table 1. Stats by procedure. Group 1 = Aortic Root Remodeling 2 = Aortic Root Reimplantation. Group 3 = Aortic Root Reimplantation with rigid annuloplasty ring.