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.