Discussion
Our results support that AVSRR for BAV is a safe option, with low mortality and low morbidity, good valve stability, and good quality of life many years after surgery.
The characteristics of our patient population were similar to those reported in other studies.(8, 11, 15) Patients were in a good state of health, which can be explained by the relatively young age of 47.4±12.5 years and the preserved left ventricular ejection fraction. Most of our patients had mild symptoms, with 3.9% having NYHA functional class III or IV, and 96.1% with Canadian Cardiovascular Society class I.
BAV is the most common congenital cardiac malformation (1–3), which can represent a health burden because some patients develop valvular and/or aortic complications. Severe aortic stenosis is typically managed with valve replacement, whereas patients with aortic regurgitation are candidates for valve repair. The reference treatment involves a composite replacement of the valve and aorta, i.e., the procedure of Bentall.(4) Generally, the population with BAV associated with aortic or valvular disease is young (3, 16), and with valve replacement, the use of a mechanical prosthesis with anticoagulation medication requires an altered lifestyle in some cases.(5, 17) Moreover, mechanical prosthesis may predispose patients to higher rates of thromboembolic events.(3) For these reasons, AVSRR techniques have been developed.
“Valve-sparing root replacement” is a collective name for multiple kinds of procedures, (7) but in general, two principal techniques are used: remodeling or reimplantation. For three decades, both approaches have yielded good results, including good long-term outcomes in the case of tricuspid aortic valves. (8,11,15) However, our center has preferred the Tirone procedure because it provides a complete stabilization of the root, including the annulus. After Modine et al. described a modified technique using a single inflow suture line, we adopted that, as well. (18) In cases of regurgitant BAV associated with aortic dilation, preservation or repair seems to be an attractive alternative to replacement. If a patient does not want a mechanical prosthesis, a bioprosthesis also is an option, but the limited durability does not make it ideal for younger individuals, and bioprostheses may increase risk of endocarditis and reintervention. (5,19,20)
Most of our cases were Sievers type I (60.8%), which reflects the natural distribution of BAV type.(21) We did, however, find a relatively frequent occurrence of type 0 (29.4%) compared to rates that Sievers et al. reported (7%). (21) Regarding intra- and post-operative outcomes, our data are in line with reports from other groups and confirm that AVSRR, such as the Tirone procedure, can be performed in patients with BAV with very low perioperative risks for morbidity and mortality (0%–2.5%) (8,11–13,16). Most of our patients had elective surgery for the Tirone procedure without other associated surgery to exclude confounding from other procedures. Holmgren and colleagues, however, still reported that even combined surgery was not associated with higher observed or relative mortality.(9)
We needed to use a graft size ≤26 mm for three women with lower heights (146, 155 and 157 cm, respectively), in whose cases the rings were measured as <20 mm at the TEE, <26 mm on computed tomography, and ≤24 mm with the Hegar sizer. This choice has not constituted a problem for the post-operative evolution, and during a follow-up of more than 5 years, we have noted no aortic regurgitation, their mean gradients were respectively 3, 9 and 11 mmHg, and their left ventricular ejection fraction measures were 60%, 60% and 65%. For patients who had an aortic root <45 mm, we offered the Tirone procedure because they had a severe aortic insufficiency. The aim is to stabilize the root for the lifetime.
There were no in-hospital deaths or deaths at 30 days, emphasizing that this operation can be performed extremely safely in experienced hands. There also were no perioperative strokes, and only one patient (2.0%) had acute coronary syndrome that presented as cardiogenic shock at 4 postoperative days. This case was particular because extracorporeal life support was needed for 5 days, two stents were placed in the right coronary artery, and dialysis was temporarily required. At the time of this writing, more than 4 years after the surgery, the patient was in good health, and TEE show a left ventricular ejection fraction of 65%, no remodeling of the aortic valve, and no aortic regurgitation. One patient (2.0%) needed reintervention for bleeding, indicating that in an experienced center, this procedure can be performed with low mortality rates.(11,16)
With our experience now extending back 15 years, we have seen stable aortic valve function in most cases. Here, we have presented outcomes at 5 years and 10 years. Although we have complete follow-up for the first case 15 years ago, a patient who is alive and doing quite well with no complications, we had only 17 patients with 10–15 years of follow-up. This early paucity can be explained by the fact that this technique was progressively integrated into the surgical options on offer and was used with increasing frequency after the first 5 years following its introduction.
As observed previously, three patients needed a reintervention after some lengthy period following the first surgery, an outcome that is better than that seen with bioprostheses in this age group. (20) When reoperation is necessary, the surgery is straightforward and consists of excising the native valve and implanting a prosthesis, as we did for the patient who had mitral insufficiency associated with moderate stenosis at 4.5 years following their Tirone procedure. Theirs is the only case in which we reoperated for reasons related to aortic stenosis, so in our 15 years of experience, the probability of developing relevant aortic stenosis has been very low. (5,16) As Schneider and colleagues also found, the incidence of endocarditis was low, with two patients in 15 years needing reoperation with Bentall’s mechanical procedure. (12)
We also can indirectly assess quality of life based on medication needs. During follow-up, we noted that only three patients needed anticoagulants, including the two patients reoperated with Bentall’s procedure, and that six patients are taking no medications at all. For us, this information provides another argument supporting valve-sparing procedures especially in the young population.