Material and Methods
For this retrospective analysis, we included data for all patients with BAV who underwent aortic root replacement using Tirone’s procedure from December 2007 through January 2022. Patients with acute aortic dissection or age <18 years were excluded. The study was approved by local Ethics Committee (IRB00013412, “CHU de Clermont Ferrand IRB #1”, IRB number 2022-CF015) with compliance to the French policy of individual data protection.
In brief, after the chest was opened with a median sternotomy, and application of systemic heparinization, the patient was started on extracorporeal circulation with direct cannulation of the arch or ascending aorta and right atrial cannulation. Cardiac arrest was achieved by means of infusion of cold blood cardioplegia, first anterograde into the coronary ostia and then retrograde in the majority of cases. Transsection to open the ascending aorta was done above the commissures plane. The aortic root and the valve were carefully inspected by the operating surgeon. The BAV was classified according to Sievers, followed by cutting of the coronary ostia, dissection from the aortic root to the aortic annulus plane, and resection of the sinuses.
After suspension of the commissures, we used a Hegar dilator to measure the aortic annulus. The aortic valve was carefully assessed for configuration and coaptation. When cups presented calcification, decalcification was performed first. In all instances, a Dacron graft was used, initially with a graft 4 mm larger than the measured diameter of the aortic annulus. Then after a few years, a Dacron graft 2 mm larger was usually chosen, although sometimes a graft was used that was the same diameter of the aortic annulus. We routinely use Vascutek Gelweave® (Vascutek Terumo, Glasgow, Scotland). Initially, we performed a proximal subannular fixation of the vascular prosthesis by U-shaped stitches associated with a running suture, but we changed to a technique using a single inflow suture line.
After aortic valve reimplantation and co-aptation assessment, we used a Schäfers caliper to measure the plicature started by the unfused leaflet at 10/12 mm. Measurement of the other leaflet was impossible because of the symphysis and hypoplastic commissure. We then operated on the second leaflet (symphysis leaflet) to obtain an equal length of the free edges. Additional repair was performed as needed, consisting of fenestration and/or patch repair. According to the operating surgeon’s preference, the central plication sutures were performed with 6-0 polypropylene stitches. Reimplantation of the coronary ostia was performed using the button technique.
For follow-up, all patients underwent preoperative transthoracic echocardiography (TTE), intraoperative transesophageal echocardiography, and postoperative TTE before hospital discharge, yearly thereafter for 5 years, and then less frequently. Points of interest included the diameter of the aortic annulus, the mode of aortic valve insufficiency and potential prolapse and sclerosis, the mean systolic gradients, and the left ventricular ejection fraction. Events were defined as such by timing of their initial diagnosis.
Statistical analysis was performed using Stata software (version 15; StataCorp, College Station, Texas, USA). All tests were two-sided, with a Type I error set at 0.05. Categorical variables are expressed as number of patients and associated percentages, and continuous variables as mean±standard deviation or median [25th; 75th percentiles], according to statistical distribution. Censored data (overall survival) were estimated using the Kaplan-Meier method. The 5- and 10-year survival rates are presented with their 95% confidence intervals (CIs).