Congenital aortic valve lesions can be divided into two main categories: aortic stenosis and aortic valve closure insufficiency. There are more reports in the literature about the treatment of aortic stenosis. However, there are fewer reports on the treatment of aortic valve insufficiency, and almost no book presents congenital aortic valve insufficiency as a separate chapter.
There are four main causes of congenital aortic valve insufficiency: aortic valvular diastasis, aortic valvular tetralogy, aortic monovalvular diastasis, and ventricular septal defect combined with aortic valve insufficiency. Other causes include post-op aortic stenoplasty, incomplete closure including after percutaneous balloon dilation, and incomplete closure due to subvalvular stenosis impact. The management of these four conditions is highlighted.
1.Aortic valvular diastolic malformation
Aortic valve divalvular malformation refers to the aortic valve visible as two basically normal valve junctions, a counter-edge, one side is a fusion valve, mostly left and right coronary valve fusion, followed by the right without fusion, and the other side is nearly normal for the reference valve. Unlike normal valves, which each account for 33% of the annulus, valvular malformations account for 55% of large valves and 45% of small valves, and occasionally two valves can be symmetrical, which accounts for about 2% of valvular malformations.
The incidence of valvular malformations in the population is about 1-2%, and most patients have no lifelong valve problems. Another 15% to 20% of patients present with aortic insufficiency (AI), which is mostly due to fused leaflet congestion, and 57% of these AI patients can be repaired.
There are two types of shaping concepts: two-valve tricuspidation and two-valve based shaping.
First, we introduce trivalvularization treatment by cutting the fusion junction and reconstructing the leaflet and junction with autologous pericardium. Generally, the length of the autologous pericardium is greater than 15% of the aortic diameter, and the height is greater than 5 mm of the normal counterclockwise margin.
The unsatisfactory efficacy from the follow-up results may be related to the difficulty of this technique that requires simultaneous consideration of all three counterparts, so the techniques nowadays tend to reduce the aortic counterparts on the margins.
Secondly, the technique of “one counter-edge” plication, which is based on two flaps. The key to the success of this technique is that one of the two leaflets should be close to normal, that is, the reference cusp should be nearly normal, and the fusion leaflet should be long enough.
The reference cusp is essentially normal when the effective height of the leaflet (vertical height from the flap edge to the annulus) is >8 mm, or at least >5 mm, compared with 8-10 mm in normal subjects, or when the reference cusp is abnormal but can be restored to the essentially normal category with a simple repair. This includes: for fusion flap repair the first step is to identify the regurgitant opening and pin out the regurgitant opening by interrupted sutures, while increasing the effective height of the flap leaflet, eventually achieving the same length and height of both flap margins.
When there are too many prolapsed flaps, wedge resection can be used, but the sturdy suture edge should be preserved, otherwise the durability of the flap after repair will be affected. If the fusion ridge has significant calcification, it can be used as a moderately wide excision and repaired with a small triangular pericardial piece.
When the fusion flap leaflets are not long enough, shaping is generally not recommended and an overfolding technique may be used as a last resort.
For junctional separation, junctional folding can be used, emphasizing the need for simultaneous reinforcement with figure-of-eight sutures at the folded junctional flap edge; for junctional misalignment, junctional folding can also be corrected by junctional folding techniques, with figure-of-eight suture reinforcement at the folded junctional flap edge; for cases with normal annulus size and sinus diameter <45 mm, but sinotubular junction >40 mm, a segment of the artificial vessel can be replaced at the sinotubular junction. For cases with normal annulus size, sinus diameter >45 mm, and sinotubular junction >40 mm, ascending aortoplasty can be performed along with aortoplasty or repair of the ascending aorta with the Remodling technique.
Results.
1, 70% of AI can be formed
2. The criteria for leaving the operating room were: small amount of aortic regurgitation, peak pressure < 30, and mean pressure < 15, which was acceptable.
3.The 10-year reoperation rate is generally around 20%, and half of the failed implantations will occur in the first year after surgery.
The 5-year freedom from reoperation (with moderate aortic regurgitation) varies from 91% to 96%. Symmetric prolapse of the aortic leaflets is the main cause of reoperation.
2, Aortic valve quadruple valvular malformation
The incidence of aortic quadruple valve malformation is very low, 0.1‰- 0.3‰. The morphology of the four valves can be divided into as many as seven types, of which four equally sized leaflets, three equally sized large leaflets + one small leaflet, and two large leaflets + two small leaflets account for 85% of the total number of malformations; the most likely location for redundant leaflets is between the right uncoronary valve and between the right and left coronary valves.
In childhood and adolescence, there is often no indication of abnormal leaflet function; as we age, aortic valve insufficiency gradually develops due to thickening of the leaflet fibers as a result of leaflet dysplasia.
When patients with quadruple valvular aortic malformation present with mid to massive aortic regurgitation, surgical treatment needs to be considered. The vast majority of patients require aortic valve replacement surgery, and only a minority of patients can undergo aortic valvuloplasty repair. The concept of valvuloplasty is to make three leaflets out of four. Specific techniques include fusion of the small valve leaflets with the adjacent leaflets and junctional folding.
3.Univalved aortic malformation
There are usually two types reported in the literature: a single junction type and a junctionless type. The junction of the single-junction type is almost always located at the junction of the left uncrowned valve, while the fusion of the right and left valves and the right uncrowned valve occurs, and this type is more common; the junctionless type of the valve is generally vaulted, and sometimes traces of the junction are visible at the level of the valve opening. Unilobar malformations are present at birth with aortic stenosis and, in a few cases, with aortic regurgitation.
Mono-junctional types can undergo aortic valvuloplasty by means of mono-valvular bivalvularization: by incising the right non-junctional to make the mono-valve bivalve.
This is done by cutting the leaflet along the fused edge of the single valve leaflet to the level of the annulus, then extending 5-10 mm to either side along the annulus and repairing the cut leaflet with an autologous pericardial widening to reconstruct the valve edge and junction.
One paper reported 20 patients with intraoperative ultrasound findings: 19 patients had minimal postoperative aortic regurgitation; at 4 to 47 months of follow-up, only 1 patient had reoperation for AI at 3 years postoperatively, and the other patients had essentially stable aortic valve function. the chance of avoiding more than moderate aortic regurgitation at 4 years was 77%, the chance of avoiding reoperation was 67%, and the chance of avoiding valve replacement was 100%.
4.Ventricular defect combined with AI
The incidence of ventricular defect combined with aortic valve prolapse is about 5%, mostly in cases of outflow tract septal defect, with the most common being sub-stem type defects. Ventricular defects are mainly medium-sized ventricular defects larger than 5 mm, and less than 5 mm and huge ventricular defects occur less frequently.
The mechanism of occurrence: firstly, the tissue structure is missing and the corresponding support is missing at the level of the aortic annulus; secondly, the hemodynamic effect: the “Venturi effect”, due to the presence of the ventricular defect, leads to the presence of a left-to-right fast flow under the aortic valve, which can cause the associated aortic valve leaflets to drift in the direction of the same blood flow .
Clinically, it can be divided into 3 phases.
1, aortic valve prolapse phase
2.Reversible aortic valve closure insufficiency phase
3, irreversible aortic valve closure insufficiency phase
Aortic valve prolapse phase: Because the Valsalva sinus wall lacks the corresponding anatomic support, each cardiac systole pushes the corresponding structure to the right, which leads to dilatation of the aortic annulus and leaflet prolapse, but no significant aortic valve closure insufficiency occurs.
Reversible aortic valve insufficiency: As the disease progresses, mild regurgitation of the aortic valve begins to occur due to the lengthening of the aortic valve counter-edge and the “Venturi effect”; however, this regurgitation is reversible and will disappear if the ventricular defect is repaired in a timely manner.
Irreversible aortic valve closure insufficiency stage: the disease further progresses, diastolic pressure prompts further aggravation of the prolapsed valve leaflet prolapse and adhesions with the fibrous tissue around the ventricular defect, serious changes in the leaflet structure, the aortic sinus and annulus will be further enlarged, at this time the simple repair of the ventricular defect cannot solve the problem of aortic valve closure insufficiency.
From clinical staging we can find that ventricular defects in the neonatal period are almost never combined with AI, and the risk of aortic regurgitation increases gradually in childhood with the adverse hemodynamic effects on the aortic valve due to ventricular defects, with the peak of regurgitation generally occurring around 5 to 10 years of age. Therefore, early surgery can prevent the development of AR.