Mitral valvuloplasty has been a challenging endocardial valvuloplasty technique for cardiac surgeons, and because of the complexity of the mitral valve structure, mitral valvuloplasty many times requires more technical improvements, and the success of mitral valvuloplasty is especially important for small infants and children who cannot undergo valve replacement and do not require long-term anticoagulation, no artificial materials, and rapid recovery of pediatric cardiac function as long as the valvuloplasty results are good [1]. A modified technique for pediatric mitral valvuloplasty was performed at our institution, and this article retrospectively summarizes the postoperative outcomes. Data and methods A total of 106 cases of pediatric congenital heart disease combined with moderate to severe mitral regurgitation were admitted to our hospital from March 1999 to December 2009 for modified mitral valvuloplasty, excluding patients with mitral valve replacement, mitral regurgitation due to left coronary artery originating from the pulmonary artery or dilated cardiomyopathy, and complete atrioventricular access. Small infants generally have surgical intervention in principle for all symptomatic ones. Mitral stenosis is predominantly treated surgically only if there are symptoms. In this group, there were 69 males and 37 females, aged 0.4-8.5 years (mean 2.2±1.8) and weighing 6.6-52 Kg (mean 10±3.5 Kg). The left ventricular function was assessed by ultrasound before surgery, and there were 16 cases of left ventricular dysfunction, and the left ventricular ejection fraction was above 55-60% after the use of cardiopulmonary diuresis and reexamination before surgery. According to the literature, different age groups have different plastic surgery methods [1], and our group was also divided into three groups according to age: 16 cases under 6 months in group A; 51 cases from 6 months to 2 years in group B; and 39 cases from 2 years to 8.5 years in group C. In addition, there were 8 cases of combined mitral stenosis, including 3 cases of parachute like, 3 cases of single papillary muscle, 2 cases of thickened and shortened tendon cords or shortened papillary muscle and fibrosis, including 3 cases of severe mitral stenosis (MS) (differential pressure >15 mm Hg) and 4 cases of moderate (differential pressure 10-15 mm Hg), and all of those with severe MS had pulmonary hypertension PAP was 51±8 mm Hg (45C100 mm Hg ) . The malformations that were also corrected were complex intracardiac malformations in 25 cases, such as ventricular septal defect, arteriovenous insufficiency, aortic valve, and tricuspid valve lesions. Preoperative 2D Doppler ultrasound was performed in all cases, and 69 cardiac catheterizations and cardiovascular angiograms showed that organic pulmonary hypertension was excluded. Preoperative valve evaluation was classified in three ways: hemodynamic, functional status, and anatomic differences. The anatomic situation is divided into the valvular dysplasia type, which tends to have a large left-to-right shunt to annular enlargement or papillary muscle prolongation, and the nonvalvular dysplasia type, which tends to have a lack of or poorly distributed leaflet tissue, and hemodynamics that can be predominantly regurgitant or predominantly stenotic or both or neither. The anatomic malformations in this order were: enlarged annulus without valve dysplasia in 43 cases, anterior leaflet prolapse in 33 cases, posterior leaflet prolapse in 11 cases, posterior leaflet restriction in 8 cases, anterior leaflet fissure in 3 cases, papillary muscle fusion in 3 cases, parachute like in 2 cases, and posterior valve dysplasia in 3 cases. The indication for preoperative surgery was the presence of severe mitral regurgitation that affected cardiac function. In all cases, the procedure was performed under mild or moderate hypothermic extracorporeal circulation (anal temperature 28°C to 32°C) with warm perfusion of myocardial protective fluid, and the surgical approach was determined by exposing the mitral annulus, leaflet structures, tendon cords, and papillary muscles through an atrial septal transection via an atrial sulcus or right atrial incision, with particular attention to the supravalvular annulus, leaflet motion, and location of the papillary muscles, and preoperative and postoperative exploration of the diameter of the valve orifice, according to The normal mitral orifice diameter is calculated based on the child’s weight and body surface area [2]. The principle of using one’s own tissue as much as possible during surgery reduces the use of artificial materials. Because of the complexity of the valve structure, different plastic techniques may be used in the same patient, using 5-0 to 7-0 prolene sutures and, if necessary, untreated own pericardial spacers to reinforce the annular tissue. In small infants younger than 6 months of age in group A, especially those with larger annuli, a modified Kay-Wooler annuloplasty is used, in which the circumference of the annulus is reduced with one stitch of prolene suture with pericardial spacers at the anteromedial and posterolateral junction of the annulus, respectively (see Figure 1). In small infants older than 6 months of age with a larger annulus in groups B and C of MR, we chose a modified Paneth annular reduction method in which the diameter of the mitral valve is converted to the corresponding mitral valve diameter according to the weight and height of the child, and the untreated pericardium is cut into different “C” rings and sutured with a padded 5-0 prolene suture. The posterior valve is sutured briefly to the posterior valve and the posterior annulus is annulated to the intersection of the two annuli (see Figure 2). In cases of severe posterior valve dysplasia, a modified Gerbode method is used, in which the annulus and leaflets of the posterior valve are interrupted by a “V”-shaped annulus with untreated pericardial spacers, and then reinforced with untreated pericardial strips interrupted on the annulus to the junction of the two valves after the annulus has been shaped (see Figure 3). For papillary muscle fusion and “parachute” mitral valves, the papillary muscle and ventricular wall were split twice during surgery to ensure that the newly formed papillary muscle and ventricular wall had sufficient muscle tissue to maintain function and that the newly formed papillary muscle was of adequate thickness. In 4 patients, an artificial ring was used to reduce the mitral annulus; in 3 cases, the mitral cleft was directly sutured, and in 7 cases with significant posterior valve dysplasia, a pericardial slice was used to enlarge the leaflet tissue, increase anterior and posterior leaflet alignment, and reduce regurgitation. After intraoperative plastic surgery, all cases showed mild regurgitation by water injection test, and esophageal echocardiography was performed before stopping extracorporeal circulation after aortic opening, which showed 15 cases of mild to moderate regurgitation, including 3 cases in group A; 8 cases in group B; and 4 cases in group C. Four cases of moderate regurgitation, including 2 cases in group A; 2 cases in group B, and the rest were below mild regurgitation. Results Early death (during hospitalization) was observed in 3 cases (2.8%). 2 cases were children in group A, who died on postoperative day 6-9 due to left heart failure caused by the aggravation of mitral regurgitation after surgery, and 1 case was a child in group B, who died on postoperative day 3 due to severe pulmonary hypertension and low cardiac output after surgery. The surviving children had a postoperative ventilator-assisted time of 28 to 129 hours (mean 56±3.5) and a postoperative left atrial pressure of 1.2 to 1.8 Kpa (mean 1.5±0.5). The duration of ICU stay ranged from 3 to 19 days. The echocardiogram of the surviving children before discharge showed mild to moderate reflux in 13 cases, including 3 cases in group A, 8 cases in group B, and 4 cases in group C. The remaining children in groups A, B, and C were discharged from the ICU. The rest of the children in groups A, B, and C had less than mild reflux. Three children with mitral regurgitation changed from mild to moderate regurgitation at 3 months to 3 years of follow-up; one of the two cases with moderate regurgitation in group B became severe, with poor cardiac function and 46% EF, and underwent valve replacement with good results; the other case with moderate regurgitation is still under follow-up, and there is no trend of aggravation of the regurgitation. Discussion Although the revision of valves in infancy is challenging because of their size, immature and fragile leaflets, and concomitant malformations, we believe that revision of valves is still needed. The reported outcome survival rate in our group is at 97.6%, which is similar to that reported in the literature [2-3]. The effect of mitral valvuloplasty is to establish a mitral valve function that is not optimal but as satisfactory as possible, rather than to construct a normal mitral valve structure [3]; or to delay or reduce the likelihood of subsequent valve replacement. The key is preoperative assessment of the structure of the valve malformation and the mechanisms that lead to valve stenosis and regurgitation. In our group, we have reported valve annulus enlargement and leaflet prolapse, and we believe that we should try not to place a rigid foreign interference ring, which can cause coagulation, bleeding, valve writing tissue growth, or left ventricular outflow tract obstruction on one side [4]. The method of surgical plastic surgery does vary by age [1], and we believe that pediatric valvuloplasty is based on annuloplasty, especially for those with enlarged rings, and for children under 6 months of age for annuloplasty of both junctions is appropriate, while children over 6 months of age can do most of the annuloplasty of the posterior flap as well. It is also believed that the C-ring is suitable for those over 2 years of age, otherwise about 25% of patients have residual MR after 5 years [5], but some authors believe that mitral valvuloplasty does not require any ring, but can do valvuloplasty [6], and our group has done many patients with mitral junction or posterior annulus annuloplasty, with very satisfactory results. In particular, we used our own pericardial piece to make a “C” shaped ring to reinforce the affected posterior valve to both valve junctions such as Kay-Wooler, Paneth, and Gerbode often, and the results were most satisfactory. It has been reported that the mitral valve does not do annular reduction, and the recurrence rate is higher after surgery [7], in valvuloplasty, the expansion of the leaflet tissue has dysplasia for the leaflet tissue, plus the free edge of the enlarged leaflet by the pericardial tissue, the glutaraldehyde fixed treatment of its own pericardial piece is easy to dissolve with its own leaflet tissue. The key is to separate the papillary muscle from the ventricular wall, and the papillary muscle and tendon are relatively free. The mortality rate of mitral stenosis is reported to be high, including parachute-like, and the key to reconstruction is to separate the leaflets, valve junctions, and openings. The intraoperative mitral valve opening meets the minimum diameter required by the physiology of the child to avoid postoperative mitral stenosis and to achieve a balance between mitral stenosis and mitral regurgitation [8-9]. Supravalvular mitral annulus occurs from time to time and should be treated together; although recurrence has been reported, the likelihood of supravalvular annulus is very low. We believe that the age less than 3 months, the degree of urgency of the procedure, the correction of the combined malformation, the duration of the procedure, and the structure and condition of the valve are factors influencing the prognosis of the procedure. The goal of pediatric mitral valvuloplasty is to prolong or eliminate the possibility of later valve replacement without lifelong anticoagulant medication. It is possible to wait until the age at which the valve should be replaced and perform the valve replacement surgery [10-11]. In conclusion, it is feasible for pediatric mitral regurgitation to be rectified, especially the modified method, to extend the time of valve replacement, and early rectification is effective, especially for patients with combined mitral stenosis, early rectification valve development is still possible, reoperation rate is relatively low, and early intervention can reduce damage to the valve. However, if mitral regurgitation is combined with a small annulus [12-13], the surgical difficulty will increase.