UDC 616.132-007.271-053.31-089.844
RESULTS OF AORTIC VALVULOPLASTY IN NEONATES WITH CRITICAL AORTIC STENOSIS
Chornenka I., Rudenko N., Maksimenko A., Yemets I.
Ukrainian Children's Cardiac Center, Kyiv, Ukraine.
The article discusses the results of treatment of critical aortic stenosis in 23 patients aged under 1 month. The main methods of treatment  is commissurotomy. All operated patients survived. The follow-up is 23,4 ± 15,5 months. Today the contractile ability of myocardium, in all patients, who are observed, is maintained (ejection fraction 68 ± 1,7%), average aortic valve gradient 23 ± 15,6. Freedom from re-operation in the remote period -89.5% and survival - 90.5%. So surgical valvuloplasty - is an effective treatment of aortic stenosis in the neonates with good immediate and remote results.
Keywords: aortic stenosis, surgical aortic valvulotomy, neonates.
Introduction. In 1956 Lillehei et al. offered valvulotomy of aortic valve (AV) under cardiopulmonary bypass (CPB). [1] This approach remained the gold standard of treatment of AV stenosis almost 30 years, till 1983 when Lababidi described a new technique - the use of balloon valvulotomy at the University of Missouri. [2] About 10 years this method had been prevailing. However, since the 90s, due to the accumulation of long-term results of both methods, the approach to the treatment of aortic stenosis (AS) became selective. Even today, despite the considerable experience of different clinics, there are no clear criteria for selecting of one method or another, especially for newborns and infants.
Aortic stenosis in this population of patients is characterized by high variability and can be combined with the hypoplasia of the valvular ring and  multiple left heart obstructive lesions. Depending of the anatomy of desease different surgical operations  can be made: aortic valvuloplasty, Ross and Ross-Konno procedures, DKS, aortic valve can be replaced by donor allograft or pulmonary autograft, by xenograft, by autologous valve made from own tissue or by valve made by the method of tissue engineering. However, from the above listed operations, only aortic valvuloplasty remain its own aortic valve, enables for further growth, give a long period between the reoperations and sometimes completely eliminates the need for repeat interventions, does not require anticoagulation. 
International experience over the past 10 years has shown that the  surgical valvulotomy is  the operation of choice for the young children. [3,4,5,6,7] 
This approach is chosen by our Center as well.
The purpose of the work. Analyzing of our own experience of surgical treatment of critical aortic stenosis in neonates.
Material and methods. During the period from 2011 to 2015 the open aortic valvuloplasty was made in 23 patients aged under 1 month of life, with critical or severe aortic stenosis. 
Thirteen patients were delivered to the hospital with ambulance, in 3 of them were  diagnosed prenatally, 1 patient required preoperative balloon valvuloplasty due to critical condition.
The age of the group of patients was 13 ± 8.6 days (from 1 day to 28 days), the weight was 4,5 ± 1,8 kg (from 0.39 to 4.6 kg).
The study include patients with such additional heart disease: mitral insufficiency (MI), patent ductus arteriosus (PDA),  patent foramen ovale (PFO), pulmonary artery stenosis (SP), abnormal vein between the left atrium and v. anonyma, dysplasia of the tricuspid valve (TV dysplasia). Comorbidity in amount of patients included: MI-3, PFO + PDA-4, MI + PFO-1, MI + PDA-1.
All patients on preoperative stage were given two-dimensional echocardiography. Before surgery, the average gradient on aortic valve was 43,7 ± 19,4 mm Hg., peak gradient was 76,2 ± 27,9 mm Hg. In 1 patients with reduced left ventricular function (ejection fraction (EF) less than 45%), the average peak gradient was 11, and maximum peak gradient was 43. In 21 patients the EF was preserved (EF 65,8 ± 16,4%).
Indications for surgery valvuloplasty or balloon valvuloplasty adopted in our Center are shown in Figure 1.

 Figure 1.
 The indications to the type of intervention in neonates and infants with aortic stenosis.

SAV- surgical aortic valvuloplasty, BAV- balloon aortic valvuloplasty, EF- ejection fraction, LV-left ventricle, Ao- aorta, mean- average value, peak- maximum, * -  with preserved ejection fraction.
There is no syndromic patients in this study group. Minimal aortic insufficiency before operation was diagnosed in 5 patients.
In 22 patients was done the primary surgical correction, in one -after balloon valvuloplasty, after 17 days. 
In all patients was done the surgical comisurotomy, in 11 of them was cut off the raphe, additionally the plasty of leaflets with autopericardium was made in 2: in one patient after balloon valvuloplasty (rupture of leaflet of  AoV was closed with the patch autopericardium) and in one patient primary was performed komisurotomy, after which was revealed the prolapse of right coronary leaflet, the leaflet was excised and formed a new one with autopericardium.
The CPB time was 75 minutes (from 47 min. to 365 min.), the time of aortic cross-clamp was - 41 minutes (from 23 min. to 57 min.).
According to the reports of operation functionally monocuspid valve was in 6 (26%) patients, bicuspid - in 14 (60.9%), tricuspid - in 3 (13%). The causes of stenosis which was found during the operation were coalescence together (with the presence of one or two raphes) of the leaflets of the valve in all patients, and in 14 (60.9%) of them were marked fibrosis and myxomatous thickening of the AV leaflets.
All 23 patients which were operated, survived. Stable condition and routine postoperative recovery were observed in fifteen patients. The median time of ventilation after surgery was 33 hours (from 10 hrs. to 304 hrs.). The median time spent on intensive care was 5 days (from 3 days to 54 days). According to ECHO cardiography, which was performed within 24 hours of surgery, EF was 60 ± 14%, average gradient on aortic valve decreased from 43.7 ± 19.4 mm Hg. to 17 ± 9.2 mm Hg., aortic valve insufficiency after surgery in 10 patients was minimal and in one was moderate.Postoperative complications were diagnosed in 8 patients (2 diaphragmatic paresis, requiring surgical placation, 2 bleedings, requiring revision of postoperative, in 1 - chilothorax that required surgical intervention, in 2 - arrhythmias and in 2 - delayed sternal closure).

In the remote postoperative period within 23,4 ± 15,5 months (from 1 month to 50 month) 21 (91.3%) patients were observed, 2 patients were lost. Today, in all observable patients contractile ability of myocardium is  maintained (EF 68 ± 1,7%). Aortic valve insufficiency: in 9 patients - minimal, in 4 - moderate. Average gradient in aortic valve - 23 ± 15.6 mm Hg.
In the remote period, two patients in 8.53 and 6.8 months after surgery, have required re-intervention because of aortic valve restenosis. For one of them repeated surgical valvuloplasty was made, for another one - DKS. In the first patient today (39 months follow-up after the last operation) observed moderate aortic valve insufficiency with 25 mm Hg. average gradient, to another has already made Glenn operation. In the remote period 2 patients died: after 12.5 months and 18.5 months after the first operation. The cause of death of patients was cardiopulmonary insufficiency which developed in one  due to infection, and in other - because of comorbidity - stenosis of the pulmonary artery, significant stenosis of the pulmonary artery branches (with severe stenosis of lobar branches), which required further operations and stent implantations, which have been ineffective.
Thus, freedom of reoperations during the observation (maximum 4 yearn 3month after surgery) was 89.5%, and the survival rate in the remote period was 90.5%.
Aortic valvuloplasty in neonates, in the most cases, is a multi-stage intervention and may require repeated future reinterventions. In patients with preserved left ventricular EF and without severe comorbidity good immediate and long-term results were observed. Good postoperative results were accepted in our Center are - preserved left ventricular EF, minimal aortic valve insufficiency (AI), aortic valve gradient no higher than 30 mm Hg.
In the vast majority of operated patients currently minimal AI was diagnosed and only one patient from the study group needs a surgery today because of restenosis of AV, confirming the good long-term results and correspond global experience.Thus, Siddiqui et al (2013) show the freedom from reoperation after surgery in 65% during the five-year period [3] and Agnoletti et al (2006) noted mortality in 19% after surgery for 6-year follow-up. [6 ]
Conclusions.
1.	Surgical valvuloplasty - is an effective treatment for AS in neonates with good immediate and remote results.
2.	This method requires further research in remote postoperative period with comparison of statistically significant group of patients for each specific procedure for selecting the method of surgical intervention and predicting outcomes.

Literature

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