UDC: 616.126.3-007.271-089/616.124.2
 
INFLUENCE OF AORTIC VALVE REPLACEMENT IN PATIENTS WITH CRITICAL AORTIC STENOSIS WITH PRONOUNCED CALCIFICATION ON PROCESSES LEFT VENTRICULAR REMODELING

A.Nikonenko, S. Nakonechnyi, V. Osaulenko, D. Polishchuk, A. Ponomarenko, R. Toriya, Y. Pluzhnik,  S.Pasudevskyi, S. Matveyev
Zaporozhye Medical Academy of Postgraduate Education
Ministry of Health of Ukraine

          This article presents the results of aortic valve replacement with aortic stenosis complicated by severe calcification in patients with preserved and reduced left ventricular ejection fraction at 6 months after surgery.
Analysis of the natural history of aortic stenosis showed that after the first symptoms of the disease within 2 years more than 50% of patients die[2]. The main causes of death are coronary insufficiency and cardiac arrhythmia [1]. The only radical treatment for aortic valve defect is surgical correction [5, 6].
Key words: Aortic valve, stenosis, surgery, echocardiography, remodeling

The purpose of study: To evaluate the process of left ventricular remodeling in patients with critical aortic stenosis (AV) before and 6 months after valve replacement.

Material and Methods. The study included 163 patients with cardiac surgery prosthetics of AV performed in cardiosurgery center on the basis of Municipal Institution Zaporozhye Regional Clinical Hospital  from 2009 till 2014. The average age of the patients was 62,3 ± 5,26 years (range 39 to 75 years): 112 men (68.7%) and 51 women (31.3%). All patients had heart failure corresponded III - IV functional class NYHA classification. Patients were divided into two groups according to the severity of the defect and ejection fraction (EF) of the left ventricle (LV). The first group included 67 (41.1%) patients with left ventricular ejection fraction less than 50%, the second one- 96 (58.9%) patients with left ventricular ejection fraction greater than 50%. Patients in both groups did not differ by age.
Before surgery all patients were performed by the research of intracardiac  hemodynamics by transthoracic echocardiography, the state of coronary arteries was assessed by coronarography.
Echocardiography was performed in one-two-dimensional, Doppler mode on the unit: En Visor C, US production. The following parameters: end-diastolic dimension (EDD), cm; end-diastolic volume (EDV), ml; end-systolic dimension (ESD), cm; end-systolic volume (ESV), ml; stroke volume (SV), ml; ejection fraction (EF),%; left ventricular myocardial mass (LVMM), g;  left ventricular myocardial mass index (LVMMI), g / m2; interventricular septum thickness in systole (IS), mm; the thickness of left ventricle posterior wall in systole (PWLV) mm; peak and average gradients at the aortic valve, mm Hg were evaluated.
The calculation of ejection fraction by Simpson equation was performed in hardware mode [3, 4]
The degree of mitral regurgitation was assessed by the percentage of the jet area and left atrium area [3].
Coronarography was performed according to  M.Judkins’ method (1967) with fixing images on angiographic complex "Semens" Acuson Artis.

Results and Discussion
The study included patients without any significant stenotic coronary involvements according to the  results of coronarography  that did not require additional shunt vessels.
Prior surgical treatment of the first group of patients, compared with those of the second group of patients, table 1, there was a significant increase in EDD, EDV, ESD, ESV, and SV of 8.1%, 6.3%, 7.0%, 4.3% and 8.7% respectively.
Significant increase in LVMM and LVMMI was revealed in patients of the first group of 7.2% and 7.0%, respectively.
Also, there was a decrease in LVEF of 6.9% in the first group compared to these indicators in the second group.
PWLV, IS thickness had no significant differences in both groups of patients.

Table 1.

Echocardiography in patients of the first and second groups before surgery (M ± m)

Indicator, unit of measure	First group, n=67 	Second group, n=96	
EDD LV, cm	7,02±0,28	5,62±0,15	
EDV LV, ml	257±24,0	155,0±6,0	
ESD LV, cm 	5,63±0,33	3,91±0,15	
ESV LV, ml	155,0±22,0	66,5±6,1	
SV LV, ml	102,0±1,01	88,5±3,3	
EF LV, %	39,6±2,80	57,1±1,30	
IS, cm	1,56±0,06	1,60±0,05	
PWLV, cm	1,40±0,05	1,40±0,05	
MMLV, gr	538,0±65,0	387,0±36,0	
IMMLV, gr/м2	269,0±0,33	188,0±17,0	
Pick gradient on AV, mmHg	93,7±21,4	88,1± 24,8	
Average gradient on AV, mmHg	51,2± 13,7	47,4±15,1	

By means of the continuous wave Doppler’s method maximum high peak and average pressure gradients between the aorta and the left ventricle were recorded in both groups of patients.
In all patients according to transthoracic echocardiography the mitral valve regurgitation was found. In the first group mitral regurgitation of III degree was detected in 19 (28.3%) patients, II degree - in 48 (71.7%). In the second group the third degree of regurgitation was revealed in 12 (12.5%) patients, the second degree – in 53 (55.2%) and the first degree of regurgitation - in 31 (32.3%) patients.
Aortic valve replacement was done for all patients. The double-leaf mechanical prostheses of  aortic valve ATS and SJM were used for replacement.
After 6 months after the operation, in patients of the first and second groups, compared with the data before the operation, there is a significant decrease in the performance of linear and volumetric LV, reduction of MMLV and IMMLV, increase of EF at 8.1% in the first group and 9.2% in patients of the second group.

Table 2.

Echocardiography in patients of the first group before and 6 months after surgery (M ± m)

Indicator, unit of measure	First group, n=67	
	Before the operation	After the operation, 
(6 months)	
EDD LV, cm	7,02±0,28	6,32±0,15	
EDV LV, ml	257±24,0	202,0±12,0	
ESD LV, cm	5,63±0,33	4,71±0,15	
ESV LV, ml	155,0±22,0	103,0±8,0	
SV LV, ml	102,0±1,01	99,0±4,01	
EF LV, %	39,6±2,80	49,1±1,10	
IS, cm	1,56±0,06	1,50±0,05	
PWLV, cm	1,40±0,05	1,35±0,05	
MMLV, gr	538,0±65,0	434,0±38,0	
IMMLV, gr/м2	269,0±0,33	213,0±19,00	
Pick gradient on AV, mmHg.	93,7±21,4	21,5±5,2	
Average gradient on AV, mmHg.	51,2± 13,7	11,6±3,3	

Table 3.

Echocardiography in patients of the second group before and 6 months after surgery (M ± m)

Indicator, unit of measure	Second group, n=96	
	Before the operation 	After the operation, 
(6 months)	
EDD LV, cm	5,62±0,15	5,26±0,16	
EDV LV, ml	155,0±6,0	133,0±9,0	
ESD LV, cm	3,91±0,15	3,51±0,20	
ESV LV, ml	66,5±6,1	51,0±7,5	
SV LV, ml	88,5±3,3	82,0±1,50	
EF LV, %	57,1±1,30	61,6±2,6	
IS, cm	1,60±0,05	1,50±0,05	
PWLV, cm	1,40±0,05	1,40±0,05	
MMLV, gr	387,0±36,0	333,0±15,0	
IMMLV, gr/м2	188,0±17,0	162,0±7,0	
Pick gradient on AV, mmHg.	88,1± 24,8	19,8±5,7	
Average gradient on AV, mmHg.	47,4±15,1	11,3± 3,7	

There’s a statistically significant reduction in the peak and average pressure gradient on the prosthesis AV, which demonstrates the effectiveness of surgical correction of the defect. Reducing the pressure in the left ventricle resulted in decreasing the degree of mitral regurgitation, which after 6 months in both groups did not exceed the first-second degree.
Thus, the results indicate more severe violations of structural - geometric and functional parameters of the left ventricle before surgery in patients of the first group compared with those of the second group, as well as fairly significant decrease in linear and volumetric parameters of LV, reduction in MMLV and IMMLV, increasing EF 6 months after surgery.

Conclusions.

1.	Patients with aortic stenosis complicated by severe calcification, shows estimates of structural and geometric and functional parameters of left ventricular function, assessment of mitral valve regurgitation and the degree of the valve before and after surgery by transthoracic echocardiography.
2.	Dynamics of structural -  geometric and functional parameters of the left ventricle in patients of both groups in 6 months after prosthesis AV is characterized by a significant decrease of linear and volumetric parameters of LV, MMLV, increase of EF LV, decrease in the degree of regurgitation on mitral valve, which indicates the positive impact of operations on processes of reverse LV remodeling.

Literature

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