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Muminov Shovkat Kadirovich, Tashkent Pediatric Medical Institute, Faculty assistant E-mail: mbshakur@mail.ru
STRUCTURAL-FUNCTIONAL VALUES OF THE LEFT CHAMBERS OF HEART IN THE ASPECT OF THE CONTRAST INDUCED NEPHROPATHY
Abstract: This research demonstrated that echoCG predictors of contrast induced nephropathy in patients with stable forms of ischemic heart disease were chamber dilatation (136 ml) and increase of the index of the left ventricle regional con-tractibility disorder (up to 1.2 points and above), decrease of E/A ratio of tissue dopplerogram of the lateral margin of mitral ring to 0.7 rel. units and less.In spite of the improvement of the index of regional contractibility disorder and the index of the left ventricle sphericity, after roentgen contrast endovascular procedures in the group of contrast induced nephropathy of the patients with ischemic heart disease there was more significant deterioration of the structural-functional characteristics of the left ventricle myocardium, which displayed in the increase of the value of systolic myocardial tension, decrease of ejaculation fraction, and increase of the degree of diastolic dysfunction, proving the toxic effect of contrast preparation not only in kidneys, but also in myocardium.
Keywords: ischemic heart disease, contrast induced nephropathy, cardiotoxicity of contrast media, structural and functional features of the left heart.
This research demonstrated that echoCG predictors of contrast induced nephropathy in patients with stable forms of ischemic heart disease were chamber dilatation (136 ml) and increase of the index of the left ventricle regional contractibility disorder (up to 1.2 points and above), decrease of E/A ratio of tissue dopplerogram of the lateral margin of mitral ring to 0.7 rel. units and less. In spite of the improvement of the index of regional contractibility disorder and the index of the left ventricle sphericity, after roentgen contrast endovascular procedures in the group of contrast induced nephropathy of the patients with ischemic heart disease there was more significant deterioration of the structural-functional characteristics of the left ventricle myocardium, which displayed in the increase of the value of systolic myocardial tension, decrease of ejaculation fraction, and increase of the degree of diastolic dysfunction, proving the toxic effect of contrast preparation not only in kidneys, but also in myocardium.
For many years IHD and its complications stay to be leading cause of death among adult population in the world, conditioning 7.2 mln deaths a year. That guaranteed topicality of the searching for the salvation of the problem ofradical treatment of IHD [1]. 1958 was the start of new era of implementation of roentgen contrast endovascular procedures (CEP) [2]. It is interesting that in the same year the first selective coronary angiography done to Mason Sons from Cleveland clinic was complicated by the development of ventricular fibrillation [3], and it made the history of intervention cardiology development to be the history of the study of unfavorable effects of contrast substance application. Though, the intervention cardiology, including balloon agioplastics, implantation of stents of various design, application of rot ablators and intravascular lasers [4; 5], progresses very fast, the problem of CEP safety is still topical one.
The number of the performed roentgen contrast procedures (CEP) is steadily growing. According to the data of European Register of intervention procedures, in Europe the number of the performed coronary angiographies within 2010-2015 increased to 13.91%, while therapeutic interventions (angioplastics, stenting, etc) increased to 25.76% [6]. Application of contrast substances is one of
the most important factors conditioning CEP complications due to nephrotoxicity. Since the moment of the first CEP application there were studies performed for understanding of pathologic physiology and design of preventive strategies in the aspect of contrast induced nephropathies (CIN) [7; 8]. Though the problem of cardiac toxicity of contrast media and the link between the processes ofmyocardium ischemic remodeling and risk of CIN development are not less topical.
The objective: to study structural-functional peculiarities of the left chambers of heart in patients with IHD dependently on the development of contrast induced nephropathy (CIN)endovascular procedures (CEP).
Materials and research methods. The research involved 303 patients with stables forms of IHD, hospitalized in the department of intervention cardiology of the Republican Specialized scientific Practical Medical Center of Therapy and Medical Rehabilitation for the performance of roentgen endovascular procedures (CEP). The average age of the patients was 53.79 ± 1.27 years; there were 212 men and 91 women, and that was equal to 70%and 30% of the total number of patients.The study did not include the patients with GFS below 60 ml per a minute determined according to serum concentration of creatinine. Inclusion criteria were also oncologic and autoimmune pathologies, glomerulonephritis, pyelonephritis, and infections of urinary ducts in exacerbation stages, uncontrollable arterial hypertension, blood pathologies, gout, allergic reactions to iodine and iodine containing preparations, chronic diseases demanding therapy during the research period, and patient's refusal to participate in the study. All patients involved in the study received a standard therapy of IHD for 3 months at the moment of the inclusion to the study. The control group included 20 healthy volunteers of the appropriate age without signs of the diseases of cardiovascular and urinary systems, including functional ones.
All patients with IHD involved in the research had coronary angiography with application of unihexone contrast substance. Angioplastics and stenting of coronary arteries were performed when there were indications (84.82%). Later at the 1, 2, 3, 5, 7, and 10th
Section 3. Medical science
days we performed dynamic definition of serum concentration of creatinine with calculation of the speed of glomerular filtration for the isolation of the patients who had CEP post operatively complicated by CIN. The present study CIN was defined as increase of the concentration of serum creatinine to 25% in twenty-four hours and later after CEP. According to the results of the study all patients were divided to 2 groups: patients with uncomplicated post operative CEP period (CIN-, 206 patients, 67.99%) and patients who had contrast induced nephropathy (CIN +, 97 patients, 32.01%). We performed retrospective comparison of CIN + and CIN - group according to echocardiographic parameters.
Echographic study (EchoCG) with the help ofultra sound sensor with 2.5-5MHz frequency and application of standard approaches and positions. The following parameters were registered: terminal diastolic volume of the LV (TDV LV) and terminal systolic volume of the LV (KCO AX) calculated according to Simpson's modified method; left atrium volume (LA); terminal systolic and diastolic sizes of LV; width of ventricular septum and the posterior wall of the left ventricle during diastole and systole; diameter of basal part of LV chamber and length of LV.
We performed spectral tissue dopplerography of the lateral margin of fibrous ring of mitral valve where we registered maximal speeds of diastolic shift of the fibrous ring of mitral valve in the stage of early and atrial fulfillment of the LV (E and A) and their correlation.
Reliability of comparisons between groups was performed using Student's criterion for pair and unpaired differences.
Results of the research and discussion. That research revealed that compared to the control group in patients with IHD structural-functional status of the left chambers of heart demonstrated proc-ceses of remodeling tending for formation of dilatation cardiomyopathy with ischemic genesis. For example, in case of global systolic function at the level of the lower normal border of TDV LV was significantly increased, as well as LV myocardial mass indexed to the square area of the body surface (iMMLV). The value of internal myocardial systolic stress was notably increased testifying pathological and not physiological remodeling.
LV geometry was also changed with a tendency for formation of sphere-like cavity (increase of the sphericity index), which in its turn decreased hem dynamic efficiency of myocardium, as the most effective one in the aspect of spiral ejaculation flow formation was cone shape characteristic for normal LV. Ischemic genesis of cardiomyopathy forming due to coronary artery conductibility disorder serves the basis for disorders of regional systolic myocardial function, and it was proven in that research by the increase of the index of regional contractibility disorder (IRCD). That phenomenon can be based both on post infarction cicatrix and hibernating myocardium, which preserves viability, but does not manifest contractive activity in the conditions of mitochondrial deficit and calcium resetting. Same processes of mitochondrial deficit and calcium resetting promote the increase of myocardial stiffness, the additional mechanism ofwhich is activation oflocal tissue RAAS. The result of myocardial stiffness increase was diastolic dysfunction determined in our research by means of tissue dopplerography of the lateral margin of the fibrous ring of mitral valve. Application of this method was conditioned by the fact that its results did not depend on preload, which was actual
for CIN, treatment of which was actually adequate rehydration of the patients. Indirect prove of diastolic dysfunction increasing the load on LA, was enlargement of LA in patients with IHD in comparison with the control (CG) (difference reliability of all described values with the CG p < 0.001).
Comparison of CIN+ and CIN- groups revealed that TDV and IRCD were reliably higher in CIN+ than in CIN- (p < 0.001 for both correlations); there was also greater diastolic dysfunction in CIN+ group (p < 0.01 compared to CIN-).
TDV medium was equal to 136ml; there were 153 patients with TDV less than 136ml, among them CIN developed in 37 (absolute risk 24%); there were 150 patients with TDV above 136ml, among them 60 had CIN (absolute risk 40). Thus, according to the results of our research the rise of TDV above 136 ml increased the risk of CIN 1.65 folds (relative risk of CIN with TDV above 136 ml compared with TDV below 136 ml: 40/24, x2 = 8.72, p < 0.01). For IRCD medium was 1.2 points; the absolute risk of CIN in patients with IRCD below 1.2 points was equal to 23% (32 out of 141); patients with IRCD 1.2 points and more had 40% (65 out of 162); relative risk of CIN in case of IRCD rise to 1.2 points and above in the patients with stable forms of IHD was 1.77 (x2 = 10.56, p <0.01). E/A medium was equal to 0.7rel.units; absolute risk of CIN in patients with E/A less than 0.7rel.units was 24% (34 out of 140), while in patients with E/A 0.7rel.units and less 39% (63 out of 163); relative risk of CIN in case of decrease of the speed of mitral ring lateral margin shift in early and late stages of diastole was less than 0.7 rel.units and was equal to 1.59 (x2 = 8.72, p < 0.01).
The aforesaid results correlate with reference data on the predisposition to the development of CIN in patients with symptoms of cardiac failure decompensation such as increased concentration of cerebral natrium diurrhetic peptide in peripheral blood [9,10], atrial fibrillation [11], cardiogenic shock [12], complicated myo-cardial infarction.
At the 10th day of the follow up after CEP patients involved in the study had statistically reliable, but clinically insignificant increase of iMMLV (to 0.73%, compared to original data p <0.01), decrease of the global systolic function (to 0.31%, p < 0.001), rise of internal myocardial tension (to 3.33%, p <0.001), decrease in E/A ratio of trans mitral flow (to 1.83%, p < 0.001), and LA enlargement (to 0.66%, p <0.001). Complex of all described alterations indicates deterioration of structural-functional status of the myocardium of the left chambers of heart, though the degree of these alterations is not clinically significant. Revealed negative effects of CEP on hem dynamics can be explained by cardiac toxic effects of iodine containing contrast substance. Possessing high osmolar value (5 times above blood osmolarity) the contrast substance causes cellular dehydration and ischemia, especially in originally ischemic myocardium. Clinically cardiac toxicity can be manifested in the symptoms of cardiac failure and ventricular tachyarrhythmia [13].
The trigger of the described process was possibly roentgen contrast substance. Though among the studied values there were shifts to positive side, probably linked to performance of coronary revascularization such as improvement (decrease) of the local contractibility of the LV IRCD (to 0.69%, p < 0.001) and sphericity index indicating the process of reverse remodeling of the LV (to 1.92%, p < 0.001).
Division to CIN+ and CIN- groups revealed that the value of internal myocardial tension in CIN+ group significantlyincreased (p < 0.001), while in CIN- group it was at the original level (p < 0.001) difference reliability of relative dynamics between the groups). Dynamics of the rest studied values of echoCG was similar in both groups. Thus, the research demonstrated the following: 1) EchoCG predictors of CIN in patients with stable forms of IHD are dilatation of LV chamber above 136ml (relative risk 1.65, p < 0.01), disorder of its regional contractibility (index of regional contractibility disorder 1.2 points and more, relative risk of CIN -
1.77, p < 0.01), and diastolic function (decrease of e/a ratio of tissue dopplerography of the lateral margin of mitral valve to 0.7 rel.units and less, relative risk of CIN 1.59, p < 0.01);
2) Patients with IHD after CEP had deterioration of structural-functional characteristics of LV myocardium more significant in CIN+ group, manifested in the increase of the value of systolic myocardial tension, decrease of FE of LV, and increase of the degree of diastolic dysfunction, in spite of the improvement of IRCD and LV sphericity index, testifying toxic effect of roentgen contrast substance on myocardium, parallel to renal dysfunction.
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