Cardiovascular diseases and systolic function of left ventricle in clean up workers of Chernobyl accident (based on 30 years follow up)

OBJECTIVE

To study the dynamics of circulatory system diseases during the 30 year period after irradiation, changes in the status of systolic function of heart left ventricle (LV) and the features of its remodeling in clean up workers (CW) of the accident at the Chernobyl nuclear power plant (ChNPP).

MATERIAL AND METHODS

It was examined 144 CW at ChNPP, including 52 patients, who survived acute radiation sick ness (ARS) grade of severity 1-3, and 105 non irradiated persons (control group - CG). CW have been divided into two subgroups: without signs of ARS (ARS0) and those who suffered from ARS. CW and CG patients were male who had no signs of cardiovascular, nervous, pulmonary or endocrine pathology prior to the Chernobyl accident. Their average age at the beginning of the accident was 33.9-37.7 years. The study program included clinical examina tion, echocardiography, retrospective and statistical analysis.

RESULTS

Hypertensive heart disease (HHD) has developed in the CW, including the ARS convalescents, by 12 years, and ischemic heart disease (CHD) at 9-11 years is believed to be earlier than in comparable non irradiated patients. In the post accident period, there was an increased mean value of LV posterior wall (PW) thickness, interventricular septum (IVS), myocardium mass and myocardium mass normalized by body surface area. These indices grew with the increase of HHD duration. Over the 30 year follow up period, between CW and CG from 14.3 to 28.6 % of patients with LV increased volumes it was found a decreased ejection fraction (EF), what indicated the development of sys tolic LV dysfunction with the phenomena of left ventricular heart failure (HF). Reduction of EF correlated with increase of end systolic volume (ESV) having the highest statistical strength. In CW and persons of CG there was from 77.3 to 84.8 % of patients had clinical signs of HF with preserved EF. From this number, 56-63.6 % of patients had concentric and 18.8-26.7 % had eccentric LV hypertrophy (LVH), and in 6.1 to 15.6% of patients, normal LV geom etry or its concentric remodeling was observed.

CONCLUSIONS

The CW and non irradiated persons differed significantly by the onset of HHD and CHD, which previ ously developed in the CW, including the ARS survivors. Changes in the structural and functional state of myocardi um during long term follow up did not have any probable differences between CW and non irradiated persons and consisted of BW and IVS thickening, which predetermined the development of LVH. In CW and CG concentric LVH was dominant. The LV systolic dysfunction with decreased EF and increased ESV was characterized by clinical symptoms of left ventricular HF. More than half of patients with clinical symptoms of HF and preserved EF had signs of concen tric hypertrophy.

RELATIVE TELOMERE LENGTH OF PERIPHERAL BLOOD LYMPHOCYTES AND STRUCTURAL AND FUNCTIONAL STATE OF THE LEFT VENTRICLE MYOCARDIUM IN CLEAN-UP WORKERS OF THE CHORNOBYL ACCIDENT WHO SUFFERED FROM STENOTIC CORONARY ATHEROSCLEROSIS

The objective was to analyze the relative telomere length (RTL) of peripheral blood lymphocytes depending onmyocardium structural and functional state in emergency workers (EW) of the Chornobyl accident who suffered fromcoronary arteries stenotic atherosclerosis.

MATERIALS AND METHODS

There were examined 60 male EW who operated at the Chornobyl nuclear power plant at1986 and 25 male non-irradiated persons (control group - CG) with coronary heart disease (CHD). Everyone EW andCG patients were almost healthy before the accident. During the period 2016-2021, they underwent a comprehen-sive clinical and laboratory examination, echodopplercardiographic examination and determination of RTL by fluo-rescent hybridization in situ using laser flow cytometry.

RESULTS

EW almost did not differ from CG according to its clinical characteristics, the presence of risk factors,indices of systolic and diastolic heart functions, as well as RTL. The analysis of variance showed that RTL was influ-enced by the fact of irradiation in combination with obesity (p = 0.020). At normal body weight, RTL average valuein CG was significantly higher than in EW (p = 0.023). According to the results of hierarchical cluster analysis of twovariables as RTL and end-diastolic volume normalized by body surface area (EDV/BSA), EW and CG patients togeth-er were divided into two subgroups. The first subgroup (1st cluster) differed from the second (2nd cluster) by signi-ficantly larger average values of left ventricle (LV) EDV and end-systolic volume (ESV) as well as EDV/BSA andESV/BSA, LV myocardial mass (MM) and MM/BSA, reduced ejection fraction (EF). In patients of the 1st cluster telom-eres were significantly shorter than in the 2nd one (10,3 ± 1.7 vs. 14.3 ± 2.0 at p = 0.000). The increase of myocar-dial mass and LV wall thickness caused the development of its hypertrophy. The number of people with hypertrophyLV was significantly higher among patients of the 1st cluster (91.6 vs. 67.2 %, p < 0.001) due to eccentric hypertro-phy LV. Accordingly, concentric hypertrophy LV was more common among patients in the 2nd cluster (24.6 vs. 4.2 %at p < 0.01). Patients of the 1st cluster was characterized by a more severe course of heart failure.

CONCLUSIONS

In patients who suffered from CHD with stenotic atherosclerosis of the coronary arteries and wereexposed to radiation 30-35 years earlier, having normal body weight, there was a reduction in telomere. Hierarchicalcluster analysis proved to be a good tool that allows by the value of RTL and EDV/BSA to separate the group ofpatients with the most severe clinical course of CHD and LV systolic dysfunction among patients with the samepathology.