O. D. Bazyka, D. O. Belyi
State Institution «National Research Center for Radiation Medicine of the National Academy of Medical Sciences of Ukraine», Melnykova str., 53, Kyiv, 04050, Ukraine
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 sickness (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 examination, 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 systolic 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 geometry or its concentric remodeling was observed.
Conclusions. The CW and non-irradiated persons differed significantly by the onset of HHD and CHD, which previously developed in the CW, including the ARS survivors. Changes in the structural and functional state of myocardium 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 concentric hypertrophy.
Key words: clean-up workers of the accident at the Chernobyl nuclear power plant, ionizing radiation, hypertensive heart disease, coronary heart disease, left ventricular systolic dysfunction, myocardial hypertrophy.
Problems of radiation medicine and radiobiology. 2017;22:292–305.
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