Clinical Study On The Relationship Between Cardiac Exposure Volume Dose And Radiation-induced Cardiac Injury In Patients With Coronary Heart Disease

ObjectiveThrough the retrospective study of chest radiotherapy in patients with coronary heart disease(CHD),clarify the effect of chest radiotherapy on heart in patients with coronary heart disease(CHD),and explore the relationship between the patients’ own factors and the physical factors of radiotherapy in the occurrence of radiation-induced cardiac injury.To explore the predictive value of cardiac limit of chest radiotherapy,symptoms and electrocardiogram(ECG)in patients with coronary heart disease(CHD).MethodCollected the patients who had been treated with chest radiotherapy in Qingdao University affiliated Hospital from June 2017 to June 2018.The patients who met the Diagnostic criteria for Coronary Atherosclerotic Heart Disease(WS 319 ≥ 2010)and received whole course radiotherapy were screened out,ECOG score 0 to 1,and the follow-up data met the requirements of this study.Patients with cardiac metastasis,patients with cardiomyopathy and valvular heart disease,patients undergoing coronary stent implantation or coronary artery bypass grafting,patients with incomplete follow-up data were excluded.Sequential or concurrent radiotherapy and chemotherapy have no affection selection.All patients signed informed consent before radiotherapy,the patient took supine position,the radiotherapy technician fixed the patient with thermoplastic fixation membrane,and CT scan was performed,after that,the radiologist outlined the target area and endangered organs.Than determined the prescription dose and the dose limit for endangering organs.Physicists made radiotherapy plans,verified the plan and started the radiotherapy.All patients used conventional radiation: five times a week,Saturday and Sunday rest.Depending on the patient’s condition,some patients were treated with synchronous or sequential chemotherapy.Collect patient case data,including: age,sex,tumor location,whether to accept regular coronary heart disease treatment in accordance with the will of cardiovascular physicians.The ventricular diameter was measured by echocardiography before radiotherapy and 3 months after radiotherapy.(Ventricular diameter,end-diastolic diameter,atrial diameter,left ventricular ejection fraction,cardiac output were measured to evaluate cardiac function,valve and so on.);electrocardiogram after 10 times of radiotherapy;whether the patient developed cardiac discomfort symptoms during radiotherapy(chest tightness,chest pain,panic).The parameters related to cardiac DVH were recorded,including the average cardiac dose expressed as MHD.The equivalentvolume dose of cardiac 1/3 is expressed as D1/3.And used V5,V10,V15,V20,V25,V30,V35,V40,V45,V50 respectively represented the heart volume as a percentage of the total heart volume exposed to the dose above 5Gy,10 Gy,15Gy,20 Gy,25Gy,30 Gy,V25,V30,V35,V40,V45,V50,35 Gy,40Gy,45 Gy,50Gy.The patients were evaluated according to the diagnostic criteria for radiation-induced cardiac injury(GBZ 241 ≤ 2012).SPSS 22.0 software was used for data analysis and statistical processing.ResultOf the 34 patients included,11 had radiation-induced cardiac injury,with an incidence of 32%.There was no significant difference in age,sex and tumor location between radiation-induced heart injury group and non-radiation-induced heart injury group(P > 0.05).However,the incidence of radiation heart injury in the non-coronary heart disease standard treatment group was significantly higher than that in the coronary heart disease standard treatment group(p < 0.009).The incidence of radiation heart injury in the treatment group was 15%,and that in the non-treatment group was 15%.The incidence of radiation-induced heart injury was 42.9%.The results of Mann-Whitney Fisher exact test showed that there were significant differences in the following physical parameters: V30-V45 and D1/3between the cardiac injury group and the non-radiation cardiac injury group(P < 0.01).The results of Logistic regression multivariate analysis showed that treatment and V30 were independent risk factors for radiation-induced cardiac injury.The incidence of radiation-induced cardiac injury in V30 ≤ 20%,20 < V30 ≤ 30% and V30 > 30% were 18%,36% and 45%,respectively.The incidence of radiation-induced cardiac injury in treated patients was 28% lower than that in untreated patients.The receiver operating characteristic curve confirmed that V30 could predict the occurrence of radiation-induced cardiac injury with moderate accuracy.There was no significant difference in chi-square analysis of whether the symptoms were positive or not(P ≤ 0.659),and the symptoms had no predictive value for radiation-induced cardiac injury.After nearly 10 times of radiotherapy,the incidence of radiation-induced cardiac injury was 50% in patients with ECG changes and16.67% in patients without ECG changes,the difference was statistically significant(P ≤0.036).That electrocardiogram(ECG)taken in nearly 10 times of radiotherapy has predictive value for radiation-induced cardiac injury.ConclusionThe main results are as follows1)In the process of chest radiotherapy,taking regular treatment follow the cardiovascular physicians,can effectively reduce the incidence of radiation-induced cardiac injury.According to this study,the incidence of radiation-induced cardiac injury can be reduced by about 28%.2)The incidence of radiation-induced cardiac injury was 18%,36% and 45% in V30 ≤20%,20 < V30 ≤ 30% and V30 > 30%,respectively,which could be predicted by chest radiotherapy dose-limited V30 in patients with coronary heart disease(CHD),and the incidence of radiation-induced cardiac injury was 18%,36% and 45%,respectively.Controlling the exposure dose of V30 can effectively reduce the occurrence of radiation-induced cardiac injury.3)For patients with coronary heart disease,the occurrence of radiation-induced cardiac injury can’t be judged by whether there are symptoms such as chest tightness,chest pain and panic,or whether the patients are aware of the aggravation of the above symptoms.The absence of symptoms or symptoms in the patient is not significant and does not represent the occurrence of radiation-free heart injury in the patient.Electrocardiogram(ECG)was performed in patients with coronary heart disease during radiotherapy.The incidence of radiation-induced cardiac injury was 50% in patients with ECG change and 16.67% in patients without ECG change.The incidence of radiation-induced cardiac injury was 16.67%.ECG examination was performed nearly 10 times after radiotherapy.It has predictive value for radiation-induced cardiac injury and can guide clinical treatment.