ABC | Volume 114, Nº5, May 2020

Statement Brazilian Cardiology Society Statement for Management of Pregnancy and Family Planning in Women with Heart Disease – 2020 Arq Bras Cardiol. 2020; 114(5):849-942 In contrast, during preconception, abnormal chronotropic response identified on ergometric test in women with heart disease seems to be predictive of adverse events during future pregnancies. In the same line of investigation, ergospirometry test is valid for evaluation of myocardial reserve, especially in women with congenital heart disease. 35 2.3.6. Key Points • ECG and echo should be indicated when heart disease is suspected; • Fetal echo is indicated for congenital heart disease or when fetal involvement is assumed due to maternal disease; • 24-hour Holter monitor assists in identification and stratification of cardiac arrhythmias; • The main indication for ABPM is identification of “early” arterial hypertension, which occurs during the first 20 of gestation; • Exercice testing is not indicated for investigation of ischemic coronary disease during gestation; • Ergospirometry testing assess to risk stratification for women with heart disease when planning gestation. 2.4. Ionizing Imaging Cardiovascular Assessment The use of ionizing imaging diagnosis in adult with heart disease corresponds to 12% of all examinations to which these patients are exposed 36 and to 40% of the total dose of radiation which they will receive during their lifetime. 37 For this reason, they are a cause of concern regarding the safety of examinations that emit radiation during pregnancy and lactation. Measurements of ionizing radiation may be in sieverts (Sv), which express the equivalent dose of radiation in the tissue, or in gray (Gy), which indicate total radiation dose. Sv is the measure of greatest biological significance. 38 There are two biological effects of radiation, namely, the deterministic effect, which leads to cell death when the maximum recommended dose of radiation is exceeded and which becomes evident after a few days, weeks, or months of the procedure (cataract, leukopenia, anemia, sterility, and others); and the stochastic effect, which causes cellular transformation with random alteration in single-cell DNA (deoxyribonucleic acid) that continues to reproduce. When the damage occurs in germ cells, genetic or hereditary effects may occur. There is no dose threshold, and damage may be caused by a minimal radiation dose. Moreover, the effects are difficult to measure experimentally due to the long latency period. The main examples include cancer (leukemia from 5 to 7 years, solid tumors from 5 to 10 years or more) and genetic effects. It has been verified that stochastic effects are highest in children and higher in women than in men, and they are reduced by 50% among octogenarian men. 39 During pregnancy, the biological effects of radiation on the embryo depend on dose and gestational age, and they may be divided into the following 4 categories: intrauterine death, malformations, growth and developmental disorders, and mutagenic and carcinogenic effects. 40,41 It is accepted that the non-carcinogenic risk, which includes miscarriage and malformations, is insignificant at doses below 50mGy, in comparison with other risks of pregnancy. In contrast, it is estimated 42 that doses above 100 mGy present potential effects on the fetus/embryo in accordance with gestational age, such as fetal death when exposure occurs between the first and second week of gestation; severe abnormalities in the central nervous system (hydrocephalus, microcephaly, and mental retardation) between weeks 3 and 15; mental retardation, microcephaly, and fetal growth restriction between weeks 16 and 30; following week 32 of gestation, teratogenic effects are absent, but there continues to be an increased risk of developing malignancy during childhood and adulthood. Indication for interrupting gestation may be considered in cases of radiation doses between 100 and 500 mGy, based on individual circumstances, such as maternal malignant diseases that require serial imaging during gestation, interventional procedures, or radiation therapy. 43 Accordingly, it is important to remember that the natural incidence of congenital anomalies in the general population generally varies between 0.5% and 5%, and exposure to a radiation dose of 10 mGy is associated with 0.5%, 0.4%, and 0.1% probabilities of malformations, microcephaly, and mental retardation, respectively. 41 In this line of investigation, studies have demonstrated that uterine exposure to even low radiation doses (20 mGy) increases the risk of cancer during childhood and the occurrence of leukemia, by a factor of 1.5 to 2.0, when compared to the natural incidence of these diseases. 43 The main radiological methods and the doses of radiation absorbed by the fetus, the patient, and the breasts (during lactation) are shown in Table 6. It is necessary to remember that no single radiological examination exposes the fetus to doses above 250 mGy, which could occur as a result of a combination of examinations or during the course of a treatment that is essential to the mother. When they do not directly involve the uterus or direct abdominal exposure, fluoroscopy, radiography, cardiac catheterization, and interventional radiology result in radiation doses that are not very significant to the fetus. Accordingly, it is necessary to consider strategies 44 that may reduce radiation, at times by around 30% to 65%. The following stand out: use of lead protectors on the abdomen, X-ray beam collimation in the area of interest, use of permanently calibrated and measured equipment, preference for digital radiography, and reduction of fluoroscopy time and number of images acquired. Furthermore, enlargements should be carried out using a lower number of images and exposures. In nuclear scintigraphy examinations, fetal ionizing radiation exposure comes from accumulated radioactivity in the maternal organism and from radiopharmaceutical transport and diffusion through the placenta. 45 Ventilation/perfusion (V/Q) scintigraphy is the most frequent scintigraphy imaging method with reduced maternal dose, compared to computed tomography pulmonary angiography (CTPA). CTPA, however, provides lower doses when the fetus is still small and farther from the field of view or the thorax. 862