Presentation on theme: "Infective Endocarditis. Epidemiology and Prevention of Congenital Heart Defects Dr Alireza Ahmadi Assocciate Professor of Medical University of Isfahan."— Presentation transcript:
FROM EPIDEMIOLOGY TO PREVENTION: INCENTIVE, EVIDENCE, STRATEGIES, TOOLS Congenital anomalies ( birth defects) - 1 in 33 infants - 3.2 million birth defect-related disabilities every year 270 000 newborns die during the first 28 days of life every year from congenital anomalies
Congenital anomalies long-term disability, significant impacts on individuals, families, health-care systems and societies. The most common serious congenital disorders are heart defects, neural tube defects and Down syndrome. Congenital anomalies : - genetic, - infectious or - environmental origin.
EPIDEMIOLOGY OF OCCURRENCE AND OUTCOMES The occurrence of congenital heart defects can be evaluated using incidence and prevalence. Incidence number of new cases among an initially disease-free cohort of at-risk individuals within a specific time. Although a good measure of the "force" of disease, incidence is difficult to measure for congenital heart defects.
One difficulty is the disease-free at-risk cohort is formed, whose number cannot be estimated with any accuracy. Prevalence, occurrence of disease at a point in time in a defined population. Prevalence therefore can be estimated for fetuses at a certain gestational age, stillbirths, newborns, children, adults, or a combination of these.
Because it can be computed with easily available data, Prevalence at birth = Number of babies born with a heart defect.. Total number of babies (usually live births) in that period-is frequently used as a basic epidemiologic measure of occurrence. However, by not including early pregnancy losses, birth prevalence will underestimate the global impact of congenital heart defects.
Incidence Congenital heart disease in 0.5–0.8% of live births. In stillborns (3–4%), Spontaneous abortuses (10–25%), and premature infants (about 2% excluding [PDA]) This incidence does not include mitral valve prolapse, PDA of preterm infants, and bicuspid aortic valves (present in 1–2% of adults)
Prevalence 3 per 1,000 for clinically severe conditions, 6 per 1,000 including moderately serious conditions, 9 per 1,000 to 15 to 20 per 1,000 with further including smaller septal defects and milder valvar stenoses
1,200,000 affected babies are born worldwide every year (36,000 in the United States), of whom at least 400,000 babies are severely affected(12,000 in the United States) Prevalence among children and adults is less known. The American Heart Association estimates that approximately one million adults (or approximately 1 in 300 people) live in the United States with a congenital heart defect.
Outcomes: Mortality In North America CHD contribute to one third of infant deaths because of congenital anomalies, and, one tenth of all infant deaths About a quarter of fatalities due to congenital heart defects occur in the first month of life.
Advances in diagnostic procedures and surgical treatments increase in the survival rate of children with serious heart defects. Almost all are able to lead an active and productive life, but it is important to note that many patients continue to need special care throughout their life.
Occurrence: The Future Changing population structure could affect the occurrence of some heart defects. Shift toward older maternal age in some populations may lead to more pregnancies with heart defects associated with chromosomal trisomies. The rising frequency of risk factors for heart defects (e.g., untreated diabetes) in many countries is concerning. Monitoring and intervening to reduce risk factors should be a clinical and public health priority in pediatric cardiology
Causes & Risk Factors The exact causes of congenital heart disease are not known. However, genetic factors such as gene mutation can cause atrial septal defect (ASD), hypoplastic left heart syndrome (HLHS), rubella (German measles), viral infections such as flu, exposure to certain industrial solvents during the first three months of pregnancy cause congenital heart defects.
Most cases of CHD: Multifactorial genetic predisposition + === CHD environmental stimulus
Genetic contribution Evidence for a genetic contribution comes from several observations. First, specific types of CHDs are commonly seen in conjunction with specific chromosomal abnormalities. For example, atrioventricular septal defects are most commonly diagnosed in patients with trisomy 21, and patients with trisomy 21 are commonly diagnosed with atrioventricular septal defects.
Second, CHDs can occur in multiple members of a family, suggesting a genetic basis. - High heritability in certain of CHDs such as left- sided lesions. Third, epidemiologic studies demonstrate an increased recurrence risk for CHDs in families with one affected member.
CHROMOSOME ABNORMALITY SYNDROMES ASSOCIATED WITH CHD Trisomy 13,18,21 Turner syndrome Chromosome deletion or duplication Williams syndrome Deletion 7p13 Deletion 11q23 Jacobsen Syndrome Tetrasomy 22p Cat-eye syndrome Deletion 22q11 DiGeorge sequence Velocardiofacial syndrome Conotruncal anomaly face syndrome
chromosomal aberrations About 30 percent of children born with chromosomal aberrations, - such as Down’s Syndrome (mental retardation and physical birth defects) and Turner Syndrome (short stature and lack of sexual development), - suffer from congenital heart defects.
Importance of Identifying a Genetic Syndrome Early identification and treatment of associated non cardiac features. For example, 22q11 deletion associated non cardiac features : feeding disorders, palate anomalies, speech disturbances, hypocalcemia.
Appropriate family counseling regarding risks of recurrence. More accurate counseling regarding cardiac and non cardiac clinical outcome. Determining the patient genetic phenotype is essential to provide more accurate clinical care, estimation of prognosis, and assessment of risk.
Outcomes: Neurodevelopmental Disabilities Children without obvious extracardiac involvement may be at risk for adverse neurologic outcomes, possibly because of subtle brain anomalies, altered hemodynamics, cyanosis, stress, complications of surgery
Altered hemodynamics, particularly in ductal-dependent lesions, risk for seizures, intraventricular hemorrhage, and periventricular leukomalacia. neuropsychiatric conditions, including attention deficit and hyperactivity disorders, anxiety, depression, are diagnosed in older children and adults with congenital heart defects
Diabetes Maternal pregestational diabetes is an established teratogen, which affects not only the developing heart but also numerous extracardiac organs. Early developmental CHDs, i.e., laterality defects, looping, conotruncal defects, AVSD Odds Ratio 3 to 10, higher for some phenotypes Pregestational diabetes: 1%- 2% of women of childbearing age in United States; increasing in many countries
Febrile illness, influenza LVOTO, including: COA, tricuspid atresia, dTGA and other conotruncal malformations, VSD, possibly others. For febrile illness, COA; 1.5 and 3 (~2), Higher for tricuspid atresia. First trimester febrile illness reported in approximately 6% - 8% of pregnancies. Generally associated with respiratory or influenza like symptoms.
Maternal Phenylketonuria Tetralogy of Fallot, VSD, PDA, LVOTO Relative risk up to 6 Frequency of PKU is approximately 1 in 10,000 among whites Known teratogen. Relatively rare, but effects preventable with strict dietary compliance from before conception
Retinoic acid Conotruncal defects High absolute risk Isotretinoin, etretinate by mouth are teratogenic, topical tretinoin probably not.
Obesity Several heart defects, including conotruncal defects Relative risk between 1 and 3, but some studies are negative. Risks typically associated with BMI >29, but some studies show risks at BMI 25 to 29. Causality not clear. Association possibly owing in part to unrecognized diabetes.
Smoking Septal defects, others Relative risk between 1 and 3, but some studies are negative. In individual studies, risk present if both parents smoke and if father alone smokes (secondhand smoking) Causality not clear, but preventable. Smoking can cause other adverse pregnancy outcomes
Caffeine Caffeine crosses the placenta and can have cardiovascular effects. However, several large studies failed to identify increased risk for heart defects or other malformations
Alcohol Possibly several heart defects, including conotruncal defects Possible higher risk with high exposure, but not consistent finding Known teratogen, major effects on central nervous system, specific heart defects still being investigated.
Anticonvulsants Phenytoin, Hydantoin, and Valproic acid
Sulfa Antibiotics Some antibiotics such as dihydrofolate reductase inhibitors are folic acid antagonists. Specifically, trimethoprim-sulfonamide and sulfasalazine have been associated with a mild to moderate increase in risk for heart defects. In one study, the use of folic acid supplements decreased the excess risk associated with these compounds.
Lithium After initial reports suggesting that lithium was a strong risk factor for heart defects, and particularly for Ebstein's anomaly, more recent data have prompted a reassessment of such estimates. Recent estimates suggest that the risk associated with lithium is smaller than previously thought, although small to moderate increases in risk for Ebstein's anomaly cannot be excluded.
Prevention Methods Congenital heart defects cannot be prevented, but certain measures taken before and during pregnancy can help reduce the risk of having a baby with congenital heart defects. 1. Taking of multivitamin tablets containing 400 micrograms of folic acid can avoid serious birth defects of brain and spinal cord and may also help prevent congenital heart defects. 2. A pre-conception visit could help in testing for immunity from rubella and vaccination administered if the woman is not immune.
3. Women suffering from diabetes and phenylketonuria (PKU) must be adjusted with the necessary medication and eating habits to keep these conditions under control before and during pregnancy. 4. Pregnant women must avoid people suffering from flu or other viral infections. 5. Pregnant women must avoid exposure to organic solvents used in paints, varnishes and degreasing or cleaning agents, heavy metals, herbicides, pesticides.
GENETIC COUNSELING Consultation from a clinical geneticist should be sought for the cardiac patient with the following: Dysmorphic features, multiple congenital anomalies, neurocognitive deficits, or a family history of CHD, congenital anomalies, or neurocognitive deficits.
Since approximately 75% of CHDs currently have no identifiable cause or underlying condition, a formal genetic evaluation may appear to be unnecessary in many cases.
With the exception of syndromes known to be due to mutation of a single gene, most congenital heart disease is relegated to a multifactorial inheritance pattern, which should result in a low risk of recurrence.
The incidence of congenital heart disease in the normal population is ≈0.8%, 2–6% for a 2nd pregnancy after the birth of a child with congenital heart disease or if a parent is affected. This recurrence risk is highly dependent on the type of lesion in the 1st child. When two 1st-degree relatives have congenital heart disease, the risk for a subsequent child may reach 20–30%.
screening fetal echocardiogram For patients with a previous child or 1st-degree relative with CHD, For patients who are at higher risk of having a child with cardiac disease insulin-dependent diabetics, patients with exposure to teratogenic drugs during early pregnancy), any fetus in which a chromosomal abnormality is suspected or confirmed.