Truncus Arteriosus

Overview

Anatomy

• A single common arterial trunk gives rise to pulmonary trunk and aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy: 
  • Exact location from which pulmonary arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology arise varies (see classification).
• 1 valve associated with trunk: 
  • Semilunar valve known as truncal valve
  • Composed of variable Variable Variables represent information about something that can change. The design of the measurement scales, or of the methods for obtaining information, will determine the data gathered and the characteristics of that data. As a result, a variable can be qualitative or quantitative, and may be further classified into subgroups. Types of Variables (2–6) leaflets
  • Valve may be stenotic, regurgitant, or both.
• Associated cardiac anomalies include:
  • Ventricular septal defect Ventricular Septal Defect Tetralogy of Fallot (VSD): 
    • Always present in association to TA TA Thyrotoxicosis and Hyperthyroidism
    • Arterial trunk overrides septal defect.
  • Coronary artery anomaly: 
    • Coronary arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology originate from abnormal location.
    • No set pattern

Embryology

• Normal development:
  • Single truncal root gives origin to both great vessels ( aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy and common pulmonary trunk).
  • Trunco-conal septum forms within truncal root to separate it into pulmonary artery Pulmonary artery The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs. Lungs: Anatomy and ascending aorta Ascending aorta Mediastinum and Great Vessels: Anatomy.
  • Trunco-conal septum also fuses with endocardial cushions and interventricular septum Interventricular Septum Ventricular Septal Defect (VSD).
• Abnormal development:
  • Abnormal or absent growth of trunco-conal septum causes truncal root to remain 1 single vessel.
  • Failure of trunco-conal septum to fuse with intraventricular septum results in VSD formation and associated valvular abnormalities.

Classification

• Type 1 Type 1 Spinal Muscular Atrophy: Posterior left side of TA TA Thyrotoxicosis and Hyperthyroidism gives rise to pulmonary trunk, which then branches into left and right pulmonary arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology.
• Type 2 Type 2 Spinal Muscular Atrophy: No true pulmonary trunk; right and left pulmonary arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology arise separately directly from posterior aspect of TA TA Thyrotoxicosis and Hyperthyroidism.
• Type 3 Type 3 Spinal Muscular Atrophy: No true pulmonary trunk; right and left pulmonary arteries Arteries Arteries are tubular collections of cells that transport oxygenated blood and nutrients from the heart to the tissues of the body. The blood passes through the arteries in order of decreasing luminal diameter, starting in the largest artery (the aorta) and ending in the small arterioles. Arteries are classified into 3 types: large elastic arteries, medium muscular arteries, and small arteries and arterioles. Arteries: Histology arise separately directly from the lateral aspect of TA TA Thyrotoxicosis and Hyperthyroidism.

Epidemiology

• Incidence Incidence The number of new cases of a given disease during a given period in a specified population. It also is used for the rate at which new events occur in a defined population. It is differentiated from prevalence, which refers to all cases in the population at a given time. Measures of Disease Frequency: 5–15 per 100,000 live births
• 0.7% of all forms of congenital Congenital Chorioretinitis heart defects in live-born infants
• 4% of critical congenital Congenital Chorioretinitis heart disease

Etiology

• Not completely understood
• Postulated to be due to abnormal development of neural crest cells Neural crest cells Gastrulation and Neurulation at septal region
• Increase risk associated with:
  • Advanced maternal age
  • Maternal cigarette smoking Smoking Willful or deliberate act of inhaling and exhaling smoke from burning substances or agents held by hand. Interstitial Lung Diseases
  • DiGeorge syndrome DiGeorge syndrome DiGeorge syndrome (DGS) is a condition caused by a microdeletion at location q11.2 of chromosome 22 (thus also called 22q11.2 syndrome). There is a defective development of the third and fourth pharyngeal pouches, leading to thymic and parathyroid hypoplasia (causing T-cell immunodeficiency and hypocalcemia, respectively). DiGeorge Syndrome

Pathophysiology and Clinical Presentation

Pathophysiology

• Single arterial trunk results in: 
  • Mixing of oxygenated and deoxygenated blood
  • Blood pumped to both systemic and pulmonary circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment at same pressure
• Pulmonary overcirculation: 
  • Both right and left ventricle eject their cardiac output Cardiac output The volume of blood passing through the heart per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with stroke volume (volume per beat). Cardiac Mechanics into common trunk.
  • As pulmonary vascular resistance Resistance Physiologically, the opposition to flow of air caused by the forces of friction. As a part of pulmonary function testing, it is the ratio of driving pressure to the rate of air flow. Ventilation: Mechanics of Breathing (PVR) decreases postbirth:
    • Blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure into pulmonary artery Pulmonary artery The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs. Lungs: Anatomy > blood flow Blood flow Blood flow refers to the movement of a certain volume of blood through the vasculature over a given unit of time (e.g., mL per minute). Vascular Resistance, Flow, and Mean Arterial Pressure into aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy
    • Left-to-right shunt through VSD increases due to the pressure differential.
    • Pulmonary congestion and heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR) ensue.
• Eisenmenger physiology:
  • In untreated cases, prolonged pulmonary overcirculation leads to increased muscular tone of pulmonary vasculature.
  • Increased vascular tone leads to increased PVR.
  • Increased PVR leads to decreased pulmonary circulation Circulation The movement of the blood as it is pumped through the cardiovascular system. ABCDE Assessment and worsened cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination.
• Truncal valve insufficiency:
  • If valve is regurgitant:
    • During diastole Diastole Post-systolic relaxation of the heart, especially the heart ventricles. Cardiac Cycle, blood flows back into heart.
    • Results in reduced cardiac output Cardiac output The volume of blood passing through the heart per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with stroke volume (volume per beat). Cardiac Mechanics
    • Reduced cardiac output Cardiac output The volume of blood passing through the heart per unit of time. It is usually expressed as liters (volume) per minute so as not to be confused with stroke volume (volume per beat). Cardiac Mechanics causes coronary artery underperfusion → myocardial infarction Myocardial infarction MI is ischemia and death of an area of myocardial tissue due to insufficient blood flow and oxygenation, usually from thrombus formation on a ruptured atherosclerotic plaque in the epicardial arteries. Clinical presentation is most commonly with chest pain, but women and patients with diabetes may have atypical symptoms. Myocardial Infarction

Clinical presentation

Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship may be asymptomatic at birth but develop symptoms within 1st few days of life.

• Cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination:
  • Mild to moderate initially
  • Worsens once PVR falls
• Symptoms of respiratory distress and heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR):
  • Shortness of breath Shortness of breath Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea
  • Grunting Grunting Physical Examination of the Newborn
  • Lethargic
  • Poor feeding
  • Diaphoresis

Diagnosis

Physical exam

• Failed pulse oximetry screening Screening Preoperative Care test (persistently low saturation)
• Failure to thrive Failure to Thrive Failure to thrive (FTT), or faltering growth, describes suboptimal weight gain and growth in children. The majority of cases are due to inadequate caloric intake; however, genetic, infectious, and oncological etiologies are also common. Failure to Thrive
• Heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR):
  • Tachycardia Tachycardia Abnormally rapid heartbeat, usually with a heart rate above 100 beats per minute for adults. Tachycardia accompanied by disturbance in the cardiac depolarization (cardiac arrhythmia) is called tachyarrhythmia. Sepsis in Children
  • Hepatomegaly
  • Edema Edema Edema is a condition in which excess serous fluid accumulates in the body cavity or interstitial space of connective tissues. Edema is a symptom observed in several medical conditions. It can be categorized into 2 types, namely, peripheral (in the extremities) and internal (in an organ or body cavity). Edema
• Respiratory distress:
  • Tachypnea Tachypnea Increased respiratory rate. Pulmonary Examination
  • Dyspnea Dyspnea Dyspnea is the subjective sensation of breathing discomfort. Dyspnea is a normal manifestation of heavy physical or psychological exertion, but also may be caused by underlying conditions (both pulmonary and extrapulmonary). Dyspnea
  • Grunting Grunting Physical Examination of the Newborn
  • Nasal flaring
• Pulse:
  • Wide pulse pressure 
  • Bounding pulses
• Murmur:
  • Single, loud S2 S2 Heart Sounds
  • Ejection systolic murmur at apex or left sternal border
  • Truncal valve insufficiency → diastolic, high-pitched murmur at left sternal border

Imaging

• Echocardiogram Echocardiogram Transposition of the Great Vessels: 
  • Prenatal screening Screening Preoperative Care echo is usually sufficient.
  • Confirmatory in postnatal phase
  • Doppler Doppler Ultrasonography applying the doppler effect, with frequency-shifted ultrasound reflections produced by moving targets (usually red blood cells) in the bloodstream along the ultrasound axis in direct proportion to the velocity of movement of the targets, to determine both direction and velocity of blood flow. Ultrasound (Sonography) can be used to assess truncal valve insufficiency by measuring retrograde flow Retrograde flow Veins: Histology through valve.
• Chest X-ray X-ray Penetrating electromagnetic radiation emitted when the inner orbital electrons of an atom are excited and release radiant energy. X-ray wavelengths range from 1 pm to 10 nm. Hard x-rays are the higher energy, shorter wavelength x-rays. Soft x-rays or grenz rays are less energetic and longer in wavelength. The short wavelength end of the x-ray spectrum overlaps the gamma rays wavelength range. The distinction between gamma rays and x-rays is based on their radiation source. Pulmonary Function Tests:
  • Increased pulmonary vascular markings
  • Cardiomegaly Cardiomegaly Enlargement of the heart, usually indicated by a cardiothoracic ratio above 0. 50. Heart enlargement may involve the right, the left, or both heart ventricles or heart atria. Cardiomegaly is a nonspecific symptom seen in patients with chronic systolic heart failure (heart failure) or several forms of cardiomyopathies. Ebstein’s Anomaly
  • Absent thymic shadow (suggesting DiGeorge syndrome DiGeorge syndrome DiGeorge syndrome (DGS) is a condition caused by a microdeletion at location q11.2 of chromosome 22 (thus also called 22q11.2 syndrome). There is a defective development of the third and fourth pharyngeal pouches, leading to thymic and parathyroid hypoplasia (causing T-cell immunodeficiency and hypocalcemia, respectively). DiGeorge Syndrome)

Other tests

• Electrocardiogram Electrocardiogram An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG) showing:
  • Prominent P wave P wave Electrocardiogram (ECG)
  • Right and left ventricular hypertrophy Ventricular Hypertrophy Tetralogy of Fallot
• Arterial blood gases to determine degree of hypoxemia Hypoxemia Neonatal Respiratory Distress Syndrome and acidosis Acidosis A pathologic condition of acid accumulation or depletion of base in the body. The two main types are respiratory acidosis and metabolic acidosis, due to metabolic acid build up. Respiratory Acidosis in heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR)
• Serum calcium Calcium A basic element found in nearly all tissues. It is a member of the alkaline earth family of metals with the atomic symbol ca, atomic number 20, and atomic weight 40. Calcium is the most abundant mineral in the body and combines with phosphorus to form calcium phosphate in the bones and teeth. It is essential for the normal functioning of nerves and muscles and plays a role in blood coagulation (as factor IV) and in many enzymatic processes. Electrolytes levels ( DiGeorge syndrome DiGeorge syndrome DiGeorge syndrome (DGS) is a condition caused by a microdeletion at location q11.2 of chromosome 22 (thus also called 22q11.2 syndrome). There is a defective development of the third and fourth pharyngeal pouches, leading to thymic and parathyroid hypoplasia (causing T-cell immunodeficiency and hypocalcemia, respectively). DiGeorge Syndrome ( hypoparathyroidism Hypoparathyroidism Hypoparathyroidism is defined as reduced parathyroid hormone (PTH) levels due to poor function of the parathyroid glands. The cause of hypoparathyroidism is most commonly iatrogenic following neck surgery, but it can also be associated with genetic or autoimmune disorders as well as infiltrative diseases causing destruction of the normal parathyroid tissue. Hypoparathyroidism))

Management and Prognosis

Management

The initial management aims to medically stabilize the patient prior to surgical intervention.

• Medical:
  • Treat volume overload → diuretics Diuretics Agents that promote the excretion of urine through their effects on kidney function. Heart Failure and Angina Medication (e.g., furosemide Furosemide A benzoic-sulfonamide-furan. It is a diuretic with fast onset and short duration that is used for edema and chronic renal insufficiency. Loop Diuretics)
  • Improve myocardial contractility → inotropes Inotropes Hypoplastic Left Heart Syndrome (HLHS) (e.g., dopamine Dopamine One of the catecholamine neurotransmitters in the brain. It is derived from tyrosine and is the precursor to norepinephrine and epinephrine. Dopamine is a major transmitter in the extrapyramidal system of the brain, and important in regulating movement. Receptors and Neurotransmitters of the CNS)
  • Reduce afterload Afterload Afterload is the resistance in the aorta that prevents blood from leaving the heart. Afterload represents the pressure the LV needs to overcome to eject blood into the aorta. Cardiac Mechanics → ACE inhibitors
  • Treat acidosis Acidosis A pathologic condition of acid accumulation or depletion of base in the body. The two main types are respiratory acidosis and metabolic acidosis, due to metabolic acid build up. Respiratory Acidosis → bicarbonate Bicarbonate Inorganic salts that contain the -HCO3 radical. They are an important factor in determining the ph of the blood and the concentration of bicarbonate ions is regulated by the kidney. Levels in the blood are an index of the alkali reserve or buffering capacity. Electrolytes
• Surgical:
  • Definitive management
  • Performed within 1st few weeks of life
  • Single repair procedure that consists of:
    • Closure of VSD
    • Committing common arterial trunk to left ventricle
    • Reconstructing pulmonary artery Pulmonary artery The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs. Lungs: Anatomy and right ventricular outflow tract (RVOT)

Prognosis Prognosis A prediction of the probable outcome of a disease based on a individual’s condition and the usual course of the disease as seen in similar situations. Non-Hodgkin Lymphomas

• Untreated → 1-year survival < 15%, majority die < 5 weeks of life
• Treated → 1-year survival is 100%
• High cardiovascular morbidity Morbidity The proportion of patients with a particular disease during a given year per given unit of population. Measures of Health Status post-op, requiring regular Regular Insulin cardiology follow-up

Differential Diagnosis

• Tricuspid valve Tricuspid valve The valve consisting of three cusps situated between the right atrium and right ventricle of the heart. Heart: Anatomy atresia Atresia Hypoplastic Left Heart Syndrome (HLHS) (TVA): congenital Congenital Chorioretinitis heart disease characterized by lack of development of tricuspid valve Tricuspid valve The valve consisting of three cusps situated between the right atrium and right ventricle of the heart. Heart: Anatomy. Presents with cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination, labored breathing, hypoxic spells. Holosystolic murmur Holosystolic Murmur Tricuspid Valve Atresia (TVA), single S2 S2 Heart Sounds. Diagnosis made by echocardiogram Echocardiogram Transposition of the Great Vessels and ECG ECG An electrocardiogram (ECG) is a graphic representation of the electrical activity of the heart plotted against time. Adhesive electrodes are affixed to the skin surface allowing measurement of cardiac impulses from many angles. The ECG provides 3-dimensional information about the conduction system of the heart, the myocardium, and other cardiac structures. Electrocardiogram (ECG).
• Tetralogy of Fallot Tetralogy of Fallot Tetralogy of Fallot is the most common cyanotic congenital heart disease. The disease is the confluence of 4 pathologic cardiac features: overriding aorta, ventricular septal defect, right ventricular outflow obstruction, and right ventricular hypertrophy. Tetralogy of Fallot (TOF): congenital Congenital Chorioretinitis heart disease characterized by occurrence of 4 key cardinal features: overriding aorta Overriding Aorta Tetralogy of Fallot, VSD, RVOT obstruction, and right ventricular hypertrophy Right Ventricular Hypertrophy Tetralogy of Fallot. Patients Patients Individuals participating in the health care system for the purpose of receiving therapeutic, diagnostic, or preventive procedures. Clinician–Patient Relationship present with cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination and history of tet spells Tet Spells Tetralogy of Fallot ( cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination and fainting when crying). Diagnosis is confirmed by an echocardiogram Echocardiogram Transposition of the Great Vessels and the patient is surgically managed.
• Transposition of the great vessels Transposition of the Great Vessels Transposition of the great vessels (TGV) is a cyanotic congenital heart disease characterized by “switching” of the great arteries. There are 2 presentations: the dextro (D)- and levo (L)-looped forms. The L-looped form is rare and congenitally corrected, as the ventricles are also switched. Transposition of the Great Vessels (TGV): congenital Congenital Chorioretinitis heart defect characterized by switching of great vessels, so that aorta Aorta The main trunk of the systemic arteries. Mediastinum and Great Vessels: Anatomy originates from right ventricle and pulmonary artery Pulmonary artery The short wide vessel arising from the conus arteriosus of the right ventricle and conveying unaerated blood to the lungs. Lungs: Anatomy from left. Presents with cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination, tachypnea Tachypnea Increased respiratory rate. Pulmonary Examination, heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR), hypoxemia Hypoxemia Neonatal Respiratory Distress Syndrome unresponsive to supplemental oxygen Supplemental Oxygen Respiratory Failure.
• Total anomalous pulmonary venous return (TAPVR): rare congenital Congenital Chorioretinitis cardiopathy in which pulmonary veins Pulmonary veins The veins that return the oxygenated blood from the lungs to the left atrium of the heart. Lungs: Anatomy drain to sites other than left atrium. Presents with cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination from birth, heart failure Heart Failure A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (ventricular dysfunction), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as myocardial infarction. Total Anomalous Pulmonary Venous Return (TAPVR), respiratory distress. Characterized by wide-split S2 S2 Heart Sounds.
• Ebstein anomaly (EA): congenital Congenital Chorioretinitis heart defect in which there is downward displacement Displacement The process by which an emotional or behavioral response that is appropriate for one situation appears in another situation for which it is inappropriate. Defense Mechanisms of tricuspid valve Tricuspid valve The valve consisting of three cusps situated between the right atrium and right ventricle of the heart. Heart: Anatomy leaflets causing RVOT obstruction. Presents with cyanosis Cyanosis A bluish or purplish discoloration of the skin and mucous membranes due to an increase in the amount of deoxygenated hemoglobin in the blood or a structural defect in the hemoglobin molecule. Pulmonary Examination, arrhythmias, failure to thrive Failure to Thrive Failure to thrive (FTT), or faltering growth, describes suboptimal weight gain and growth in children. The majority of cases are due to inadequate caloric intake; however, genetic, infectious, and oncological etiologies are also common. Failure to Thrive. Diagnosed by echocardiogram Echocardiogram Transposition of the Great Vessels.