Juan M Bolivar

Introduction Most common cyanotic congenital anomaly Incidence 3.26 per 10,000 live births (about 1300 new

cases per year in the United States)

1888, Etienne-Louis Arthur Fallot described three

cyanotic patients with four similar anatomic features: Stenosis of the pulmonary artery Intraventricular communication Deviation of the origin of the aorta to the right Concentric right ventricular hypertrophy

Embriology: there is anterior and cephalad deviation

of the infundibular septum. Malaligned ventricular septal defect (VSD). Primary problem in tetralogy of Fallot is underdevelopment of the pulmonary infundibulum Right ventricular hypertrophy: systemic right ventricular systolic pressure.

This constellation Tetralogy of Fallot 7-10% of congenital heart lesions Almost equal in males and females (slight male >)

Natural History Approximately 25% of untreated patients with TOF

and RVOT obstruction die within the first year of life, 40% by 4 years, 70% by 10 years, and 95% by 40 years

TOF1. Pulmonary Stenosis2. Right Ventricular Hypertrophy

3. Ventricular Septal Defect4. Overriding of the Aorta

ASSOCIATIONS 15% have extra-cardiac anomolies Includes chromosomal abn like Downs, Di George and

velocardiofacial syndromes (del chr 22), Alagille syndrome (mutations in Jagged1) Other genetic, non-syndromic abn have been documented in patients with TOF, including mutations in transcription factor NKX2.5 in approximately 4 % In 70% of TOF patients genetic etiology is unidentified TOF is frequently associated with

Fetal hydantoin syndrome Fetal carbamazepine syndrome Fetal alcohol syndrome Maternal PKU birth defects

Variants Simple tetralogy of Fallot with pulmonary stenosis

(61%) Tetralogy of Fallot with pulmonary atresia (33%) Tetralogy of Fallot with absent (or dysplastic)

pulmonary valve (3%) Tetralogy of Fallot with common atrioventricular canal

(3%)

Blue or Tet spells Hyperneic and Cyanosis Gasping Syncope

restless

respirations

TET SPELL MANAGEMENT Calm the patient, do not stimulate Increase venous return If IV, bolus of fluids

Sedation (Morphine) Intubation/paralysis Na bicarbonate Phenyephrine

RX AP Boot or Wooden Shoe Hypertrophied RV causes a right apical shadow Aorta is large and it may arch to the right.

EKG

Right axis deviation Right or combined ventricular hypertrophy Right atrial hypertrophy (prominent p waves in V1) Partial or complete right bundle branch block Most commonly seen after surgical repair

TOF Treatments Infant: Maintain PDA with IV PgE1 (0.05-0.2

mg/Kg/min) Propanolol PO fq of spells (1mg/Kg/dose) Maintain good hydration and temperature.

ANGIOGRAMS

LV angio large VSD (*), Aorta is over-riding the interVentricular septum (IVS)

RV angio subvalvar obstruction is so severe that with systole there is no contrast in RVOT. Small ridge of supravalvar narrowing

SURGICAL MANAGEMENT Palliation BTS in 1945. now been modified using the

Gortex tube to create the connection b/w Subclavian Artery and Pulmonary Artery. Still used in infants not good candidates for intracardiac repair

premature, hypoplastic pulm arteries, coronary art anatomy.

Intracardiac repair by Lillehi in 1954. Patch closure of

VSD and enlargement of RVOT.

Latter repair of pulm valve, resecting infundibular and sub-

infundibular muscle bundles, occ transannular patch. Disadv of transannular patch makes Pulm Valve incompetent. Alternately, insertion of a valved conduit from RV to distal MPA can be performed.

Timing surgery done electively in first yr of life, first 3

months if necessary. Also in pink variants nowadays.

TOF Treatments Blalock-Taussig Shunt Shunt from R Subclavian Artery R Pulmonary Artery Increase Pulmonary flow Result in Higher O2 Sat.

Goals of Corrective Surgery Removing obstructing muscle Closure of VSD Valvectomy of Pulmonic valve Transannular patch placed across the pulmonary valve

ring. Digoxin

Types of RVOT surgeies TAP Non TAP Double patch repair

TAP with Pulm Valve preservation

SURGICAL MANAGEMENT

POP Care Monitoring Art line ECG CVP

Pacing wires (Not at MCH) LA line (Not at MCH) PA line (Not at MCH)

POP Care Evaluate for residual VSD, RV dysfunction and RVOT

obstruction Evaluate for arrhythmia ( JET, Ventricular ectopy, heart block) Always keep good preload

RV dysfunction High CVP Low CO, high lactate Cyanosis

Echo

Junctional Ectopic Tachycardia Tachycardia No P waves AV disociation

Cannon waves Low CO, high lactates

JET

JET management Correct hypovolemia, anemia and electrlyte imbalance Hypothermia or at least correction of fever. Cooling

blankets, ice bags (sedation and paralysis required) Reduction in cathecolamines Atrial pacing Meds: Digoxin, Amiodarone

POP Medical Management Fast track extubation Sedation and pain management (Dexmedetomidine) Lusotropy and afterload reduction (Milrinone)

Calcium drip Keep good preload

LONG TERM OUTCOME Generally good in TOF patients Risk of complications such as sudden cardiac death and

heart failure. Myocardial fibrosis has adverse effect on long-term outcomes. In a study describing 36 yr outcomes of 490 survivors mortality increased 25 yrs after sx from 0.24 to 0.94/yr Euro Heart Survey in adults with TOF 1.3% mortality at 5yrs. Since 1985, major changes in mgmt of TOF such as repair in infancy and improved surgical outcome are expected to improve long-term outcomes.

Long Term Problems Free PI RV dysfunction RV Arrhythmias

Long Term Solutions RV to PA valved homograft or valved contegra Trans catheter Edwards or Melody valve

Trans catheter pulmonary valve The Melody valve is made

from a cows jugular vein valve that is sewn into a small metal stent

Edwards SAPIEN Transcatheter Heart ValveThe Edwards SAPIEN Transcatheter Heart Valve (THV) is a heart valve that is made of cow tissue attached to a stainless steel mesh frame with a polyester wrap.

Pulmonary Atresia with VSD and 'MAPCAs' This defect is a form of Tetralogy of Fallot in which

there is complete obstruction of the Pulmonary Artery resulting in total diversion of blood from the right ventricle into the aorta. Survival depends on the presence of a number of naturally occurring connecting blood vessels between the Aorta and the Pulmonary Arteries in the lungs, which are called 'Collaterals' - or sometimes MAPCAs (Major Aorto-Pulmonary Collateral Arteries).

Surgical Options

Surgery Rv to PA homogrft or conduit Unifocalization VSD closure

Prognosis High Mortality with or without surgery Multiple cardiac catheterizations Staged Surgeries

Airway compromise Increase PVR risk of PHT