CONGENITAL HEART DISEASE AND ANESTHETIC

MANAGEMENT

By

Dr.A.Sattar

Dept;of Anesthesia,SIUT Karachi

Congenital anomalies of heart and Cardiovascular System –

• Incidence – 1% (10 per 1000 live births).

• 30% of the total incidence of all congenital diseases.

• More than 100 different CHD recognized.

• 90% CHD can be placed in 9 Categories.

• Remaining 10% are more unusual and complex congenital heart lesions.

COMMON CONGENITAL HEART DISEASES -

Disease Incidence

ACYANOTIC DEFFECTS -- Ventricular Septal Defect (VSD) - 30%- Atrial Septal Defect (ASD) - 10%- Patent Ductus Arteriosus (PDA) 10%- Pulmonary Stenosis - 10%- Aortic Stenosis - 7%- Coartation of the aorta - 5%- Atrioventricular Septal Defect - 3%CYANOTIC DEFECTS –- Tetralogy of Fallot - 10%- Transposition of the great vessels - 5%

ACYANOTIC CONGENITAL HEART DISEASE.

• Characterized by a left to right intracardiac shunt.

• Ultimate result of this shunt,regardless of its location is:

increased pulmonary blood flow

pulmonary hypertension

right ventricular hypertrophy

and eventually CCF

ACYANOTIC CONGENITAL HEART DISEASERESULTING IN A LEFT- TO- RIGHT

INTRACARDIAC SHUNT.

• Secundum Atrial Septal Defect (ASD).

• Primum Atrial Septal Defect (ASD) (Endocardial cushion Defect).

• Ventricular Septal Defect (VSD).

• Aorticopulmonary fenestration.

ATRIAL SEPTAL DEFECT (ASD)

• 1/3 of CHD detected in adults.• More in females.• Anatomically an ASD may be devided in:• Ostium secondum most common type located in the region of fossa ovalis,in the middle of interatrial septum. • Ostium primum less common endocardial cushion defect large opening,located in the lower interatrial septum.• Sinus Venosus located at upper interatrial septum.

ATRIAL SEPTAL DEFECT (ASD)

ATRIAL SEPTAL DEFECT (ASD)

• Physiologic consequences of ASD are the same regardless of anatomic location.

• The shunting of blood from one atrium to the other occurs.

• The direction and magnitude of the shunt are determined by the size of the defect and the relative comlpliance of ventricles.

• A small 0.5cm defect is associated with a small shunt and no haemodynamic problem.

• A 2cm defect result in shunting of blood from left to right and increased pulmonary blood flow.

ATRIAL SEPTAL DEFECT (ASD)

SIGNS AND SYMPTOMS• Initially no symptoms,no physical finding.

• May remain undetected for years.

• Small ASD with ratio of pulmonary to systemic flow of less than 1.5,no closure of ASD required.

• Large ASD,ratio more than 1.5,causes dyspnoea on exertion,supraventricular arrythmias,RHF,paradoxical embolism and recurrent pulmonary infections.

• A systolic ejection murmur is present in 2nd left intercostal space .

• ECG shows RAD,incomplete RBBB,AF,and SVT in adults.

• CXR shows prominent pulmonary arteries.

• Echocardiography with Doppler color flow is useful for detecting the location of ASD`s.

ATRIAL SEPTAL DEFECT (ASD)

ANESTHETIC MANAGEMENT

• In the absence of CCF,no significant alteration in intravenous or volatile anesthetic response.

• Avoid increase in SVR because it will increased magnitude of shunt.

• Decrease in SVR due to volatile anesthetics will decrease magnitude of shunt.

• IPPV will increase PVR that will also decrease the shunt.

• Avoid air entrance in circulation.

• Give prophylactic antibiotics against infective endocarditis if valvular abnormality is present.

• Transient SVT and AV conduction defect may occur in early post operative period after surgical repair of ASD.

VENTRICULAR SEPTAL DEFECT (VSD)

• The most common CHD in infants and children.

• Large number of VSDs close spontaneously before 2 years of age.

• Anatomically can be divided into: Membranous VSD – 70% Muscular VSD – 20% Others – 10%.

VENTRICULAR SEPTAL DEFECT (VSD)

VENTRICULAR SEPTAL DEFECT (VSD)

SIGNS AND SYMPTOMS

• Physiologic significance of VSD depends on size of the defect and the relative resistance in the pulmonary and systemic circulations.

• Small VSD – minimal functional disturbance.

• Large VSD – ventricular pressures equalize and magnitude of flow depends on SVR and PVR.

• Systolic murmur is heard at left lower sternal border.

• ECG shows RAD,RVH and LVH.

• CXR – initially normal.

• Echocardiography and Angiography are diagnostic.

VENTRICULAR SEPTAL DEFECT (VSD)

ANESTHETIC MANAGEMENT

• Antibiotic prophylaxis against infective endocarditis.

• Acute and persistent increase in SVR or decrease in PVR are undesirable as these will increase magnitude of shunt.

• The pharmacokinetics of inhaled and injected drugs are not significantly altered by VSD.

• High inspired concentration of volatile anesthetics may cause cardiac depression.

PATENT DUCTUS ARTERIOSUS (PDA)

• This is present when the ductus arteriosus fails to close spontaneously shortly after birth.

• Ductus arteriosus connects descending Aorta to left pulmonary artery,it closes 24 – 48 hours after birth but in preterms frequently fail to close.

• The result is a left-to-right shunt and increase pulmonary blood flow.

PATENT DUCTUS ARTERIOSUS (PDA)

PATENT DUCTUS ARTERIOSUS (PDA)

SIGNS AND SYMPTOMS• Most patients are asymptomatic.

• Only have modest left-to-right shunt.

• It left-to-right shunt is large it may cause LVH,pulmonary hypertension and RVH.

• If surgical closure is not done most patients remain asymptomatic until adolescence but may develop pulmonary hypertension and CCF.

• In severe pulmonary hypertension surgical and percutaneous closure is contraindicated.

• Often detected during routine physical examination with continuous systolic and diastolic murmur.

• ECG and CXR show LVH.

• Echocardiography with doppler studies confirms the dignosis.

PATENT DUCTUS ARTERIOSUS (PDA)

TREATMENT

• Surgical ligation is associated with low mortality and usually CPB is not required.

• In some cases medical closure of PDA with inhibition of prostaglandin synthesis with cox – 1 or cox – 2 appears to be effective as alternative to surgery.

PATENT DUCTUS ARTERIOSUS (PDA)

ANESTHETIC MANAGEMENT

• Antibiotic prophylaxis against infective endocarditis.

• Anticipate blood loss.

• Anesthesia with volatile anesthetic and IPPV is useful.

• Artrial BP monitoring is helpful.

• Ligation of PDA is often associated with hypertension in post operative period.

CYANOTIC CONGENITAL HEART

DISEASES • Characterized by a right-to-left intracardiac shunt with

associated decrease in pulmonary blood flow and the development of arterial hypoxemia.

• Chronic hypoxemia results in erythrocytosis and thromboembolism.

• Secondary erythrocytosis may cause coagulation defect.

• Risk of CVA and brain abscess.

• Without surgical treatment patient can not survive to adulthood.

CYANOTIC CONGENITAL HEART DISEASES RESULTING IN RIGHT-TO-

LEFT INTRACARDIAC SHUNT

• Tetralogy of fallot.

• Eisenmenger syndrome.

• Ebtein`s anomally (Tricuspid malformation).

• Tricuspid atresia.

• Foramen ovale.

TETRALOGY OF FALLOT• Most common cyanotic CHD.

• Characterized by a large single VSD,an aorta that overrides the right and left ventricles,obstruction to right ventricle out flow and right ventricular hypertrophy.

• TOF with ASD or other anomalies may occur (Pentalogy of fallot).

• Right-to-left entracardiac shunting occurs because of increased resistance to flow in the right ventricular out flow tract.

• Because resistance to flow across the right ventricular out flow tract is relatively fixed,changes in SVR (drug induced) may affect the magnitude of the shunt.

• Decrease in SVR,increase right-to-left intracardiac shunting and increase arterial hypoxemia.

• Increase in SVR decrease right-to-left intracardiac shunting with resultant increase in pulmonary blood flow.

TETRALOGY OF FALLOT

TETRALOGY OF FALLOT

DIAGNOSIS

• Echocardiography with color Doppler imaging and spectral Doppler measurement.

• Cardiac catheterization confirms diagnosis,anatomic and hemodynamic data.

• MRI.

TETRALOGY OF FALLOT

SIGNS AND SYMPTOMS

• Cyanosis: from birth or start in first year of life.

• CCF: rare because large VSD permits equalibration of intraventricular pressures and cardiac work load.

• Low oxygen saturation: even at 100% oxygen.

• Compensatory erythropoises.

• Squating is common.

TETRALOGY OF FALLOT

SIGNS AND SYMPTOMS

Hypercyanotic attacks• These are characterized by sudden spells of arterial hypoxemia associated with

worsening cyanosis,tachypnoea,loss of consceousness,seizures,CVA and even death.

• This is associated with crying and exercise due to sudden decrease in pulmonary blood flow due to spasm of infundibular cardiac muscle or decrease in SVR.

• Treatment is release of spasm by beta blockers like esmolol or proponolol but if the cause is decrease in SVR then give fluids and phenylephrine.

• Sympathomimetics with beta agonist activity should be avoided because they may cause spasm of infundibular cardiac muscle.

• Recurrent hypercyanotic attacks indicate need for surgical correction of TOF.

TETRALOGY OF FALLOT

SIGNS AND SYMPTOMS

CVA• Cause is cerebrovascular thrombosis or severe

hypoxemia.Thrombosis• Cause is polycythemia and dehydration.Cerebral abscess• Cause is arterial seeding into areas of prior cerebral

infarction.Infective endocarditis• associated with high mortality.

TETRALOGY OF FALLOT

ANESTHETIC MANAGEMENT

• Avoid increases in PVR or decrease in SVR because these will increase shunt magnitude that will decrease pulmonary blood flow and oxygen saturation.

• SVR is decreased by Volatile anesthetics,Histamine realese,Ganglionic blockade and Alfa adrenergic blockade.

• PVR is increase by High inflation pressures,Peep and acidosis.

TETRALOGY OF FALLOT

ANESTHETIC MANAGEMENT

Preoperative Preparation• Avoid dehydration,give i/v fluids.

• Avoid crying of patient,don’t give i/m injections.

• Continue beta blockers.

TETRALOGY OF FALLOTANESTHETIC MANAGEMENT

Induction of Anesthesia• Induce with Ketamine 1-2 mg/kg i/v.

• Decrease rate of muscle rexalant dose.

• Induction with volatile anesthetics is slow.

• Sevoflurane and Halothane can be used but with caution and careful monitoring of oxygenation.

• Hypercyanotic attacks may occur.

TETRALOGY OF FALLOT

ANESTHETIC MANAGEMENT

Maintenance of anesthesia• Can be achieved by Ketamine.

• Nitrous oxide but not more than 50% can be used but disadvantage is mild increase in PVR and decrease in FIO2.

• Opiods and benzodiazepine can be used in low dose to avoid SVR and BP.

• Muscle relaxation by pancuronium to maintain SVR and BP.

• IPPV – avoid airway pressure and peep.

• Maintain intravascular volume.

• Avoid infusion of air.

• Phenylephrine must be available to treat decrease in BP due to decrease in SVR.

SUMMARY

• Due to improvement in medical management the more number of CHD patients are encountered in anesthesia for non cardiac surgery.

• These CHD patients may be considered UNREPAIRED,CURED,CORRECTED or PALLIATED.

• Preoperative assessment include good history,physical examination,routine investigations,doppler echocardiography,review of old records,information from primary surgeon/physician and important post operative findings like arrhythmias,hypoxemia,pulmonary hypertension,existing shunts,paradoxical embolism and bacterial endocraditis.

SUMMARY

• Understand pathophysiology of defects.

• In left-to-right shunts avoid in SVR,infact decrease in SVR and increase in PVR are desireable.

BUT These are fatal in right-to-left shunts.

• So in right-to-left shunts avoid decrease in SVR and increase in PVR.