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Assessment for operability of CHD with PAH R. Tandon. CONGENITAL HEART DISEASE. 8 to 10 / 1000 live births Uncorrected – 30 % PAH PPH of new born Idiop. Ped. PAH. L > R Shunt with PAH. Acyanotic CHD - PDA - VSD - AVSD - AP Window - ASD Cyanotic CHD with ↑ Qp
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Assessment for operability of CHD with PAH R. Tandon
CONGENITAL HEART DISEASE • 8 to 10 / 1000 live births • Uncorrected – 30 % PAH • PPH of new born • Idiop. Ped. PAH
L > R Shunt with PAH • Acyanotic CHD - PDA - VSD - AVSD - AP Window - ASD • Cyanotic CHD with ↑ Qp (Transposition physiology)
Cyanotic CHD with ↑ Qp(Transposition physiology) • Complete TGA • DORV, ↑Qp • TA, ↑ Qp • PTA • SV, ↑ Qp • TAPVC • Miscellaneous malp. without obstr. to pulm. blood flow
Congenital Heart Disease Pulm. Circ: PAH • CHD -↑ QP, ↑ Pr, ↑ O2 sat, ?? • Hypoperf, 2° to under development • Blood Viscosity • Thrombo–embolic obstr. • Aorto–pulm. Collat.
Congenital Heart Disease Pulm. hypertension : PA Pr. = Pulm flow x PVR Hyperkinetic = flow Obstructive = PVR
Principles Low resistance pulmonary circuit 1) Qp 2) Vol. overload High resistance pulmonary circuit 1) Curtailment of Qp 2) Loss of volume loading
CONGENITAL HEART DISEASE PAH : • Hyperkinetic - PVR normal • Obstructive - PVR ↑ • Due to PVH - PVR normal, ± ↑
CONGENITAL HEART DISEASE Pulmonary Hypertension : dx • PA (m) ↑ 25 • PAW/LAm/LVedp 15 mm or ↓ • PVR ↑ 3u (Incorrect)
Factors determining development of PVOD • Type of intracardiac defect • Age • PA Pressure • PV Pressure • PBF, PAO2 • Hypoxia • Acidosis • Unexplained - ? Genetic suscept. ? Endoth. dysf.
Congenital Heart Disease Pulmonary hypertension : Operability • Age • Lesion • Physical findings • Systemic O2 saturation • Investigations • Non-invasive • Invasive
Congenital Heart Disease PVOD : Age • Unknown 3 m • Rare 6 m • Uncommon 1 yr Except in TGA physiology
Congenital Heart Disease in PVR : • Improving symptoms • in CCF • Improved exercise capacity • Cyanosis : Absent, intermittent, persistent.
Congenital Heart Disease PVOD : Lesion • Very early - 3 m TGA Physio., AP window, Comp. AVC defects • Large PDA earlier than VSD (↓ 1 yr). • ASD – rare
Pulmonary hypertension HyperkineticObstructive Heart size large normal (except in ASD) Parasternal hyperkinetic forcible or heaving in ASD impulse mild in VSD & PDA Click of PAH absent present Second sound ASD‑wide & fixed ASD - wide and fixed (P2 accent‑ VSD‑wide & variable VSD - single uated in both) PDA‑paradoxically PDA - normal split Shunt murmur loud short or absent Flow murmur present absent
Congenital Heart Disease PVOD : Syst. O2 saturation • L R shunt - 93% - PVR 95%, PVR not excluded • TGA physiol. - 85% high flow and low PVR
Congenital Heart Disease PVOD • ECG : Increasing RVH - Not helpful • X-ray : * Heart size * Pulm. Vasculature Characteristics changes appear too late.
Congenital Heart Disease Pulm. hypertension : Echo assessment : PA syst. pr - Good PA diast. pr - Reasonable PA mean pr - Poor For assessment of PVR – cath is gold standard and essential.
Congenital Heart DiseaseInvasive evaluation Invasive evaluation • Hemodynamic study. • Pulmonary wedge angiography. • Biopsy – Pulmonary histology. • Pulmonary vascular compliance. (MRI & intravascular ultrasound)
CONGENITAL HEART DISEASE PAH Cath study: • Pressures – RA,RV,PA, PAW, LA/LVED,SA • Saturations – SVc, RA,RV,PA,SA • VO2, CI, SVR, PVR • HR • pO2, pH • Effect of intervention.
Cardiac Catheterisation • Measurement of PAP • Measurement of PVR • Vascular Reactivity PVR = PAm - LAm Qp If PVR & PAH - pO2 and pH essential.
Congenital Heart Disease Flow: (Poiseuille) ΔP. π r4 Q= 8ŋL
Congenital Heart Disease PAH: PA (m) – LA (m) . 8Lη PVR= Qp π r4 Assumes constant steady flow
Congenital Heart Disease Assessment for reactivity : • Oxygen • Isuprel infusion • Nifedipine • Prostaglandin • SNP, NO. PVR ↓ 6 units – operable.
Congenital Heart Disease Flows: VO2 Qp= PVO2 –PAO2 VO2 Qs= PVO2 (SA)–MVO2 Qp= Qs
Congenital Heart Disease Pulmonary hypertension : VO2 • Must be measured • Assumed value cannot be used For PVR calculation to determine operability.
Congenital Heart Disease Flows: Qp/Qs ratio SAO2 – MVO2 Qp/Qs= PVO2 – PAO2 Eliminates need to measure VO2
Congenital Heart Disease Flows: Qp/Qs ratio SAO2 – MVO2 PV (SA)O2 – PAO2 Echo: SVLV SV X HR = Qs Qp from Qp/Qs
CONGENITAL HEART DISEASE PAH – PVR • Fixed : PVOD • Variable: Vasoconstr - 20% pts.
Congenital Heart Disease PAH: • Operable – PVR ↓ 6u Rest or ac. • Inoperable – PVR ↑ 8u testing. Grey zone 7u ±1.
CONGENITAL HEART DISEASE PAH Vasodilat testing : Identifies - Prognosis - Responders (utility of CCB)
PULMONARY HYPERTENSIONAC. VASODILAT TESTING All PATIENTS • Contraindications : RV failure Unstable haemodynamics • + Ve resp. : PA (m)→↓ by 10 mms absolute level ↓ 40 mms (no ↓ in Co.) 20% ↓ in PApr & PVR
Congenital Heart Disease Pulm. hypertension : Reversibility • Qp on the basis of assumed VO2 - not reliable • 100% : O2–VO2 not known, hence all calculation will be incorrect. • Dissolved O2 - (modifies calculations)
Congenital Heart Disease PVOD : O2 study • PA saturation increases abnormally giving increased calculated QP and low PVR. • Fall in PA pressure more reliable. Fall in PA diast. pr may result in lower mean pressure.
Problems with vasodilators Oxygen - fick’s principle NA - Failure to respond in patients with reactive airway disease Tolazoline,PG, Ca Block - Fall in SVR - Arterial hypotension - VP mismatch Isoprenaline - Very high heart rates
CONGENITAL HEART DISEASE PAH : Nitric oxide: • Vasodilator • Inhibits - Platelet activation - SMC proliferation • ↓ levels in PAH • NO → cGMP (inactivated by PDE-5, large amounts in lungs)
NO Advantages - No ↑ in syst. sat. - No systemic hypotension - No arterial hypoxemia Disadvantages - Methaemoglobinemia - Pulmonary edema - Lung injury
NO as Pulmonary vasodilator - Results • NO at 40 ppm more effective than 5 ppm • 3/15 (20 %) pt with PVR > 8 u fall in PVR < 6 after NO • Response same in those with Down Syndrome Yasuda T et al,Paediatric Cardiol,2000
NO vs NO + Oxygen combination • Number of responders with combination significantly > than when NO/Oxygen used alone. • Combination of NO + 02 provides add’nal pulmonary vasodilatation & can rapidly identify patients with pulmonary vasoreactivity. • Good postoperative results Lock et al , JACC 2000
NO + Oxygen combination : PVR 10 u • O2 alone PVR 8 u • O2 + NO PVR 6 u Does not guarantee operability Wilkinson heart 2001 : 85:113
Lung biopsy • Open lung specimen is taken • General anaesthesia Biopsy those with borderline haemodynamics (Heath. Edwards classification)
CONGENITAL HEART DISEASE PAH Creating ASD - RVF not relieved • R → L shunt - ↓ RA pr. • QP ↓, Syst. O2 sat. ↓ CO more stable – syncope relieved. Change in life span - ?
Congenital Heart Disease PVOD : Defect occlusion PDA & some VSDs Significant fall in PA pressure is helpful in decision making.
CONGENITAL HEART DISEASE PAH Treatment • Prostanoids - Epoprostenol IV • E.R.A. - Bosentan PO • PDE-5-I - Sildenafil PO • CCB - Diltiazem, Amlodip. PO
CONGENITAL HEART DISEASE PAH: Breathe – 5 : ASD & VSD Bosentan Vs Placebo – 54 pts., class III, 16 weeks • Syst. O2 Sat. maintained. • PVR, PAm ↓ • Ex. Cap.↑, funct. class ↑ • Time to deterioration ↓ • Placebo – PVR worsened (?)
CONGENITAL HEART DISEASE PAH : Bosentan : Long FU (12 m – 29 m) • PVR/ SVR ratio ↓ (N- 0.15 to ↓ 0.3) • Qp & Qs ↑, R →L shunt ↓ • PAp & SAp ↓ (NS) • RV after load ↓ more than LV Initial improvement returns to baseline in 2 years.
CONGENITAL HEART DISEASE PAH : Bosentan • Hepatotoxicity • Potentially teratogenic • Testicular atrophy & infertility • Hormonal birth control - ↓ effectiveness.
CONGENITAL HEART DISEASE PAH : Sildenafil • PAp (m) ↓ 3-5 mms • Ex. capacity ↑ • Side effects – minor • Functional class ↑