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 Hyperkinetic Obstructive 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 Disease 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 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 HYPERTENSION AC. 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

(Heath. Edwards classification) 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 ↑

CONGENITAL HEART DISEASE PAH : Eisenmenger ASD 40 pts., FU – 4 years, PVR ↑ 7u ASD closed 26, Med. Rx -14 PVR 9-14 - No ↑ in PVR 7-9 - PVR ↓ No vasoreactivity check pre op PVR ↑ in all unopted. Steele etal Circ. 1987 : 76 : 1037 - 42

CONGENITAL HEART DISEASE PAH : Eisenmenger Pts : O2 ± No 124 Pts, 1 mt 47 yr. (m 28) 74 op or transplant PVR/ SVR – 0.33 or ↑ O2 → Rp/Rs ↓ 0.42 O2 + NO Rp/Rs ↓ 0.27 (indicates operable defect) Balzer etal Circ. 2002 : 106:1-76-81

Operability & Reversibility Not Synonymous Patients with severe intimal proliferation may not show decrease in PAP post-op PAH can progress after repair

Congenital Heart Disease PVR : mistakes in assessment Presence of A.V. valve regurg. Obligatory shunts Pulm. infection, acidosis, anemia, polycythemia, hypoxia

SUMMARY Knowledge of determinants of progression of PVOD is poor Remember confounding factors affecting PVR in assessing L→R shunts. Clinical auscultation- fading art.

SUMMARY Age of patient probably THE most important determinant * Pre tricuspid shunt except TAPVC- Longer waiting period * Post tricuspid shunt without cyanosis 6 months to 1 year * Post tricuspid shunt with cyanosis before 3 months

Message Timely surgical intervention is THE KEY for good immediate & long term results.

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