33 PULMONARY HYPERTENSION AC. VASODILAT TESTING All PATIENTS Contraindications : RV failureUnstable haemodynamics+ Ve resp. : PA (m)→ ↓ by 10 mmsabsolute level ↓ 40 mms (no ↓ in Co.)20% ↓ in PApr & PVR
34 Congenital Heart Disease Pulm. hypertension : ReversibilityQp on the basis of assumed VO2 - not reliable100% : O2–VO2 not known, hence all calculation will be incorrect.Dissolved O2 - (modifies calculations)
35 Congenital Heart Disease PVOD : O2 studyPA 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.
36 Problems with vasodilators Oxygen fick’s principle NA- Failure to respond in patients with reactive airway diseaseTolazoline,PG, Ca Block- Fall in SVR- Arterial hypotension- VP mismatchIsoprenaline - Very high heart rates
37 CONGENITAL HEART DISEASE PAH : Nitric oxide:VasodilatorInhibits - Platelet activation- SMC proliferation↓ levels in PAHNO → cGMP(inactivated by PDE-5, large amounts in lungs)
38 NO Advantages - No ↑ in syst. sat. - No systemic hypotension - No arterial hypoxemiaDisadvantages- Methaemoglobinemia- Pulmonary edema- Lung injury
39 NO as Pulmonary vasodilator - Results NO at 40 ppm more effective than 5 ppm3/15 (20 %) pt with PVR > 8 ufall in PVR < 6 after NOResponse same in those with Down SyndromeYasuda T et al,Paediatric Cardiol,2000
40 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 resultsLock et al , JACC 2000
41 NO + Oxygen combination : PVR 10 u O2 alone PVR 8 uO2 + NO PVR 6 uDoes not guarantee operabilityWilkinson heart 2001 : 85:113
42 (Heath. Edwards classification) Lung biopsyOpen lung specimen is takenGeneral anaesthesiaBiopsy those with borderline haemodynamics(Heath. Edwards classification)
43 CONGENITAL HEART DISEASE PAHCreating ASD - RVF not relievedR → L shunt - ↓ RA pr.QP ↓, Syst. O2 sat. ↓CO more stable – syncope relieved.Change in life span - ?
44 Congenital Heart Disease PVOD : Defect occlusionPDA & some VSDsSignificant fall in PA pressure is helpful in decision making.
47 CONGENITAL HEART DISEASE PAH: Breathe – 5 : ASD & VSDBosentan Vs Placebo – 54 pts., class III, 16 weeksSyst. O2 Sat. maintained.PVR, PAm ↓Ex. Cap.↑, funct. class ↑Time to deterioration ↓Placebo – PVR worsened (?)
48 CONGENITAL HEART DISEASE PAH : Bosentan : Long FU (12 m – 29 m)PVR/ SVR ratio ↓ (N to ↓ 0.3)Qp & Qs ↑, R →L shunt ↓PAp & SAp ↓ (NS)RV after load ↓ more than LVInitial improvement returns to baseline in 2 years.
53 Operability & Reversibility Not SynonymousPatients with severe intimal proliferation may not show decrease in PAP post-opPAH can progress after repair
54 Congenital Heart Disease PVR : mistakes in assessmentPresence of A.V. valve regurg.Obligatory shuntsPulm. infection, acidosis, anemia, polycythemia, hypoxia
55 SUMMARY Knowledge of determinants of progression of PVOD is poor Remember confounding factors affecting PVR in assessing L→R shunts.Clinical auscultation- fading art.
56 SUMMARY Age of patient probably THE most important determinant * Pre tricuspid shunt except TAPVC- Longer waiting period* Post tricuspid shunt without cyanosis6 months to 1 year* Post tricuspid shunt with cyanosisbefore 3 months
57 Message Timely surgical intervention is THE KEY for good immediate & long termresults.