Background: Complete assessment of right heart function includes assessment of the right atrial and ventricular function. Right ventricular systolic function can be assessed by 2 D echocardiogram using tricuspid annular plane systolic excursion (TAPSE) and right ventricular fractional area change (RVFAC). Right ventricular diastolic function is difficult to assess especially in pediatric patients. TAPSE has an upstropke and a downstroke. The displacement in the upstroke is used to measure the RV systolic function. The downstroke could be utilised for assessing the right ventricular diastolic function. Right ventricular diastolic function and its importance in the management of patients with pulmonary arterial hypertension is currently not established. In this study we aimed to quantify the right ventricular diastolic function using TAPSE and establish its prognostic significance.
Materials and methods: We studied patients of PAH without shunt lesions referred to our centre. All patients underwent a detailed clinical examination, echocardiogram, Cardiac catheterization, NT pro-BNP and six minute walk test whenever feasible. All patients were regularly followed up. Clinical deterioration was defined as death, creation of POTTS shunt or addition of prostacyclin analogues. Total right heart function was measured using TAPSE. Down-stroke in TAPSE was broken down into two components; excursion occurring from the peak of the TAPSE to the beginning of p wave on ECG (TAPSERv) and from the beginning of the p wave to the trough of TAPSE (TAPSERA). The percentage of TAPSERA (%TAPSERA) in relation to the entire TAPSE was calculated.
Results: We studied 48 children (17F), median age 3 yrs (range 0.3-17), median BSA 0.56 m2 (0.2-1.8). Echocardiogram was done on all patients at the time of initial presentation to the PAH clinic. 8 Patients underwent Potts shunt, 1 was started on iloprost and there were 6 deaths. Median event free survival was 2yrs (0.2–3.4). One and 3 yr event free survival were 86 and 58% respectively. %TAPSE RA was significantly higher in patients with clinical deterioration (72+6 vs 34 +8), p= <0.001 and correlated with higher NT-proBNP and lower 6 mins walk distance. %TAPSE RA of >60% and RVFAC of <25% were independently associated with event free survival ay 3 years (p= 0.02 and p = 0.03).
Conclusion: In children with PAH, RV systolic and diastolic dysfunction are associated with poor outcomes. Diastolic dysfunction precedes systolic dysfunction in patients with PAH. %TAPSE RA can be used as a marker of reliance on atrial contribution in maintaining cardiac output. Loss of this contribution can lead to clinical deterioration. Regular monitoring of %TAPSE RA can identify the subset of patients who are prone to clinical deterioration and thus need closer follow up and escalation of therapy