Key result
Right ventricular volume unloading via ASD closure increased left ventricular stroke work, but patients with ASD or repaired Tetralogy of Fallot maintained persistently higher contractility and arterial elastance than healthy controls.
Why the study?
It was unclear whether left ventricular hemodynamics differ between patients with right ventricular volume load (due to ASD or rToF) and healthy controls, and whether they change after intervention.
Does ASD closure or pulmonary valve replacement improve left ventricular hemodynamics and exercise capacity in patients with volume-loaded right ventricles?
Cohort (n=51)
No
Does ASD closure or pulmonary valve replacement improve left ventricular hemodynamics and exercise capacity in patients with volume-loaded right ventricles?
Absolute Event Rate: 1.1% vs 0.9%
p-value: p=0.02
Non-invasive PV loop analysis reveals that despite RV volume unloading, patients with ASD and rToF exhibit persistent vascular dysfunction (high arterial elastance), which may explain the lack of improvement in exercise capacity.
May indicate persistent LV effects after RV unloading in ASD/rToF; leaves open impact on outcomes and requires prospective validation.
Volume loading of the right ventricle (RV) in patients with atrial septal defect (ASD) and patients with repaired Tetralogy of Fallot (rToF) affects the pumping mechanics of the left ventricle (LV). Intervention of the lesion will relieve the RV volume load however quantifiable impact on exercise capacity, arrhytmias or death are limited. A possible explanation could be remaining effects on the function of the LV. The aim of this study was therefore to investigate if hemodynamics of the LV differs between patients with RV volume load due to ASD or rToF and healthy controls and if they change after intervention. Eighteen patients with ASD, 17 patients with rToF and 16 healthy controls underwent cardiac magnetic resonance imaging (CMR) and maximal exercise test with continuous gas analysis. Reexamination was performed 13 ± 2 months after closure of the ASD in 13 of the patients and 10 ± 4 months after pulmonary valve replacement (PVR) in 9 of the patients with rToF. Non-invasive PV-loops from CMR and brachial pressures were analyzed. Stroke work (SW) and potential energy (PE) increased after ASD closure but not in ToF patients after valve repair. Patients with ASD or rToF had higher contractility and arterial elastance than controls. No major effects were seen in LV energetics or in peak VO2 after ASD closure or PVR. Peak VO2 correlated positively with SW and PE in patients with ASD (r = 0.54, p < 0.05; r = 0.61, p < 0.01) and controls (r = 0.72, p < 0.01; r = 0.53, p < 0.05) to approximately the same degree as peak VO2 and end-diastolic volume (EDV) or end-systolic volume (ESV). In ToF patients there was no correlation between PV loop parameters and peak VO2 even if correlation was found between peak VO2 and EDV or ESV. In conclusion, the LV seems to adapt its pumping according to anatomic circumstances without losing efficiency, however there are indications of persistent vascular dysfunction, expressed as high arterial elastance, which might have impact on exercise performance and prognosis. Future studies might elucidate if the duration of RV volume load and decreased LV filling have any impact on the ability of the vascular function to normalize after ASD closure or PVR.
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Sjöberg et al. (2023) conducted a cohort in Volume-loaded right ventricle due to atrial septal defect (ASD) or repaired Tetralogy of Fallot (rToF) (n=51). Right ventricular volume unloading (ASD closure or pulmonary valve replacement) vs. Pre-intervention baseline and healthy controls was evaluated on Left ventricular stroke work (SW) in Joules after ASD closure (p=0.02). Right ventricular volume unloading via ASD closure increased left ventricular stroke work, but patients with ASD or repaired Tetralogy of Fallot maintained persistently higher contractility and arterial elastance than healthy controls.
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