Comparison of stroke work between repaired tetralogy of Fallot and normal right ventricular physiologies

Abstract

Adult patients who underwent tetralogy of Fallot repair surgery (rTOF) confront life-threatening ailments due to right ventricular (RV) myocardial dysfunction. Pulmonary valve replacement (PVR) needs to be performed to restore the deteriorating RV function. Determination of correct timing to perform PVR in an rTOF patient remains subjective, due to the unavailability of quantifiable clinical diagnostic parameters. The objective of this study is to evaluate the possibility of using RV body surface area (BSA)-indexed stroke work (SW(I)) to quantify RV inefficiency in TOF patients. We hypothesized that RV SW(I) required to push blood to the lungs in rTOF patients is significantly higher than that of normal subjects. Seven patients with rTOF pathophysiology and eight controls with normal RV physiology were registered for this study. Right ventricular volume and pressure were measured using cardiac magnetic resonance imaging and catheterization, respectively. Statistical analysis was performed to quantify the difference in SW(I) between the RV of the rTOF and control groups. Right ventricular SW(I) in rTOF patients (0.176 ± 0.055 J/m(2)) was significantly higher by 93.4% (P = 0.0026) than that of controls (0.091 ± 0.030 J/m(2)). Further, rTOF patients were found to have significantly higher (P< 0.05) BSA normalized RV end-systolic volume, end-systolic pressure, and regurgitation fraction than control subjects. Ejection fraction and peak ejection rate of rTOF patients were significantly lower (P < 0.05) than those of controls. Patients with rTOF pathophysiology had significantly higher RV SW(I) compared with subjects with normal RV physiology. Therefore, RV SW(I) may be useful to quantify RV inefficiency in rTOF patients along with currently used clinical end points such as RV volume, pressure, regurgitation fraction, and ejection fraction.

Prognostic value of right ventricular ejection/filling parameters in IPAH using cardiac magnetic resonance: A prospective pilot study

“…In the study by Lee et al ., RV PER was significantly lower in adult patients who underwent tetralogy of Fallot repair surgery and had deteriorating RV function. Theoretically, PER happens at the rapid ejection period and is a parameter of RV early systole.…”

Energy Transfer Ratio as a Metric of Right Ventricular Efficiency in Repaired Congenital Heart Disease

“…The PA regurgitant flow and PA obstruction directly affect the RV performance and efficiency as confirmed in our previous work. 26 It showed that a patient with repaired TOF physiology, including PA regurgitation and PA obstruction, had a significantly higher RV SW I compared with a subject with normal RV physiology. Thus, both RV pressure and volume overloading resulting from mainly PA regurgitation and PA obstruction need to be taken into account for long-term follow-up for patients after repair.…”

“…The RV SW was calculated by computing the area enclosed by the pressure-volume (P-V) loop by applying Gauss theorem. 24,26 Therefore, RV SW is given by:…”

“…The present research is a natural extension of our recently published study. 26 We evaluated e MPA between the RV and MPA for patients with RV-PA pathophysiology from TOF, TGA, pulmonic stenosis, and Ross procedure and control subjects with normal RV-PA physiology. The mean e MPA was compared between the two groups to test the hypothesis that e MPA for patients with RV pathophysiology would be significantly lower than that of controls with normal RV-PA physiology.…”

Non-invasive evaluation of energy loss in the pulmonary arteries using 4D phase contrast MR measurement: a proof of concept

“…The right-hand side of Eq. 5b, 5c, and 5d, i.e., the rate of the pressure-flow and kinetic energy terms at the PAs [9], RPA, LPA and MPA, respectively, can be substituted into Eq. 5a while maintaining flow balance at the PAs ( Q MPA  =  Q RPA  +  Q LPA ).…”