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AbstractBackgroundThe arterial switch operation for transposition of the great arteries was initially believed to be an anatomical correction. Recent evidence shows reduced exercise capacity and left ventricular function in varying degrees in the long term after an arterial switch operation.ObjectiveTo perform a meta-analysis on long-term exercise capacity and left ventricular ejection fraction after an arterial switch operation.MethodsA literature search was performed to cover all studies on patients who had undergone a minimum of 6 years of follow-up that reported either left ventricular ejection fraction, peak oxygen uptake, peak workload, and/or peak heart rate. A meta-analysis was performed if more than three studies reported the outcome of interest.ResultsA total of 21 studies reported on the outcomes of interest. Oxygen uptake was consistently lower in patients who had undergone an arterial switch operation compared with healthy controls, with a pooled average peak oxygen uptake of 87.5±2.9% of predicted. The peak heart rate was also lower compared with that of controls, at 92±2% of predicted. Peak workload was significantly reduced in two studies. Pooled left ventricular ejection fraction was normal at 60.7±7.2%.ConclusionExercise capacity is reduced and left ventricular ejection fraction is preserved in the long term after an arterial switch operation for transposition of the great arteries.

Introduction:Precapillary pulmonary hypertension (pPH) predominantly harms the right ventricle. Still, due to ventricular interdependence, it also affects left ventricular (LV) function. Since LV ejection fraction (EF) is often preserved, more sensitive techniques may be better suited to detect LV dysfunction, such as LA strain or estimation of LV intraventricular pressure gradients (IVPG). However, the value of these techniques in pPH is still unknown.Hypothesis:Cardiovascular magnetic resonance (CMR) derived LA phasic function and LV-IVPG can detect LV dysfunction in pPH patients.Methods:pPH patients (n=31) and healthy controls (n=10), age- and sex-matched, underwent CMR imaging. LA phasic function and the LV-IVPG, calculating the pressure gradient between apex and base throughout the cardiac cycle, were analyzed using standard long-axis cines.Results:LV systolic function, both LVEF as well as the IVPG positive systolic ejection force, was preserved in pPH patients compared to healthy controls (p=0.90, p=0.08 resp.). However, diastolic function in pPH patients was impaired, depicted by 1. lower LA reservoir (patients vs. controls 26% ±9 vs. 37% ±7, p=0.001) and conduit strain (15% ±8 vs. 26% ±7, p=0.001), and 2. an impaired diastolic suction force, and decreased E-wave decelerative force, indicating a weaker passive filling in early to mid-diastole (see Table). Also, 11 pPH patients (35%) showed reversal of IVPG at systolic-diastolic transition, meaning that LV pressure temporarily exceeds LA pressure, whereas none of the healthy controls showed this pattern (p=0.04).Conclusions:pPH impacts LV function by altering diastolic function, demonstrated by an impairment of LA phasic function and LV-IVPG analysis. These parameters could therefore potentially be used as early markers for LV functional decline in pPH patients.