Exercise stress CMR reveals reduced aortic distensibility and impaired right-ventricular adaptation to exercise in patients with repaired tetralogy of Fallot

Abstract

BackgroundThe aim of our study was to evaluate the feasibility of exercise cardiac magnetic resonance (CMR) in patients with repaired tetralogy of Fallot (RTOF) and to assess right and left ventricular adaptation and aortic wall response to exercise in comparison with volunteers.Methods11 RTOF and 11 volunteers underwent prospective CMR at rest and during exercise. A supine bicycle ergometer was employed to reach twice the resting heart rate during continuous exercise, blood pressure and heart rate were recorded. Bi-ventricular parameters and aortic stiffness were assessed using accelerated cine sequences and flow-encoding CMR. A t-test was used to compare values between groups. A Mann Whitney test was used to compare values within groups.ResultsIn RTOF both ventricles showed an impaired contractile reserve (RVEF rest 36.2±8.3%, +1.3±3.9% increase after exercise; LVEF rest 53.8±6.1%, +5.7±6.4% increase after exercise) compared to volunteers (RVEF rest 50.5±5.0%, +10.4±7.1% increase after exercise, p = 0.039; LVEF rest 61.9±3.1%, +12.2±4.7% increase after exercise, p = 0.014).RTOF showed a reduced distensibility of the ascending aorta during exercise compared to volunteers (RTOF: 3.4±1.9 10-3.mmHg-1 vs volunteers: 5.1±1.4 10-3.mmHg-1; p = 0.027). Ascending aorta distensibility was correlated to cardiac work in the volunteers but not in RTOF.ConclusionRTOF showed an impaired contractile reserve for both ventricles. The exercise unmasked a reduced distensibility of the ascending aorta in RTOF, which may be an early sign of increased aortic rigidity.

Exercise cardiovascular magnetic resonance: development, current utility and future applications

“…The seminal Ex-CMR study in repaired ToF patients by Roest et al demonstrated an abnormal RV response to exercise compared with controls, but a decrease in pulmonary regurgitation [117]. A more recent study demonstrated reduced biventricular contractile reserve and aortic distensibility in repaired ToF patients compared to healthy subjects during Ex-CMR, which may be an early sign of increased aortic rigidity [121].…”

“…Ex-CMR has been demonstrated as feasible in repaired ToF in both adults [121] and children [85]. The seminal Ex-CMR study in repaired ToF patients by Roest et al demonstrated an abnormal RV response to exercise compared with controls, but a decrease in pulmonary regurgitation [117].…”

“… Tang (2017) [ 120 ] 47 Fontan circulation/TCPC SVC, ascending and descending aortic flows Moderate/ to VAT Free breathing Exercise cessation Fontan patients with a smaller TCPC diameter index (which accounts for narrowing’s in the TCPC circulation) demonstrate increased indexed power loss and worse exercise performance. Habert (2018) [ 121 ] 22 Repaired ToF (11) Control (11) Biventricular volumes & aortic distensibility Low-moderate Breath hold exercise cease Repaired ToF demonstrated reduced bi-ventricular contractile reserve and reduced ascending aortic distensibility vs controls. Helsen (2018) [ 80 ] 45 Atrial corrected-TGA (23) CC-TGA (10) Control (12) Systemic ventricle volumes Maximal Un-gated real time, free-breathing.…”

Pressure-Volume Relationship By Pharmacological Stress Cardiovascular Magnetic Resonance

“…Moreover, CMR by late gadolinium enhancement (LGE) is the noninvasive reference standard for replacement brosis detection, with signi cant diagnostic and prognostic implications. Pharmacological stress-CMR can be performed using either inotropic (dobutamine) or vasodilator (adenosine or dipyridamole) stimuli [17] and recent studies have demonstrated the feasibility of exercise stress test, acquiring images immediately following maximal treadmill exercise or with in-scanner cycle ergometers [18,19]. Nevertheless, currently vasodilator stress agents remain the mainstay of stress-CMR due to safety issues [20].…”

Pressure–volume relationship by pharmacological stress cardiovascular magnetic resonance

“…Moreover, CMR by late gadolinium enhancement (LGE) is the noninvasive reference standard for replacement brosis detection, with signi cant diagnostic and prognostic implications. Pharmacological stress-CMR can be performed using either inotropic (dobutamine) or vasodilator (adenosine or dipyridamole) stimuli [17] and recent studies have demonstrated the feasibility of exercise stress test, acquiring images immediately following maximal treadmill exercise or with in-scanner cycle ergometers [18,19]. Nevertheless, currently vasodilator stress agents remain the mainstay of stress-CMR due to safety issues [20].…”