Untersuchung der belastungsabhängigen Adaptation der kardialen Funktion bei Jugendlichen und Erwachsenen mit korrigierter Fallot'scher Tetralogie in der Real Time Magnetresonanz-Tomographie.

Untersuchung der belastungsabhängigen Adaptation der kardialen Funktion bei Jugendlichen und Erwachsenen mit korrigierter Fallot'scher Tetralogie in der Real Time Magnetresonanz-Tomographie.

Examination of the adaptation of the cardiac function in adolescents and adults with corrected Tetralogy of Fallot in Real-Time Magnetic Resonance Tomography.

Thomas Stümpfig

Doctoral thesis

Date of Examination: 2021-04-21

Date of issue: 2021-04-09

Advisor: Steinmetz, Michael Pd Dr.

Referee: Tirilomis, Theodoros Prof. Dr.

Referee: Schön, Margarete Prof. Dr.

Persistent Address: http://hdl.handle.net/21.11130/00-1735-0000-0008-57E8-1

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Abstract

English

Background: Correction of Tetralogy of Fallot (cTOF) often results in pulmonary valve pathology and right ventricular (RV) dysfunction. Reduced exercise capacity in cTOF patients cannot be explained by these findings alone. We aimed to explore why cTOF patients exhibit impaired exercise capacity with the aid of a comprehensive cardio pulmonary exercise testing (CPET) and real-time CMR exercise testing (CMR-ET) protocol. Methods: 33 cTOF patients and 35 matched healthy controls underwent CPET and CMR-ET in a prospective case-control study. Real-time SSFP cine and phase contrast sequences were obtained during incremental supine in-scanner cycling at 50, 70 and 90 Watt. RV and LV volumes and pulmonary flow (Qp) were calculated. Differences of CPET and CMR-ET between cTOF vs. controls and correlations between CPET and CMR-ET parameters in cTOF were evaluated statistically for all CMR exercise levels using Mann-Whitney-U- and Spearman’s-Rank-Order-Correlation tests. Results: CPET capacity was significantly lower in cTOF than in controls. cTOF patients exhibited significantly reduced Qp and RV function, but also lower LV function on CMR-ET. Higher CPET values in cTOF correlated with higher Qp (Qp 90W vs. VE/VCO2%: R= -0.519, p< 0.05), higher LV-EDVi (LV-EDVi at 50W vs. VO2max.% R= 0,452, p < 0.05) and change in LV-EF (LV-EF at 90W vs. Watt %: r= -0,463, p< 0.05). No correlation was found with regard to RV-EF. Significant RV-LV interaction was observed during CMR-ET (RV-EF vs. LV-EF at 50W and 70W: r =0.66, p< 0.02 and r= 0.52, p < 0.05, respectively). Conclusion: Impaired exercise capacity in cTOF resulted from a reduction in not only RV, but also LV function. cTOF with good exercise capacity on CPET demonstrated higher LV reserve and pulmonary blood flow during incremental CMR-ET. Apart from RV parameters, CMR-ET derived LV function could be a valuable tool to stratify cTOF patients for pulmonary valve replacement.

Keywords: Tetralogy of Fallot; exercise stress real time CMR; in scanner exercise; biventricular impairment