Interventioneller Pulmonalklappenersatz bei Patienten mit angeborenem Herzfehler und Pulmonalklappenvitium - eine MRT-Studie
Interventional Pulmonary Valve Replacement in Patients with Congenital Heart Disease and Pulmonary Valve Dysfunction - An MRI Study
by Carla Charlotte Hölzer
Date of Examination:2023-08-15
Date of issue:2023-08-09
Advisor:PD Dr. Michael Steinmetz
Referee:PD Dr. Michael Steinmetz
Referee:Prof. Dr. Christina Unterberg-Buchwald
Persistent Address:
http://dx.doi.org/10.53846/goediss-10040
Files in this item
Name:Dissertation_CCH_030823_upload.pdf
Size:11.0Mb
Format:PDF
The following license files are associated with this item:
Abstract
English
Patients with corrected congenital heart defects now survive into adulthood thanks to modern surgical and interventional procedures. Due to these medical advancements, the number of adults with congenital heart defects now exceeds that of children with congenital heart defects at a ratio of 2:1. This shift in demographics has led to the emergence of previously unknown late and long-term complications (Marelli et al., 2014). Therefore, it is crucial to establish adequate follow-up and early detection protocols, which include a comprehensive medical history, clinical examination, assessment of subjective physical tolerance, as well as a meaningful quantification and qualification of objective heart function. Cardiac function can be determined using various parameters and testing methods, but the cardiac magnetic resonance imaging (MRI) has gained significant importance in recent years. Myocardial deformation parameters, such as strain and strain rate, have proven to be more sensitive and informative compared to parameters like ejection fraction (EF) and other global measures, as they are less dependent on the examination and less time-consuming. The technique of feature tracking (FT) has made specialized sequences, such as MR tagging, unnecessary. The aim of this dissertation was to detect and identify prognostic markers for cardiac changes after an interventional pulmonary valve replacement (PPVI), particularly regarding FT parameters of all four heart chambers. The majority of patients were individuals with corrected Tetralogy of Fallot who subsequently developed pulmonary valve stenosis. The results of this study show that even with normal performance and EF, changes in FT parameters can be detected before PPVI. Furthermore, the changes after PPVI can be better quantified and qualified using strain and strain rate compared to only marginally altered EF, W/kgKG, and VO2max. In summary, the study demonstrated a significant increase in longitudinal strain in both ventricles after PPVI. Additionally, there was an increase in time to peak strain for the right ventricle, while the strain rate of the left ventricle and the peak strain of the left atrium also significantly improved. Regarding the volumetric assessment of cardiac function, comparing pre- to post-PPVI, the left heart showed an increase in EF, cardiac index (CI), stroke volume index (SVi), left ventricular end-diastolic volume index (LV EDVi), and systolic left atrial volume. However, there were no significant changes in the volumetry of the right heart. Notably, the deformation parameters better reflect the reduced RV burden and improved ventricular function resulting from PPVI compared to global indices or volumetry. Thus, the study suggests that for congenital heart defects, deformation analysis provides a more sensitive description of cardiac function than volumetric analysis. When considering pre-interventional deformation parameters based on the patient's gender, it was observed that women have higher peak strain, higher time to peak strain, and higher strain rate of the left ventricle compared to men. Due to these significant differences, it should be considered to develop gender-specific thresholds and indication criteria for PPVI. However, the effect of PPVI appears to be similar for both genders based on the available data. In conclusion, the deformation parameters can depict the impact of PPVI on both sides of the heart and are thus more sensitive parameters, potentially useful for stratifying patients into risk groups or supporting the indication for valve replacement in a more detailed manner. A next step would be the establishment of gender-specific thresholds and indication criteria based on deformation parameters.
Keywords: corrected congenital heart defects; PPVI; feature tracking; myocardial deformation parameter
