Neue spiroergometrische Testvariablen zur Entscheidungshilfe bei Pulmonalklappenersatz

Document Type
Doctoral Thesis
Granting Institution
Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Medizinische Fakultät
Issue Date
Deindl, Ruth
  1. Abstract 1.1 Background and Objectives

Pulmonary valve insufficiency is a frequently encountered finding in the long-term course of patients following surgical correction of Tetralogy of Fallot or interventions on the pulmonary valve, often necessitating pulmonary valve replacement (PVR). The challenge lies in determining the appropriate timing for valve replacement to achieve a sustainable long-term outcome. The goal is to minimize the risk of subsequent interventions while preventing irreversible damage due to valve insufficiency. Various diagnostic criteria contribute to the decision-making for optimal PVR timing, incorporating findings from electrocardiography, echocardiography, magnetic resonance imaging and cardiopulmonary exercise testing. Decision-making can be particularly challenging for subjectively asymptomatic patients with borderline findings. This study focuses on highlighting cardiopulmonary exercise testing to discuss whether patients with PI differ from a control group without PI based on the collected data.

1.2 Methods (Patients, Materials, and Examination Methods)

In this study, examination results related to ECG (QRS complex width and R-wave amplitude in right precordial lead), MRI (ventricular volume, extent of PI), and cardiopulmonary exercise testing of a patient group with PI (n=45) were retrospectively compared with a control group (n=25) without PI. For evaluating the cardiac output immediately prior as well as after peak exercise new slopes and durations investigating the behaviour of the stroke volume were introduced.

1.3 Results and Observations

Both groups were comparable with regards to sex (20% females in the PI group vs. 12% in the control group), and age (mean age of 18.5 years vs. 18.1 years in the control group). Known associations between PI and impaired right ventricular function were confirmed in the investigated MRI, ECG, and echocardiography parameters. No significant differences existed between the two groups for all the classical values of cardiopulmonary exercise testing. However, the post-exertional oxygen pulse showed a delayed decline in comparison with the control group.

1.4 2.4 Practical Conclusions and Discussions

The results underscore the relevance of cardiopulmonary exercise testing as a method for objectifying the cardiopulmonary fitness of patients with PI. After peak exercise, the stroke volume usually declines rapidly. However, if the ventricle cannot achieve peak output due to regurgitation or as a consequence of diminished power after ventricular remodeling, peak cardiac output cannot be achieved. This becomes visible as the cardiac output remains high even after the load has been removed. This study clearly how a noticeably altered O2pulse responds after peak exercise in patients with PI. The fact that the duration of the O2pulse remains high during the recovery period could represent an additional tool for determining the optimal timing for PVR. Prospective studies need to assess its viability.

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