Model-Based Comparison of the Normal and Fontan Circulatory Systems—Part III
| Autor: | Alvin J. Chin, Raymond L. Watrous |
|---|---|
| Rok vydání: | 2017 |
| Předmět: |
medicine.medical_specialty
business.industry General Medicine 030204 cardiovascular system & hematology Part iii 03 medical and health sciences Enzyme inhibition 0302 clinical medicine Internal medicine cGMP-specific phosphodiesterase type 5 Pediatrics Perinatology and Child Health Respiration Circulatory system Hypoplastic left heart medicine Cardiology Surgery 030212 general & internal medicine Cardiology and Cardiovascular Medicine Intensive care medicine Endothelin receptor business Guanylate cyclase |
| Zdroj: | World Journal for Pediatric and Congenital Heart Surgery. 8:148-160 |
| ISSN: | 2150-136X 2150-1351 |
| DOI: | 10.1177/2150135116679831 |
| Popis: | Background: For patients with the Fontan circulatory arrangement, angiotensin-converting enzyme inhibition, guanylate cyclase activation, phosphodiesterase 5 inhibition, and endothelin receptor antagonism have so far resulted in little or no improvement in [Formula: see text] or peak cardiac index (CI), suggesting that our understanding of the factors that most impact the exercise hemodynamics is incomplete. Methods: To facilitate comparisons with clinical reports of the exercise performance of preadolescent Fontan patients, we rescaled our previously reported computational models of a two-year-old normal child and similarly aged Fontan patient, extended our Fontan model to capture the nonlinear relationship between flow and resistance quantified from previous computational fluid dynamic analyses of the total cavopulmonary connection (TCPC), and added respiration as well as skeletal muscle contraction. Results: (1) Without respiration, the computational model for both the normal and the Fontan cannot attain the values for CI at peak exercise reported in the clinical literature, (2) because flow through the TCPC is much greater during inspiration than during expiration, the effect on the CI of the dynamic (flow-related) TCPC resistance is much more dramatic during exercise than it is in breath-hold mode at rest, and (3) coupling breathing with skeletal muscle contraction leads to the highest augmentation of cardiac output, that is, the skeletal muscle pump is most effective when the intrathoracic pressure is at a minimum—at peak inspiration. Conclusions: Novel insights emerge when a Fontan model incorporating dynamic TCPC resistance, full respiration, and skeletal muscle contraction can be compared to the model of the normal. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|