Aortic flow conditions predict ejection efficiency in the NHLBI-Sponsored Women's Ischemia Syndrome Evaluation (WISE).
| Autor: | Doyle M; Allegheny General Hospital, Pittsburgh, PA, USA., Pohost GM; Keck Medical Center, University of Southern California, Los Angeles, CA, USA., Bairey Merz CN; Barbra Streisand Women's Heart Center, Cedars-Sinai Heart Institute, Los Angeles, CA, USA., Farah V; Allegheny General Hospital, Pittsburgh, PA, USA., Shaw LJ; Barbra Streisand Women's Heart Center, Cedars-Sinai Heart Institute, Los Angeles, CA, USA., Sopko G; National Heart Lung and Blood Institute, NIH, Bethesda, MD, USA., Rogers WJ; the University of Alabama at Birmingham, AL, USA., Sharaf BL; Brown University, Providence, RI, USA., Pepine CJ; University of Florida, Gainesville, FL, USA., Thompson DV; Allegheny General Hospital, Pittsburgh, PA, USA., Rayarao G; Allegheny General Hospital, Pittsburgh, PA, USA., Tauxe L; the University of Alabama at Birmingham, AL, USA., Kelsey SF; Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA., Biederman RWW; Allegheny General Hospital, Pittsburgh, PA, USA. |
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| Jazyk: | angličtina |
| Zdroj: | Cardiovascular diagnosis and therapy [Cardiovasc Diagn Ther] 2017 Jun; Vol. 7 (3), pp. 288-295. |
| DOI: | 10.21037/cdt.2017.03.07 |
| Abstrakt: | Background: The Windkessel model of the cardiovascular system, both in its original wind-chamber and flow-pipe form, and in its electrical circuit analog has been used for over a century to modeled left ventricular ejection conditions. Using parameters obtained from aortic flow we formed a Flow Index that is proportional to the impedance of such a "circuit". We show that the impedance varies with ejection fraction (EF) in a manner characteristic of a resonant circuit with multiple resonance points, with each resonance point centrally located in a small range of EF values, i.e., corresponding to multiple contiguous EF bands. Methods: Two target populations were used: (I) a development group comprising male and female subjects (n=112) undergoing cardiovascular magnetic resonance (CMR) imaging for a variety of cardiac conditions. The Flow Index was developed using aortic flow data and its relationship to left ventricular EF was shown. (II) An illustration group comprised of female subjects from the Women's Ischemia Syndrome Evaluation (WISE) (n=201) followed for 5 years for occurrence of major adverse cardiovascular events (MACE). Flow data was not available in this group but since the Flow Index was related to the EF we noted the MACE rate with respect to EF. Results: The EFs of the development population covered a wide range (9%-76%) traversing six Flow Index resonance bands. Within each Flow Index resonance band the impedance varied from highly capacitive at the lower range of EF through minimal impedance at resonance, to highly inductive at the higher range of EF, which is characteristic of a resonant circuit. When transitioning from one EF band to a higher band, the Flow Index made a sudden transition from highly inductive to capacitive impedance modes. MACE occurred in 26 (13%) of the WISE (illustration) population. Distance in EF units (Delta Conclusions: A Flow Index that describes impedance conditions of left ventricular ejection can be calculated using data obtained completely from the ascending aorta. The Flow Index exhibits a periodic variation with EF, and in a separate illustration population the occurrence of MACE was observed to exhibit a similar periodic variation with EF, even in cases of normal EF. Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare. |
| Databáze: | MEDLINE |
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