Flow-dynamics assessment of mitral-valve surgery by intraoperative vector flow mapping

Akiyama, Koichi; Nakamura, Norimasa; Naito, Yoshiro; Kinoshita, Mao; Shimizu, Masaru; Hamaoka, Saeko; Kato, Hideya; Yanagimoto, Hiroaki; Nakajima, Yasufumi; Mizobe, Toshiki; Numata, Shusuke; Sawa, Teiji

doi:10.1093/icvts/ivx033

Cited by 33 publications

(39 citation statements)

References 27 publications

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“…8À11 After mitral valve replacement, the vorticial flow patterns are disrupted and energy loss increases. 8,12 How the physiologic flow patterns are disrupted depends on both the type of mitral prosthesis used and the prosthetic valve orientation. 13À15 Mitral repairs in contrast to prosthetic mitral valves maintain a closer to physiologic vorticial flow pattern in the left ventricle and are associated with decreased energy loss.…”

Section: Left Ventricular Vortex Formationmentioning

confidence: 99%

Inverted Aortic Prosthesis in the Mitral Position: Is Upside Down Always the Right Side Up?

Khoche

Cobey

2019

Journal of Cardiothoracic and Vascular Anesthesia

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Section: Left Ventricular Vortex Formationmentioning

confidence: 99%

Inverted Aortic Prosthesis in the Mitral Position: Is Upside Down Always the Right Side Up?

Khoche

Cobey

2019

Journal of Cardiothoracic and Vascular Anesthesia

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“…Modern imaging modalities later confirmed vortical flow patterns to be a common feature in the heart, where vortices appear during diastole, associated with a smooth redirection of flow from the inflow to the outflow tract. It is argued that these specific flow patterns allow for kinetic energy preservation for subsequent ejections and are disturbed in patients with myocardial infarction, dilated cardiomyopathy or heart failure as well as after surgical valve interventions . It has been shown that the contribution of the diastolic vortex ring to diastolic left ventricular filling is significantly decreased in abnormal ventricles .…”

Section: Introductionmentioning

confidence: 99%

“…It is argued that these specific flow patterns allow for kinetic energy preservation for subsequent ejections 5,6 and are disturbed in patients with myocardial infarction, dilated cardiomyopathy or heart failure 7,8 as well as after surgical valve interventions. 9 It has been shown that the contribution of the diastolic vortex ring to diastolic left ventricular filling is significantly decreased in abnormal ventricles. 10 Based on their findings at resting heart rates, it was hypothesized that the vortex contribution to ventricular filling is increased during exercise.…”

Section: Introductionmentioning

confidence: 99%

Left ventricular blood flow patterns at rest and under dobutamine stress in healthy pigs

et al. 2018

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Intracardiac blood flow patterns are affected by the morphology of cardiac structures and are set up to support the heart's pump function. Exercise affects contractility and chamber size as well as pre‐ and afterload. The aim of this study was to test the feasibility of four‐dimensional phase contrast cardiovascular MRI under pharmacological stress and to study left ventricular blood flow under stress. 4D flow data were successfully acquired and analysed in 12 animals. During dobutamine infusion, heart rate and ejection fraction increased (82 ± 5 bpm versus 124 ± 3 bpm/46 ± 9% versus 65 ± 7%; both p < 0.05). A decrease in left ventricular end‐diastolic volume (72 ± 14 mL versus 55 ± 8 mL; p < 0.05) and end‐systolic volume (40 ± 15 mL versus 19 ± 6 mL; p < 0.05) but no change in stroke volume were observed. Trans‐mitral diastolic inflow velocity increased under dobutamine and the trajectory of inflowing blood was directed towards the anterior septum with increased inflow angle (26 ± 5°) when compared with controls (15 ± 2°). In 5/6 animals undergoing stress diastolic vortices developed later, and in 3/6 animals vortices collapsed earlier with significantly smaller cross‐sectional area during diastole. The vorticity index was not affected. Under the stress condition direct flow (% ejection within the next heart beat) increased from 43 ± 6% to 53 ± 8%. 4D MRI blood flow acquisition and analysis are feasible in pig hearts under dobutamine‐induced stress. Flow patterns characterized by high blood velocity and antero‐septally oriented diastolic inflow as well as decreased ventricular volumes are unfavourable conditions for diastolic vortex development under pharmacological stress, and cardiac output is increased by a rise in heart rate and directly ejected left ventricular blood volume.

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“…EL elevates at sites where velocity vectors change the magnitude and direction. Such as, EL is probably to increase within turbulent flow, like at a point after mitral valve replacement . The endocardial border was manually traced at the maximal volumes of LA, and then automatically obtained for remaining frames.…”

Section: Methodsmentioning

confidence: 99%

“…Such as, EL is probably to increase within turbulent flow, like at a point after mitral valve replacement. 13 The endocardial border was manually traced at the maximal volumes of LA, and then automatically obtained for remaining frames. After automatically tracing, EL (measurement in N/(m·s)) was assessed at every frame.…”

Section: Analysis Of Energy Lossmentioning

confidence: 99%

Successful catheter ablation of atrial fibrillation improves but not reverses the abnormalities of left atrial mechanics and energy loss

Lin

Cao

et al. 2019

Echocardiography

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Background Dissipative energy loss (EL), a new index to quantify the inefficient blood flow, has not been explored within left atrium (LA) in patients with atrial fibrillation (AF). We aimed to study the intra‐atrial flow and mechanics in patients with AF before and after successful catheter ablation by evaluating EL and LA global longitudinal strain (LAS). Methods In our study, there were 53 patients undergoing catheter ablation for AF at baseline (AF group) and 33 age‐ and sex‐matched controls. They were both assessed of LA EL using vector flow mapping (VFM) and of LAS using two‐dimensional tracking (2DTT) during systole (sys), early diastole (ed), and atrial contraction phase (ac). Out of 53 patients, 37 patients who sustained sinus rhythm and carried out the echocardiographic examination at 3 and 6 months follow‐up were evaluated of change in EL and LAS. The independent predictors of EL during three phases in AF group were performed using stepwise multivariate linear regression analyses. Results Left atrium EL and LAS among all phases in AF group were significantly lower than controls (all P < 0.01). During follow‐up, LASsys and LASac both significantly improved at 3 and 6 months (both P < 0.01), and ELac significantly increased after 6 months (P < 0.05); ELsys, ELed and LASed were no significant change; EL and LAS among all phases were no normalized during follow‐up. The independent predictors of EL were: for ELsys, BSA (P = 0.004) and LASac (P = 0.025); for ELed, E (P = 0.001) and A (P = 0.014); for ELac, E/A (P < 0.001). Conclusion Vector flow mapping and 2DTT revealed impaired intra‐atrial flow and mechanics. Successful catheter ablation for AF slightly improves but not reverses the aforementioned impairment, indicating the continuous LA dysfunction.

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Flow-dynamics assessment of mitral-valve surgery by intraoperative vector flow mapping

Abstract: Mitral valve replacement alters the intraventricular vortex pattern and increases flow energy loss. A small mitral-septal angle is a risk factor for abnormal vortex patterns after mitral valve repair surgery.

Cited by 33 publications

References 27 publications

Inverted Aortic Prosthesis in the Mitral Position: Is Upside Down Always the Right Side Up?

Inverted Aortic Prosthesis in the Mitral Position: Is Upside Down Always the Right Side Up?

Left ventricular blood flow patterns at rest and under dobutamine stress in healthy pigs

Successful catheter ablation of atrial fibrillation improves but not reverses the abnormalities of left atrial mechanics and energy loss

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