scholarly journals Peak flow measurements in patients with severe aortic stenosis: a prospective comparative study between cardiovascular magnetic resonance 2D and 4D flow and transthoracic echocardiography

2021 ◽  
Vol 23 (1) ◽  
Author(s):  
Reetta Hälvä ◽  
Satu M. Vaara ◽  
Juha I. Peltonen ◽  
Touko T. Kaasalainen ◽  
Miia Holmström ◽  
...  
Keyword(s):  
Cardiovascular Magnetic Resonance ◽  
Magnetic Resonance ◽  
Aortic Valve ◽  
Flow Velocity ◽  
Peak Flow ◽  
Valvular Disease ◽  
Limits Of Agreement ◽  
4D Flow ◽  
Peak Flow Velocity ◽  
2D Flow

Abstract Background Aortic valve stenosis (AS) is the most prevalent valvular disease in the developed countries. Four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) is an emerging imaging technique, which has been suggested to improve the evaluation of AS severity compared to two-dimensional (2D) flow and transthoracic echocardiography (TTE). We investigated the reliability of CMR 2D flow and 4D flow techniques in measuring aortic transvalvular peak systolic flow in patients with severe AS. Methods We prospectively recruited 90 patients referred for aortic valve replacement due to severe AS (73.3 ± 11.3 years, aortic valve area 0.7 ± 0.1 cm2, and 54/36 tricuspid/bicuspid), and 10 non-valvular disease controls. All the patients underwent echocardiography and 2D flow and 4D flow CMR. Peak flow velocity measurements were compared using Wilcoxon signed rank sum test and Bland–Altman analysis. Results 4D flow underestimated peak flow velocity in the AS group when compared with TTE (bias − 1.1 m/s, limits of agreement ± 1.4 m/s) and 2D flow (bias − 1.2 m/s, limits of agreement ± 1.6 m/s). The differences between values obtained by TTE (median 4.3 m/s, range 2.7–6.1 m/s) and 2D flow (median 4.5 m/s, range 2.9–6.5 m/s) compared to 4D flow (median 3.1 m/s, range 1.7–5.1 m/s) were significant (p < 0.001). The difference between 2D flow and TTE were insignificant (bias 0.07 m/s, limits of agreement ± 1.5 m/s). In non-valvular disease controls, peak flow velocity was measured higher by 4D flow than 2D flow (1.4 m/s, 1.1–1.7 m/s and 1.3 m/s, 1.1–1.5 m/s, respectively; bias 0.2 m/s, limits of agreement ± 0.16 m/s). Conclusions CMR 4D flow significantly underestimates systolic peak flow velocity in patients with severe AS. 2D flow, in turn, estimated the AS velocity accurately, with measured peak flow velocities comparable to TTE.

scholarly journals CMR 4D flow underestimates peak systolic flow measurements in patients with severe aortic stenosis

2021 ◽  
Vol 22 (Supplement_1) ◽  
Author(s):  
R Halva ◽  
J Peltonen ◽  
T Kaasalainen ◽  
J Lommi ◽  
S Suihko ◽  
...  
Keyword(s):  
Aortic Valve ◽  
Aortic Stenosis ◽  
Peak Flow ◽  
Aortic Valve Area ◽  
Limits Of Agreement ◽  
4D Flow ◽  
Flow Measurements ◽  
4D Flow Cmr ◽  
2D Flow ◽  
The Difference

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): Helsinki University Hospital, Finland Background Aortic stenosis (AS) is the most prevalent valvular disease in the developed countries. 4D flow is an emerging cardiac magnetic resonance (CMR) imaging technique, which has been suggested to improve the evaluation of AS severity. The accuracy of peak flow measurement by 4D flow CMR in patients with severe AS has, however, remained unvalidated. Purpose We investigated the reliability of the novel 4D flow CMR technique in measuring transvalvular peak systolic flow in patients with severe aortic valve stenosis. Methods The study included 63 patients clinically evaluated for valve replacement due to severe symptomatic AS. All the patients underwent echocardiography, 2D phase-contrast and 4D flow CMR. CMR was performed on consecutive patients according to international guidelines. Mean age of the patients was 73.8 ± 11.5 years, mean aortic valve area 0.7 ± 0.2 cm², and 40 of the valves were tricuspid and 23 bicuspid. QFlow and QFlow 4D software were used for flow analyses. Bland-Altman analyses and Wilcoxon signed rank sum tests were performed using SPSS software. Results CMR 4D flow analyses underestimated peak flow values when compared with echocardiography (bias -1.1 m/s, limits of agreement ± 1.5 m/s) and with 2D flow analyses (bias -1.2 m/s, limits of agreement ± 1.7 m/s). The difference between values obtained by 4D flow (median 3.1 m/s, range 1.5 – 4.9 m/s) and echocardiography (median 4.3 m/s, range 2.1 – 6.1 m/s) as well as by 2D flow (median 4.3 m/s, range 2.0 – 8.4 m/s) were statistically significant (p &lt; 0,001). The difference between 2D flow analyses and echocardiography remained statistically insignificant (bias 0.05 m/s, limits of agreement ± 1.6 m/s). Conclusions We found that 4D flow analysis significantly underestimates systolic peak flow values in patients with severe AS. This may be due to intra-voxel averaging of the narrow jets. In contrast to previous assumptions, traditional 2D flow technique may therefore outperform 4D flow in measuring valvular peak flow by CMR in patients with severe AS. This should be taken into consideration when assessing disease severity by CMR. Abstract Figure. Peak systolic flow in AS patients (n = 63)

scholarly journals Altered left atrial 4D flow characteristics in patients with paroxysmal atrial fibrillation in the absence of apparent remodeling

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ahmet Demirkiran ◽  
Raquel P. Amier ◽  
Mark B. M. Hofman ◽  
Rob J. van der Geest ◽  
Lourens F. H. J. Robbers ◽  
...  
Keyword(s):  
Atrial Fibrillation ◽  
Sinus Rhythm ◽  
Flow Velocity ◽  
Paroxysmal Atrial Fibrillation ◽  
Left Atrial ◽  
Peak Flow ◽  
Thrombus Formation ◽  
Clinical Value ◽  
4D Flow ◽  
Ssfp Cine

AbstractThe pathophysiology behind thrombus formation in paroxysmal atrial fibrillation (AF) patients is very complex. This can be due to left atrial (LA) flow changes, remodeling, or both. We investigated differences for cardiovascular magnetic resonance (CMR)-derived LA 4D flow and remodeling characteristics between paroxysmal AF patients and patients without cardiac disease. In this proof-of-concept study, the 4D flow data were acquired in 10 patients with paroxysmal AF (age = 61 ± 8 years) and 5 age/gender matched controls (age = 56 ± 1 years) during sinus rhythm. The following LA and LA appendage flow parameters were obtained: flow velocity (mean, peak), stasis defined as the relative volume with velocities < 10 cm/s, and kinetic energy (KE). Furthermore, LA global strain values were derived from b-SSFP cine images using dedicated CMR feature-tracking software. Even in sinus rhythm, LA mean and peak flow velocities over the entire cardiac cycle were significantly lower in paroxysmal AF patients compared to controls [(13.1 ± 2.4 cm/s vs. 16.7 ± 2.1 cm/s, p = 0.01) and (19.3 ± 4.7 cm/s vs. 26.8 ± 5.5 cm/s, p = 0.02), respectively]. Moreover, paroxysmal AF patients expressed more stasis of blood than controls both in the LA (43.2 ± 10.8% vs. 27.8 ± 7.9%, p = 0.01) and in the LA appendage (73.3 ± 5.7% vs. 52.8 ± 16.2%, p = 0.04). With respect to energetics, paroxysmal AF patients demonstrated lower mean and peak KE values (indexed to maximum LA volume) than controls. No significant differences were observed for LA volume, function, and strain parameters between the groups. Global LA flow dynamics in paroxysmal AF patients appear to be impaired including mean/peak flow velocity, stasis fraction, and KE, partly independent of LA remodeling. This pathophysiological flow pattern may be of clinical value to explain the increased incidence of thromboembolic events in paroxysmal AF patients, in the absence of actual AF or LA remodeling.

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