A novel parameter for pulmonary blood flow during palliative procedures: velocity time integral of the pulmonary vein†

Abstract Children with sleep disordered breathing (SDB) have evidence of increased blood flow velocity and sympathetic overactivity. Sympathetic overactivity leads to peripheral vasoconstriction, increased vascular resistance and consequently, increases blood flow velocity. Early vascular ageing involves premature arterial thickening and stiffening that leads to changes in vascular function. Both increased blood flow velocity and sympathetic overactivity are promoters of arterial remodelling and hence, early vascular ageing. No studies have directly histologically investigated arterial wall structure in children with SDB and how it relates to vascular function. Thirty-six children scheduled for tonsillectomy underwent polysomnography to determine SDB severity and resting brachial artery blood flow velocity (velocity time integral and peak systolic velocity) using Doppler ultrasound. The dorsal lingual artery (tonsil) was stained using hematoxylin and eosin techniques to examine arterial wall structures. Increased velocity time integral correlated with increased arterial medial thickness (r = 0.50, P<0.01), arterial smooth muscle cells (r =0.43, P<0.05) and arterial smooth muscle layers (r=0.45, P<0.01). These relationships remained significant after controlling for body-mass index (BMI). Increased BMI was associated with increased velocity time integral (r=0.61, P<0.01), arterial medial thickness (r=0.37, P<0.05) and arterial medial area (r=0.36, P<0.05). SpO2nadir (TST/REM) was inversely associated with arterial medial area (r=-0.35; r=-0.38, P<0.05). These results demonstrate that increased blood flow velocity is associated with changes in arterial wall composition in children with SDB. This suggests that paediatric SDB, a treatable disorder, is potentially a modifiable risk factor for early vascular ageing and resultant cardiovascular disease in adulthood.

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Studies on Pulsed-wave Doppler Echocardiographic Parameters of Blood Flow through Mitral, Tricuspid and Aortic Valves in Healthy Indian Spitz Dogs

Indian Journal of Animal Research ◽

10.18805/ijar.b-4256 ◽

2021 ◽

Author(s):

Deepti Bodh ◽

Mozammel Hoque ◽

Abhishek Chandra Saxena

Keyword(s):

Blood Flow ◽

Wave Velocity ◽

Doppler Echocardiography ◽

Aortic Valves ◽

Velocity Time Integral ◽

Wave Velocities ◽

Time Integral ◽

Pulsed Wave Doppler ◽

Flow Through ◽

Isovolumic Relaxation

Background: Pulsed-wave Doppler measures blood flow at specific point and provides information on velocity, direction and uniformity of blood flow throughout cardiac cycle. Till date, there is no published data on study of cardiac parameters using pulsed-wave Doppler echocardiography in Indian Spitz dogs.Methods: Twenty-four clinically normal Indian Spitz dogs were subjected to pulsed-wave Doppler echocardiography to determine the reference intervals for Doppler parameters of blood flow through mitral, tricuspid and aortic valves. Mitral peak E and A-wave velocities, E/A ratio, deceleration time, isovolumic relaxation time, E and A-wave velocity time integral, E duration and A duration were 0.69±0.09 m/s, 0.43±0.12 m/s, 1.69±0.45, 111.25±35.94 ms, 48.50±24.77 ms, 0.07±0.01 m and 0.04±0.02 m, 196.88±44.38 ms and 181.25±64.89 ms, respectively. Tricuspid peak E and A-wave velocities, E/A ratio and E and A-wave velocity time integral were 0.57±0.11 m/s, 0.38±0.08 m/s, 1.56±0.32 and 0.07±0.02 m and 0.05±0.01 m, respectively. Aortic peak velocity, velocity time integral and ejection time were 0.87±0.07 m/s, 0.11±0.02 m and 0.25±0.04 s, respectively. Conclusion: The reference values of flow parameters across mitral, tricuspid and aortic valves using pulsed-wave Doppler echocardiography were determined. Mitral, tricuspid and aortic valve flow variables were unaffected by gender whereas isovolumic relaxation correlated positively with body weight.

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