Rheology of Sclerosant Foam in in-vitro.

M.Phil in Mechanical EngineeringKAICHUNG WONG | SID : 310334209

Nature of Varicose Vein

› Varicose veins are chronic abnormally dilated veins, usually involving the superficial veins of the upper and lower leg (Kumar et al., 2007).

› The function of healthy veins are carry blood towards the heart with flow driven by muscle movements around the vein, with flow directed by bicuspid valves which regulate the blood flow in one direction.

Kumar V, Abbas A, Fausto N, R M. Robbins Basic Pathology, 8th edition. In: Kumar V, editor.: Saunders Elsevier; 2007. p. 370.

Clinical Treatment

› Sclerotherapy- Foam sclerotherapy is to treat varicose veins and rarer venous

conditions such as venous malformations (Bergen et al., 2006; Redendo et al., 2009; Rehman et al., 2009).

- Sodium Tetradecyl Sulphate (STS) and Polidocanol (POL) injure the endothelial cell membrane phospholipid bilayer, transforming the venous structure into a fibrous cord that cannot be recanalized (Redendo et al., 2005).

Bergan J, Pascarella L, Mekenas L. Venous disorders: treatment with sclerosant foam. J Cardiovasc Surg. [Review]. 2006 Feb;47(1):9-18.

Redondo P, Bastarrika G, Sierra A, Martinez-Cuesta A, Cabrera J. Efficacy and Safety of Microfoam Sclerotherapy in a Patient With Klippel-Trenaunay Syndrome and a Patent

Foramen Ovale. Arch Dermatol. [Article]. 2009 Oct;145(10):1147-51.

Rehman KU, Sittampalam G, McCafferty I, Monaghan A. The use of foam sclerotherapy for the treatment of head and neck vascular malformations. Br J Oral Maxillofac Surg.

[Article]. 2009 Dec;47(8):631-2.

Redondo P, Cabrera J. Microfoam sclerotherapy. Semin Cutan Med Surg. [Article]. 2005 Dec;24(4):175-83.

Clinical Treatment

- The best foam was produced by mixing one part liquid STS and four parts air (Tessari et al, 2001).

- Injection of foam introduces air into the circulation which can lead to serious complications caused by air emboli. Such complications of foam sclerotherapy include both reversible events and serious events such as stroke. (Forlee et all, 2006; Bush et al, 2008; Hahn et al, 2010).

TESSARI, L., CAVEZZI, A. and FRULLINI, A., (2001) Preliminary experience with a new sclerosinhg foam in the treatment of varicose veins. Dermatol. Surg., 27, 58 – 60.

Forlee, M.V., Grouden, M., Moore, D.J., Shanik, G. Stroke after varicose vein foam injection sclerotherapy. J Vasc Surg. [Article]. 2006 Jan;43(1):162-4.

Bush, R.G., Derrick, M., Manjoney, D. Major neurological events following foam sclerotherapy. Phlebology. [Article]. 2008;23(4):189-92.

Hahn, M., Schulz, T., Junger. M. Late stroke after foam sclerotherapy. Vasa. [Article]. 2010 Feb;39(1):108-10.

Foam Generation

Courtesy : http://www.bassclerotherapy.co.uk/index.php?mact=News,cntnt01,print,0&cntnt01articleid=16&cntnt01showtemplate=false&cntnt01returnid=15

Project Aims

› Determine the basic physical properties of Sclerosants in liquid and foam form which include: viscosity, surface tension and density by means of performing experiments at University laboratories. These data will be essential for computational works.

› To understand the flow behaviour of sclerosants liquid and Sclerosants foam and blood in the Saphenofemoral Junction (SFV) with and without angle by means of computational model and experimental model.

Basic Physical Properties

• Density measurement– Weight with fixed and expansion volume method

• Pipette (Gilson Pipetman P1000) and digital balance (Sartorius – Analytic – A200S)

• Surface Tension Measurement– Du Nuoy Ring method

• KSV Sigma 70 Surface Tensiometer.

• Viscosity Measurement– Parallel Plates method

• Physica MCR 301.

CFD Model

› Numerical Analysis:- Commercial CFD Software – ANSYS 13.0- Workstation

Refined Sapherofemoral Junction Case

Experimental Model

POL Density

0.0 0.5 1.0 1.5 2.0 2.5 3.0960

970

980

990

1000

1010

1020

986.57988.32987.48

993.72993.88995.64

1006.91

Density with different POL Concentration

Concentration (%)

Den

sity

(kg

/m3)

STS Density

0.0 0.5 1.0 1.5 2.0 2.5 3.0960

970

980

990

1000

1010

1020

1006.32

988.94991.30

993.24994.48

996.32

1006.91

Density for different STS Concentration

Concentration (%)

Den

sity

(kg

/m3)

Foam Density Measurement

POL CMC and Surface Tension Measurement

-39.144-5.035-4.734-4.258-3.974-3.753-3.568-3.413-3.281-3.151-3.028-2.918-2.814-2.720-2.634-2.554-2.476-2.408-2.346-2.285-2.228-2.174-2.125-2.075-2.027-1.984-1.941-1.898-1.857-1.819-1.783-1.749-1.717-1.684-1.654-1.624-1.593-1.564-1.538-1.511-1.484-1.458-1.433-1.407-1.383-1.359-1.337-1.315-1.293-1.272-1.251-1.230-1.210-1.189-1.170-1.150-1.132-1.114-1.096-1.077-1.060-1.042-1.026-1.010-0.993-0.978-0.963-0.947-0.930-0.916-0.901-0.887-0.872-0.857-0.843-0.828-0.815-0.803-0.789-0.776-0.763-0.751-0.739-0.727-0.714-0.702-0.689-0.677-0.665-0.653-0.643-0.631-0.619-0.608-0.596-0.585-0.574-0.564-0.553-0.542-0.533-0.523-0.513-0.503-0.494-0.484-0.474-0.464-0.455-0.446-0.436-0.427-0.418-0.409-0.400-0.391-0.383-0.374-0.366-0.357-0.348-0.340-0.332-0.324-0.316-0.307-0.299-0.291-0.284-0.276-0.268-0.260-0.252-0.245-0.238-0.230-0.222-0.215-0.208-0.201-0.193-0.186-0.179-0.172-0.165-0.158-0.151-0.144-0.137-0.131-0.124-0.117-0.110-0.104-0.098-0.092-0.085-0.079-0.072-0.066-0.059-0.053-0.047-0.040-0.035-0.029-0.023-0.017-0.011-0.0060.0010.0070.0120.0180.0240.0300.0360.0410.0470.0520.0580.0630.0690.0750.0800.0850.0910.0960.1010.1070.1120.1180.1230.1280.1330.1380.1430.1490.1540.1580.1640.1690.1730.1790.1830.1880.1930.1980.2030.2070.2120.2170.2210.2260.2300.2350.2400.2440.2480.2530.2570.2620.2660.2710.2750.2790.2840.2880.2920.2970.3010.3050.3090.3130.3170.3220.3260.3300.3340.3380.3430.3470.3510.3550.3590.3630.3680.3720.3750.3800.3830.3880.3910.3950.3990.4030.4070.4110.4140.4180.4220.4260.4290.4330.4370.4400.4440.4480.4520.4550.4590.4630.4660.4690.4730.4770.4800.4840.4870.4910.4940.4980.5010.5050.5080.5120.5150.5180.5220.5250.5280.5320.5350.5380.5420.5450.5480.5510.5550.5580.5610.5650.5680.5710.574

-39.144-5.035-4.734-4.258-3.974-3.753-3.568-3.413-3.281-3.151-3.028-2.918-2.814-2.720-2.634-2.554-2.476-2.408-2.346-2.285-2.228-2.174-2.125-2.075-2.027-1.984-1.941-1.898-1.857-1.819-1.783-1.749-1.717-1.684-1.654-1.624-1.593-1.564-1.538-1.511-1.484-1.458-1.433-1.407-1.383-1.359-1.337-1.315-1.293-1.272-1.251-1.230-1.210-1.189-1.170-1.150-1.132-1.114-1.096-1.077-1.060-1.042-1.026-1.010-0.993-0.978-0.963-0.947-0.930-0.916-0.901-0.887-0.872-0.857-0.843-0.828-0.815-0.803-0.789-0.776-0.763-0.751-0.739-0.727-0.714-0.702-0.689-0.677-0.665-0.653-0.643-0.631-0.619-0.608-0.596-0.585-0.574-0.564-0.553-0.542-0.533-0.523-0.513-0.503-0.494-0.484-0.474-0.464-0.455-0.446-0.436-0.427-0.418-0.409-0.400-0.391-0.383-0.374-0.366-0.357-0.348-0.340-0.332-0.324-0.316-0.307-0.299-0.291-0.284-0.276-0.268-0.260-0.252-0.245-0.238-0.230-0.222-0.215-0.208-0.201-0.193-0.186-0.179-0.172-0.165-0.158-0.151-0.144-0.137-0.131-0.124-0.117-0.110-0.104-0.098-0.092-0.085-0.079-0.072-0.066-0.059-0.053-0.047-0.040-0.035-0.029-0.023-0.017-0.011-0.0060.0010.0070.0120.0180.0240.0300.0360.0410.0470.0520.0580.0630.0690.0750.0800.0850.0910.0960.1010.1070.1120.1180.1230.1280.1330.1380.1430.1490.1540.1580.1640.1690.1730.1790.1830.1880.1930.1980.2030.2070.2120.2170.2210.2260.2300.2350.2400.2440.2480.2530.2570.2620.2660.2710.2750.2790.2840.2880.2920.2970.3010.3050.3090.3130.3170.3220.3260.3300.3340.3380.3430.3470.3510.3550.3590.3630.3680.3720.3750.3800.3830.3880.3910.3950.3990.4030.4070.4110.4140.4180.4220.4260.4290.4330.4370.4400.4440.4480.4520.4550.4590.4630.4660.4690.4730.4770.4800.4840.4870.4910.4940.4980.5010.5050.5080.5120.5150.5180.5220.5250.5280.5320.5350.5380.5420.5450.5480.5510.5550.5580.5610.5650.5680.5710.574

25

30

35

40

45

50

55

60

65

70

75

POL CMC and Surface Tension Reading

0.15mL/hr-POL-01 0.15mL/hr-POL-01

Ln (Conc, mM)

Su

rfac

e T

ensi

on

, g

(m

N/m

)

% w/v

Constant at 31mN/m

CMC at 1mM or 0.055% w/v

STS CMC and Surface Tension Measurement

STS Foam Viscosity Properties

STS Foam Viscosity Properties

CFD Analysis (Liquid POL and blood)

Boundary Condition : 2.0m/s POL inlet, 0.01m/s Superficial Vein inlet and 0.02m/s Femoral Vein inlet at t = 10.000s

CFD Analysis (Liquid POL and blood)

Boundary Condition : 2.0m/s POL inlet at t = 10.00s

0 Pa for all outlets.

In-Vitro Experiment STS Foam (0.5mL STS + 2mL Air)

In-Vitro Experiment STS Foam (1+4)

In-Vitro Experiment STS Foam (1+4)

In-Vitro Experiment STS Foam (1+4)

All photos are 0.7s interval.

Future Direction

•Apply at least one more viscosity model for comparison.

•Incorporate syringe into the geometry where moving boundary will be applied to syringe for meaningful simulations’ results.

•Simulate when patient’s leg were lift up in an angle on the Sapherofemoral joint case emphasizing on sclerosant foam.