Windkessel effect

Windkessel effect

എന്താണ് വിൻഡ്‌കെസൽ എഫ്ഫക്റ്റ്?

The term ‘Windkessel effect’ is used in the setting of large elastic arteries like aorta. The original term ‘Windkessel’ means ‘air chamber’ in German language. It was an air chamber used in fire engines in the 18th century, to maintain continuous delivery of water for fire fighting. In the case of aorta, the aortic elasticity causes expansion and temporary storage of blood in systole so that more blood enters the aorta than what leaves it in systole. This buffer stock of blood is released during diastole, to maintain organ perfusion. The Windkessel effect makes aorta function as a ‘second pump’ in diastole. This diastolic flow is quite important in the case of coronary perfusion as most of the coronary perfusion is diastolic. As the elasticity decreases with aging, this buffer effect is reduced leading to an increase in arterial pulse pressure and systolic pressure.

Windkessel effect ensures a smooth blood flow after passing through the elastic aorta though ejection from the left ventricle is intermittent [1]. The effect also helps to maintain a normal cardiac output and intravascular volume in the setting of uncomplicated essential hypertension [2]. This gets altered when the arterial stiffness increases later on.

Windkessel effect may a play a role in larger internal carotid artery aneurysms which act as a capacitance chamber. Slow arrival of contrast distal to the aneurysm has been noted [3]. It has been postulated that loss of this effect after treatment of large aneurysms may place the distal cerebral circulation at risk of hemorrhage.

References

1. Mei CC, Zhang J, Jing HX. Fluid mechanics of Windkessel effect. Med Biol Eng Comput. 2018 Aug;56(8):1357-1366.
2. Safar ME. Arterial stiffness as a risk factor for clinical hypertension. Nat Rev Cardiol. 2018 Feb;15(2):97-105.
3. Hussein AE, Esfahani DR, Linninger A, Charbel FT, Hsu CY, Charbel FT, Alaraj A. Aneurysm size and the Windkessel effect: An analysis of contrast intensity in digital subtraction angiography. Interv Neuroradiol. 2017 Aug;23(4):357-361.