Function of the aorta
The heart pumps blood into the aorta in pulses. This pulsatile blood flow must be converted into a continuous flow to supply the body. While the aorta stretches well, especially near the heart, due to the high proportion of elastic fibres in the fine tissue when the blood is expelled from the heart (systole), it stores half of the expelled volume quasi temporarily due to the stretching.
Subsequently (in diastole, i.e. the slackening of the heart muscle) the vessel expands and the other half of the ejection fraction is replenished. In this way the blood flow is even and the organs are protected from damage by the continuous supply. This function is also known as the windkessel function. Certain diseases of the vessels can cause the elasticity to decrease and organs to be damaged by high blood pressure or reduced blood flow.
Diagnostics for diseases of the aorta
The following options are available for examining the aorta:
- Ultrasound / Sonography
- TEE (transesophageal ultrasound = ultrasound via the oesophagus)
- X-ray images
- Computer tomography
- Angiography / Heart catheter
Waves are emitted through a transducer, which are reflected differently. The return of the waves is registered. Depending on the strength of the reflection, this can be displayed on a screen in a darkened room and the images can be printed out.
Since the heart and parts of the aorta are in close anatomical relation to the oesophagus, these organs can be viewed by means of this transesophageal echocardiography. Diseases like: can be diagnosed in this way. – Thromboses
- Aneurysms (vascular wall bulges)
- Initma detachments (dissection) or
- Rupture of the aorta (ruptures)
An X-ray of the entire thorax can provide an overview of the size, position and course of the aorta.
An extended form of X-ray imaging is computed tomography (CT). Here, a large number of X-ray images are produced in a tube, which are then added to a three-dimensional image under computer control. Using X-rays and a contrast medium, blood vessels can be displayed and assessed in an angiography.
In a cardiac catheter, a probe is pushed through an artery, usually the femoral artery, against the direction of flow back to the heart and the blood flow, heart function and aorta are tested by administering a contrast medium. Depending on the problem, magnetic resonance imaging (MRI) can also be used. In this case, the vessels can also be depicted without using a contrast medium. This is helpful in cases of known contrast medium allergies. Again, sectional images are taken in a tube, but without using X-rays.