Intra-aortic balloon pumps (IABP) are used in the intensive care setting to provide haemodynamic assistance to patients in cardiogenic shock.
Function and physiology
The device is comprised of a catheter introduced via the femoral artery, which extends retrogradely to the proximal descending thoracic aorta. A balloon is located at the end of the catheter, spanning 26-28 cm in length, which is rapidly inflated at the beginning of diastole and rapidly deflated at the end of diastole. The balloon is inflated with helium.
As the balloon forcibly inflates it displaces blood both forwards and backwards, known as diastolic augmentation. As such it provides not only additional forward momentum to the blood in the distal descending aorta but more importantly increases perfusion to the vessels arising from the arch of the aorta, most importantly the coronary arteries which are perfused primarily during diastole 1-2.
This has a dual effect: it firstly decreases left ventricular after load through a vacuum effect, decreasing myocardial oxygen requirements, and secondly increases myocardial perfusion (during diastole) 1-2.
Some catheters are radiolucent except for a distal radio-opaque marker. If the film is obtained during diastole then the balloon can be seen as a radiolucent oblong aligned with the thoracic aorta 1.
The balloon should be located in the proximal descending aorta, just below the origin of the left subclavian artery. This ideally results in the balloon terminating just above the splanchnic vessels 3.
Complications may occur in around 30% of cases 4 can be divided into those relating to balloon function and those related to balloon positioning.
- mal-positioning: considered commonest complication
- aortic or large vessel arterial dissection during insertion
- obstruction of the left subclavian artery or renal arteries
- platelet and red blood cell destruction
- aortic dissection (1% 4) or large vessel arterial dissection during insertion
- distal embolisation (this can be to the brain if positioning is too proximal)
Additionally, the catheter is quite large and the resultant common femoral artery defect can be difficult to close with routine compression. False aneurysm formation may thus occur.
- acute aortic syndrome
- thoracic aortic aneurysm
- abdominal aortic aneurysm
- endovascular aneurysm repair (EVAR)
- reporting tips for aortic aneurysms
- aortic coarctation
- aortic pseudocoarctation
- cervical aortic arch
- interrupted aortic arch
- transposition of the great arteries
- variant anatomy of the aortic arch
- traumatic aortic injuries
- 1. Chest Radiology. Lippincott Williams & Wilkins. (2012) ISBN:146980204X. Read it at Google Books - Find it at Amazon
- 2. Clinical Anesthesia. Lippincott Williams & Wilkins. (2012) ISBN:1451147953. Read it at Google Books - Find it at Amazon
- 3. Mebazaa A, Gheorghiade M. Acute Heart Failure. Springer. (2008) ISBN:1846287820. Read it at Google Books - Find it at Amazon
- 4. Ginat D, Massey HT, Bhatt S, Dogra VS. Imaging of mechanical cardiac assist devices. Journal of clinical imaging science. 1: 21. doi:10.4103/2156-7514.80373 - Pubmed