Intra-aortic balloon pumping:
 

Beneficial effects
reduces cardiac work by decreasing afterload
increases coronary blood flow
Basic mechanism
placed in the thoracic aorta
balloon inflated during diastole, thus increasing aortic pressure during diastole and increasing coronary blood flow
balloon deflated prior to and during early left ventricular ejection thus reducing aortic pressure and thus afterload
Indications
Indicated in the following conditions if further medical treatment judged likely to be ineffective:
     pump failure imminent or frank
acute mitral regurgitation
unstable angina
Also useful in
high risk patients undergoing PTCA
ventricular arrhythmias refractory to conventional treatment
patients at high risk of cardiac decompensation during non-cardiac surgery
Contraindications
aortic insufficiency
aortic dissection
(prosthetic graft in thoracic aorta)
severe aortoiliac disease
Complications
    During insertion
failure to advance catheter beyond iliofemoral system because of atherosclerotic disease (most common complication)
aortic dissection and arterial perforation
    During use
limb ischaemia most common. Sufficiently severe to require removal of balloon in 11-27%
sepsis. Relatively unusual but associated with high mortality. Positive blood cultures require prompt removal and culture of IAB and treatment with antibiotics
thrombocytopaenia
embolization of platelet aggregates from surface of balloon and cholesterol emboli
balloon rupture leading to embolization of helium (2-4%). May be heralded by high balloon inflation pressures. Blood in connecting tubing is hallmark of rupture and requires immediate cessation of counterpulsation, placement of patient head down and IAB removal. Antibiotic cover should be broadened as the gas chamber of the balloon is not sterile.
small perforation in balloon membrane may allow small leak of blood into balloon lumen. Dry helium dessicates the collected blood which then forms a hard pellet which may prevent removal of balloon except by surgical aortotomy.
   During or following removal
haematoma 
false aneurysm 
AV fistula