Question 13

Compare and contrast the advantages and limitations of the intra-aortic balloon pump (IABP) and ventricular assist devices (VAD). (You may tabulate your answer).

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College Answer

	IABP	VAD
	Can be inserted percutaneously in ICU or CCU	While percutaneous insertion is possible, frequently require anaesthesia and a surgeon for insertion and removal.
Indications	Used post cardiac surgery / cardiogenic shock following an infarct	Frequently used in post cardiac surgical patients. Used as a bridge to transplantation.
Logistics	Intensivists more familiar with IABP Can be used during transport	Less familiar with VAD, greater degree of complexity, more difficult to use during transport
Anticoagulation	Usually no need for anticoagulation	Need for anticoagulation
	Not effective in the setting of CI < 1.2 and tachyarrhythmias	Greater control on overall cardiac output as well as Rt and Lt ventricular output
Complications	Lower limb ischemia, hematoma, aortic trauma are complications	Bleeding, infection, hemolysis, device failure

Discussion

I love it when they invite you to tabulate your answer.

Among the things worth mentioning is the horrific rate of infectious complications with the VAD (up to 50% of patients have an LVAD-associated infection) and the fact that its not merely anticoagulation, but insane anticoagulation that is required (APTT target is 150-200).

It is difficult to compare the two therapies, of course. An IABP is a supportive treatment to assist the recovering cardiac patient. The VAD is essentially a mechanical heart. There are reports of people who were awake, and asystolic, with a VAD in situ.

Beyond the tabulated answer offered here, the following chapters may be meaningful:

A slightly expanded answer, with more detail, is also offered:

LV Assist Device vs Intra-Aortic Balloon Counterpulsation
	IABP	VAD
Indications	No choice but pump Failure to come off bypass Severe aortic stenosis Mitral regurgitation Ventricular septal defect Probably harmless, but probably not useful High-risk PCI patients (pre-op) - IABP-SHOCK II High-risk pre-CABG patients (low LVEF) Cardiogenic shock while waiting for PCI (i.e. bridge to definitive intervention) Pulmonary oedema in spite of maximal medical management Totally experimental Takotsubo cardiomyopathy Neurogenic stress cardiomyopathy of subarachnoid haemorrhage Known to be pointl	Firm indications: Failure to come off bypass Cardiogenic shock Cardiac arrest Fulminant myocarditis Potential indications: High risk CABG patients (pre-op) High-risk PCI patients (pre-op)
Contraindications	Absolute contraindications Aortic regurgitation Aortic aneurysm Aortic dissection Severe sepsis Uncontrolled coagulopathy Relative contraindications Atherosclerosis and arterial tortuosity Left ventricular outflow tract obstruction Contraindications to anticoagulation	Aortic regurgitation Aortic aneurysm Aortic dissection Severe sepsis Uncontrolled coagulopathy Left heart thrombus
Advantages	Bedside insertion Familiarity among ICU staff Less invasive Flow is pulsatile; organ perfusion benefits	Able to compensate for all cardiac function (i.e. useful in the setting of asystole) May remain in situ for longer than the IABP Contrary to the college answer above ("more difficult to use during transport") most patients with VADs can be mobilised normally (Mohiyaddin, 2018)
Disadvantages	Useless if the cardiac index is less than 1.5 Insertion may be frustrated by poor peripheral arterial anatomy	Non-pulsatile flow; poor organ perfusion Requires sternotomy for insertion (for most except the TandemHeart device, which can be inserted percutaneously) Unfamiliarity among ICU staff
Anticoagulation	May not require anticoagulation	Requires mandatory anticoagulation
Complications	Common complications Mild limb ischaemia - 2.9% Balloon leak - 1.0% Major limb ischaemia - 0.9% Haemorrhage - 0.8% Leg amputation due to ischaemia - 0.1% Rare complications Atheromatous cholesterol emboli Aortic or arterial dissection Cerebrovascular accident Thrombocytopenia Haemolysis Helium embolism	Infection is the major cause of morbidity; something like 50% of the implanted devices get infected. The LV gets (understandably) irritated by the presence of an LVAD, and in 25% of patients ventricular arrhythmias develop Thrombi form on the walls of the device in spite of anticoagulation, and 10-16% of people have thrombotic complications. Some degree of haemolysis and thrombocytopenia occur in everybody

Even more broadly, the chapter on mechanical haemodynamic support strategies contains a comparison of several other mechanical methods of increasing cardiac output.

References

To the tabulated answer presented here, I would add a reference or two to aid those (like me) who have never even seen a VAD.

UpToDate has a nice chapter on VADs.

My own barebones summary of the VAD is available here. IABP receives a slightly more elaborate treatment here.

EMCrit brandishes the expertise of somebody who works with these things, and I take that seriously.

Additionally, there is an insanely colourful brochure which has device-specific recommendations.

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