Table 4. INTERMACS patient profiles and mechanical support timing^170,171.

Level	Definition		Description	Time to MCS
1	“Crash and burn”	Critical cardiogenic shock	Patients with life-threatening hypotension despite rapidly escalating inotropic support, critical organ hypoperfusion, often confirmed by worsening acidosis and/or lactate levels.	Within hours
2	“Sliding on inotropes”	Progressive decline	Patients with declining function despite intravenous inotropic support may be manifested by worsening renal function, nutritional depletion, and an inability to restore volume balance.	Within a few days
3	“Dependent stability”	Stable but inotrope dependent	Patients with stable blood pressure, organ function, nutrition, and symptoms on continuous intravenous inotropic support (or a temporary circulatory support device or both), but demonstrating repeated failure to wean from support due to recurrent symptomatic hypotension or renal dysfunction.	Within a few weeks
4	“Frequent flyer”	Resting symptoms	Patients can be stabilized close to normal volume status but experience daily symptoms of congestion at rest or during activities of daily living (ADL). Doses of diuretics generally fluctuate at very high levels. More intensive management and surveillance strategies should be considered, which may in some cases reveal poor compliance that would compromise outcomes with any therapy.	Within weeks to months
5	“Housebound”	Exertion intolerant	Comfortable at rest and with ADL but unable to engage in any other activity, living predominantly within the house. Patients are comfortable at rest without congestive symptoms but may have underlying refractory elevated volume status, often with renal dysfunction.	Variable
6	“Walking wounded”	Exertion limited	Patients without evidence of fluid overload are comfortable at rest, and with ADL and minor activities outside the home but fatigue after the first few minutes of any meaningful activity.	Variable
7	“Placeholder”	Advanced NYHA functional class III	Includes patients who are without current or recent episodes of unstable fluid balance, living comfortably with meaningful activity limited to mild physical exertion.	Not a candidate for MCS

INTERMACS, Interagency registry for mechanically assisted circulatory support; MCS, mechanical circulatory support; NYHA, New York Heart Association.