VAD Basics
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Direct answer
Continuous-flow rotary pumps have entirely displaced the older pulsatile devices: a modern ventricular assist device (VAD — an LVAD when it supports the left ventricle) draws blood from the ventricular apex and returns it to the ascending aorta, unloading the ventricle while the patient lives with a continuous, largely pulseless circulation. Four strategies frame every discussion — bridge to transplant, bridge to candidacy (reversing pulmonary hypertension and end-organ dysfunction), bridge to recovery (myocarditis above all), and destination therapy in transplant-ineligible patients. The fully magnetically levitated HeartMate 3 is the current benchmark, its MOMENTUM 3 trial showing far better freedom from pump thrombosis and reoperation.
What you must remember
- Nomenclature: LVAD, RVAD and BiVAD by chamber supported; the inflow cannula sits in the ventricular apex, the outflow graft joins the ascending aorta, and the driveline exits the abdominal wall to batteries or mains.
- INTERMACS profiles time the implant, from profile 1 ("crash and burn" — cardiogenic shock) through profile 3 (inotrope-dependent); durable implants fare best at profiles 3–4, not in florid shock.
- REMATCH (2001) established destination therapy: the pulsatile HeartMate VE roughly doubled one-year survival versus optimal medical therapy in transplant-ineligible patients — the trial that created the field.
- MOMENTUM 3 established the current standard: the magnetically levitated HeartMate 3 beat the HeartMate II for survival free of disabling stroke and reoperation, with pump thrombosis reduced to about 1%.
- The HeartWare HVAD was withdrawn worldwide in 2021 after analyses suggested excess neurological events and mortality — worth knowing when examiners ask which devices exist.
- Complications to list unprompted: stroke (haemorrhagic at least as often as ischaemic), driveline infection, pump thrombosis (rising lactate dehydrogenase, haemolysis, dark urine), right ventricular failure after implant, de novo aortic regurgitation, and gastrointestinal bleeding.
- Gastrointestinal bleeding arises from shear-induced acquired von Willebrand disease — the classic mechanism question.
- Management basics: warfarin with INR near 2–3 plus antiplatelet therapy; blood pressure assessed by Doppler opening pressure since there is no true pulse; speed balanced against septal position and aortic valve opening.
Choosing the support strategy
Two patients illustrate how the strategy, not the device, comes first. A 38-year-old with fulminant myocarditis in profound shock has a recoverable ventricle: the aim is bridge to recovery — temporary support (extracorporeal membrane oxygenation or a short-term centrifugal pump) with aggressive heart failure therapy and serial reassessment, weaned when ejection fraction returns; a durable implant would be a mistake. A 46-year-old with six years of dilated cardiomyopathy, pulmonary vascular resistance of 6 Wood units and listing deferred for that reason is the bridge-to-candidacy patient: an LVAD unloads the left side, pulmonary pressures fall over months, and transplantation becomes possible — a sequence worth articulating, since device access determines who can run it. A 66-year-old with ischaemic failure, prior bypass grafting and contraindication by age and renal function is the destination-therapy patient, committed to a device for life. The wrong strategy wastes the right device — precisely what examiners build stems to test.
The no-pulse patient and other traps
Examination questions flow naturally: no palpable pulse, a continuous pump hum, blood pressure by Doppler opening pressure, and a patient whose collapse may be anything from a driveline fault to pump thrombosis. Rising lactate dehydrogenase and haemoglobinuria in a supported patient mean pump thrombosis until proven otherwise, with management escalating from heparin and speed changes to exchange or transplant. De novo aortic regurgitation develops as the native valve stays shut — a leak that recirculates through the pump. And the simplest trap: forgetting that LVAD patients remain heart failure patients — right ventricular failure after implant predicts early death, which is why it dominates pre-implant assessment.
Frequently asked questions
What are the four support strategies for ventricular assist devices?
Bridge to transplant, bridge to candidacy, bridge to recovery and destination therapy. Strategy is chosen before device, because it determines durability, urgency and the exit plan.
Which device is the current benchmark and on what evidence?
The HeartMate 3, a fully magnetically levitated continuous-flow pump. MOMENTUM 3 showed superiority over the HeartMate II in survival free of disabling stroke and reoperation, with pump thrombosis of about 1%.
Why does an LVAD patient have no palpable pulse?
Continuous-flow pumps generate non-pulsatile circulation, so arterial pressure is a mean value measured by Doppler opening technique.
How is pump thrombosis detected and treated?
By rising lactate dehydrogenase, free haemoglobin and haemoglobinuria with signs of low flow or heart failure. Treatment escalates from intensified anticoagulation and thrombolysis to pump exchange or transplantation.
What was the REMATCH trial?
A 2001 randomised trial of pulsatile LVAD support versus optimal medical therapy in transplant-ineligible heart failure, showing roughly a doubling of one-year survival with the device — the study that legitimised destination therapy.
What makes right ventricular failure the central pre-implant concern?
Unloading the left ventricle shifts venous return to the right heart; a weak right ventricle fails to fill the pump, causing congestion and low output. Severe irreversible right failure argues against an isolated LVAD or for biventricular support.