VADS
title: VADS tags: #FFICM #cardiac #mechanical_cardiac_support notebook: ð-FFICM type: anki
| Flashcard | type:cloze |
|---|---|
| An {{c1::L-VAD::What side VAD}} goes from the {{c2::left atrium}} to the {{c2::ascending aorta}} | |
| An {{c1::R-VAD::What side VAD}} goes from the {{c2::right atrium}} to a {{c2::pulmonary artery}} |
| Flashcard | type:basic |
|---|---|
| The main advantage of ECMO over a VAD is that | VADS require sternotomy and peripheral ECMO doesn't |
| The main advantage of a VAD over ECMO is that | You can go home with a VAD, they can be used for a longer time period |
Indications for VADS
Can be to support left ventricle (LVAD), right ventricle (RVAD) or both (BIVAD) 2
The LVAD goes from left atrium to ascending aorta, the RVAD from right atrium to pulmonary artery. Requires sternotomy. 2
BIVAD versus ECMO: ECMO is less invasive (no sternotomy). But ECMO is more resource intense and needs more attention to maintain it. So ECMO better for short term, LVAD for longer term. 2
Bridge to Heart Transplantation Average waiting time to heart transplant is greater than 6 months, so a VAD can support you until then. Patients can be discharged home on a VAD. 2
Destination Therapy (aiming to go on and stay on) Is done in places outside UK but not in UK. 2 Here you normally just need LV support, and RV failure will get better with an LVAD as it removes the pulmonary hypertension, but sometimes you need proper BIVAD support. BIVAD patients have worse outcomes as there's more complexity in machine use, and RVADs aren't designed for longer term use. 2
VAD Complications
Bleeding - Commonly coagulopathic. More likely if prolonged cardiopulmonary bypass, hypothermia, blood transfusions. The device can use consume platelets. Puts patients at risk of intracranial haemorrhage 2
Tamponade - Warning signs are decreasing flows, increasing CVP, decreasing MAP. Needs immediate surgery 2
RV Failure 2
GI/Hepatic Dysfunction - First gen VADS put a lot or pressure on stomach and intestines. 2
| Flashcard | type:basic |
|---|---|
| In terms of heart function, what was the main complication of earlier ventricular assist devices? | Right Heart Failure, with GI/Hepatic Congestion |
| In terms of bleeding, what was the main complication of ventricular assist devices? | Consumptive coagulopathy |
| In terms of VADS, what are the two main concerning ways they can worsen shock? | Cardiac Tamponade, and RV Failure (in LVADs) |
TandemHeart
| Flashcard | type:basic |
|---|---|
| What type of pump is a TandemHeart VAD? | A "centrifugal" pump |
| What type of pump is an Impella VAD? | An archimedes screw |
This is a percutaneous "centrifugal pump" that can give circulatory support up to 4L/min. 1 Takes oxygenated blood from left atrium (21 french catheter - placed through trans-septal puncture), reinjected into aorta or iliac arteries (15-17 french catheter) 1
That initial catheter goes in through femoral vein, up to right atrium, punched through the septum into the left atrium. So more invasive and difficult to place than IABP. 1
Evidence around it:
Thiele - 2005 - RCT: Tandemheart vs no tandemheart in cardiogenic shock. Improvements in cardiac power but no change in 30 day mortality. 1
Kar - 2011 - Case Reports: 80 patients with cardiogenic shock following ACS. Half following CPR. 6 month mortality was 45%. Complications included death from wire perforating left atrium (1/80), GI tract bleeding (20%), Stroke (7%), Limb Ischaemia (3.5%) 1
Impella
This is a continues "non-pulsatile, axial flow Archimedes-screw pump". This is inserted and takes blood from left ventricle into ascending aorta. 1
Advantages: does not require a stable rhythm like IABP would. 1
Complications include: device migration, device failure from thrombosis (clotted up), haemolysis, bleeding, limp ischaemia, tamponade, valve injury, stroke, arrythmias. 1
Comes in 3 forms: 2.5 - Up to 2.5L/min - insert percutaneous (12-14 fr sheath) CP - 3.7L/min - insert percutaneous (12-14 fr sheath) 5 - 5L/min - insert surgically (cutdown of femoral artery before insertion of 22 fr sheath) ( + Impella RP - for right ventricular support - 4L min) 1
Evidence around it:
ISAR-SHOCK: RCT - 26 patients, Impella 2.5 vs IABP. No differences in mortality, no differences in cardiac index, serum lactate. More complications in impella (haemolysis/transfusion) 1
IMPRESS, 2017: RCT - 48 patients, Impella CP vs IABP. Similar 30 day mortality in impella vs IABP. More vleeding in impella. 1
Metaanalysis - 148 patients. Impella and Tandemheart have not been associated with increased survival in cardiogenic shock. 1
RV Failure: RECOVER RIGHT = cohort study - 30 patients. Potentially improvement in survival rates compared to other cardiogenic shock cohorts. 1
History of VADS
1st Gen
These are pulsatile at physiological rates. 2
The pulsation could be pneumatic/hydraulic/pusher plate. These will make a pump sound. 2
They work, but significant morbidity from surgical dissection, a big pump, and a large lead needed to vent air. They won't generally last longer than 2 years. 2
2nd Gen
These are non pulsatile, so pumps can be smaller and don't need vents/ 2
Second gen are rotary pumps with axial flow, with contact bearings. "Essentially a propeller in a pipe". The rotor is linked to external magnet. 2
3rd Gen
These are rotary pumps with non-contact bearings. These have centrifugal blood flow. They use an "impellar" rotation and external magnets. 2
They should be more durable than second gen as no contact bearings. They can have higher blood flow so you should have less risk of thrombus. 2
[[Acute Heart Failure]]
[[IABP]]
[Acute Heart Failure]: