1. Percutaneous RVAD support following LVAD implant
Joseph Hughes
Clinical Perfusionist

2. Heart Failure - LVAD therapy
LVAD (Heartmate / Heartware) – Bridge to Transplant
Offloads left ventricle (LV)
↑ cardiac output
Improves end organ function
Improves exercise tolerance and quality of life
Pathophysiology often effects both ventricles
Right Ventricle Failure following LVAD implant % (Argiriou, 2014).
RVF following LVAD → increased mortality,
increased length of stay,
lower bridge-to-transplant rate.(Rich, 2012).
Strong predictor of 1 year mortality (Algothani,2016)
Rich, Jonathan D. (2012) Right Ventricular Failure in Patients with Left Ventricular Assist Devices. Cardiology Clinics , Volume 30 , Issue 2 , 291 – 302
Alghothani, Mohamad et al. (2016) Severity of Right Heart Failure Post LVAD Implantation Predicts 1 Year Mortality, Journal of Cardiac Failure , Volume 22 , Issue 8 , S117 - S118
Argiriou, Mihalis et al. “Right Heart Failure Post Left Ventricular Assist Device Implantation.” Journal of Thoracic Disease 6.Suppl 1 (2014): S52–S59. PMC. Web. 19 Sept
Implantable mechanical circulatory support devices have become an important and viable bridge-to-transplant therapy in recent years.
Devices such as Heartware and Heartmate allow offloading of the left ventricle (LV) and increase cardiac output, improving end organ function, exercise tolerance and quality of life whilst awaiting heart transplantation.
However, the pathology that effects the LV during advanced heart failure often effects both ventricles, with a reported range of right ventricle failure following LVAD implant between 10-40% of patients.
Right ventricle failure (RVF) following LVAD implant is a key risk factor and predictor of mortality in LVAD patients, with survivors continuing to experience morbidity related to right ventricular failure which effects their chances of bridging to transplant at a later date.
So as we can see, recovery of the right ventricle is of paramount importance both the function of the implanted LVAD and the long term recovery and quality of life for the patient.

3. Right Ventricle RV highly sensitive to changes in afterload
Strong interdependence with LV function,
20-40% of function due to LV contraction,
Interventricular septum (IVS) (systolic)
Pericardium (diastolic).
LVAD impacts RV function
IVS shifts position
Shape and size of left heart chambers altered
Change preload/afterload
Changes can benefit or hinder RV function
The right ventricle is highly adaptable to changes in preload, however conversely it is highly sensitive to changes in afterload, which can effect function and long term recovery of the right ventricle.
The contraction of the intraventricular septum also contributes significantly to the systolic function of the right ventricle,
Changes to the position of the intraventricular septum caused by LVAD offloading the LV, along with changes to the volume and pressures in the left sided chambers, can cause both improvement and detriment to RV function.

4. RV failure in LVAD patients
LVAD effects on RV function
Improvement Decompresses LV,
↓ LVEDP/EDV
RV afterload ↓
Deterioration Leftward shift of IVS
diminished septal contribution to RV function
TV leaflet tethering
↑ RV volume and ↓ RV function
↑ TR
Fluid resuscitation to maintain LVAD flow →
RV dilatation
Acute increase in cardiac output from LVAD → Increase in venous return,
increasing RV preload and RVF
Right ventricle function improvements following LVAD implant are due to the offloading and decompression of the left ventricle on initiation of LVAD therapy. This causes a drop in the end diastolic volumes and pressures in the left sided heart chambers, resulting in a decrease in PA pressures and RV afterload. This reduction in afterload should normally allow the right ventricle to recover and sufficiently provide the LV with sufficient filling.
However the initiation of LVAD therapy provides conditions that are detrimental to the function of the right ventricle.
These are primarily concerned with the contribution of the intraventricular septum, which tends toward a leftward shift due to decompression of the LV. This reduces septal contribution to RV contraction and causes tricuspid valve leaflet tethering. The result of this increases RV volume, causing further tricuspid regurgitation and decreased RV function.
The failing right ventricle in the peri operative setting may provide inadequate filling to the left ventricle, resulting in inadequate LVAD flows and decreased cardiac output. The common reaction to this is fluid resuscitation, which further contributes to RV dilatation, increased tricuspid regurgitation and further right heart failure.
Another detrimental effect of the LVAD on the RV can be caused by an acute increase in cardiac output provided by the LVAD flows, which increases venous return to the already compromised RV and futher contributes to RV failure.

5. Current RVF treatment Inotropic support Inhaled NO Volume management.
Arrhythmia management.
Protective ventilation.
Mechanical support??
1st 49 of 70 LVAD patients had no RV support,(19/10/16)
1 pt Centrimag RVAD.
2 pts Protek RVAD.
Current treatment for RV failure firstly centres around the use of a combination of inotropes and ventilatory management, with the aim of decreasing afterload through the reduction of pulmonary vascular resistance, and increasing contractility of the heart.
Volume management through CVVH aims to decrease preload and RV dilatation to promote RV recovery.
However if these therapies are unable to provide adequate RV support and are unable to be weaned effectively, the decision may be made to escalate to mechanical right sided support, although out of the 70 patients who have received an LVAD to date at the QE, only 3 have required escalation to mechanical RVAD support, one in the form of centrimag and two receiving percutaneous RVAD support.

6. CentriMag mechanical support
Direct surgical cannulation
34 fr drainage catheter, 24 fr return cannula. (RA→PA)
Allows full offloading of RV, with flows up to 9.9 L/min
Cannulae tunnelled through chest cavity.
Re-sternotomy required.
Patient not ambulatory.
Risk of bleeding, infection.
Centrimag RVAD support requires the direct cannulation of the right atrium and pulmonary artery, with the cannulae commonly tunnelled through the chest cavity and connected to the centrimag pump.
Although the centrimag RVAD provides almost complete offloading of the right ventricle, and is extremely reliable technology, it also requires resternotomy not only for insertion, but also for decannulation.
This is associated with the common complications of infection, bleeding and trauma to the heart chambers and vessels.

7. TandemHeart Protek Duo Cannula
29fr dual lumen cannula
Right internal jugular vein (RIJ) insertion
Drainage holes sit in RA
Return tip in PA
Oxygenator / Tandemheart pump optional.
Flows up to 3.9 L/min for RV support
An alternative to direct cannulation has been made possible with the introduction of the TandemHeart Protek Duo cannula, which uses dual lumen technology to drain and return blood through the same cannula.
The 29fr cannula is inserted through the Right internal jugular vein and passes through the tricuspid and pulmonic valves. Drainage holes sit in the right atrium and the return tip of the cannula sits in the pulmonary artery, resulting in offloading of the right ventricle.
At the QE we use the centrimag pump in conjunction with the protek cannula for percutaneous RVAD support, although the tandemheart pump is also available to be used in combination with the cannula. There is also the option to combine an oxygenator in the circuit if lung function has become compromised after LVAD implant.
The maximum cannula flow recommended by the manufacturer is 3.9 l/min, although we have comfortably achieved just over 4 l/min

8. ↓ Microvascular resistance
Haemodynamic effects RA PA
↓ EDP,
↓ EDV
↓ Wall Tension
↓ Microvascular resistance
↓ Mechanical Work
↓ Oxygen demand
↑Pulmonary blood flow
↑ LV Filling
↑ LVAD flow
↑ Coronary blood flow
↑ Cardiac output
The drainage and return portions of the cannula combine to aid RV recovery and increase end organ perfusion, with the aim of therapy to allow weaning of ventilatory and inotropic support and eventual RV recovery.
Drainage of the right atrium reduces end diastolic volumes and pressures in the right ventricle, which aids RV recovery through the reduction of wall stress distension and mechanical work.
Increased return of blood to the PA results in increased pulmonary blood flow, increases LVAD flow through raised LV preload, and results in improved cardiac output and coronary blood flow.
This increase in coronary blood flow further aids RV recovery and function, which may allow further weaning of the RVAD.
RV Recovery
↑ End organ perfusion

9. Implant procedure Flouroscopic or TOE guided
Seldinger insertion technique
stiff guidewire
PAFBC catheter exchange
Protek Duo cannula railroading
CentriMag pump,
Anticoagulation as per VAD protocol.
Weaning – reduction of flows under TOE and assessment of clinical parameters.
Aggarwal, V., Einhorn, B. N. and Cohen, H. A. (2016), Current status of percutaneous right ventricular assist devices: First-in-man use of a novel dual lumen cannula. Cathet. Cardiovasc. Intervent., 88: 390–396
Insertion is achieved through seldinger technique, with the cannula being exchanged over a stiff guidewire inserted with flouroscopic guidance. A pulmonary artery flotation balloon catheter may aid insertion but is not always required.
After insertion VAD is initiated and anticoagulation maintained as per institution VAD protocol.
If improvement of clinical parameters is achieved, along with weaning of inotropic and ventilatory support, further weaning of VAD flows is attempted using TOE guidance to assess right ventricle function and recovery.

10. Protek Duo at the QE Patient 1 Patient 2 44 years old Male.
Idiopathic DCM.
Severe LV dysfunction (EF 19%) and dilatation.
IABP therapy.
Heartmate III implanted.
Extubated POD 1, requiring large dose inotropes, inhaled NO, vasopressors.
Ventricular arrhythmias and progressive RV failure.
Protek Duo inserted POD 4, inotrope support weaned.
Protek weaned after 6 days therapy.
Discharged home on POD 39 with Heartmate III LVAD in situ.
59 years old Male.
Severe LV dysfunction due to ischemic heart disease
Severe pulmonary hypertension, renal impairment, AF.
Workup for TX - admitted acutely, decompensated heart failure, low C.O. state
Heartmate III LVAD implanted via left thoracotomy.
Protek Duo inserted POD 2 -inability to wean inotropes and vasoconstrictors
RVAD removed after 13 days therapy.
Discharged home on POD 30 with Heartmate III LVAD in situ.
Here is a brief summary of the two patients who have received percutaneous RVAD therapy at the QE.
Patient 1 presented with idiopathic dilated cardiomyopathy with severe LV dysfunction and ejection fraction of 19%. After a brief period of IABP therapy, the decision was made to implant a Heartmate III for bridge to transplant.
The patient was extubated post operative day 1 but was heavily reliant on increasing inotropes and Nitric oxide due to progressive RV failure.
Percutaneous RVAD was initiated POD 4 which allowed weaning of pharmacological therapies.
After RV assesment, the RVAD was weaned POD 6 and the patient continued his recovery to discharge on POD 39.
Patient 2 was a slightly older male who was undergoing workup for transplantation for ischemic heart failure following previous CABG.
He however presented acutely in decompensated heart failure in low cardiac output state and the decision was made to implant Heartmate III LVAD to bridge to recovery and transplant.
After implantation there was no progress being made to wean his inotropes and vasoconstrictors, so percutaneous RVAD support was started to aid this weaning and recovery of the RV.
After 13 days therapy and succesful weaning of support, the Protek was weaned and removed, with the patient recovering to discharge on POD 30.

11. Advantages over current therapy
Percutaneous insertion
Less invasive
Reduced risk of infection
Less bleeding
Greater mobility – If used in conjunction with Tandemheart centrifugal pump.
The advantages of the percutaneous RVAD support are mainly related to absence of complications that are related to direct cannulation RVAD that were discussed earlier.
A single puncture site and non requirement for resternotomy reduce risk of infection and bleeding which promote patients recovery and may improve outcome.
The patient may be ambulatory if combined with the tandemheart pump, although this may not be appropriate in the setting of LVAD patients who are unlikely to be fully ambulatory in the immediate post op period when RVAD therapy is required.

12. Risks and disadvantages
Insertion injury
Trauma associated with PAFBC – Bleeding, vein injury, arrhythmia, PA rupture, cardiac tamponade.
Limited offloading of RV – can achieve ≈ 4 L/min (31fr cannula due for release?)
Cost - £ VAT for Protek (+ £ VAT Centrimag)
= £ VAT vs £4000 for Centrimag pump + cannulae.
In setting of LVAD (£80,000 pump) is this extra cost significantly prohibitive vs potential savings benefit?
As well as the usual risks associated with percuataneous insertion of a large cannula in the jugular vein, the protek cannula is fairly limited in its offloading ability, which is mainly due to constrictions imposed by the small return lumen in the PA.
For flows above 4 l/min there may be some concern about shear stresses and haemolysis at the return tip, so there is a larger 31fr cannula due to be released which will go some way to alleviating these problems and allowing higher flows and more offloading of the RV.
Cost is also a major implication, with the protek and centrimag combination costing nearly double the normal combination of direct cannulae and centrimag, although is could be postulated that savings are potentially made in reduction of infection, blood products and length of stay, although more data would be needed to prove this benefit. Is this cost also relevent in the setting of an operation where the LVAD costs 80,000 alone?

13. Alternative mechanical RV support
Impella RP
Catheter inserted in femoral vein, sits across TV and PV.
Pump inlet in RA, outlet at tip in PA.
Capable of flows around 4 L/min.
Licensed up to 14 days support.
Peripheral V-A ECMO
Decompression and support of RV for recovery + systemic support.
Implanted LVAD output effected due to drainage from ECMO reducing filling of the LV.
Alternative percuataneous support is available in the form of a new impella catheter called the Impeller RP which is inserted through the femoral vein and sits across the tricuspid and pulmonary valves. An axial pump in the catheter body pulls blood from the drainage holes in the right atrium and pumps through the tip which sits in the pulmonary artery. The catheter allows around 4 L/min of RV support and is shown on the radiographic image above. This offers a good alternative to the IJ approach and the complication of an external pump are not required.
Peripheral VA ecmo may be able to provide support to LVAD patients in the post op period, as it allows decompression of the right ventricle to aid recovery, as well as providing haemodynamic support. However due to this RV offloading, filling of the LV will be reduced , and this may result in compromised LVAD flows.

14. Conclusions
Protek Duo percutaneous cannula shown to be beneficial in the setting of RVF in LVAD patients.
Multiple benefits over direct cannulation, include reduced risk of bleeding, infection and non-requirement for re-sternotomy.
Should percutaneous RVAD therapy be used pre-emptively in high risk LVAD patients? (risk scores?)
Cannula may also be beneficial for RVF in other settings
Recovery after prolonged CPB
Predicted RVF (pericardectomy, carcinoid)
Post Tx?
V-V ECMO? (no recirculation)
In conclusion, the protek Duo cannula has been shown to beneficial for right ventricular recovery in patients at the QE, with multiple benefits over traditional direct cannulation therapy.
This raises the question as to whether some high risk LVAD patients should receive this treatment pre-emptively, and should this be based on risk scores?
Finally, the protek duo may also be beneficial in other cardiac surgery settings, where a period of post op right ventricular assistance is required, or possibly in the setting of V-V ECMO?

15. Thank you
Any Questions?

16. References
Rich, Jonathan D. (2012) Right Ventricular Failure in Patients with Left Ventricular Assist Devices. Cardiology Clinics , Volume 30 , Issue 2 , 291 – 302
Alghothani, Mohamad et al. (2016) Severity of Right Heart Failure Post LVAD Implantation Predicts 1 Year Mortality, Journal of Cardiac Failure , Volume 22 , Issue 8 , S117 - S118
Argiriou, Mihalis et al. “Right Heart Failure Post Left Ventricular Assist Device Implantation.” Journal of Thoracic Disease 6.Suppl 1 (2014): S52–S59. PMC. Web. 19 Sept