Total Artificial Heart

Last updated: December 27, 2016

Orlando Debesa

Dr. Denton Cooley, in 1969, was the first surgeon to successfully implant a total artificial heart in a human being. He founded the Texas Heart Institute in 1962. 

Facts

  • 1,374 days in the longest a patient has been supported on the TAH (Syncardia)

  • central venous catheters can become entrapped in the tricuspid valve and can lead to device malfunction and circulatory collapse (Zimmerman et al, ASAIO Journal 2010)

    • Attending must be present​

    • the tip of the guide wire and catheter line should not enter the right atrium

    • make sure on xray that the catheter is not in the right atrium

  • has a 79-87% success in bridge to transplantation

  • Syncardia total artificial heart is the only FDA approved TAH in clinical use and was first introduced in 1982 as the Jarvik-7 heart

Indication

  • biventricular failure

  • left ventricular failure with prior mechanical valves

  • post infarction ventricular septal defect

  • LV failure with severe anatomical damage (VSD, AV disruption)

  • intractable malignant arrhythmias

  • massive ventricular thrombus

  • cardiac allograft failure

  • hypertrophic cardiomyopathy

  • restrictive cardiomyopathy

  • complex congenital heart disease

  • aortic root aneurysm/dissection

Contraindication

  • BSA < 1.7 m2

  • anteroposterior diameter at the level of 10th vertebral body <10cm

  • placement in smaller patients is possible by displacing the device into the left chest although this increases the risk for left sided pulmonary vein and bronchus compression (a smaller sized device for use in smaller patients is being developed and is expected in the future)

Syncardia Total Artificial Heart Device

  • 2 polyurethane ventricle chambers

  • each chamber has a maximum stroke volume of ~ 70 ml

  • each chamber has 2 tilting disc valves (Medtronic Hall, 27 mm inflow, 25 mm outflow) to direct blood inflow and outflow

  • each chamber is pneumatically driven by a separate driveline connected to a driver externally 

  • the Dacron aortic and pulmonary grafts are sealed with CoSeal Surgical Sealant 

  • The grafts and devices are soaked in rifampin

Usual Settings

  • Pump rate: 120

  • systolic duration: 50%

  • right drive pressure: 60mmHg

  • left drive pressure: 200mmHg

  • vacuum: 12

Operative Techniques/Pearls

  • median sternotomy

  • intramuscular tunnels for pneumatic drivelines are created/maintained with two 1" Penrose drains

  • cardiopulmonary bypass initiated: ascending aorta is cannulated distally and both cavae are cannulated through the right atrium (vs direct cannulation of the SVC and IVC) to preserve those sites for heart transplant

  • aortic cross clamp placed

  • leave both native atria in place as well as 1-2 cm of native ventricle around each AV valve plane preserving both annuli of the mitral and tricuspid valve

  • coronary sinus is oversewn (including a PDA if present)

  • preserve as much length of the pulmonary artery as possible

  • ascending aorta is transected at the sinotubular junction

  • left atrial appendage is ligated to eliminate a potential source of thrombus 

  • cuffs of the TAH atrial quick connects are trimmed and sewn to their respective left and right ventricular cuffs

  • the aortic and pulmonary artery graft quick connects are trimmed; pulmonic graft is left several centimeters longer than the aortic graft to allow room for the aortic graft to pass below

  • unnecessary dissection within the pericardium is minimized to preserve tissue planes

    • ​during re-entry for transplantation, an intense pericardial inflammatory response is often seen

    • dissection through this tissue at the time of transplantation can be associated with significant blood loss and appears to be greater than what is typically seen during redo sternotomy

    • strips of Preclude are placed along the pericardial membrane, drivelines, aortic and pulmonic anastomoses to maintain avascular tissue planes (some centers use sterilized rubber tourniquets to wrap the anastomoses)

  • the most common complication following TAH implantation is bleeding; low threshold for mediastinal packing and delayed sternal closure is recommended

  • a saline breast implant (filled with 200-250 ml of saline) is used to maintain the apical pericardial space for subsequent transplant

  • TEE remains a useful tool at the end of surgery to assess for compression of the right and left atrial venous return by the device during closure

    • more common on the right (both the cava and right sided pulmonary veins) and can generally be treated with displacement of the device inferiorly and to the left. This can be secured with a heavy suture placed around the costal margin and tied to the artificial right ventricle

    • a strip of silastic is left beneath the sternum to protect the pump during re-entry for transplantation

Post-Op Management

  • usually need fluid the first few days post-op

  • nesiritide 0.005 no titration 

    • acute renal failure is frequently observed after implantation of TAH and may be related to abrupt withdrawal of BNP​ following ventriculectomy

    • supplementation of BNP appears to have protective renal effects and much needed for urination

  • anemia following TAH implantation can be profound and persistent. Nonetheless, the anemia is generally well tolerated and transfusion are limited to avoid HLA sensitization

  • follow hemolytic labs daily

  • bivalirudin

    • start at 0.005 no titration

    • advance for PTT 40-60

    • advance for PTT 50-70

    • advance for PTT 60-80

  • aspirin 81mg qday

  • trental 400mg tid

  • dipyridamole (Persantine)

  • pentoxifylline

IVC is susceptible to compression in patients with small chest cavities. The left sided pulmonary veins are also susceptible to compression by a tightly fitting device. Sometimes, anchoring both ventricles to a rib on the left chest wall may be helpful in order to laterally displace the TAH away from the IVC and left pulmonary veins (done using umbilical tape). If ventricular filling can not be maintained after chest closure. the chest is left open. 

Total Artificial Heart Surgical Animation

SynCardia

Total Artificial Heart beating Animation

SynCardia

Total Artificial Heart Overview

VCUNews

References

Role of B-type natriuretic peptide and effect of nesiritide after total cardiac replacement with the AbioCor total artificial heart. Delgado R, J Heart Lung Transplant. 2005 Aug;24(8):1166-70.

Nesiritide

  • 19-38% of TAH patients end up on dialysis

  • Mean serum BNP concentrations decreased in all patients after ventriculectomy from 725 ± 270 pg/mL to 48 ± 26 pg/mL (P = 0.006) within 6 hours

  • the time period prior to ventriculectomy, mean urine output decreased in the first six hours after TAH implant from 124 ± 54 mL/hr to 48 ± 35 mL/hr (P = 0.01)

  • After initiation of nesiritide there was an immediate increase in urine output to 163 ± 113 ml/hr

... but I would more especially commend the clinician who, in acute diseases, by which the bulk of mankind are cutoff, conducts the treatment better than others.
 
Hippocrates, 400 BC