The Thoratec HeartMate II ventricular assist device (Thoratec Corp., Pleasanton, CA) is an axial flow rotary pump constructed of titanium (Fig. 10.4) and is the pump used most commonly at our institution. It is substantially smaller than the HeartMate XVE and requires a less invasive operative approach. It can generate flows up to 10 L/min operating at pump speeds of 6,000–15,000 RPM. Inflow is via the LV apex and outflow is via the ascending aorta. The pump housing is implanted in the preperitoneal space, and given its small size, only a small pocket is necessary. A small percutaneous driveline exits the skin in the right upper abdomen. Systemic anticoagulation is necessary. The HM II is approved by the FDA for BTT and DT [37].

Dr. Miller and colleagues recently reported the results of the prospective, multicenter HeartMate II trial [38]. Of the 133 patients with end-stage heart failure who underwent implantation of a HM II, the primary endpoint, which was defined as the proportion of patients, who, at 180 days, had undergone transplantation, had undergone cardiac recovery, or had ongoing mechanical support while remaining eligible for transplant, was reached in 100 patients (75 %). The median duration of support was 126 days. The survival rate during support was 75 % at 6 months and 68 % at 12 months. There was also significant improvement in functional status as well as quality of life. Adverse events included postoperative bleeding, stroke, RHF, and percutaneous lead infection. Pump thrombosis occurred in two patients [38].

Dr. Pagani and colleagues reported in 2009 18-month follow-up on 281 patients who underwent a HM II implantation as a BTT. Of the 281 patients, 222 (79 %) underwent transplantation, underwent LVAD removal for cardiac recovery, or had ongoing LVAD support [39]. Actuarial survival on support was 72 % at 18 months. At 6 months, there were significant improvements in functional status and 6-min walk test and in quality of life.

The Jarvik 2000 (Jarvik Heart Inc., New York, NY) is an electromagnetically actuated pump, which is constructed of titanium, measures 2.5 cm in diameter, and weighs 90 g (Fig. 10.5). It has a displacement of approximately 25 cm³. Titanium impeller blades are held in place by ceramic bearings. The impeller rotates at speeds of between 8,000 and 12,000 RPM and can generate flow of up to 7 L/min. A unique feature of this device is that the actual pumping chamber is implanted within the left ventricle. The outflow graft is anastomosed to the descending thoracic aorta. Surgical implantation of the device is typically accomplished through a left thoracotomy [40]. The pump can be operated via a fixed-rate analogue system or a variable-speed microprocessor-controlled system.

There are several versions of the Jarvik 2000 device, which are differentiated by their energy source. There is a percutaneous model that has a single driveline that exits through the patient’s anterior abdominal wall. There is a version that contains skull-mounted pedestals used with cochlear implants, where a titanium pedestal is screwed into the skull with a transcutaneous connector that attaches to the power cord. There is also a completely implantable version that utilizes a transcutaneous energy transfer system for recharging of the battery [40, 41].

Dr. Siegenthaler and colleagues reported on 102 patients implanted with the Jarvik 2000 Heart between 2000 and 2004. Mean support time for BTT patients was 159 days. No implantable component failures occurred [42].

The Thoratec HeartMate III (Thoratec Corp., Pleasanton, CA) device is also a magnetically suspended centrifugal pump, which is powered by a magnetically levitated centrifugal impeller. It uses a transcutaneous energy transfer system for battery charging and is totally implantable [43–45]. This device has not begun clinical testing to date.

The HeartWare HVAD (HeartWare, Inc., Sydney, Australia) is a centrifugal pump with no mechanical bearings that weighs 145 g, has a displaced stroke volume of 45 cm³, and can flow up to 10 L/min at 2,000–3,000 RPM (Fig. 10.6). The inflow cannula is integrated into the left ventricle. The device is implanted in the pericardial space without the need for an abdominal incision. A single, flexible driveline that is 4.2 mm in diameter exits the anterior abdomen. The device has been tested in several centers throughout Europe with good preliminary results [45, 46]. The HVAD was recently approved for BTT in the Unites States and there is currently a DT trial underway.

CircuLite (CircuLite, Inc., Hackensack, NJ) Synergy is a partial support LVAD that can be placed intravascularly (Fig. 10.7). An inflow cannula is placed through the subclavian vein, into the right atrium, and across the interatrial septum into the left atrium. Outflow is to the subclavian artery. Computer simulation models have demonstrated that partial support devices can increase cardiac output (native heart cardiac output  +  LVAD) and decrease left ventricular end diastolic pressure (LVEDP) in moderate to severe heart failure [47]. Clinical trials are currently ongoing to evaluate the safety and efficacy of this device.

A vertical midline incision is made beginning just below the sternal notch with variable extension below the xiphoid depending on the type of device being implanted and the corresponding required pocket size. The Bovie electrocautery is used for hemostasis. A sternotomy is made. Care is taken to avoid getting into the pleural spaces unless there are pleural effusions that need to be drained. Likewise, the peritoneal cavity is not entered.

The LVAD pocket is developed posterior to the posterior rectus sheath in the preperitoneal space. Alternatively, the LVAD pocket can be developed between the posterior rectus sheath and the muscle. A portion of the left hemidiaphragm is taken down to accommodate for the LVAD. Careful attention is given to hemostasis. The device is then placed in the preperitoneal pocket (Fig. 10.8).

The device is screwed onto the tunneler. The spear end of the tunneler is then brought into the incision, pierces through the fascia just to the left of the­ ­midline in the pocket, and is tunneled to exit the skin through a previously placed circular incision in the right upper quadrant (Fig. 10.9). The exit point is generally halfway between the umbilicus and anterior superior iliac spine. The driveline is pulled though the exit site. All felt is kept on the inside. The LVAD is then positioned in the pocket.

The retrosternal fat and perithymic tissue are divided in a hemostatic fashion using the Bovie and clips. The pericardium is opened along the right side of the heart, down to the diaphragm, and then over to the left by the apex of the heart. Superiorly, the pericardium is opened up just above the aorta until the pericardial reflection. Retraction sutures are placed, creating a ­pericardial well for exposure of the heart.

The patient is fully heparinized. Two purse strings are placed on the distal ascending aorta using 3-0 Prolene suture. A purse-string suture is then placed on the anterior portion of the right atrial appendage. When the ACT is 400 s or higher, the ascending aorta is cannulated at the level of the pericardial reflection. The cannula is deaired and secured, and the line is tested. The RA is then cannulated and connected to the bypass circuit. If a tricuspid valve repair or closure of an ASD is planned, the patient is bicavally cannulated with vessel loops and snares placed around the SVC and IVC cannulas. CO₂ is also brought onto the field.

The outflow graft is measured and cut appropriately to be anastomosed to the proximal ascending aorta. It is cut with a slight bevel. A partial occlusion side-biting clamp is then applied to the proximal ascending aorta and secured to the drape (Fig. 10.10). An aortotomy is made with a 15 blade and the aortotomy is then extended with a Potts or Iris scissors. The graft is then anastomosed to the proximal ascending aorta using two 4-0 Prolene sutures. Mattress sutures are placed at the heel and toe of the graft and corresponding aorta. The graft is parachuted down (Fig. 10.11). The sutures are tied. A single-layer running anastomosis is then performed followed by application of BioGlue (CryoLife Inc., Kennesaw, GA) (Fig. 10.12). The graft is then deaired and clamped, and the anastomosis is inspected for bleeding.

The patient is then placed on CPB and kept warm. Volume is taken out of the heart. The carbon dioxide is turned on so that the field is flooded with CO₂.

After CPB is commenced, the LV apex is exposed by placing several lap pads in the posterior pericardial space, elevating the heart and bringing the apex to the middle of the field. The LV is then incised at the apex, precisely where the dimpling of the heart occurs. This is generally 2 cm to the left of the left anterior descending artery. A Foley catheter is inserted into the LV, the balloon is inflated, and the Foley is lifted up, abutting the balloon against the coring site. Coring is performed using a 14 Fr coring knife, directing the knife to the LV cavity and not the septum (Fig. 10.13). The LV is then inspected for trabeculations. Prominent trabeculations are excised and any thrombus is removed. Full thickness 2-0 Tevdek pledget sutures are placed in a horizontal mattress fashion around the circumference of the ventriculotomy (Fig. 10.14). The sutures are placed through the sewing ring of the inflow cuff, the sewing ring is seated, and the sutures are tied and cut. BioGlue (CryoLife Inc., Kennesaw, GA) is then applied onto the pledgets of the sutures and around the inflow cuff. The cannula is then inserted into the inflow housing and secured with a tie and 2–3 umbilical tapes (Fig. 10.15). The lap pads are removed, the heart is placed back in its normal position, and the LVAD is placed back in the pocket.