1. Unique Cannulation Technique and Atrioventricular Valve Excision for HeartWare HVAD in the Small Fontan Patient 
Christopher E. Mascio, MD 
Operative Techniques in Thoracic and Cardiovascular Surgery 
Volume 21, Issue 4, Pages (December 2016)
DOI: /j.optechstcvs
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2. Figures 1 and 2
Because the HVAD is placed for bridge to transplant in a Fontan with ventricular failure, the goal is to create volume reservoir for the device to be able to fill without obstruction. In small patients, internal cardiac structures are a risk for inflow obstruction. Excising the atrioventricular (AV) valve accomplishes the goal of providing the largest possible volume reservoir. When excising the AV valve, the sewing ring should not be secured to the right atrium. Instead, after cross clamping and snaring the fenestration, a right atriotomy should be performed at the planned site of HVAD implantation. Through the atriotomy, the entire AV valve apparatus is excised, including papillary muscles. It is important to excise any tissue that could potentially cause inflow obstruction.
Operative Techniques in Thoracic and Cardiovascular Surgery  , DOI: ( /j.optechstcvs )
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3. Figures 1 and 2
Because the HVAD is placed for bridge to transplant in a Fontan with ventricular failure, the goal is to create volume reservoir for the device to be able to fill without obstruction. In small patients, internal cardiac structures are a risk for inflow obstruction. Excising the atrioventricular (AV) valve accomplishes the goal of providing the largest possible volume reservoir. When excising the AV valve, the sewing ring should not be secured to the right atrium. Instead, after cross clamping and snaring the fenestration, a right atriotomy should be performed at the planned site of HVAD implantation. Through the atriotomy, the entire AV valve apparatus is excised, including papillary muscles. It is important to excise any tissue that could potentially cause inflow obstruction.
Operative Techniques in Thoracic and Cardiovascular Surgery  , DOI: ( /j.optechstcvs )
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4. Figure 3
After the induction of anesthesia and tracheal intubation, appropriate monitoring lines and devices are placed. The patient is positioned supine with the head turned slightly to the left. A roll is placed behind the shoulder to slightly elevate the neck and sternum. Consideration should be given to cannulation of the right carotid artery and right jugular vein for cardiopulmonary bypass in appropriate circumstances (multiple reoperations with adherence of cardiac structures to the posterior sternum, or a very short ascending aorta such as that often seen after staged palliation for hypoplastic left heart syndrome). Neck cannulation is not necessary but facilitates placement of a cross clamp and cardioplegia cannula while leaving enough room for the outflow graft anastomosis. (A) The existing midline scar is used to perform the reoperative sternotomy. Existing sternal wires or sutures are removed, and care is taken to divide the sternum and dissect each hemi sternum off of the mediastinal structures. One of the advantages of cannulating the right atrial free wall of the common atrium is that the entire ventricular mass does not need to be dissected free of adhesions. (B) The right side of the pericardium is dissected including the superior vena cava, pulmonary artery, right atrium, and extra cardiac conduit. The fenestration should be identified and encircled with a tourniquet (left loose at this time). If neck cannulation is not employed, purse strings are placed in the distal aorta, superior vena cava, and inferior vena cava. Heparin is administered and arterial and bicaval cannulation is performed.
Operative Techniques in Thoracic and Cardiovascular Surgery  , DOI: ( /j.optechstcvs )
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5. Figure 4
Once the dissection is complete (it should be emphasized once again that the entire ventricular mass does not need to be dissected for this cannulation technique), a location for HVAD implantation is chosen on the free wall of the right atrium. The HVAD sewing ring is placed on this area and the internal circumference is traced with a sterile marking pen. (A) Eight to 12 valve sutures with pledgets are placed circumferentially around the tracing of the sewing ring. Our latest technique involves using 8 sutures with extra-large pledgets in an overlapping technique. Felt spacers (created by tracing the sewing ring 5-7 times on a large piece of felt and cutting out the felt rings) can be used to limit the length of the inflow cannula that protrudes into the heart. The felt spacers are held together along with the sewing ring, and the entire complex is sutured together using 4 interrupted sutures placed 90 degrees apart. The sutures are then passed through the sewing ring or felt complex, and the ring is secured to the free wall of the right atrium. It is important to keep the pin of the sewing ring facing anteriorly to facilitate securing the HVAD to the ring. (Alternatively, if atrioventricular valve excision is planned, the sutures are not placed through the sewing ring at this time and a right atriotomy is created (after placing the cross clamp) within the suture ring to facilitate valve excision.) Cardiopulmonary bypass is commenced and a cardioplegia cannula is placed in the proximal aorta. A cross clamp is placed on the aorta and cardioplegia is administered. Once the cardioplegia administration is complete, the fenestration is snared and a (B) cruciate incision is made inside the sewing ring, and the (C, D) coring device is then used to create a proper atriotomy for the HVAD.
Operative Techniques in Thoracic and Cardiovascular Surgery  , DOI: ( /j.optechstcvs )
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6. Figure 5
The HVAD is then placed through the sewing ring such that it is flush with the sewing ring and no inflow cannula is visible. The pin is then tightened with the tool that comes with the HVAD. (A, B) If the atrioventricular valve has not been excised, the felt spacers that were added to the sewing ring will keep the inflow cannula away from the atrioventricular valve tissue, preventing inflow obstruction. Attention is then turned to the outflow graft. The outflow graft is a 10-mm diameter gel impregnated polyester graft. It has considerable stretch to it, and this should be considered when determining the length of the graft necessary to reach the aorta without excessive redundancy or tension. In small patients utilizing right atrial free wall cannulation, the outflow graft will be short. A site on the greater curvature of the ascending aorta generally works well for the outflow graft anastomosis. Also, it is necessary to remove most of the strain relief. Typically, 1-3 segments of the strain relief will remain. Once the graft is cut to an appropriate length and the excess strain relief has been removed, the site on the aorta chosen for outflow graft anastomosis is incised with a scalpel and then enlarged to match the 10 mm outflow graft. Our practice has been to not only incise the aorta, but also excise some aorta to create a true opening in the vessel, not just a flap opening. The anastomosis is completed with monofilament suture in continuous fashion.
Operative Techniques in Thoracic and Cardiovascular Surgery  , DOI: ( /j.optechstcvs )
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7. Figure 6
At this point, a driveline exit site is chosen, typically in the left upper quadrant of the abdomen. In patients with a gastrostomy tube or other reason that would preclude use of the left upper quadrant, we have utilized the right upper quadrant of the abdomen. (A, B) A scalpel is used to make a small incision at the chosen site and the tunneling device is carefully passed through the skin into the mediastinum. Care is taken to avoid injuring intra-abdominal structures and the heart. The driveline then screws onto the tip of the tunneling device and the driveline is pulled through the pathway and through the skin incision. The driveline is pulled until the woven polyester fabric is at the skin edge. No fabric should be beyond the skin edge. The driveline is passed to the perfusionist and connected to the power source. At this time, the distal outflow graft is clamped and the heart and aorta deaired. The cross clamp is then removed. A large bore needle (19-gauge) is placed in the distal outflow graft to assist in deairing. After arranging for transesophageal echocardiography (TEE), cardiopulmonary bypass flow is weaned slightly, and the HVAD is started at 1800 revolutions per minute. The HVAD is deaired and the needle is removed from the outflow graft. The needle site is repaired with a pledgeted suture. The clamp on the outflow graft is removed. The patient is ventilated, and cardiopulmonary bypass flow is weaned as HVAD speed is increased in increments of 100 RPM. The careful increase in pump speed under TEE guidance will help prevent collapse of the heart onto the device. Once completely off cardiopulmonary bypass, attention is turned to sternal closure. We have kept the TEE in place during sternal closure to assess if there are any changes in the relationship of the HVAD to the internal cardiac structures that could cause inflow obstruction. Another technique that we have found useful is to completely open the right pleura. Consideration should also be given to incising the pericardium posteriorly, stopping just before the phrenic nerve. These maneuvers will allow the HVAD to sit slightly in the right pleural space and permit sternal closure without impairing filling of the device. In small patients, there will be a considerable length of woven polyester fabric present in the mediastinum. To prevent this fabric from adhering to mediastinal structures and making explantation extremely difficult, it is advisable to wrap the woven polyester fabric in polytetrafluoroethylene (PTFE). We have employed either a PTFE tube graft and opened it longitudinally, or a thin sheet of PTFE to cover the fabric driveline. Also, because the HVAD sits close to the right lung hilum, we have wrapped or covered the HVAD with a sheet of PTFE. Finally, the outflow graft will become densely adherent to mediastinal structures and should also be covered with PTFE, again utilizing either a PTFE tube graft opened longitudinally or a PTFE sheet.
Operative Techniques in Thoracic and Cardiovascular Surgery  , DOI: ( /j.optechstcvs )
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