In the United States, at least 5 million persons have heart failure at any given time, and
more than 550,000 new cases of heart failure are diagnosed each year. Almost 20% of heart
failure patients require intravenous inotropic therapy, left ventricular assist device (LVAD)
therapy, and/or cardiac transplantation (1). Because the latter option is limited by the
scarcity of donor hearts (2) and because LVAD therapy has been shown to result in superior
survival in heart failure patients ineligible for transplantation (3), implantable LVADs
are being used with increasing frequency and for longer periods. These devices include the
HeartMate XVE LVAD (HM-XVE) (Thoratec Corporation, Pleasanton, California) (4), a pulsatile
pump that has been approved by the United States Food and Drug Administration for destination
therapy. In contrast, newer, axial-flow LVADs—such as the HeartMate II (HM-II) (Thoratec)—are
smaller, more reliable, and more durable than current pulsatile pumps and, therefore, suitable
for a broader patient population.
Experience has shown that the HM-XVE LVAD offers durable and reliable mechanical support
in the first year but has a high risk of life-threatening failure after 18 to 24 months
(5). Reoperative surgery in these patients can be challenging, especially when pump failure
necessitates urgent device exchange. In our early experience with HM-XVE exchange, we performed
a redo sternotomy to optimally expose the outflow graft. As we gained experience with the
exchange procedure, however, we found that we could expose enough of the pump and graft
by performing a left subcostal incision and extending it slightly past the midline, thereby
avoiding a full sternotomy (6). With this approach, exchanging a HM-XVE for the HM-II axial-flow
pump can be accomplished with low morbidity and mortality.
- After endotracheal anesthesia has been induced and a transesophageal echocardiography
probe inserted, the patient is placed in the supine position, with the groin easily accessible
for cardiopulmonary bypass cannulation.
- The common femoral artery and common femoral vein are exposed surgically and are cannulated
by means of the Seldinger technique, using a 21F cannula for arterial cannulation and
a 30-32F cannula for venous cannulation (Fig. 1).
- A left subcostal incision is performed and is extended 2 cm to the patient’s right
side as a limited chevron incision (Fig. 2). The incision is continued
downward directly to the HM-XVE’s hardware pocket. By confining dissection to the
pump pocket, one can avoid entering abdomen. A Thompson retractor provides excellent
exposure (Fig. 3).
- Dissection is performed to expose the HM-XVE inlet and outlet cannulas, as well as the
outflow graft and the LVAD itself (Fig. 4). If the outflow graft cannot
be adequately exposed in this manner, a right anterior minithoracotomy is performed to
expose the outflow graft in the chest. Once an adequate length of outflow graft is available
for clamping and creation of a graft-to-graft anastomosis, attention is turned to the
- The inlet cannula is dissected to expose the base of the sewing ring and the Silastic
inlet, in its entirety. Limited dissection of the diaphragm surrounding the inlet is
done around the apex to give the surgeon enough mobility to fully expose the inflow cannula,
which is secured with electrician’s tape (Fig. 5).
- Full heparinization is instituted, and the patient is placed in the Trendelenburg position.
Cardiopulmonary bypass is started, and the HM-XVE LVAD is turned off. By dividing the
driveline, one can attain mobility of the whole LVAD (Figs. 6 and 7),
which can further assist in the sometimes difficult task of exposing the sewing ring
base. The outflow graft is clamped and divided, leaving enough of a rim to anastomose
it to the HM-II’s outflow graft. The electrician’s tapes are cut and removed
gently without damaging the inlet cannula (sewing-ring Silastic tube). The pump’s
inlet cannula is then gently removed from the Silastic inlet cuff.
- During this period, the presence of air in the ventricle and ascending aorta is monitored
continuously with transesophageal echocardiography. The HM-II inlet cannula is inserted
into the inflow cannula and secured with electrician’s tape (Fig. 8).
The HM-II outflow graft is cut to an appropriate length, leaving a beveled edge. A graft-to-graft
anastomosis to the HM-XVE outflow graft is then created with continuous, running 5-0
polypropylene sutures (Fig. 9). Both the LVAD and the left ventricle
are de-aired (Fig. 10).
- The HM-II’s driveline is tunneled toward the right subcostal area and brought
out just above the exit site of the HM-XVE driveline (Fig. 11). A single
36F chest tube is inserted. Meticulous control of bleeding is essential. Because all
patients undergoing device exchange will develop a coagulopathy, only the skin is closed.
The next day, the patient is returned to the operating room for washout of the abdominal
incision site, closure of the abdomen, and removal of the HM-XVE driveline.
Postoperatively, appropriate antibiotic prophylaxis is carried out with broad coverage,
including an antifungal agent. The chest tube can usually be removed the day after surgery.
Anticoagulant therapy is then started according to our protocol (7). Nasogastric-tube suction
should be continued until the patient’s bowel activity is resumed, after which the
nasogastric tube is removed and oral feeding begun, as tolerated.
Surgical Tips and Pitfalls
- By removing the xiphoid, the surgeon can better mobilize and expose the outflow graft
of the HM-XVE.
- If the HM-XVE device was placed intraabdominally, it is safest to enter the abdomen
at the level of the liver to prevent injury of nearby organs.
- If an HM-XVE LVAD pocket is present, cultures should be obtained for intraoperative
gram-stain analysis. If there is any possibility of infection, the replacement LVAD should
be inserted intraabdominally.
We have found that the pulsatile HM-XVE LVAD can be exchanged for the newer, axial-flow
HM-II pump with low morbidity and mortality. According to Lietz and coworkers (8), the likelihood
of device exchange or fatal device failure is 17.9% and 72.9% at 1 and 2 years, respectively.
Because our subcostal approach entails shorter operative and recovery times and fewer transfusion
requirements (9), it simplifies the exchange procedure while precluding the need for a median