Fig. 22.1
RV Failure after LVAD implantation via MS (direct cannulation of RA and PA), explantation via re-sternotomy
22.4.2 Minimally Invasive Placement/Withdrawal
Several reports have shown the feasibility of minimally invasive RVAD insertion using different approaches. Cohn et al. described RVAD insertion through vessel grafts with bedside removal [9].
Strauch et al. suggested a modified technique for RVAD insertion via sternotomy [10].
Minami et al. described cannulation of the outflow graft through the right pulmonary artery between the ascending aorta and the superior vena cava using Seldinger technique, to avoid excessive adhesion dissection in cases of reoperation [11].
22.4.3 After LVAD Placement Through Left Lateral or Bilateral Minithoracotomy
Transpericardial outflow cannulation of main PA by Seldinger technique.
After localization of the main pulmonary artery with needle under TEE monitoring, two additional purse string sutures (5–0 polypropylene) were placed at the pericardium to protect the left lateral aspect of the artery. Pressure measurement and blood gas analysis confirmed correct position of the needle in the lumen of the main pulmonary artery. The venous cannula of RVAD was advanced through the inferior vena cava into the cavum of the right atrium using the Seldinger technique. The location and hemostasis were secured by purse string sutures and cutaneous fixation. After that the wound was provisionally closed and the skin adapted with metal clamps (see ◘ Fig. 22.2).
Fig. 22.2
RV failure after LVAD insertion via left lateral thoracotomy
Venous cannulation via a femoral vein and transpericardial outflow cannulation of the main pulmonary artery by Seldinger technique RVAD
Our approach is limited if there are severe adhesions after left lung decortication or previous thoracic surgery or lack of TEE to localize the main pulmonary artery transpericardially. Using self-expanding smart venous cannulas may minimize the risk of venous thrombosis and maintain sufficient perfusion of the leg if RV recovery is expected to be prolonged [12]:
PA cannulation via RV apex (Personal communication Dr. Woo, Dr. Loebe, Berlin MCS Meeting 2009) and femoral vein for drainage
Peripheral VA ECMO
Peripheral venoarterial ECMO for maintaining systemic circulation may be of value. However, the ECMO flow in this approach is limited to 2–4 l/min and may carry an additional thromboembolic and bleeding risk for the patient:
Impella RP (Abiomed).
Son et al. presented an animal and cadaver feasibility study to show possible means of VAD implantation via right thoracotomy [13].
22.5 Management and RVAD Weaning
22.5.1 Weaning
Potential for right ventricular myocardial recovery induced by mechanical assistance and exact guidelines for right ventricular assist device weaning are still challenging. Most of publication did not provide exact criteria for weaning start.
Most of the groups suggest first echocardiographic weaning study in the intensive care unit after 24–72 h of support. Low-dose inotropic support with milrinone (0.25 g/kg/min), dopamine (3.0 g/kg/min), or epinephrine (0.05 g/kg/min) was initiated before attempting to wean the device. Signs consistent with RV recovery included increased amplitude of the pulmonary arterial waveform, no need for escalation of inotropic support, maintenance of a low central venous pressure (CVP), and improved RV systolic function on echocardiography [5, 14].
In our experience between January 2008 and October 2013, 49 of total 584 LVAD recipients required implantation of a temporary RVAD (Thoratec® CentriMag®) for treatment of RV failure after the initiation of LVAD support. Thirty-three patients on RVAD reached candidacy for weaning after a median of 6 (range 1–36) days of full RVAD support. Four of them were non-weanable and bridged to the heart of sepsis and late tamponade (both died on RVAD after 25 and 39 days). Weaning patients (n = 27) required a median support duration of 20 (range 3–65) days (see ◘ Fig. 22.3) [14].
Fig. 22.3
Temporary RVAD between January 2008 and October 2013
Based on this center experience, we introduced RVAD weaning protocol. Briefly, after RVAD insertion, full flow (5–7 l/min) of VAD, minimization, or freedom from catecholamines, euvolemia, and support of end-organ function is targeted.
Important is to maintain a balance between RVAD and LVAD flow – maximal flow without lung congestion confirmed by echocardiography and lung function. In any case of lung suggestion, RVAD overflow has to be ruled out first. Membrane oxygenation included into RVAD circuit may be a therapy option in case of refractory lung failure.
After 3–4 days of support, first echocardiographic assessment of RV function is performed, ruling out significant pericardial effusion, high degree of tricuspid insufficiency, interventricular septum position, and RV systolic function.
Criteria for start to reduce RVAD flow in absence of cardiac tamponade are:
SR or absence of arrhythmias
Freedom from or low-dose vasopressors
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