Teaching Case

A 56-year-old male patient with an end-stage heart failure in whom a ventricular assist device was implanted as a bridge to transplantation. After the surgery a CT was performed to rule out thrombus formation after a prolonged arrhythmic episode.

Plain thorax radiography after VAD system implantation shows an enlarged heart with a pump overlying the left ventricle silhouette and its drive-line (Fig. 1).
Computer tomography shows the pump with the integrated inflow cannula and the tube connection to the ascending aorta. No thrombus formation was confirmed (Fig. 2, 3).

Ventricular assist devices (VAD) are mechanical pumps indicated for end-stage heart failure. VADs are used as a bridge to transplantation, bridge to myocardial recovery and in some countries as an alternative for patients ineligible to transplantation (“destination therapy”) [1].

The first assist device was implanted by DeBakey [2] in 1963. This circulatory support system consists of a pump that takes over the function of a falling ventricle, the pump is connected directly to the ventricles, from which the blood exits through a tube to the greater vessels. The VADs are run by an external computer (controller) that is connected to the pump by a drive-line.

Ventricular assist devices can be classified as short-term (for myocardial recovery) or as long-term devices (used as a bridge to transplantation or for destination therapy) [3]. There are two basic types of VADs, the left ventricle assist device (LVAD) and the right ventricle assist device (RVAD); both of them can be used at the same time, called biventricular assist device (BIVAD). The LVADs divides into two categories: one with a pulsate flow and one with a continuous flow [1].

Radiologists should be familiarized with this devices and how they appear on the different imaging techniques.

We present a case of a 56-year-old male patient with end-stage heart failure in whom a LVAD was implanted as a bridge to transplantation. The device implanted was a third generation LVAD (HeartWare) with a continuous flow run by a centrifugal pump. The inflow cannula is integrated to de pump and is inserted directly to the left ventricular apex; the outflow cannula is connected to the ascending aorta. The small size of the pump (with a displaced volume of 50 mL) allows its implantation in the pericardial space [3]. Computer Tomography (CT) can be used for preoperative planning [3], and in a postoperative scenario to rule out possible complications such as haemorrhage, pericardial tamponade, thrombus formation, right heart failure and infection [1, 3].

The CT ideal protocol should be a contrast-enhanced CT with retrospective ECG-gating when assessment of the inflow cannula and the left ventricle chamber is needed. CT can be performed without ECG-gating if the study is centred to evaluate possible driveline infection to reduce radiation dose [3].

Magnetic resonance (MR) is contraindicated for assessment of VADs [3].