Intravascular ultrasound imaging of the Heartmate 1000 IP left ventricular assist device

Left ventricular assist devices are increasingly used as a bridge to transplantation in patients with end-stage cardiac disease. Potential complications of these devices include thromboembolism and infection. Because conventional cardiac diagnostic techniques cannot be used to obtain an image of the interior of a left ventricular assist device, we assessed the ability of intravascular ultrasonography to obtain an image of the interior of the Heartmate 1000 IP left ventricular assist device. Feasibility of intravascular ultrasound imaging was initially demonstrated in vitro on a left ventricular assist device immersed in water. Five soft rubber masses were then placed in the device intake port adherent to the wall, and their images were obtained by intravascular ultrasonography. Excellent correlation between actual size and size as measured by intravascular ultrasonography was noted (long-axis, r = 0.98, short-axis, r = 0.89). After the device was implanted in two calves, intravascular ultrasound imaging was performed in vivo in the animals. The catheter was easily advanced through the device, and excellent images were obtained. In conclusion, intravascular ultrasonography can easily be used to obtain an image of the left ventricular assist device interior and can accurately assess the presence and size of abnormal masses inside the device. Intravascular ultrasonography may be clinically useful in evaluating cases of thrombus or vegetation related to left ventricular assist devices.