LAUSR

Continuous-flow left ventricular assist device (LVAD) is widely used for patients with advanced heart failure. Suction events are potentially life-threatening condition which often occur following implantation, due to contact of the inflow cannula (IC) and left ventricular endocardium. Suction events can cause ventricular arrhythmia, hemolysis, or pump thrombosis. Therefore, early detection of accelerated flow around the IC is important. Echocardiography is useful for detecting the suction events. It has been reported that echocardiographic measurement of accelerated IC flow (> 1.5 m/s) suggests suction events [1]; however, detecting accelerated flow around the IC is frequently difficult because of reverberation artifacts or poor imaging (Electronic Supplementary Fig. 1a). Therefore, alternative methods are needed. Here, we present a new method for detecting suction events using flow patterns in the outflow graft (OG) of HeartMate II® (Abbott Laboratories, Lake Forest, IL, USA). In our institute, it was possible to measure OG flow in all LVAD cases, even in cases which the measurement of IC flow was impossible (Electronic Supplementary Fig. 1a–c). We performed transthoracic echocardiography with changing pump speed in 3 cases. In 2 of 3 cases, suction events occurred in high-speed setting. Visualizing an OG flow was easy in all cases from right parasternal approach. We recorded IC flow by continuous Doppler imaging and OG flow by pulse Doppler imaging. First case was a 52-year-old male. Flow speed of IC and OG was within the normal range, suggesting that suction events did not occur even in high-speed setting (Fig. 1a). Second and third cases were 50-year-old female and 68-yearold male, respectively. In contrast to the first patient, the acceleration of IC flow (> 1.5 m/s) appeared in high-speed setting, suggesting suction events. Disruption of OG flow was observed at the same phase as the peak of accelerated IC flow, reflecting sudden disruption of LVAD flow due to contact of the IC and endocardium (Fig. 1b, c). In conclusion, disruption of OG reflects accelerated IC flow. It can be a novel, alternative sign of suction events. Further evaluations of this method for clinical utility are expected.