DOI: 10.1161/circ.148.suppl_1.15424 ISSN: 0009-7322

Abstract 15424: Phase-to-Phase Short Phenomenon in a Left Ventricular Assist Device: Navigating Through Clinical and Ethical Challenges

Cesar J Benites Moya, Sam J Apple, Adhya Mehta, sheetal vasundara mathai, Diego Barzallo Zeas, Sandhya Murthy
  • Physiology (medical)
  • Cardiology and Cardiovascular Medicine

Description of Case A 59-year-old male with an axial continuous-flow left ventricular assist device (CF-LVAD) presented asymptomatically after noticing low-flow alarms. He reported extensive external driveline damage that accumulated over one year. The CF-LVAD was connected to an ungrounded cable and the driveline was repaired by the manufacturer. However, low-flow alarms continued. Log files revealed pump stoppages on all modes of power which was compatible with phase-to-phase short phenomenon (PtPSP). The patient was cannulated in case of emergent need for ECMO and upgraded to UNOS status 1 for heart transplant. Because PtPSP was considered unrepairable, the patient underwent emergent cardiac transplantation.

Discussion The CF-LVAD driveline consists of three phases, each of which is formed by two electrical wires, connected to six motor stators. PtPSP causes driveline dysfunction due to a loss of insulation between the three phases owing to multiple breaches of the insulator, causing the pump to lose power when the damaged phases come into contact. Pump stoppages are likely and unpredictable even on batteries or an ungrounded cable. Patients may notice alarms associated with low flow, pump speed drops, or pump arrest. PtPSP is unrepairable, and pump exchange or urgent heart transplantation are the only viable treatment options.This case highlights the ethical complexity of the care of patients with advanced heart failure, whereby subjective treatment decisions often translate to objectively different levels of priority on the heart transplantation waiting list without intrinsic measures of disease severity, which may incentivize more aggressive care.

Conclusions: CF-LVAD driveline dysfunction due to PtPSP is a clinically asymptomatic ominous scenario often uncovered by pump-controller alarms. Given the high risk of abrupt pump stoppage, a diagnosis of PtPSP necessitates emergent device exchange or explant with an orthotopic heart transplantation.

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