A Pseudotwist Pattern of LVAD Outflow Graft Stenosis - A Cautionary Tale.

Left ventricular assist devices (LVADs) play a fundamental role in treating end-stage heart failure. Outflow graft stenosis (OGS) represents a serious complication that can occur at a variable time point after the implantation, although typically of the order of months to years. Different types of OGS, both intrinsic and external, were described. Notwithstanding the etiology, this clinical scenario poses a life and health-threatening complication requiring timely and precise diagnosis followed by appropriate intervention. We present a case of a 72-years-old woman on LVAD HeartMate II (HM II) support. Three years after the index implantation, she presented with clinical symptoms of outflow graft stenosis. The patient was admitted to the hospital due to"low-flow" alarms of HMII. The CT scan revealed distal outflow graft stenosis suggestive of kinking of the graft. Subsequent percutaneous transluminal stenting of the graft was performed. However, after the intervention, signs of hemodynamic compromise persisted. Both angiography and repeated CT scans verified peculiar pattern of the proximal shift of the stenotic segment relative to the implanted stent. Given this specific feature, a diagnosis was reclassified as a previously reported pattern of the outflow graft twist scenario, and surgical subxiphoid approach reexploration was indicated. On inspection, after disconnecting the bend relief from the pump body massive"gelly mass" plasma transudate located in the interspace between the graft and the bend relief was observed. Immediately after removing compressing gelly mass, hemodynamic and pump parameters promptly resolved, and the bend relief was re-attached. Further patient follow-up remains uneventful to the date. Our observation suggests that the diagnostic assessment of the outflow graft stenosis may be confusing and challenging. As plasma transudate likely develops over an extended period of time once a distal orifice of the bend relief already gets entrapped within the adjacent adhesion, the outflow graft may become contained within incompressible interspace while limited by tight connection to the pump body. That said, the graft constriction migration upon stenting can easily get misdiagnosed as a pattern suggestive of the intrinsic twist instead of correct"pseudotwist" diagnosis associated with the external contained compartment compression. [ABSTRACT FROM AUTHOR]