Use of Retrospectively Gated CT Angiography to Diagnose Systolic LVAD Inflow Obstruction

Abstract

Assessment of patients with left ventricular assist devices (LVADs) can be challenging, and multiple modalities are sometimes necessary to arrive at the accurate diagnosis. We describe two patients with persistent heart failure symptoms after HeartMate II LVAD placement. After initial evaluation was unrevealing, retrospectively gated computed tomographic angiography (CTA) was used to diagnose partial inflow obstruction, leading to important changes in management. We describe the techniques and role of retrospective gating and discuss functional assessment by CT as well as future applications.

Role of computed tomography angiography for HeartMate II left ventricular assist device thrombosis

“…No current literature validates performing inflow cannula adjustment during device exchange to prevent recurrence of thrombosis. However, both our experience and case reports 23,24 have shown that patients who had an inflow repositioning (or exchange to in intrapericardial pump) due to a concerning CTA finding had good prognosis after reoperation. A prospective study with a larger sample size is necessary to test our hypothesis in a clinically meaningful way.…”

Left Ventricular Assist Device Pump Obstruction Reduces Native Heart Efficiency

“…This prepump source of pump obstruction (PO) accounts for 25% of LVAD obstructions, and they form gradually, not suddenly, which makes detection difficult and likely underreported [5][6][7]. Early detection of PO is critical for improving outcomes and relies primarily on changes in LVAD power consumption followed by echocardiographic or computerized tomography evaluation, but they can detect only large obstructions (>75% area) [6,[8][9][10]. Innovative strategies such as thromboelastography to assess hypercoagulability and changes in the acoustic vibrations to signal additional inertia within the LVAD have yet to gain widespread traction [11,12].…”

Acoustic Characterization of Axial Flow Left Ventricular Assist Device Operation In Vitro and In Vivo

“…X-ray and computed tomography typically cannot visualize clots within the radioopaque pump housing, and echocardiography is limited by physical constraints within the chest, pump housing, and inflow and outflow grafts. 2,3 Cardiologists often rely on laboratory data, and limited pump diagnostics such as calculated flow, pulsatility, and power to diagnose pump thrombus or nonspecific clinical indicators including stroke, embolism, and signs of decreased system perfusion. [3][4][5] Consequently, there is a clinical need for a noninvasive method of characterizing pump functionality.…”

“…2,3 Cardiologists often rely on laboratory data, and limited pump diagnostics such as calculated flow, pulsatility, and power to diagnose pump thrombus or nonspecific clinical indicators including stroke, embolism, and signs of decreased system perfusion. [3][4][5] Consequently, there is a clinical need for a noninvasive method of characterizing pump functionality. 6 Mansy et al 7 demonstrated the utility of using electronic stethoscopes and postprocessing of acoustic data in detecting changes in amplitude and spectral energy distribution after obstruction of blood flow in hemodialysis grafts.…”