Carotid duplex ultrasound changes associated with left ventricular assist devices.

Background: Carotid duplex ultrasound (CDUS) is often used as a screening test in cardiac patients. Significant cardiac dysfunction may affect the accuracy of CDUS because of alterations in the cardiac cycle. Left ventricular assist devices (LVADs) are frequently implanted as a bridge to cardiac transplant. A review of CDUS in patients with LVADs was performed to assess their influence on arterial waveforms and velocities.

Methods: Patients with LVADs undergoing carotid duplex in our Intersocietal Commission for the Accreditation of Vascular Laboratories (ICAVL)-accredited vascular laboratory were identified. The carotid waveforms were analyzed qualitatively and quantitatively. Common carotid artery (CCA) and internal carotid artery (ICA) peak-systolic and end-diastolic velocities (PSV and EDV) were recorded as ICA/CCA velocity ratios. In patients with prior CDUS, the changes between these values were analyzed before and after LVAD placement.

Results: Of the 14 patients with LVADs treated in our institution over the past 2 years, 4 had CDUS (8 ICAs). Mean age was 57 years, and 3 of the 4 patients were men. All patients were free of cerebrovascular symptoms. Qualitatively, there was significant blunting of the CCA and ICA waveforms noted in all 8 ICAs. The degree of stenosis was reported as ≤15% in 7 ICAs and 15-45% in 1 ICA. The mean ICA PSV was 61.8 cm/sec. Two patients (4 ICAs) had CDUS before and after LVAD placement. Comparing pre- and post-LVAD values, the mean ICA PSV decreased by 42% (54 cm/sec; P = 0.04) and EDV increased by 51% (17 cm/sec; P = 0.3). The PSV and EDV ratios were unchanged. Overall assessment of category of stenosis was unchanged in 2 ICAs (≤15%), one decreased from moderate to mild (45-70% to 15-45%), and one ICA changed from 45-70% to ≤15% based on the decreased ICA PSV.

Conclusions: The presence of an LVAD has a significant influence on CDUS findings. There is a qualitative change in the ICA with blunting of the waveform, and a quantitative change with a decreased PSV and an increased EDV. Compared with pre-LVAD placement, there is a significant decrease in PSV which may affect the accuracy of CDUS using velocity-based criteria. Further study into the accuracy of CDUS in patients with LVADs is necessary.