Abstract 19271: Lack of Sufficient Pulsatile Flow in the Microvasculature May Contribute to Increased Microvascular Complications in Patients Implanted With Continuous Flow Left Ventricular Assist Devices

Abstract

Background: In patients on continuous flow left ventricular assist devices (CF-LVAD) support, low pulsatility has been implicated in the development of microvascular complications such as gastrointestinal bleeds and strokes. The aim of this study was to measure and compare the microvascular flow profiles of both CF-LVAD patients and age matched healthy controls. Methods: The cuff based Mobil-O-Graph system (IEM) was used to measure supine blood pressure (BP) in 6 patients implanted with a CF-LVAD. Using the captured brachial pressures and associated waveform, the inbuilt ARCSolver algorithm was used to calculate central systolic and diastolic pressures, augmentation index (AIx) and aortic pulse wave velocity (aPWV). Pulsatility index (PI) of the central retinal (CR) and mid cerebral artery (MCA) was measured using a 12MHz linear probe with vivid-Q ultrasound and 2MHz transcranial Doppler ultrasound, respectively. Similar measurements were recorded in 13 healthy, age, mean pressure and aPWV matched controls. Results: Brachial and central pulse pressures were both significantly lower in CF-LVAD patients compared to controls. In addition, PI was significantly lower in the CF-LVAD group compared to controls in the CR and MCA (Table). Conclusion: Our data provide the first evidence that pulsatile flow is significantly lower in the microcirculation of CF-LVAD patients compared to healthy controls. This lack of pulsatile flow to appropriately stimulate the endothelium and replicate normal healthy haemodynamics, may in part be responsible for the increased risk of microvascular complications in CF-LVAD patients. As this is a pilot study, more mechanistic studies assessing macro and microvascular flow haemodynamics in CF-LVAD patients are needed to understand these associations further. Table.