A Comparison of Middle Cerebral Artery and Central Retinal Artery Hemodynamics in HM II Patients

Purpose In the normal, pulsatile circulation, the hemodynamic pattern of the middle cerebral artery (MCA) differs from the central retinal artery (CRA). Whether continuous flow from a left ventricular assist device (LVAD) alters this relationship is not known. Since serious adverse events in different end-organs, such as stroke and GI bleeding, are frequent in LVAD patients, comparing hemodynamics in different arterial beds may enhance our understanding of the specific pathophysiology of these complications. Hypothesis Because of continuous flow, hemodynamic patterns between the MCA and CRA are more similar in HeartMate II (HM II) patients compared with healthy individuals. Methods MCA and CRA time-averaged maximal flow velocity (TAMAX), pulsatility index (PI) and resistance index (RI) were determined using Doppler ultrasound with angle correction, in 20 HM II pts and 21 healthy individuals. To test the study hypothesis, data were statistically analysed for both group differences and group variances. Results Although PI and RI were markedly lower in HM II patients in both the MCA and CRA ( P Conclusion The typical differences that are observed in small- and microcirculatory hemodynamics of healthy individuals are altered in HM II patients. Notably, the wide ranges of haemodynamics observed in the HM II group may carry important implications with respect to the pathophysiology of specific end-organ complications, and, eventually, the identification of high-risk patients.