Cerebral vasoreactivity in HeartMate 3 patients

Area of Science:

• Cardiovascular Science
• Neurology
• Biomedical Engineering

Background:

• Continuous-flow left ventricular assist devices (CF-LVADs) like HeartMate3 (HM3) have reduced stroke rates.
• The impact of non-pulsatile flow and artificial pulse physiology on cerebrovascular function in HM3 patients is not well understood.
• Cerebrovascular metabolic reactivity (CVR) may be affected by CF-LVADs.

Purpose of the Study:

• To compare cerebrovascular metabolic reactivity (CVR) in patients with HeartMate3 (HM3) CF-LVADs versus HeartMate II (HMII) CF-LVADs and heart failure (HF) patients.
• To investigate the effect of HM3's improved hemodynamics and artificial pulse on CVR.
• To assess cerebrovascular function using breath-hold challenges.

Main Methods:

• Ninety participants (24 healthy controls, 30 HF, 15 HMII, 21 HM3) underwent transcranial Doppler ultrasound.
• Cerebral blood flow velocities (MFV, PSV, MinFV) and pulsatility index in the middle cerebral artery (MCA) were measured.
• A 30-second breath-hold challenge was used to assess cerebrovascular metabolic reactivity (CVR).

Main Results:

• HM3 patients demonstrated significantly improved CVR compared to HMII patients after a breath-hold challenge.
• HM3 patients' CVR was similar to HF patients but lower than healthy controls.
• CF-LVAD pump speed was inversely associated with CVR in HMII patients, but not in HM3 patients.

Conclusions:

• The HeartMate3 (HM3) CF-LVAD is associated with improved cerebrovascular reactivity (CVR) compared to the HeartMate II (HMII).
• Despite improvements, CVR in HM3 and HF patients remains lower than in healthy controls, suggesting incomplete reversal of cerebral hemodynamic alterations.
• Further research is needed to understand the mechanisms and long-term effects of altered cerebral hemodynamics in CF-LVAD patients.