Skin microcirculation and laser Doppler blood flow in patients supported by the Berlin heart biventricular assist...

Microcirculatory forearm cutaneous blood flow was monitored continuously and non-invasively by laser-doppler-flowmetry (LDF) in 10 patients treated with the Berlin Heart biventricular assist device (BVAD) system for end-stage heart failure (BVAD-pts). Ten normal human subjects served as controls (C). The cutaneous blood flow was measured before, during, and after external brachial artery occlusion to evaluate the postocclusive reactive hyperemia (PORH) as a standardized response. To examine micro-vasculatory responses to macro-hemodynamic changes the cardiac output (CO) was decreased by reducing the BVAD-pump rate by 20%. No significant differences in base-line LDF measurements were ascertained in the two groups. After sudden cuff pressure release (1 min later) a statistically significant (p less than 0.004) three- to fourfold blood flow increase (PORH) occurred in both groups. The period of the PORH response was altered in all BVAD-pts. The time to peak PORH values were significantly diminished (p less than 0.05) A markedly delayed return to base-line level occurred in the BVAD-pts. The 20% reduction in the BVAD-pump rate significantly decreased CO (p 0.05) and increased systemic vascular resistance (SVR) (p less than 0.01), whereas LDF levels remained unchanged.