Hand Microcirculatory Perfusion During Simulated Simultaneous Proximal or Distal Radial and Ulnar Artery Occlusion: A Laser Doppler Study

BACKGROUND: The distal radial artery access has been proposed as an alternative route to overcome some limitations and to reduce complications of conventional radial acces. AIMS: This study aimed to compare hand microcirculatory perfusion during two experimentally induced combined-compression conditions: combined proximal radial and ulnar artery compression and combined distal radial and ulnar artery compression. METHODS: A prospective, nonrandomized, fixed-sequence, within-participant physiological study was conducted on 50 healthy volunteers. Laser Doppler perfusion imaging with PeriScan PIM III device (Perimed AB, Järfälla, Sweden) was employed to quantify palmar microvascular flux during three prespecified sequential conditions: baseline assessment, combined proximal radial and ulnar artery compression, and combined distal radial and ulnar artery compression. Ulnar-flow cessation was confirmed by Doppler ultrasound before each compressed acquisition. The primary endpoint was the within-subject difference in palmar perfusion, expressed in terms of perfusion units (PU) in the different experimental conditions. Exploratory subgroup analyses by sex and weight status (normal weight vs. overweight/obese) were performed. RESULTS: Mean palmar cutaneous microvascular flux was 58.18 ± 23.18 PU at baseline, 5.91 ± 4.48 PU during proximal combined compression, and 28.46 ± 12.69 PU during distal combined compression. At the individual-participant level, residual flux corresponded to 10.9 ± 8.5% and 50.4 ± 15.8% of baseline during proximal and distal combined compression, respectively. In the primary paired comparison, residual palmar cutaneous microvascular flux was significantly higher during distal than during proximal combined-compression condition (mean paired difference, 22.56 PU; Bonferroni-adjusted 95% CI, 18.58-26.53 PU; adjusted p < 0.001). Exploratory condition-by-sex (p = 0.265) and condition-by-weight-status (p = 0.642) interactions were not statistically significant. CONCLUSIONS: This is the first study to directly compare palmar perfusion during combined proximal versus distal radial and ulnar artery compression using laser Doppler perfusion imaging. The less impaired perfusion during simulated distal radial and ulnar artery occlusion supports a physiological hypothesis regarding the influence of radial compression level on residual cutaneous microvascular flux, particularly when ulnar flow is compromised. However, confirmation in randomized, counterbalanced studies and in patients undergoing coronary procedures is required.