Virtual dissection and experimental analysis of the superior venous system: Normative values and catheterization implications

Background Venous lengths are a critical factor in selecting optimal central venous catheters. This study aimed to determine normative data for the superior vena cava (SVC) and its associated segments, including the SVC to axillary vein. Centerline vessel measurements, derived from realistic 3D geometries, involve tracing a curved line along the central axis of blood vessels using computer algorithms enabling precise evaluation of length and diameter. Methods Radiological imaging data were obtained from multiphase postmortem CT-angiography for the different SVC segments. Centerline measurements were analyzed to obtain normative values, compare them with anthropomorphic landmarks, and realize prediction models. Results Between January 2018 and October 2020, 219 subjects were retrospectively included (ethical committee registration BASEC-2021-00924). Mean centerline length ± standard deviation (in mm) was 64 ± 11 for the SVC; 75 ± 17, 30 ± 7, and 47 ± 10 for the axillary, subclavian, and brachiocephalic right veins, respectively; and 90 ± 15, 34 ± 7, and 76 ± 17 for the innominate, subclavian, and axillary left veins. The coefficient of variation was around 20%. The sums of the right and left sides were significantly different (216 ± 24 vs. 265 ± 26, p<0.001), only the right side corresponded with anthropomorphic landmarks (no significant difference). A prediction model based on height, sex, and age yielded two regression equations: Right [mm] = 57+0.8*height+11.1*sex+0.3*age; Left [mm] = 104+0.7*height+13.7*sex+0.6*age. Conclusion The results showed good to acceptable inter-subject variation in SVC segment lengths. Height, sex, and age were identified as moderate predictors of vessel length.