title: Physiological reflux and venous diameter change in the proximal lower limb veins during a standardised Valsalva manoeuvre.
abstract: OBJECTIVE
  the aim of this study was to provide normal values for venous diameter at rest, and venous diameter and physiologic venous reflux during a standardised Valsalva manoeuvre. The impact of the patient's sex, body mass index (BMI), and family history was investigated.
  
  
  METHODS
  eighty legs of 40 healthy volunteers were investigated in a supine position. The median age was 28 years (range 20-66 years). The common femoral vein (CFV), the proximal superficial femoral vein (SFV) and the proximal long saphenous vein (LSV) were investigated by duplex sonography. The following parameters were assessed: resting diameter (VDrest) and maximum diameter (VDmax) as well as reflux time (tr) during the Valsalva manoeuvre. The Valsalva manoeuvre was elicited by a forceful expiration into a tube system. The standard values used were a pressure of 30 mmHg, established within 0.5 seconds (s) and maintained over a time period of at least 3 s.
  
  
  RESULTS
  mean VDrest and VDmax were 8.3+/-2.2 and 11.1+/-2.8 mm in the CFV, 5.9+/-1. 3 and 7.2+/-1.6 mm in the SFV and 3.5+/-0.9 and 4.3+/-1.4 mm in the LSV. Mean values for tr were 0.61+/-0.63 s in the CFV, 0.25+/-0.26 s in the SFV and 0.28+/-0.40 s in the LSV. A BMI >22.5 kg/m2 was associated with statistically significant larger values for VDrest and tr. If adjusted for BMI, tr in the SFV and the LSV did not differ by sex. For healthy subjects with first-degree relatives suffering from varicose veins (n=19), mean VDrest in the SFV as well as VD in the LSV was significantly larger (p=0.02, 0.05, respectively). Coefficients of variation for repeated measurements (VDrest, VDmax, tr) in the same segment varied between 3.3% and 16. 4% for the three investigated sites.
  
  
  CONCLUSIONS
  normal values for VDrest and VDmax as well as reflux time during a standardised Valsalva manouevre were assessed in the proximal lower limb veins. The influences of BMI, sex and family history were investigated. The described standardised Valsalva manoeuvre led to highly reproducible results and can be recommended for further research projects or as a routine procedure for the assessment of venous reflux.
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D015992:Body Mass Index; D005260:Female; D006801:Humans; D007866:Leg / Q000098:blood supply* / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D012016:Reference Values; D015203:Reproducibility of Results; D012727:Sex Characteristics; D018616:Ultrasonography, Doppler, Duplex / Q000379:methods; D014636:Valsalva Maneuver / Q000502:physiology*; D014648:Varicose Veins / Q000235:genetics / Q000503:physiopathology; D014680:Veins / Q000033:anatomy & histology* / Q000000981:diagnostic imaging / Q000502:physiology*