Impact of sleeve gastrectomy on red blood cell aggregation: a 12-month follow-up study

To investigate the effects of weight loss due to laparoscopic sleeve gastrectomy (LSG) on erythrocyte aggregation and the relationship of anthropometric and plasmatic factors, such as plasma viscosity, fibrinogen and lipids, with erythrocyte aggregation.

The RBC aggregation and kinetics of the red blood cell aggregation were performed by the Laser-assisted Optical Rotational Cell Analyser (LORCA). Before the LSG and 6 and 12 months after the LSG, we evaluated the aggregation index (AI), amplitude (AMP) and aggregation half-time (t1/2), plasma viscosity, fibrinogen, glucose and lipids patterns in 15 non-diabetic obese subjects.

The static and kinetic parameters of aggregation in obese patients at each time point after bariatric weight loss surgery were calculated and significant differences were observed at 12 months after surgery. AI and AMP decreased from 69.81±5.12% and 27.43±2.9 a.u. at baseline to 64.91±5.94% and 22.15±4.3 a.u. 12 months after surgery, respectively. The t1/2 increased from 1.7 (1.32-2.24) s at baseline compared with 2.02 (1.68-2.42) s at 12 months after the surgery. Plasma viscosity and fibrinogen decreased from 1.50±0.093 mPa s and 3.0±0.41 g l(-1) at baseline to 1.407±0.062 mPa s and to 2.66±0.25 g l(-1) 12 months after surgery, respectively. AI correlated positively with BMI (r=0.74, P=0.001), waist circumference (r=0.68, P=0.005), fibrinogen (r=0.52, P=0.045) and plasma viscosity (r=0.76, P=0.001) and negatively with percentages of weight lost after surgery (r=-0.54, P=0.034). Multivariate analyses found that the BMI, fibrinogen and plasma viscosity independently influenced the AI.

The study demonstrated that weight loss due to restrictive bariatric surgery can beneficially affect red cell aggregation parameters. The improvement of the RBC aggregation behaviours among obese subjects with weight loss due to LSG was associated with changes in plasmatic factors, especially fibrinogen.