BLOOD RHEOLOGY AND RENAL TRANSPLANTATION: AN INTRIGUING RELATIONSHIP FOR ASSESSING CARDIOVASCULAR RISK

COMPLICATIONS - CARDIOVASCULAR

E. Bertoni¹, M. Salvadori¹, M. Zanazzi¹, C. Fatini², E. Sticchi², A. Liotta², I. Ricci², L. Mannini², R. Abbate^2
1Renal Unit, Careggi University Hospital, Florence/ITALY, ²Thrombosis Center, University of Florence, Florence/ITALY

Body: Introduction Clinical studies provided evidence that abnormalities in blood flow properties may contribute to cardiovascular events and an altered hemorheological profile, which worsed microcirculatory blood flow and influences vascular disease, might determine both cardiovascular complications and progression of renal failure in renal transplant recipients (RTRs). Few data are available confirming the impact of blood rheology in affecting cardiovascular risk in RTRs. We performed this study in order to investigate the rheological status in RTR patients at least 12 months post-transplant with stable and normal renal function. Methods We investigated 239 RTR patients at least 12 months post-transplant with stable and normal renal function [156 men, median age 53 (17-75) yrs, 83 women, median age 50 (17-74) yrs] compared with 90 control well matched subjects, with no history of renal or cardiovascular disease. Hemorheologic profile was performed by assessing both whole-blood viscosity (WBV) (at shear rates of 0.512 and 94.5 s^-1 ), plasma viscosity, erythrocyte deformability and aggregability, and coagulation parameters (hemoglobin, hematocrit and fibrinogen concentrations). Results Hemorheological and hematological parameters of the study population are reported in table. In RTRs a significantly higher hematocrit-adjusted, but not native, whole blood viscosity was found (p<0.0001). Moreover plasma viscosity and red blood cell deformability were significantly different between patients and controls (p<0.0001), whereas no difference in erythrocyte aggregation between patients and controls was observed (p=0.5). Fibrinogen, but not hematocrit, significantly increased in RTRs (p=0.001). Significantly lower hemoglobin values were observed in RTRs than in controls (p<0.0001).

Variables	RTRs	Controls	p
WBV at 0.512 s-1 (mPa*s)	20.4 (12.0-43.7)	20.5 (13.4-29.4)	0.2
Hematocrit-adjusted WBV at 0.512 s-1 (mPa*s)	23.5 (10.6-68.5)	19.9 (13.3-27.0)	<0.0001
WBV at 94.5 s-1 (mPa*s)	4.1 (3.0-6.7)	4.1 (3.6-5.3)	0.4
Hematocrit-adjusted WBV at 94.5 s-1 (mPa*s)	4.5 (3.2-8.4)	4.1 (3.3-5.2)	<0.0001
Plasma viscosity (mPa*s)	1.39 (1.13-1.90)	1.35 (1.21-1.58)	<0.0001
Erythrocyte deformability index	6.4 (1.7-19.9)	11.5 (9.0-18.0)	<0.0001
Erythrocyte aggregation index	3.0 (1.4-6.4)	2.9 (1.4-4.8)	0.5
Hematocrit (%)	40.4 (30.3-52.5)	42.0 (36.8-49.1)	0.003
Hemoglobin (g/L)	12.9 (9.9-16.9)	14.2 (11.8-16.9)	<0.0001
Fibrinogen (mg/dL)	379 (204-914)	330 (227-497)	0.001
Total cholesterol (mg/dL)	214 (115-345)	200 (115-281)	0.01
Triglycerides (mg/dL)	162 (50-545)	86 (29-322)	<0.001

Conclusions This study provides evidence of an altered hemorheological profile in RTRs in comparison to that observed in health population. In particular, we observed a significantdifference in hematocrit-adjusted whole blood viscosity and in both plasma viscosity and erytrhrocyte deformability, known to influence blood rheology. Traditional risk factors, such as hypertension,smoking habit, diabetes, and dyslipidemia are well known to increase the risk of cardiovascular disease in RTRs, thus possibly predict the incidence of cardiovascular events. Accordingly, an alteredrheological profile, which is known to influence cardiovascular risk, may contribute to implement the risk profile panel in RTRs.Our findings may suggest a contribution in assessing cardiovascularrisk in RTRs in order to prevent cardiovascular complications, indeed a tailored pharmacological intervention, aimed to correct the rheological milieu, might permit to reduce cardiovascular risk inthese patients.

Disclosure: All authors have declared no conflicts of interest.