Doppler ultrasound and calcification score: improving vascular access surveillance.
OBJECTIVE
Vascular access (VA) dysfunction limits hemodialysis delivery, which increases morbidity and mortality. The most com mon cause of VA failure is thrombosis, due to flow limiting stenosis resulting from neointimal hyperplasia. This occurs not only due to hemodynamic factors but also by systemic ones related to vascular atherosclerosis, inflammation and calcification, which has developed a simple vascular calcification score (SVCS) predictor of vascular calcification and arterial stiffness. The NKF-K/DOQ recommends several diagnostic procedures for VA surveillance. Blood access flow (Qa) has predictive power for the detection of stenosis. Our aim was to evaluate the role of systemic factors, especially SCVS, on Qa.


METHODS
Transversal study in 50 patients. Qa value was obtained with Blood Temperature Monitor and Doppler method. Pearson coefficient evaluated correlation between them. Clinical, lab and radiological variables were recorded and non-parametric tests evaluated how both Qa varied with them.


RESULTS
Pearson's corelation between DU-Qa and TD-Qa was 0.851 (p-value <0.001). DU-Qa varied significantly with age (p = 0.012), VA type (p = 0.021), SCVS (p = 0.030), intra-access arterial pressure (p = 0.015) and time on dialysis (p = 0.002). BTM-Qa varied significantly with diabetes status (p = 0.027), age (p = 0.017), first VA status (p = 0.036), intra-access arterial pressure (p = 0.028) and dialysis time (p = 0.001). Nevertheless, gender, hypertensive status and analitical parameters did not change the flow values.


CONCLUSIONS
Higher SVCS was associated only with lower DU-Qas, giving this method an advantage towards the indirect one. Additionally, a simple method like SVCS may be used to guide new surveillance recommendations accordingly to risk stratification.
a Vascular Access Center of Nephrocare Coimbra , Coimbra , Portugal .
Maria
M
Guedes Marques
a Vascular Access Center of Nephrocare Coimbra , Coimbra , Portugal .
Carlos
C
Botelho
a Vascular Access Center of Nephrocare Coimbra , Coimbra , Portugal .
Pedro
P
Maia
b Department of Nephrology , University Hospital Parc Tauli of Sabadell , Barcelona , Spain , and.
José
J
Ibeas
c Vascular Access Center of Nephrocare Lisboa , Lisbon , Portugal.
Pedro
P
Ponce
D000368:Aged; D001783:Blood Flow Velocity; D001794:Blood Pressure; D002114:Calcinosis / Q000000981:diagnostic imaging*; D003251:Constriction, Pathologic / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012039:Regional Blood Flow; D013927:Thrombosis / Q000000981:diagnostic imaging*; D018608:Ultrasonography, Doppler; D014654:Vascular Patency
Calcification; Doppler ultrasound; neointimal hyperplasia; stenosis; surveillance; vascular access