Year : 1998 | Volume
: 9 | Issue : 1 | Page : 8--11
Doppler Ultrasound Evaluation of Hemodialysis Vascular Access
Danlami Z Taminu1, Sameer O Huraib1, Waldemar Gorka2, Saleh Abu Romeh1, Khaja M.quadric1, Sad Al Turki3, Aamir Iqbal1, Ahmed Flaiw1,
1 Nephrology Unit, King Fahad National Guard Hospital, Riyadh, Saudi Arabia
2 Department of Medical Imaging, King Fahad National Guard Hospital, Riyadh, Saudi Arabia
3 Department of Vascular Surgery, King Fahad National Guard Hospital, Riyadh, Saudi Arabia
Sameer O Huraib
Division of Nephrology & Hypertension, King Fahad National Guard Hospital, P.O. Box 22490, Riyadh 11426
Brescia-Cimino arteriovenous fistulas (AVF) ad synthetic grafts are the usual forms of vascular accesses for hemodialysis. Although angiography has been the traditional means of imaging these vascular systems, colour Doppler flow imaging (CDFI) offers a non-invasive method of evaluating AVF dysfunction. We retrospectively evaluated 22 patients with clinical evidence of access dysfunction who were studied by CDFI and of whom 14 also underwent angiography. We analyzed the results of whom the 14 patients who had both CDFI and angiography as angiography was impossible in the remaining eight patients due to difficulty with cannulation. Eight patient had thrombosis on CDFI and angiopraphy in all eight patients confirmed these findings. CDFI showed six stenoses, all of which were proven on angiopraphy. Overall,, CDFI correctly identified all lesions that were seen angiographically ginging a sensitivity and specifificity of 100%. Moreover, CDFI detected two cases of pseudoaneurysms which were missed by angiography. CDFI provides an adequate means of evaluating AVF dysfunction and should be the initial imaging technique of choice.
|How to cite this article:|
Taminu DZ, Huraib SO, Gorka W, Romeh SA, M.quadric K, Al Turki S, Iqbal A, Flaiw A. Doppler Ultrasound Evaluation of Hemodialysis Vascular Access.Saudi J Kidney Dis Transpl 1998;9:8-11
|How to cite this URL:|
Taminu DZ, Huraib SO, Gorka W, Romeh SA, M.quadric K, Al Turki S, Iqbal A, Flaiw A. Doppler Ultrasound Evaluation of Hemodialysis Vascular Access. Saudi J Kidney Dis Transpl [serial online] 1998 [cited 2021 Aug 1 ];9:8-11
Available from: https://www.sjkdt.org/text.asp?1998/9/1/8/39294
A well functioning vascular access is a prerequisite for chronic hemodialysis treatment. Arteriovenous fistula (AVF) of the Brescia-Cimino type is the vascular access most often used  . One fourth of all admissions of hemodialysis patients are attributable to vascular access placement and complications  .
Impaired arerial flow or high venous pressure during dialysis can be the result of AVF stenosis, thrombosis, aneurysms or infections  . Angiopraphy has been the accepted gold standard for evaluation of the integrity of hemodialysis AV fistulas and grafts  . Moe recently however, colour Doppler flow imaging (CDFI) has been investigated as a non-invasive means of evaluating hemodialysis access complications ,, .
In this study the diagnostic value of CDFI was investigated in a population of dialysis patients with clinically presumed dysfunction or complication of their vascular access
Twenty-two patients at the King Fahad National Guard Hospital dialysis unit were recruited. These patients had clinical evidence of access dysfunction (elevated venous pressure, increased recirculation, low arterial blood flow and impaired shunt bruit or thrill). Ten males and 12 females on chronic on chronic hemodialysis were evaluated. Their ages ranged between 26 and 79 years (mean ages 58 years). Duration of fistula placement ranged from 4 to 72 months (mean 23 months). CDFI examination was performed using commercially available sonographic equipment (Acuson 128 XP, Mountain View CA) with a 7.5 MHZ limeararray tranducer. The vascular access was assessed from the arterial anastomosis, through the entire access and into the draining veins. All fistulas were analyzed in both transverse and longitudinal planes. Spectral waveforms were obtained at each level. Sonograms were interpreted by one of the authors (W.G.) without knowledge of the angiographic results. CDFI studies were conducted before angiography. Thrombosis was defined as a hypoechoic or echogenic filling defect obstructing partially or completely the vascular lumen [Figure 1]. If manual compression changed the shape of the obstructive material, thrombus was called acute. Fistula stenosis was diagnosed with. Doppler ultrasound (US) when focal area of high velocity (aliasing) was present and the sampled velocity jet exceeded 4 times the reference velocity in the prestenotic segment. Focal increase of systolic velocities of greater then 3 m/s and diastolic of greater than 1 m/s was recorded in all cases of hemodynamically significant stenosis. [Figure 2]. With 16-gauge dialysis needles in position prior to hemodialysis, 14 patients were transferred to te radiology department. Using digital subtraction angiography technique contrast was injected in the fistula needle, and the vasculature was visualized to two planes from the AVF or graft to the superior vena cava.
All the 22 patients had abnormal finding on CDFI. Only 14 patients however, had angiopraphy. The remaining 8 patients did not have angiography due to severe thrombosis making cannulation difficult. Therefore, we analysed only the 14 patients who had completed the study.
[Table 1] show that six stenosis were identified angiographically in native AVF. CDFI also showed stenosis in all the six patients for a sensitivity and specificity of 100%. Out of the six patients with stenosis, three had successful angioplasty, while in the remaining three patients, anew AVF was create as the lesions were not amenable to surgical correction [Table 2].
Six patients with native AVF had thrombosisi on CDFI, which were also confirmed on DCFI, which were also confirmed on angiopraphy [Table 1]. The sensitivity and specificity of DCFI for detection of thrombosis was therefore 100%. None of these six patients had associated stenosis. In two patients with gortex graft, thrombosis was demonstrated on CDFI. These were confirmed angiographically. Of the eight patients with thrombosis, seven had successful thrombectomy and one patient had an new AVF [Table 2].
Two cases of pseudoaneurysm with intramural thrombus (confirmed at surgery) were identified by CDFI, but none was visualized on angiography. Other lesions (which were demonstrated by both CDFI and angiography) included two subclavian vein thrombosis, two collateral circulations and one axillary vein thrombosis. Completed correlation between the angiographic examination and CDFI was obtained in all 12 patients with native AVF. In the remaining two patients with gortex graft, complete correlation was also demonstrated.
Properly functioning vascular access is an absolute requirement for long term hemodialysis treatment  . AVF dysfunction could result from a spectrum of vascular lesions. It is usually preceded by poor arterial flow, high venous pressure, increases recirculation, clot withdrawal or difficulty with vessel cannulation  .
Angiography has been the traditional gold standard for investigating fistula dysfunction  . However, It is invasive, with a potential for fistula injury and discomfort to patients , . In addition, in patients with total or near complete fistula occlusion due to thrombosis, puncture of the vessel may be difficult or impossible as in some of our cases. Furthermore, pseudoaneurysms and perivascular abnormalities such as hematoma or abscess cannot be determined by angiogrpahy.
In recent years non-invasive methods have become available for the investigation or AVF dysfunction. Colour Doppler flow imaging of vascular access has proven effective in evaluation both anatomic vascular features and blood flow parameters , . Middleton et al  found that Doppler sonography correctly identified 20 of 23 stenosis, the majority of occluded or thrombosed vessels and 18 of 19 pseudoaneurysms. These investigators concluded that Doppler sonography was an adequate means of imaging suspected complications of hemodialysis vascular access. Nonnast-Daniel et al  have confirmed the utility of the method in detecting stenosis by angiography or surgery. In addition these investigators suggested that study of thrombosed fistulas by CDFI might proved evidence of an underlying stenosis that might be of value prior to surgical thrombectomy.
The result so our study suggests that CDFI is an adequate means of imaging vascular access for dialysis. Furthermore, comparison of CDFI with angiography shows a correlation with angiographic techniques.
In comparison with angiography , , the advantages of sonography are it is inexpensive, non-invasive, painless, requires no contrast medium, can be used repetitively, detects occlusive thrombus, pseudoaneurysms and perivascualr lesions, can assess both the caliber and length of stenotic segments and can be used as an accurate guide for angioplasty. Furthermore, data on a prospective basis may enlighten us more on the value of this method as a screening tool pending which CDFI is suggested as the initial imaging technique in hemodialysis patients with vascular access dysfunction.
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