Optimal Screening Program in Detecting Stenosis and Predicting Thrombosis in Hemodialysis Graft

NCT03839264 | Completed DMC

• 1 other identifier: AOVerona
• Study Type: observational
• Target: 48
• Locations: 1 country
• Sites: 1

Brief Summary

A well-functioning vascular access is essential for providing adequate life-sustaining treatment in patients with end stage renal disease on maintenance hemodialysis. The preferred long-term vascular access is the arteriovenous fistula (AVF), which is created using the vessels of the patient by surgically connecting an artery with a superficial vein to increase the blood flow (Qa) in the venous system, which will dilate allowing the insertion of two needles, one to carry the blood to the dialyzer, and the other to return the cleansed blood to the body with the aid of a dialysis machine. Unfortunately, the high prevalence of vascular disease of the hemodialysis patients make difficult to create an adequate AVF in as many as 20 to 60% of the patients.In these persons, a valid alternative is the arteriovenous graft: in graft method an artery is surgically connected to a vein with a short piece of synthetic soft tube which is implanted under the skin. Needles are inserted in the graft during the dialysis treatment. Compared to an AV, however, graft is at higher risk of complications. The most frequent complication is thrombosis (i.e. the formation of blood clot inside the graft). Usually, thrombosis is the consequence of an underlying significant stenosis (i.e. a greater than 50% narrowing of the vessel or graft lumen by comparison with the lumen of a normal adjacent vessel or graft) and its hemodynamic consequences of decreasing the access blood flow (Qa) and/or increasing pressure within the graft. Therefore, all vascular access guidelines recommend regular noninvasive screening programs of grafts for timely identification of a stenosis associated with some type of functional or hemodynamic impairment, because its repair may prevent thrombosis and lengthen the useful life of the access. Screening methods include clinical monitoring and surveillance, which uses special equipment either to assess the hemodynamic consequences of stenosis by measuring Qa and static venous intra-access pressure ratio (VAPR) or to visualize the stenosis by means of duplex ultrasound (DU). Guidelines also state that there is insufficient evidence to prefer one method to another due to the lack of adequate comparative studies. The purpose of our study is to identify an optimal screening program for stenosis detection and elective repair by comparing the diagnostic performance for stenosis and incipient thrombosis of all the available screening tools in the same graft population

Conditions

Arteriovenous Graft Stenosis; Arteriovenous Graft Thrombosis

Keywords

diagnostic accuracy; screening

Outcome Measures

Primary Outcomes (9)

• Presence of a significant stenosis at DSA (yes/not)

  presence of a greater than 50% reduction in the vessel or graft lumen diameter by comparison with the lumen diameter of a normal adjacent vessel or graft in mm/mm.

  1 hour

• Presence of significant stenosis at DU (yes/not)

  presence of a greater than 50% reduction in the vessel or graft lumen diameter by comparison with the lumen diameter of a normal adjacent vessel or graft in mm/mm and/or a peak systolic velocity \> 400 cm/sec at the stenotic site

  30 minutes

• Abnormal clinical monitoring (yes/not)

  signs of graft dysfunction noted during dialysis: difficult cannulation, aspiration of clots, inability to achieve the prescribed dialysis pump blood flow (Qb), excessive post-dialysis bleeding or a \>0.3 drop in single pool dialysis dose

  15 minutes

• Qa measured by ultrasound dilution: QaU (ml/min)

  Qa was measured by the Ultrasound dilution method during dialysis using the Transonic HD03 device, in the same dialysis session in which pressures were measured: each value is the mean of triplicate measurement

  15 minutes

• Qa measured by DU: QaD (ml/min)

  Measurement of Qa is made in a straight portion of the brachial artery in the mid-third of the upper arm. The diameter of the blood flow was measured directly on the vessel thanks to b-flow color technology. Sampling volume was placed in the centre of the lumen and in the longitudinal plane. Typically, measurements were obtained over a sequence of 3 to 5 cardiac cycles (to allow for time-averaged mean velocities, TAV). TAV was calculated directly by the device from a doppler spectral waveform by the duplex scanner system. The Qa (in ml/min) is calculated by the device as the product of the artery diameter and the TAV. The mean value of at least 3 separate measurements was reported.

  10 minutes

• Dynamic arterial pressure / dialysis pump blood flow: dAP/Qb (mmHg/ml/min)

  Dynamic arterial pressure (dAP) was measured in the initial 5 minutes of dialysis and detected by the dialysis machine using the pressure sensor connected with the "arterial" needle and expressed as the ratio with dialysis blood pump flow Qb.

  5 minutes

• dynamic venous pressure: dVP (mmHg)

  Dynamic venous pressure (dVP) was measured in the initial 5 minutes of dialysis and detected by the dialysis machine using the pressure sensor connected with the "venous" needle

  5 minutes

• Derived static venous pressure ratio: VAPR (mmHg/mmHg)

  obtained in the initial 5 minutes of dialysis by the dVP, Qb, haematocrit and systemic systolic and diastolic blood pressure values, according to literature in mmHg/mmHg

  10 minutes

• occurrence of symptomatic acute hypotension during the follow up (yes/not)

  during the follow up an episode of acute symptomatic hypotension in the intra- and inter-dialytic interval was recorded. Hypotension was defined as a sudden fall of systemic blood pressure associated with one or more of fainting palpitation, nausea, blurred vision, feeling weak or cold

  4 months

Secondary Outcomes (4)

• correlation coefficient (r) between QaU and QaD measurements (ml/min / ml/mn)

  30 minutes

• Concordance for the presence of significant stenosis between two radiologists (yes/not)

  1 hour

• intra-assay coefficient of variation of QaU and QaD (%)

  15 minutes

• inter-assay coefficient of variation of QaU, dAP/Qb,dVP and VAPR (%)

  1 month

Study Arms (1)

Graft stenosis and thrombosis

Diagnostic performance for stenosis at angiography of non invasive screening tools (duplex ultrasound, access blood flow (Qa), dynamic and static dialysis machine venous pressures, dynamic dialysis machine arterial pressure, and monitoring) and incipient thrombosis (within 4-month period) of the presence and degree of stenosis at angiography, non invasive screening techniques and acute hypotensive episode/s during the follow-up

Diagnostic Test: Graft stenosis and thrombosis

Interventions

Graft stenosis and thrombosis DIAGNOSTIC_TEST

Graft stenosis and thrombosis

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Haemodialysis patients with an AV graft as vascular access

You may qualify if:

• All the patients with a polytetrafluroethylene (PTFE) graft as haemodialysis vascular access who were treated at the haemodialysis Unit of the Polyclinic of B.go Roma Hospital in Verona during the recruitment period and who agreed to take part at the study

You may not qualify if:

• No one.

Sponsors & Collaborators

• Azienda Ospedaliera Universitaria Integrata Verona: lead

Study Sites (1)

Azienda Ospedaliera Integrata di Verona - Policlinico Borgo Roma

Verona, 37135, Italy

Location

Related Publications (8)

• Vascular Access 2006 Work Group. Clinical practice guidelines for vascular access. Am J Kidney Dis. 2006 Jul;48 Suppl 1:S176-247. doi: 10.1053/j.ajkd.2006.04.029. No abstract available.

  PMID: 16813989 BACKGROUND

• Tordoir J, Canaud B, Haage P, Konner K, Basci A, Fouque D, Kooman J, Martin-Malo A, Pedrini L, Pizzarelli F, Tattersall J, Vennegoor M, Wanner C, ter Wee P, Vanholder R. EBPG on Vascular Access. Nephrol Dial Transplant. 2007 May;22 Suppl 2:ii88-117. doi: 10.1093/ndt/gfm021. No abstract available.

  PMID: 17507428 BACKGROUND

• Polkinghorne K; Caring for Australians with Renal Impairment (CARI). The CARI guidelines. Vascular access surveillance. Nephrology (Carlton). 2008 Jul;13 Suppl 2:S1-11. doi: 10.1111/j.1440-1797.2008.00992.x. No abstract available.

  PMID: 18713118 BACKGROUND

• Tessitore N, Bedogna V, Verlato G, Poli A. Clinical access assessment. J Vasc Access. 2014;15 Suppl 7:S20-7. doi: 10.5301/jva.5000242. Epub 2014 Apr 12.

  PMID: 24817450 BACKGROUND

• Frinak S, Zasuwa G, Dunfee T, Besarab A, Yee J. Dynamic venous access pressure ratio test for hemodialysis access monitoring. Am J Kidney Dis. 2002 Oct;40(4):760-8. doi: 10.1053/ajkd.2002.35687.

  PMID: 12324911 BACKGROUND

• Krivitski NM. Theory and validation of access flow measurement by dilution technique during hemodialysis. Kidney Int. 1995 Jul;48(1):244-50. doi: 10.1038/ki.1995.290.

  PMID: 7564085 BACKGROUND

• Tessitore N, Bedogna V, Verlato G, Poli A. The rise and fall of access blood flow surveillance in arteriovenous fistulas. Semin Dial. 2014 Mar;27(2):108-18. doi: 10.1111/sdi.12187. Epub 2014 Feb 5.

  PMID: 24494667 BACKGROUND

• Tessitore N, Bedogna V, Melilli E, Millardi D, Mansueto G, Lipari G, Mantovani W, Baggio E, Poli A, Lupo A. In search of an optimal bedside screening program for arteriovenous fistula stenosis. Clin J Am Soc Nephrol. 2011 Apr;6(4):819-26. doi: 10.2215/CJN.06220710. Epub 2011 Mar 31.

  PMID: 21454718 BACKGROUND

MeSH Terms

Interventions

Blood Coagulation

Intervention Hierarchy (Ancestors)

Hemostasis; Blood Physiological Phenomena; Circulatory and Respiratory Physiological Phenomena

Study Officials

• Nicola Tessitore, MD

  AO Verona

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: OTHER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: June 29, 2017
• First Posted: February 15, 2019
• Study Start: August 1, 2011
• Primary Completion: May 30, 2018
• Study Completion: September 30, 2018
• Last Updated: February 15, 2019

Record last verified: 2019-01

Data Sharing

• IPD Sharing: Will share
• Time Frame: one year from february 1st 2019

Locations

IT (1)