Features of Formation of Permanent Vascular Access in Patients on Programmatic Hemodialysis

The research is dedicated to developing optimal approaches to the formation of permanent vascular access in patients with terminal chronic kidney failure undergoing programmatic hemodialysis. The study examines methods of vascular access formation, its complications, and the influence of volume blood flow on the cardiovascular system. Special attention is given to the application of ultrasonic examination methods for selecting the optimal type and location of vascular access and for dynamic monitoring of its condition after surgery.

Relevance of the problem. The number of patients suffering from terminal chronic kidney failure (TCKF) requiring hemodialysis treatment is increasing annually worldwide. According to the registry of the Russian Dialysis Society, as of 2005, 11,864 patients were on programmatic hemodialysis (PHD) in Russia. The annual increase in patients on programmatic hemodialysis averages 10.5% (Bibkov B.T., Tomilina N.A., 2007). Successful long-term treatment of these patients by means of programmatic hemodialysis depends to a greater extent on solving problems associated with the formation of adequate vascular access. Currently, the requirements imposed on permanent vascular access (PVA) are being viewed in a new aspect. This is due to the increase in the lifespan of patients on chronic hemodialysis as a result of improved quality, as well as the growing number of elderly patients and individuals suffering from diabetes mellitus, polycystic kidney disease (Mukhametzyanos I.Sh., 2001). This predetermines the difficulties of optimal choice in forming permanent vascular access in each specific situation. Currently, both in the USA and in Europe, the survival rate of patients with diabetic nephropathy on dialysis has substantially increased, but it remains 20-30% worse than in patients with TCKF of other etiology. Today, diabetes is by no means considered a contraindication to hemodialysis treatment (Stetsiuk E.A., Petrov S.I., Tretyakov B.V., 2001).

The ideal vascular access is recognized as one that ensures correspondence of blood flow speed to the prescribed dialysis dose, functions for a long time (many years), and has no complications. In the literature, the most acute questions concern the choice of type of PVA and the tactics of its complications. Currently, two approaches to the priority choice of primary PVA exist in various hemodialysis centers worldwide: creation of a native AVF or the use of a synthetic vascular prosthesis (SVP) for this purpose (NKF-DOQI, 1997). In most European clinics, the method of choice is recognized as the formation of a native AVF, most often in the Brescia-Cimino variant (Brescia M.J., Cimino J.E., Appel K., Hurwick B.J., 1966; Ezzahiri R., Lemson M.S., Kitslaar P.J. et al., 1999; Oncevslci A., Dejanov P., Gerasimovslca V. et al., 2000). The use of SVP has gained the greatest prevalence in the USA, where their share in the structure of all PVAs ranges from 37 to 75% (Besarab A., Adams M., Amatucci S. et al., 2000; Hirsch D.J., Jindal K.K., Schaubel D.L., Fenton S.S., 1999; Nassar G.M., Ayus J.C., 2001). In recent years, a clear trend toward limiting indications for the use of SVP has been noted. This is explained by the statistically reliably shorter duration of SVP functioning and a greater number of required corrective procedures (thrombectomy and angioplasty) in the early and late postoperative period compared to native AVFs (Ascher E., Hingoran A., Gundus Y. et al., 2001; Astor B.C., Coresh J., Powe N.R. et al., 2000; Gradman W.S., Cohen W., Haji-Aghaii M., 2001). Thus, in one of the European centers, problems with arteriovenous fistulas arose in 69% of cases, but by the time of fistula maturation, 83% of these problems were resolved independently (McLafferty R.B., Pryor R.W., Jonson C.M. et al., 2007).

Based on these facts, the overwhelming majority of researchers consider the formation of a native AVF the method of choice for PVA, including in elderly patients and those suffering from diabetes mellitus, provided that adequate superficial veins of the upper extremity are present (Allon M., Ornt D.B., Schwab S.J. et al., 2000; Konner K., 2001; Miller P.E., Carlton D., Deierhoi M.H. et al., 2000).

A strategic direction ensuring improved PVA survival, proposed by the majority of hemodialysis centers, is not the formation of a new vascular access but ensuring the longest possible function of the existing one through timely diagnosis of complications, percutaneous intervention and angioplasty, as well as surgical methods (Becker B.N., Breiterman-White R., Nylander W. et al., 1997; Murphi G.J., White S.A., Nicholson M.L., 2000).

After summarizing all available data, the NKF-DOQI working group (1997) on vascular access problems concluded that the quality of life of hemodialysis patients and overall treatment outcomes can be significantly improved if the number of formed native AVFs increases and access dysfunction is recognized before its thrombosis. To this end, significant attention is devoted to research on PVA blood flow characteristics using angiography, Doppler sonography, thermodilution, determination of venous resistance and recirculation (Lindsay R.M., Leypoldt J.K., 1999; Paun M., Beach K., Ahmad S. et al., 2000; Schwab S.J., Oliver M.J., Su-hocki P., McCann R., 2001). It has been proven that prospective control and correction of hemodynamically significant PVA stenosis contribute to improved its function and reduced number of thromboses (Lumsden A.B. et al., 1997; NKF-DOQI, 1997).

In the available literature, the number of publications on the influence of the speed of volume blood flow through the formed PVA on the right heart chambers with the development of right ventricular insufficiency in patients on PVA is very small. Moreover, author opinions are contradictory (Yenkina T.N., Lukichev B.G., Yenkin A.A., Grinev K.M., 1999; Komarova E.D., Karlova N.A., Komadenko M.S., Voron E.A., 2004; Iwaschima Y., Horio T., Takami Y. et al., 2002).

Currently, no known type of PVA is ideal. Therefore, the relevance of a new comprehensive approach to creating an adequate long-term vascular access in patients with TCKF on programmatic hemodialysis (PHD) persists (Moisyuk Ya.G., Belyaev A.Yu., 2004).

The goal of the research is the development of optimal approaches to the formation of permanent vascular access in patients with terminal chronic kidney failure on programmatic hemodialysis.

Research tasks:

1. Conduct a clinical analysis of formed permanent vascular accesses and their complications in patients with terminal chronic kidney failure on programmatic hemodialysis depending on its cause without preliminary instrumental examination of vessels.

2. Assess the condition of permanent vascular accesses in patients with terminal chronic kidney failure on programmatic hemodialysis using preoperative and postoperative ultrasound methods of examination.

3. Study the dynamics of volume blood flow speed through the permanent vascular access and its influence on echocardiographic sizes of the right ventricle of the heart in patients on programmatic hemodialysis.

4. Create an algorithm for preoperative vessel examination and permanent vascular access in dynamics in patients on programmatic hemodialysis for the purpose of its long-term functioning.

Scientific novelty. For the first time, multi-level ultrasound examination of vessels with determination of diameter and volume blood flow speed in patients on programmatic hemodialysis before and after formation of the arteriovenous fistula has been applied.

Criteria for choosing adequate permanent vascular access have been determined.

The advantages of determining volume blood flow speed at the level of the middle third of the brachial artery in the operated extremity have been established.

An algorithm for preoperative vessel examination and postoperative dynamic monitoring of permanent vascular access has been developed.

It has been proven that the magnitude of volume blood flow through the permanent vascular access substantially does not influence the echocardiographic sizes of the right ventricle of the heart regardless of the level of the arteriovenous fistula.

Practical significance. The results of the research determine approaches to solving problems associated with the formation of permanent vascular access in patients with different causes of terminal chronic kidney failure on programmatic hemodialysis.

It has been established that the created algorithm of preoperative vessel examination significantly reduces the share of primary vascular access failure, decreases the number of its complications, and extends its cumulative survival to 1 year from 72.3% to 95.2%; to 2 years from 61.2% to 86.9%; to 3 years from 50.4% to 74.6%.

It has been revealed that postoperative ultrasound control of the permanent vascular access in dynamics at different time intervals allows timely prediction and detection of its late complications.

Validation of the work. The main provisions of the dissertation were reported and discussed at: the Republican Scientific and Practical Conference "Actual Questions of Urology, Nephrology and Replacement Kidney Therapy" (Bugulma, 1999), the Nth Conference of the Russian Dialysis Society (St. Petersburg, 2001), the 1st Joint Congress "Actual Problems of Extracorporeal Blood Cleansing, Nephrology and Hemapheresis" (Moscow, 2002), the X All-Russian Congress of Cardiovascular Surgeons "Cardiovascular Diseases" (Moscow, 2004), the X All-Russian Conference "Young Scientists in Medicine" (Kazan, 2005), the X All-Russian Conference of Young Scientists (Moscow, 2006), the XI All-Russian Scientific and Practical Conference "Young Scientists in Medicine" (Kazan, 2006).

Implementation of the research results. The results of the research have been implemented in the practical activities of the hemodialysis department of City Clinical Hospital No. 6 of Kazan and the department of extracorporeal detoxification of the Children's Republican Clinical Hospital of the Ministry of Health of the RT, and are also used in the educational process at the Department of Surgical Diseases No. 2 of the State Educational Institution of Higher Professional Education "Kazan State Medical University FAPO".

Publications. Based on the dissertation materials, 14 printed works have been published.

Propositions to be defended:

1. Assessment of the condition of vessels by means of ultrasound diagnostics in the preoperative period allows the correct choice of type, variant, and location of permanent vascular access formation.

2. Postoperative dynamic control of the permanent vascular access by means of color duplex scanning timely predicts the development of complications and determines the paths of optimal conservative or surgical correction, ensuring its long-term functioning.

3. The speed of volume blood flow through the permanent vascular access should preferably be determined at the level of the middle third of the brachial artery of the operated extremity.

4. Echocardiographic sizes of the right ventricle of the heart reliably do not correlate with the speed of volume blood flow through the permanent vascular access of any location.