Correlation of physiological, biochemical and morphological parameters and outcomes of native arteriovenous fistulas for hemodialysis

Preduslov za uspešnu hemodijalizu (HD) je postojanje adekvatnog vaskularog pristupa sistemskoj cirkulaciji koji omogućava dovoljan dotok krvi u vantelesnom sistemu. Nativna podlaktična radiocefalična arteriovenska fistula (RCAVF) je preferirani i željeni vaskularni pristup za hemodijalizu od strane vaskularnih hirurga i nefrologa. Međutim, visoki procenat neuspeha maturacije je barijera koju treba prevazići. Mnoge studije su ispitivale faktore povezane sa neuspehom maturacije AVF. Starost, ženski pol, dijabetes, rasa, prisustvo cerebrovaskularne ili periferne vaskularne bolesti su samo neki od prediktivnih faktora za neuspeh AVF. Međutim, optimalni dijameter krvnih sudova za kreiranje AVF ostaje i dalje ključno pitanje. Pored dijametra, neki funkcioni-fiziološki parametri izgleda da imaju dodatnu ulogu u maturaciji AVF. Ultrazvuk kao neinvazivna metoda nam može dati značajnu informaciju o morfološkim i funkcionim parametrima krvih sudova kao i o spremnosti za korišćenje AVF. Vreme od momenta kreiranja AVF do prve punkcije se zove period maturacije. Postoje razlike u mišljenju vezano za vreme prve kanulacije. Optimalno vreme je kada je process maturacije završen, a to znači da je pristup spreman za korišćenje, da može da obezbedi adekvatnu dozu dijalize (Kt/V) sa minimalnim rizikom od oštećenja. Zbog svega navedenog, cilj ovog istraživanja je bio da se ispita korelacija različitih faktora (morfoloskih, funkcionih i biohemijskih) i ishoda nativnih AVF za hemodijalizu; da se definišu faktori od najvećeg uticaja kao i da se na osnovu dobijenih rezultata predloži klinički algoritam predikcije ishoda nativnih podlaktičnih AVF. Ispitivanje je obuhvatilo 122 uzastopna bolesnika u terminalnoj fazi hronične bubrežne slabosti koji su započeli HD u periodu od Oktobra 2008 do Aprila 2010. godine. Svi bolesnici su bili hospitalizovani u Klinici za nefrologiju, Kliničkog centra Srbije radi kreiranja primarne AVF i započinjanja hroničnog programa hemodijalize. Svi bolesnici su bili informisani o procedure planiranih ispitivanja za koja su dali svoju saglasnost. Studija je odobrena od strane Etičkog komiteta Kliničkog centra Srbije. Svim bolesnicima je preoperativno obavljen fizikalni i kolor Doppler ultrazvučni (CDU) pregled krvnih sudova nedominantne ruke sa merenjem dijametra cefalične vene (CVd), radijalne arterije (ARd), brahijalne arterija (ABd), indeksa rezistencije (RI), venskog distenzibiliteta (VD), endotelom posredovane dilatacije brahijalne arterije (FMD). Sve AVF su bile radicefalične po tipu lateroterminalne anastomoze. Maturacija AVF je bila praćena merenjem protoka krvi (Qa) kroz AVF i CVd 0, 14 I 28 dana...A prerequisite for successful hemodialysis (HD) is the existence of adequate access to the systemic circulation, which allows sufficient blood flow in the extracorporeal system. A native, radiocephalic arteriovenous fistula (RCAVF) is the preferred option for hemodialysis and the desired vascular access for vascular surgeons and nephrologists. Nevertheless, a significant failure-to-mature rate is a barrier to overcome. Several studies have assessed factors associated with AVF failure. Older age, female sex, diabetes, race, preexisting cerebrovascular or peripheral vascular diseases are some of the predictive factors. However, optimal vessel size for successful AVF creation is still a key question. In addition, data from the literature also indicate that some functional blood vessel parameters (arterial response to reactive hyperemia, vein dilatation under tourniquet and endothelial function) appear to play additional roles in maturation. Ultrasound can give us valuable information about vessel diameters, their functional characteristics and AVF readiness for use. The time from AVF creation to the moment of the first cannulation is called the period of maturation. There are different opinions regarding the timing of the first AVF cannulation. The optimal time is when the period of maturation is completed, which means that access is ready for use, and can provide adequate dialysis dose (Kt/V) with minimum risk of damage. For the above reason, the aim of this study was to investigate the influence of different (morphologic, functional and biochemical) parameters on AVF, to define the most important factors and suggest (according to obtained results) a clinical algorithm for prediction of the radiocephalic AVF maturation. The study included 122 consecutive end-stage kidney disease patients, who commenced hemodialysis between October 2008 and April 2010. All patients were hospitalized at the Clinic of Nephrology, Clinical Center of Serbia to create a primary native AVF, in order to be prepared for the chronic hemodialysis program. All patients were informed about the planned procedure and gave informed consent. The study was approved by the Clinical Center of Serbia Ethics Committee. All patients underwent pre-operative physical and Color Doppler Ultrasound (CDU) assessment of blood vessels of the non-dominant arm. Measurements of internal diameters of cephalic vein (CVd), brachial (ABd) and radial artery (ARd), venous distensibility (VD), resistance index (RI) and endothelial function by flow mediated dilatation (FMD) were determined by ultrasound examination before AVF placement..

Correlation of physiological, biochemical and morphological parameters and outcomes of native arteriovenous fistulas for hemodialysis

Preduslov za uspešnu hemodijalizu (HD) je postojanje adekvatnog vaskularog pristupa sistemskoj cirkulaciji koji omogućava dovoljan dotok krvi u vantelesnom sistemu. Nativna podlaktična radiocefalična arteriovenska fistula (RCAVF) je preferirani i željeni vaskularni pristup za hemodijalizu od strane vaskularnih hirurga i nefrologa. Međutim, visoki procenat neuspeha maturacije je barijera koju treba prevazići. Mnoge studije su ispitivale faktore povezane sa neuspehom maturacije AVF. Starost, ženski pol, dijabetes, rasa, prisustvo cerebrovaskularne ili periferne vaskularne bolesti su samo neki od prediktivnih faktora za neuspeh AVF. Međutim, optimalni dijameter krvnih sudova za kreiranje AVF ostaje i dalje ključno pitanje. Pored dijametra, neki funkcioni-fiziološki parametri izgleda da imaju dodatnu ulogu u maturaciji AVF. Ultrazvuk kao neinvazivna metoda nam može dati značajnu informaciju o morfološkim i funkcionim parametrima krvih sudova kao i o spremnosti za korišćenje AVF. Vreme od momenta kreiranja AVF do prve punkcije se zove period maturacije. Postoje razlike u mišljenju vezano za vreme prve kanulacije. Optimalno vreme je kada je process maturacije završen, a to znači da je pristup spreman za korišćenje, da može da obezbedi adekvatnu dozu dijalize (Kt/V) sa minimalnim rizikom od oštećenja. Zbog svega navedenog, cilj ovog istraživanja je bio da se ispita korelacija različitih faktora (morfoloskih, funkcionih i biohemijskih) i ishoda nativnih AVF za hemodijalizu; da se definišu faktori od najvećeg uticaja kao i da se na osnovu dobijenih rezultata predloži klinički algoritam predikcije ishoda nativnih podlaktičnih AVF. Ispitivanje je obuhvatilo 122 uzastopna bolesnika u terminalnoj fazi hronične bubrežne slabosti koji su započeli HD u periodu od Oktobra 2008 do Aprila 2010. godine. Svi bolesnici su bili hospitalizovani u Klinici za nefrologiju, Kliničkog centra Srbije radi kreiranja primarne AVF i započinjanja hroničnog programa hemodijalize. Svi bolesnici su bili informisani o procedure planiranih ispitivanja za koja su dali svoju saglasnost. Studija je odobrena od strane Etičkog komiteta Kliničkog centra Srbije. Svim bolesnicima je preoperativno obavljen fizikalni i kolor Doppler ultrazvučni (CDU) pregled krvnih sudova nedominantne ruke sa merenjem dijametra cefalične vene (CVd), radijalne arterije (ARd), brahijalne arterija (ABd), indeksa rezistencije (RI), venskog distenzibiliteta (VD), endotelom posredovane dilatacije brahijalne arterije (FMD). Sve AVF su bile radicefalične po tipu lateroterminalne anastomoze. Maturacija AVF je bila praćena merenjem protoka krvi (Qa) kroz AVF i CVd 0, 14 I 28 dana...A prerequisite for successful hemodialysis (HD) is the existence of adequate access to the systemic circulation, which allows sufficient blood flow in the extracorporeal system. A native, radiocephalic arteriovenous fistula (RCAVF) is the preferred option for hemodialysis and the desired vascular access for vascular surgeons and nephrologists. Nevertheless, a significant failure-to-mature rate is a barrier to overcome. Several studies have assessed factors associated with AVF failure. Older age, female sex, diabetes, race, preexisting cerebrovascular or peripheral vascular diseases are some of the predictive factors. However, optimal vessel size for successful AVF creation is still a key question. In addition, data from the literature also indicate that some functional blood vessel parameters (arterial response to reactive hyperemia, vein dilatation under tourniquet and endothelial function) appear to play additional roles in maturation. Ultrasound can give us valuable information about vessel diameters, their functional characteristics and AVF readiness for use. The time from AVF creation to the moment of the first cannulation is called the period of maturation. There are different opinions regarding the timing of the first AVF cannulation. The optimal time is when the period of maturation is completed, which means that access is ready for use, and can provide adequate dialysis dose (Kt/V) with minimum risk of damage. For the above reason, the aim of this study was to investigate the influence of different (morphologic, functional and biochemical) parameters on AVF, to define the most important factors and suggest (according to obtained results) a clinical algorithm for prediction of the radiocephalic AVF maturation. The study included 122 consecutive end-stage kidney disease patients, who commenced hemodialysis between October 2008 and April 2010. All patients were hospitalized at the Clinic of Nephrology, Clinical Center of Serbia to create a primary native AVF, in order to be prepared for the chronic hemodialysis program. All patients were informed about the planned procedure and gave informed consent. The study was approved by the Clinical Center of Serbia Ethics Committee. All patients underwent pre-operative physical and Color Doppler Ultrasound (CDU) assessment of blood vessels of the non-dominant arm. Measurements of internal diameters of cephalic vein (CVd), brachial (ABd) and radial artery (ARd), venous distensibility (VD), resistance index (RI) and endothelial function by flow mediated dilatation (FMD) were determined by ultrasound examination before AVF placement..

Optimal timing for vascular access creation

Many guidelines recommend that end-stage renal disease (ESRD) patients should have a permanent vascular access, preferably an autologous arteriovenous fistula (AVF), at the start of renal replacement therapy. Nevertheless, a large proportion of patients still start hemodialysis with a central venous catheter (CVC). On the other hand, there are increasing numbers of patients in whom an AVF has been created, but who never actually end up on dialysis, as well as a substantial number of patients in whom creation of a vascular access has been attempted unsuccessfully. To improve this situation, timely exploration to assess suitability for and creation of preemptive AVF should be promoted. Decision to construct an AVF should depend on the likelihood and rate of progression to ESRD. For this goal, some reliable prediction models are available. Also, the likelihood that such an attempt will result in a successful outcome should be taken into account, but suitable validated models to accurately make such estimates are lacking. Next to patient-specific factors, some local conditions such as easy access to a vascular surgeon should also be incorporated in the decision-making process between the nephrology team and the patient