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..

Kliničke praktične smjernice za perioperacijsku i poslijeoperacijsku skrb o arterijsko-venskim fistulama i umetcima za hemodijalizu u odraslih

Krvožilni pristup omogućuje hemodijalizu koja spašava život. Stoga je nužna dobra funkcija krvožilnog pristupa koja omogućuje prikladan krvni protok radi uklanjanja tvari koje se u uremiji zadržavaju u krvi bolesnika, uz istodobno sniženje rizika od sustavne infekcije na najmanju moguću mjeru. Godine 2007. Europske smjernice najbolje prakse (engl. European Best Practice Guidelines – EBPG), prethodnice trenutačne Europske najbolje bubrežne prakse (engl. European Renal Best Practice – ERBP), donijele su nacrt skupine preporuka – vodiča pri donošenju odluka o upućivanju na pregled radi krvožilnog pristupa, o procjeni i nadzoru izbora pristupa te o postupcima kod komplikacija. (1) Otad su se znatno razvili ne samo dokazi na kojima se temelje ove preporuke nego i procesi nastajanja smjernica. (2) Kao odgovor na to, ERBP je ažurirao prethodno djelo u suradnji s raznim stručnjacima iz tog područja uključujući i predstavnike Društva za krvožilni pristup (engl. Vascular Access Society – VAS), kirurge za krvožilni pristup, radiologe, medicinske sestre za dijalizu, znanstvenike, bolesnike i one koji se za njih brinu. Nastojanje da se pridržavaju sve strože metodike izrade smjernica nalagalo je određena odricanja u pogledu područja obuhvata ovih smjernica. Posljedično, one ne „pokrivaju” baš sve iste teme kao njihova prethodna verzija. Neka su područja zajednička, a neka su arhivirana da bi ustupila mjesto novim pitanjima kojima su prednost dali i pružatelji zdravstvene skrbi i oni za koje se skrbi. Odvojeno su objavljene pojedinosti postupka izbora djelokruga problematike koju su smjernice obuhvatile. (3) Nastajanje ovih smjernica slijedilo je strog proces pregleda i procjene dokaza koji se temeljio na sustavnim pregledima rezultata kliničkih istraživanja te opservacijskih podataka gdje je to bilo potrebno. Strukturirani pristup slijedio je model sustava GRADE (hrv. stupanj), koji svakoj preporuci pripisuje stupanj s obzirom na sigurnost sveukupnih dokaza te snagu. (4) Gdje je to bilo primjereno skupina za izradu smjernica unijela je nestupnjevan savjet za kliničku praksu, a koji nije proistekao iz pregleda sustavnih dokaza. Kliničke praktične smjernice iz 2019. godine specifično pokrivaju peritransplantacijske i poslijetransplantacijske aspekte arterijsko-venskih (AV) fistula i umetaka (graftova). Drugi dio, koji je bio u nastajanju kada su ove smjernice išle u tisak, pokrit će aspekte izbora krvožilnog pristupa, prijeoperacijske procjene krvnih žila i središnje venske katetere. Unatoč nedostatku dokaza velike sigurnosti za većinu područja krvožilnih pristupa, ERBP se posvetio izradi smjernica velike kakvoće, dajući smjernicu gdje god je moguće, a popis preporuka za istraživanje ondje gdje se nije moglo uputiti smjernicom. Nadamo se da će ove smjernice i one planirane pomoći stručnoj zajednici pri donošenju odluka o postupcima, postupnicima i skrbi vezanima s krvožilnim pristupima, pomoći bolesnicima i onima koji se za njih brinu da steknu uvid u problematiku te olakšati zajedničko donošenje odluka u tom području

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

High rate of native arteriovenous fistulas: How to reach this goal?

The types of vascular accesses for hemodialysis (HD) include the native arteriovenous fistula (AVF), arteriovenous graft (AVG) and central venous catheter (CVC). Adequately matured native AVF is the best choice for HD patients and a high percentage of its presence is the goal of every nephrologist and vascular surgeon. This paper analyses the number and type of vascular accesses for HD performed over a 10-year period at the Clinical Center of Serbia, and presents the factors of importance for the creation of such a high number of successful native AVF (over 80%). Such a result is, inter alia, the consequence of the appointment of the Vascular Access Coordinator, whose task was to improve the quality of care of blood vessels in the predialysis period as well as of functional vascular accesses, and to promote the cooperation among different specialists within the field. Vascular access is the “lifeline” for HD patients. Thus, its successful planning, creation and monitoring of vascular access is a continuous process that requires the collaboration and cooperation of the patient, nephrologist, vascular surgeon, radiologist and medical personnel

Clinical practice guideline on peri- and postoperative care of arteriovenous fistulas and grafts for haemodialysis in adults

The ericoid shrub Vaccinium myrtillus is one of several deciduous boreal plants that respond to larval defoliation by compensatory production of a new set of leaves within the same growing season soon after defoliation. This new set is termed as ‘secondary leaves’. The physiological performance and longevity of secondary leaves is poorly understood. Following a multi-year larval outbreak in boreal Norway, we therefore monitored the fate of the secondary leaves from 2014 to 2016. We observed that secondary leaves were still green upon onset of snow season and that the same leaves were still attached and green when snow melted in spring. During the early growing season of 2015, the overwintering leaves were consumed by moth larvae, but the secondary leaves produced in mid-July 2015 overwintered and were not consumed by larvae the next growing season. Our monitoring shows that most of these leaves remained attached until late August, while the contents of chlorophyll and nitrogen remained high until July. The flavonoid (anthocyanin) content of overwintering leaves increased shortly after snowmelt, and this coincided with a short-lasting colour change from green to violet-bronze. This was probably a protective response to the abrupt increase in solar radiation. Overall, secondary, overwintering leaves were free of snow and physiologically active for ca 6.5 months, which is 2–3 months more than the longevity of primary leaves in the study area. We conclude that wintergreen leaves probably rendered an important carbon sequestration contribution in the critical first phase of the growing season until new side branches with new leaves were developed. Hence, the novel results reported here on the facultative wintergreen growth habit of V. myrtillus appears to be a successful strategy

Clinical practice guideline on peri- and postoperative care of arteriovenous fistulas and grafts for haemodialysis in adults [Erratum]

In the original version, reference 35 had the incorrect journal title. This has now been amended. An additional affiliation has also been added for author Tamara Jemcov

Clinical practice guideline on peri- and postoperative care of arteriovenous fistulas and grafts for haemodialysis in adults. [Erratum]

Text has been added to the article in the ‘Study Selection’ paragraph, explaining the inclusion criteria for selecting the abstracts