1961

NATIVE VALVE ENDOCARDITIS IN HAEMODIALYSIS PATIENTS USING BUTTON HOLE CANNULATION

Williams, JK, Bingham, C, D’Souza RJ, Oakaby, L

Exeter Kidney Unit, Royal Devon and Exeter Hospital.

INTRODUCTION: Vascular access related bacteraemia remains a major cause of morbidity and mortality in the haemodialysis (HD) population. The incidence of bacteraemia associated with arteriovenous fistulae is thought to be lower than synthetic grafts and central venous cannulae. Over recent years button hole cannulation (BHC) has become increasingly widespread. This technique involves dialysis needles being inserted into the same location, at the same angle and ideally by the same individual for each treatment, resulting in scarring and tract formation. Several factors associated with BHC may increase the risk of infection; inadequate training, poor hygiene, self-cannulation in an unsupervised environment, formation of false tracts and loss of skin integrity.

METHODS: We reviewed our total HD population, the numbers using BHC and the infection rates in this group during 2013.

RESULTS: In our HD population of 331, 87% were dialysing via an arteriovenous fistula or graft. At the beginning of 2013 55 patients were using BHC. Within a three month period in early 2013 four of these patients presented with native valve endocarditis, see Table 1. Only one patient had a possible alternative precipitant for their bacteraemia having had a recent tooth extraction, and the causative organism (strep mitalis/oralis) would support this. This same patient was the only individual to have had concerns raised regarding skin integrity and had received treatment for cellulitis over the fistula prior to the diagnosis of endocarditis.

Table 1: Patient characteristics

Age (years) / Affected Valve / Pre-existing valve lesion (type) / Organism / Time using BHC (months) / Home vs. unit HD
Case 1 / 45 / Mitral / Yes (Calcified MV but no incompetence/stenosis) / Staphylococcus aureus / 40 / Home
Case 2 / 55 / Mitral / Yes (Heavily calcified MV, mild MR) / Culture negative / 31 / Unit
Case 3 / 61 / Mitral / No / Streptococcus mitis/oralis / 22 / Unit
Case 4 / 53 / Aortic / Yes (Mild AS + AR) / Staphylococcus lugdenesis / 21 / Unit

Key: MV – mitral valve; MR – mitral regurgitation; AS – aortic stenosis; AR – aortic regurgitation

CONCLUSIONS: Our concern is that in the HD population, who are at high risk of infective endocarditis the relative protection afforded by dialysis via a fistula may be compromised by use of BHC, especially if rigorous fistula hygiene is not adhered to. These observations have led to a change in local practice; a set of suitability criteria for BHC have been developed and all nursing staff performing BHC have undergone re-education with regards the importance of appropriate skin sterilization. Patients are counselled and consent obtained. Clinicians should be aware of the risk of endocarditis in those patients using BHC.