Phd in ANGIO-CARDIO-THORACIC PATHOPHYSIOLOGY AND IMAGING

Thesis title: Scelte tecniche e strategie per la creazione di accessi vascolari nel paziente diabetico: correlazione tra la presenza di macro-calcificazioni arteriose e la funzionalità dell’accesso in relazione al sito di creazione.

Objectives Conflicting data exist regarding the patency and the maturation rate of native vascular access (VA) for dialysis in patients presenting with type 2 diabetes mellitus (T2DM). Despite NKDQI guidelines recommending the creation of distal native VA to lower the overall rate of complications, several authors still select to perform prosthetic arteriovenous fistulas (PAV) or proximal VA to achieve a more likely and rapid maturation in those patients, considering their decreased life expectancy and the high prevalence of macro-calcification in medium-calibre arteries that may negatively influence the function of the VA. Against this background, we aimed to provide a more extensive description of the impact of T2DM and arterial macro-calcifications on the success and complications of native VA and to help identify which site selected for the VA creation provides the best outcomes in this subpopulation of patients. Design Prospective observational single-centre study. Materials and methods This study is an observational, prospective cohort study that included all consecutive patients who underwent the first surgical creation of a native VA in a single Institution over the last two years. The patients were divided into two groups (diabetic: Group A or not: Group B) and the results were analyzed according to the presence of macro-calcification and the site (proximal or distal) selected for the VA creation. The primary outcomes were maturation and primary patency rate. Secondary outcomes were the rate of local (skin necrosis, steal syndrome, high-flow, infection, thrombosis, stenosis, delayed maturation) and systemic complications (pulmonary hypertension, heart failure), reintervention rate and mortality. Results During the study period, n=415 patients were referred for VA creation or revision and a total of n=197(n=128, 65% male, mean age 66.43±15.23 years) were enrolled in the study according to the inclusion criteria. Group A included n=85 (43.1%) patients while Group B consisted of n=112 (56.9%) patients. The two groups were statistically different only in terms of prior cerebral stroke as comorbidity (Group A n=1, 0.9% vs Gruppo B n=7, 8.2%, p=0.039). Anatomically diabetic patients presented with a higher rate of arterial macro-calcifications (Group A n=39, 34.8% vs Group B n=39, 45.9%, p=0.022 respectively) however, there was no significant difference in terms of type of VA access created (distal VA: n=71, 66.1% in Group A vs n=51,60% in Group B, p=1; and proximal VA n=38, 33% in Group A vs n=33, 38.8% in Group B, p=0.432). Overall maturation (n=97, 86.6 % in Group A vs n=71, 83.5% in Group B) was not statistically different in the two groups. At a mean follow-up of 295.71 days (range 30-1020 days), a similar rate of re-intervention (n=17, 15.2% in Group A vs n=19,22.4% in Group B, p=0.197) and complications (n=24, 21.4% in Group A vs n=27, 23.8% in Group B, p=0.101) was reported in both groups. Accordingly, the primary patency was not statistically different (p=0.364) in distal (p=0.788) nor for proximal VA (p=0.384) and was not influenced by the presence of arterial macro-calcification (proximal VA p=0.384 and distal VA p=0.788 respectively). No death was reported during the study period. Conclusion Despite Diabetes Mellitus is associated with an overall but non significative lower rate of maturation and increased rate for reintervention, no differences were found between access created proximally or distally when comparing diabetic patients with their non-diabetic counterparts. Arterial macrocalcifications seem to not have a direct impact on the fistula function neither in terms of maturation nor of primary patency. More robust data and longer-term results from randomized studies are needed to determine which fistula is the gold standard in this subgroup of patients.