Chronic utilization of agents acting on the renin-angiotensin system and intraoperative arterial pressure.

BACKGROUND: There has been concern that taking agents acting on the renin-angiotensin system (ARAS) in surgery day, may predispose patients to higher risk of intraoperative hypotension during surgery. Therefore, the European Society of Cardiology and the European Society of Anesthesiology recommend transient discontinuation of ARAS before non-cardiac surgery in hypertensive patients. As the existent evidence is limited, this recommendation remains debated. AIM: The objectives of the study were to evaluate the effects of ARAS chronic utilization on intraoperative arterial pressure. PATIENTS AND METHODS: This historical cohort consisted in recruitment of surgery patients over 12 months, at "Cova da Beira Hospital Center". The data were gathered from an interview to the patient and by postoperative review of the medical record. RESULTS: The study consisted of 756 patients. Of those, 589 did not take antihypertensive medication and 176 were taking chronic ARAS. In univariate analysis, only the appearance of intraoperative hypertension was significantly greater in ARAS group. In logistic regression analysis, age, diabetes mellitus and taking ARAS were the only significant risk factors to the appearance of intraoperative hypertension. In ARAS group, 123 patients stopped the ARA before surgery and 53 continued it until the surgery day. The frequency of the two outcomes did not differ between the two groups. CONCLUSIONS: In our study hypotension episodes during non-cardiac surgery could not be attributed to ARAS chronic utilization and taking ARAS on surgery morning when compared with withdrawal was not associated with hypotension episodes.

Guidelines for the management of chronic medication in the perioperative period: systematic review and formal consensus.

WHAT IS KNOWN AND OBJECTIVE: The worldwide volume of surgery is huge and the number of interventions performed is increasing as a result of advances in technological resources and refinement of medical teams' expertise, in a progressively elderly and sick population. Consequently, half of the general surgical patients take medications unrelated to surgery. Evidence-based guidelines for perioperative medication management are therefore critically needed to improve safety in surgery. The purpose of this work was to develop practice recommendations for the management of chronic medication in the perioperative period. METHODS: A systematic review and a formal consensus were performed. A search in Medline, Embase, ISI Web of Knowledge and Medscape were conducted in September 2008. Two independent investigators assessed the quality of selected studies. Evidence-based guidelines with strength classification were found for some therapeutic groups. Those guidelines were adopted and no further analysis was performed. For the other therapeutic groups, a formal consensus was used, based on a modified nominal group technique: 32 statements were formulated considering the literature retrieved. A selected panel of experts was asked by electronic mail to rate their level of agreement with each statement. Then, a meeting was convened and a second round survey was used to determine the final level of agreement. The statements which met the established criteria of consensus were developed into practice recommendations, supported by the results of the formal consensus and the evidence-based findings from systematic review. RESULTS AND DISCUSSION: A total of 23 studies were included in the systematic review; three randomized controlled trials (RCTs), 13 cohorts, two case-controls and three clinic-cases. Twenty-two practice recommendations for the management of chronic medication in the perioperative period resulted from formal consensus. WHAT IS NEW AND CONCLUSION: Epidemiological studies concerning the perioperative management of chronic medications are clinically heterogeneous and there are few RCTs available. However, the formal consensus method proved to be a helpful tool to integrate different strands of evidence for the development of practice guidelines.

Biotribocorrosion (tribo-electrochemical) characterization of anodized titanium biomaterial containing calcium and phosphorus before and after osteoblastic cell culture.

The purpose of this study was to investigate the relationship between the osteoblastic cells behavior and biotribocorrosion phenomena on bioactive titanium (Ti). Ti substrates submitted to bioactive anodic oxidation and etching treatments were cultured up to 28 days with MG63 osteoblast-like cells. Important parameters of in vitro bone-like tissue formation were assessed. Although no major differences were observed between the surfaces topography (both rough) and wettability (both hydrophobic), a significant increase in cell attachment and differentiation was detected on the anodized substrates as product of favorable surface morphology and chemical composition. Alkaline phosphatase production has increased (≈20 nmol/min/mg of protein) on the anodized materials, while phosphate concentration has reached the double of the etched material and calcium production increased (over 20 µg/mL). The mechanical and biological stability of the anodic surfaces were also put to test through biotribocorrosion sliding solicitations, putting in evidence the resistance of the anodic layer and the cells capacity of regeneration after implant degradation. The Ti osteointegration abilities were also confirmed by the development of strong cell-biomaterial bonds at the interface, on both substrates. By combining the biological and mechanical results, the anodized Ti can be considered a viable option for dentistry.