Association between glomerular filtration rate and 1,25-dihydroxyvitamin D in cardiac surgery

The effects of cardiovascular and orthopaedic surgery on vitamin concentrations: a narrative review of the literature and mechanisms of action

Given the rise in worldwide chronic diseases, supplemented by an aging population, the volume of global major surgeries, encompassing cardiac and orthopedic procedures is anticipated to surge significantly. Surgical trauma can be accompanied by numerous postoperative complications and metabolic changes. The present review summarized the results from studies assessing the effects of orthopedic and cardiovascular surgery on vitamin concentrations, in addition to exploring the possible mechanisms associated with changes in concentrations. Studies have revealed a potentially severe depletion in plasma/serum concentrations of numerous vitamins following these surgeries acutely. Vitamins C, D and B1 appear particularly vulnerable to significant depletions, with vitamin C and D depletions consistently transpiring into inadequate and deficient concentrations, respectively. The possible multifactorial mechanisms impacting postoperative vitamin concentrations include changes in hemodilution and vitamin utilization, redistribution, circulatory transport and absorption. For a majority of vitamins, there has been a lack of investigation into the effects of both, cardiac and orthopedic surgery. Additionally, studies were predominantly restricted to short-term postoperative investigations, primarily performed within the first postoperative week of surgery. Overall, results indicated that further examination is necessary to determine the severity and clinical significance of the possible depletions in vitamin concentrations that ensue cardiovascular and orthopedic surgery.

Circulating 25-Hydroxyvitamin D and 1,25-Dihydroxyvitamin D Concentrations and Postoperative Infections in Cardiac Surgical Patients: The CALCITOP-Study

BACKGROUND

Vitamin D has immunomodulatory properties and seems to reduce the risk of infections. Whether low vitamin D concentrations are independent risk factors for nosocomial postoperative infections in surgical patients remains to be studied in detail.

METHODS

In 3,340 consecutive cardiac surgical patients, we investigated the association of circulating 25-hydroxyvitamin D (25OHD; indicator of nutritional vitamin D status) and 1,25-dihydroxyvitamin D (1,25[OH]2D; active vitamin D hormone) with nosocomicial infections. The primary endpoint was a composite of thoracic wound infection, sepsis, and broncho-pulmonary infection. Vitamin D status was measured on the last preoperative day. Infections were assessed until discharge. Logistic regression analysis was used to examine the association between vitamin D metabolite concentrations and the composite endpoint.

RESULTS

The primary endpoint was reached by 5.6% (n = 186). In patients who reached and did not reach the endpoint, in-hospital mortality was 13.4% and 1.5%, respectively (P<0.001). Median (IQR) 25OHD and 1,25(OH)2D concentrations were 43. 2 (29.7-61.9) nmol/l and 58.0 (38.5-77.5) pmol/l, respectively. Compared with the highest 1,25(OH)2D quintile (>81.0 pmol/l), the multivariable-adjusted odds ratio of infection was 2.57 (95%CI:1.47-4.49) for the lowest 1,25(OH)2D quintile (<31.5 pmol/l) and 1.85 (95%CI:1.05-3.25) for the second lowest quintile (31.5-49.0 pmol/l). There was no significant association between 25OHD concentrations and the primary endpoint.

CONCLUSIONS

Our data indicate an independent association of low 1,25(OH)2D levels with the risk of postoperative infections in cardiac surgical patients. Future studies should pay more attention on the clinical relevance of circulating 1,25(OH)2D and its regulation.

Vitamin D status and surgical outcomes: a systematic review

The importance of vitamin D for musculoskeletal health has long been recognized, and awareness of significant extra-skeletal effects in health and disease is rapidly emerging. Although it has been possible for many decades to quantify serum markers of vitamin D deficiency, and to correct deficiency at low cost and with high safety, the influence of vitamin D status on post-surgical outcomes has only recently been identified as a research topic of interest. To the present, these data have not been the subject matter of formal review. Accordingly, we conducted a systematic review to assess the association between perioperative vitamin D status and outcomes after surgery. The databases of PubMed, Ovid MEDLINE, EMBASE, AMED, CINAHL (EBSCOHost), The Cochrane Databases of Systematic Review, and PROSPERO were searched through December, 2014 for studies relating to vitamin D and surgery. The initial search yielded 90 manuscripts. After applying exclusion criteria, 31 studies were eligible for inclusion. Fifteen studies employed prospective observational designs, 3 used prospective randomized protocols, and 13 report retrospective database interrogations. The main finding of the present review is that 26 of 31 studies (84%) report at least one statistically significant worse outcome in patients with low vitamin D status. Five of 31 studies (16%) found no association. In conclusion, this review supports the hypothesis that hypovitaminosis D is associated with adverse outcomes after diverse surgical procedures. Future studies should focus on additional surgeries and outcomes, and on the role of vitamin D supplementation in the improvement of patient safety in participants with low vitamin D status at the time of surgery.

Vitamin D deficiency in surgical congenital heart disease: prevalence and relevance

Vitamin D is a pleiotropic hormone important for the proper functioning of multiple organ systems. An emerging body of adult and pediatric critical care literature strongly suggests that vitamin D deficiency contributes to secondary organ pathophysiology, prolongs ICU stay, and worsens outcome in critically ill populations. Recent clinical studies suggest that a significant number of children with congenital heart disease (CHD) have post-operative vitamin D deficiency which appears to be associated with greater cardiovascular dysfunction. Altogether the cumulative body of literature suggests that peri-operative optimization of vitamin D status has the potential to speed recovery and/or improve outcome. This review describes the epidemiological and basic science research linking vitamin D deficiency to post-operative organ dysfunction. Furthermore, the available supplementation approaches are reviewed in the context of prevention of post-operative vitamin D deficiency and avoidance of toxicity in the majority of CHD patients. Finally, knowledge gaps regarding vitamin D supplementation are identified and the next stages for research are outlined.