Delirium is a common and severe postoperative complication among older patients undergoing vascular surgery[1, 2]. This severe neuropsychiatric disorder has a complex, multifactorial aetiology that is still mostly unknown[3, 4]. Added to the fact that a delirium could have a variety of serious consequences such as a prolonged hospital stay, institutionalization after discharge, functional and cognitive decline, significant healthcare costs and eventually death, it is thought to be a preventable condition in 30-40% of the cases[5-9]. There are few publications about the prevention of delirium in vascular surgery specifically, although it is a highly important issue. The purpose of this study is to identify strategies for the prevention of delirium in patients undergoing elective treatment for peripheral arterial disease (PAD) or an aneurysm of the abdominal aorta (AAA).

This systematic review followed the PRISMA[10] guidelines and was pre-registered in PROSPERO. A search was conducted using the keywords 'vascular surgery', 'prevention', and 'delirium', and was last conducted on October 21st, 2021 in the electronic databases Pubmed, MEDLINE, Embase, Web of Science, the Cochrane library, and Emcare. Studies describing strategies for preventing delirium in patients undergoing elective surgery for PAD or for an AAA were included in this review. Risk of bias was assessed using the Cochrane Risk of Bias tool[11] for randomized controlled trials and the ROBINS-1 tool[12] for observational studies.

The database search identified 1588 studies. Four studies including a total of 565 patients were eventually included in this systematic review. A significant reduction in delirium incidence was reported in two of the four articles. Among them was a RCT of Partridge et al. investigating the effect of performing a comprehensive geriatric assessment (CGA) with subsequent delirium preventive interventions in patients who underwent AAA repair or lower limb bypass surgery (delirium incidence of 24% in the control group versus 11% in the intervention group, p = 0.018)[13]. The other study that showed a significant decrease in delirium incidence was the before-and-after study of Janssen et al. that examined the effect of outpatient clinic multimodal prehabilitation for patients with an AAA (11.7% in the control group versus 8.2% in the intervention group, after adjustment for prognostic confounders: p = 0.043, OR = 0.56)[14]. They assessed patients on basic health, fitness and factors of frailty and provided nutritional advice, home-based exercises, a CGA in case of frailty and an iron infusion in case of anaemia. The before-and-after study of Mudge et al. that investigated the effect of a multidisciplinary quality improvement in patients at a vascular surgical ward, described a non-significant decrease in delirium incidence (21.4% in the control group versus 14.6% in the intervention group, p = 0.17)[15]. Their program consisted of the 'eat, walk, engage project', with focus on early mobility, nutrition and hydration and cognitive activities. The final study was a RCT of Papaioannou et al. that examined the effect of the type of anaesthesia on cognitive status and delirium incidence[16]. Patients of other surgical specialisms were also part of this study population. Delirium was reported in 3 of the 11 vascular surgery patients, however it was not reported whether these patients received general or regional anaesthesia.

This systematic review shows that little is known about effective prevention strategies for delirium in vascular surgery, despite the high incidence of delirium in the growing elderly vascular population[19-21]. An approach to address multiple risk factors simultaneously seems to be promising in delirium prevention, whether through multimodal prehabilitation or comprehensive geriatric assessments. Several strategies including prehabilitation programs have been proven to be successful in other types of surgery and further research is required to evaluate effective preventive strategies and prehabilitation programs in vascular surgical patients.

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