Delirium is a sudden onset of acute confusion in which those affected are disoriented, have impaired attention and altered perception – often accompanied by hallucinations or sleep disturbances. In cardiology, this is one of the most common but also one of the most underestimated complications. Older patients who have undergone cardiac surgery or interventional procedures are particularly affected. A new international state-of-the-art review involving leading cardiologists, cardiac surgeons, intensive care physicians and psychiatrists has come to an alarming conclusion: delirium is much more than temporary confusion. It is associated with longer intensive care and hospital stays, increased mortality, higher rates of care dependency and a significantly increased risk of permanent cognitive impairment. Furthermore, delirium is an independent predictor of long-term mental decline – even in individuals who previously showed no cognitive impairment.
High incidence of delirium – serious consequences
Depending on the procedure and survey method, a significant number of patients develop delirium. Complex cardiac surgery in particular, but also interventional procedures such as TAVR or PCI, are by no means risk-free, especially in the case of very elderly patients and those with pre-existing conditions. That is why Prof. Dr. Dr. Enzo Lüsebrink, a cardiologist from Bonn and co-author of the study, and Prof. Dr. Georg Nickenig, Director of the Clinic for Cardiology at the UKB, are clear: "Delirium is not a marginal problem, but one of the central complications of modern cardiac medicine."
Often overlooked, rarely systematically recorded
Despite its clinical relevance, delirium often goes unrecognised in cardiovascular practice. The so-called hypoactive form in particular – characterised by apathy, reduced activity and listlessness – often remains undiagnosed and is mistakenly interpreted as age-related or exhaustion. "Validated and standardised screening instruments such as the Confusion Assessment Method, or CAM for short, with corresponding extensions for intensive care units, which can be used quickly and reliably, are still far too rarely used routinely in everyday clinical practice," says co-first author Endrit Cekaj, assistant physician at the Clinic for Cardiology at the UKB.
Prevention is crucial
A key finding of the review: the most effective strategy against delirium is prevention. Multimodal, non-pharmacological measures – including early mobilisation, reorientation, sleep hygiene, cognitive stimulation, adequate pain management and the involvement of relatives – can reduce the incidence of delirium by up to 40 per cent. However, the study takes a critical view of the routine prophylactic use of medication.
"We also clearly show that delirium does not have to be accepted as inevitable, even if it occurs despite consistent prevention," says co-first author Dr David H.V. Vogel, head of the Experimental Psychopathology research group at the Department of Psychiatry and Psychotherapy at the UKB. Based on current evidence and an interdisciplinary expert consensus, the authors formulate structured treatment approaches that are based on severity, clinical setting and delirium subtype.
Treatment of delirium: evidence-based and practical
The focus continues to be on non-pharmacological measures. These form the therapeutic basis for all degrees of severity. In addition, pharmacological options are presented in a differentiated manner where clinically necessary. In intensive care medicine in particular, the sedative dexmedetomidine has been shown to be beneficial in cases of moderate to severe delirium. Antipsychotic substances can be used depending on the situation and symptoms, whereby the benefits and potential cardiac side effects must be carefully weighed up.
"A structured, step-by-step approach is crucial," explains Prof. Lüsebrink. "Our work shows that evidence-based and clinically practicable treatment strategies also exist in the cardiovascular setting – provided that delirium is detected early and treated in an interdisciplinary manner." Co-last author Prof. Dr. Alexandra Philipsen, Director of the Clinic for Psychiatry and Psychotherapy at UKB, explains why a holistic view is so important: "We can successfully treat our patients' hearts medically. But if we do not systematically recognise and prevent delirium, we risk long-term damage to the brains of those affected. Delirium prevention must therefore become an integral part of cardiovascular care."
Despite growing knowledge, evidence remains limited, especially for cardiovascular patient groups. The authors therefore call for targeted, prospective studies to develop specific guidelines for prevention and treatment.
Original publication: Cekaj E., et al., Delirium in cardiovascular medicine, European Heart Journal, Feb 2026
Source: Press release Bonn University Hospital
