JMIR Publications

ABSTRACT

Background:

Cardiac surgery patients are at particular risk of postoperative acute respiratory distress syndrome (ARDS), with an estimated incidence of 5–10%. Cardiopulmonary bypass (CPB), ischaemia-reperfusion injury, and blood product transfusions are well-recognized contributing factors. Asymptomatic carriage of respiratory viruses has been hypothesised to prime the lungs and potentiate ARDS development when combined with the pulmonary insults of cardiac surgery. However, no study has directly assessed the relationship between preoperative asymptomatic viral carriage and postoperative ARDS.

Objective:

The VIRUS-ATTAC study aims to determine whether asymptomatic carriage of influenza or other respiratory viruses is independently associated with postoperative ARDS following elective cardiac surgery under CPB.

Methods:

VIRUS-ATTAC is a prospective, multicentre, low-interventional clinical study conducted across five French university hospitals, sponsored by Rennes University Hospital. Adult patients scheduled for elective cardiac surgery under CPB are eligible. A nasopharyngeal flocked swab is collected at anaesthesia induction and tested using a multiplex RT-PCR assay (Allplex™ Respiratory Panel, Seegene, Düsseldorf, Germany) detecting 16 respiratory viruses. Results are kept blinded to the clinical team. The primary outcome is ARDS within 7 postoperative days, defined using the Berlin criteria and adjudicated by an independent blinded committee. Secondary outcomes include reintubation, postoperative pulmonary complications, pneumonia, ventilator-free days, ICU-free days, hospital-free days, and 28-day mortality. The primary analysis uses a causal inference framework with a directed acyclic graph (DAG) for confounder selection and G-computation to estimate the average treatment effect of viral carriage on ARDS risk. A sample size of 1250 patients (including 250 asymptomatic influenza carriers) provides 80% power to detect a 5% absolute risk increase in ARDS (two-sided α = 0.05).

Results:

The VIRUS-ATTAC study (ClinicalTrials.gov NCT04562207) received ethics approval from the Comité de Protection des Personnes Sud-Est VI and recruitment was initiated in February 2021 across five French university hospitals. Data collection has been completed.

Conclusions:

VIRUS-ATTAC is the first prospective multicentre study to directly evaluate the association between preoperative asymptomatic respiratory viral carriage and postoperative ARDS in cardiac surgery patients. If confirmed, this association would support simple preventive strategies, including systematic preoperative vaccination or postponement of elective surgery in carriers, to reduce postoperative respiratory complications. Clinical Trial: The study is registered at ClinicalTrials.gov (NCT04562207)