Effect of Cardiopulmonary Bypass on SARS-CoV-2 Vaccination Antibody Levels

Remimazolam inhibits postoperative cognitive impairment after cardiopulmonary bypass by alleviating neuroinflammation and promoting microglia M2 polarization

Postoperative cognitive impairment (POCD) is a complication of cardiopulmonary bypass (CPB). Remimazolam is an ultra-short acting benzodiazepine that can be used for anesthesia or sedation during surgery. This study investigated the role of remimazolam in inflammasome activation and microglia polarization using CPB rat model and lipopolysaccharide (LPS)-induced microglia model. The cognitive function of rats was evaluated by Morris water maze. TUNEL assay was performed to detect apoptosis. Inflammatory cytokines concentration were analyzed by enzyme-linked immunosorbent assay. Reverse transcription-polymerase chain reaction was used to assess the expression of inflammasome and M1/M2-related microglia markers. Flow cytometry was performed to evaluate the expression of CD16/32 and CD206 in microglia. The results showed that remimazolam improved the memory and learning abilities in CPB rats. CPB rats and LPS-treated microglia showed increased apoptosis, pro-inflammatory cytokines level, and inflammasome expression as well as decreased microglia activation, while the results were reversed after remimazolam treatment. Besides, remimazolam treatment promoted the expression of M2-related markers in LPS-treated microglia. Nigericin treatment reversed the increased M2-related mRNA levels and the decreased apoptosis and inflammatory responses induced by remimazolam treatment. In conclusion, remimazolam attenuated POCD after CPB through regulating neuroinflammation and microglia M2 polarization, suggesting a new insight into the clinical treatment of POCD after CPB.

Immunisation deferral practices surrounding congenital heart surgery

BACKGROUND

Perioperative immunisation administration surrounding congenital heart surgery is controversial. Delayed immunisation administration results in children being at risk of vaccine-preventable illnesses and is associated with failure to complete immunisation schedules. Among children with CHD, many of whom are medically fragile, vaccine-preventable illnesses can be devastating. Limited research shows perioperative immunisation may be safe and effective.

METHODS

We surveyed Pediatric Acute Care Cardiology Collaborative member centres and explored perioperative immunisation practices. We analysed responses using descriptive statistics.

RESULTS

Complete responses were submitted by 35/46 (76%) centres. Immunisations were deferred for any period prior to surgery by 23 (66%) centres and after surgery by 31 (89%) centres. Among those who deferred post-operative immunisation, 20 (65%) required deferral only for patients whose operations required cardiopulmonary bypass. Duration of deferral in the pre- and post-operative periods was variable. Many centres included exceptions to their policy for specific vaccine-preventable illnesses. Almost all (34, 97%) centres administer routine childhood immunisation to patients who remain admitted for prolonged periods.

CONCLUSIONS

Most centres defer routine childhood immunisation for some period before and after congenital heart surgery. Centre specific practices vary. Immunisation deferral confers risk to patients and may not be warranted in this population. Further research would be necessary to understand the immunologic impact of these practices.

Optimal timing of SARS-CoV-2 vaccination prior to cardiovascular surgery under cardiopulmonary bypass

BACKGROUND

mRNA vaccines against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) became common. We investigated the optimal timing for inoculation against SARS-COV-2 in the candidates for cardiac surgery under cardiopulmonary bypass (CPB).

METHODS

In 100 patients with preoperative vaccination, who underwent CPB surgery between July 2021 and February 2022, the IgG against the receptor binding domain (RBD-IgG), with a threshold of >100 binding antibody unit (BAU)/mL for adequate immunity, was measured.

RESULTS

The vaccines, including 87 BNT162b2 (Pfizer/BioNTech) and 13 mRNA-1273 (Moderna), were inoculated at 98.8 ± 59.4 days before surgery. The median RBD-IgG titers before surgery, 1 day after surgery, and 1 month after surgery were 166.8, 100.0, and 84.0 BAU/mL, respectively. The standby interval (SBI) from the vaccination to the surgery showed a significantly negative correlations with the RBD-IgG titer before the surgery (p < 0.001). A cut-off SBI for RBD-IgG >100 BAU/mL before surgery was <81 days with a sensitivity of 76%, specificity of 62%, and area under ROC value of 0.73 (p = 0.03). The patients with SBI <81 days (n = 48) had significantly higher RBD-IgG (>100 BAU/mL) than those with SBI ⩾81 days (n = 52) at all perioperative periods.

CONCLUSIONS

Although 40% of the RBD-IgG titers reduce 1 day after CPB surgery, the patients who received the SARS-COV-2 vaccination within an 81-day window prior to the surgery maintained a desirable RBD-IgG level, even up to 1 month after surgery. It may be important to schedule the surgery no later than 81 days after the vaccination.