Cerebrovascular accidents in patients supported with veno-arterial extra-corporeal membrane oxygenation- is duration of support important?

Purpose of study

Veno-Arterial Extra-corporeal Membrane Oxygenation (VA-ECMO) is indicated for refractory cardiac and/or respiratory failure. Adverse events remain considerable despite best practices. We specifically aimed to understand risk factors associated with cerebrovascular accidents (CVA) in patients who underwent VA-ECMO support.

Methods

We retrospectively assessed all VA-ECMO patients from 2007 to 2019 at our institution. We identified those who experienced a CVA while supported by VA-ECMO. Patients with the primary event (CVA) were matched to controls (no CVA) based on age and sex. Comparisons were made between groups using McNemar's, Mantel-Haenszel, and Wilcoxon Signed-Rank tests where appropriate.

Results

Of the 278 VA-ECMO patients in the registry, 32 patients who experienced a CVA were identified; 24 (8.6%) ischemic and 8 (2.9%) hemorrhagic. Median age was 59.5 years (inter-quartile range: 49–65 years) and 75% of patients were males. Hypertension, diabetes, CAD and CHF were common co-morbidities (Table 1). Cardiogenic shock was the most common indication for VA-ECMO support in both cohorts, 75% in cases and 71.9% in controls. Cannulation strategies were identified as central or peripheral. There was a significant association of duration of VA-ECMO support with incidence of CVA, with a p-value of 0.03. Regression analysis showed a trend of increased risk of CVA by 4% for each additional day on VA-ECMO, however, this was not statistically significant (Odds ratio: 1.04; confidence interval 1.00–1.08). Most common outcome was death followed by decannulation to recovery and bridge to LVAD.

Conclusion

Ischemic and hemorrhagic CVAs are not uncommon during VA-ECMO support. Our case control study shows an association of duration of VA-ECMO support with incidence of CVA. This underscores the importance of timely assessment and weaning or bridging of VA-ECMO patients to their next management step.

Funding Acknowledgement

Type of funding sources: None.

Antigenicity of human melanoma cells transfected to express the B7-1 co-stimulatory molecule (CD80) varies with the level of B7-1 expression

The aim of this study was to compare the antigenicity of human melanoma cells molecularly modified by particle-mediated gene transfer to have transient or stable expression of the B7-1 co-stimulatory molecule (CD80). The unmodified melanoma cells (mel5, m21) had no constitutive expression of B7-1, but 22%-28% of cells had transient B7-1 expression 24 h following transfection with cDNA for B7-1 (mel5-B7, m21-B7). In addition, 85%-90% of cells had stable B7-1 expression following transfection with cDNA for B7-1 and in vitro culture under selection conditions (mel5-B7neo, m21-B7neo). Allogeneic HLA-unmatched normal donor peripheral blood mononuclear cells (PBMC) secreted greater amounts of granulocyte/macrophage-colony-stimulating factor (GM-CSF) when incubated for 3 days with m21-B7neo than did PBMC incubated with m21-B7, which, in turn, secreted greater amount of GM-CSF than PBMC incubated with m21. Similarly, cell-mediated cytotoxicity against unmodified melanoma cells by PBMC co-cultured for 5 days with the modified or unmodified melanoma cells was proportional to the level of B7-1 expression on the stimulating cells. This cytolytic activity had both an HLA-class-I-restricted and an HLA-class-I-unrestricted component. Following 5 days of co-culture, PBMC expression of CD28, the ligand for B7-1, was down-regulated in proportion to the level of B7-1 expression on the stimulating melanoma cells. Thus, particle-mediated gene delivery of cDNA for B7-1 into human melanoma cells increased expression of functional B7-1 and enhanced the antigenicity of the gene-modified cells in proportion to their level of B7-1 expression.