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Enumeration of circulating endothelial cell frequency as a diagnostic marker in aortic valve surgery - a flow
Anton Sabashnikov1,2, Klaus Neef3,4, Vera Chesnokova3
1Department of Cardiothoracic Surgery, Heart Center, University Hospital Cologne, Cologne, Germany. a.sabashnikov@gmail.com.
Insights
A new automated flow cytometry method accurately measures circulating endothelial cells (CEC), revealing higher CEC levels in higher-risk trans-catheter aortic valve implantation (TAVI) patients pre- and post-procedure. Conventional aortic valve replacement (CAVR) showed higher CECs days later, indicating procedure invasiveness.
Area of Science:
- Cardiovascular Research
- Hematology
- Medical Technology
Background:
- Circulating endothelial cells (CEC) indicate endothelial damage but are difficult to quantify.
- Conventional methods for CEC enumeration present significant challenges.
- A novel automated approach was developed to determine CEC frequencies.
Purpose of the Study:
- To develop and validate a novel automated flow cytometric approach for CEC enumeration.
- To compare CEC frequencies in patients undergoing conventional aortic valve replacement (CAVR) versus trans-catheter aortic valve implantation (TAVI).
- To assess CEC frequency as a marker for pre-operative risk and surgical invasiveness.
Main Methods:
- CEC frequencies were assessed using flow cytometry with automated CD34+ pre-enrichment.
- Isotype controls were utilized for accuracy.
- Method validation involved spiking healthy donor blood with known numbers of endothelial cells.
Main Results:
- CEC frequencies were significantly higher in the TAVI group pre- and 1-hour post-surgery compared to CAVR.
- Higher pre-operative risk scores (Euroscore, STS score) correlated with higher CECs in the TAVI group.
- Five days post-surgery, CEC frequencies were significantly higher in the more invasive CAVR group than in the TAVI group.
Conclusions:
- The automated flow cytometric method offers a robust and reliable approach for CEC enumeration.
- CEC frequency serves as a valid clinical marker for assessing pre-operative risk and surgical invasiveness.
- Further research is needed to confirm the clinical utility and superiority of this method over conventional markers.
Background:
The frequency of circulating endothelial cells (CEC) in patients' peripheral blood can be assessed as a direct marker of endothelial damage. However, conventional enumeration methods are extremely challenging. We developed a novel, automated approach to determine CEC frequencies and tested this method on two groups of patients undergoing conventional (CAVR) versus trans-catheter aortic valve implantation (TAVI).
Methods:
CEC frequencies were assessed by a flow cytometric approach, including automated pre-enrichment of CD34 positive blood cell subpopulation and isotype controls. The efficacy and reproducibility of the CEC enumeration method was validated by spiking blood samples of healthy control donors with defined numbers of endothelial cells.
Results:
CEC frequencies were significantly higher in the TAVI group before (9.8 ± 4.1 vs. 5.5 ± 2.2, p = 0.019) and 1 h after surgery (13.4 ± 5.1 vs. 8.2 ± 4.1, p = 0.030) corresponding to higher Euroscore, STS score in higher risk patients from the TAVI group. Five days after surgery, CEC frequencies became significantly higher in the more invasive CAVR group (39.0 ± 13.0 vs. 14.3 ± 4.4, p < 0.001) compared to minimally invasive TAVI approach.
Conclusions:
The new flow cytometric approach might be a robust and reliable method for CEC enumeration. Initial results show that CEC frequency is a valid clinical marker for the assessment of pre-operative risk, invasiveness of surgical procedure and clinical outcome. Further studies are necessary to validate the practical clinical usefulness and the potential superiority compared to conventional markers.
