Acellular Tissue Engineered Vessels as Coronary Artery Bypass Grafts

Area of Science:

• Biomaterials Science
• Cardiovascular Surgery
• Regenerative Medicine

Background:

• Autologous vessels like internal mammary arteries and saphenous veins are standard for coronary artery bypass graft (CABG) surgery.
• Limited availability or poor quality of these native vessels can restrict revascularization options for patients.
• There is a critical need for alternative, reliable conduits for CABG procedures.

Purpose of the Study:

• To evaluate the efficacy and durability of a small diameter acellular tissue-engineered vessel (sdATEV) as an alternative CABG conduit.
• To assess the patency, diameter changes, and host integration of the sdATEV in a primate model.
• To investigate the cellular and molecular mechanisms underlying sdATEV remodeling and function.

Main Methods:

• A 3.5 mm sdATEV was implanted in the right coronary artery (RCA) of adult baboons (n=5) for CABG.
• Longitudinal assessment of vessel patency, diameter, and cardiac function using computed tomography angiography.
• Histological analysis and spatial transcriptomics were employed to examine sdATEV recellularization and gene expression.

Main Results:

• All implanted sdATEVs demonstrated sustained patency over a 6-month study period.
• Computed tomography angiography revealed gradual remodeling of the distal sdATEV diameter to match the native baboon RCA.
• Histology and transcriptomics confirmed recellularization by host endothelial and smooth muscle cells, with gene expression patterns resembling the native RCA.

Conclusions:

• The small diameter acellular tissue-engineered vessel (sdATEV) shows promise as a durable and effective alternative conduit for coronary artery bypass graft (CABG) surgery.
• Host cell ingrowth from the native coronary artery appears to regulate the diameter remodeling of the sdATEV.
• These findings support the potential of sdATEVs to overcome limitations associated with autologous vessel availability in CABG.