Rapid-freezing transmural cardiac biopsy drill

Area of Science:

• Cardiovascular Research
• Surgical Innovation
• Biomedical Engineering

Background:

• Accurate cardiac tissue sampling is crucial for diagnosing and understanding heart conditions.
• Existing methods may face challenges in speed, precision, and tissue preservation during extraction from the beating heart.

Purpose of the Study:

• To develop and evaluate a novel transmural cardiac biopsy drill for rapid, high-quality cardiac tissue acquisition.
• To assess the drill's efficiency in sampling from the beating canine left ventricle and the subsequent tissue preservation.

Main Methods:

• A transmural cardiac biopsy drill utilizing an air turbine (10,000 rpm) with 2.0 or 4.5 mm stainless steel bores was constructed.
• Vacuum aspiration transported biopsies into liquid nitrogen-chilled isopentane (-150°C) for rapid freezing.
• Biopsy speed, traversal time, freezing duration, and weight were measured.
• Myocardial blood flow was assessed using radionuclide-labeled microspheres.
• Light microscopy evaluated tissue damage.

Main Results:

• The drill successfully obtained transmural cardiac biopsies from the beating canine left ventricle in 0.14 ± 0.04 seconds.
• Biopsies were rapidly frozen, with large biopsies freezing in 1.46 ± 0.73 seconds and small biopsies in approximately 0.28 seconds.
• Average biopsy weights were 34 ± 14 mg (small) and 180 ± 71 mg (large).
• Light microscopy revealed minimal damage to cardiac muscle from the drill rotation.
• A 30% reduction in myocardial blood flow was observed within 0.5 cm of the 4.5 mm biopsy site.

Conclusions:

• The developed cardiac biopsy drill enables rapid, precise, and minimally damaging transmural cardiac tissue sampling.
• The device facilitates sampling at specific cardiac cycle points and ensures rapid freezing for histological analysis.
• Potential localized reduction in myocardial blood flow necessitates consideration in future applications.