Encyclopedia of Experiments: Biology
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Suggested Video
Ex Situ Heart Perfusion - ConceptTranscript
After removing any excess tissue around the left atrium, use a 3-0 polypropylene suture to place a purse-string suture around the left atrial orifice. Suture and close the inferior vena cava with a 3-0 polypropylene suture. Place the left atrial cannula into the left atrial orifice, and secure the cannula with a snare. Place the left atrial cannula over the silicone-membrane-embedded magnet of the apparatus, taking care that the magnet and the corresponding metal ring in the left atrial cannula are properly engaged.
Attach the aorta to the aortic cannula embedded in the silicone membrane, and use a silk tie to secure the aorta around the cannula. Trim the aorta to achieve a proper lie without tension or kinking and increase the aortic pump speed to about 1,600 RPM, and gently squeeze the ventricles to de-air the heart. The remaining air in the aortic root will be ejected through the innominate and subclavian branches.
Connect the aortic purge line to the innominate artery, and secure the connection with a silk tie. Snare the left subclavian artery orifice with a silk tie, and secure the closure with a snare and a snap. Place a 5-French introducer sheath through the orifice of the subclavian artery, adjusting the length and orientation of the catheter so that the catheter does not interfere with the aortic valve function.
Adjust the aortic pump speed to reach a mean pressure of 30 millimeters of mercury to start the perfusion in the non-working Langendorff mode. The appearance of a dark, deoxygenated perfusate in the pulmonary arterial line indicates the re-establishment of coronary flow.
Turn the heat exchanger to 38 degrees Celsius to warm the perfusate, and use a blood gas analyzer to check the dissolved gas status, adjusting the gas mixture to the appropriate parameters. After an hour in non-working mode, enter a suitable left atrial pressure in the desired left atrial pressure section of the software, and initiate the feedback loop.
The activated working mode will appear as a green button and the left atrial pump speed will automatically increase and decrease to reach and maintain the selected left atrial pressure.
