Discovering Coronary Artery Bypass Surgery – Step 3

Step 3: Cannulation, Cardiopulmonary Bypass, and Aortic Clamping under Extracorporeal Circulation (CPB)

Introduction

The third step of coronary artery bypass surgery involves establishing cardiopulmonary bypass under CPB or using off-pump techniques, such as the beating-heart approach. Surgeons sometimes prefer beating-heart techniques, which do not require CPB, cannulation, or aortic clamping.

Cannulation is a crucial step to ensure a stable and safe surgical environment, enabling the heart to be stopped while maintaining oxygenation and blood perfusion. During CPB procedures, complex equipment such as the heart-lung machine, along with cannulation and aortic clamping devices, is used to protect the myocardium and ensure hemostasis.

I. Surgery under CPB and the Heart-Lung Machine

1. Surgery under CPB

Extracorporeal circulation (CPB) involves temporarily diverting blood flow from the heart and lungs to an external circuit. This technique allows for the substitution of the heart’s pumping and the lungs’ oxygenation functions during cardiac surgeries that require a still heart.

The concept of CPB dates to 1884, developed by Von Frey and Gruber, with the first successful operation using this method performed in the United States on May 20, 1953.

The CPB system collects blood from the right atrium, oxygenates it through a membrane, and reinfuses it into the arterial system. This is made possible by the heart-lung machine. ¹

2. Heart-Lung Machine

The heart-lung machine replaces the functions of the heart and lungs during surgery. It consists of:

• Pump: Ensures blood circulation.
• Circuit: Transports oxygenated blood.
• Oxygenator: Oxygenates the blood outside the body.

A perfusionist manages this machine, ensuring proper blood circulation and oxygenation throughout the procedure.

III. Central Cannulation

1. Technique

To establish CPB, central cannulation is performed on the distal ascending aorta. The procedure begins by removing the adventitia at the cannulation site to prepare for cannula insertion.

A purse-string suture is then placed around the right atrium to secure the cannula.

Once inserted, the cannula is stabilized with a second purse-string suture, ensuring a safe connection to the CPB system.

2. Cardioxyl® and Corolene® for Purse-String Sutures

These sutures are used to create purse strings that allow for rapid closure and effective hemostasis during decannulation.

Non-absorbable sutures like Cardioxyl® 3/0 or 2/0 (coated polyester braid) or Corolene® (polypropylene monofilament) are recommended for their ability to withstand the high tension exerted during the procedure:

• Cardioxyl®: A non-absorbable braided suture coated with high-quality silicone, providing smooth passage through tissues and excellent tensile strength. Ideal for high-pressure sutures, such as on the ascending aorta, it is the most suitable braided suture in the Peters Surgical range for its excellent tissue glide.
• Corolene®: Used in practices requiring good sealing or when cannulation involves peripheral vessels. This non-absorbable suture also provides high knot security.

3. Closure of Cannulation Site

At the end of the procedure, cannulation sites must be carefully closed to prevent hemorrhagic complications. Non-absorbable braided sutures like Cardioxyl® 3/0 (coated polyester braid) are preferred for their high tensile strength.

In some cases, monofilament sutures like polypropylene (Corolene®) are used for their smoother passage, especially when the aorta is fragile or calcified.

III. Myocardial Protection through Cardioplegia

Once extracorporeal circulation is established, the ascending aorta is clamped to achieve reliable and effective cardioplegic myocardial arrest. The heart is temporarily stopped using either pharmacological methods or cooling techniques.

Various cardioplegia strategies exist, all aimed at protecting the myocardium during cardiac arrest to prevent irreversible damage.

Intrack® N10330v Aortic Clamps (Bahnson): Intrack® aortic clamps are used to block the aorta during cardiac arrest, ensuring reliable myocardial protection. They must remain stable to prevent risks of hemorrhage or inadequate myocardial protection.

These clamps are used exclusively with single-use inserts—Intrack® Insert N1017 4v (Ultra-length 66mm)—to protect the aortic wall, both externally (adventitia) and internally (media and intima). This is especially critical for patients with conditions such as Marfan syndrome or aortic aneurysms, where tissues are more fragile.

Conclusion

Cannulation and CPB setup are critical steps in performing coronary artery bypass surgery. Medical devices like non-absorbable sutures and aortic clamps, specifically designed to preserve the integrity of fragile tissues, are essential for patient safety while providing excellent myocardial protection. Solutions from Peters Surgical, such as Cardioxyl® and Corolene®, stand out for their unique properties, meeting surgeons’ requirements for successful operations.

CARDIOXYL®

INDICATIONS:

CARDIOXYL® sutures are intended for use in general soft tissue approximation and/or ligation, including use in cardiovascular, vascular and ophthalmic surgeries.

Class III Medical Device- CE 0459 – Manufacturer: Peters Surgical.

Read instructions carefully before use.

COROLENE®

INDICATIONS:

COROLENE® sutures are intended for use in general soft tissue approximation and/or ligation, including use in cardiovascular and vascular surgery, in ophthalmic surgery, in plastic surgery and in neurological surgery. COROLENE® sutures can be used for laparoscopic surgery and abdominal aorta surgery.

Class III Medical Device- CE 0459 – Manufacturer: Peters Surgical.

Read instructions carefully before use.

INTRACK® SURGICAL CLAMP

INDICATIONS : Vascular clamping : Suitable for veins and arteries – Performs efficiently on either diseased or normal vessels – Provides occlusion of atherosclerotic vessels without excessive closing forces – Minimizes intimal damage and fragmentation of atherosclerotic material – Can be clamped over indwelling catheters – Gastrointestinal clamping : Replaces bulky, rubber shod clamps – Cushion-design of inserts enables occlusion without crushing the bowel.

Class Ir Medical Device – Manufacturer :Vitalitec International, Inc. d/b/a Peters Surgical USA.

Read instructions carefully before use.

INTRACK® Insert

INDICATIONS : Do not resterilize and/or reuse the INTRACK® inserts. Resterilization and/or reuse may compromise the integrity of the device. This may lead to potential risks of failure of the device to perform as intended and/or cross-contamination associated with using inadequately cleaned and sterilized devices. Proper disposal of contaminated devices is required. Proper disposal of contaminated devices is required, including disposal of reusable clamps that are no longer acceptable for use. • It is possible to inadvertently pass a needle through the jaw insert, thereby attaching the insert to the suture line. Care must be taken to avoid pinching gloved finger between the insert and the clamp channel. INTRACK® Atraumatic removable insert, must be used exclusively with INTRACK® and Cygnet® surgical clamps

Class IIa Medical Device – CE 2797 – Manufacturer :Vitalitec International, Inc. d/b/a Peters Surgical USA.

Read instructions carefully before use.

SOURCES :

¹  Médipôle Lyon-Villeurbanne, Publication « Circulation extracorporelle CEC »

Circulation extracorporelle CEC – Médipôle Lyon-Villeurbanne