Retrograde cardioplegia: Indication

Cardioplegia can be delivered using several routes:

• Through the aortic root after cross clamping anterograde down the coronary arteries
• Anterograde through isolated coronary artery ostia or prior coronary bypass grafts
• Retrograde through the coronary sinus to the coronary veins.

In a normal functioning heart, coronary arterial perfusion flows from aortic root through the coronary ostia and associated coronary arteries through small perfusing branches to the cardiac venous system. Like coronary arteries, there are several named coronary veins, the largest of which is the coronary sinus (confluence of great cardiac vein and vein of Marshall). The coronary sinus ostia lies in the right atrium on the inferior aspect of the interatrial septum between the inferior vena cava and the tricuspid valve. The coronary ostia can be cannulated manually with palpation or with either echocardiographic or fluoroscopic image guidance.

Retrograde cardioplegia is utilized in settings where:

1. There is an inability to deliver adequate cardioplegia anterograde, as in settings of severe aortic valve insufficiency or severe coronary arterial stenosis.
2. There are additional sources of perfusion distal to the aortic cross clamp, such as patent prior coronary arterial bypass grafts (i.e. internal mammary artery).
3. Prolonged aortic valve and/or root repairs as an alternative to selective coronary ostial cannulation.

Cannulation of the coronary sinus for retrograde cardioplegia may miss the anterior cardiac veins that often drain directly into the right ventricle. Because of this, isolated retrograde cardioplegia may be less protective for the right ventricle than combined anterograde/retrograde techniques.

There are risks of retrograde cardioplegia ranging from misalignment of the catheter leading to poor spread or leak into right atrium, coronary sinus rupture, or atrial dissection. Additionally, in patients with persistent left superior vena cava, retrograde cardioplegia may not achieve cardiac arrest as the left SVC communicates with the coronary sinus leading to systemic spillage of cardioplegia.

Updated Definition 2020:

Retrograde cardioplegia is the term used to refer to delivery of a cardioplegic solution via a catheter inserted into the coronary sinus for the purpose of myocardial protection during cardiac surgery. This is in contrast to antegrade cardioplegia, where the cardioplegic solution is delivered through the coronary arteries, most commonly by administration of the solution into the aortic root.

There are several indications for the use of retrograde cardioplegia. The administration of antegrade cardioplegia via the aortic root depends on a competent aortic valve. In the presence of aortic insufficiency, the delivery of cardioplegia via the coronary sinus can be indicated. Retrograde cardioplegia can also be indicated during aortic valve surgery. In patients with diseased coronary arteries, such as those who would present for coronary artery bypass grafting, or in patients with significant myocardial hypertrophy, retrograde cardioplegia can be indicated to more completely deliver cardioplegic solution to the myocardium. In many cases, retrograde delivery through the coronary sinus will be combined with antegrade delivery.