Current Problems

Generally OPCAB is well tolerated; however, it may occasionally provoke arrhythmia and hemodynamic instability. The interruption of the flow of the right coronary artery is known to provoke some of these complications. The use of an intracoronary shunt when performing the anastomosis may attenuate this response. Most shunts are silicone tubes, 10 to 30 mm in length by 1.0 to 3.0 mm in diameter, designed to be inserted through the arteriotomy into the coronary lumen. The clinical value of shunts is questioned since they are cumbersome to use and, with respect to the shunt, blood flow through the shunt is only 30-50% of the native coronary flow.

Hemodynamic instability may be encountered with manipulation of the beating heart. The left anterior and diagonal arteries are relatively easy to approach. This is not true of the right coronary and circumflex arteries. Posterior grafting may require significant displacement of the heart but seems to be relatively well tolerated in most patients. To mitigate instability, the patient is placed in steep Trendelenburg position and rotated to the right.

OPCAB has significant advantages in patients for whom cardiopulmonary bypass and aortic manipulation presents an increased risk (renal, pulmonary, hepatic, and neurologic injury and/or insufficiency, aortic atheroma/calcification) and multivessel revascularization is required. The disadvantage of this approach is the technical difficulty of bypassing the posterior and lateral wall vessels and the need for a full midline sternotomy.

0 0

Post a comment