Importance of the Coronary Collateral Circulation for the Distribution of Anterograde and Retrograde Delivered Cardioplegic Solution in Aortocoronary Bypass Surgery: A Haemodynamic Study

Abstract

The importance of coronary collateral circulation for homogeneous distribution of anterograde and retrograde delivery of cardioplegia was evaluated in 36 patients undergoing myocardial revascularization. All patients had three-vessel coronary artery disease, with a stenosis of the right coronary artery of at least 80%. The patients were randomized into two groups: group A (n = 19) received anterograde delivered cardioplegic solution and group B (n= 17) received retrograde. Both groups were further subdivided depending on the pathology of the right coronary artery, as evaluated on preoperative coronary angiography. In group A, (n = 8) and group B₁ (n = 7) there was no visualization of collateral circulation from the left to the right coronary artery system, whereas in group A₂ (n =11) and group B₂ (n= 10) there was retrograde filling of the right coronary artery by collateral circulation. Right atrial pressure increased significantly (P< 0.05) in group A, and was elevated in group A₂. but not significantly (P= 0.07). By contrast, right arterial pressure decreased in groups B₁ and B₂. Analysis of the individual differences in the right atrial filling pressure showed a statistical significance between the two subgroups (group B₁ −1.0(0.5) versus group B₂ −1.8(1.1), P < 0.05), although the individual decrease of the right ventricular stroke work index was not significant. It is concluded that collateral circulation is important for an adequate distribution of anterogradely delivered cardioplegia and is also beneficial in cases of retrograde delivery.