Combined Antegrade-Retrograde Blood Cardioplegia does not Protect Right Ventricle Better than Either Technique Alone in Patients with Occluded Right Coronary Artery

Abstract

To study the hypothesis that combined antegrade-retrograde delivery of cardioplegia might overcome the limitations in myocardial protection of either technique alone, we compared the distribution of the different cardioplegic approaches by assessing myocardial cooling and evaluated the effects on right ventricular (RV) function in elective coronary artery bypass grafting (CABG) patients with occluded right coronary artery (RCA). In a randomized trial, 15 patients received exclusively antegrade (ante group), 14 patients received exclusively retrograde (retro group) and 15 patients received combined, alternating antegrade-retrograde (combi group) cold blood cardioplegia. Myocardial temperatures were measured at four sites in the heart. Right ventricular function was assessed by determining the ejection fraction (fast-response thermodilution) and preload-related RV stroke work in repeated measurements. Myocardial cooling was similarly uneven and the posterior wall of the RV remained above 20 degrees C after all three methods of delivering hypothermic (5-7 degrees C) cardioplegia. The RV ejection fraction and preload-related (right atrial pressure) RV stroke work decreased postoperatively similarly in all groups. The results suggest that combined antegrade-retrograde cold blood cardioplegia could not provide more homogeneous myocardial cooling or better RV recovery than either technique alone in three-vessel-diseased CABG patients with occluded RCA.

Right Ventricular Function After Coronary Surgery with or Without Bypass

“…Moreover, in patients with right coronary stenosis, retrograde cardioplegia was responsible for a reduction of the RVEF. Another randomized trial, including patients with right coronary thrombosis compared three groups of patients, receiving antegrade, retrograde, or combined antegrade–retrograde cold blood cardioplegia 12 . Myocardial cooling was similar in the three groups, and the RVEF decreased postoperatively in all groups.…”

“…The main limitation of this study was the absence of randomization: patients in the ONCAB group were more likely to have a lesion of the circumflex coronary artery and therefore, the number of grafts was higher in this group as the surgical exposure of the circumflex artery during OPCAB is more difficult. Anyhow, postoperative right ventricular dysfunction after ONCAB surgery is not related to the number of grafts 1 but is observed mainly in patients with RCA disease 12,16 …”

Ischemic Preconditioning in Cardiac Surgery

“…Inadequate RV protection may lead to unexpected low postoperative cardiac output despite good preservation of left ventricular function [54,104]. Current myocardial protective methods do not always offer adequate protection of RV, especially in patients with right coronary artery stenosis, neither antegrade nor retrograde cardioplegia delivery provides adequate protection of the right atrium and ventricle [54,105]. IP can thus be used as an additional protective means in the myocardial protection strategy of combined antegrade and retrograde delivery of cold blood cardioplegia.…”