Laser fluorescence angiography reveals perfusion defects in retrograde cardioplegia

Abstract

Adequate perfusion of the right ventricle with retrograde cardioplegia has always been questioned. However, clinical studies suggested sufficient protection and, up to now, intraoperative assessment of cardioplegia distribution has been difficult. As a pilot study in 14 patients, we used indocyanine green laser fluorescence angiography (ICGLA) to assess vascular and myocardial perfusion of different areas of the right anterior ventricular wall. Regions of interest were analyzed quantitatively using a new software package. ICGLA allowed rapid and reliable visualization of cardioplegic flow and distribution. Retrograde cardioplegia revealed perfusion defects in the territory of the right anterior cardiac veins when compared to antegrade delivery and to areas close to the left anterior descending vein(s), confirmed by quantitative analyses of maximal fluorescence intensity. Five patients were excluded from quantitative analyses. The learning curve, pitfalls, limitations and special image details are described. A larger study is necessary to examine the relevance of perfusion defects to metabolic changes in affected myocytes and to global right ventricular function.