Coronary flow patterns in circumflex and anterior descending coronary arteries evaluated with transesophageal echocardiography in normal vs aortic patients

Transesophageal echocardiography analysis of Doppler signal of coronary flow in the left main and left anterior descending arteries is much easier than in the circumflex artery because of the perpendicular course of the latter vessel. Even though multiplane transesophageal echocardiography facilitates Doppler examination, the characteristics of coronary flow pattern in the circumflex artery and its relation with hemodynamic and echocardiographic variables have not been studied yet. In this study we comparatively assessed the coronary flow pattern in the left anterior descending and circumflex arteries through multiplane transesophageal echocardiography in patients with normal heart and in patients with cardiac hypertrophy. We examined 10 patients with aortic stenosis (Group 2) before and immediately after aortic valve replacement by using intraoperative multiplane transesophageal echocardiography. Systolic (SPV) and diastolic (DPV) coronary peak velocities and velocity integrals (SVI; DVI) were evaluated in the proximal part of left anterior descending and circumflex arteries and compared with those recorded in 10 subjects without valvular or coronary diseases (Group 1) who required surgery because of abdominal aortic aneurysm or obstructive peripheral arterial disease. In Group 1 DPV and DVI were similar in the two vessels, while SPV and SVI were significantly lower in left anterior descending vs circumflex artery. In Group 2 DVI was similar in the two branches, while DPV was higher in the left anterior descending artery. Six patients presented reversed flow in the left anterior descending artery in Group 2, and antegrade flow in the circumflex artery. For this reason SPV and SVI in the left anterior descending artery were negative and significantly lower in comparison with the circumflex artery values. Comparisons between the two groups showed that systolic flow velocities were significantly lower in the aortic group. A significant correlation was found between SPV of left anterior descending artery and septal thickness and aortic gradient in Group 2. Postoperatively SPV and SVI increased in both vessels in Group 2. In conclusion, the systolic component of coronary flow pattern is higher in the circumflex than in the left anterior descending artery in normal subjects, while the diastolic component is similar in both vessels; in aortic stenosis differences between the two vessels are more marked. Systo-diastolic distribution of coronary flow is related to the anatomic course of each vessel since the systolic flow in the left anterior descending artery is dependent on the thickness of interventricular septum in the normal and hypertrophic heart.