PERSISTENCE OF MAMMARY ARTERY BRANCHES AND BLOOD-SUPPLY TO THE LEFT ANTERIOR DESCENDING ARTERY

Background. Partial harvesting of the left internal mammary artery (LI MA) is a widespread technique used during minimally invasive coronary operations performed through a left anterior small thoracotomy. The in fluence of persisting LIMA branches was investigated to evaluate their effect on the blood now of the left anterior descending artery. Metho ds. Thirty patients, 15 with totally (group A) and 15 with partially ( group B) harvested LIMAs, were evaluated. All the patients underwent p ostoperative angiography, during which a now map of the LIMA was perfo rmed. The average peak velocity and the diastolic-to-systolic peak vel ocity ratio were recorded. The LIMA graft flow pattern was recorded in the proximal and distal thirds of the artery. Intramammary adenosine (12 to 14 mu g) was injected and the average peak velocities before an d after injection were calculated. Results. The average peak velocity was similar in both groups in the proximal and distal thirds of the LI MA (25 +/- 7 and 26 +/- 5 cm/sec, respectively, in group A versus 27 /- 5 and 25 +/- 5 cm/sec, respectively in group B; p = NS). The diasto lic-to-systolic peak velocity ratio was similar proximally (0.78 +/- 0 .3 in group A versus 0.69 +/- 0.3 cm/s in group B; p = NS), but not di stally (1.72 +/- 0.1 In group A versus 0.97 +/- 0.3 in group B; p < 0. 0005). The LIMA graft flow reserve was similar both proximally and dis tally (2.6 +/- 0.6 and 2.5 +/- 0.3 cm/s, respectively, in group A vers us 2.6 +/- 0.5 and 2.6 +/- 0.3 cm/s, respectively, in group B; p = NS) . Conclusions. The persistence of LIMA branches does not influence the blood flow of the left anterior descending artery after acute adenosi ne-induced myocardial hyperemia. If a left anterior small thoracotomy is used in left anterior descending artery direct revascularization, c omplete LIMA harvesting is not mandatory and depends on the personal p reference of the surgeon. (C) 1997 by The Society of Thoracic Surgeons .