Laser Doppler imaging of myocardial perfusion during coronary bypass surgery

Laser Doppler perfusion imaging has been used to assess the myocardium perfusion on the arrested heart during bypass surgery. Twenty-two patients undergoing coronary artery bypass grafting, including usage of the left internal thoracic artery, were included in the study. The anticipated perfusion increase following declamping of the internal thoracic artery was investigated by mapping areas at the size of 10cm x 11cm, (n = 11) and 7cm x 5cm (n = 11). The larger images allowed quantification of blood flow in different regions of the myocardium. The size of the affected area was 32.2 +/- 12.9 cm(2) with a total increase of 3.17 +/- 0.75 a.u. (range 0.10 a.u.). Corresponding values for areas surrounding the vessels and areas defined as the larger vessels in the myocardium were 29.0 +/- 10.9 cm(2) (2.85 +/- 0.57 a.u.) and 3.5 +/- 2.8 cm(2)(6.78 +/- 0.18 a.u.), All subjects but two showed a substantial blood flow increase (>2 a.u.) after release of the clamp. Six subjects had a total increase of at least 4a.u. Correlation analysis between areas including various number of sites showed an r = 0.91 (p < 0.0001) or better. In conclusion, laser Doppler perfusion imaging can easily be used intraoperatively in conjunction with bypass surgery. It enables immediate assessment of both the increase and spatial distribution of myocardial perfusion following declamping of an arterial graft.