Assessment of the permeability of left internal mammary artery graft patency by transcutaneous Doppler flow velocity analysis

Objective. To analize the features of Doppler flow velocity curve of left i nternal mammary artery by-pass grafts in relation with their permeability a s assessed by selective angiography. Methods. Twenty-five consecutive patients with a left mammary artery graft were studied by angiography and transcutaneous Doppler technique. From the Doppler tracings, peak velocity and time-velocity integral of the systolic and diastolic components were determined. Patency of the graft and the char acteristics of the distal native coronary artery were evaluated at angiogra phy. Results. Doppler flow signal was obtained in 23 (92%) of 25 analyzed patien ts. The graft was angiographically patent in 17 (68%) of 25 patients; in 15 (88%) of them the Doppler flow velocity signal was mainly diastolic and in only 2 (12%) it was predominantly sistolic. In 8 (32%) of the 25 patients the graft was angiographically occluded, 6 (75%) of these patients showing a predominantly systolic Doppler signal, while the remaining 2 (25%) patien ts were those in whom the signal could not be elicited. Sensitivity and spe cificity of a predominantly diastolic Doppler flow pattern for the presence of graft patency was 88% and 100% respectively, with a predictive positive value of 100% and a negative one of 80%. Conclusions. Doppler flow velocity pattern of internal mammary artery by-pa ss grafts is related with patency of the graft, the presence of a predomina ntly diastolic curve being highly indicative of a patent graft.