Noninvasive assessment of left and right internal mammary artery graft patency using transthoracic color Doppler echocardiography.

BACKGROUND: The aim of this study was to evaluate the patency of left and right internal mammary artery grafts respectively on the left anterior descending and right coronary artery by noninvasive transthoracic color Doppler echocardiography. METHODS: Thirty eight patients (34 males, 4 females, mean age 59 +/- 2 years), with a history of coronary artery bypass grafting for a total of 42 mammary artery grafts, were studied by means of color Doppler echocardiography at baseline and after vasodilation with dipyridamole infusion (0.56 mg/kg i.v. over 4 min). The evaluated echocardiographic parameters included: systolic (SPV) and diastolic peak velocities (DPV), systolic (SVI) and diastolic velocity-time integrals (DVI), and the DPV/SPV and DVI/SVI ratios. We also calculated the dipyridamole infusion to baseline ratio of the diastolic peak velocities (DPVdip/DPVbaseline), the index of internal mammary artery graft blood flow reserve and the percent DPV increment as an index of graft stenosis. RESULTS: On the basis of coronary angiography, two groups were selected: group A (36 mammary grafts) with patent grafts and group B (6 mammary grafts) with moderate or severe stenosis of the grafts. Group A had a predominant diastolic pattern with a DPV of 0.24 +/- 0.13 m/s, whereas group B had a predominant systolic pattern with a reduced DPV of 0.12 +/- 0.03 m/s (p < 0.01). Dipyridamole induced an increase in the DPV respectively of 86.8 +/- 64.4% in group A and 13.8 +/- 15.9% in group B (p < 0.001). Statistical analysis (Mann-Whitney test) revealed a significant difference between the two groups for the baseline DPV (p < 0.01), DVI (p < 0.05), DPV/SPV ratio (p < 0.005), DVI/SVI ratio (p < 0.05), and for the after dipyridamole infusion values: DPV (p < 0.0001), DVI (p < 0.005), DPV/SPV ratio (p < 0.001), and DVI/SVI ratio (p < 0.05). Multivariate analysis showed that the percent DPV increment, the DPVdip/DPVbaseline ratio and the baseline DPV were independent determinants of the stenosis as evaluated at angiography (beta = -0.38, p < 0.01; beta = -0.37, p < 0.01, and beta = -0.33, p < 0.05, respectively; cumulative r2 = 0.25, standard error 0.30 m/s, p < 0.005). CONCLUSIONS: The echocardiographic evaluation of the mammary grafts is a simple, noninvasive method for the assessment of the graft patency and of the functional status of the vessel. The percent DPV increment and baseline DPV were independent determinants of mammary graft stenosis.

Assessment of accessory atrioventricular pathways by Doppler myocardial imaging.

PURPOSE: The use of electrophysiologic studies (EPS) for the localization of accessory atrioventricular connections in Wolff-Parkinson-White syndrome (WPW) requires accurate evaluation of the site of bypass tract insertion. Doppler myocardial imaging (DMI) is a new ultrasound technique that allows the detection of abnormal and early regional myocardial depolarization. The purpose of this study was to identify an abnormal pathway site in WPW patients. METHODS: Twenty-one patients with ventricular preexcitation were studied by DMI. Two-dimensional color DMI, velocity maps, acceleration maps, and pulsed-wave applications were used. A subsequent diagnostic EPS was performed. The results of EPS were taken as the gold standard diagnostic procedure. Radiofrequency catheter ablation therapy was then performed on all patients. RESULTS: The anomalous pathway was detected by DMI in 16 (76%) of 21 patients (9 [90%] of 10 with left pathways and 7 [64%] of 11 with right pathways), with respect to results of the EPS. Pathway detection was better with pulsed-wave DMI (76%) with its higher temporal resolution as compared with M-mode velocity map (57%) and acceleration map (47%). In most of the patients with successful radiofrequency ablation, an immediate resolution of the abnormal ventricular depolarization occurred and was detectable by DMI. CONCLUSIONS: Our findings demonstrate the feasibility of DMI to assess the early ventricular contraction associated with atrioventricular accessory pathways. Therefore, DMI appears to be a clinically useful adjunct to noninvasive evaluation of abnormal myocardial depolarization in WPW and to evaluate the results after radiofrequency ablation, even though its accuracy is considerably better for left-sided accessory pathways than for right-sided ones.