Correlation between Doppler, Manual Morphometry, and Histopathology Based Morphometry of Radial Artery as a Conduit in Coronary Artery Bypass Grafting.

Background. Long-term graft patency is the major factor impacting survival after coronary artery bypass grafting. Arteries are superior in this regard. Radial artery is considered the second best conduit after internal mammary artery. Several studies have shown excellent radial artery patency. We evaluated the morphologic characteristics of radial artery by three modalities, (i) preoperative Doppler ultrasound, (ii) intraoperative manual morphometry, and (iii) postoperative histology-based morphometry, and compared these with the aim of validating Doppler as a noninvasive test of choice for preoperative assessment of radial artery. Methods. This was a prospective study involving 100 patients undergoing coronary artery bypass grafting in which radial artery was used. The radial artery was assessed using preoperative Doppler ultrasound studies, intraoperative morphometry, and postoperative histopathology and morphometry. The morphometric measurements included (i) luminal diameter, (ii) intimal and medial thickness, and (iii) intima-media thickness ratio. Results. Using Bland-Altman plots, there was a 95% limit of agreement between the preoperative Doppler measurements and the postoperative histopathology and morphometry. Conclusion. Doppler ultrasound is an accurate screening test for evaluation of radial artery, in terms of intimal/medial thickness and luminal diameter as a conduit in coronary artery bypass grafting and has been validated by both morphometric and histopathology based studies.

Is radial artery Doppler scanning mandatory for use as coronary bypass conduit?

BACKGROUND: Screening of the radial artery prior to harvesting as a conduit for coronary bypass may be performed clinically by the Allen test or by Doppler ultrasound. In a developing country like ours, the use of resources for Doppler studies may be questioned when Allen tests lead to a low rate of clinical sequelae. However, the rare occurrence of hand ischemia may be devastating and could justify the routine use of Doppler screening. This study aimed to address this question. METHODS: One hundred patients undergoing elective coronary artery bypass grafting were screened by the modified Allen test and Doppler ultrasound for suitability of use of a radial artery conduit. After harvesting, proximal and distal segments of the radial artery were subjected to histopathological examination. RESULTS: Of the 95 patients deemed suitable for radial artery grafting, 6 had mild calcification on Doppler ultrasound and 9 had calcification on histopathological examination. While Doppler showed atherosclerosis in 9 patients, only 6 had histopathological evidence of this (false-positive rate 3%). Of the 6 patients with histopathologic evidence of atherosclerosis, 2 were negative on Doppler (false-negative rate 2%). CONCLUSION: Routine preoperative Doppler screening of the radial artery in the setting of limited resources is not justified. On the other hand, the time-tested Allen test which is easy to perform, interpret, and reproduce can be safely used as the sole screening test to harvest the radial artery.