Comparison of ultrasonically activated scalpel and traditional technique in radial artery harvesting; an electron microscopic evaluation.

OBJECTIVE: Use of the radial artery (RA) as a conduit in coronary artery bypass grafting (CABG) has become increasingly popular in recent years. The aim of this prospective randomized study is to determine how the endothelial wall and blood flow of RA are differently affected with the usages of ultrasonic scalpel and conventional electrocautery in addition to effects of hypothermia and storage solutions. Histopathologic study was achieved by electron microscope to evaluate endothelium of the grafts. METHODS: Between 2008 and 2009, 182 patients with coronary artery diseases were operated for coronary artery revascularization. The radial arteries were harvested for 40 of these patients and divided into two groups depending on the use of the ultrasonic cautery (UC) (n=20) and the high-frequency electrocautery (EC) (n=20). Patients were divided into two subgroups according to the storage media of the graft. RA was preserved in situ at room temperature (Group 1) and normothermic organ bath (NOB) (Group 2). Harvesting time, use of hemostatic clips, frequency of spasm, in situ free flow, temperature and endothelial damage were compared between the two groups. Statistical analysis was performed using one-way ANOVA, Friedman and unpaired t tests. RESULTS: In all groups, blood flows were significantly decreased as parallel to the local temperatures. Second and third phase flows were similar in group EC1 and UC1 (p>0.05). Free flow was increased in group UC+NOB when comparing with only EC group (60.4±9.83 ml/min and 40.8±7.50 ml/min, p<0.001), whereas the graft preparing time "t2" was shorter in group EC than UC (10.9±2.42 min and 15.2±1.31 min, p<0.01). Nonetheless scoring of the groups in terms of endothelial cell structure and mitochondrial morphological changes did not show any significant difference. CONCLUSION: If endothelial integrity of the RA can be preserved along with the application of systemic temperature (NOB), regardless of harvesting technique, it provides better flow rates.

Effects of normothermic organ bath and verapamil-nitroglycerin solution alone or in combination on the blood flow of radial artery.

OBJECTIVE: Radial artery pedicle tissue cooling during harvesting is one of the major causes of vasospasm. We aimed to compare the effects of the pedicle rewarming method, normothermic organ bath, and one of the most preferred topical antispasmodic agents, verapamil-nitroglycerin solution alone or in combination on the blood flow of radial artery. METHODS: Consecutively randomized patients (n=80) undergoing coronary bypass were organized as four equal-sized groups. Effects of normothermic organ bath and topically performed verapamil-nitroglycerin solution alone or in combination on the blood flow of radial artery were investigated. In the control group no antispasmodic treatment was performed. Free flows were measured at three stages: as initial flow after minimal distal harvesting, post-harvesting flow after total harvesting, and post-treatment flow following a waiting period after the application of the antispasmodic protocol. At each stage, pedicle and esophageal temperatures were also recorded. RESULTS: Radial artery pedicle temperatures decreased significantly during harvesting in all groups (p<0.001). Normothermic organ bath, topical verapamil-nitroglycerin solution treatment, and their combination increased flow significantly (p<0.001, from 40.3+/-10.48 ml/min to 64.3+/-18.8 ml/min, from 38.9+/-13.91 ml/min to 62.75+/-15.23 ml/min, from 41.4+/-11.19 ml/min to 75.4+/-15.32 ml/min, respectively). The differences between the initial and post-treatment flows were not significant in the combined procedure group (p>0.05), whereas the initial levels were not reached in the post-treatment flows (p<0.05) in the normothermic organ bath and verapamil-nitroglycerin groups. CONCLUSIONS: Hypothermia plays an important role in radial artery vasospasm. Normothermic organ bath and verapamil-nitroglycerin solution alone or in combination relieve spasm of radial artery.

Normothermia is the key for the treatment of internal thoracic artery spasm.

BACKGROUND: Free flow of the internal thoracic artery decreases commonly after harvesting because of spasm. Tissue heat loss is inevitable during surgery. The aim of this study was to compare the internal thoracic artery pedicle rewarming method with topical papaverine applications in different thermal conditions. METHODS: Patients (n = 120) were organized in to 6 equally sized groups. The effects of topical papaverine application at room temperature, topical heated papaverine (at 37 degrees C) application, internal thoracic artery pedicle storage in normothermic conditions, pedicle storage in normothermic conditions combined with topical papaverine application, and pedicle storage in normothermic conditions combined with topical heated papaverine application were investigated. In the control group, no treatment was applied and the pedicle was stored in room temperature conditions. We measured internal thoracic artery free flows at 3 stages: at the initiation of harvesting, after total harvesting, and after antispasmodic treatment. Durations of the stages were recorded. At each stage hemodynamic parameters, tissue and core temperatures were also monitored. RESULTS: Internal thoracic artery pedicle temperature significantly decreased simultaneously with the free flow after the harvesting procedure. Recovery of the physiologic temperature state, provided by storing the internal thoracic artery pedicle in normothermic conditions, improved the flow and increased the efficiency of topically applied papaverine on the vasospasm of the internal thoracic artery. CONCLUSION: Topical application of heated papaverine itself does not warm pedicle tissue, but papaverine efficiency increases when the pedicle is stored in normothermic conditions. Preserving internal thoracic artery pedicles in normothermic conditions can be the preferred treatment for spasms.