An alternative application of sodium nitroprusside to overcome perioperative spasm of the internal thoracic artery

Objective: The internal thoracic artery (ITA) is currently the preferred co nduit for myocardial revascularization; however, perioperative vasospasm of the internal thoracic artery may cause morbidity. Pedicle preparation and pharmacological vasodilatory treatment vary greatly. This clinical study wa s performed in order to define the effectiveness of two different applicati ons of sodium nitroprusside as vasodilating agent. Methods: Eighty-six (86) consecutive patients whose left internal thoracic artery was mobilized only by one surgeon for elective coronary artery bypas s graft operations were randomly divided into two groups, The internal thor acic artery was allowed to bleed freely, and the flow was determined (flow 1). In group I (n = 42) 3 mg sodium nitroprusside in 10 ml of 5% dextrose s olution was sprayed with pressure on the pedicle with a thin 25 gauge needl e. In group II (n = 44) half of the solution was sprayed in the same manner , and the other half of the solution was injected into the pedicle in the p eriarterial tissue along the length of the pedicle. Free flows of the inter nal thoracic artery were registered before cardiopulmonary bypass (flow 2) and also just prior to performing internal thoracic artery anastomosis to t he left anterior descending artery (flow 3). With each measurement hemodyna mic parameters and the time between measurements were recorded. Results: No statistically significant differences were found between the gr oups in respect to sex ratio, age, body surface area, heart rate 1 and 2, m ean arterial pressure 1 and 3. There was no significant difference in the i nitial flow among groups. Significant differences were noted in the second flow measurement (P < 0.05) and in the third flow measurement (P < 0.01) be tween two groups. For each group there was a significant increase in flow f rom flow 1 to flow 2 and from flow 2 to flow 3 (P < 0.02). Conclusion: Sodium nitroprusside injection to the pedicle provides a better flow than simple spraying of the same agent. (C) 2001 The International So ciety for Cardiovascular Surgery. Published by Elsevier Science Ltd. All ri ghts reserved.