Effects of papaverine and glycerylnitrate-verapamil solution as topical and intraluminal vasodilators for internal thoracic artery.

BACKGROUND: Arterial spasm is described as an event occurring after left internal thoracic artery (LITA) harvesting. Many vasodilators have been used to treat or prevent LITA spasm. The aim of this study is to compare the effects between glyceril-trinitrate/verapamil (GV) solution and papaverine to treat LITA spasm and to determine the best delivery method. METHODS: One hundred consecutive ischemic patients were randomly assigned to three groups: group GV (n = 34, GV solution), group P (n = 33, papaverine), or group C (n = 33, normal saline). In each patient, pedicled LITA was harvested, thereafter sprayed with the randomized solution, and covered with a sponge. Fifteen minutes after heparin administration, LITA was distally divided; flow per minute was calculated after measuring the free flow for over 15 seconds; this is named "topical free flow." Then, the vasodilator was injected intraluminally and free flow per minute was measured; this is called "intraluminal free flow." RESULTS: Analysis of variance was applied to detect differences among groups; paired-sample t test was used for LITA topical free flow versus intraluminal free flow within single groups. Mean LITA free flows were as follows: group GV, topical free flow = 38.6 +/- 25.2 mL/min versus intraluminal free flow = 58.8 +/- 29 mL/min (p < 0.0001); group P, topical free flow = 45.4 +/- 38.9 mL/min versus intraluminal free flow mL/min (p < 0.0001); group C, topical free flow = 31.6 +/- 19.9 mL/min versus intraluminal free flow = 34 +/- 19.8 mL/min (p = 0.14). Topical free flow difference among the three groups was not statistically significant (p = 0.1); intraluminal free flow difference was statistically significant (p = 0.001). Intraluminal free flow in group GV and in group P were higher than intraluminal free flow in group C (p = 0.004 and 0.001, respectively). Intraluminal free flow of group P was higher than that of group GV; this difference did not reach statistical significance (p = 1.00). CONCLUSIONS: Glyceril-trinitrate/verapamil solution and papaverine are able to treat the spasm and increase the flow of the LITA, when they are used intraluminally. When used topically, these vasodilator agents do not ensure an optimal free flow.

L-arginine effects on myocardial stress in cardiac surgery: preliminary results.

BACKGROUND: L-arginine in addition to cardioplegia stimulates the release of nitric oxide and increases coronary blood flow, decreasing platelet activation and leukocyte adhesion. The aim of our study was to determine the feasibility and the efficacy of the addition of L-arginine to antegrade and retrograde blood cardioplegia in reducing myocardial damage and stress. METHODS: Twenty-eight consecutive patients who underwent coronary artery bypass grafting were randomized to receive 7.5 g of L-arginine in 500 ml of cardioplegic solution. To assess safety of use of L-arginine, hemodynamic evaluation was performed before sternum opening, at sternum closure, and 1 hour after arrival in the intensive care unit to measure cardiac index, systemic and pulmonary vascular resistances, and pulmonary capillary wedge pressure. Moreover, transesophageal echocardiography was performed to assess myocardial contractility. To determine the effects on myocardial stress, blood samples were taken from the retrograde coronary sinus catheter for lactate, interleukin (IL)-2 receptor, IL-6 and tumor necrosis factor (TNF)-alpha levels. Serum samples (preoperatively, 2, 18 and 42 hours after aortic cross-clamping removal) were also analyzed to measure creatine phosphokinase, creatine kinase-MB mass, cardiac troponin T, platelets, and leukocytes. RESULTS: We found statistical differences for IL-2 receptor, IL-6, TNF-alpha, platelets and leukocytes, in favor of the treated group, and decreasing trends in creatine kinase-MB mass and troponin T levels. CONCLUSIONS: The present study shows the positive effects of the addition of L-arginine to cardioplegia. Reduced IL-2 receptor, IL-6 and TNF-alpha indicate a decrease in myocardial stress. Safety of Larginine is related to lower values of systemic vascular resistances and pulmonary capillary wedge pressure observed in group A postoperatively that could improve the patient's outcome in terms of a reduced need for inotropic support. Moreover, the decrease in platelet and leukocyte count in the treated group might express a reduced no-reflow phenomenon and a better reperfusion, limiting endothelial injury from oxygen radical production.