A new antispastic solution for arterial grafting: Nicardipine and nitroglycerin cocktail in preparation of internal thoracic and radial arteries for coronary surgery

Objective: Antispastic protocols for arterial grafts are important in arterial grafting for coronary artery bypass grafting surgery. We designed a new nicardipine and nitroglycerin cocktail that is composed of a second-generation dihydropyridine calcium antagonist, nicardipine and nitroglycerin (30 mmol/L), and examined its effect in human internal thoracic and radial arteries. Methods: Human internal thoracic (n = 86) and radial (n = 74) artery segments from 72 patients undergoing coronary artery bypass grafting were studied. Relaxation against 3 classic vasoconstrictors (potassium chloride, thromboxane A(2) mimetic U46619, and alpha-adrenoceptor agonist norepinephrine) and prophylactic effect on contraction against these vasoconstrictors were examined. The effect of the nicardipine and nitroglycerin cocktail on the endothelial function in internal thoracic and radial arteries was studied in response to acetylcholine. Results: Nicardipine and nitroglycerin induced almost full relaxation (92.2% +/- 4.7% to 97.9% +/- 1.0%, P < .001 in internal thoracic arteries and 95.4% +/- 1.9% to 96.7% +/- 3.3%, P < .001 in radial arteries, n = 6-8) against 3 vasoconstrictors with significant prophylactic effect on contraction (maximal contraction was depressed to 32.5% to 76.4%, P < .05 or P < .001, and EC50s were increased to 5 to 42-fold more, P < .01). After treatment with the nicardipine and nitroglycerin cocktail, the acetylcholine-induced relaxation was unchanged (P > .05). Conclusion: The use of the nicardipine and nitroglycerin cocktail provides a new antispastic protocol that has rapid onset, full relaxation, and excellent prophylactic effect against all known mechanisms of vasospasm and maximally protects the endothelial and smooth muscle function of the internal thoracic and radial arteries. The cocktail is therefore expected to provide a new method in treating grafts in coronary artery bypass grafting with the best antispastic effect and protection of the graft.