Radial artery frequently develops spasm and requires vasodilator therapy during coronary artery bypass graft surgery (CABG). Levosimendan was recently shown to oppose 5-hydroxytryptamine-induced contraction of radial artery (RA) grafts. The aim of the present study was to explore whether levosimendan retains its vasodilatory capacity following in vitro pre-incubation of RA segments with the inodilator. A possible cumulative effect of the drug in human platelets was also studied. Human isolated RA segments were pre-incubated in 0.16 lmol ⁄ L levosimendan containing solution or in 0.9% NaCl, Bretschneider, 5% albumin and a 5% human serum protein solution (Biseko) as controls for 45 min. Contractions were induced by three consecutive administrations of 5-hydroxytryptamine (0.31 lM) 45, 90 and 120 min. after exchanging the pre-incubation solutions with Krebs-Henseleit solution, uniformly. Receptor-independent contractions (KCl, 80 mmol ⁄ L), endothelium-dependent (acetylcholine, 1 lmol ⁄ L) and independent relaxations (papaverine, 100 lmol ⁄ L) were also investigated. Washed human platelets were pre-incubated with levosimendan (0.06 lmol ⁄ L) for 2 or 15 min. and aggregated with thrombin (0.1 IU ⁄ mL). Contractions of RA grafts induced by 5-hydroxytryptamine were significantly smaller 45 min. and 90 min. after the replacement of levosimendan with Krebs-Henseleit solution. Biseko solution also decreased the contraction of the graft at 45 min. Contractions did not change in time following the pre-incubations of radial arteries with 0.9% NaCl, Bretschneider and 5% albumin solutions. The grafts remained intact as assessed by their maximum contractions and endothelium-dependent and endothelium-independent relaxations at the end of the investigations. Platelets revealed larger antiaggregatory effect to levosimendan following the enhancement of the incubation time. Results indicate that the antispasmodic and anti-aggregatory effects of levosimendan cumulate in the vascular tissue and in platelets. The storage of RA with the inodilator before implantation may help to prevent the intraoperative spasm of the graft and also thrombotic occlusion during CABG surgery.

Levosimendan is a novel inodilator drug developed for the treatment of heart failure. The possible vasodilating property of the drug in human coronary artery bypass grafts was investigated. Isometric tensions of the left internal thoracic artery (LITA, n = 8) as well as the proximal and distal segments of the radial artery (RA, n = 8 and 8) were measured in isolated organ baths. Concentration-relaxation curves for levosimendan (0.009-1.14 micromol L(-1)) were obtained against 5-hydroxytryptamine (5-HT; serotonin, 0.002-9.3 micromol L(-1))-induced contractions. 5-HT-induced contraction of LITA was considerably smaller than that of the proximal and distal RAs. Levosimendan relaxed the grafts in the following order of calculated maximum efficacies (E(max)): LITA > proximal RA > distal RA (LITA 100.3+/-16.2% of 5-HT-induced maximum tension, proximal RA 86.9+/-8.6%, distal RA 59.4+/-17.5%, P < 0.05 LITA vs distal RA). The potency values of levosimendan, expressed as the negative logarithm of 50% effective concentrations (pD(2)), were comparable in the three bypass grafts (LITA -6.52+/-0.44 log mol L(-1), proximal RA -6.60+/-0.49 log mol L(-1), distal RA -6.85+/-0.45 log mol L(-1)). The results suggest that levosimendan is an effective vasorelaxant of conduit bypass grafts and may serve as a new therapeutic tool, especially in the case of LITA and proximal RA grafts, for relieving perioperative spasm and subsequent graft failure.

Our results suggest that storage of radial artery in Biseko colloidal solution before coronary artery bypass grafting decreases the sensitivity of the graft to vasoconstriction, thereby decreasing the risk of intra/perioperative graft failure.

Aortic dissection is a life threatening cardiovascular catastrophy. Its incidence estimated to 5-6 cases per 100,000 patients/year. The intimal tear happens at the ascending aorta in Type A, meanwhile at the aortic isthmus in Type B, but entry point may develop anywhere alongside the entire aorta. All types may affect a short aortic segment resulting in a localized false aneurysm, others separate the intimal layer at longer extension down to the visceral segment and far beyond to the femoral arteries. Dissection of orifices of side branches may lead to cerebral, upper extremity, spinal, visceral, renal and lower extremity malperfusion. These complications beyond the aortic rupture contribute significantly to high mortality of dissection. Today, first line treatment option in Type A dissection is surgery, but it can be endovascular or medical in Type B dissection. However, awareness of surgical procedures in this field remains inevitable. In this paper we summarize the surgical options for distal malperfusion affecting spinal, visceral, renal and lower extremity circulation.

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