Potent vasodilatory effect of fasudil on radial artery graft in coronary artery bypass operations

Vasodilatory Efficacy and Impact of Papaverine on Endothelium in Radial Artery Predilatation for CABG Surgery: in Search for Optimal Concentration

OBJECTIVE

The aim of this study was to compare the efficacy of two different papaverine concentrations (0.5 mg/ml and 2 mg/ml) for vasospasm prevention and their impact on endothelium integrity.

METHODS

We have studied distal segments of radial arteries obtained by no-touch technique from coronary artery bypass graft (CABG) patients (n=10). The vasodilatory effect of papaverine (concentrations of 0.5 mg/ml and 2 mg/ml) was assessed in vitro, in isometric tension studies using ex vivo myography (organ bath technique) and arterial rings precontracted with potassium chloride (KCl) and phenylephrine. The impact of papaverine on endothelial integrity was studied by measurement of the percentage of vessel's circumference revealing CD34 endothelial marker.

RESULTS

2 mg/ml papaverine concentration showed stronger vasodilatatory effect than 0.5 mg/ml, but it caused significantly higher endothelial damage. Response to KCl was 7.35±3.33 mN for vessels protected with papaverine 0.5 mg/ml and 2.66±1.96 mN when papaverine in concentration of 2 mg/ml was used. The histological examination revealed a significant difference in the presence of undamaged endothelium between vessels incubated in papaverine 0.5 mg/ml (72.86±9.3%) and 2 mg/ml (50.23±13.42%), P=0.002.

CONCLUSION

Papaverine 2 mg/ml caused the higher endothelial damage. Concentration of 0.5 mg/ml caused better preservation of the endothelial lining.

Fasudil Is an Effective Graft Vasodilator for Gastroepiploic Artery in Coronary Artery Bypass Grafting

OBJECTIVE

The gastroepiploic artery (GEA) has been used as an alternative arterial in situ graft for coronary artery bypass grafting (CABG). However, because of the large individual differences and the spastic nature of the GEA, caution has to be exercised during harvesting. We evaluated the usefulness of fasudil, a Rho kinase inhibitor, as a vasodilator for right GEA (RGEA) graft after harvesting, compared with the conventional agents papaverine and verapamil-nitroglycerin.

METHODS

Between June 2009 and January 2013, 30 patients with ischemic heart disease who underwent isolated CABG using RGEA graft were randomly assigned to fasudil (n = 10), papaverine (n = 10), or verapamil-nitroglycerin (n = 10) group. Fasudil (2.67 mmol/L), papaverine (1.0 mmol/L) mixed with heparinized blood, or verapamil-nitroglycerin (30 μmol/L each) was injected intraluminally into the RGEA graft after harvesting. Right GEA graft free flow (GFF), hemodynamic changes, and histopathology of RGEA were evaluated.

RESULTS

Intraluminal injection of fasudil increased GFF significantly (P < 0.001) and markedly from 41.5 ± 31.5 mL/min at baseline to 149.3 ± 46.7 mL/min after injection. Papaverine increased GFF (P < 0.001) from 40.0 ± 35.8 to 64.9 ± 33.7 mL/min, and verapamil-nitroglycerin also increased GFF (P < 0.001) from 38.8 ± 32.1 to 79.0 ± 35.2 mL/min. The GFF was significantly higher (P = 0.001) in the fasudil group than in the other two groups. Histopathologically, fasudil treatment markedly increased the diameter of RGEA graft, while maintaining integrity of the multiple elastic lamellae. Blood pressure did not change significantly after drug injection in all groups.

CONCLUSIONS

Fasudil is more potent than papaverine or verapamil-nitroglycerin in increasing GFF of RGEA graft for CABG.

Antispastic Management in Arterial Grafts in Coronary Artery Bypass Grafting Surgery

Arterial grafts have long-term patency superior to vein grafts but have a tendency to develop spasm that can lead to potentially life-threatening complications. A perfect antispastic protocol should include advanced surgical technique and adequate pharmacologic methods. All pharmacologic vasodilator drugs relax the vessel through specific mechanisms, and therefore, there is no perfect, single best vasodilator to prevent or treat spasm of the arterial graft against all mechanisms of contraction. One of the choices is to use a combination of pharmacologic vasodilators targeting different mechanisms of spasm to obtain the reliable and best effect.