Protective Effect of Antiapoptosis Potency of Prolonged Preservation by Desiccation Using High-Pressure Carbon Monoxide on Isolated Rabbit Hearts.

Heart transplantation has been widely accepted as a therapy for end-stage heart failure. Mitigation of ischemia-reperfusion injury by inhibiting the apoptotic process plays an important role in organ transplantation. Desiccation using high-pressure carbon monoxide (CO) is a new method of preserving donor hearts; however, its mechanism of antiapoptosis remains unclear. This study was intended to elucidate the efficacy and mechanism of preservation by desiccation for 18 hours using high-pressure CO on myocardial apoptosis. Rabbit heterotopic abdominal cardiac transplantation models were established. New Zealand rabbits were divided randomly into 3 groups: naive group (n = 16), HTK group (n = 16), and desiccation using high-pressure CO group (n = 16). The donor hearts of the naive group were transplanted immediately after being extracted. In the HTK group, the donor hearts were extracted and steeped in 4°C HTK cardioplegic solution for 18 hours and then transplanted; in the desiccation using high-pressure CO group, the donor hearts were extracted and exposed to a gas mixture (Po2 = 3200 hPa, Pco = 800 hPa) in the chamber before being preserved in a refrigerator at 4°C for 18 hours and then transplanted. Apoptotic cardiomyocytes were detected using TUNEL technique and histopathology was performed by hematoxylin-eosin staining. The expression of the ratio of Bcl-2/Bax and caspase-3 proteins was detected using the Western blot method. These findings suggest that compared with traditional HTK preservation, preservation by desiccation using high-pressure CO could alleviate rabbits' myocardial histopathology and apoptosis induced by ischemia-reperfusion injury through adjusting the ratio of Bcl-2/Bax protein expression, thus resulting in the reduction of expression of caspase-3.

Use of antispastic nicardipine and nitroglycerin (NG) cocktail solution increases graft flow during off-pump coronary artery bypass grafting.

AIM: NG solution composed of nicardipine and nitroglycerin is a new anti-spastic solution for arterial grafts. We investigated its efficacy on the left internal thoracic artery (LITA) during off-pump coronary artery bypass grafting (OPCAB). METHODS: The free flow of LITA in 41 OPCAB patients was measured. The patients were divided to four groups: LITA pedicle wrapped with normal saline (Group I, N.=10) or NG (Group II, N.=11); or in addition to wrapping, 2 cc NG (Group III, N.=10) or normal saline (Group IV, N.=10) injected into LITA. After 30 min, the distal end free flow and the graft flow by an ultrasound probe were measured. RESULTS: The free flow significantly increased in Group II (30.0±4.7 vs. 21.6±4.5 cc/min, P=0.007) and III (70.0±11.5 vs. 24.5±6 cc/min, P=0.001) but not in Group I (20.8±4.7 vs. 19.4±4.1 cc/min, P=0.33) or IV (35.8±7.5 vs. 29±9.2 cc/min, P=0.06) with significant differences between the Group III to all other groups (P=0.016-0.001). The graft flow by ultrasound probe was significantly higher in Group III (41.2±6.2 cc/min) than that in Group IV (24.1±3.1 cc/min, P=0.028). CONCLUSION: Use of NG solution for LITA graft preparation is a choice of antispastic protocol. NG solution used either topically or intraluminally significantly increases the blood flow of IMA grafts with the best effect obtained by intraluminal injection. The present study provides an additional anti-spastic method by using second generation of calcium antagonists and nitric oxide donor in coronary artery bypass surgery.