Cardiopulmonary bypass as a cause of free radical-induced oxidative stress and enhanced blood-borne isoprostanes in humans

Free radicals are believed to be involved in postsurgery-related complications. We studied whether cardiopulmonary bypass (CPB) operation has any immediate impact on the initiation of oxidative stress and inflammatory response by measuring isoprostanes and prostaglandin F2alpha during and 24 h following CPB. The levels of 8-iso-PGF2alpha (a major F2-isoprostane and biomarker of oxidative stress) and 15-keto-dihydro-PGF2alpha (a major metabolite of PGF2alpha and biomarker of inflammatory response) were measured in frequently collected plasma samples before, during, and up to 24 h postsurgery in 21 patients. 8-Iso-PGF2alpha levels significantly increased within 3 min (p <.0001) and continued until 50 min (p <.0001) during CPB. On the contrary, no significant increase of inflammatory response indicator, 15-keto-dihydro-PGF2alpha was found during and up to 24 h postoperatively. These findings establish an increased free radical-induced oxidative stress activity rather than inflammatory response after CPB.

Oxidative Stress and Changes in α- and γ-Tocopherol Levels during Coronary Artery Bypass Grafting

We studied whether cardiopulmonary bypass (CPB) has any immediate impact on the initiation of antioxidative defenses in the body by measuring F(2)-isoprostanes and alpha- and gamma-tocopherol, respectively. 8-iso-PGF(2alpha) levels increased significantly within 3 minutes and until the end of CPB. alpha-Tocopherol levels increased gradually at 20 min during CPB and continued until 6 hours after CPB. gamma-Tocopherol levels followed a similar fashion at the end of CPB. 8-iso-PGF(2alpha) and tocopherol levels kept at basal level 12 and 24 hours post CPB. These findings suggest that an increased free radical-induced oxidative stress together with a gradual appearance of antioxidative defense system during and after CPB.

Protective Effects of Betanin against Oxidative Stress in a Peripheral Artery Vasospasm Model in Rat

Objective: The aim of this study is to determine protective/modulatory effects of betanin in a femoral artery vasospasm model in rats. Materials and Methods: Sprague-Dawley rats were divided into three groups. Group 1: sham (n = 7), group 2: vasospasm model only (n = 7), group 3: postoperative betanin treatment in the vasospasm model (n = 7). 100 mg/kg betanin was administered orally to group 3 for 7 days, postoperatively. Peripheral blood malondialdehyde (MDA) and nitric oxide (NO) levels were measured for the quantification of oxidative stress, lumen diameter and wall thickness of femoral artery segments were determined to assess vasodilator effects of betanin. Results: Femoral artery vasospasm formation significantly increased both MDA (13.54 ± 3.09 mmol/mL) and NO levels (0.61 ± 0.06 µmol/mL) relative to the sham (9.07 ± 1.09 and 0.48 ± 0.1, respectively). Upon betanin administration, both MDA and NO approached baseline levels (9.95 ± 0.92 and 0.5 ± 0.06, respectively). Pathological examination of lumen diameter and wall thickness of the femoral arteries also revealed that betanin administration resulted in significant increase in lumen diameter when compared to vasospasm group (614.15 ± 245.77 versus 117.40 ± 46.19 µm) and decrease in wall thickness (64.68 ± 14.13 versus 96.73 ± 9.20 µm). Conclusion: Betanin was shown to have protective effect against oxidative stress in a peripheral artery vasospasm model in rats. It may also have a role in mitigating maladaptive changes in arterial structure, as shown in pathological examination.

A New Technique of Myocardial Protection during Aortic Root Replacement: Antegrade/Retrograde Coronary Perfusion

Aortic root surgery has traditionally been performed with an arrested and cooled heart using cardioplegia. A new technique of myocardial protection was utilized in the treatment of ascending aortic aneurysm with severe aortic valve regurgitation requiring aortic root replacement with the Cabrol technique. Retrograde and antegrade perfusion of the heart with blood allowed the surgical operation to be performed safely while the heart was beating and eliminated the ischemic reperfusion injury which occurs during cardioplegic arrest and reinstitution of blood perfusion after removal of the aortic cross-clamping required in traditional techniques.

Repair of postinfarction ventricular septal defect through the right atrium

Repair of post infarction posterior ventricular septal defect has generally been performed with a ventriculotomy through the infarcted zone. This approach has a significant mortality and morbidity due to haemorrhage, extension of infarction or further compromise of ventricular function secondary to suture placement. We present a case with delayed repair of a post infarction posterior septal defect using a right atrial approach, where no discrete infarct or other abnormality of the free ventricular wall was found.

Redo valve surgery with on-pump beating heart technique

AIM

Reoperations have become of increasing frequency in the last four decades. Redo surgery is more complex than primary surgery and is associated with higher mortality and morbidity. We present our immediate and mid-term results of mitral and aortic prosthetic valve replacement undertaken with beating heart technique.

METHODS

The prospective study included 26 consecutive redo valve surgery patients who underwent valve re-replacement. The operation was carried out on a beating heart using normothermic bypass without cross-clamping the aorta for mitral valve surgery and retrograde coronary sinus normothermic noncardioplegic blood perfusion during cross-clamping the aorta for aortic valve procedures.

RESULTS

Twenty-six patients (mean age 50+/-15 years) underwent reoperation with beating heart technique. Twenty (76.9%) mitral prosthetic replacements, 4 (15.4%) aortic prosthetic replacements, and 2 (7.7%) double valve replacements were achieved. Fourteen patients (53.8%) were operated for prosthetic valve dysfunction. Eighteen patients (69.2%) were in NYHA class III or IV preoperatively. Mean bypass time was 85+/-30 min. Mean duration of ventilation was 13.6+/-6 h, mean intensive unit stay was 2.8+/-6.4 days, and mean hospital stay was 8.3+/-7.2 days. Two (7.7%) patients required high dose inotropic support and in one patient (3.8%) intra-aortic balloon support was required. Pulmonary complication occurred in 1 patient (3.8%), low cardiac output in 1 patient (3.8%), and re-exploration for bleeding in 2 patients (7.7%). Operative mortality was not observed.

CONCLUSION

Normothermic on-pump beating heart valve replacement offers a safe alternative to cardioplegic arrest in high-risk group. Complication rates are low and perioperative mortality is lower than with conventional surgery. Beating heart technique has the advantage of maintaining physiologic condition of the heart throughout the procedure.

Beating heart mitral valve replacement with retrograde coronary sinus perfusion technique

AIM

The aim of this study was to assess the efficacy and applicability of on-pump beating heart mitral valve replacement with Sorin Bicarbon prosthesis using retrograde coronary sinus perfusion.

METHODS

The prospective study included 17 consecutive patients who underwent mitral valve replacement with Sorin Bicarbon prosthesis using retrograde coronary sinus perfusion. The operative variables and early outcome of this procedure are presented.

RESULTS

Retrograde coronary sinus perfusion and venting the heart from the aorta and from the pulmonary vein provided good visualization of the operative field and performance of the operations without any difficulty. Partial oxygen pressures of coronary sinus perfusion blood and the returning blood from the coronary ostia were 299.7+/-30.7 and 37.6+/-6.2 mmHg respectively. Postoperative peak creatine kinase-MB and troponin T values were 58+/-28.5 IU/L and 1.5+/-0.4 ng/mL, respectively. No mortality or major complication was observed and all the patients were discharged from the hospital in good condition.

CONCLUSIONS

On-pump beating heart mitral valve replacement with Sorin Bicarbon is a good surgical option, and it has the advantage of maintaining physiologic condition of the heart throughout the procedure.