Coronary artery surgery: conventional coronary artery bypass grafting versus off-pump coronary artery bypass grafting

Effects of Selenium Supplementation on Metabolic Status in Patients Undergoing for Coronary Artery Bypass Grafting (CABG) Surgery: a Randomized, Double-Blind, Placebo-Controlled Trial

This study was carried out to evaluate the effects of selenium supplementation on glycemic control, lipid profiles, and biomarkers of inflammation and oxidative stress in patients undergoing for coronary artery bypass grafting (CABG) surgery. This randomized, double-blind, placebo-controlled trial was performed among 33 patients undergoing for CABG surgery, aged 40-85 years old. Subjects were randomly allocated into two groups to intake either 200 μg/day selenium supplements as selenium yeast (n = 17) or placebo (n = 16) for 4 weeks. Glycemic control, lipid profiles, and biomarkers of inflammation and oxidative stress were assessed at baseline and at the end of trial. After the 4-week intervention, selenium supplementation significantly decreased fasting plasma glucose (FPG) (β, 6.76 mg/dL; 95% CI, - 13.13, - 0.40; P = 0.03), insulin (β, - 1.14 μIU/mL; 95% CI, - 2.01, - 0.28; P = 0.01); homeostasis model of assessment-estimated insulin resistance (HOMA-IR) (β - 0.35; 95% CI, - 0.62, - 0.08; P = 0.01); and total-/HDL-cholesterol ratio (β - 0.31; 95% CI, - 0.51, - 0.09; P = 0.008); and significantly increased HDL-cholesterol levels (β, 2.72 mg/dL; 95% CI, 0.89, 4.55; P = 0.005) compared with the placebo. Moreover, selenium supplementation led to a significant reduction in high-sensitivity C-reactive protein (hs-CRP) (β, - 0.68 mg/L; 95% CI, - 1.18, - 0.17; P = 0.01) and malondialdehyde (MDA) (β, - 0.27 μmol/L; 95% CI, - 0.47, - 0.07; P = 0.009), and a significant elevation in total glutathione (GSH) levels (β, 77.33 μmol/L; 95% CI, 56.11, 98.55; P < 0.001) compared with the placebo. Selenium supplementation did not affect other metabolic profiles. Overall, our study demonstrated that selenium supplementation for 4 weeks to patients undergoing for CABG surgery had beneficial effects on FPG, insulin, HOMA-IR, total-/HDL-cholesterol ratio, HDL-cholesterol, hs-CRP, GSH, and MDA levels, but did not affect other metabolic profiles. Clinical trial registration number: http://www.irct.ir : IRCT2017090533941N22.

Inhibitory Effect of TLR4 Gene Silencing on Intimal Hyperplasia of Vein Grafting

PURPOSE

The present study aimed to explore the regulating effect of Toll-like receptor 4 (TLR4) on intimal hyperplasia in rat vein grafts.

METHODS

Rat models of external jugular vein carotid artery bypass grafting were established. Afterward, TLR4 small interfering RNA (siRNA) recombinant plasmids were constructed, which were transfected into rat vein graft bypass to study the effect of TLR4 silencing on intimal hyperplasia and to explore the underlying mechanisms. Real-time polymerase chain reaction and Western blot were used to detect the expression levels of TLR4 and inflammatory factors in TLR4 siRNA-transfected vein graft bypass. The intimal thickness was evaluated using hematoxylin-eosin staining.

RESULTS

Compared with the scramble siRNA group, the intimal thickness of vein grafting was decreased significantly, while the inflammatory factors including interleukin (IL) 1β, IL-6, and tumor necrosis factor α in grafted vein were dramatically downregulated in the TLR4 siRNA group.

CONCLUSION

These results showed that local silencing of TLR4 in the vein grafts could inhibit intimal hyperplasia by downregulating the expression of inflammatory factors in the vein grafts, suggesting that TLR4 can be used as a new target for therapy of vascular intimal hyperplasia.

Off-Pump Coronary Artery Bypass Surgery in Severe Left Ventricular Dysfunction

Our aim was to examine hospital outcomes of coronary artery bypass surgery in patients with and without left ventricular dysfunction, with regard to the surgical technique (off- or on-pump). Between March 2007 and March 2008, 689 consecutive patients underwent isolated first-time coronary artery bypass; 127 had ejection fractions ≤30% (group 1) and 562 had ejection fractions >30% (group 2). Data of preoperative risk profiles and hospital outcomes were collected prospectively. Off-pump operations were performed in 49 (38.6%) patients in group 1 and 196 (34.9%) in group 2. The incidences of infectious, neurologic, and cardiac complications postoperatively were significantly higher in group 1. In multivariate analysis, preoperative ejection fraction ≤30% was found to be an independent risk factor for postoperative complications and hospital mortality. The subgroup of patients undergoing off-pump surgery in both groups had a significantly lower rate of total complications than those undergoing conventional on-pump operations, but no significant difference in mortality was observed between those undergoing off-pump or conventional surgery in either group. Off-pump surgery helped to limit the increased morbidity rate after coronary bypass in patients with ventricular dysfunction.

Heart Rate Variability after Off-Pump versus On-Pump Coronary Artery Bypass Graft Surgery

Background. It is known that after coronary artery bypass graft surgery (CABG) heart rate variability (HRV) becomes significantly decreased with a gradual recovery in a few months after surgery. However, literature data about the impact of the off-pump CABG on postoperative HRV are not complete. Therefore, the aim of this study was to analyze postoperative value of HRV in CABG patients operated on with off-pump versus on-pump coronary surgery. Methods. This study included 206 consecutive patients who underwent CABG. Sixty six patients (32%) were operated on off-pump while 140 patients (68%) were operated on using the machine for extracorporal circulation. HRV was analyzed from 24-hours Holter electrocardiogram recordings. Results. No significant differences in postoperative values of HRV variables were found between off-pump versus on-pump CABG patients (Mean RR interval 885 ± 106 versus 879 ± 125 ms, standard deviation of all normal R-R intervals 107 ± 30 versus 105 ± 34 ms, NS, total power 2298 ± 2472 versus 2156 ± 1913 ms², NS). Conclusions. The results of the study showed that there are no differences in HRV few months after surgery between patients operated on with off-pump versus on-pump CABG.

Fewer grafts performed in off-pump bypass surgery: patient selection or incomplete revascularization?

BACKGROUND

Comparisons of off-pump (OPCAB) versus conventional on-pump coronary artery bypass (CCAB) consistently report fewer grafts per patient with OPCAB. Performing fewer grafts than indicated based on angiographic assessment could result in incomplete revascularization. We questioned whether OPCAB influenced surgeons to perform fewer grafts than needed.

METHODS

Preoperative angiographic and surgical data were collected prospectively on 945 patients undergoing coronary artery bypass grafting (370 OPCAB, 575 CCAB) at 8 hospitals between February 1, 2004, and July 31, 2004. The number of grafts needed per patient was determined from the reported number of vessels with angiographic stenoses of 50% or greater, and compared with the number received per patient, stratified by coronary artery bypass grafting technique.

RESULTS

The OPCAB and CCAB groups were demographically similar. The mean number of grafts needed per patient was significantly less in the OPCAB group (2.95 versus 3.48), accounting for fewer grafts received in that group (2.75 versus 3.36). The ratio of grafts (received/needed) was the same in both groups. Patients receiving more than three grafts were more likely to have CCAB (71.2%), whereas those receiving fewer than three grafts were almost as likely to have OPCAB as CCAB (55.5%). The rate of 1-year major adverse events (death, myocardial infarction, repeat revascularization) was the same in OPCAB and CCAB (15.5% versus 14.1%; p = 0.57).

CONCLUSIONS

Completeness of revascularization, determined by comparing the number of grafts performed to the number needed, was equivalent in OPCAB and CCAB patients, and 18-month clinical outcomes were equivalent. Preferential selection of patients needing more bypass grafts to CCAB results in the lower mean number of grafts per patient with OPCAB.

Differences between early, intermediate, and late angioplasty after coronary artery bypass grafting

The aim of the present study was to identify patients with recurrent ischemia after coronary artery bypass surgery (CABG) treated by percutaneous coronary intervention (PCI). Graft failure after CABG may be managed conservatively or treated by surgery or PCI. We thought to investigate clinical, angiographic, and procedural characteristics in relation to clinical outcome. This was a retrospective single-center study. Patients who underwent revascularization by PCI with a previous CABG were analyzed. Patients were divided in 3 groups, depending on interval between CABG and index PCI: group 1, interval <72 hours; group 2, interval between 72 hours and 1 year; group 3, interval >1 year. Two hundred twenty-one patients were studied. Clinical characteristics and survival curves were comparable in groups 2 and 3. Postoperative creatine kinase MB and troponin values were significantly higher in group 1 (P = 0.000). From group 1, significantly more patients (10.5%) required emergency CABG after the index PCI than compared with group 2 (2.1%) and group 3 (0%), (P = 0.003). There were more off-pump CABGs in group 1 than in the other 2 groups. Group 1 received less PCIs in native ungrafted vessels compared with the other 2 groups. Mortality in group 1 (18.4%) was higher than in the other 2 groups (7.4 and 4.5%, respectively; P < 0.05). Mortality in group 1 was higher in the acute phase of follow-up. PCI performed less than 72 hours after CABG is feasible but accompanied by a higher mortality and redo CABG. This outcome is probably related to the high-risk patient category.

Technology insight: brain MRI and cardiac surgery--detection of postoperative brain ischemia

Annually, an estimated 1 million patients undergo heart surgery worldwide. Unfortunately, stroke continues to be a frequent complication of cardiac surgery, with the specific cerebrovascular risk depending upon the particular surgical procedure performed. Neuroimaging has an integral role in the initial evaluation and management of patients who present with acute stroke symptoms following cardiac surgery. The aim of this paper is to review the role brain MRI has in detecting postoperative brain ischemia in these patients. Multimodal MRI--using diffusion-weighted MRI (DWI), perfusion-weighted MRI, and gradient-recalled echo imaging--has an excellent capacity to identify and delineate the size and location of acute ischemic strokes as well as intracerebral hemorrhages. This differentiation is critical in making appropriate treatment decisions in the acute setting, such as determining patient eligibility for thrombolytic or hemodynamic therapies. At present, DWI offers prognostic value in patients with strokes following cardiac surgery. Additionally, DWI could be a valuable tool for evaluating stroke preventive measures as well as therapeutic interventions in patients undergoing CABG surgery.