The effects of diabetes mellitus on coronary artery bypass graft surgery

The impact of age on outcomes of coronary artery bypass grafting

OBJECTIVE

As the population ages, increasing number of older patients are undergoing adult cardiac surgery. The purpose of the study is to assess the impact of age on postoperative outcomes in patients that undergo coronary artery bypass grafting (CABG).

METHODS

Patients that are ≥70 years old who underwent CABG were selected from the Nationwide/National Inpatient Sample from 2010 to 2015 using ICD-9-CM diagnosis and procedure codes. The patients who were 70-79 years old were compared to patients aged 80-89 years old to determine if the age difference of the patients had an impact on surgical outcomes. In addition, a secondary endpoint is to compare surgical outcomes between the 2 genders of the patients 80-89 years old. The rates of postoperative complications, and mortality were compared.

RESULTS

A total of 67,568 patients were identified who were ≥ 70 years old and underwent CABG. Compared to the Septuagenarians, the Octogenarians were more likely to develop cardiac complications (OR [odds ratio] =1.20, 95% CI [confidence interval] 1.12-1.23. They were also more likely to develop renal complications (P < 0001), and respiratory complications (P < 0001). The Octogenarians were also more likely to bleed postoperatively (P < 0.0001) and have a higher mortality (P < 0001). Furthermore, the female Octogenarians had a higher mortality (OR 1.25 95% CI 1.07-1.46) compared to males in the same age group.

CONCLUSIONS

The patients who were ≥ 80-89 years old had worse postoperative outcomes. The Octogenarians who were females had a higher mortality compared to their male counterparts.

The Impact of Diabetes on Early Outcomes after Routine Bilateral Internal Thoracic Artery Grafting

BACKGROUND

Increased risk of postoperative complications limits use of bilateral internal thoracic artery (BITA) grafting in diabetic patients. The authors' experience in routine BITA grafting was reviewed to investigate the impact of diabetes on early outcomes.

METHODS

Among the 4508 consecutive patients with multivessel coronary artery disease who underwent isolated coronary bypass surgery from January 1999 throughout August 2015, skeletonised BITA grafts were used in 3228 (71.6%) patients, 972 diabetic and 2256 non-diabetic. After one-to-one propensity score (PS)-matched analysis, 819 pairs of diabetic/non-diabetic patients were compared for postoperative outcomes. The operative risk was calculated for each patient according to the European System for Cardiac Operative Risk Evaluation II (EuroSCORE II).

RESULTS

Although diabetic had higher risk profiles than non-diabetic patients both in unmatched (EuroSCORE II: 5.3±7.3% vs. 3±4.2%, p<0.0001) and PS-matched series (EuroSCORE II: 5.1±7.1% vs. 3.6±4.3%, p<0.0001), there were no differences in hospital mortality (2.2% vs. 1.8%, p=0.52 and 2.1% vs. 2.3%, p=0.74, respectively). In PS-matched pairs, the use of adrenergic agonists (p=0.03), postoperative bleeding (p=0.0055) and deep incisional sternal wound infection (p=0.0018) were more frequent in diabetic patients who had a mean of longer hospital stays (p=0.023).

CONCLUSIONS

Bilateral internal thoracic artery grafting may be routinely performed even in diabetic patients despite higher risk profiles. Increased postoperative complications prolong hospital stay but do not impact on early mortality.

Impact of diabetes on mortality and complications after coronary artery by-pass graft operation in patients with left main coronary artery disease

PURPOSE

Left main disease (LMD) is a severe form of coronary artery disease (CAD). Fifty percent of patients with LMD treated conservatively die within 3-5 years of diagnosis. The aim of the study was to assess the influence of type 2 diabetes on early and late (2-year) prognosis and the risk of complications after coronary artery by-pass graft (CABG) surgery in patients with LMD.

MATERIAL/METHODS

We enrolled 257 patients diagnosed with LMD. 169 (67%) underwent CABG, 19 (8%) percutaneous coronary intervention (PCI) without left main stem protection. 30 (12%) patients had CABG previously. Patients treated with CABG were divided into two groups - with and without diabetes. There were 43 (25.4%) patients with diabetes and 126 (74.6%) without diabetes.

RESULTS

We observed more complications with wound healing (40.5% vs. 12.8%, p<0.001) and sternal dehiscence (23.8% vs. 4.0%, p<0.001) after CABG in patients with diabetes. There were no differences in 7-day, 30-day, 3-month and 1-year mortality. 2-Year mortality was also similar in both groups (11.6% vs. 11.1%, p=0.928). Patients with diabetes were more frequently hospitalized due to other reasons than angina (39.5% vs. 20.6%, p=0.014).

CONCLUSIONS

Patients with diabetes and LMD had more often complications with wound healing and sternal dehiscence after CABG than patients without diabetes. Type 2 diabetes did not influence early and late mortality in patients with LMD treated with cardiac surgery, but the presence of diabetes was associated with more frequent hospitalizations.

A modified portfolio diet complements medical management to reduce cardiovascular risk factors in diabetic patients with coronary artery disease

BACKGROUND & AIMS

Secondary prevention can improve outcomes in high risk patients. This study investigated the magnitude of cardiovascular risk reduction associated with consumption of a modified portfolio diet in parallel with medical management.

DESIGN

30 patients with type II diabetes, 6 weeks post bypass surgery received dietary counseling on a Modified Portfolio Diet (MPD) (low fat, 8 g/1000 kcal viscous fibres, 17 g/1000 kcal soy protein and 22 g/1000 kcal almonds). Lipid profiles, endothelial function and markers of glycemic control, oxidative stress and inflammation were measured at baseline and following two and four weeks of intervention. Seven patients with no diet therapy served as time controls.

RESULTS

Consumption of the MPD resulted in a 19% relative reduction in LDL (1.9 ± 0.8 vs 1.6 ± 0.6 mmol/L, p < 0.001) with no change in HDL cholesterol. Homocysteine levels dropped significantly (10.1 ± 2.7 vs 7.9 ± 4 μmol/L, p = 0.006) over the study period. Flow mediated dilatation increased significantly in treated patients (3.8 ± 3.8% to 6.5 ± 3.6%, p = 0.004) while remaining constant in controls (p = 0.6). Endothelial progenitor cells numbers (CD34+, CD 133+ and UEA-1+) increased significantly following MPD consumption (p < 0.02) with no difference in migratory capacity. In contrast, time controls showed no significant changes.

CONCLUSION

Dietary intervention in medically managed, high risk patients resulted in important reductions in risk factors. Clinical Trials registry number NCT00462436.

A retrospective review of leg wound complications after coronary artery bypass surgery

Little research or attention has been paid to finding out whether wound closure with sutures or staples attains the best outcomes after saphenous vein harvest for coronary artery bypass grafting. We undertook a quality improvement project to compare the prevalence of leg wound complications (eg, infection, seroma, hematoma, dehiscence) between two types of skin closure (ie, staples, subcuticular sutures) after conventional open surgery with bridging between incisions and vein harvesting during coronary revascularization to determine the need for practice changes. We found no significant differences between patients with wound complications and those without. However, in this project, the risk for infections was greater for patients with diabetes whose wounds were closed by using subcuticular sutures. These findings have led to practice changes for reducing leg wound complications within our institution: clinicians now assess patients for increased risk of leg wound complications preoperatively and opt to close wounds with staples for patients who have diabetes.

Diabetes mellitus and its impact on long-term outcomes after coronary artery bypass graft surgery

Diabetes mellitus (DM) is an important risk factor for accelerated atherosclerosis and increases cardiovascular disease. Several studies found a higher mortality rate in postoperative diabetic patients than in non-diabetic patients. However, other studies found conflicting evidence on bypass graft dysfunction in patients with diabetes mellitus. We therefore investigated the influence of diabetes mellitus on the long-term outcome after coronary artery bypass surgery (CABG). In this prospective study, 936 consecutive CABG patients were included. These patients were divided into three groups: patients without diabetes mellitus, patients with diabetes mellitus using oral drugs (non-insulin-treated DM) and patients with diabetes mellitus using insulin (insulin-treated DM). The three groups were compared for mortality and (angiographic) bypass graft dysfunction. Of the 936 included patients, 720 (76.8%) patients were non-diabetics, 138 (14.7%) were non-insulin-treated DM, and 78 (8.3%) patients were insulin-treated DM. Follow-up was achieved in all patients, at a mean of 33 months. Mortality was significantly higher in patients with insulin-treated DM, compared with non-insulin-treated DM or non-diabetic patients (P = 0.003). Fourteen (1.5%) patients suffered a myocardial infarction after CABG. A coronary angiography was performed in 77 (8.2%) patients during follow-up, proven bypass graft dysfunction was found in 41 (53.2%) patients. There was no significant difference in bypass graft dysfunction between the three groups. Diabetes mellitus has a significant impact on long-term follow-up after coronary surgery. Particularly insulin dependency is related to an increased mortality. However, diabetes has no influence on angiographically proven bypass graft dysfunction.

Impact of diabetes on muscle mass, muscle strength, and exercise tolerance in patients after coronary artery bypass grafting

BACKGROUND

The impact of diabetes mellitus (DM) on muscle mass, muscle strength, and exercise tolerance in patients who had undergone coronary artery bypass grafting (CABG) has not been fully elucidated.

METHODS

We enrolled 329 consecutive patients who received cardiac rehabilitation (CR) after CABG (DM group, n=178; non-DM group, n=151) and measured lean body weight, mid-upper arm muscle area (MAMA), and handgrip power (HGP) at the beginning of CR. We also performed an isokinetic strength test of the knee extensor (Ext) and flexor (Flex) muscles and a cardiopulmonary exercise testing at the same time.

RESULTS

No significant differences in risk factors, including age, gender, number of diseased vessels, or ejection fraction were observed between the 2 groups. The levels of Ext muscle strength, peak oxygen uptake, and anaerobic threshold were significantly lower in the DM group than in the non-DM group (all p<0.05). Both peak oxygen uptake and MAMA correlated with Ext and Flex muscle strength as well as HGP (all p<0.005). The MAMA, HGP, and Ext muscle strength were lower in patients who received insulin therapy than in those who did not. Interestingly, fasting glucose levels significantly and negatively correlated with Ext muscle strength.

CONCLUSIONS

These data suggest that DM patients had a lower muscle strength and exercise tolerance than non-DM patients. Moreover, a high glucose level may affect these deteriorations in DM patients after CABG.

Differences in myocardial PTEN expression and Akt signalling in type 2 diabetic and nondiabetic patients undergoing coronary bypass surgery

OBJECTIVE

Patients with diabetes experience increased cardiovascular complications after cardiac surgery. Hyperglycaemia predicts increased mortality after myocardial infarction and may influence cardiovascular risk in humans. Impaired prosurvival phosphatase and tensin homologue on chromosome 10 (PTEN)-Akt signalling could be an important feature of the diabetic heart rendering it resistant to preconditioning. This study was designed to evaluate for differences and relationships of myocardial PTEN-Akt-related signalling and baseline glycaemic control marker in type 2 diabetic and nondiabetic patients undergoing coronary artery bypass surgery.

METHODS

Right atrial biopsies and coronary sinus blood were obtained from 18 type 2 diabetic and 18 nondiabetic patients intraoperatively. Expression and phosphorylation of Akt, endothelial nitric oxide synthase (eNOS), Bcl-2 and PTEN were evaluated by Western blot. Plasma 15-F(2t) -isoprostane concentrations were evaluated by liquid chromatography-mass spectrometry.

RESULTS

PTEN expression and 15-F(2t) -isoprostane concentrations were significantly higher in diabetic patients. Increased fasting blood glucose levels correlated with increased coronary sinus plasma 15-F(2t) -isoprostane concentrations. Increased cardiac 15-F(2t) -isoprostane generation was highly correlated with myocardial PTEN expression. Bcl-2 expression and eNOS phosphorylation were significantly lower in diabetic compared with nondiabetic patients. Akt phosphorylation tended to be lower in diabetic patients; however, this tendency failed to reach statistical significance.

CONCLUSION

The current results suggest that prosurvival PTEN-Akt signalling is impaired in the diseased diabetic myocardium. Hyperglycaemia and increased oxidative stress may contribute to this phenomenon. These findings strengthen the understanding of the underlying biologic mechanisms of cardiac injury in diabetic patients, which could facilitate development of new treatments to prevent cardiovascular complications in this high-risk population.