Diabetes mellitus as a risk factor for pulmonary complications after coronary bypass surgery.

OBJECTIVES: In the past few years there has been increasing evidence that the respiratory function of patients with diabetes is impaired in the course of their disease. The objective of this article was to investigate whether patients with diabetes are particularly at risk of pulmonary complications during the perioperative stage of coronary bypass surgery. METHODS: The data of 8555 patients who had undergone coronary bypass operations in the years between 1996 and 2004 were analyzed. Depending on their diagnosis on admission and their fasting plasma glucose levels, these patients were classified as having "no diabetes" (fasting plasma glucose level < 126 mg/dL), "undiagnosed diabetes" (glucose level > or = 126 mg/dL), "oral therapy diabetes," or "insulin-treated diabetes." The 3 diabetic groups were compared with the nondiabetic group in terms of the preoperative and postoperative characteristics. RESULTS: The reintubation rate among patients with undiagnosed diabetes (4.6%) and among those with insulin-treated diabetes (4.5%) was significantly higher than that of nondiabetic patients (1.8%; P < .01). The proportion of patients who required respiration for periods longer than 1 day was also significantly higher among patients with undiagnosed diabetes (9.9%) and those with insulin-treated diabetes (8.6%) than among the nondiabetic patients (4.8%; P < .01). The regression models show that unidentified diabetes and insulin-treated diabetes constitute independent risk factors for perioperative pulmonary complications. CONCLUSIONS: Patients with undiagnosed and insulin-treated diabetes have a higher risk of having pulmonary complications in the perioperative course of coronary bypass operations than do nondiabetic patients. These results may be explained if one considers the lung as another target organ of the diabetic disease.

Prevalence and risks of undiagnosed diabetes mellitus in patients undergoing coronary artery bypass grafting.

BACKGROUND: Numerous studies have shown that diabetes mellitus (DM) is not identified and, consequently, inadequately treated in a substantial proportion of the patients in the general population. We know very little about the extent and the consequences of undiagnosed diabetes in the risk group of patients with coronary heart diseases. The objective of this study was therefore to determine the prevalence and the risks of undiagnosed DM among patients with coronary artery bypass. METHODS AND RESULTS: The data of 7310 patients who have undergone coronary bypass operations between 1996 and 2003 were analyzed. Depending on their diagnosis on admission and their fasting plasma glucose (FPG) level, these patients were classified as known diabetics, undiagnosed diabetics (FPG > or =126 mg/dL), or as nondiabetics (FPG <126 mg/dL) and were compared in terms of their preoperative, intraoperative, and postoperative characteristics. Among the patients with coronary bypass that we examined, we found a prevalence of diagnosed diabetics of 29.6%. The prevalence of patients with undiagnosed DM (FPG > or =126 mg/dL) was 5.2%. In comparison with the other groups (non-DM versus undiagnosed DM versus known DM), the undiagnosed diabetics more frequently required resuscitation (1.7% versus 4.2% versus 1.5%; P<0.01) and reintubation (2.1% versus 5.0% versus 3.5%; P<0.01) and often showed a longer period of ventilation >1 day (5.6% versus 10.5% versus 7.4%; P<0.01). Perioperative mortality rate was highest in this group (0.9% versus 2.4% versus 1.4%; P<0.01). CONCLUSIONS: This study is the first to publish the prevalence of undiagnosed diabetes mellitus in cardiac surgery. During the perioperative and postoperative courses, these patients displayed a substantially higher morbidity and mortality rate.

Hyperkalemic blood versus crystalloid cardioplegia in longer clamping times.

The 715 patients who had crystalloid cardioplegia were compared with 5419 who had cold hyperkalemic blood cardioplegia for isolated coronary artery grafting from 1996 through 2001. Creatine kinase-MB was measured preoperatively, at 90 min, and 7 hours after the end of extracorporeal circulation. Correlation of post-bypass creatine kinase-MB release with aortic crossclamp time and other variables in the two cardioplegia groups was made using dichotomous encoding of cardioplegia in a multivariate linear regression model. Creatine kinase-MB levels 90 min after bypass were higher in patients who had crystalloid cardioplegia than in those who had blood cardioplegia. There was a linear relationship between aortic crossclamp time and post-bypass creatine kinase-MB release in both cardioplegia groups. Post-bypass creatine kinase-MB release increased with aortic crossclamp time independently of other factors and significantly more with crystalloid cardioplegia than with blood cardioplegia (the slope of the regression line was 0.230 versus 0.106). Intraaortic balloon pumping was used less frequently in the blood cardioplegia group. There was an advantage with blood cardioplegia for myocardial protection in longer aortic crossclamp times for isolated coronary bypass grafting.

Preoperative high leukocyte count: a novel risk factor for stroke after cardiac surgery.

BACKGROUND: Stroke after cardiac surgery is a devastating complication. The relationship between white blood cell count (WBC) and perioperative cerebrovascular accident (CVA) has not been investigated. An effort was made to identify how preoperative WBC may relate to CVA development during or after cardiac surgery. METHODS: Prospective data were collected from 7,483 patients who underwent coronary artery bypass grafting or valvular surgery or both. WBC was determined preoperatively and postoperatively. Differentiation of WBC was examined only preoperatively. RESULTS: There were a total of 125 CVAs (10 transient ischemic attacks [TIAs], 115 strokes). WBC was significantly higher preoperatively and directly postoperatively in patients with stroke. Qualitative changes in preoperative WBC were also found in these patients (chi2; p < 0.001). The predictive power of the stepwise logistic regression model for CVA was greater when preoperative WBC was included. The risk for perioperative CVA increased starting at preoperative WBC of 9 x 10(9)/L (p = 0.044) and progressed in higher WBC ranges. WBC had a significant impact on CVA outcome (analysis of variance, p = 0.001). CONCLUSIONS: Our studies have established the correlation between high preoperative WBC and stroke during or after cardiac surgery. Furthermore, elevated preoperative WBC was related to the clinical outcome of CVA. Preoperative measures aimed at preventing or treating conditions such as infections that may cause elevated WBC may be beneficial in the prevention of stroke during or after cardiac surgery.