Risk factors for stroke after coronary artery bypass.

To determine the prevalence of stroke after coronary artery bypass grafting and to evaluate risk factors, we reviewed the records of 1000 patients undergoing coronary bypass within a 1-year time period. Demographic and perioperative data were evaluated by chi 2 analysis. A history of diabetes, evidence of mural thrombus, positive oculopneumoplethysmography findings, increased age, aortic calcification, and postoperative arrhythmias all correlated with increased risk of permanent neurologic deficit for the patient undergoing coronary bypass. Risk factors were analyzed with stepwise logistic regression. A history of diabetes, presence of mural thrombi, and aortic calcification carried a higher probability that the patient would have a permanent neurologic deficit.     

Risk factors for late stroke after coronary artery bypass grafting

BACKGROUND: Postoperative stroke is a severe complication immediately after coronary artery bypass grafting, and it significantly deteriorates the postoperative quality of life if it occurs in the long term. It was the aim of our study to determine factors associated with the occurrence of new strokes during long-term follow-up after coronary artery bypass grafting. METHODS: From 387 of 500 patients undergoing coronary artery bypass grafting (age, 67 years [33-84 years]; 76% male) who had intraoperative epiaortic ultrasonography for assessment of ascending aortic wall thickness, a complete follow-up regarding postoperative stroke was achieved. The median follow-up time was 52 months (9-74 months). RESULTS: A stroke occurred in 26 (7%) of 387 patients, and the cumulative freedom from stroke was 99%, 95%, and 89% after 1, 3, and 5 years, respectively. A significantly lower freedom from stroke was present in patients with an age of 70 years or more (P = .007), preoperative unstable angina (P = .031), chronic obstructive pulmonary disease (P = .009), carotid artery disease (P < .001), preoperative history of neurologic events (P < .001), and a maximum ascending aortic wall thickness of 4 mm or more (P = .010). Multivariate analysis revealed preoperative history of neurologic events (P = .021) to be an independent risk factor. CONCLUSION: Patients with ascending aortic atherosclerosis, older age (> or =70 years), preoperative unstable angina, chronic obstructive pulmonary disease, and carotid artery disease are at risk for late postoperative stroke after coronary artery bypass grafting. A history of neurologic events is of special predictive importance.     

Risk factors for nosocomial pneumonia after coronary artery bypass graft operations.

We attempted to determine risk factors for nosocomial pneumonia in patients undergoing a coronary artery bypass graft operation. We reviewed the microbiology and medical records for any patient with a sputum culture who had undergone a coronary artery bypass graft operation in 1988 to identify patients with pneumonia according to a standard clinical definition. We found 19 cases of pneumonia through our initial review; complete medical records were found on 15 cases. Gram-negative bacilli predominated as the most common etiologic agent causing pneumonia in this cohort. There were no clusters noted. Mortality was 26.6%. Pneumonia occurred approximately 4 days after the operation. Thirty-six controls were randomly selected from patients undergoing coronary artery bypass graft operations in 1988. Logistic regression analysis revealed that a history of chronic obstructive lung disease, duration of more than 2 days of mechanical ventilation after operation but before diagnosis of pneumonia, and receipt of gastric acid inhibitors (antacids or H2-blockers) were independent risk factors for nosocomial pneumonia. Only the last risk factor was amenable to intervention at the time of operation.     

Risk factors of stroke and delirium after off-pump coronary artery bypass surgery

Off-pump coronary artery bypass surgery (CABG) has not abolished the risk of postoperative stroke and delirium seen for on-pump CABG. Advanced arteriosclerotic changes are common in both on-pump and off-pump CABG. We sought to analyze if advanced arteriosclerotic changes are risk factors of stroke or transient ischemic attack (TIA), and delirium after off-pump CABG. Patients undergoing off-pump CABG between 2001 and 2005 were reviewed using medical records (n=685). Potential risk factors of postoperative stroke and delirium were identified from previous studies. Further, variables retrieved from carotid artery duplex scanning as indices of advanced arteriosclerosis, were examined. The incidences of postoperative stroke/TIA and delirium after off-pump CABG were 2.6% (n=18) and 16.4% (n=112), respectively. Carotid artery stenosis >50% was a significant risk factor of stroke or TIA (P=0.02) as well as delirium (P=0.04) after off-pump CABG. A history of atrial fibrillation (AF) (P=0.037) or diabetes mellitus (P=0.041) was a risk factors of postoperative stroke or TIA. In contrast, age over 75 years (P=0.006), creatinine >1.3 mg/dl (99 μmol/l) (P=0.011), a history of hypertension (P=0.001), past history of AF (P=0.024), and smoking (P=0.048) were significant risk factors of postoperative delirium.     

Risk factors for surgical wound infection and bacteraemia following coronary artery bypass surgery

BACKGROUND: There has been no consensus from previous studies of risk factors for surgical wound infections (SWI) and postoperative bacteraemia for patients undergoing coronary artery bypass graft (CABG) surgery. METHODS: Data on 15 potential risk factors were prospectively collected on all patients undergoing CABG surgery during a 12-month period. RESULTS: Of 693 patients, 62 developed 65 SWI using the Centres for Disease Control definition: 23 were sternal wound infections and 42 were arm or leg wound infections at the site of conduit harvest. There were 19 episodes of postoperative bacteraemia. Multivariate analysis revealed that: (i) diabetes, obesity and previous cardiovascular procedure were independent predictors of SWI; and (ii) obesity was an independent risk factor for postoperative bacteraemia. CONCLUSIONS: These findings suggest that improved diabetic control and pre-operative weight reduction may result in a decrease in the incidence of SWI. But further prospective studies need to be undertaken to examine (i) whether the increased SWI risk in diabetes occurs with both insulin- and non-insulin-requiring diabetes, and whether improved peri-operative diabetes control decreases SWI; and (ii) what degree of obesity confers a risk of SWI and postoperative bacteraemia, and whether pre-operative weight reduction, if a realistic strategy in this patient group, results in a decrease in SWI.     

Risk factors for sternal wound infection and mid-term survival following coronary artery bypass surgery

Objective: To identify risk factors for sternal wound infection following coronary artery bypass surgery (CABG), and to compare early and mid-term survival outcome. Methods: Data were prospectively collected for 4228 patients who underwent CABG surgery between April 1997 and March 2001. One hundred and nine (2.6%) patients developed sternal wound infection. We used logistic regression to identify independent risk factors associated with post-operative sternal wound infection. Patient records were linked to the National Strategic Tracing Service, which records all deaths in the UK, to establish current vital status. Deaths occurring over time were described using Kaplan–Meier techniques. To control for differences in patient characteristics, we used Cox proportional hazards analysis to calculate adjusted hazard ratios (HR) and 95% confidence intervals (CI). Results: The results of the logistic regression analysis found that the independent predictors of sternal wound infection were obesity (odds ratio (OR) 2.0; P<0.001), New York Heart Association class ≥3 (OR 1.6; P=0.022), use of bilateral internal mammary arteries (OR 3.2; P<0.001), increasing number of grafts (OR 1.5; P<0.001), re-exploration for bleeding (OR 3.1; P=0.011), and increased duration of mechanical ventilation (for every 10 h (OR 1.12; P<0.001)). Three hundred and forty one (8.1%) deaths occurred during the study period with mean follow up of 3.2±1.3 years. The crude HR of mid-term mortality for sternal wound infection patients was 2.51 (95% CI 1.59–3.94, P<0.001). After adjustment for pre, intra and post-operative factors, the adjusted HR of mid-term mortality for sternal wound infection patients was 1.64 (95% CI 1.03–2.61, P=0.037). The adjusted freedom from death for sternal wound infections at 30 days, and 1, 2 and 4 years was 96.8, 93.7, 91.4 and 86.7%, respectively, compared with 98.1, 96.1, 94.7 and 91.7% for patients without sternal wound infections. Conclusions: In conclusion, we have identified risk factors for sternal wound infection, many of which are modifiable. We have also shown that there is a significant increase in mortality in patients with sternal wound infection during a 4-year follow-up period after CABG.     

Risk factors for intermediate-term survival after coronary artery bypass grafting

Background. Risk factors for short-term mortality after coronary artery bypass grafting are well established, but little is known about risk factors for intermediate-term mortality.

Methods. We analyzed the outcomes of 11,815 patients undergoing coronary artery bypass grafting in one of the 43 cardiac surgery programs of the Department of Veteran Affairs. Risk factors for intermediate- and short-term mortality were determined using Cox proportional hazards regression models. Effects of risk factors during these two periods were explicitly compared.

Results. We found important differences in mortality risk-factor sets between the intermediate- and short-term periods after coronary artery bypass grafting. The majority of predictors of intermediate-term mortality were noncardiac-related variables, whereas the majority of predictors of short-term mortality were cardiac-related variables. Impaired functional status, chronic obstructive pulmonary disease, and renal dysfunction had greater effects in the intermediate-term period. Previous heart operation, angina class III or IV, previous myocardial infarction, and preoperative use of an intraaortic balloon pump had greater effects in the short-term period.

Conclusions. The risk factors for intermediate-term mortality identified in this study can augment preoperative risk assessment and counseling of patients. Clinicians should be aware of the importance of noncardiac-related variables as predictors of mortality in the intermediate-term period after coronary artery bypass grafting.     

Tachyarrhythmias and triggering factors for atrial fibrillation after coronary artery bypass operations

BACKGROUND: We evaluated the role of supraventricular arrhythmias and assessed clinical predictors of atrial fibrillation (AF) that developed after coronary artery bypass operations. METHODS: Eighty patients, with a mean age of 65.8 years, underwent 24-hour Holter monitoring preoperatively and for 4 consecutive days postoperatively, or until clinically documented AF, for analysis of the number of premature beats and tachyarrhythmias. Atrial areas and atrial peptides were measured preoperatively and postoperatively. RESULTS: Twenty-nine of 80 (36.3%) patients had postoperative AF. Preoperatively, the maximal supraventricular premature beats per minute were higher in the AF group (p = 0.02). The body mass index and total amount of cardioplegia were lower (p = 0.02 and p = 0.006, respectively), and withdrawal of beta-blockers postoperatively more frequent (p = 0.001) in the AF group, but atrial areas and atrial peptides did not differ. CONCLUSIONS: Frequent supraventricular premature beats preoperatively may indicate a propensity for AF. A larger amount of cardioplegia during the cross-clamp period may reduce the risk of postoperative AF. Further studies are mandatory to clarify why patients with lower body mass index were more prone to AF.     

Value of echocardiography for stroke and mortality prediction following coronary artery bypass grafting

There are known clinical and laboratory predictors for stroke and death following CABG. The aim of this study was to determine if transthoracic echocardiographic findings prior to CABG have additional predictive value for occurrence of perioperative cerebrovascular accident (CVA) and death. The files of patients who underwent CABG between January 2002 and November 2004, with perioperative echocardiographic assessment were reviewed. Echocardiographic variables examined included LV size, function and hypertrophy, mitral annulus calcification (MAC) and aortic valve calcification (AVC). Patients in whom post-CABG stroke or death was documented were compared with those without these endpoints. Of the 572 patients who met the study criteria, 33 (5.8%) had a neurological event and 26 (4.5%) died, four after a major stroke. One hundred and sixty-seven patients had MAC and 228 AVC. On multivariate analysis, risk factors for stroke were previous stroke (OR=2.91 CI 1.179-7.24; P<0.005), renal failure (OR=2.48 CI 1.039-5.95; P<0.001) and older age (OR=1.60 CI 0.971-2.63; P<0.001); risk factors for death were perioperative insertion of intra-aortic balloon pump (OR=33.7 CI 11.38-100; P<0.001) and peripheral vascular disease (OR=3.89 CI 1.32-11.45; P<0.001). Medically treated dyslipidemia was protective factor. LV hypertrophy significantly predicts stroke post-CABG by univariate analysis (P=0.02). There was no significant correlation between AVC and MAC with stroke, although death was slightly increased in patients with MAC (44% vs. 29.2%, P=0.114).     

Risk factors for prolonged ICU stay in patients following coronary artery bypass grafting with a long duration of cardiopulmonary bypass

Purpose Risk factors for prolonged stay in the intensive care unit (ICU) in patients following coronary artery bypass grafting (CABG) have been reported in many previous studies. However few have focused on circulatory and respiratory status as immediate postoperative risk factors. Therefore we examined immediate postoperative risk factors for prolonged ICU stay after CABG with a long duration of cardiopulmonary bypass (CPB).Methods We studied retrospectively 100 consecutive patients undergoing elective CABG with CPB. Patients were excluded from this study if the duration of aortic cross-clamping was less than 60min. Patients were divided into three groups according to the duration of the ICU stay. Patients in group A (n = 68) were discharged from the ICU on the next morning after surgery, those in group B (n = 19) stayed for 3 days, and group C (n = 13) stayed for more than 3 days. Perioperative variables were compared among the three groups and we demonstrated risk factors for prolonged (more than 3 days) ICU stay.Results There were significant differences in duration of CPB (157 ± 34 versus 184 ± 48 minutes, P < 0.05) and aortic cross-clamping (119 ± 32 versus 141 ± 40min) between groups A and B. On the other hand, there were significant differences in age (62.8 ± 7.8 versus 67.4 ± 6.2 years), mean pulmonary artery pressure (MPAP) (17 ± 2 versus 22 ± 3mmHg), and Pa_{O 2}/FI _{O 2} (PF ratio) (409 ± 94 versus 303 ± 108mmHg) on admission to the ICU between groups A and C. There were no significant differences in intraoperative fluid balance and duration of CPB. Multiple logistic regression analysis identified age (>65 years), MPAP (>21mmHg), and PF ratio (<300mmHg) as independent risk factors for more than a 3-day ICU stay.Conclusion Advanced age, increased MPAP, and decreased PF ratio on admission to the ICU were significant risk factors for a prolonged ICU stay of more than 3 days.     

Epsilon-aminocaproic acid administration and stroke following coronary artery bypass graft surgery.

BACKGROUND: Epsilon-aminocaproic acid is routinely used to reduce bleeding during cardiac surgery. Anecdotal reports of thrombotic complications have led to speculation regarding this drug's safety. We investigated the association between epsilon-aminocaproic acid administration and postoperative stroke. METHODS: Six thousand two hundred ninety-eight patients undergoing isolated coronary artery bypass graft surgery between 1989 and 1995 were studied. Data was obtained from the Duke Cardiovascular Database as well as from an automated intraoperative anesthesia record keeper. Patients identified as having postoperative stroke were reviewed and confirmed by a board certified neurologist blinded to epsilon-aminocaproic acid administration. RESULTS: Postoperative stroke occurred in 97 patients (1.5%). Three thousand one hundred thirty-five (49.8%) patients received epsilon-aminocaproic acid. Increased age was associated with a higher incidence of postoperative stroke (p = 0.0001). In contrast, there was no significant difference (p = 0.7370) in the incidence of stroke between use of epsilon-aminocaproic acid (1.3%) and nonuse (1.7%). Multivariable logistic regression found no significant effect of epsilon-aminocaproic acid use on stroke after accounting for age, date of surgery, and history of diabetes. CONCLUSIONS: This series suggests that epsilon-aminocaproic acid administration does not increase the risk of postoperative stroke.