Pulmonary function and immediate and late outcome after coronary artery bypass surgery.

AIM: The aim of this study was to evaluate whether pulmonary function as assessed by spirometry affects the immediate and late outcome after isolated coronary artery bypass surgery (CABG). METHODS: Data on preoperative percentages of the predicted forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were retrieved from a series of 1848 patients who underwent isolated CABG. Pulmonary disease was defined according to EuroSCORE criteria. RESULTS: Logistic regression showed that percentage of predicted FVC was an independent predictor of in-hospital mortality along with estimated glomerular filtration rate, age and extracardiac arteriopathy. Cox regression analysis showed that pulmonary disease and percentages of predicted FVC were independent predictors of late overall mortality. Percentage of predicted FVC < 70% (at 10-year: 63.8% vs. 74.3%, Cox regression analysis: P = 0.014, RR 1.50, 95%C.I. 1.08-2.08) and pulmonary disease (at 10-year: 58.0% vs. 76%, Cox regression analysis: P < 0.0001, RR 1.75, 95%C.I. 1.29-2.39), but not percentage of predicted FEV1 < 70%, were associated with a marked decrease in late survival. CONCLUSION: This study confirmed the significant, negative prognostic impact of pulmonary disease on the immediate and long-term survival after isolated CABG.

Peripheral vascular disease as predictor of outcome after coronary artery bypass grafting.

BACKGROUND AND AIMS: Understanding and objective assessment of risks is crucial in cardiac surgery. The aim of this study was to assess the influence of peripheral vascular disease (PVD) on morbidity, mortality and outcome in coronary artery bypass grafting (CABG) patients. MATERIAL AND METHODS: The ankle-brachial pressure index (ABPI) was used as indicator of PVD and was measured in 178 CABG patients. Two groups were established: 1. normal ABPI (0.9-1.3) (n = 136) and 2. lowered ABPI (< 0.9) (n = 35). The mean follow-up was 26 months. RESULTS: The presence of PVD was 20.5 %. Patients with PVD were older (p < 0.05), more often of female sex (p < 0.05), had higher Higgins's risk score (p = 0.001) and more often intermittent claudication (IC) (p < 0.001). PVD significantly predicted atrial fibrillation (FA) (p < 0.05) and relatively postoperative myocardial infarction (MI) (p = 0.058). CONCLUSIONS: The presence of PVD is relatively high in CABG patients and increases with age. PVD predicts some morbidity but seems to have fairly little influence on short-term or middle-term outcome of CABG patients. ABPI may be of only limited value in identifying patients with high operative risk in CABG.

Perioperative stroke in coronary artery bypass patients.

BACKGROUND AND AIMS: Stroke has remained one of the most frustrating complications in coronary artery bypass surgery (CABG). The purpose of this study was to describe the incidence and correlates of stroke in CABG patients operated on in a hospital with low annual volume of open-heart surgery procedures. The aim was moreover to clarify subsequent outcome and self-reported satisfaction-based quality of life of patients who had experienced a stroke. MATERIAL AND METHODS: The material was a cohort of 1318 consecutive CABG patients operated on over a 6-year period. Data was collected prospectively but the final analysis was retrospective. Questionnaires supplemented the estimation of survival and subsequent functional status. RESULTS: The incidence of stroke was 2.6 %. Age > 70 years, chronic obstructive pulmonary disease (COPD), peripheral vascular disease (PVD), cerebral vascular disease (CVD), number of aortic anastomoses and significant atherosclerosis of the ascending aorta were univariate predictors of stroke. Postoperative stroke was experienced in 55.9% of cases delayed appearing from 2nd postoperative day on. Stroke patients had a higher rate of mortality (14.7% vs. 1.0%, p = 0.001) and poorer survival than no-stroke patients (82.4% and 97.4% at one year and 61.2% and 89.7% at six years, p < 0.001). CONCLUSIONS: The incidence of stroke seems to be on the same level in CABG patients from a low volume hospital as in reports from centres with a high volume of annual procedures. Stroke predicts higher mortality, longer intensive care unit (ICU) stay, longer hospitalisation and poorer survival. A relatively high number of stroke patients need permanent institutional care. Satisfaction-based quality of life in CABG patients also remains on a lower level in comparison to patients without neurological complications.

Outcome after coronary artery bypass surgery with miniaturized versus conventional cardiopulmonary bypass.

We have reviewed the results of our experience with the use of miniaturized (Mini-CPB) versus conventional (C-CPB) cardiopulmonary bypass in coronary artery bypass surgery (CABG). This study included 365 patients who underwent CABG with C-CPB and 101 patients with Mini-CPB. In-hospital mortality was lower in the C-CPB group (1.4% vs. 3.0%, P = 0.38). A better, but not statistically significant, immediate outcome was observed in the C-CPB group as indicated by a shorter length of stay in the intensive care unit as well as a lower incidence of combined adverse end-point. However, this was probably due to significantly higher operative risk in the Mini-CPB group (logistic EuroSCORE: 8.5 +/- 10.0 vs. 4.6 +/- 7.1, P < 0.0001). Seventy-seven propensity score-matched pairs had similar immediate postoperative results after Mini-CPB and C-CPB (30-day mortality: 1.3% vs. 1.3%; stroke: 0% vs. 0%; intensive care unit stay > or = 5 days: 6.5% vs. 9.1%; combined adverse events: 14.3% vs. 11.7%). Mini-CPB achieves similar results to C-CPB in patients undergoing isolated CABG. The potential efficacy of Mini-CPB is expected to be more evident in high-risk patients or in complex cardiac surgery requiring much longer cardiopulmonary perfusion.

Prebypass glucose-insulin-potassium infusion in elective nondiabetic coronary artery surgery patients.

Perioperative GIK therapy has been advocated to ensure adequate energy substrate levels during cardiac surgery. However, hyperglycemia should be avoided because it may worsen neurologic outcome after cerebral ischemia. A prospective, randomized, clinical comparison was performed between two prebypass infusion regimens in 32 elective nondiabetic CABG patients. Sixteen patients (GIK group) received glucose, 0.6 g/kg/h, insulin, 0.12 U/kg/h, and KCl, 0.12 mmol/kg/h, from the induction of anesthesia to the start of CPB; while the remaining 16 patients (R group) received only Ringer's acetate. The pump prime was glucose free and a blood cardioplegia technique was used in both groups. No differences were found between the groups with regard to myocardial injury; the CK-MB enzyme fractions were elevated to a similar degree and the frequency of postoperative ECG changes were similar in both groups. Likewise, there were no differences in hemodynamic changes, need for inotropic support, arrhythmia frequency, or duration of ICU stay. The GIK patients had higher blood glucose (P < 0.05) and insulin levels (P < 0.01); blood glucose increased to 12.4 +/- 5.4 mmol/L (mean +/- SD) at cannulation, with a drop after starting bypass. Interindividual variation in GIK patients was great, with glucose values ranging between 20.1 mmol/L at cannulation to 2.0 mmol/L after starting CPB. A hyperglycemic response was seen in both groups during rewarming: 15.0 +/- 4.2 and 15.0 +/- 3.1 mmol/L in GIK and R patients, respectively. It is concluded that prebypass GIK infusion had no clinical benefits for elective CABG patients as compared to Ringer's acetate.(ABSTRACT TRUNCATED AT 250 WORDS)

Perioperative glucose-insulin-potassium infusion in elective coronary surgery: minor benefit in connection with blood cardioplegia?

OBJECTIVE: The goal of this study was to examine the metabolic and hemodynamic effects of a glucose-insulin-potassium infusion in elective coronary surgery, when blood cardioplegia was used for cardiac protection. DESIGN AND PATIENTS: A prospective, randomized, open, clinical comparison was performed between 2 perioperative infusion regimens in 40 elective nondiabetic coronary artery bypass graft (CABG) surgery patients. SETTING AND INTERVENTIONS: 20 patients (glucose-insulin-potassium-GIK-group) received glucose 0.2 g/kg/h, insulin 0.12 U/kg/h, potassium 0.15, magnesium 0.032 and phosphate 0.024 mmol/kg/h from anesthesia induction to the start of bypass, when infusion rate was reduced to 30%, and after bypass increased to 50% of the initial rate. The infusion was continued until the first postoperative morning. Another 20 patients (control-R-group) received glucose 0.05 g/kg/h, potassium 0.075, magnesium 0.016 and phosphate 0.008 mmol/kg/h from the end of bypass to the next morning. Pump prime was glucose-free and a blood cardioplegia technique was used for cardiac protection. RESULTS: The GIK patients needed less dopamine support in the intensive care unit (ICU) (p < 0.05). No difference was found between the groups with regard to myocardial injury, the MB-fractions of serum creatine kinase (CK-MB) being elevated to a similar degree in both groups. Likewise there were no significant differences in hemodynamic changes or duration of ICU stay. Although the glucose infusion was continued during bypass in the GIK patients, there was a considerable risk of hypoglycemia (due to insulin and hemodilution) after the onset of bypass: in 5 GIK patients (25%; 95% confidence interval 8.7 to 49.1%) blood glucose was less than 2 mmol/l. However, the hypoglycemia was of short duration and no detrimental effects were seen. CONCLUSIONS: Perioperative GIK infusion entailed a slight decrease in the postoperative need for dopamine support, but was connected with a considerable risk of hypoglycemia.

Amino acid-enriched glucose-insulin-potassium infusion improves hemodynamic function after coronary bypass surgery. A double-blind study in patients with unstable angina and/or compromised left ventricular function.

OBJECTIVE: The goal of this study was to assess the effects of a combination of glucose-insulin-potassium (GIK) and the amino acids aspartate and glutamate upon perioperative hemodynamics in coronary surgery patients with unstable angina and/or compromised left ventricular function. DESIGN: Prospective, randomized, and double-blind clinical study. SETTING: Operating theatre and intensive care unit (ICU) of a university hospital. PATIENTS: 44 coronary artery bypass graft (CABG) patients with unstable angina and/or compromised left ventricular function. INTERVENTIONS: 22 patients (group A) were given 1l of an infusion with 250g glucose, 100 I.U. fast-acting human insulin, 72 mmol potassium, 32 mmol magnesium, 20 mmol phosphate, 65 mmol aspartate, and 65 mmol glutamate, while another 22 patients (group C) were given 1l of an infusion with 50 g glucose, 72 mmol potassium, 32 mmol magnesium, and 8 mmol phosphate. The infusion rate was 1.2 ml/kg/h from the anesthesia induction onward to the commencement of cardiopulmonary bypass, when it was reduced to 0.8 ml/kg/h. When 11 had been infused, but not later than 4 a.m., the infusion was continued by giving 10% glucose at the same rate to both groups. Additional insulin (median: 14.2 I.U., range: 0-41.5) or saline was given during bypass to the A and C patients, respectively. A blood cardioplegia technique containing aspartate and glutamate was used in both groups. RESULTS: At aortic cannulation, the cardiac index (CI) had increased from the pre-anesthetic level by 15.3% (mean) (SD: 31.7%) in group A and decreased by 7.7% (15.1%) in C patients, p = 0.0069. Also the changes in stroke index (SI; p = 0.022), left (LVSWI; p = 0.0037) and right ventricular stroke work index (RVSWI; p = 0.0097) were more favorable in group A. Despite longer aortic cross-clamp, p = 0.031, and perfusion times, p = 0.042, in A patients, the change in cardiac index was also better in this group after bypass: At decannulation, the difference between mean values was 31.8%, p = 0.0001, and at arrival in the ICU it was 16.1%, p = 0.028. The same was also seen 8 h postoperatively and on the 1st and 2nd postoperative mornings; p = 0.034, 0.040, and 0.037, respectively (Wilcoxon test). Favorable changes were seen for the A patients also regarding SI at decannulation (p = 0.0002) and after 8 h (p = 0.017); LVSWI at decannulation (p = 0.0002), at arrival in the ICU (p = 0.0023), and after 8 h (p = 0.0011); and RVSWI at decannulation (p = 0.0027), at the ICU (p = 0.021), after 8 h (p = 0.014), and on the 1st postoperative morning (p = 0.039). However, the response to a hemodynamic loading test (6% hydroxyethyl starch 5 ml/kg) was similar in the 2 groups, and there was no difference in the need for inotropic support. CONCLUSIONS: Amino acid-enriched GIK infusion improves hemodynamic function in CABG patients with unstable angina and/or compromised left ventricular function.

Magnesium substitution in elective coronary artery surgery: a double-blind clinical study.

Magnesium may be beneficial in the control of ventricular ectopy and supraventricular tachyarrhythmias after coronary artery bypass graft (CABG) surgery, but it is not known whether a high-dose magnesium regimen is superior to a regimen keeping the patient normomagnesemic. A prospective randomized and double-blind clinical comparison was performed in 81 elective CABG patients in order to assess the effects of two different magnesium infusion regimens on electrolyte balance and postoperative arrhythmias. Forty-one patients (high-dose group, H) received 4.2 +/- 0.7 g (mean +/- SD), of magnesium sulfate before cardiopulmonary bypass, followed by an infusion of 11.9 +/- 2.8 g of magnesium chloride until the first postoperative (PO) morning, and a further 5.5 +/- 1.0 g until the second PO morning. Forty patients (low-dose group, L) received magnesium sulfate only after bypass to a total of 2.9 +/- 0.5 g at the first, and 1.4 +/- 0.1 g at the second PO morning. A blood cardioplegia technique was used in both groups, including bolus doses of magnesium chloride to a total of 2.4 +/- 0.6 g and 2.3 +/- 0.6 g to H and L patients, respectively. Continuous Holter tape-recording was used for 12 to 15 hours preoperatively, and for 48 hours postoperatively. Serum magnesium peaked in H patients on the first PO morning at 1.60 +/- 0.25 mmol/L, whereafter it declined to the normal level on the third PO morning. Patients in the L group were normomagnesemic, except after the start of bypass.(ABSTRACT TRUNCATED AT 250 WORDS)