Juha Nissinen

Safe time limits of aortic cross-clamping and cardiopulmonary bypass in adult cardiac surgery

Objectives: We evaluated the impact of aortic cross-clamping time (XCT) and cardiopulmonary bypass time (CPBT) on the immediate and late outcome after adult cardiac surgery and attempted to identify their safe time limits. Methods: This study includes 3280 patients who underwent adult cardiac surgery of various complexities. Myocardial protection was achieved with tepid continuous antegrade/retrograde blood cardioplegia. Results: Receiver operating characteristics (ROC) curve analysis showed that XCT (area under the curve, AUC: 0.66), CPBT (AUC: 0.73) and CPBT with unclamped aorta (AUC: 0.77) were significantly associated with 30-day postoperative mortality. XCT of increasing 30-minute intervals (Odds Ratio (OR) 1.21, 95%C.I. 1.01-1.52) and CPBT of increasing 30-minute intervals (OR 1.47, 95%C.I. 1.27-1.71) were independent predictors of 30-day mortality. The best cutoff value for XCT was 150 min (30-day death: 1.8% vs. 12.2%, adjusted OR 3.07, 95%C.I. 1.48-6.39, accuracy 91.5%) and for CPBT 240 min (30-day death: 1.9% vs. 31.5%, adjusted OR 8.78, 95%C.I. 4.64-16.61, accuracy 96.0%). These parameters were significantly associated also with postoperative morbidity, particularly with postoperative stroke. Conclusions: XCT and CPBT are predictors of immediate postoperative morbidity and mortality. In our experience, cardiac procedures with CPBT<240 min and XCT<150 min were associated with a rather low risk of immediate postoperative adverse events independently of the complexity of surgery patient’s operative risk.

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)

Postoperative delirium and health related quality of life after coronary artery bypass grafting.

Objectives. We wanted to identify determinants for postoperative delirium and its influence on health related quality of life (HRQoL) during 36-month follow-up of coronary artery bypass (CABG) patients. Design. A total of 302 patients were retrospectively analyzed. HRQoL was assessed prospectively by the15D instrument. Delirium was diagnosed clinically. Results. The incidence of delirium was 6.0%. The cumulative survival (all-cause death) in 36 months was 96.1% in patients without delirium and 77.8% in patients with delirium. Age, cerebral disease, chronic heart failure, male gender, postoperative pneumonia and low output syndrome were predictors for delirium. Delirium patients needed more resources i.e. intensive care or total duration of hospitalization and experienced no positive change in HRQoL. Moreover patients with high preoperative 15D score tended to suffer fairly severe but reversible impairment during the first 6 months after the operation. Conclusions. Preoperatively older and sicker patients with complicated postoperative course are at higher risk of developing delirium after CABG. Preoperative status and operative complications together with delirium may exert negative influence on forthcoming HRQoL, which is seen especially in patients with a relatively high preoperative level of HRQoL.

Coronary Artery Bypass Surgery in Octogenarians: Long-Term Outcome Can Be Better Than Expected

BACKGROUND We have reviewed our experience with octogenarians undergoing coronary artery bypass grafting. METHODS A consecutive series of 274 patients age 80 years or greater out of 3,474 patients who underwent isolated coronary artery bypass grafting. We have assessed the intrinsic risk aged 80 years or greater by comparing them with a propensity score-matched cohort of younger patients with similar operative risk (other than age). RESULTS Thirty-day mortality (4.7% vs 1.3%, p<0.0001), combined adverse event rates (13.1% vs 6.6%, p<0.0001), and five-year survival (76.6% vs 90.4%, p<0.0001) were significantly poorer among patients aged 80 years or greater as compared with younger patients. These figures were, however, better than estimates of a recent systematic review by McKellar and colleagues (McKellar SH, Brown ML, Frye RL, Schaff HV, Sundt TM III. Comparison of coronary revascularization procedures in octogenarians: a systematic review and meta-analysis. Nat Clin Pract Cardiovasc Med 2008;5:738-46) (30-day mortality 7.2%, and five-year survival, 68%). When octogenarians were compared with 273 propensity score-matched patients aged less than 80 years, the 30-day mortality (4.8% vs 2.6%, p=0.17) and combined adverse event rates (13.2% vs 10.6%, p=0.36) did not significantly differ. Five-year survival, despite statistical significance, was not remarkably lower than that of propensity-matched patients aged less than 80 years (77.0% vs 81.3%, p=0.009). The decrease in survival of octogenarians was evident only during the first few months after surgery, but not later on. CONCLUSIONS The results of this study suggest that immediate and five-year survival of octogenarians undergoing coronary artery bypass grafting may be even better than previously estimated. Survival of octogenarians may be suboptimal only during the first few months after surgery, whereas at five years may not differ remarkably from younger patients with otherwise similar operative risk.

Infection Prophylaxis in Pulmonary Surgery: A Randomized Prospective Study

A prospective randomized study to evaluate the efficacy of antibiotic prophylaxis against postoperative infections was carried out on 120 patients undergoing pulmonary operations. The patients were randomized into two groups of 60 patients each. One group received doxycycline (deoxytetracycline) prophylaxis for five days, and the other received cefuroxime (a second-generation cephalosporin) for one day. The groups were comparable with regard to age, sex, common risk factors, diagnosis, and operative procedures. A reduction in the infection rate was noted in the cefuroxime group (10/60) compared with the doxycycline group (19/60), but the difference was not statistically significant (p = 0.055). In major infections (empyema and pneumonia) there was no difference between the groups (4/60 in the cefuroxime group and 5/60 in the doxycycline group), but a significant (p less than 0.05) reduction was noted in minor infections (6/56 and 14/55, respectively) such as lower respiratory tract infections and prolonged fever. There were no wound infections in the two study groups. There were significantly (p less than 0.05) fewer postoperative fever reactions (axillary temperature greater than 37.5 degrees C) in the cefuroxime group (30/60) compared with the doxycycline group (44/60). Both antibiotics were effective in preventing wound infections, but cefuroxime may also be beneficial in preventing minor respiratory infections. The bactericidal effect of cefuroxime may explain this finding.

EuroSCORE predicts health-related quality of life after coronary artery bypass grafting

Three hundred and two patients were evaluated for the EuroSCORE risk and health-related quality of life (HRQoL) during three years after CABG as assessed by the 15D instrument. Both additive and logistic EuroSCORE correlated significantly with the 15D score at 6, 18 and 36 months. A clinically important increase > or =0.03 in the 15D score was achieved by 50.6% of patients at 6 months, 40.0% at 18 months and 35.9% at 36 months. The rates were similar among patients with increasing EuroSCORE at 6 and 18 months, but tended to decrease at 36 months in the highest EuroSCORE group (EuroSCORE 0-2: 46.8%; 3-5: 34.8%; and 6-14: 33.3%, respectively, P=0.13). Both additive (area under the receiver operating characteristic curve, AUC: 0.582, P=0.024) and logistic EuroSCORE (AUC: 0.575, P=0.039) were predictors of a significant increase of the 15D score. The best cut-off value of the additive EuroSCORE for prediction of a clinically important improvement of the 15D score during 3-year follow-up was 3, as 46.7% of patients with EuroSCORE 0-3 and 30.1% of patients with a score >3 (P=0.006) improved clinically. The present study showed that the EuroSCORE also predicts long-term HRQoL after CABG.

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 ≥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.

Miniaturized versus conventional cardiopulmonary bypass in high-risk patients undergoing coronary artery bypass surgery

Objective: To review our results with the use of miniaturized cardiopulmonary bypass (Mini-CPB) versus conventional cardiopulmonary bypass (C-CPB) in high-risk patients (additive EuroSCORE≥6) who have undergone coronary artery bypass graft surgery (CABG). Patients and methods: This study includes a consecutive series of 236 patients with an additive EuroSCORE≥6 who underwent CABG, employing either C-CPB or Mini-CPB. Propensity score analysis was performed. Results: The study groups had similar EuroSCOREs. Stroke rate was significantly higher among C-CPB patients (5.4% vs. 0%, p=0.026). In-hospital mortality (4.8% vs. 3.4%, p=0.75) and combined adverse end-point rate were higher in C-CPB patients (20.4% vs. 13.5%, p=0.18). Postoperative bleeding and need for transfusion were similar in the study groups, but re-sternotomy for bleeding was more frequent among C-CPB patients (4.8% vs. 1.1%, p=0.26). Seventy-four propensity matched pairs had similar immediate postoperative results: C-CPB patients had higher mortality (6.8% vs. 4.1%, p=0.72), stroke (5.4% vs. 0%, p=0.12) and combined adverse end-point rates (27.0% vs. 16.2%, p=0.11), but such differences failed to reach statistical significance. Conclusions: Mini-CPB achieved somewhat better results than C-CPB in these high-risk patients undergoing isolated CABG. This study confirmed that cerebral protection could be the main benefit associated with the use of Mini-CPB.

Efflux of adenosine and its catabolites during cold blood cardioplegia

Levels of myocardial high-energy phosphates decrease during cardioplegia for open heart operations, with a subsequent increase in the level of adenosine and its metabolites. It has been demonstrated in experimental models that the effluent concentrations of purines can be used as a measure of the average myocardial energy state. Net adenylate loss and myocardial energy state were evaluated here by determining aorta-coronary sinus differences in levels of adenosine catabolites in 17 patients during cold blood cardioplegia for elective coronary artery bypass grafting. Repeated blood samples were taken before cross-clamping of the aorta, when cardioplegic solute was infused into the aortic root and grafts after five distal anastomoses, and after declamping of the aorta. The aorta-coronary sinus differences in levels of total purines increased 4.7-, 7.5-, 7.1-, 7.8-, and 10.2-fold (from the preclamp level of 1.7 +/- 0.7 mumol/L; p < 0.001) for grafts one through five anastomosed at an average of 19, 34, 50, 63, and 76 minutes after the aortic cross-clamp, respectively. Hypoxanthine and xanthine were present in the highest concentrations. Vasodilatory adenosine concentrations of 1 to 2 mumol/L were observed in the coronary sinus while the aorta was cross-clamped. There was a linear positive correlation between the aorta-coronary sinus purine differences and corresponding cross-clamp time (r = 0.62; p < 0.001). The metabolite differences settled at a more negative level after declamping of the aorta than that prevailing before placement of the cross-clamp, suggesting continuous washout of adenosine and its catabolites during the 30-minute postclamp observation period.(ABSTRACT TRUNCATED AT 250 WORDS)

Surgery of thoracoabdominal aneurysms.

Seventeen patients with thoracoabdominal aneurysms, including 5 ruptured aneurysms, were operated upon using a left diaphragm-splitting thoracoabdominal incision and the retroperitoneal route. A temporary shunt was used in 13 patients, femorofemoral perfusion in 1 and cold perfusion cooling of the kidneys in 3 patients. The step-by-step reattachment technique into ready-made limbs or holes in the Dacron graft ensured that visceral and renal ischaemic times remained within acceptable limits. The mean renal and proximal clamping times were 44 and 77 min, respectively. One patient with a ruptured aneurysm (6%) died of diffuse bleeding. The others recovered without paraplegic, renal or other severe complications. During the follow-up period, mean 44 months and range 10-116 months, 3 patients died of lung cancer and 2 of coronary disease giving a late mortality of 29%. The remaining 11 patients are alive and well. The cumulative 2- and 5-year survival is 87% and 62% respectively. The patency rate of the grafts was 100% and that of the 30 individually revascularised arteries 80%. We recommend elective surgery for thoracoabdominal aneurysms using a temporary shunt or cold perfusion cooling of the kidneys as a protective measure against perioperative ischaemia.