Martti Lepojärvi

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)

Early Neuropsychological Outcome after Carotid Endarterectomy

30 patients with a history of transient ischemic attacks (TIA) and 16 patients with cerebral infarcts were evaluated neuropsychologically 1-3 days before carotid endarterectomy, due to hemodynamically significant carotid artery stenosis, and again 2 weeks and 2 months after operation. Preoperatively, there were no differences between the groups, but postoperatively the neuropsychological outcome of the TIA patients was better than that of the infarction patients. Consequently, carotid endarterectomy patients cannot be studied as one group in neuropsychological examinations but various subgroups should be dealt with separately. In the TIA group 2 months after operation, the patients with left-sided operations had improved in verbal but not in visual tests, and the right-operated patients showed improvement also in visual tests. Therefore, the use of sum scores across neuropsychological tests is not preferable in the evaluation of the effects of carotid endarterectomy because after unilateral operation the cognitive improvement is greater in functions ipsilateral to the operation side.

Reversible ischemic inhibition of F1F0-ATPase in rat and human myocardium

The physiological role of F(1)F(0)-ATPase inhibition in ischemia may be to retard ATP depletion although views of the significance of IF(1) are at variance. We corroborate here a method for measuring the ex vivo activity of F(1)F(0)-ATPase in perfused rat heart and show that observation of ischemic F(1)F(0)-ATPase inhibition in rat heart is critically dependent on the sample preparation and assay conditions, and that the methods can be applied to assay the ischemic and reperfused human heart during coronary by-pass surgery. A 5-min period of ischemia inhibited F(1)F(0)-ATPase by 20% in both rat and human myocardium. After a 15-min reperfusion a subsequent 5-min period of ischemia doubled the inhibition in the rat heart but this potentiation was lost after 120 min of reperfusion. Experiments with isolated rat heart mitochondria showed that ATP hydrolysis is required for effective inhibition by uncoupling. The concentration of oligomycin for 50% inhibition (I(50)) for oxygen consumption was five times higher than its I(50) for F(1)F(0)-ATPase. Because of the different control strengths of F(1)F(0)-ATPase in oxidative phosphorylation and ATP hydrolysis an inhibition of the F(1)F(0)-ATPase activity in ischemia with the resultant ATP-sparing has an advantage even in an ischemia/reperfusion situation.

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.

A Retrospective Comparative Study of Aortic Valve Replacement with St. Jude Medical and Medtronic-Hall Prostheses: A 20-year Follow-up Study

Objective - To compare the long-term clinical outcome of patients who underwent aortic valve replacement with St. Jude Medical and Medtronic-Hall mechanical prostheses. Design - From June 1978 to June 1982, 43 Medtronic-Hall and 48 St. Jude Medical mechanical valves were implanted in 90 consecutive patients with aortic valve disease, and their clinical outcome was retrospectively assessed. Results - At 20 years in the St. Jude Medical group and in the Medtronic-Hall group the actuarial rates of overall survival were 50 and 49% ( p = NS), of cardiovascular survival 66 and 63% ( p = NS), of valve-related survival 95 and 91% ( p = NS), of freedom from major valve-related complications 83 and 45% ( p = 0.005), from major cerebrovascular events 93 and 71% ( p = 0.06), from valve thrombosis 97 and 89% ( p = NS), from aortic valve reoperation 93 and 88% ( p = NS), from major bleeding 96 and 82% ( p = 0.04), and from endocarditis 93 and 82% ( p = NS), respectively. The linearized rate of overall major aortic valve prosthesis-related complications was 3.47%/year in the Medtronic-Hall valve group and 1.53%/year in the St. Jude Medical valve group ( p = 0.003). Multivariate analysis showed that the type of prosthesis was predictive of freedom from valve-related complications ( p = 0.01; 2.849; C.I. 95%: 1.246-6.516). Conclusion - The aortic St. Jude Medical mechanical valve seems to be associated with a slightly lower rate of longterm valve-related morbidity than the aortic Medtronic-Hall mechanical valve. Because of the small patient population and the retrospective nature of the study, the choice between these two prostheses should not be made only on the basis of these findings. However, these results suggest a reappraisal for further comparative studies with such an extended follow-up.

Predictors of postoperative mortality after mitral valve repair: analysis of a series of 164 patients.

Background.u2005Mitral valve repair (MVR) has been shown to achieve good long-term results. However, this procedure is associated with relevant immediate postoperative mortality. The aim of this study is to identify those preoperative variables associated with an increased risk of 30-d postoperative death. Methods.u2005One hundred and sixty-four patients underwent MVR at our institution from January 1993 to December 2000. Results.u2005Eleven patients (6.7%) died during the immediate postoperative outcome, a median of 14 d after surgery (range, 1–29 d). One patient (1.3%) out of 80 who underwent MVR as lone procedure died on postoperative day 14 of cardiac tamponade. The mortality rate in those who underwent MVR associated with other procedures was 11.9%. Multivariable analysis (154 patients included in the analysis) showed that patients’ age (p=0.006, for an increase of 10 units: OR 4.33, 95% CI 1.53–12.27), history of prior cardiac surgery (p=0.006, OR 118.56, 95% CI 4.03–3491.14) and NYHA functional class (p=0.011, OR 5.66, 95% CI 1.49–21.49) were significantly associated with an increased risk of postoperative death. The receiver operating characteristics (ROC) curve showed that patients’ age had an area under the curve of 0.762 (95% CI 0.622–0.901, p=0.004), its best cut-off value being 65 years (mortality, 13.4% vs 2.1%, p=0.008, sensitivity 81.8%, specificity 62.1%, accuracy 63.4%). None of the patients older than 65 and with a history of prior cardiac surgery survived the operation. Conclusions.u2005MVR is associated with a relevant 30-d mortality risk in patients older than 65 years, with advanced NYHA functional class and a history of prior cardiac surgery.

Serum myoglobin/carbonic anhydrase III ratio in the diagnosis of perioperative myocardial infarction during coronary bypass surgery

Abstract Objective- The purpose of the present study was to evaluate the usefulness of the myoglobin/carboanhydrase III (Myo/CAIII) ratio in the diagnosis of peri operative myocardial infarction during coronary artery bypass surgery. Design- Thirty patients undergoing elective coronary artery bypass grafting (CABG) were included in the series. The patients were randomized in two groups: One received conventional normothermic retrograde blood cardioplegia, while the other was subjected to a 5-min period of ischemic preconditioning before cardioplegia. Biochemical markers for myocardial and skeletal muscle injury were measured in serial blood samples taken postoperatively from 4 h after aortic declamp. Results- Three patients were diagnosed to have suffered from peri operative myocardial infarction on the basis of significant elevations of troponin T and creatine kinase MB-isoenzyme (CK-MB) concentrations. In these particular patients the Myo/CAIII ratio Increased rapidly after aortic declamping. In uncomplicated patients, the median value of the Myo/CAIII ratio remained within normal limits. There was a Positive correlation between the net output of lactate during the aortic cross-clamping period and post-perative Myo/CAIII ratio. The Myo/CAIII ratio proved to be a more specific indicator for myocardial damage than myoglobin alone. The Myo/CAIII ratio was higher in the preconditioning group than in the Control group. Conclusion- Myo/CAIII ratio is a sensitive and specific marker for perioperative myocardial infarction Increasing rapidly after aortic declamping. This ratio could also be used when assessing the extent of ischemic myocardial injury and comparing different Surgical and cardioprotective techniques.

Predictors of Diseased Ascending Aorta in Patients Undergoing Off-Pump Coronary Artery Bypass Surgery

OBJECTIVEnTo identify the preoperative risk factors associated with increased prevalence of atherosclerotic lesions of the ascending aorta among patients undergoing off-pump coronary artery bypass surgery (OPCAB).nnnMATERIAL AND METHODSnOPCAB was performed in 241 patients who were intraoperatively investigated by epiaortic ultrasound for the presence of atherosclerotic lesions of the ascending aorta. The Northern New England Cardiovascular Disease Study Group (NNECVDSG) and the Multicenter Study of Perioperative Ischemia (McSPI) stroke risk scores were retrospectively calculated.nnnRESULTSnA diseased ascending aorta was detected by intraoperative epiaortic ultrasound in 74 patients (30.7%). Patients age (P = .002, odds ratio [OR] 1.067, 95% confidence interval [CI] 1.025-1.110), diabetes (P = .023; OR, 2.211; 95% CI, 1.117-4.378), extracardiac arteriopathy (P = .014; OR, 2.567; 95% CI, 1.214-5.428) and urgent/emergency operation (P < .0001; OR, 3.066; 95% CI, 1.685-5.580) were independent preoperative predictors of a diseased ascending aorta. The area under the ROC curve of the NNECVDSG score in predicting a diseased ascending aorta was 0.710 (95% CI, 0.642-0.778), and that of the McSPI score was 0.722 (95% CI, 0.655-0.788). The prevalence of a diseased ascending aorta was 11.2%, 34.7%, and 49.4% among the NNECVDSG score tertiles (P < .0001), and 11.3%, 31.7%, and 49.4% among the McSPI score tertiles (P < .0001).nnnCONCLUSIONSnThese findings confirm the reported high incidence of a diseased ascending aorta in patients undergoing coronary artery bypass surgery. Current stroke risk scores, particularly the simple NNECVDSG score, are valuable predictors of increased prevalence of a diseased ascending aorta.

Pulmonary artery blood temperature at admission to the intensive care unit is predictive of outcome after on‐pump coronary artery bypass surgery

Objective—To evaluate whether pulmonary artery blood (PA) temperature on admission to the intensive care unit (ICU) is predictive of postoperative outcome after isolated on‐pump coronary artery bypass grafting (CABG). Design—A retrospective study on 1639 patients who underwent isolated on‐pump CABG in whom PA temperature at admission to the ICU was available for review. Results—Thirty‐three patients (2.0%) died during the in‐hospital stay and 87 patients (5.3%) developed low cardiac output syndrome. PA temperature at admission to the ICU was significantly associated with an increased risk of overall postoperative death (pu2005=u20050.002), cardiac death (pu2005=u20050.03), and low cardiac output syndrome (pu2005<u20050.0001), and was significantly correlated with prolonged length of ICU stay (pu2005<u20050.0001) and postoperative bleeding (pu2005=u20050.001). Patients with high PA temperature had significantly more severe comorbidities, and longer aortic cross‐clamping and cardiopulmonary bypass time. The receiver operating characteristic curve showed that PA temperature at admission to the ICU in predicting postoperative death had an area under the curve of 0.660 (pu2005=u20050.002) and its best cut‐off value was 36.4°C (sensitivity: 63.6%, specificity: 65.2%). When the PA temperature at admission to the ICU was ≥36.4°C, the postoperative mortality and low cardiac output syndrome rates were 3.6 and 8.3%, whereas they were 1.1 and 3.7% when the PA temperature at admission to the ICU was <36.4°C (pu2005u2005=u2005u20050.001, pu2005<u20050.0001), respectively. Conclusion—Patients having a PA temperature ≥36.4°C at admission to the ICU after CABG seem to be at higher risk of poor postoperative outcome.

Does angiographic severity of coronary artery disease predict postoperative outcome after coronary artery bypass surgery

Objective—It is not clear whether the severity of coronary artery disease as assessed on angiography has an impact on the postoperative outcome after coronary artery bypass surgery (CABG). Design—The angiographic status of 15 coronary arteries/segments of 2233 patients who underwent isolated on‐pump CABG was graded according to the following criteria: 1u2005=u2005no stenosis; 2u2005=u2005stenosis <50%; 3u2005=u2005stenosis of 50–69%; 4u2005=u2005stenosis of 70–89%; 5u2005=u2005stenosis of 90–99%; 6u2005=u2005vessel occlusion; and 7u2005=u2005vessel is not visualized. Results—Thirty‐seven patients (1.7%) died during the in‐hospital stay and 108 (4.8%) developed postoperatively low cardiac output syndrome. Multivariate analysis showed that along with other risk factors the overall coronary angiographic score was predictive of postoperative death (pu2005=u20050.03; OR: 1.027, 95% CI: 1.003–1.052) and of low cardiac output syndrome (pu2005=u20050.04; OR: 1.172, 95% CI: 1.010–1.218). The status of the proximal segment of the left circumflex coronary artery, the diagonal arteries and the left obtuse marginal arteries was most closely associated with adverse postoperative outcome. Conclusion—The angiographic status of coronary arteries has an impact on the immediate outcome after CABG.