Rolf Ekroth

Hospital Mortality and Long-term Survival in Relation to Preoperative Function in Elderly Patients with Bronchogenic Carcinoma

During an eight-year period, 82 patients 70 years of age or older were operated on for bronchogenic carcinoma. Hospital mortality was 15.9%, and five-year survival was 32%. Results of preoperative dynamic spirometry and bicycle ergometry were predictive for post-operative six-week mortality but not for long-term survival.

Incomplete revascularization reduces survival benefit of coronary artery bypass grafting: role of off-pump surgery.

OBJECTIVE We sought to analyze the influence, if any, of incomplete revascularization and on/off-pump techniques on long-term mortality after coronary artery bypass grafting. METHODS A total of 9408 patients undergoing coronary artery bypass grafting, 8461 on pump and 947 off pump, operated on between 1995 and 2004 were included in the study. Adjusted hazard function for long-term mortality was estimated with Poisson regression analysis in a model that included variables reflecting completeness of revascularization, operative method (on/off pump), and background risk factors for death. RESULTS Mean follow-up after surgical intervention for survivors was 5.0 +/- 2.8 years (range, 0.5-10.5 years), with a total follow-up of 45,076 patient years. Leaving 1 diseased vascular segment without a bypass graft in 2- or 3-vessel disease did not increase the hazard ratio for death in comparison with complete revascularization (hazard ratio, 1.05; 95% confidence interval, 0.87-1.27; P = .60). In contrast, leaving 2 vascular segments without a bypass graft in 3-vessel disease was associated with an increased hazard ratio for death (hazard ratio, 1.82; 95% confidence interval, 1.15-2.85; P = .01). Incomplete revascularization was more common in the off-pump group (P < .001) in our study. If adjusting for incomplete revascularization, there was no significant influence of the use of on/off-pump techniques on the hazard ratio for death (hazard ratio, 1.08; 95% confidence interval, 0.82-1.40; P = .57). CONCLUSIONS Incomplete revascularization of patients with 3-vessel disease is an independent risk factor for increased long-term mortality after coronary artery bypass grafting. In contrast, the use of on- or off-pump techniques had no significant effect on survival after adjusting for incomplete revascularization.

Cerebral lactate release after circulatory arrest but not after low flow in pediatric heart operations.

Arteriovenous (jugular bulb) differences in blood lactate were followed throughout the procedure and until 18 hours postoperatively in 17 children undergoing congenital heart operations during profound hypothermia. Transcranial Doppler sonography was used to monitor changes in blood flow velocity in the middle cerebral artery. Ten children had a period of total circulatory arrest (39 +/- 6 minutes) during profound hypothermia (arrest group). Another 7 children had continuous but reduced pump flow (0.6 to 1.2 L/m2) throughout hypothermic cardiopulmonary bypass (low-flow group). The mean age was 7.3 +/- 1.3 months in the arrest group and 7.9 +/- 2.2 months in the low-flow group. The mean time on bypass was 90 +/- 10 minutes in the arrest group and 75 +/- 9 minutes in the low-flow group. The velocity of blood flow in the middle cerebral artery decreased significantly (p < 0.05) in both groups to less than 50% of the preoperative level during hypothermia and increased during and after rewarming. Differences in blood lactate level were significantly less than zero (p < 0.05) from the start of rewarming until 3 hours after the end of cardiopulmonary bypass in the arrest group, whereas differences in blood lactate level remained close to zero in the low-flow group. We conclude that circulatory arrest during profound hypothermia is followed by a period with release of lactate from the brain, indicating anaerobic cerebral metabolism and possibly disturbed cerebral aerobic metabolism. This study argues for the avoidance of circulatory arrest whenever possible.

Absent diastolic cerebral blood flow velocity after circulatory arrest but not after low flow in infants

It is controversial whether profound hypothermia (15 degrees C) provides adequate cerebral protection during a limited period of total circulatory arrest during pediatric cardiac surgery. In the present study, transcranial Doppler echography was used to monitor the blood flow velocity (BFV) pattern in the middle cerebral artery (MCA). The purpose of the study was to investigate the influence of a period of circulatory arrest on MCA BFV, as judged from the reperfusion flow velocity pattern. The MCA BFV was studied in 22 small children undergoing profound hypothermic cardiac operations after induction of anesthesia. Twelve of the children had a period of profound hypothermic circulatory arrest (15 to 74 minutes; arrest group). Circulation was maintained in the remaining 10 children (nonarrest group). Time-averaged MCA BFV was decreased and diastolic BFV was absent immediately after cardiopulmonary bypass in 10 of 12 children in the arrest group. In contrast, only 1 of 10 patients in the nonarrest group (p < 0.05) showed this pattern. Diastolic BFV normalized 54 to 328 minutes after the arrest in the arrest group. Circulatory arrest during profound hypothermia is followed by a period of low cerebral perfusion, whereby time-averaged MCA BFV is decreased and MCA BFV is absent during diastole. We speculate that this can be explained by an increase in intracranial pressure after brain edema.

α-ketoglutarate for myocardial protection in heart surgery

Abstract A low myocardial content of α-ketoglutarate during heart surgery might aggravate ischaemic injury. 24 men undergoing coronary surgery participated in a randomised controlled study. 28 g α-ketoglutarate was added to blood cardioplegia for intermittent antegrade intracoronary perfusion in 13 cases. α-ketoglutarate reduced the appearance in blood of the ischaemic markers creatine kinase MB and troponin T (at 4 h after release of aortic cross-clamp; median [95% Cl] 49 [37-60] μg/L in controls vs 32 [27-37] μg/L for creatine kinase MB, 2·0 [1·2-2·8] vs 1·1 [0·8-1·4] μg/L for troponin T). These findings signify attenuated ischaemic injury, possibly secondary to enhanced myocardial oxidative capacity.

Influence of two different perfusion systems on inflammatory response in pediatric heart surgery

BACKGROUND This study tests the hypothesis that a cardiopulmonary bypass system that combines complete heparin-coating, a centrifugal pump, and a closed circuit in comparison with a conventional system (uncoated system, roller pump, and hard shell venous reservoir) attenuates the inflammatory response in pediatric heart surgery. METHODS In a prospective randomized controlled clinical study 40 consecutive children weighing 10 kg or less were included and divided into two groups. Concentrations of complement proteins (C3a, sC5b-9, C4d, and Bb), granulocyte degranulation products (polymorphonuclear [PMN] elastase), and proinflammatory cytokines (tumor necrosis factor [TNF]-alpha, interleukin [IL]-6, and IL-8) were measured. RESULTS C3a and sC5b-9 concentrations were lower (C3a, p < 0.001; sC5b-9, p = 0.01) in the combined (heparin-coated/centrifugal pump/closed reservoir) group, the peak values being 58% and 37% of conventional group values. The Bb- and C4d-fragment values indicated activation of the complement system through the alternative pathway in both groups. PMN elastase concentrations were lower (p = 0.02) in the combined group, the peak values being 43% of conventional group values. There were no significant intergroup differences regarding TNF-alpha, IL-6, or IL-8 concentrations. CONCLUSIONS The use of a fully heparin-coated system, a centrifugal pump, and a closed circuit during CPB in children (10 kg or less) leads to a lower degree of complement activation and PMN elastase release compared with a conventional system.

Thermographic Demonstration of Uneven Myocardial Cooling in Patients with Coronary Lesions

Low temperature is an important factor in protecting the myocardium during an operation on the heart. This can be difficult to accomplish if the cold cardioplegic solution is hindered by occlusions or stenosis of the coronary arteries. We used thermography to study myocardial temperature during infusion of cold cardioplegic solution. Slow cooling was recorded distal to coronary stenosis or occlusions, thereby indicating insufficient protection of the myocarium in these areas.

Addition of α-Ketoglutarate to Blood Cardioplegia Improves Cardioprotection

Abstract Background . We hypothesized that myocardial content of α-ketoglutarate (α-KG), an intermediate of the Krebs cycle, can be critically low during heart operations, and that provision of α-KG could reduce metabolic abnormalities and lead to improved myocardial protection. Methods . Twenty-four men aged 46 to 78 years who were undergoing heart operations participated in a prospective, controlled, randomized study. In 13 patients, an average of 28 g of α-KG was added to blood cardioplegia. Plasma creatine kinase isoenzyme MB and troponin T, and myocardial extraction of oxygen, substrates, and amino acids were measured. Results . α-Ketoglutarate treatment was associated with lower creatine kinase isoenzyme MB (F = 39.6, df=1.172, p p p p = 0.016). There were no other differences after 30 minutes of reperfusion. Conclusion . Provision of α-KG during blood cardioplegia improves myocardial protection in patients undergoing coronary operations. This may be linked to enhanced oxidation. (Ann Thorac Surg 1997;63:1625–34)

Insulin(GIK) improves myocardial metabolism in patients during blood cardioplegia.

The aim of this study was to test the hypothesis that abnormalities of myocardial substrate metabolism during blood cardioplegic aortic cross-clamping and early reperfusion are attenuated further by insulin(GIK) than by alpha-ketoglutarate enrichment of blood cardioplegia alone. Twenty-eight males (47 to 78 years) undergoing coronary artery bypass grafting (CABG) participated in a prospective, controlled, randomized study. All patients had alpha-ketoglutarate-enriched blood cardioplegia. Insulin(GIK) was infused in 13 patients during aortic cross-clamping. Insulin(GIK) prevented lactate release during cardioplegia (1.5+/-15 vs -44+/-14 micromol/min, p = 0.04), and a significant extraction of lactate was induced shortly after declamping the aorta (15+/-3 vs 2+/-1%, p = 0.001). Free fatty acid uptake was reduced after cardioplegic cross-clamping (5.7+/-1.6 vs 16.0+/-3.8 micromol/min, p = 0.02). More positive/less negative levels of alanine, aspartate, glutamine, glycine, ornithine, taurine and tyrosine were found in all the insulin-treated patients. We conclude that insulin(GIK) attenuates abnormalities of myocardial substrate metabolism during blood cardioplegic aortic cross-clamping and early reperfusion further than is obtained with alpha-ketoglutarate enrichment of blood cardioplegia alone.

Clinical variables and pro-inflammatory activation in paediatric heart surgery

Objectives - The first aim was to analyse the role of preoperative characteristics and perioperative variables in predicting the inflammatory response during and early after operations for congenital heart malformations of moderate to severe complexity. The second aim was to correlate complement and cytokine activation during the same period with clinical variables reflecting the postoperative course. Methods - Prospective descriptive clinical study that involved 22 consecutive children (1-28 months). Five children had Downs syndrome. Concentrations of C3a, C5b-9 and IL-6 were measured. Results - C3a, C5b-9 and IL-6 increased significantly during the study period (ANOVA: C3a, p = 0.001; C5b-9, p = 0; IL-6, p = 0). C3a correlated with preoperative haemoglobin (r = 0.71, p = 0.0002) and CPB time (r = 0.72, p = 0.0005). C5b-9 correlated with CPB time (r = 0.58, p = 0.004). IL-6 related to presence of Downs syndrome (p = 0.0001) and correlated with preoperative haemoglobin (r = 0.55, p = 0.02), preoperative weight deviation (r = -0.52, p = 0.03) and time in the ventilator (r = 0.68, p = 0.002) Conclusions - Preoperative and perioperative characteristics predict the inflammatory response during open heart surgery in infants and small children. IL-6 response is related to the postoperative course.OBJECTIVES The first aim was to analyse the role of preoperative characteristics and perioperative variables in predicting the inflammatory response during and early after operations for congenital heart malformations of moderate to severe complexity. The second aim was to correlate complement and cytokine activation during the same period with clinical variables reflecting the postoperative course. METHODS Prospective descriptive clinical study that involved 22 consecutive children (1-28 months). Five children had Downs syndrome. Concentrations of C3a, C5b-9 and IL-6 were measured. RESULTS C3a, C5b-9 and IL-6 increased significantly during the study period (ANOVA: C3a, p = 0.001; C5b-9, p = 0; IL-6, p = 0). C3a correlated with preoperative haemoglobin (r = 0.71, p = 0.0002) and CPB time (r = 0.72, p=0.0005). C5b-9 correlated with CPB time (r= 0.58, p=0.004). IL-6 related to presence of Downs syndrome (p=0.0001) and correlated with preoperative haemoglobin (r=0.55, p=0.02), preoperative weight deviation (r = -0.52, p = 0.03) and time in the ventilator (r = 0.68, p = 0.002). CONCLUSIONS Preoperative and perioperative characteristics predict the inflammatory response during open heart surgery in infants and small children. IL-6 response is related to the postoperative course.