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Background: In the recent ALBICS (ALBumin In Cardiac Surgery) trial, 4% albumin used for cardiopulmonary bypass priming and volume replacement increased perioperative bleeding compared with Ringer acetate. In the present exploratory study, albumin-related bleeding was further characterized., Methods: Ringer acetate and 4% albumin were compared in a randomized, double-blinded fashion in 1386 on-pump adult cardiac surgery patients. The study end points for bleeding were the Universal Definition of Perioperative Bleeding (UDPB) class and its components., Results: The UDPB bleeding grades were higher in the albumin group than the Ringer group: "insignificant" (albumin vs Ringer: 47.5% vs 62.9%), "mild" (12.7% vs 8.9%), "moderate" (28.7% vs 24.4%), "severe" (10.2% vs 3.2%), and "massive" (0.9% vs. 0.6%; P < .001). Patients in the albumin group received red blood cells (45.2% vs 31.5%; odds ratio [OR], 1.80; 95% CI, 1.44-2.24; P < .001), platelets (33.3% vs 21.8%; OR, 1.79; 95% CI, 1.41-2.28; P < .001), and fibrinogen (5.6% vs 2.6%; OR, 2.24; 95% CI, 1.27-3.95; P < .05), and underwent resternotomy (5.3% vs 1.9%; OR, 2.95; 95% CI, 1.55-5.60, P < .001) more often than patients in the Ringer group. The strongest predictors of bleeding were albumin group allocation (OR, 2.18; 95% CI, 1.74-2.74) and complex (OR, 2.61; 95% CI, 2.02-3.37) and urgent surgery (OR, 1.63; 95% CI, 1.26-2.13). In interaction analysis, the effect of albumin on the risk of bleeding was stronger in patients on preoperative acetylsalicylic acid., Conclusions: Perioperative administration of albumin, compared with Ringer's acetate, resulted in increased blood loss and higher UDBP class. The magnitude of this effect was similar to the complexity and urgency of the surgery., (Copyright © 2023 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Coronary artery bypass grafting (CABG) without cardiopulmonary bypass and minimal or no aortic manipulation may be associated with a lower risk of neurological complications. We investigated this issue in patients with a high risk of perioperative stroke., Methods: Data on 7352 patients who underwent isolated CABG from January 2015 to May 2017 were included in the multicenter study E-CABG (European Coronary Artery Bypass Grafting) registry. Of these, 684 patients had an increased risk of neurological complications, ie, previous stroke or transient ischemic attack, severe carotid artery stenosis or occlusion, or previous carotid artery intervention. In this subgroup, we analyzed the rates of the combined primary endpoint comprising any postoperative stroke or transient ischemic attack. A comparative analysis between CABG with and without aortic cross-clamping was performed., Results: The primary endpoint was more often reached when aortic cross-clamping was used (propensity score matching, without vs with aortic cross-clamp: 0.9% vs 7.2%; P = .016). In comparison with all other revascularization techniques, off-pump CABG with avoidance of aortic manipulation was associated with the lowest rate of neurological complications (0.7%)., Conclusions: In patients with increased risk of perioperative stroke, aortic manipulation including the use of cardiopulmonary bypass or partial clamping for central anastomoses is associated with higher rates of postoperative neurological complications. These patients may benefit from off-pump surgery without aortic manipulation if complete revascularization can be ensured., (Copyright © 2022 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: The impact of patient-prosthesis mismatch (PPM) on long-term outcome after surgical aortic valve replacement (SAVR) is controversial. We sought to investigate the incidence of PPM and its impact on survival and reinterventions in a Finnish nationwide cohort., Methods: In the context of the nationwide FinnValve registry, we identified 4097 patients who underwent SAVR with a stented bioprosthesis with or without myocardial revascularization. The indexed effective orifice areas (EOAs) of surgical bioprostheses were calculated using literature-derived EOAs. PPM was graded as moderate (EOA 0.65-0.85 cm 2 /m 2 ) or severe (EOA ≤0.65 cm 2 /m 2 )., Results: The incidence of PPM was 46.0%. PPM was moderate in 38.8% (n = 1579) patients and severe in 7.2% (n = 297) patients. Time-trend analysis showed that the proportion of PPM decreased significantly from 74% in 2009 to 18% in 2017 (P < .01). Severe PPM was associated with increased 5-year all-cause mortality (adjusted hazard ratio [HR], 1.72; 95% confidence interval [CI], 1.07-2.76; P = .02). Severe PPM was not associated with an increased risk of repeat AVR (adjusted HR, 5.90; 95% CI, 0.95-36.5; P = .06). In a subanalysis of patients greater than or equal to 70 years of age, in comparison with no PPM, any PPM (adjusted HR, 1.23; 95% CI, 1.05-1.45; P = .01) and severe PPM (HR, 1.53; 95% CI, 1.17-2.00; P < 0.01) were associated with increased risk of 5-year mortality., Conclusions: Severe PPM after SAVR had a negative impact on survival. This study demonstrated that the effects of PPM should not be overlooked in elderly undergoing SAVR., (Copyright © 2021 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: It is controversial whether peripheral arterial cannulation may achieve better results than direct aortic cannulation during surgery for Stanford type A aortic dissection., Methods: From January 2005 to December 2017, 309 consecutive patients underwent surgical repair for acute type A aortic dissection at Helsinki University Hospital, Finland. The early outcomes of patients who underwent surgery with direct aortic cannulation were compared with those of patients in whom peripheral arterial cannulation was used., Results: Direct aortic cannulation was used in 80 patients and peripheral arterial cannulation in 229 patients. Patients who underwent surgery with direct aortic cannulation had hospital mortality (13.8% vs 13.5%, P = .962) and stroke/global brain ischemia (22.3% vs 25%, P = .617) similar to that of patients who had peripheral arterial cannulation. The other secondary outcomes were equally distributed between the unmatched study cohorts. Among 74 propensity score matched pairs, direct aortic cannulation had hospital mortality rates (12.2% vs 9.5%, P = .804) and stroke/global brain ischemia rates (21.6% vs 21.6%, P = 1.000) comparable to those for peripheral arterial cannulation. The composite outcome of hospital mortality/stroke/global brain ischemia (29.7% vs 27%, P = .855), multiple stroke (16.2% vs 17.6%, P = 1.000), renal replacement therapy (11.8% vs 13%, P = 1.000) and length of stay in the intensive care unit (mean, 4.9 ± 4.5 vs 4.8 ± 4.9 days, P = .943) were also equally distributed between these matched cohorts., Conclusions: In this institutional series, central arterial cannulation allowed a straightforward surgical repair of type A aortic dissection and achieved early outcomes similar to those of peripheral arterial cannulation., (Copyright © 2020 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Recent surgical bovine pericardial prostheses are widely used despite limited data on their long-term durability., Methods: This is a comparative analysis of the outcome of the Trifecta (Abbott, Abbott Park, IL) and Perimount Magna Ease (Edwards, Lifesciences Corp, Irvine, CA) bioprostheses from the FinnValve registry, a Finnish nationwide database including patients with aortic stenosis who underwent transcatheter or surgical aortic valve replacement with a bioprosthesis between 2008 and 2017., Results: Overall 2216 patients (mean age, 74.1 ± 6.7 years; age <65 years, 8.9%; mean follow-up, 3.8 ± 2.1 years) received the Trifecta (851 patients) or the Perimount Magna Ease (1365 patients) bioprostheses. The rates of late mortality and prosthetic valve endocarditis were comparable in the study cohorts. At 7 years the Trifecta cohort had a significantly higher risk of repeat aortic valve replacement for structural valve failure (3.3% vs 0%; adjusted subdistribution hazard ratio, 2.224; 95% confidence interval, 1.044-4.737), repeat aortic valve replacement for any cause (3.6% vs 0.4%; adjusted subdistribution hazard ratio, 3.210; 95% confidence interval, 1.286-8.013), and repeat aortic valve replacement and/or prosthetic valve endocarditis (4.1% vs 0.9%; adjusted subdistribution hazard ratio, 3.210; 95% confidence interval, 1.286-8.013) compared with the Perimount Magna Ease cohort. Among 772 propensity score-matched pairs, at 7 years the Trifecta cohort had a higher risk of repeat aortic valve replacement for structural valve failure (5.7% vs 0%, P = .009)., Conclusions: The Trifecta aortic bioprosthesis is associated with a higher occurrence of repeat aortic valve replacement for structural valve failure compared with the Perimount Magna Ease bioprosthesis. Further comparative studies with echocardiographic data on structural valve deterioration and longer follow-up are needed to confirm these findings., (Copyright © 2020 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Paraplegia is one of the most severe complications occurring after the repair of thoracic and thoracoabdominal aortic aneurysms. Remote ischemic preconditioning (RIPC) has been shown to mitigate neurologic damage, and this study assessed its efficacy in preventing spinal cord ischemia., Methods: The study randomized 16 female pigs into an RIPC group (n = 8) and a control group (n = 8). The RIPC group underwent four cycles of 5-minute ischemia-reperfusion episodes by intermittent occlusion of the left iliac artery. All animals underwent systematic closure of the left subclavian artery and segmental arteries of the descending thoracic aorta to the level of diaphragm. Motor-evoked potential monitoring was performed in both hind limbs. Continuous electrocardiogram and hemodynamics were monitored, and pulmonary artery blood samples were collected. A neurologic assessment was performed 6 hours after the procedure. The thoracic and lumbar portions of the spinal cord were collected for histologic and immunohistochemical analysis., Results: The bilateral motor-evoked potential amplitude responses were higher in the RIPC group (p < 0.05) than in the control group; the difference was detected already before spinal cord ischemia. Paraplegia occurred in 1 control animal. Immunohistochemical total scores of antioxidant response regulator nuclear factor erythroid 2-related factor 2 were better in the RIPC group (11.0; range, 8.5 to 14.0) than in the control group (5.2; range, 1.0 to 9.0; p = 0.023)., Conclusions: RIPC induces electrophysiologic changes in the central nervous system that may confer spinal cord protection extending the resistance to ischemia. The significantly higher nuclear factor erythroid 2-related factor 2 scores suggest better neuronal cell protection against oxidative stress in the RIPC group., (Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: The aim of this study was to analyze early postoperative outcomes and 2-year survival after aortic valve replacement (AVR) with the sutureless Perceval bioprosthesis (Sorin Biomedica Cardio Srl, Salluggia, Italy) performed through ministernotomy compared with full sternotomy., Methods: This was a study of 267 consecutive patients who underwent isolated AVR with the sutureless Perceval bioprosthesis between 2007 and 2014 at 6 European centers. Of these, 189 (70.8%) were performed through ministernotomy and 78 through a full sternotomy. Propensity score matching was used to reduce selection bias., Results: In the overall cohort of ministernotomy and full sternotomy patients, in-hospital mortality was 1.1% and 2.6% and 2-year survival was 92% and 91%, respectively. Propensity score matching resulted in 56 pairs with similar characteristics and operative risk. Aortic cross-clamp (44 minutes in both groups, p = 0.931) and cardiopulmonary bypass time (69 vs 74 minutes, p = 0.363) did not differ between the groups. Apart from higher values in the ministernotomy group for postoperative peak gradients (28.1 vs 23.3 mm Hg, p = 0.026) and mean aortic valve gradients (15.2 vs 11.7 mm Hg, p = 0.011), early postoperative outcomes did not differ in the propensity-matched cohort. There were no differences in the in-hospital mortality rate or 2-year survival between the groups., Conclusions: AVR with the sutureless Perceval bioprosthesis through a ministernotomy was a safe and reproducible procedure that was not associated with prolonged aortic cross-clamp or cardiopulmonary bypass time compared with a full sternotomy. Early postoperative outcomes and 2-year survival were comparable between patients undergoing ministernotomy and full sternotomy., (Copyright © 2015 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: The use of minimized cardiopulmonary bypass (MCPB) circuits has recently increased in an attempt to reduce the adverse effects of CPB. This prospective randomized study aimed to determine the effects of MCPB on retinal microembolization and related inflammatory, coagulation, and endothelial markers compared with conventional extracorporeal circulation (CCPB) among patients undergoing coronary artery bypass graft surgery., Methods: Forty patients entered, and 37 patients completed the study. After the induction of anesthesia and immediately after the termination of CPB, standardized retinal fluorescein angiographs and digital images were obtained on both eyes and analyzed in a blinded fashion in terms of the CPB circuit. Blood samples for inflammatory, coagulation, and endothelial markers were collected at eight time points until the third postoperative day., Results: Postperfusion retinal fluorescein angiographs revealed microembolic perfusion defects in 2 of 18 in the MCPB group and in 9 of 18 in the CCPB group (p=0.027 [11% vs. 50%, difference 39%, confidence interval: 0.087 to 0.613, p=0.029]). Activation of polymorphonuclear leukocytes as measured with polymorphonuclear elastase was significantly decreased in the MCPB group. Other markers of inflammation, coagulation, and endothelial dysfunction increased comparably in both groups during CPB., Conclusions: Retinal microembolization was found to be decreased after the use of minimized CPB compared with CCPB, suggesting a decreased embolic load to the brain after MCPB., (Copyright © 2011 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Remote ischemic preconditioning is a novel method of reducing ischemia-reperfusion injury in which a transient ischemic period of the limb provides systemic protection against a prolonged ischemic insult. This method of preconditioning has shown some potential in ameliorating ischemia-related injury in various organs and experimental settings. We hypothesized that remote ischemic preconditioning might also improve the recovery from hypothermic circulatory arrest (HCA)., Methods: Twenty-four juvenile pigs underwent 60 minutes of HCA at 18 degrees C with either transient right hind leg ischemic preconditioning or no ischemic preconditioning. Preconditioning was induced by four cycles of 5-minute ischemia periods with three 5-minute reperfusion periods in between. Microdialysis and electroencephalography (EEG) data were recorded to detect any possible changes during the recovery phase., Results: The EEG data showed that the remote ischemic preconditioning group had significantly better EEG recovery time and a lower burst suppression ratio throughout the follow-up period. Cerebral extracellular glucose and glycerol content rose significantly immediately after HCA in the control group compared with the remote ischemic preconditioning group, and significantly higher lactate concentrations were measured in the control group at 5 and 6 hours after reperfusion, indicating a difference in cerebral metabolism., Conclusions: Our data imply that remote ischemic preconditioning improves the recovery from HCA. It provides a faster recovery of cortical neuronal activity and protection against potential oxygen radical-mediated ischemia damage during and after HCA. In addition, it seems to protect from a late phase lactate and pyruvate burst, mitigating possible damage from an anaerobic metabolism phase., (Copyright 2010 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.)

Background: Selective cerebral perfusion (SCP) is used for extending the period during which surgical procedures can be safely performed. We sought to determine the direct effects of pH management on cerebral microcirculation and metabolism during SCP., Methods: An experimental SCP porcine model was created by selectively allowing cold perfusate only into the bicarotid brachiocephalic trunk during the SCP period. Twenty-four piglets (6 to 8 weeks; mean weight, 26.1 +/- 4.1 kg) underwent 15-minute normothermic cardiopulmonary bypass, 45-minute cooling cardiopulmonary bypass, 60-minute SCP at 25 degrees C, and 45-minute rewarming cardiopulmonary bypass with either alpha-stat or pH-stat perfusion strategy randomly assigned. A cranial window was created over the parietal cortex for visualization of the cerebral vessels with intravital microscopy. Rhodamine-stained leukocytes were observed in cerebral postcapillary venules for adhesion and rolling. Microdialysis analysis was used for determination of brain metabolism., Results: Brain concentration of lactate was significantly higher in the alpha-stat group at 45 minutes of SCP, and at 15- and 45-minute rewarming intervals (p = 0.03; p = 0.003; and p = 0.05; respectively), reaching borderline statistical significance when assessed throughout the experiment (p = 0.06 for differences between groups). Further, at the end of cooling, the oxygen delivery tended to be higher in the pH-stat group (p = 0.07), whereas at the 30-minute rewarming interval, the oxygen extraction tended to be higher in the alpha-stat group (p = 0.06). There were no statistically significant differences between the groups in leukocyte-endothelial interaction, arterial diameter, or tissue oxygenation., Conclusions: The higher concentration of brain lactate and the tendency to higher oxygen extraction levels during rewarming with alpha-stat strategy suggests anaerobic metabolism occurred during SCP. No major differences between pH management strategies in cerebral microcirculation could be shown during SCP.

Background: The European system for cardiac operative risk evaluation score (EuroSCORE) has been shown to be of value in identifying patients at high risk for adverse immediate postoperative outcome after adult cardiac surgery. The aim of the present study was to evaluate EuroSCORE in predicting the 12-year outcome of patients who underwent on-pump coronary artery bypass surgery (CABG)., Methods: We calculated the EuroSCORE in 917 patients who underwent CABG. The median follow-up was 11.7 years., Results: Both additive and logistic EuroSCORE had an area under the receiver operating characteristic curve of 0.856 for prediction of 30-day postoperative death. Among 912 operative survivors, the 10-year survival rates according to quintiles of additive EuroSCORE were 87.9%, 83.9%, 85.2%, 76.0%, and 51.3% (p < 0.0001). The 10-year survival rates according to quintiles of logistic EuroSCORE were 87.9%, 85.4%, 86.5%, 76.9%, and 58.9% (p < 0.0001)., Conclusions: EuroSCORE is a relevant predictor of immediate and late outcome after on-pump CABG.

Background: Hypertonic saline dextran (HSD) has been shown to have neuroprotective properties. In the present study we have assessed its potential neuroprotective efficacy in the setting of hypothermic circulatory arrest in a surviving porcine model., Methods: Twenty-four pigs were randomized to receive two 5-minute intravenous infusions (4 mL/kg) of either HSD (7.5 % saline, 6% dextran 70) or normal saline immediately after and 4 hours after a 75-minute period of hypothermic circulatory arrest at a brain temperature of 18 degrees C., Results: The 7-day survival was 75% in the HSD group and 66% in the control group (p > 0.9). Brain total histopathologic score was lower in the HSD group (p = 0.01). Postoperative behavioral scores were higher in the HSD group on the second day after surgery (p = 0.03). Intracranial pressure was lower in the HSD group from 45 minutes to 8 hours after hypothermic circulatory arrest (p = 0.03). Cerebral perfusion pressure was higher in the HSD group from 45 minutes to 3 hours after hypothermic circulatory arrest (p = 0.06). Brain lactate concentration was lower in the HSD group when compared with controls (p = 0.05). Furthermore, brain glucose levels tended to be higher and brain lactate-pyruvate ratio and lactate-glucose ratio were lower in the HSD group. Brain tissue oxygen partial pressures were somewhat higher in the HSD group (p = 0.08)., Conclusions: The use of HSD in experimental hypothermic circulatory arrest is associated with significantly better neurologic recovery, better histopathology, lower intracranial pressure, higher cerebral perfusion pressure, and better preservation of brain metabolism.

Background: There is some evidence of beneficial metabolic effects associated with the pH-stat than with alpha-stat perfusion strategy, but this is tempered by a likely increased risk of embolism to the brain, especially in adult patients. We investigated this possible adverse effect in an experimental model that combined hypothermic circulatory arrest (HCA) and embolic brain injury., Methods: Twenty-four female juvenile pigs undergoing 25 minutes of HCA at a brain temperature of 18 degrees C were assigned to either alpha-stat (n = 12) or pH-stat (n = 12) strategy during cardiopulmonary bypass. Before the initiation of HCA, the descending aorta was clamped and 200 mg of albumin-coated polystyrene microspheres (250 to 750 microm in diameter) were injected into the isolated aortic arch in both groups., Results: The 7-day survival rate was 75% in the pH-stat group and 50% in the alpha-stat group (p = 0.40). The pH-stat group had significantly better behavioral scores on postoperative days 5 (p = 0.03) and 6 (p = 0.04). The pH-stat strategy was associated with better postoperative intracranial pressures and histopathologic scores, but such differences did not reach statistical significance. The alpha-stat group had lower brain glucose concentrations postoperatively as well as higher brain lactate/glucose and lactate/pyruvate ratios, Conclusions: These results suggest that pH-stat strategy does not cause any worse brain injury than the alpha-stat strategy. Indeed, the pH-stat strategy is associated with a slightly better outcome compared with the alpha-stat strategy, even in the setting of cerebral embolization. This observation suggests that the pH-stat strategy could also be used in adults during deep hypothermic cardiopulmonary bypass despite the increased risk of intraoperative cerebral embolization.

Background: Atrial fibrillation, occurring after coronary artery bypass grafting (CABG), has been suggested to be associated with the development of postoperative stroke. However, it is not clear what is the incidence of atrial fibrillation-related postoperative stroke, the timing of its occurrence, and the outcome. These issues have been investigated in a consecutive series of patients who have undergone on-pump coronary artery bypass grafting (ONCAB)., Methods: Among 2,630 patients who underwent ONCAB, 52 patients (2.0%) experienced postoperative stroke and form the basis of the present study., Results: Twelve patients (23.1%) died postoperatively. The ischemic cerebral event occurred after a mean of 3.7 days (range, 0 to 33). In 19 patients (36.5%), atrial fibrillation preceded the occurrence of neurologic complication. These patients experienced a mean of 2.5 episodes of atrial fibrillation before the occurrence of neurologic complication. The cerebrovascular event occurred after a mean of 6.0 days in patients in whom atrial fibrillation preceded it, after a mean of 1.2 days in those with calcified ascending aorta, and after a mean of 3.1 days in those without calcified ascending aorta or in whom atrial fibrillation did not precede the cerebrovascular complication (p < 0.0001). Stroke occurred a mean of 21.3 hours after atrial fibrillation., Conclusions: This study confirmed that atrial fibrillation, occurring after CABG, is a major determinant of postoperative stroke. Prevention of postoperative atrial fibrillation, and of formation of clots into the left atrium, may dramatically reduce the risk of postoperative stroke.

Background: The superiority of the pH-stat to the alpha-stat acid-base strategy during cardiopulmonary bypass as a neuroprotective method during hypothermic circulatory arrest is still controversial. In the present study, brain metabolism and outcome have been evaluated in a surviving model of experimental hypothermic circulatory arrest., Methods: Twenty pigs undergoing 75-minutes of hypothermic circulatory arrest at a brain temperature of 18 degrees C were randomly assigned to the alpha-stat (n = 10) or pH-stat (n = 10) strategy during cardiopulmonary bypass., Results: The 7-day survival rate was 90% (9 of 10) in the pH-stat group and 10% (1 of 10) in the alpha-stat group. At the end of cooling, pH-stat strategy was associated with significantly lower brain lactate and pyruvate concentrations and brain lactate-glucose ratio. After reperfusion, brain concentrations of glycerol, lactate, pyruvate, and lactate-glucose ratio were significantly lower in the pH-stat group. This strategy was associated with a faster rise of brain tissue temperature and reoxygenation on reperfusion, which is likely secondary to improved cerebral perfusion., Conclusions: During cardiopulmonary bypass before and after a period of hypothermic circulatory arrest, acid-base management according to the pH-stat principles seemed to be associated with less derangements in cerebral metabolism, lower intracranial pressures, and excellent behavioral recovery and survival outcome. Because there is strong evidence of the beneficial metabolic effects related to this method, further studies using an experimental model of combined HCA and embolic brain injury are required to exclude a possible increased risk of cerebral embolism associated with the pH-stat strategy.

Background: Lamotrigine and leukocyte filtration seem to improve cerebral protection during experimental hypothermic circulatory arrest (HCA). This study was performed to evaluate whether their combined use may further improve cerebral protection., Methods: Twenty-four pigs undergoing 75-minute period of HCA at 20 degrees C were randomly assigned to receive saline; lamotrigine (20 mg/kg) before HCA (L); or lamotrigine (20 mg/kg) before HCA plus leukocyte filtration before and after HCA (L + LF)., Results: Seven animals (87%) in the L + LF group, 4 (50%) in the L group, and 3 (37%) in the control group were alive on the seventh postoperative day. The median electroencephalogram burst recovery was 94% in the L + LF group (p = 0.024 versus control group), 81% in the L group, and 64% in the control group. Among the surviving animals, the median behavioral scores were 9, 9, and 6 at the seventh day, respectively (p = 0.005 between the L + LF group and the control group). The median histopathologic score was 14 in the L + LF group (p = 0.046 versus control group), 14.5 in the L group (p = 0.062 versus control group), and 21 in the control group., Conclusions: Lamotrigine has neuroprotective effect during HCA. The combined use of lamotrigine and LF may further improve the survival outcome.

Background: The pig has become an increasingly popular model for the study of cerebral protection during cardiothoracic surgery in recent years, but little information is available concerning hypothermic porcine physiology. Because the efficacy of cerebral protection depends largely upon metabolic suppression, we studied cerebral oxygen metabolism at various temperatures using two different methods to assess cerebral blood flow (CBF)., Material and Methods: Twelve pigs (7 to 13 kg) underwent cooling on cardiopulmonary bypass to 8 degrees C as recorded by an electrode placed deep in the parenchyma of the brain. CBF was measured in 6 animals using radioactive microspheres and in the other 6 using fluorescent microspheres. CBF, cerebral oxygen consumption, and cerebral vascular resistance were determined at 37 degrees C, 28 degrees C, 18 degrees C, and 8 degrees C., Results: Both methods produced very similar data. CBF fell steadily with decrease in temperature to 18 degrees C but failed to drop further with more profound hypothermia. With both groups combined, mean cerebral oxygen metabolism was 2.63 mL/100 g per minute at 37 degrees C. Metabolic activity was 50% of base line values at 28 degrees C, 19% at 18 degrees C, and 11% at 8 degrees C. The Q10 value in the pig--the degree of metabolic suppression achieved by a 10 degrees C drop in temperature--is 2.46 (95% confidence interval 2.1 to 2.9); this value is consistent with similar studies in humans., Conclusions: The presence of significant residual metabolic activity at 18 degrees C suggests that this degree of hypothermia may provide incomplete cerebral protection during prolonged interruption of CBF. This study demonstrates that cooling to temperatures below 18 degrees C in the pig can achieve greater metabolic suppression although it may be associated with loss of cerebral autoregulation.

Background: Hypothermic circulatory arrest (HCA) is used in surgery for aortic and congenital cardiac diseases. Although studies of the safety of HCA in animals have been carried out, the degree to which metabolism is suppressed in patients during hypothermia has been difficult to determine because of problems with serial measurements of cerebral blood flow in the clinical setting., Methods: To quantify the degree of metabolic suppression achieved by hypothermia, we studied 37 adults undergoing operations employing HCA. Cerebral blood flow was estimated using an ultrasonic flow probe on the left common carotid artery, and cerebral arteriovenous oxygen content differences were calculated from jugular venous bulb and arterial oxygen saturations. Cerebral metabolic rates while cooling were then ascertained. The temperature coefficient, Q10, which is the ratio of metabolic rates at temperatures 10 degrees C apart, was determined., Results: The human cerebral Q10 was found to be 2.3. The cerebral metabolic rate is still 17% of baseline at 15 degrees C. If one assumes that cerebral blood flow can safely be interrupted for 5 min at 37 degrees C, and that cerebral metabolic suppression accounts for the protective effects of hypothermia, the predicted safe duration of HCA at 15 degrees C is only 29 min., Conclusions: The safe intervals calculated from measured cerebral oxygen consumption suggest that shorter intervals and lower temperatures than those currently used may be necessary to assure adequate cerebral protection during hypothermic circulatory arrest.

Background: Reoperative median sternotomy can result in cardiac injury and serious bleeding, with the rate ranging from 2% to 6%. Closure of the native pericardium can maintain a preventing plane of cleavage. In patients in whom primary pericardial closure is not possible, several substitutes have been tried with variable results. We conducted a prospective study to evaluate the clinical feasibility of polytetrafluoroethylene and polyglycolic acid patches as pericardial substitutes, using computed tomography for imaging the postoperative state of the retrosternal space., Methods: The basic population comprised 540 patients who were scheduled for coronary artery bypass grafting, and 52 of them who met the research criteria were chosen for computed tomographic evaluation after 5 years after the primary operation., Results: As a substitute, polytetrafluoroethylene seemed to be less adhesive to the posterior surface of the sternum. Total adhesion scores were also statistically significant (p < 0.001) to the advantage of polytetrafluoroethylene over polyglycolic acid as a pericardial substitute., Conclusions: Polytetrafluoroethylene membrane seems to be capable of minimizing retrosternal adhesion formation and thus it may protect the heart during subsequent reoperative sternotomy.

Background: This study was undertaken to confirm earlier findings that retrograde cerebral perfusion (RCP) can improve cerebral outcome after prolonged hypothermic circulatory arrest (HCA), and to determine whether RCP with inferior vena caval occlusion, which is more effective in removing particulate emboli, is superior to conventional RCP in enhancing cerebral protection., Methods: Sixty-two pigs (27 to 30 kg) were randomly assigned to undergo one of the following for 90 minutes at 20 degrees C: antegrade cerebral perfusion (ACP); conventional RCP (RCP); RCP with occlusion of the inferior vena cava (RCP-O), or HCA with the head packed in ice. RCP flow was regulated to a sagittal sinus pressure of 20 mm Hg. Hemodynamic, electrophysiologic, and metabolic monitoring were carried out until 4 hours after rewarming, daily behavioral and neurologic assessments until elective sacrifice on day 7, and histologic analysis of the brain after death., Results: Complete behavioral recovery was seen in all surviving animals by day 5 after ACP or RCP, but in only 83% after RCP-O and 50% after HCA (p = 0.001). A histopathologic score of 2 or more, indicating more than mild injury, was not found in any animal after ACP, in 27% after RCP, in 47% after HCA, and in 68% after RCP-O (p = 0.002). The median oxygen consumption was 6.66 mL/min after ACP, 1.37 mL/min with RCP, and 1.02 mL/min with RCP-O (p < 0.0001). The median amount of fluid sequestered was 2,450 mL after RCP-O, 760 mL after RCP, and -200 mL after ACP (p < 0.0001)., Conclusions: Conventional RCP without inferior vena caval occlusion results in a significantly better outcome than RCP-O after prolonged HCA, despite more efficient cerebral perfusion during RCP-O, and also provides cerebral protection superior to prolonged HCA alone, but care must be taken during its implementation to minimize cerebral edema and other possible causes of retroperfusion-related cerebral injury.

Background: The decision whether or not to recommend resection of moderately large descending thoracic and thoracoabdominal aneurysms requires weighing the relatively high mortality and significant risk of paraplegia associated with operation against the likelihood that the aneurysm will rupture spontaneously, with an almost invariably fatal outcome. To better define the risk of aneurysm rupture, we undertook a prospective study of patients who had not had operation on their moderately large descending thoracic and thoracoabdominal aneurysms., Methods: Patients were enrolled at the time of their second computed tomographic scans: three-dimensional computer-generated reconstructions allowed determination of several dimensional parameters for each study, including diameters and cross-sectional areas at the site of maximal dilatation in the descending aorta and in the abdomen as well as total thoracoabdominal surface area. Comparisons of serial studies permitted calculation of yearly rates of change in these dimensions., Results: Of 114 patients, 8 died of causes unrelated to the aneurysm, 26 died of rupture, 20 met previously determined criteria for operation, and 60 survived without operation or rupture. Multivariate regression analysis identified maximal diameter in the descending and in the abdominal aorta as independent risk factors for rupture, as well as older age, the presence of even uncharacteristic pain, and a history of chronic obstructive pulmonary disease. A piecewise exponential model enabled construction of an equation allowing calculation of rate of rupture in patients in whom the values of the risk factors are known, and also of the probability of rupture in a given individual over a specified time interval., Conclusions: Because using this equation--based on easily determined risk factors (age, pain, chronic obstructive pulmonary disease, maximal thoracic and maximal abdominal aortic diameter)--allows the risk of aneurysm rupture within a given interval to be estimated fairly accurately for each individual patient, it is our current practice to recommend operation when the calculated risk of rupture within 1 year exceeds the anticipated mortality of elective operation, rather than relying on general operative guidelines based almost exclusively on aneurysm size.

A case of bilateral spontaneous pneumothorax with critical collapse of both lungs in a previously healthy 19-year-old woman is described. A congenital defect of mediastinal septum was suspected on the basis of roentgenographic findings and confirmed by right-sided thoracotomy. This mediastinal window between the pleural spaces allowed air leaking from a ruptured right lung apical bulla to collapse not only the right lung but also the left. Apical TA stapler resection and right-sided parietal pleurectomy was performed to prevent recurrence.