The Society of Thoracic Surgeons, The Society of Cardiovascular Anesthesiologists, and The American Society of ExtraCorporeal Technology: Clinical Practice Guidelines-Anticoagulation During Cardiopulmonary Bypass.

Despite more than a half century of "safe" cardiopulmonary bypass (CPB), the evidence base surrounding the conduct of anticoagulation therapy for CPB has not been organized into a succinct guideline. For this and other reasons, there is enormous practice variability relating to the use and dosing of heparin, monitoring heparin anticoagulation, reversal of anticoagulation, and the use of alternative anticoagulants. To address this and other gaps, The Society of Thoracic Surgeons, the Society of Cardiovascular Anesthesiologists, and the American Society of Extracorporeal Technology developed an Evidence Based Workgroup. This was a group of interdisciplinary professionals gathered to summarize the evidence and create practice recommendations for various aspects of CPB. To date, anticoagulation practices in CPB have not been standardized in accordance with the evidence base. This clinical practice guideline was written with the intent to fill the evidence gap and to establish best practices in anticoagulation therapy for CPB using the available evidence. To identify relevant evidence, a systematic review was outlined and literature searches were conducted in PubMed using standardized medical subject heading (MeSH) terms from the National Library of Medicine list of search terms. Search dates were inclusive of January 2000 to December 2015. The search yielded 833 abstracts, which were reviewed by two independent reviewers. Once accepted into the full manuscript review stage, two members of the writing group evaluated each of 286 full papers for inclusion eligibility into the guideline document. Ninety-six manuscripts were included in the final review. In addition, 17 manuscripts published before 2000 were included to provide method, context, or additional supporting evidence for the recommendations as these papers were considered sentinel publications. Members of the writing group wrote and developed recommendations based on review of the articles obtained and achieved more than two thirds agreement on each recommendation. The quality of information for a given recommendation allowed assessment of the level of evidence as recommended by the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Recommendations were written in the three following areas: (1) heparin dosing and monitoring for initiation and maintenance of CPB; (2) heparin contraindications and heparin alternatives; and (3) reversal of anticoagulation during cardiac operations. It is hoped that this guideline will serve as a resource and will stimulate investigators to conduct more research and to expand on the evidence base on the topic of anticoagulation therapy for CPB.

The Society of Thoracic Surgeons, The Society of Cardiovascular Anesthesiologists, and The American Society of ExtraCorporeal Technology: Clinical Practice Guidelines for Cardiopulmonary Bypass--Temperature Management During Cardiopulmonary Bypass.

UNLABELLED: In order to improve our understanding of the evidence-based literature supporting temperature management during adult cardiopulmonary bypass, The Society of Thoracic Surgeons, the Society of Cardiovascular Anesthesiology and the American Society of ExtraCorporeal Technology tasked the authors to conduct a review of the peer-reviewed literature, including: 1) optimal site for temperature monitoring, 2) avoidance of hyperthermia, 3) peak cooling temperature gradient and cooling rate, and 4) peak warming temperature gradient and rewarming rate. Authors adopted the American College of Cardiology/American Heart Association method for development clinical practice guidelines, and arrived at the following recommendations: CLASS I RECOMMENDATIONS: a)The oxygenator arterial outlet blood temperature is recommended to be utilized as a surrogate for cerebral temperature measurement during CPB. (Class I, Level C) b)To monitor cerebral perfusate temperature during warming, it should be assumed that the oxygenator arterial outlet blood temperature under-estimates cerebral perfusate temperature. (Class I, Level C) c)Surgical teams should limit arterial outlet blood temperature to<37°C to avoid cerebral hyperthermia. (Class 1, Level C) d)Temperature gradients between the arterial outlet and venous inflow on the oxygenator during CPB cooling should not exceed 10°C to avoid generation of gaseous emboli. (Class 1, Level C) e)Temperature gradients between the arterial outlet and venous inflow on the oxygenator during CPB rewarming should not exceed 10°C to avoid out-gassing when blood is returned to the patient. (Class 1, Level C) CLASS IIa RECOMMENDATIONS: a)Pulmonary artery or nasopharyngeal temperature recording is reasonable for weaning and immediate post-bypass temperature measurement. (Class IIa, Level C)b)Rewarming when arterial blood outlet temperature ≥30° C: i.To achieve the desired temperature for separation from bypass, it is reasonable to maintain a temperature gradient between arterial outlet temperature and the venous inflow of≤4°C. (Class IIa, Level B) ii.To achieve the desired temperature for separation from bypass, it is reasonable to maintain a rewarming rate≤0.5°C/min. (Class IIa, Level B) NO RECOMMENDATION: No recommendation for a guideline is provided concerning optimal temperature for weaning from CPB due to insufficient published evidence.

The Society of Thoracic Surgeons, The Society of Cardiovascular Anesthesiologists, and The American Society of ExtraCorporeal Technology: Clinical Practice Guidelines for Cardiopulmonary Bypass--Temperature Management during Cardiopulmonary Bypass.

To improve our understanding of the evidence-based literature supporting temperature management during adult cardiopulmonary bypass, The Society of Thoracic Surgeons, the Society of Cardiovascular Anesthesiology and the American Society of ExtraCorporeal Technology tasked the authors to conduct a review of the peer-reviewed literature, including 1) optimal site for temperature monitoring, 2) avoidance of hyperthermia, 3) peak cooling temperature gradient and cooling rate, and 4) peak warming temperature gradient and rewarming rate. Authors adopted the American College of Cardiology/American Heart Association method for development clinical practice guidelines, and arrived at the following recommendation.

Attenuating the Systemic Inflammatory Response to Adult Cardiopulmonary Bypass: A Critical Review of the Evidence Base.

A wide range of pharmacological, surgical, and mechanical pump approaches have been studied to attenuate the systemic inflammatory response to cardiopulmonary bypass, yet no systematically based review exists to cover the scope of anti-inflammatory interventions deployed. We therefore conducted an evidence-based review to capture "self-identified" anti-inflammatory interventions among adult cardiopulmonary bypass procedures. To be included, trials had to measure at least one inflammatory mediator and one clinical outcome, specified in the "Outcomes 2010" consensus statement. Ninety-eight papers satisfied inclusion criteria and formed the basis of the review. The review identified 33 different interventions and approaches to attenuate the systemic inflammatory response. However, only a minority of papers (35 of 98 [35.7%]) demonstrated any clinical improvement to one or more of the predefined outcome measures (most frequently myocardial protection or length of intensive care unit stay). No single intervention was supported by strong level A evidence (multiple randomized controlled trials [RCTs] or meta-analysis) for clinical benefit. Interventions at level A evidence included off-pump surgery, minimized circuits, biocompatible circuit coatings, leukocyte filtration, complement C5 inhibition, preoperative aspirin, and corticosteroid prophylaxis. Interventions at level B evidence (single RCT) for minimizing inflammation included nitric oxide donors, C1 esterase inhibition, neutrophil elastase inhibition, propofol, propionyl-L-carnitine, and intensive insulin therapy. A secondary analysis revealed that suppression of at least one inflammatory marker was necessary but not sufficient to confer clinical benefit. The most effective interventions were those that targeted multiple inflammatory pathways. These observations are consistent with a "multiple hit" hypothesis, whereby clinically effective suppression of the systemic inflammatory response requires hitting multiple inflammatory targets simultaneously. Further research is warranted to evaluate if combinations of interventions that target multiple inflammatory pathways are capable of synergistically reducing inflammation and improving outcomes after cardiopulmonary bypass.

Factor IX complex for the treatment of severe bleeding after cardiac surgery.

BACKGROUND: Previous reports have been published on the use of recombinant Factor VIIa for intractable bleeding after cardiac surgery; however, there is limited information on the use of Factor IX Complex in this population. METHODS: A retrospective cohort study of adult patients who underwent cardiac surgery and experienced severe postoperative bleeding, defined as a mean chest tube output ≥300 mL/h. Primary outcomes were changes in chest tube output and blood product usage pre- and post-Factor IX Complex administration. RESULTS: Eleven patients received Factor IX Complex for severe postoperative bleeding. The mean dose of Factor IX Complex was 35 (13-52) units/kg. Chest tube output was significantly reduced after Factor IX Complex administration (mean pre-Factor IX Complex 381 ± 49 mL/h, mean post-Factor IX Complex 151 ± 38 mL/h; P = 0.003). Blood product usage decreased after Factor IX Complex but was not statistically significant (mean pre-Factor IX Complex 373 ± 81 mL/h, mean post-Factor IX Complex 212 ± 48 mL/h; P = 0.669). Adverse events included 1 pulmonary embolism (postoperative day 43) and 2 episodes of acute renal failure requiring dialysis (postoperative days 2 and 5). CONCLUSIONS: In this small group of patients, Factor IX Complex effectively controlled severe bleeding after cardiac surgery preventing the need for re-exploration.

Brain protection during cardiac surgery: circa 2012.

Brain injury during cardiac surgery can cause a potentially disabling syndrome consisting mainly of cognitive dysfunction but can manifest itself as symptoms and signs indistinguishable from frank stroke. The cause of the damage is mainly the result of emboli consisting of solid material such as clots or atherosclerotic plaque, fat, and/or gas. These emboli enter the cerebral circulation from the cardiopulmonary bypass machine, break off the aorta during manipulation, and enter the circulation from cardiac chambers. This damage can be prevented or at least minimized by avoiding aortic manipulation, filtering aortic inflow from the pump, preventing air from entering the pump plus careful deairing of the heart. Shed blood from the cardiotomy suction should be processed by a cell saver whenever possible. By doing these maneuvers, inflammation of the brain can be avoided. Long-term neurocognitive damage has been largely prevented in large series of patients having high-risk surgery, which makes these preventive measures worthwhile.

Cannula design reduces particulate and gaseous emboli during cardiopulmonary bypass for coronary revascularization.

PURPOSE: The incidence of neurocognitive deficits after coronary bypass surgery remains problematic, with atheroembolism being one of the major causes. External manipulation of aorta and the "sandblasting" effect of the high-velocity perfusion jet can cause dislodgement of atheromatous debris. DESCRIPTION: A new arterial cannula features a tip configuration that diffuses the flow through multiple outlets, providing reduced velocity and shear with one central and three diverted flow streams. EVALUATION: Between March 2007 and July 2008 twenty patients having isolated coronary artery bypass operations were instrumented with an Embolus Detection and Classification transducer. These data were compared to 43 patients from a previous study using similar techniques except for a standard open-tip arterial cannula. Total embolic counts were markedly lower in the new cannula group (20±25 vs 174±378) as were both gaseous (11±15 vs 95±211) and particulate counts (9±11 vs 80±194). CONCLUSIONS: The select 3D cannula design reduces the sandblasting effect of the perfusion jet and, also, may direct emboli from the heart and cardiopulmonary bypass equipment away from the cerebral circulation.

Reduction of myocardial ischemia-reperfusion injury by mechanical tissue resuscitation using sub-atmospheric pressure.

BACKGROUND: Reperfusion-induced injury after myocardial infarction is associated with a well-defined sequence of early and late cardiomyocyte death. Most present attempts to ameliorate this sequence focus on a single facet of the complex process in an attempt to salvage cardiomyocytes. We examined, as proof of concept, the effects of mechanical tissue resuscitation (MTR) with controlled negative pressure on myocardial injury following acute myocardial infarction. METHODS: Anesthetized swine were subjected to 75 minutes of left coronary artery occlusion and three hours of reperfusion. Animals were assigned to one of three groups: (A) untreated control; treatment of involved myocardium for 180 minutes of MTR with (B) -50 mmHg, or (C) -125 mmHg. RESULTS: All three groups were subjected to equivalent ischemic stress. Treatment of the ischemic area with MTR for 180 minutes significantly (p < 0.001) reduced infarct size (area of necrosis/area at risk) in both treatment groups compared to control: 9.3 +/- 1.8% (-50 mmHg) and 11.9 +/- 1.2% (-125 mmHg) versus 26.4 +/- 2.1% (control). Total area of cell death was reduced by 65% with -50 mmHg treatment and 55% in the -125 mmHg group. CONCLUSIONS: Treatment of ischemic myocardium with MTR, for a controlled period of time during reperfusion, successfully reduced the extent of myocardial death after acute myocardial infarction. These data provide evidence that MTR using subatmospheric pressure may be a simple, efficacious, nonpharmacological, mechanical strategy for decreasing cardiomyocyte death following myocardial infarction, which can be delivered in the operating room.

Consensus statement: minimal criteria for reporting the systemic inflammatory response to cardiopulmonary bypass.

The lack of established cause and effect between putative mediators of inflammation and adverse clinical outcomes has been responsible for many failed anti-inflammatory interventions in cardiopulmonary bypass (CPB). Candidate interventions that impress in preclinical trials by suppressing a given inflammation marker might fail at the clinical trial stage because the marker of interest is not linked causally to an adverse outcome. Alternatively, there exist examples in which pharmaceutical agents or other interventions improve clinical outcomes but for which we are uncertain of any antiinflammatory mechanism. The Outcomes consensus panel made 3 recommendations in 2009 for the conduct of clinical trials focused on the systemic inflammatory response. This panel was tasked with updating, as well as simplifying, a previous consensus statement. The present recommendations for investigators are the following: (1) Measure at least 1 inflammation marker, defined in broad terms; (2) measure at least 1clinical end point, drawn from a list of practical yet clinically meaningful end points suggested by the consensus panel; and(3) report a core set of CPB and perfusion criteria that maybe linked to outcomes. Our collective belief is that adhering to these simple consensus recommendations will help define the influence of CPB practice on the systemic inflammatory response, advance our understanding of causal inflammatory mechanisms, and standardize the reporting of research findings in the peer-reviewed literature.

Effects of a waiting period after clopidogrel treatment before performing coronary artery bypass grafting.

STUDY OBJECTIVE: To assess the effects of a waiting period after clopidogrel treatment before coronary artery bypass grafting (CABG). Design. Single-center, prospective, observational study. SETTING: Cardiothoracic surgery intensive care unit at a university-affiliated medical center. PATIENTS: One hundred consecutive patients who received clopidogrel and were scheduled to undergo primary CABG. In 64 of these patients, CABG was delayed at least 5 days after clopidogrel treatment (group A). The other 36 patients received clopidogrel treatment within 5 days of undergoing CABG (group B). MEASUREMENTS AND MAIN RESULTS: Data were collected on patient demographics, time of last clopidogrel dose, preoperative anticoagulant and/or antiplatelet agents administered, surgical characteristics, intraoperative transfusions, blood products transfused, and chest tube output for 24 hours after surgery. No significant differences in baseline characteristics or intraoperative variables (number of bypasses, aortic cross-clamp time, and cardiopulmonary bypass time) were noted between the two groups. Mean +/- SD number of packed red blood cell units/patient was 1.1 +/- 1.4 in group A versus 2.1 +/- 2.5 in group B (p=0.009). Mean +/- SD number of platelet units/patient transfused was 0.5 +/- 0.9 in group A versus 1.9 +/- 1.6 in group B (p<0.001). When comparing a subset of 21 patients who received clopidogrel within 72 hours of surgery with the 64 whose CABG was delayed at least 5 days after clopidogrel treatment, the transfusion rates were significantly higher (95% vs 52%, p<0.05). Specifically, the mean +/- SD number of transfused units/patient of red blood cells (3.1 +/- 2.8 vs 1.1 +/- 1.4, p<0.005) and platelets (2.6 +/- 1.5 vs 0.5 +/- 0.9, p<0.007) was greater in patients who received clopidogrel within 72 hours of surgery. CONCLUSION: A strategy to delay CABG after clopidogrel treatment led to reduced blood product administration. The optimal waiting period after clopidogrel treatment is not known but appears to be at least 5 days before CABG.

The Society of Thoracic Surgeons, The Society of Cardiovascular Anesthesiologists, and The American Society of ExtraCorporeal Technology: Clinical Practice Guidelines-Anticoagulation During Cardiopulmonary Bypass.

Despite more than a half century of "safe" cardiopulmonary bypass (CPB), the evidence base surrounding the conduct of anticoagulation therapy for CPB has not been organized into a succinct guideline. For this and other reasons, there is enormous practice variability relating to the use and dosing of heparin, monitoring heparin anticoagulation, reversal of anticoagulation, and the use of alternative anticoagulants. To address this and other gaps, The Society of Thoracic Surgeons, the Society of Cardiovascular Anesthesiologists, and the American Society of Extracorporeal Technology developed an Evidence Based Workgroup. This was a group of interdisciplinary professionals gathered to summarize the evidence and create practice recommendations for various aspects of CPB. To date, anticoagulation practices in CPB have not been standardized in accordance with the evidence base. This clinical practice guideline was written with the intent to fill the evidence gap and to establish best practices in anticoagulation therapy for CPB using the available evidence. To identify relevant evidence, a systematic review was outlined and literature searches were conducted in PubMed using standardized medical subject heading (MeSH) terms from the National Library of Medicine list of search terms. Search dates were inclusive of January 2000 to December 2015. The search yielded 833 abstracts, which were reviewed by two independent reviewers. Once accepted into the full manuscript review stage, two members of the writing group evaluated each of 286 full papers for inclusion eligibility into the guideline document. Ninety-six manuscripts were included in the final review. In addition, 17 manuscripts published before 2000 were included to provide method, context, or additional supporting evidence for the recommendations as these papers were considered sentinel publications. Members of the writing group wrote and developed recommendations based on review of the articles obtained and achieved more than two thirds agreement on each recommendation. The quality of information for a given recommendation allowed assessment of the level of evidence as recommended by the American College of Cardiology Foundation/American Heart Association Task Force on Practice Guidelines. Recommendations were written in the three following areas: (1) heparin dosing and monitoring for initiation and maintenance of CPB; (2) heparin contraindications and heparin alternatives; and (3) reversal of anticoagulation during cardiac operations. It is hoped that this guideline will serve as a resource and will stimulate investigators to conduct more research and to expand on the evidence base on the topic of anticoagulation therapy for CPB.

The Society of Thoracic Surgeons, The Society of Cardiovascular Anesthesiologists, and The American Society of ExtraCorporeal Technology: Clinical Practice Guidelines for Cardiopulmonary Bypass--Temperature Management During Cardiopulmonary Bypass.

In order to improve our understanding of the evidence-based literature supporting temperature management during adult cardiopulmonary bypass, The Society of Thoracic Surgeons, the Society of Cardiovascular Anesthesiology and the American Society of ExtraCorporeal Technology tasked the authors to conduct a review of the peer-reviewed literature, including: 1) optimal site for temperature monitoring, 2) avoidance of hyperthermia, 3) peak cooling temperature gradient and cooling rate, and 4) peak warming temperature gradient and rewarming rate. Authors adopted the American College of Cardiology/American Heart Association method for development clinical practice guidelines, and arrived at the following recommendations: No Recommendation No recommendation for a guideline is provided concerning optimal temperature for weaning from CPB due to insufficient published evidence.

Rapid disappearance of protamine in adults undergoing cardiac operation with cardiopulmonary bypass.

BACKGROUND: Despite long use of protamine in cardiac operations, neither protamine concentrations nor pharmacokinetics have been reported in patients. METHODS: Twenty-eight patients (age, 26 to 80 years) undergoing various cardiac surgical procedures gave their consent to receive 250 mg of protamine sulfate administered intravenously by an infusion pump during 5 minutes. Protamine was administered at the usual intraoperative time after separation from cardiopulmonary bypass for reversal of heparin. Timed arterial blood samples were obtained after protamine infusion. Blood plasma was subjected to solid-phase extraction and high-performance liquid chromatography. Total (free + heparin-bound) protamine concentration versus time data were subjected to pharmacokinetic modeling. RESULTS: Twenty-six patients completed the study. Total plasma protamine concentrations declined rapidly. Model-independent pharmacokinetic analysis revealed median (range) values as follows: volume of distribution, 5.4 L (0.82 to 34 L); clearance, 1.4 L/min (0.61 to 3.8 L/min); and half-life, 4.5 min (1.9 to 18 min). Schwarz-Bayesian criterion identified a two-compartment exponential model with adjustment for weight in the central compartment volume of distribution as performing better than other compartmental or Michaelis-Menten models. CONCLUSIONS: Protamine has a very short (approximately 5 minutes) half-life after a single 250-mg dose in adult patients. This short half-life could underlie recurrent anticoagulation after initial apparent reversal of heparin.

The first successful repair of postinfarction ventricular septal defect: influence of good fortune, team work, and an inquisitive mind.

Research in our institution identified the first case in which cardiopulmonary bypass was utilized. By happenstance, it turned out to be the presumed first repair of postinfarction ventricular septal defect. The circumstances of this interesting case are presented and discussed in the context of our surgical heritage.

Results of valve replacement with Omniscience mechanical prostheses.

BACKGROUND: The Omniscience mechanical valve has been the subject of multiple clinical investigations with variable results, including reports of high complication and reoperation rates. METHODS: Records of all patients who received Omniscience valves were reviewed, and follow-up interviews were conducted to determine the incidence of valve-related morbidity, mortality, and functional results. Incidence of complications was expressed as events per 100 patient-years follow-up. Survival and freedom from valve-related complications and mortality were calculated using a product limit method. RESULTS: Between 1984 and 1988, 192 patients received 213 Omniscience valves [93 mitral (M), 79 aortic (A), and 20 multiple (D) valve replacements]. Perioperative mortality was 9%. The incidence of major valve-related morbidity was as follows: thrombosis, 1.30 M, 0.17 A, 0.72 D; endocarditis, 0.48 M, 0.18 A, 0 D; hemorrhagic, 4.67 M, 2.84 A, 5.00 D; embolic, 2.90 M, 2.27 A, 1.57 D; nonstructural dysfunction, 1.66 M, 1.08 A, 2.27 D; reoperation, 4.02 M, 1.99 A, 6.48 D. All explanted valves (n = 43) were examined, and 40% (n = 17) were found to have limited disc excursion in the absence of thrombus. Freedom from valve-related morbidity, mortality, or reoperation at 10 years was 22% for mitral, 39% for aortic, and 17% for multivalve replacements. At follow-up, only 73% of patients were New York Heart Association class I or II. Five- and 10-year estimated survivals were 72% and 55% for M, 80% and 51% for A, and 65% and 50% for D replacements. CONCLUSIONS: Use of the Omniscience valve provided poor functional improvement and a significant incidence of valve-related complications, including the need for reoperation.

Initial experience with the Toronto Root bioprosthesis.

BACKGROUND AND AIM OF THE STUDY: The study aim was to assess the safety and efficacy of the Toronto Root bioprosthesis for aortic root or valve replacement during the early postoperative stages. METHODS: Between November 2000 and December 2002, the Toronto Root was implanted in 191 patients in 17 institutions. The patients' mean age was 65 years (range: 25 to 87 years) and 70% were males. The bioprosthesis was implanted as a full aortic root in 76% of patients, as a root inclusion in 9%, and in the subcoronary position in 15%. The sizes used in decreasing frequency were 27, 29, 25, 23 and 21 mm. Coronary artery bypass was performed in 25% of patients. Echocardiography was performed before hospital discharge and at six months postoperatively. Serum aluminum levels were monitored pre- and postoperatively as this metal is used in anticalcification treatment of the arterial wall of the porcine root. For the purpose of this study, follow up was closed at six months in all patients, and was complete. RESULTS: Eight patients died, though none of the deaths was valve-related. Two patients required reoperation because of technical errors during implantation. Two patients developed endocarditis, one patient required surgical intervention, and two patients suffered cerebral transient ischemic attacks. All survivors experienced symptomatic improvement, and 97% were in NYHA functional classes I and II at six months postoperatively. Blood levels of aluminum were unchanged at follow up. The mean effective orifice area of all valves studied was 2.0 +/- 0.8 cm2, and the mean systolic gradient 7.0 +/- 3.9 mmHg at six months postoperatively. No patient had more than trace aortic insufficiency. CONCLUSION: Early experience with the Toronto Root bioprosthesis has shown it to be a safe and effective valve for aortic valve or aortic root replacement, with excellent hemodynamic characteristics, a low transvalvular gradient and a large effective orifice area.

Emboli and Neuropsychological Outcome Following Cardiopulmonary Bypass.

The dramatic decline in mortality related to cardiac surgery has resulted in over 330,000 surgeries involving cardiopulmonary bypass (CPB) being performed yearly in the United States. Although few patients die as a result of cardiac surgery, over two thirds of the patients demonstrate evidence of acute neuropsychological dysfunction postoperatively. The potential mechanisms contributing to post-CPB neuropsychological deficits are many, but two major inter-related etiologic factors, hypo-perfusion and emboli, are suggested as the probable culprits. If embolism is the cause of the deficits, increasing cerebral perfusion would deliver more emboli and increase the amount and severity of injury. Conversely, if hypoperfusion is the cause of the injury, then decreasing brain blood flow to minimize embolic delivery would increase the likelihood of perfusion injury. By monitoring the carotid arteries of patients undergoing coronary artery bypass graft surgery, we have determined the frequency and quantity of embolic signals that occur during CPB. Although we have not been able to determine the nature of the embolus, gaseous or solid, we have demonstrated a relationship between the overall embolic load and the probability of having NP dysfunction. (ECHOCARDIOGRAPHY, Volume 13, September 1996)

Risk factors for cardiac surgery: the high-risk patient.

The demographics of cardiac surgical patients are changing. The average age at operation has risen 10 years since 1980, and the risk of surgery related to severe atherosclerosis of the aorta and its branches is increasing. Although cardiac risk is increasing, operative techniques to minimize cardiac risk have placed the emphasis on comorbid conditions. Patients with preexisting unstable cerebral, vascular, renal, and hepatic disease are at a markedly increased risk and should be carefully evaluated preoperatively.