Scoring systems in the prediction of atrial fibrillation recurrence after surgical ablation.

INTRODUCTION: More than every third patient experiences recurrent atrial fibrillation after surgical pulmonary vein ablation. However, it remains challenging to predict who will and who will not experience this event. Scoring systems containing baseline risk factors have been proposed as a complementary tool to identify patients at higher risk of experiencing atrial fibrillation recurrence. Therefore, the aim of this study was to assess the value of the scoring systems APPLE, CHA2 DS2 -VASc, and CHADS2 in predicting atrial fibrillation recurrence following surgical ablation. METHODS: In a retrospective study, we identified all patients undergoing concomitant pulmonary vein ablation during cardiac surgery. APPLE-, CHA2 DS2 -VASc-, and CHADS2 scores were calculated for each patient. Subsequently, the predictive value of the scoring systems on atrial fibrillation recurrence 3-12 months postablation was assessed using receiver operating characteristic curves and logistic regression analyses. RESULTS: Receiver operating characteristic curves showed the superiority of the APPLE scoring system with an area under the curve of 0.690 compared to 0.571 for CHA2 DS2 -VASc and 0.569 for CHADS2 , p = .01. Using logistic regression analyses, APPLE and CHA2 DS2 -VASc were predictors of atrial fibrillation recurrence between 3- and 12 months after surgical ablation (odds ratio [OR] 1.93, 95% confidence interval [CI] 1.39-2.67, p < .01 and OR 1.17, 95% CI 1.01-1.36, p = .04, respectively). CONCLUSIONS: The APPLE scoring system is superior to CHA2 DS2 -VASc and CHADS2 in predicting atrial fibrillation recurrence after surgical ablation. It can be used as a complementary tool to select the right candidates for surgical ablation and identify patients who need more frequent clinical and electrocardiogram controls.

Epidural analgesia and abnormal coagulation in patients undergoing minimal invasive repair of pectus excavatum.

Background: Epidural analgesia (EA) is effective in patients undergoing minimal invasive repair of pectus excavatum (MIRPE) but is associated with major complications such as epidural hematomas. It is recommended to assess coagulation status in patients receiving anticoagulant therapy prior to EA, although no consensus exists in patients without a history of bleeding tendency or anticoagulant therapy. Thus, the aim of this paper was to assess 1) the prevalence of abnormal routine coagulation parameters, i.e., international normalized ratio (INR) and platelet count, and 2) the safety of EA in patients undergoing MIRPE. Methods: In this retrospective study, we identified 1,973 patients undergoing MIRPE at our center between 2001 and 2019. Complications related to EA were registered for all patients. Information on coagulation parameters was present in 929 patients. Patients with spontaneously elevated INR ≥1.5 were referred for assessment of coagulation factor VII in order to assess the cause of the elevated INR. Results: Of 929 patients with coagulation information available, 18 patients had spontaneously elevated INR ≥1.5 (1.9%). In patients with INR ≥1.5, 12 patients underwent further assessment of factor VII, with all patients having a slightly reduced factor VII close to the lower reference range. The majority of the 1,973 patients undergoing MIRPE received EA (99.6%) with very low complication rates (0.2%) and no incidence of epidural hematomas. Conclusion: In patients undergoing MIRPE, coagulation screening prior to EA should not be mandatory as it revealed no clinically relevant consequences. EA is safe with very low complication rates.

Discontinuation of anticoagulants after successful surgical ablation of atrial fibrillation.

BACKGROUND: The decision of whether to continue oral anticoagulation therapy (OAT) after successful surgical ablation of atrial fibrillation is challenging, and current guidelines provide no specific recommendations on whether or not it is safe to terminate OAT. Therefore, the aim of this study was to assess long-term outcomes in patients who either did or did not, receive OAT after surgical ablation of atrial fibrillation. METHODS: In a prospective follow-up study, patients were included if surgical ablation of atrial fibrillation concomitantly with other cardiac surgery was done, between 2004 and 2018 at Aarhus University Hospital, Denmark. After 12 months, OAT was discontinued if: (a) sinus rhythm was documented by electrocardiogram, (b) atrial fibrillation was absent on 5-day Holter monitoring, (c) CHADS2 score ≤2, and (d) no other indications for OAT were present. Follow-up was ended in April 2019. RESULTS: A total of 560 patients underwent surgical ablation of which 436 patients reached the baseline at 12 months; 286 patients received OAT, and 150 had OAT discontinued. Survival analysis revealed no differences between the two groups (P = .723). Mean survival time in the group receiving OAT was 5.3 ± 3.3 years, compared to 5.1 ± 3.0 years in the group where OAT was discontinued (P = .784). There was no difference in major adverse cardiac and cerebrovascular events between the two groups (P = .846). CONCLUSION: Discontinuation of OAT is safe in patients with a CHADS2 score ≤2 following successful surgical ablation and left atrial appendage occlusion. This conclusion needs to be confirmed in randomized trials.

Mediastino-hepato-renal cystic lymphangiomas-diagnostic and surgical considerations.

Cystic lymphangiomas or hygromas are rare benign vascular tumours, caused by congenital malformation of the lymphatic vessels. It appears as a progressive swelling in the head or neck of children during 2-5 years of life, yet rarely seen in the mediastinum or abdomen. Symptomatic mediastinal cystic lymphangiomas provide symptoms such as chest pain, breathlessness, cough, and dysphagia, making it difficult to differentiate from other mediastinal tumours. The tumour can become larger due to infections, inflammations, obstructions and bleedings. Chest X-ray, ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI) provide helpful information but the diagnosis appears merely after surgical resection and histological examination. Only a few cases have been reported. Hence, we report the first case of a mediastinal and asymptomatic renal and multiple hepatic cystic lymphangiomas in a 71-year-old male with respiratory symptoms and sever reduction in lung capacity. The symptoms regressed fully after surgical excision and lung diffusions capacity increased significantly.

Bilateral pneumothoraces in a patient with laryngeal carcinoma following tracheostomy for stridor.

A pneumothorax following a tracheostomy is a known but rare complication. Bilateral pneumothoraces are rarer still and very few are described in the literature. We present a case of bilateral pneumothoraces following an emergency tracheostomy in a female patient with known laryngeal carcinoma. She was managed with bilateral intercostal chest drains (ICDs) with good result. Anatomical integrity of the oesophagus was confirmed using barium swallow. Prior to removal of the drains a CT scan of the thorax was performed that showed disease progression and led to a change in the initial curative plan. We emphasise the importance in early diagnosis of this complication with a low index of suspicion. We suggest regular monitoring and a low threshold for treatment with bilateral ICDs.

Amiodarone is a cost-neutral way of preventing atrial fibrillation after surgery for lung cancer.

OBJECTIVES: Our aim was to estimate the costs and health benefits of routinely administered postoperative amiodarone as a prophylactic agent in reducing the risk of atrial fibrillation in patients undergoing surgery for lung cancer. METHODS: This was a cost-effectiveness study, based on the randomized, controlled, double-blinded PASCART study, using avoidance of atrial fibrillation as the measure of benefit. Two hundred and fifty-four eligible, consecutively enrolled patients, undergoing surgery for lung cancer at the department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Denmark, were included and randomized to receive either 300 mg of amiodarone or placebo (5% aqueous dextrose solution), administered intravenously over 20 min immediately after surgery, followed by 600 mg of amiodarone/placebo orally twice per day (8 a.m. and 6 p.m.) for the first five postoperative days. RESULTS: In the amiodarone group there were 11 cases of atrial fibrillation, compared with 38 in the control group (P < 0.001). There were no differences in the length of hospital stay or resources used. The mean total costs per patient were equal and amounted to €7288 per patient (P = 0.23). There were no signs of adverse developments referable to amiodarone in this prophylactic regime. CONCLUSIONS: For patients undergoing surgery for lung cancer, routine use of postoperative prophylactic intravenous bolus and five subsequent days of oral amiodarone therapy reduces the risk of atrial fibrillation in a cost-neutral manner.

Venous thromboembolism in patients undergoing operations for lung cancer: a systematic review.

BACKGROUND: The risk of venous thromboembolism is perceived to be high in patients with lung cancer. However, existing studies in patients undergoing operations for lung cancer draw inconsistent conclusions and recommendations in terms of thromboprophylaxis. The aim of this study was to perform a systematic review of the risk of perioperative and postoperative venous thromboembolism for patients undergoing potential curative surgical procedures for primary lung cancer METHODS: This was a systematic review including studies of patients with primary lung cancer undergoing operations with curative intent. RESULTS: We included 19 studies with a total of 10,660 patients. All studies, except 1, were observational in design. Marked heterogeneity was found between the studies in terms of methodologic aspects, patient characteristics, and findings. The mean risk of venous thromboembolism (VTE) was estimated at 2.0% (range, 0.2%-19%), with a mean observation period of 16 months (range, 0.1-22), and the risk was nearly identical in studies with 1 month of follow-up and studies with a longer follow-up. CONCLUSIONS: The evidence for using thromboprophylaxis after lung cancer operations is relatively sparse, and the use is based predominantly on clinical consensus. However, the risk of VTE seems to occur predominantly within the initial postoperative period, and subsequently the risk falls. Future research should focus on identifying patients and surgical procedures that increase the risk of VTE. This could be accomplished by large observational studies in addition to randomized controlled trials evaluating different thromboprophylaxis strategies.

Amiodarone significantly decreases atrial fibrillation in patients undergoing surgery for lung cancer.

BACKGROUND: Postoperative atrial fibrillation occurs in 5% to 65% of patients undergoing thoracic surgery. Although postoperative atrial fibrillation often is regarded as a temporary, benign, operation-related problem, it is associated with a twofold to threefold increase in risk of adverse events, including transient or permanent stroke, acute myocardial infarction, and death. METHODS: A total of 254 consecutively eligible enrolled patients undergoing surgery for lung cancer were included in this randomized, controlled, double-blinded trial. Patients received 300 mg of amiodarone or placebo intravenously over 20 minutes immediately after surgery and an oral dose of 600 mg of amiodarone or placebo twice daily during the first 5 postoperative days. RESULTS: The patients in the amiodarone prophylaxis group had a reduction in the risk of atrial fibrillation of 23% (12 to 31); number needed to treat was 4.4 (3.1 to 7.8). A total of 38 in the control group and 11 in the amiodarone group experienced atrial fibrillation (p<0.001). Adverse effects were observed in 10 patients equally distributed in both trial arms. CONCLUSIONS: Postoperative prophylaxis with a high dose of oral amiodarone after an intravenous bolus infusion is a safe, practical, feasible, and effective regimen for patients with lung cancer undergoing surgery. It significantly reduced the incidence of postoperative atrial fibrillation.

Congenital heart defects and developmental and other psychiatric disorders: a Danish nationwide cohort study.

BACKGROUND: We examined the risk of psychiatric in-patient admissions and out-patient visits among Danish patients with congenital heart defects (CHD). METHODS AND RESULTS: Using the Danish National Registry of Patients, we identified CHD patients born January 1, 1977, to January 1, 2002. For each patient, we randomly selected 10 population-comparison cohort members from the Danish Civil Registration System, matched by sex and birth year. We computed cumulative risk and hazard ratios (HRs) of time to first psychiatric in-patient admission or out-patient visit identified in the Danish Psychiatric Central Registry and adjusted for parents' educational level and parents' psychiatric morbidity. We identified 6927 CHD patients. At 15 years of age, the cumulative risk of psychiatric admissions or out-patient visits was 5.9% (95% confidence interval [CI], 5.2%-6.6%) among CHD patients. The HRs for CHD patients and comparison cohort members aged 0 to 14 years were 1.8 (95% CI: 1.5-2.1) for males and 2.5 (95% CI: 2.0-3.1) for females. For patients aged 15 to 30 years, the HRs were 1.6 (95% CI: 1.2-2.0) for males and 1.0 (95% CI: 0.8-1.3) for females. Congenital heart defect patients, both with and without invasive therapeutic interventions or extracardiac defects or syndromes, had a higher risk of psychiatric in-patient admissions or out-patient visits than comparison cohort members. After restriction of the comparison cohort to patients with diabetes mellitus or asthma (n=2554), the HR was 1.41 (95% CI: 1.07-1.85) for patients aged 0 to 14 years and 0.70 (95% CI: 0.52-0.94) for patients aged 15 to 30 years. CONCLUSION: Congenital heart disease patients with or without invasive therapeutic interventions are at increased risk of developmental and other psychiatric disorders, which seem to develop earlier than in patients with diabetes mellitus or asthma.

Educational achievement among long-term survivors of congenital heart defects: a Danish population-based follow-up study.

BACKGROUND: Congenital heart defect patients may experience neurodevelopmental impairment. We investigated their educational attainments from basic schooling to higher education. PATIENTS AND METHODS: Using administrative databases, we identified all Danish patients with a cardiac defect diagnosis born from 1 January, 1977 to 1 January, 1991 and alive at age 13 years. As a comparison cohort, we randomly sampled 10 persons per patient. We obtained information on educational attainment from Denmark's Database for Labour Market Research. The study population was followed until achievement of educational levels, death, emigration, or 1 January, 2006. We estimated the hazard ratio of attaining given educational levels, conditional on completing preceding levels, using discrete-time Cox regression and adjusting for socio-economic factors. Analyses were repeated for a sub-cohort of patients and controls born at term and without extracardiac defects or chromosomal anomalies. RESULTS: We identified 2986 patients. Their probability of completing compulsory basic schooling was approximately 10% lower than that of control individuals (adjusted hazard ratio = 0.79, ranged from 0.75 to 0.82 0.79; 95% confidence interval: 0.75-0.82). Their subsequent probability of completing secondary school was lower than that of the controls, both for all patients (adjusted hazard ratio = 0.74; 95% confidence interval: 0.69-0.80) and for the sub-cohort (adjusted hazard ratio = 0.80; 95% confidence interval: 0.73-0.86). The probability of attaining a higher degree, conditional on completion of youth education, was affected both for all patients (adjusted hazard ratio = 0.88; 95% confidence interval: 0.76-1.01) and for the sub-cohort (adjusted hazard ratio = 0.92; 95% confidence interval: 0.79-1.07). CONCLUSION: The probability of educational attainment was reduced among long-term congenital heart defect survivors.

Insulin resistance, adiponectin and adverse outcomes following elective cardiac surgery: a prospective follow-up study.

BACKGROUND: Insulin resistance and adiponectin are markers of cardio-metabolic disease and associated with adverse cardiovascular outcomes. The present study examined whether preoperative insulin resistance or adiponectin were associated with short- and long-term adverse outcomes in non-diabetic patients undergoing elective cardiac surgery. METHODS: In a prospective study, we assessed insulin resistance and adiponectin levels from preoperative fasting blood samples in 836 patients undergoing cardiac surgery. Population-based medical registries were used for postoperative follow-up. Outcomes included all-cause death, myocardial infarction or percutaneous coronary intervention, stroke, re-exploration, renal failure, and infections. The ability of insulin resistance and adiponectin to predict clinical adverse outcomes was examined using receiver operating characteristics. RESULTS: Neither insulin resistance nor adiponectin were statistically significantly associated with 30-day mortality, but adiponectin was associated with an increased 31-365-day mortality (adjusted odds ratio 2.9 [95% confidence interval 1.3-6.4]) comparing the upper quartile with the three lower quartiles. Insulin resistance was a poor predictor of adverse outcomes. In contrast, the predictive accuracy of adiponectin (area under curve 0.75 [95% confidence interval 0.65-0.85]) was similar to that of the EuroSCORE (area under curve 0.75 [95% confidence interval 0.67-0.83]) and a model including adiponectin and the EuroSCORE had an area under curve of 0.78 [95% confidence interval 0.68-0.88] concerning 31-365-day mortality. CONCLUSIONS: Elevated adiponectin levels, but not insulin resistance, were associated with increased mortality and appear to be a strong predictor of long-term mortality. Additional studies are warranted to further clarify the possible clinical role of adiponectin assessment in cardiac surgery. TRIAL REGISTRATION: The Danish Data Protection Agency; reference no. 2007-41-1514.

[Coarctation of the aorta: 40-year follow-up after surgical repair--secondary publication]. / Coarctatio aortae: 40 års opfølgning efter kirurgisk korrektion - sekundaerpublikation.

Coarctation of the aorta (CoA) was previously considered cured after surgical repair. Among 229 patients operated for CoA in Aarhus between 1965 and 1985, 14 died at surgery and 35 died during 20-40 years of follow-up, mainly due to cardiovascular disease. The mortality among CoA patients was 4.3 times higher than in a control population. Among 178 survivors, 35 had been reoperated and another 11 had received medical treatment for heart disease. Antihypertensive drugs were used by 25% of the survivors. Thus, CoA is not cured by surgery and long term follow-up is necessary.

Thrombin generation and coagulation factor activities: evaluation and comparison with the international normalized ratio.

Oral anticoagulation therapy is monitored effectively by the international normalized ratio (INR). However, INR is perhaps not optimal in predicting risk of complications. Other more sensitive methods have been suggested. The aims of this study were to estimate the variability and association of calibrated automated thrombin generation (CAT) and clotting activity of coagulation factors II, VII, IX and X and to compare these parameters with the INR measured in a central laboratory as well as using portable coagulometers. Twenty-four patients on stable oral anticoagulation therapy with coumarins were followed prospectively for 6 weeks. A mixed effect model was used for the statistical analyses. The CAT and activity of coagulation factors II, VII, IX and X showed no significant difference in variability over time. Approximately 50% of the total variability of the CAT and coagulation factor activities was displayed as variation in the INR. The remaining variability was displayed as 'within patient variation'. The CAT and coagulation factor activities were significantly associated with the INR. In conclusion, neither CAT nor coagulation factor activities seem to provide additional information about the biological variation; however, larger clinical studies are needed to investigate the ability to predict complications in individual patients on oral anticoagulation therapy.

International normalised ratio (INR) measured on the CoaguChek S and XS compared with the laboratory for determination of precision and accuracy.

Oral anticoagulation therapy is monitored by the use of international normalised ratio (INR). Patients performing self-management estimate INR using a coagulometer, but studies have been partly flawed regarding the estimated precision and accuracy. The objective was to estimate the imprecision and accuracy for two different coagulometers (CoaguChek S and XS). Twenty-four patients treated with coumarin were prospectively followed for six weeks. INR's were analyzed weekly in duplicates on both coagulometers, and compared with results from the hospital laboratory. Statistical analysis included Bland-Altman plot, 95% limits of agreement, coefficient of variance (CV), and an analysis of variance using a mixed effect model. Comparing 141 duplicate measurements (a total of 564 measurements) of INR, we found that the CoaguChek S and CoaguChek XS had a precision (CV) of 3.4% and 2.3%, respectively. Regarding analytical accuracy, the INR measurements tended to be lower on the coagulometers, and regarding diagnostic accuracy the CoaguChek S and CoaguChek XS deviated more than 15% from the laboratory measurements in 40% and 43% of the measurements, respectively. In conclusion, the precision of the coagulometers was found to be good, but only the CoaguChek XS had a precision within the predefined limit of 3%. Regarding analytical accuracy, the INR measurements tended to be lower on the coagulometers, compared to the laboratory. A large proportion of measurement of the coagulometers deviated more than 15% from the laboratory measurements. Whether this will have a clinical impact awaits further studies.

The effects of surgically induced right bundle branch block on left ventricular function after closure of the ventricular septal defect.

OBJECTIVE: To determine the long-term significance of right bundle branch block on left ventricular systolic and diastolic function in children subsequent to surgical closure of ventricular septal defect. METHODS: We studied 26 children who underwent surgical closure of a ventricular septal defect 11 +/- 2 years postoperatively by use of conventional and tissue Doppler echocardiography, comparing the findings to those obtained from a control group. Of those having surgical correction 14 had postoperative right bundle branch block. RESULTS: Irrespective of the presence of right bundle branch block, the peak systolic velocity of the mitral ring was lower in those undergoing surgical correction, with values of 5.2 +/- 1.4 cm/s in those with right bundle branch block, 5.4 +/- 1.2 cm/s in those without right bundle branch block after surgical correction, and 6.6 +/- 1.0 cm/s in the control subjects (p < 0.01). In terms of diastolic function, the early septal velocity of transmitral inflow divided by the early diastolic mitral annular velocity was significantly higher in children with right bundle branch block, at 12 +/- 3.0 cm/s compared to 8.4 +/- 1.5 cm/s in the control subjects (p < 0.01), but not significantly higher in the children without right bundle branch block after correction compared to the control group. The fractional shortening percentage was similar in both patients and control subjects. The changes noted in left ventricular function were not significantly related to age at surgery, the period of follow-up, or the surgical method. CONCLUSIONS: Systolic long axis function is significantly reduced in children after surgical closure of ventricular septal defects, irrespective of the presence of right bundle branch block. Diastolic dysfunction, in contrast, was observed primarily in children with post-operative right bundle branch block.

Amiodarone protects diabetics and non-diabetics undergoing coronary artery bypass grafting equally.

OBJECTIVE: To evaluate amiodarone prophylaxis in diabetics and non-diabetics. Further to clarify whether the risk of developing atrial fibrillation is higher for diabetics than non-diabetic patients, and to evaluate whether the diabetic status has any influence on the length of in-hospital stay. DESIGN: Subgroup analysis within a randomized, controlled, double-blinded trial. RESULTS: At 30 days of follow-up atrial fibrillation was equally frequent among diabetics (22%) and non-diabetics (17%) (p =0.41). The length of in-hospital stay for diabetics was prolonged with 25% (9%; 45%). The prophylactic amiodarone was found equally efficient in diabetics and non-diabetics, as the relative risk ratios were 1.2 (0.4-5.4) and 2.0 (0.3-12.5), respectively. CONCLUSIONS: Diabetics and non-diabetics had the same effect of the amiodarone prophylaxis regime. Atrial fibrillation developed equally among diabetics and non-diabetics, but the length of stay was prolonged for diabetics.

Caval blood flow during supine exercise in normal and Fontan patients.

BACKGROUND: Extracardiac total cavo-pulmonary connection (TCPC) bypasses the right atrium and has in theory better hemodynamics than intraatrial TCPC repair. Both are thought to have inferior hemodynamics compared with a normal circulation. Direct comparison of flow rates at rest and during exercise with magnetic resonance imaging technique have not been performed. METHODS: The study comprised 20 children. Six children (median age, 9.3 years; interquartile range, 2.2) had undergone extracardiac TCPC. Eight children (median age, 8.9 years; interquartile range, 5.0) had an intraatrial TCPC, and 6 children (median age, 10.3 years; interquartile range, 2.6) were healthy control subjects. Blood flows in the aorta, inferior vena cava, and superior vena cava were measured at rest and during two levels of submaximal supine bicycle exercise (0.5 W/kg and 1.0 W/kg) using a magnetic resonance imaging scanner mounted with a bicycle. RESULTS: Heart rate, respiratory rate, inspiratory fraction, and blood flow rates in the aorta and inferior vena cava increased equally in all three groups. If patients were grouped together, flow rates were significantly lower, and the inspiratory flow fraction in the inferior vena cava was significantly higher, than in control subjects. Retrograde flows were observed in all three groups at rest but tapered off with exercise. CONCLUSIONS: At submaximal levels of lower limb exercise, patients with extracardiac as well as intraatrial TCPC showed a similar increase in respiration, heart rate, and aortic and caval flow rates as healthy control subjects. This is in accordance with the observation that many patients with TCPC perform well during daily life activities.

Amiodarone cost effectiveness in preventing atrial fibrillation after coronary artery bypass graft surgery.

BACKGROUND: The purpose of this study was to estimate the costs and health benefits of routinely administered postoperative amiodarone as prevention of atrial fibrillation for patients undergoing coronary artery bypass grafting (CABG) for stable angina. METHODS: This cost-effectiveness study was based on a randomized, controlled, double-blind trial (the RASCABG study) using avoidance of atrial fibrillation as the measure of benefit at the Department of Cardiothoracic and Vascular Surgery, Aarhus University Hospital, Skejby, Denmark. Two hundred and fifty eligible consecutively enrolled CABG patients were included to receive either 300 mg amiodarone or placebo (5% aqueous dextrose solution) administered intravenously over 20 minutes followed by 600 mg amiodarone/placebo orally twice a day (8 am and 8 pm) for the first 5 postoperative days. RESULTS: In the amiodarone group, there were 14 cases of atrial fibrillation compared with 32 in the control group (p < 0.01) whereas there were no differences in the length of stay. The mean total cost per patient was 7,639 euros in the amiodarone group and 7,814 euros in the placebo group (p < 0.01). CONCLUSIONS: Routine use of postoperative prophylactic intravenous bolus and subsequent 5 days of oral amiodarone therapy after coronary artery bypass grafting reduces the risk of atrial fibrillation and decreases the total costs of care by 175 euros per patient.

Changes in turbulence with rotation of the omnicarbon prosthesis.

This study was performed to determine whether annular plane orientation of the Omnicarbon aortic valve influences forward flow turbulence. The Omnicarbon prostheses was modified to allow in situ manual rotation of the valve when implanted in the aortic position of eight 90 kg pigs. Pulsed Doppler ultrasound was used to acquire velocity measurements at 17 locations within the cross-sectional area of the ascending aorta. In each animal, 12 valve rotations were tested in this manner. Reynolds normal stresses were estimated from the velocity measurements. High Reynolds normal stresses were concentrated between left and posterior-right sides of the aortic wall for all orientations studied. No trends in mean or maximum Reynolds normal stresses with respect to valve rotation were consistent in the experiments. Unlike previous experiments with the Medtronic-Hall tilting disc valve, these experiments showed no notable changes in Reynolds normal stress with respect to orientation of the Omnicarbon valve. This suggests that the tendency of turbulent stresses to change with tilting disc valve orientation may be dependent on valve design.