Recellularization of decellularized mitral heart valves in juvenile pigs.

BACKGROUND AND AIM OF THE STUDY: Glutaraldehyde-preserved bioprosthetic heart valves are non-viable and have a limited durability because of calcification, tissue wear, and inflammation, especially in children. Decellularized porcine heart valves, when treated with deoxycholic acid (DOA), have exhibited complete recellularization and an absence of calcification when implanted into the pulmonary position in juvenile sheep. The study aim was to determine the degree of recellularization and calcification in DOA-treated heart valve prostheses in the mitral position in juvenile pigs. METHODS: A mitral heart valve prosthesis was implanted into each of 17 pigs, and subsequently explanted and fixed in formaldehyde after between five and 26 weeks. A gross pathologic assessment, high-resolution X-ray imaging and histological examination were then performed on each valve. RESULTS: Eight pigs survived the observational period. Five valves had only a slight fibrin deposition and calcification foci within the fibrin deposits. Three valves had severe thrombotic material deposits with disseminated calcification and valve stenosis, and one valve had infective endocarditis. A myofibroblast-like cell ingrowth was observed at different locations of the valve housing in all explanted heart valves, but ingrowth in the basal part of the cusp matrix was limited. In four valve prostheses, endothelial cells covered up to 10% of the cusp surface after six months. Inflammatory cells were observed in large numbers in those valves showing endocarditis and severe thrombosis, but in only limited numbers in the other valves. CONCLUSION: All valves showed the deposition of fibrin and platelet material, in three cases to a severe degree. A limited ingrowth of both endothelial and myofibroblast-like cells was observed in five valves in which calcification was limited to a few commissural foci. The non-endothelialized surface of the decellularized valves makes them very susceptible to platelet and fibrin deposition; however, slow revitalization seems possible.

Early outcome after surgery for active native and prosthetic aortic valve endocarditis.

BACKGROUND AND AIM OF THE STUDY: Today, the in-hospital mortality of patients treated surgically for active aortic native and prosthetic valve endocarditis remains high. The study aim was to identify the preoperative and intraoperative predictors of early outcome. METHODS: Between January 2004 and December 2006, 75 patients (57 males, 18 females; mean age 61.6 +/- 14.1 years) underwent surgery for active native valve (NVE) or prosthetic aortic valve endocarditis (PVE). RESULTS: Active aortic NVE was present in 49 patients (65.3%), and PVE in 26 (34.7%). Staphylococcus species were the most common infecting microorganisms in both groups, while 20 cases (26.7%) were culture-negative. Except for significantly higher preoperative renal failure (RF) in patients with PVE (p = 0.01), the clinical characteristics were equally distributed. Four patient subsets were identified based on the extent of the infectious process: (i) locally controlled NVE (38.7%); (ii) locally uncontrolled NVE (26.7%); (iii) locally controlled PVE (14.6%); and (iv) locally uncontrolled PVE (20%). Aortic valve replacement (AVR) was performed with a stentless bioprosthesis in 53 cases (70.7%), a mechanical prosthesis in eight (10.6%), and a Ross procedure in 14 (18.7%). Concomitant active mitral valve endocarditis was treated in 17 patients (22.7%). Associated procedures were performed in 14 cases (18.7%). The in-hospital mortality was 24% (n = 18). Female gender (p = 0.0147), preoperative septic or cardiogenic shock (p = 0.0275) and previous embolic events (p = 0.0129) were identified as independent predictors for in-hospital mortality. Eight late deaths occurred; the estimated overall actuarial survival was 66.6 +/- 5.6% at 12 months and 60.7 +/- 6.5% at 24 months. On Cox multiple regression, age > 70 years (p = 0.0113), preoperative RF (p = 0.0015) and mitral valve surgery due to concomitant infective endocarditis (p = 0.0363) were significant adverse predictors of late death. CONCLUSION: Surgery for active aortic valve infective endocarditis is associated with high operative mortality and morbidity. Failure of antibiotic therapy causing septic or cardiogenic shock and delayed referral to surgery may have a detrimental effect on early outcome. Surgical eradication of cardiac infections should always be associated with the treatment of extracardiac septic foci, which could maintain a septic state and adversely influence early outcome. Adhesion to surgical guidelines, together with a multidisciplinary approach, may have a major impact on the early prognosis of these high-risk patients.

In-vivo repopularization of a tissue-engineered heart valve in a human subject.

A 63-year-old male with a massively calcified aortic valve showed an active lifestyle. Therefore, valve replacement was completed using the Ross procedure. During postoperative echocardiographic control, a ventricular septal defect was noted which was closed surgically. During this reoperation, a biopsy sample was taken from the wall of the tissue-engineered heart valve which was used to reconstruct the right ventricular outflow tract. A persistent monolayer of endothelial cells and host recellularization of the deeper layer was demonstrated histologically. The postoperative course was uneventful, and the patient rapidly recovered. After six years, he remains in excellent health.

The impact of an hematocrit of 20% during normothermic cardiopulmonary bypass for elective low risk coronary artery bypass graft surgery on oxygen delivery and clinical outcome--a randomized controlled study [ISRCTN35655335].

INTRODUCTION: Cardiopulmonary bypass (CPB) induces hemodilutional anemia, which frequently requires the transfusion of blood products. The objective of this study was to evaluate oxygen delivery and consumption and clinical outcome in low risk patients who were allocated to an hematocrit (Hct) of 20% versus 25% during normothermic CPB for elective coronary artery bypass graft (CABG) surgery. METHODS: This study was a prospective, randomized and controlled trial. Patients were subjected to normothermic CPB (35 to 36 degrees C) and were observed until discharge from the intensive care unit (ICU). Outcome measures were calculated whole body oxygen delivery, oxygen consumption and clinical outcome. A nonparametric multivariate analysis of variance for repeated measurements and small sample sizes was performed. RESULTS: In a total of 54 patients (25% Hct, n = 28; 20% Hct, n = 26), calculated oxygen delivery (p = 0.11), oxygen consumption (p = 0.06) and blood lactate (p = 0.60) were not significantly different between groups. Clinical outcomes were not different between groups. CONCLUSION: These data indicate that an Hct of 20% during normothermic CPB maintained calculated whole body oxygen delivery above a critical level after elective CABG surgery in low risk patients. The question of whether a transfusion trigger in excess of 20% Hct during normothermic CPB is still supported requires a larger prospective and randomized trial.

Increased interleukin-6 after cardiac surgery predicts infection.

Early diagnosis and treatment of infection after cardiac surgery with cardiopulmonary bypass (CPB) improves outcome. Conventional laboratory tests, such as C-reactive protein and white blood cell count can not distinguish patients with early infection from those with systemic inflammatory response syndrome but without infection. After CPB, there is a systemic release of proinflammatory and antiinflammatory cytokines, including tumor necrosis factor-alpha, interleukin (IL)-6, and IL-10. We investigated the predictive ability of these variables for infection after cardiac surgery. Forty-six patients with impaired left ventricular ejection fraction (<60%), scheduled for cardiac surgery, were included. Plasma samples were drawn 1 day before and immediately before surgery, on admission to the intensive care unit, and on days 1, 3, and 7 after surgery. Infection was identified according to the criteria of the Centers for Disease Control and Prevention. After surgery 13 patients developed an infection. In patients with infection, confirmed a median of 4 days after surgery, all measurements of IL-6, and IL-10 on postoperative day 3 were significantly increased. Tumor necrosis factor-alpha, leukocytes, and C-reactive protein were not increased in these patients. Immediately after surgery blood glucose was significantly increased in patients with infection. Increased IL-6 after CPB is predictive of infection after cardiac surgery in patients with impaired left ventricular function.

Heparin-induced thrombocytopenia type II in an infant with a congenital heart defect--anticoagulation during cardiopulmonary bypass with epoprostenol sodium and heparin.

BACKGROUND: Heparin-induced thrombocytopenia type II (HIT II) is a rare but potentially life-threatening complication of heparin therapy. Hitherto, only few reports on HIT II in infants and children have been published. In particular, infants and children who have to be operated under cardiopulmonary bypass are at risk as an alternative anticoagulation is required. CASE PRESENTATION: We report on an infant with a congenital heart defect who was scheduled for cardiac surgery (Damus Kaye-Stansel procedure) with cardiopulmonary bypass. In the intensive care unit, an HIT II was diagnosed. Before surgery, the infant was pretreated with epoprostenol sodium (incrementally increasing up to a maximum dose of 30 ng/kg/min) before heparin was administered shortly after sternotomy. Mean arterial pressure was kept stable with an infusion of norepinephrine and the course of the cardiopulmonary bypass showed no signs of thrombosis. Drainage loss in the postoperative period was moderate. CONCLUSION: In HIT II infants, pretreatment with epoprostenol sodium before reexposure to heparin may offer a safe and effective anticoagulation for cardiopulmonary bypass.

Pulse contour analysis after normothermic cardiopulmonary bypass in cardiac surgery patients.

INTRODUCTION: Monitoring of the cardiac output by continuous arterial pulse contour (COPiCCOpulse) analysis is a clinically validated procedure proved to be an alternative to the pulmonary artery catheter thermodilution cardiac output (COPACtherm) in cardiac surgical patients. There is ongoing debate, however, of whether the COPiCCOpulse is accurate after profound hemodynamic changes. The aim of this study was therefore to compare the COPiCCOpulse after cardiopulmonary bypass (CPB) with a simultaneous measurement of the COPACtherm. METHODS: After ethical approval and written informed consent, data of 45 patients were analyzed during this prospective study. During coronary artery bypass graft surgery, the aortic transpulmonary thermodilution cardiac output (COPiCCOtherm) and the COPACtherm were determined in all patients. Prior to surgery, the COPiCCOpulse was calibrated by triple transpulmonary thermodilution measurement of the COPiCCOtherm. After termination of CPB, the COPiCCOpulse was documented. Both COPACtherm and COPiCCOtherm were also simultaneously determined and documented. RESULTS: Regression analysis between COPACtherm and COPiCCOtherm prior to CPB showed a correlation coefficient of 0.95 (P < 0.001), and after CPB showed a correlation coefficient of 0.82 (P < 0.001). Bland-Altman analysis showed a mean bias and limits of agreement of 0.0 l/minute and -1.4 to +1.4 l/minute prior to CPB and of 0.3 l/minute and -1.9 to +2.5 l/minute after CPB, respectively. Regression analysis of COPiCCOpulse versus COPiCCOtherm and of COPiCCOpulse versus COPACtherm after CPB showed a correlation coefficient of 0.67 (P < 0.001) and 0.63 (P < 0.001), respectively. Bland-Altman analysis showed a mean bias and limits of agreement of -1.1 l/minute and -1.9 to +4.1 l/minute versus -1.4 l/minute and -4.8 to +2.0 l/minute, respectively. CONCLUSION: We observed an excellent correlation of COPiCCOtherm and COPACtherm measurement prior to CPB. Pulse contour analysis did not yield reliable results with acceptable accuracy and limits of agreement under difficult conditions after weaning from CPB in cardiac surgical patients. The pulse contour analysis thus should be re-calibrated as soon as possible, to prevent false therapeutic consequences.

Aortic valve replacement with new-generation stentless pericardial valves: short-term clinical and hemodynamic results.

BACKGROUND AND AIM OF THE STUDY: Aortic valve replacement (AVR) with stentless bioprostheses offers superior hemodynamics. In order to overcome the disadvantages of older, stentless valves, a new generation of pericardial stentless prostheses has been developed. Herein, the hemodynamic and clinical results of these substitutes have been evaluated. METHODS: Between March 2002 and May 2004, 85 patients (59 females, 26 males; mean age 73.6 +/- 6.1 years) who underwent AVR received either a bovine (Sorin Pericarbon Freedom; SPF; n = 50) or an equine (3F Aortic Bioprosthesis; 3F; n = 35) pericardial stentless valve. Patients were followed up prospectively at six months after surgery by clinical and echocardiographic examination. The mean follow up period was 5.6 +/- 0.8 months, and was 96.4% complete. RESULTS: Mortality was 2.4% at 30 days (two SPF patients; one died at reoperation for suspected valve thrombosis and one was a non-valve-related death) and 2.5% at follow up (two SPF patients; both nonvalve-related). Neither structural valve failure nor endocarditis were observed. Preoperatively, there were no differences in baseline data, functional status and hemodynamics between SPF and 3F patients. The aortic cross-clamp time was similar in both groups (51.7 +/- 11.2 min for SPF; 51.6 +/- 8.2 min for 3F). NYHA functional status improvement was similar in each group (1.8 +/- 0.5 for SPF; 1.7 +/- 0.6 for 3F). The mean transaortic pressure gradient (deltapmean) was reduced in all patients during follow up. With SPF, a lower deltapmean was found for smaller aortic roots (indexed annular diameter (IAD) < 14 mm/m2) as well as in larger (IAD > 14 mm/m2) aortic roots: 8.0 +/- 4.5 mmHg versus 13.2 +/- 7.2 mmHg (p < 0.05) and 6.8 +/- 3.0 mmHg versus 12.8 +/- 4.8 mmHg (p < 0.05), respectively. CONCLUSION: New-generation pericardial stentless aortic valves are very pliable, which facilitates their implantation. Clinical and hemodynamic results with these prostheses are promising. The SPF prosthesis demonstrates excellent performance, and may be superior when implanted in small aortic roots.

Global surgical experience with the Acorn cardiac support device.

OBJECTIVE: Surgical intervention is an option for treating the remodeled and dilated left ventricles of patients with heart failure. Providing end-diastolic support with an innovative mesh-like cardiac support device reduces mechanical stress, improves function, and reverses cardiac remodeling in animal models without safety issues. The objective of this study was to review the global clinical safety and feasibility experience of this device. METHODS: The Acorn CorCap cardiac support device (Acorn Cardiovascular, Inc, St Paul, Minn) has been implanted worldwide in more than 130 patients with dilated cardiomyopathy with or without concomitant cardiac surgery. The device is positioned around the ventricles and given a custom fit. A series of 48 patients were implanted with the device in initial safety and feasibility studies, of whom 33 also received concomitant cardiac surgery. RESULTS: At implantation, 11 patients were in New York Heart Association class II, 33 were in class III, and 4 were in class IV. The average CorCap implantation time was 27 minutes. The mean intraoperative reduction in left ventricular end-diastolic dimension was 4.6% +/- 1%. There were no device-related intraoperative complications. Eight early and 9 late deaths occurred during follow-up extending to 24 months. Actuarial survival was 73% at 12 months and 68% at 24 months. There were no device-related adverse events or evidence of constrictive disease, and coronary artery flow reserve was maintained. Ventricular chamber dimensions decreased, whereas ejection fraction and New York Heart Association class were improved in patients overall and in those patients implanted with the CorCap device without concomitant operations. CONCLUSIONS: The CorCap device appears safe for patients with dilated cardiomyopathy. Randomized clinical trials are underway in Europe, Australia, and North America.

Effects of passive cardiac containment on left ventricular structure and function: verification by volume and flow measurements.

BACKGROUND: The cardiac support device (CSD, Acorn) is a compliant, textile-mesh graft placed around the ventricles to prevent further dilatation and to improve function in congestive heart failure. The aim of this study was to verify post-operative changes in left ventricular volumes, ejection fraction, blood flow, and myocardial mass. METHODS: Fourteen patients underwent contrast-enhanced, electrocardiography-triggered electron-beam computerized tomography before and 6 to 9 months after CSD implantation. We measured volume and flow using the slice-summation method and the indicator-dilution technique. RESULTS: We found significant changes for the following parameters: end-diastolic volume decreased from 382.9 +/- 140.2 ml to 311.3 +/- 138.7 ml, end-systolic volume from 310.4 +/- 132.4 ml to 237.4 +/- 133.8 ml, end-diastolic diameter from 75.3 +/- 7.8 mm to 70.7 +/- 11.6 mm, end-systolic diameter from 65.8 +/- 7.8 mm to 60.0 +/- 14.0 mm, and myocardial mass from 298.6 +/- 79.6 g to 263.1 +/- 76.8 g. Ejection fraction increased from 20.3% +/- 6.4% to 27.8% +/- 13.1%. We found no significant differences for stroke volume (from 72.5 +/- 24.6 ml to 73.8 +/- 23.6 ml), heart rate (from 80.5 +/- 11.0 beats per minute to 76.5 +/- 6.8 beats per minute), and total cardiac output (from 5.8 +/- 1.9 liter/min to 5.6 +/- 1.8 liter/min). Mitral regurgitation fraction decreased from 30.5% +/- 15.5% to 15.6% +/- 12.8%, increasing antegrade cardiac output from 3.8 +/- 0.9 liter/min to 4.7+/-1.5 liter/min. For most parameters, pre- and post-operative values in these patients differed significantly from those in an age- and gender-matched control group. In each patient, we observed a small hyperdense stripe along the pericardium after surgery, but we observed no local complications. CONCLUSION: Three-dimensional structural and functional data obtained by computerized tomography volume and flow measurements confirm the safety and efficacy of CSD implantation.

Ross operation with a tissue-engineered heart valve.

BACKGROUND: The Ross procedure has gained increasing acceptance due to excellent hemodynamic results by replacing the diseased aortic valve with the viable autologous pulmonary valve. Consequently, the right ventricular outflow tract (RVOT) has to be reconstructed. In this report a viable heart valve was created from decellularized cryopreserved pulmonary allograft that was seeded with viable autologous vascular endothelial cells (AVEC). METHODS: A 43-year-old patient suffering from aortic valve stenosis underwent a Ross operation on May 20, 2000, using a tissue engineered (TE) pulmonary allograft to reconstruct the RVOT. Four weeks before the operation a piece of forearm vein was harvested to separate, culture, and characterize AVEC. Follow-up was completed at discharge, 3, 6, and 12 months postoperatively by clinical evaluation, transthoracic echocardiography (TTE), and magnetic resonance imaging (MRI). Additionally, at 1-year follow-up a multislice computed tomographic scan was performed. RESULTS: After four weeks of culturing 8.34 x 10(6) AVEC were available to seed a 27-mm decellularized pulmonary allograft. Trypan blue staining confirmed 96.0% viability. Reendothelialization rate after seeding was 9.0 x 10(5) cells/cm2. TTE and MRI revealed excellent hemodynamic function of the TE heart valve and the neoaortic valve as well. Multislice computed tomography revealed no evidence of valvular calcification. CONCLUSIONS: After 1 year of follow-up the patient is in excellent condition without limitation and exhibits normal aortic and pulmonary valve function.

Reducing the incidence and severity of pericardial adhesions with a sprayable polymeric matrix.

PURPOSE: This study was undertaken to evaluate the antiadhesive properties of a polymeric agent in infants undergoing staged surgical correction of congenital heart abnormalities. DESCRIPTION: Sixteen infants having staged surgical repair were treated with a polymeric matrix at the completion of the initial surgery. There were 5 untreated controls. The tenacity and extent of adhesions at five separate regions of the heart were evaluated at the follow-up surgery. EVALUATION: For all sites combined, there was a threefold difference in median tenacity scores in favor of the experimental treatment (1.0 vs 3.0, p < 0.01). Significant differences were achieved separately at the right ventricle and the anterior surface of the great vessels (p = 0.02 for both comparisons). Analysis of adhesion scores reflecting the extent of adhesions similarly favored the experimental treatment for all sites (80 vs 270, p < 0.01), with significant differences persisting at the right atrium (p < 0.01) and the anterior surface of the great vessels (p = 0.04). There were no treatment-related adverse events. CONCLUSIONS: Use of this polymeric agent at the completion of open cardiac surgery may prevent the occurrence or reduce the severity of pericardial adhesions.

Recombinant factor VIIa after aortic valve replacement in a patient with osteogenesis imperfecta.

A 26-year-old man with osteogenesis imperfecta and severe aortic regurgitation was scheduled for aortic valve replacement. As previously described by other authors the operation was difficult owing to the friability and weakness of the tissues. Mean blood losses of 153 mL per hour during the first 7 postoperative hours were observed. Despite normal coagulation indicators the bleeding did not stop and recombinant factor VIIa was applied at 40 microg/kg. Bleeding was successfully stopped after this single application.

Reverse remodeling of the failing ventricle: surgical intervention with the Acorn Cardiac Support Device.

Preclincial studies have shown that an innovative meshlike cardiac support device (CorCap, Acorn Cardiovascular, Inc., St. Paul, MN) can provide end diastolic support to reduce mechanical stress, improve function, and reverse cardiac remodeling. The CorCap device has been implanted worldwide in more than 130 patients with dilated cardiomyopathy (idiopathic or ischemic), with or without concomitant cardiac surgery. A series of 48 patients was implanted in initial safety and feasibility studies (33 received concomitant cardiac surgery, 15 patients received the CorCap device only). At implant, 33 patients were in New York Heart Association functional class III, 11 in class II, and four in class IV. There were no device-related intraoperative complications, deaths, or adverse events. Eight early and nine late deaths occurred during follow-up extending to 18-24 months. During follow-up, chamber dimensions decreased, and ejection fraction and New York Heart Association functional class improved. The CorCap device is correlated with improvements in patient functional status. Randomized clinical trials are underway in Europe, Australia, and North America.

Passive external cardiac constraint improves segmental left ventricular wall motion and reduces akinetic area in patients with non-ischemic dilated cardiomyopathy.

OBJECTIVE: To verify changes in left ventricular (LV) volumes and regional myocardial wall motion after implantation of a textile cardiac support device (CSD) for passive external constraint in non-ischemic dilated cardiomyopathy. METHODS: In nine male patients participating in a non-randomized clinical trial LV volumes were determined and the segmental LV wall motion was studied by contrast-enhanced electron-beam CT in a sectionwise manner at three ventricular levels (base, middle and apex of ventricle) before and 32+/-6 months after CSD implantation. In 16 myocardial segments ejection fraction and wall thickening were measured semiautomatically after drawing the myocardial contours. The wall motion score index was calculated based on semiquantitative visual grading in each segment. RESULTS: The global LV volumes decreased significantly from 304.3 +/- 90.9 to 231.5 +/- 103.9 ml at end-diastole and from 239.7 +/- 83.7 to 164.0 +/- 97.7 at end-systole (P<0.05). Overall ejection fraction increased from 14.8 +/- 8.2 to 25.7 +/- 17.1% (P<0.05). A segment-by-segment analysis demonstrated a significant increase of regional ejection fraction in the basal myocardium as well as in the mid-inferior, mid-inferolateral, and mid-anterolateral myocardium. Overall wall thickening increased from 16.4 +/- 13.3 to 24.2 +/- 18.1% (P<0.05), but without significant differences in a segment-by-segment comparison. The mean wall motion score index improved from 2.70 +/- 0.26 to 2.20 +/- 0.71 (P<0.05), with an increased wall motion in eight (89%) patients. A section-by-section analysis demonstrated significantly improved wall motion in the inferior and lateral segments at each ventricular level. Postoperatively, the number of akinetic and markedly hypokinetic segments decreased significantly (P<0.05) from 56 (39%) to 26 (18%) and from 76 (53%) to 56 (37%), respectively. CONCLUSION: CSD implantation improves segmental wall motion, predominantly in the inferior and lateral myocardium, and reduces the number of akinetic and hypokinetic segments.

PRECiSe (priming reduced extracorporeal circulation setup): results of a safety study.

BACKGROUND: Different low-priming systems limited to coronary artery bypass grafting (CABG) have been introduced. We describe the priming reduce d extracorporeal circulation setup (PRECiSe), a new low-priming system that supplies all of the features of cardiopulmonary bypass. METHODS: PRECiSe incorporates the DeltaStream diagonal pump, which pumps blood from the right atrium to the aorta via a membrane oxygenator and a filter. The system is placed beneath the patient's head, resulting in extremely short tubing lengths. A reservoir allows the use of suckers and vents. Autologous blood priming further reduces hemodilution. RESULTS: In the safety study, the system was used for extracorporeal circulation in 11 patients undergoing CABG without the occurrence of any adverse events. By using the PRECiSe system, we reduced the mean priming volume to 268.5 mL, resulting in minimal hemodilution and transfusion requirements. CONCLUSION: The use of PRECiSe for extracorporeal circulation in CABG is safe and reduces priming volume as well as transfusion requirements. Further studies are necessary to investigate the clinical benefit for patients as well a s the use of the system in open heart procedures.

Tissue engineering of an auto-xenograft pulmonary heart valve.

To improve the durability of stentless valves without losing their excellent hemodynamic function, a new-generation auto-xenograft was developed and evaluated. A piece of vein was harvested from 3 juvenile sheep 6 weeks before implantation of the valve. Endothelial cells from the vein material were cultivated and used to reendothelialize a decellularized porcine pulmonary valve. The tissue-engineered valve was implanted into the right ventricular outflow tract of the juvenile sheep. It was explanted after 100 days and assessed macroscopically as well as by x-ray, light microscopy (hematoxylin and eosin staining and von Kossa staining), and scanning electron microscopy. Calcium content of the cusps was determined quantitatively by atomic absorption spectrometry. The sheep implanted with the valve recovered quickly without any problems during the observation period. X-ray examination of the 3 explanted valves showed no cusp calcification, which was confirmed by histological study. Atomic absorption spectrometry showed low tissue calcium content. A clinical safety and feasibility trial with an allograft valve prepared the same way showed excellent short-term results in 6 patients.

Mycotic pseudoaneurysm of the ascending aorta at site of aortic cannulation.

Reoperation for pseudoaneurysm of the ascending aorta presents a surgical challenge. Instituting femorofemoral bypass and establishing hypothermic circulatory arrest is a well-known strategy, although not free from complications. We report a case of mycotic pseudoaneurysm after coronary artery bypass in a 53-year-old man, at the site of previous aortic cannulation, and review the surgical strategies proposed to manage this pathologic entity.