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Objectives Infants and children undergoing cardiopulmonary bypass for repair of congenital heart defects are at substantial risk for excessive bleeding, contributing greatly to morbidity and mortality. Aprotinin significantly reduces bleeding and transfusion requirements in adults but is of indeterminate value for pediatric patients. The aim of this study was to determine plasma aprotinin concentrations in these patients with a functional aprotinin assay. Methods Thirty patients less than 16 years of age scheduled for cardiac surgery with aprotinin were enrolled. Aprotinin was administered as a 25,000 KIU/kg bolus, 35,000 KIU/kg cardiopulmonary bypass prime, and 12,500 KIU · kg −1 · h −1 continuous infusion. Blood samples for aprotinin concentrations (kallikrein-inhibiting units/milliliter) were obtained before aprotinin; 5 minutes post-bolus; 5 minutes after cardiopulmonary bypass initiation; 30 and 60 minutes on cardiopulmonary bypass; on discontinuation of aprotinin; 1 hour after aprotinin discontinuation; and 4 hours after permanent separation from cardiopulmonary bypass. For analysis, patients were grouped according to weight ( 20 kg). Differences between weight groups were assessed using an exact test for categoric variables and 1-way analysis of variance for continuous variables. Results Aprotinin concentrations differed significantly across weight groups. Five minutes after aprotinin bolus and initiation of cardiopulmonary bypass, there was significant correlation between weight and aprotinin concentration ( r = .57, P = .003; r = .69, P = .001, respectively). Conclusion A functional assay reveals significant variability in aprotinin concentration for pediatric patients using current weight-based aprotinin dosing. Additional investigation is necessary to determine target aprotinin concentration dosing regimens to provide better efficacy.

Background Pulmonary ventricle to pulmonary artery conduits have made repairing many complex congenital cardiac anomalies possible. Late patient outcome is adversely affected by the hemodynamic consequences of conduit failure and the need for reoperation for conduit replacement. Methods We retrospectively reviewed 102 patients (65 males, 37 females) who underwent operation with autologous tissue reconstruction ("peel operation") between May 1983 and November 2001, in which a prosthetic roof was placed over the fibrous bed of the explanted conduit. Ages ranged from 5 to 58 years old (median age 19 years old). Explanted conduits were Hancock (n = 54), homograft (n = 21), Tascon (n = 11), and other (n = 16). The conduit roof was constructed with pericardium (n = 91) and other (n = 11). A prosthetic pulmonary valve was utilized in 68 patients: porcine in 65 patients and mechanical in 3 patients. A nonvalved reconstruction was performed in 34 patients. Concomitant cardiac procedures were performed in 66 patients. Results Early mortality overall was 2% (n = 2) and was 0% for patients who underwent isolated conduit replacement (n = 36). Mean follow-up was 7.6 years (maximum, 19 years). Overall survival at 10 and 15 years was 91% (84.7, 97.2) and 76% (62.8, 91.7), respectively. Nine patients required reoperation related to the peel operation: regurgitation in nonvalved conduit (n = 7); moderate pulmonary bioprosthesis stenosis and regurgitation with atrial arrhythmia (n = 1); and pulmonary bioprosthesis endocarditis (n = 1). Overall survivorship free of reoperation for peel reconstruction failure at 10 and 15 years was 90.7% (82.6, 99.6) and 82% (69.4, 97.0), respectively. Survivorship free of reoperation for patients with a prosthetic valve was 93.7%, and for those with no prosthetic valve was 80.0% at 15 years ( p = 0.57). At late follow-up, 89% of patients were in New York Heart Association functional class I or II. Conclusions The peel operation simplifies conduit replacement, can be performed with low risk, and provides a generous-sized flow pathway. In our experience late results demonstrate a lower freedom from reoperation than conventional prosthetic or homograft conduits.

Palliative atrial switch (PAS) procedures that reroute pulmonary and systemic venous drainage and leave a ventricular septal defect (VSD) open have been used in the treatment of deeply cyanotic patients who have severe pulmonary vascular obstructive disease (PVOD). Palliative atrial switch is beneficial for patients with transposition of the great arteries or other complex lesions with VSD who show higher arterial oxygen saturation in the pulmonary artery than in the aorta (transposition hemodynamics/unfavorable streaming). We reviewed the early and late results of PAS (Mustard, n = 25; Senning, n = 3) in patients at two institutions.Between April 1965 and March 2000, PAS was performed in 28 cyanotic patients (18 male, 10 female). Median age was 10 years (range, 1 to 27). Mean preoperative pulmonary arterial pressure was 68 mm Hg (range, 30 to 121 mm Hg). Mean systemic arterial oxygen saturation was 65% (range, 47% to 80%). The majority of patients (95%) were in New York Heart Association (NYHA) functional class III or IV preoperatively.Overall early mortality was 21%; for patients after 1972 (n = 23), the early mortality was 8.7%. Mean follow-up was 8.3 years (maximum 20). Mean postoperative systemic arterial oxygen saturation was increased significantly to 88% (p0.0001). Late survival for early survivors at 5, 10, and 15 years respectively was 84% (59%, 97%), 64% (39%, 88%), and 54% (15%, 72%). The NYHA functional class was significantly improved; 94% of late survivors (n = 17) were in functional class I or II (p = 0.002).The PAS operation significantly improves systemic arterial oxygen saturation and quality of life in selected patients with transposition hemodynamics, VSD, and severe PVOD.

Commonly, in-plane sensitive interferometric optical arrangements use two symmetrical collimated wavefronts for object surface illumination. However, this is a limitation when large objects have to be analyzed. In this case spherical illumination is needed. Non-collimated symmetrical dual-beam techniques have been performed. This kind of illumination produces a sensitivity vector varying with the position. Then errors in the measurements are introduced when collimated illumination is supposed especially in extended target objects. In the present work, an in-plane configuration for electronic speckle pattern interferometer (ESPI) is used. During the design stage of an interferometer should be useful to know the components of sensitivity vector in order to minimize the un-required displacement components. This is main task of this paper. We present theoretical analysis and experimental results for object divergent and collimated illumination. The errors are obtained by comparing the in-plane displacement calculated supposing constant sensitivity vector and spatial variation of sensitivity vector for object divergent illumination. This analysis is made for a flat and cylindrical object surface target.

Objective The modified Fontan procedure, usually performed in children, is used for the treatment of anomalies with a single functional ventricle. We reviewed our experience with the modified Fontan procedure performed in the adult patient. Methods Between October 1973 and May 2001, the modified Fontan procedure was performed on 132 adult patients (74 men, 58 women). Median age was 23 years (range, 18 to 53 years). Diagnoses included tricuspid atresia in 34 patients (26%), double-inlet left ventricle in 48 (36%), and complex lesions in 50 (38%). The majority of patients (89%) had at least one prior palliative procedure; the most common procedures were Blalock-Taussig shunt in 85 patients and Glenn anastomosis in 31. Results Operations included an atriopulmonary connection in 74 patients, lateral tunnel in 27, intra-atrial conduit in 14, right atrium-to-right ventricle in 9, extra-cardiac conduit in 3, and other in 5. Overall early mortality was 8.3%. Mortality was 6.5% for operations performed after 1980. This is comparable to the mortality of the modified Fontan procedure performed in children during the same time interval at our institution. All 7 of the early deaths since 1980 occurred in the complex lesion group. Morbidity included prolonged pleural effusion in 36 patients, atrial arrhythmias in 25, reoperation for bleeding in 13, permanent pacemaker in 8, and stroke in 2. Mean follow-up was 9.1 years with a maximum of 21.2 years. Actuarial survival for early survivors was 89% (84,95), 75% (67,84), and 68% (58,79) at 5, 10, and 15 years, respectively. Freedom from late reoperation was 89% (83,95), 85% (78,93), and 80% (70,91) at 5, 10 and 15 years, respectively. The majority (90%) of present survivors were New York Heart Association class I or II at follow-up. Conclusions In properly selected adult patients with functional single ventricle, the modified Fontan procedure can be performed with early mortality similar to younger patients. Early mortality is more likely with complex lesions. The majority of late survivors have a good quality of life.

Optical interferometry techniques have been used for high-precision displacement measuring. Commonly, in-plane sensitive arrangements use two symmetrical collimated wavefronts for object surface illumination. However, this is a limitation when large object surface, has to be analyzed. In this case spherical illumination is needed. As a consequence of using non-collimated symmetrical dual-beams the sensitivity vector varies with the local position on the surface target. Then, this kind of illumination is also capable of detecting a lightly and systematic out-of-plane component of deformation. In this paper a theoretical analysis of the sensitivity vector components behavior is made. Each component of the sensitivity vector to minimize the required displacement component uncertainty is calculated. This study is important in the stage of planning any interferometric measurement experiment, particularly, for moire grating interferometric technique, which has been used only in collimated illumination. By using a spherical dual-beam optical setup, the present work shows results of fracture measuring by using moire and speckle interferometric methods. As a result, advantages and disadvantages of both techniques are discussed and an accuracy study is reported.

Background Infants and children undergoing cardiopulmonary bypass become substantially hemodiluted secondary to the volume used to prime the oxygenator. Fresh-frozen plasma has been included in the prime to lessen dilution of clotting factors and correspondingly minimize blood loss and transfusions. Methods We prospectively randomized 56 patients weighing 10 kg or less who required cardiopulmonary bypass to receive either one unit of fresh-frozen plasma or 200 mL of albumin 5% in the prime. After protamine administration, samples for prothrombin time, fibrinogen, platelet count, and thromboelastogram were obtained. Mediastinal chest tube drainage and transfusion requirements were documented. Results There were no significant differences between groups regarding demographic or surgical characteristics. Blood loss during the first 24 hours was similar in both groups, but total transfusions were significantly greater in those who received fresh-frozen plasma instead of albumin 5% in the prime (8.0 ± 4.2 versus 6.1 ± 4.5 U, respectively; p = 0.035). Post hoc analyses suggest that for cyanotic patients and patients undergoing complex operations, fresh-frozen plasma in the prime results in less blood loss than albumin 5%. Conclusions Substitution of albumin 5% for fresh-frozen plasma in the prime of acyanotic patients weighing 10 kg or less who undergo noncomplex operations requiring cardiopulmonary bypass significantly reduces perioperative transfusions without increasing blood loss. Further investigation is needed to determine whether increased blood loss is associated with increased transfusions when albumin 5% is substituted for fresh-frozen plasma in the prime of infants and children who are cyanotic or undergoing complex operations.

Objective: This study was undertaken to further define the impact of intraoperative transesophageal echocardiography during surgery for congenital heart disease and to determine appropriate indications. Methods: The impact of transesophageal echocardiography on patient care was assessed in 1002 patients who underwent this procedure during surgery for congenital heart defects. It had major impact when new information altered the planned procedure or led to a revision of the initial repair. The safety of intraoperative transesophageal echocardiography was evaluated by review of the prospective data sheets and the medical record. A simple relative cost analysis was also performed. Results: Patient median age was 9.9 years (range 2 days to 85 years). Transesophageal echocardiography had prebypass or postbypass major impact in 13.8% of cases (n = 138/1002). Major impact was more frequent during reoperations (P

Objective: We sought to determine the results of surgical treatment of patients with tetralogy of Fallot and pulmonary atresia with or without major aortopulmonary collateral arteries, to clarify variables affecting early and late mortality, and to expose late, nonfatal events affecting surgical patients. Methods: The records of 495 patients operated on from 1977 to 1999 were reviewed. Patients were separated into those who did not undergo complete repair (group A) and those who did (group B). Results: Group A consisted of 160 patients. Eighty-one (51%) had palliative procedures, 45 (28%) had preliminary surgical stages (unifocalization and right ventricular outflow tract reconstruction) as initial operations, and 34 (21%) had all surgical stages but were rejected for complete repair. Early and late mortality were 16.3% (n = 26) and 23.1% (n = 31), respectively. Mean follow-up was 72.3 months. The presence of major aortopulmonary collateral arteries was a risk factor for late mortality ( P =.0182). Group B consisted of 335 patients. Mean age at complete repair was 11.3 years (SD, 9.2). One hundred three (30%) patients had single-stage complete repair, whereas 232 (69%) had staged reconstruction. Twenty-two (6.6%) patients underwent reopening of the ventricular septal defect for high right ventricular pressure. Early and late mortality were 4.5% (n = 15). Risk factors were a peak right ventricular/left ventricular pressure ratio of greater than 0.7 and reopening of the ventricular septal defect ( P ≤.05). Late mortality was 16% (n = 51). Mean follow-up was 11.4 years (SD, 7.5). Risk factors included male sex, nonconfluent central pulmonary arteries, reopening of the ventricular septal defect, and postrepair conduit exchange (n = 137). Ten- and 20-year results were an actuarial survival of 86% and 75% and freedom from reoperation of 55% and 29%, respectively. Conclusions: Surgical repair of patients with simple or complex forms of tetralogy of Fallot with pulmonary atresia can be achieved with low early mortality. Late mortality and need for reoperation, especially conduit replacement, continue to affect the long-term well-being of these patients. J Thorac Cardiovasc Surg 2002;124:70-81

The first successful surgical correction of truncus arteriosus (common arterial trunk) was performed in 1967 and long-term follow-up is now available on 137 operative survivors. Actuarial survival was 46.4% at 24 years. Late survival was statistically significantly improved in patients having correction during the first 2 years of life when compared to those corrected after the age of 2. Late mortality was secondary to reoperation, most commonly for truncal valve replacement, progressive pulmonary vascular obstructive disease and right ventricular failure, or progressive left ventricular deterioration and failure. Reoperation for isolated conduit replacement was associated with low mortality (one death in 54 reoperations) and morbidity. Reoperation for truncal valve replacement was frequently necessary in patients showing significant truncal incompetence immediately after operative correction, but had not been observed in any patients showing no or minimal incompetence at the time of initial hospital discharge. Of the 86 presently surviving patients, many of whom are now adults, 78 (91%) were NYHA Class I or II, capable of full-time school or employment, at the time of most recent follow-up. Operative correction of truncus arteriosus is now possible at low mortality during the first few months of life, and this is the approach now utilized in all centers to relieve the large left ventricular volume load and its detrimental effects on left ventricular function as soon as possible, as well as to minimize the risk of irreversible pulmonary vascular obstructive disease. With this present approach, late mortality and morbidity could be expected to be significantly less in infants operated today than the late results seen in our unique group of patients corrected, for the most part, at older ages, many even as adolescents or young adults. An infant born with truncus arteriosus today has an excellent chance of survival with good quality of life well into adulthood years.

Out-of-plane configurations used in electronic speckle pattern interferometry (ESPI), introduce phase error interpretation in extended target objects due to spatial variation of the sensitivity vector. In this paper, a general model to predict and correct the displacement measurement error and error phase map interpretation taking into account the target shape, illumination geometry, and in-plane displacement information, is presented. This model generalizes and extends previous analyses with respect to the sensitivity vector variations. The model is based on a relationship between variable sensitivity vector and the constant one. The importance of illumination geometry and in-plane displacement as factors that introduce the biggest error in the interpretation of the phase map are stressed. An analysis with practical parameters using divergent and collimated beams is presented. In order to predict and correct the error of phase interpretation, the finite element method should be used to obtain in-plane proportional factors to build up the correction function. The analysis shows that the error can be large for common configurations even when using collimated beam. To compute the measurement directly from the phase map, a general sensitivity function taking into account the shape and in-plane displacement information is naturally obtained from the presented analysis.

The Rastelli operation, first performed in 1968, was developed for repair of transposition of the great arteries with associated ventricular septal defect and severe pulmonary stenosis. This operation includes placement of an intracardiac baffle to direct left ventricular blood to the aorta and an extracardiac valved conduit to establish continuity between the right ventricle and the pulmonary arteries. Over the last 3 decades, the Rastelli operation has been performed with a progressive decline in early mortality, and it remains the preferred repair for transposition, ventricular septal defect, and severe fixed valvular or subvalvular pulmonary stenosis. This chapter examines the late results of our 33-year experience with the Rastelli operation and describes our operative technique.

The Fontan procedure in one of its many modifications is applicable to the surgical treatment of those patients with double-outlet right ventricle who are not amenable to bi-ventricular correction. Included in this group are patients with significant hypoplasia of one of the ventricles, patients with distant (non-committed) ventricular septal defect, patients with significant straddling of the atrioventricular valves, patients with abnormal atrioventricular connections (such as absence of one of the valves), or common atrioventricular valve connection. The presence of complex associated lesions such as those seen in the heterotaxia syndromes may, by virtue of the surgical risk of attempts at bi-ventricular repair, make the Fontan approach a suitable option for these patients. The presence of a subaortic conus and the potential for subaortic obstruction, a frequent findings in patients with double outlet right ventricle, plays an important role in the preparation and conduct of the Fontan operation. Copyright © 2000 by W.B. Saunders Company

Es prematuro intentar establecer una comparacion entre los resultados obtenidos en el reemplazo valvular aortico con las denominadas tecnicas «minimamente invasivas » y los que se obtienen rutinariamente usando la esternotomia media. La casuistica disponible con los procedimientos de abordaje limitado es aun reducida y quizas anecdotica. Entre cien enfermos consecutivos operados por esternotomia media en la Clinica Mayo, hubo un caso de muerte hospitalaria. La duracion media de la circulacion extracorporea fue de 72 min; la duracion media de pinzamiento aortico fue de 50 min. No hubo ningun caso de sangrado o de infeccion postoperatoria. La duracion media de hospitalizacion fue de 6,4 dias. Estos resultados son semejantes a los obtenidos mediante las tecnicas de abordaje limitado.

Coronary artery aneurysms are defined as localized coronary artery dilations >1.5 times the diameter of the adjacent segments. In adults, they are commonly of atherosclerotic origin and are usually asymptomatic. This is the first case report of a coronary artery aneurysm causing superior vena cava syndrome and heart failure. Chest x-ray showed cardiomegaly, and transthoracic echocardiography showed a mass that was confirmed by transesophageal echocardiography, computed tomography, and coronary angiography. In conclusion, giant coronary artery aneurysms can cause superior vena cava syndrome.

A small electromagnetic sampling calorimeter, installed in the ZEUS experiment in 1995, significantly enhanced the acceptance for very low x and low Q 2 inelastic neutral current scattering, e+p → e+X, at HERA. A measurement of the proton structure function F2 and the total virtual photon-proton ( γ ∗ p ) cross-section is presented for 0.11 ≤ Q 2 ≤ 0.65 GeV2 and 2 × 10−6 ≤ x ≤ 6 × 10−5, corresponding to a range in the γ ∗ p c.m. energy of 100 ≤ W ≤ 230 GeV. Comparisons with various models are also presented.

Objectives. This study sought to measure the cardiorespiratory responses to exercise and to identify the perioperative determinants of exercise performance in children, adolescents and young adults who underwent the modified Fontan operation. Background. Several studies of the cardiorespiratory responses to exercise after the Fontan operation have demonstrated subnormal maximal oxygen uptake and exercise heart rate, but the perioperative variables that ultimately affect exercise responses have not been assessed systematically. Methods. The study included 59 of the 548 patients who underwent a modified Fontan operation between January 1, 1984 and December 31, 1993 at the Mayo Clinic. Spirometry was performed at rest in all patients before exercise testing. The patients then exercised using a previously calibrated cycle ergometer and a 3-min incremental cycle exercise protocol. Multiple linear regression analysis was used to determine a subset of variables associated with oxygen uptake at peak exercise (Vo2max), blood oxygen saturation (O2sat) and heart rate at peak exercise (HRmax). Results. Vo2max ranged from 29% to 95% of normal value; O2sat at peak exercise ranged from 77% to 96%; and HRmax ranged from 39.7% to 97.4% of normal value. Multivariate analysis showed that log Vo2max/kg2/3was associated with age at exercise, male gender, body surface area, preoperative confluent pulmonary arteries and rest Vo2max/kg2/3. Preoperative left pulmonary artery stenosis, the presence of a classic Glenn anastomosis at exercise and rest O2sat were associated with O2sat at peak exercise. Age, body surface area at exercise, heart rate at rest and diastolic blood pressure were associated with HRmax at exercise. Conclusions. Subnormal Vo2max and HRmax values were demonstrated at peak exercise. Several perioperative variables were associated with Vo2max and O2sat at peak exercise. The presence of a classic Glenn anastomosis was associated with decreased O2sat at peak exercise, suggesting intrapulmonary shunting with the classic Glenn anastomosis. (J Am Coll Cardiol 1997;29:785–90)

The antimicrobial activity of vancomycin and related glycopeptide antibiotics is due to stereospecific recognition of polypeptide components in bacterial cell walls. To better understand how these antibiotics recognize polypeptide determinants, we have developed dynamic models of the complexes formed by the vancomycin aglycon and two different dipeptide ligands, Ac-D-ala-D-ala and Ac-D-ala-gly. Molecular dynamics simulations of the two complexes, initially conditioned with distance constraints derived from two-dimensional nuclear magnetic resonance (NMR) studies, are conformationally stable and propagate in a manner consistent with the NMR-derived constraints after the constraints are removed. Free energy calculations accurately predict the relative binding affinity of these two complexes and help validate the simulation models for detailed structural analysis. Although the two ligands adopt similar conformations when bound to the antibiotic, there are clear differences in the configuration of intermolecular hydrogen bonds, the overall shape of the antibiotic, and other structural features of the two complexes. This analysis illustrates how complex structural and dynamic factors interrelate and contribute to differences in binding affinity. © 1997 John Wiley & Sons, Ltd.

Considerable effort and expense has been invested in the evolutionary development of cardiac valvular prostheses with the goal of reducing or minimizing specific events related to these prostheses. It is important to measure any improvement achieved with such development by comparison against a historic standard. The Starr-Edwards caged-ball prosthesis model 1260 has been used for 30 years as the predominant or sole model of its kind for aortic valve replacement. This historic opportunity provides a benchmark for subsequent improvement and comparison of current prostheses.Between 1969 and 1991, 1,100 patients (median age, 57 years; 838 men and 194 women) underwent aortic valve replacement with or without coronary artery bypass grafting (aortic valve replacement, 964; aortic valve replacement plus coronary artery bypass grafting, 136) with the 1260 Starr-Edwards caged-ball prosthesis.Operative mortality was 6.2% (68 patients). Univariate patient characteristics predictive of early mortality were female sex (p = 0.003), age (56 years; p = 0.002), recent operative interval (1985 to 1991 versus 1969 to 1976 or 1977 to 1984; p = 0.002), presence of atrial fibrillation (p = 0.001), and small valve size (7A to 8A = 19 to 21 mm; p0.001). Follow-up extended to 11,293 patient-years (mean, 24.8 years) and was 96.9% complete. Survival at 5, 10, 15, and 20 years for all patients including operative mortality was 76.6%, 59.6%, 44.9%, and 31.2%, respectively. Operative variables predictive of poor late survival were advanced New York Heart Association class (III or IV); (p = 0.0001), older age (56 years; p = 0.0001), and lower (0.56) ejection fraction (p = 0.0001). Freedom from thromboemboli and anticoagulant-related bleeding at 5 years was 90.8% and 98.7%, respectively. Univariate model for greater risk of late thromboemboli identified female sex (p = 0.04), older age (56 years; p = 0.0002), and New York Heart Association class III or IV (p = 0.0058), as risk factors. Multivariate analysis for thromboemboli demonstrated older age (p = 0.0007) and New York Heart Association class III or IV (p = 0.0041) as significant. Alternatively, univariate analysis for late bleeding found only the most recent operative interval (p = 0.009) as significant, and the rarity of events prevented a multivariate query. There were no valve failures.The late results of survival and freedom from late anticoagulant-related bleeding or thromboemboli are excellent, especially in larger (9A and above) sizes, and with the long implant record comparable with more recent prostheses, the Starr-Edwards valve provides an excellent, safe, and durable alternative in the aortic position and provides a benchmark against which to compare other prostheses.

Irreparable mitral pathology may lead to early mitral valve replacement (MVR) in children. Often, a small mechanical prosthesis (2, had an annular size of 24 ± 0.62 mm ( Z score, 2.91 ± 0.23), and ultimately did not require MVRR. Another cohort, who eventually did require MVRR (n = 24), had an initial BSA at the time of MVR of 0.62 ± 0.05 m2 ( P = NS vs MVR only) and an annular size of 20 ± 0.49 mm ( Z score, 1.85 ± 0.22) ( P = .008 vs MVR only). In the interval between MVR and MVRR (7.8 ± 1.1 years), BSA increased to 1.12 ± 0.07 m2, and annulus size increased to 24 ± 0.47 mm ( Z score, 1.80 ± 0.28). These data suggest growth of the mitral annulus following MVR with a small mechanical prosthesis, as evidenced by an unchanged Z score in the setting of normal interval increase in BSA. Additionally, there was a statistically significant difference in initial Z scores between the cohorts requiring MVRR and those who have not needed re-replacement, suggesting that the feasibility of placement of a slightly larger prosthesis may be associated with a decreased need for MVRR.

Patients were observed after the Fontan operation to determine the frequency and severity of protein-losing enteropathy. A total of 427 patients who survived for 30 days after the Fontan operation, performed between 1973 and January 1987, were analyzed and, thus far, protein-losing enteropathy has developed in 47 of 427. The cumulative risk for the development of protein-losing enteropathy by 10 years was 13.4% among 30-day survivors, and 5-year survival after the diagnosis was 46%. Hemodynamic studies done coincident with the diagnosis of protein-losing enteropathy have shown increased systemic venous pressure, decreased cardiac index, increased pulmonary vascular resistance, and increased ventricular end-diastolic pressure. Medical management of protein-losing enteropathy was only partially successful. Statistical analysis has shown that factors related to protein-losing enteropathy were ventricular anatomy, increased preoperative ventricular end-diastolic pressure, longer operative bypass time, increased length of hospital stay, and postoperative renal failure. This study suggests that scrupulous selection of cases for the Fontan operation is mandatory and that certain perioperative factors may predispose to this serious complication of the Fontan procedure. (J THORAC CARDIOVASC SURG 1996;112:672-80)

Deep inelastic charged-current reactions have been studied ine+p ande−p collisions at a center of mass energy of about 300GeV in the kinematic regionQ2>200GeV2 andx>0.006 using the ZEUS detector at HERA. The integrated cross sections forQ2>200GeV2 are found to be \(\sigma _{e^ + p \to \bar \nu X} = 30.3_{ - 4.2 - 2.6}^{ + 5.5 + 1.6} pb\) and \(\sigma _{e^ - p \to \nu X} = 54.7_{ - 9.8 - 3.4}^{ + 15.9 + 2.8} pb\). Differential cross sections have been measured as functions of the variablesx, y andQ2. From the measured differential cross sectionsdσ/dQ2, theW boson mass is determined to be \(M_W = 79_{ - 7 - 4}^{ + 8 + 4} GeV\). Measured jet rates and transverse energy profiles agree with model predictions. A search for charged-current interactions with a large rapidity gap yielded one candidate event, corresponding to a cross section of \(\sigma _{e^ + p \to \bar \nu X} (Q^2 > 200 GeV^2 ; \eta _{\max }< 2.5) = 0.8_{ - 0.7}^{ + 1.8} \pm 0.1 pb\)

Elasticρ0 photoproduction has been measured using the ZEUS detector at HERA. Untagged photoproduction events fromep interactions were used to measure the reactionγp→ρ0p(ρ0)→π+π−) at photon-proton centre-of-mass energies between 60 and 80 GeV and |t

We report on a measurement of the proton structure function F 2 in the range 3.5×10-5≤x≤4×10-3 and 1.5 GeV2≤Q 2≤15GeV2 at the ep collider HERA operating at a centre-of-mass energy of √s=300GeV. The rise of F 2 with decreasing x observed in the previous HERA measurements persists in this lower x and Q 2 range. The Q 2 evolution of F 2, even at the lowest Q 2 and x measured, is consistent with perturbative QCD. © 1996 Springer-Verlag.

Background. Congenital pulmonary vein stenosis is a rare cause of obstruction of pulmonary venous blood flow with a high mortality. Acquired pulmonary vein stenosis is an equally serious condition. Methods. Eight patients (age range, 3 months to 43 years; median age, 1.5 years) underwent surgical relief of pulmonary vein stenosis. Two had congenital pulmonary vein stenosis, 5 had pulmonary vein stenosis that was acquired after surgical treatment of total anomalous pulmonary venous connection, and 1 had pulmonary vein stenosis associated with idiopathic mediastinal fibrosis and calcification. Results. One infant died 2 months after correction of acquired pulmonary vein stenosis. At follow-up extending to 16 years (median follow-up, 6.5 years), 6 patients are in New York Heart Association functional class I, and 1 patient is in class II. Conclusions. In view of the dismal natural history of untreated pulmonary vein stenosis, prompt surgical relief of the stenosis may be a rewarding undertaking.

To better understand risk factors associated with early postoperative death or failure, we reviewed our entire experience with 702 consecutive patients who had the modified Fontan operation at the Mayo Clinic between October 1973 and December 1989. The event rate for takedown of repair or death during the initial hospitalization or within 30 days of the operation was 14.8% (successful takedown of the repair, n = 6; death, n = 98). To identify variables associated with early death or Fontan takedown, we analyzed 33 clinical and hemodynamic variables in a univariate and multivariate manner. On the basis of a stepwise logistic discriminant analysis, patients who were younger and operated on before 1980 with a higher preoperative pulmonary artery mean pressure, asplenia, higher intraoperative (after Fontan operation) right atrial pressure, longer aortic crossclamp time, and pulmonary artery ligation were more likely to have the outcome event of interest ( p values p = 0.002), but was no more predictive than the preoperative pulmonary artery mean pressure. Variables less predictive of the outcome event in this analysis included multiple prior operations, polysplenia syndrome, complex anatomy other than asplenia syndrome, and systemic atrioventricular valve regurgitation. These results represent the largest single-institution review of the Fontan operation and suggest that some anatomic and hemodynamic variables previously predictive of poor early outcome have been nullified by current operative methods. (J THORAC CARDIOVASC SURG 1995;109:1237-43)

Objective To describe a 30-year experience with surgically treated culture-positive active endocarditis. Design We retrospectively reviewed the microbiologic, clinical, and operative findings and the survival data in 151 patients with culture-positive active endocarditis encountered between 1961 and 1991. Results The mean age of the 110 male and 41 female patients was 49.8 years. Native valve endocarditis was present in 86 patients, and prosthetic valve endocarditis (PVE) was diagnosed in 65. The aortic valve was involved in 62 % of patients, the mitral valve in 25%, and both valves in 10%. The operative mortality was 26%. The most important univariate determinants of mortality were an abscess at operation ( P = 0.01) and renal failure ( P = 0.03). A trend toward a higher mortality with PVE and staphylococcal infection was noted. For hospital survivors, the 5- and 10-year survival was 71 % and 60%, respectively. Univariate determinants of an adverse longterm survival were annular abscess ( P = 0.01), renal impairment (P = 0.01), heart failure ( P = 0.02), and aortic valve involvement ( P = 0.05). On multivariate analysis, the most important adverse determinants of long-term survival were heart failure ( P = 0.02), renal impairment ( P = 0.02), and PVE ( P = 0.03). Thirty patients required a subsequent reoperation; of these, seven required a second and two a third operation. The most common reason for reoperation was periprosthetic regurgitation without infection (N = 19). Four operations were performed for recurrent endocarditis. At 5 and 10 years, the risk of reoperation was 23% and 36%, respectively. Conclusion Although surgical treatment of culture-positive active endocarditis is still associated with substantial mortality, the long-term outcome of hospital survivors is excellent. Subsequent reoperations for periprosthetic leak are common, but recurrent infection is uncommon.

An instrument has been developed to acquire polarized attenuated total internal reflection (ATIR) mid-IR spectra of supported monomolecular films in situ at the lipid/water (L/W) interface. The monolayer film is applied to the treated surface of a trapezoidal germanium crystal as it is immersed into the subphase of a specially designed Langmuir-Blodgett trough. This approach offers several advantages over the study of monolayer films at the air/water (A/W) interface by external reflection techniques, including (1) an improved signal throughput and multiple reflections, both contributing to an improved signal-to-noise (S/N) ratio; (2) versatility with respect to the chemical nature of the surface; and (3) the ability to use standard spectral subtraction methods to compensate for absorption of the aqueous subphase. The enhanced sensitivity of this approach facilitates the study of in situ interactions of peptides with fully hydrated lipid membrane surfaces.

Events with a large rapidity gap and total transverse energy greater than 5 GeV have been observed in quasi-real photoproduction at HERA with the ZEUS detector. The distribution of these events as a function of the $\gamma p$ centre of mass energy is consistent with diffractive scattering. For total transverse energies above 12 GeV, the hadronic final states show predominantly a two-jet structure with each jet having a transverse energy greater than 4 GeV. For the two-jet events, little energy flow is found outside the jets. This observation is consistent with the hard scattering of a quasi-real photon with a colourless object in the proton., Comment: 19 pages, latex, 4 figures appended as uuencoded file

All patients (285) undergoing mitral valve replacement (MVR) with a Carpentier-Edwards (C-E) bioprosthesis +/- coronary bypass grafts (CABG) were reviewed (109 men and 176 women with a median age of 70 years). Overall, the 5-year survival rate was 58.9%, 62.7% for MVR (199 patients) and 50.1% for MVR+CABG (86 patients). Late survival was adversely affected by the operative time variables of NYHA class IV, older (> or = 70 years) age, low (> or = 56%) ejection fraction (EF), and the additional performance of associated procedures+CABG with MVR (P < or = 0.001). The 5-year freedom from stroke rate was 89.2%, 89.1% for MVR and 90.2% for MVR +/- CABG. Advanced heart class was the only significant variable associated with a greater risk of late stroke (P < or = 0.01). Neither chronic preoperative atrial fibrillation nor operative obliteration of the left atrial appendage increased or decreased the late risk of stroke in patients following MVR. Hazard function for stroke occurring in the first postoperative year (first 48 h excluded to discount intraoperative events) demonstrated the highest rate within the first month (40%), rapidly diminishing thereafter. This pattern was reproduced in the 12-year hazard function in that the rate of stroke occurrence was greatest in the first year (6.7%) following implantation. The mean stroke rate over 12 years was 2.5%. Strokes following MVR +/- CABG are more likely to occur in older and more compromised patients, and the higher early rate is not reflected in the mean rate. A more aggressive approach to early anticoagulation with IV heparin, Coumadin, and possibly antiplatelet therapy is advocated to reduce this complication rate.

Knowledge of the variations in coronary artery pattern is important in the arterial switch operation for complete transposition of the great arteries (TGA). As autopsy specimens provide the most definitive means of identifying the coronary anatomy, 255 hearts with complete TGA were reviewed by a single pathologist. The age of the patients ranged from 1 day to 34 years (mean, 2.9 years). The origin of the coronary arteries was defined as seen by an observer looking from the pulmonary artery toward the aorta. The usual pattern with the right coronary artery originating from the right hand sinus and the left coronary artery from the left hand sinus (184 cases) and the circumflex coronary artery arising from the right coronary artery (46 cases) accounted for 90% of the cases. Eleven other patterns were identified. The usual coronary artery pattern was more prevalent in TGA with the aorta in a right anterior or anterior position (74.8%) than in TGA with a side-by-side relationship of the great arteries (38.9%). In only 2 cases (0.8%) was an aortic intramural course of the left coronary artery identified. The latter 2 cases confirm our belief that an aortic intramural course of the left coronary artery or the left anterior descending coronary artery must be assumed when the vessel has an aberrant origin from the right sinus or when it is in intimate relationship with the commissure between the right and left sinuses and courses between the great arteries. In the vast majority of specimens a favorable coronary artery pattern with regard to feasibility of the arterial switch operation was encountered.

Thirty-nine patients have undergone operation for relief of tracheoesophageal compression resulting from vascular rings and related entities at the Mayo Clinic. Nineteen patients had a double aortic arch, 11 patients had a right aortic arch with an aberrant left subclavian artery, 5 patients had a left aortic arch with an aberrant right subclavian artery, 2 patients had a pulmonary artery sling, 1 patient had a right aortic arch with mirror-image branching and a left ligamentum arteriosum, and 1 patient had a left aortic arch, a right descending aorta, and a right ductus arteriosus. Diagnostic examinations included chest radiography, barium esophagography, angiography, and, more recently, transthoracic echocardiography, computed tomography, and magnetic resonance imaging. A comparison among the various diagnostic techniques used in 12 patients during the last 12 years showed that angiography (n = 7), magnetic resonance imaging (n = 5), and computed tomography (n = 3) were the most reliable, as they always accurately delineated the anatomy. However, in the 6 patients who underwent transthoracic echocardiography, 1 of whom was an older child and 2 of whom were adults, the vascular abnormality was described correctly only once; in the other 5 patients, the results were false-negative or the technique failed to visualize the relevant vascular structures sufficiently. Currently, magnetic resonance imaging is our imaging technique of choice for the delineation of the vascular and tracheal anatomy in patients suspected of having a vascular ring.

To determine long-term outcome after operation for supravalvular aortic stenosis, we reviewed the case histories of 80 patients who had repair of the localized form (group A) (n = 67) or diffuse form (group B) (n = 13) from 1956 to 1992, including 31 patients with the Williams-Beuren syndrome. Ages ranged from 7 months to 54 years (mean = 12.6 years). Forty-six patients had one or more associated cardiovascular anomalies; the most common was aortic valve stenosis (33.8%). Eighteen patients had 22 previous cardiovascular operations, and 28 patients had one or more additional anomalies repaired during their initial procedure at our institution. In group A, the aortic root was enlarged with a teardrop-shaped patch (n = 61) or a pantaloon-shaped patch (n = 6). In group B, patch enlargement of the aorta was confined to the root (n = 4) or extended into the ascending aorta or aortic arch (n = 7); one patient had a graft placed between the ascending and descending thoracic aorta and one patient had a left ventricular-aortic conduit. There were no deaths in group A; two patients in group B in whom patch enlargement was confined to the aortic root died during the operation (2.5%). Follow-up extended to 33.4 years (mean = 14.2 years); there were five late deaths in group A and one in group B. Survival excluding operative mortality was 94% at 10 years and 91% at 20 years. All patients were in functional class I or II. There was no significant difference between patients with a teardrop-shaped or pantaloon-shaped patch in terms of late gradient, survival, or aortic insufficiency. By Cox multivariate model, the only independent predictor of late death for all patients was associated aortic valve disease (p = 0.02), which was also a risk factor for late reoperation (p = 0.02). In group B, overall survival was better in patients who received an extended patch versus aortic root patch only (p = 0.02). We reached the following conclusions: (1) Associated aortic valve disease was strongly correlated with late death and need for reoperation. (2) Both the teardrop-shaped and pantaloon-shaped patch techniques provide excellent long-term relief of localized supravalvular gradients and preservation of aortic valve competence. (3) In diffuse supravalvular aortic stenosis, aortic enlargement should be extended into the ascending aorta or beyond as required to relieve the gradient; some patients may require a graft or conduit.(ABSTRACT TRUNCATED AT 400 WORDS)

We reviewed medical records from eight patients (4 to 29 years of age) with a functional single ventricle and pulmonary microthrombosis as observed on open lung biopsy specimens. Hemodynamic assessment before biopsy revealed pulmonary hypertension (mean pulmonary artery pressure 19 to 53 mm Hg) in the seven patients tested and severely increased pulmonary arteriolar resistance (6 to 13 U · m2) in three of the five patients in whom these measurements were performed. Pulmonary blood flow varied ( 5 L/min per square meter in four patients), and the pulmonary/systemic blood flow ratio was low or normal (0.6 to 1.1) in five of six cases. Hemoglobin values were increased (16.4 to 22 gm/dl) in seven of eight patients. Lung biopsy specimens revealed thrombotic obstructive lesions in 56 % (range 28% to 96%) of muscular pulmonary arteries. Coexistent medial hypertrophy was absent or mild in all but one specimen, and none had features of plexogenic pulmonary arteriopathy. Microscopic pulmonary thrombi accounted for unexpected pulmonary hypertension, precluding the Fontan operation, in five patients and unsuccessful Fontan operation in two. Clinically significant thrombi should be considered in patients with severe polycythemia (hemoglobin value >20 gm/dl) and unobtainable or unreliable pulmonary blood flow or pulmonary resistance determinations. ( J Thorac Cardiovasc Surg 1993;106:739-44)

The preparation and characterization of two discrete, mixed-metal, hexanuclear transition-metal borides, trans-[Fe 4 Rh 2 (CO) 16 B] - and mer-H 2 Fe 3 Rh 3 (CO) 15 B, are described

Pseudorandom and random numbers generators, plays an important role in solving many real or simulated problems, in different domains such as Scientific Computing, Physics, Chemistry, Computer Science, Artificial Intelligence, Chaos, Games theory, Statistics, Economics, etc. that directly or indirectly include a probabilistic element. These generators can be found in calculators, compilers, spreadsheets, electronics files or library tables, However, the progressive use of increasingly sophisticated models will demand a fast pseudorandom number generation process, which can generate strings of arbitrary sizes, and ensure it’s reproducibility, uniformity and statistical independence, hence it constitutes an active research field area. This paper presents a novel method for obtaining these numbers relevant to various branches of computational optimization.

Address correspondence to Robert H. Feldt, M.D., Section of Pediatric Cardiology, Mayo Clinic, Rochester, MN 55905. in young infants with PA-VSD, especially when the entire pulmonary flow is reduced and supplied only from a closing ductus arteriosus. 2"4 Other patients with excessive pulmonary blood flow through a large patent ductus arteriosus and/or collateral arteries may have signs of congestive heart failure and minimal cyanosis. 4-6 The nature of the pulmonary blood supply in many of these patients is quite complex and each patient often has a unique pulmonary circulation based on the number, size, and patency of collaterals; the presence and size of the pulmonary artery confluence; and the nature of the connections between the collaterals and the true arterial tree. 7 Castaneda and coworkers have classified the anatomy of PA-VSD into four subtypes (see their article in this issue). ,Paroxysmal attacks of dyspnea and squatting occur in some patients with PA-VSD. 3 Hemoptysis from rupture of extensive systemic-to-pulmonary

In 1984 we reported a 56 % mortality after major cardiac operations for patients with univentricular connection to a dominant left ventricle, an anterior subaortic outlet chamber, and subaortic obstruction. Since then we have adopted a staged approach to this repair. Between 1984 and 1989 32 patients had such operations. The overall mortality has decreased (16%; p horac C ardiovasc S urg 1992; 104:1231-7)

BACKGROUND The purpose of this study was to estimate survival and quality of outcome and assess factors associated with outcome for patients out 5 to 15 years from their Fontan operation. METHODS AND RESULTS We studied 352 patients who had the Fontan operation prior to 1985. The overall 1-, 5-, and 10-year survival was 77%, 70%, and 60%, respectively. The following factors were significantly associated with lower survival: univentricular heart or complex congenital anomalies other than tricuspid atresia, early calendar year of operation, heterotaxia syndromes, early age at operation, increased pulmonary artery pressure, atrioventricular valve dysfunction, and higher (worse) New York Heart Association class. Reoperations were necessary for 103 of the 352 patients. At least 20% of the survivors have or have had cardiac arrhythmias requiring antiarrhythmic medication or mechanical pacemaker insertion. Between 7% and 10% of the patients have had or had protein-losing enteropathy/hypoproteinemia. At 5 years postoperatively, 122 patients (34.7%) were alive with a better New York Heart Association functional classification than preoperatively. Fifty-eight patients (16.5%) were alive and in the same functional classification, but 126 (35.8%) died within the first 5 years or were in a worse functional classification. Thirty-nine patients were doing excellently and 29 patients poorly 5 years after the operation. Of the surviving patients, 43% can do as much exercise as their peers, whereas 3% are incapable of exercise. CONCLUSIONS To assure good functional long-term outcome in addition to survival, clinicians must exclude from selection for Fontan operation patients known to be at high risk for death or poor outcome.

The preparation and characterization of two discrete, mixed-metal, hexanuclear transition-metal borides, trans-[Fe 4 Rh 2 (CO) 16 B] - and mer-H 2 Fe 3 Rh 3 (CO) 15 B, are described

Background— Primary cardiac tumors are rare but have the potential to cause significant morbidity if not treated in an appropriate and timely manner. To date, however, there have been no studies examining survival characteristics of patients who undergo surgical resection. Methods and Results— From 1957 to 2006, 323 consecutive patients underwent surgical resection of primary cardiac tumors; 163 (50%) with myxomas, 83 (26%) with papillary fibroelastomas, 18 (6%) with fibromas, 12 (4%) with lipomas, 28 (9%) with other benign primary cardiac tumors, and 19 (6%) with primary malignant tumors. Operative (30 day) mortality was 2% (n=6). Univariate analysis indicated that patients who underwent resection of fibromas and myxomas had superior survival characteristics in comparison to the remainder of tumor variants; these results were consistent after adjusting for age at surgery, year of surgery, and cardiovascular risk factors. Based on actuarial characteristics of the 2002 U.S. population, patients who underwent myxoma resection had survival characteristics that were not significantly different from that of an age and gender matched population (SMR 1.11, P =0.57) whereas those who underwent resection of fibromas (SMR 11.17, P =0.002), papillary fibroelastomas (SMR 3.17, P =0.0003), lipomas (SMR 5.0, P =0.0003), other benign tumors (SMR 4.63, P =0.003), and malignant tumors (SMR 101, P P P =0.003) with the risk of recurrence decreased after 4 years. Conclusions— Surgical resection of primary cardiac tumors is associated with excellent long-term survival; patients with cardiac myxomas have survival characteristics that are not significantly different from that of a general population. Predictors of mortality are primarily related to tumor histology but also include clinical characteristics such as symptomatology and duration of CPB.

The long-term benefits of mitral regurgitation (MR) surgery in ischemic cardiomyopathy (ICM) are controversial. Herein are reported the results and trends of this surgical approach over the past 24-year period.Patients were identified in refractory heart failure due to ICM with NYHA functional class III/IV symptoms, left ventricular ejection fractionor =35% and MR who underwent mitral surgery between 1979 and 2002. The early and late outcomes were analyzed and compared for the different surgical eras classified as early (1979 to 1986), middle (1987 to 1994), and late (1995 to 2002).Mitral repair (70%) and replacement (30%) were performed with coronary artery bypass grafting (CABG) (85%) and tricuspid valve repair (7%) in 179 patients (mean age 68 +/- 9 years). The overall one- and five-year survival rates were 84% and 51%, respectively, and the corresponding freedom from recurrent MR after repair 86% and 55%. An increasing number of patients underwent surgery from the early to the late era. Whereas patients more frequently presented with cardiomegaly and renal failure during the early era, they were older, more often had prior CABG, concurrent tricuspid regurgitation and underwent mitral repair during the late era. A progressive improvement was observed in operative mortality from the early to late eras (24%, 11% and 5%, respectively; p = 0.009), and also for the one-and five-year survivals (68%, 85% and 89%; 46%, 43% and 57%, respectively; p = 0.06). Preoperative renal failure and concomitant tricuspid valve repair were predictors of late mortality.During the past 24 years, operative results for the surgical correction of MR in patients with heart failure due to ICM have steadily improved. Currently, while the early and mid-term survival are satisfactory the long-term survival is limited, especially when heart failure is complicated by renal failure and severe tricuspid regurgitation.

Background. Atrial septal defects have been surgically correctable for more than 30 years. The long-term survival rates among patients treated in the early era of cardiac surgery are poorly documented, but such data are of critical importance to the future medical care, employability, and insurability of these patients. Methods. To determine the natural history of surgically corrected atrial septal defects, we studied all 123 patients who underwent repair of an isolated defect (ostium secundum or sinus venosus) at the Mayo Clinic between 1956 and 1960, 27 to 32 years after the procedure. The follow-up status of all patients was determined by written questionnaires and telephone interviews. Hospital records and death certificates were obtained if interim hospitalization or death had occurred. Results. The overall 30-year actuarial survival rate among survivors of the perioperative period was 74 percent, as compared with 85 percent among controls matched for age and sex. The perioperative mortality...

Repair of transposition of the great arteries in patients with intact ventricular septum and fixed left ventricular outflow tract obstruction has been restricted to atrial baffle procedures, with or without attempts to relieve or bypass the left ventricular outflow obstruction. However, the suboptimal results of these procedures, coupled with excellent functional results with the arterial switch operation in patients without obstruction, has made anatomic correction the goal in repairing these anomalies. We report a technique for the anatomic correction of transposition of the great arteries, intact ventricular septum, and fixed left ventricular outflow tract obstruction. Its consideration in these difficult cases is advocated.

Core and valence level spectra for selected tetraosmium compounds have been investigated by means of X-ray photoelectron spectroscopy (XPS). Investigated compounds are Os carbonyl clusters with the following formulas: [H 3 Os 4 (CO) 12 ] − (PPN) + , [H 2 Os 4 (CO) 12 I] − (PPN) − , [H 4 Os 4 (CO) 12 ] and [H 3 Os 4 (CO) 12 I]. Observed binding energy (b.e.) trends are commented on the basis of a quantitative empirical model originally proposed by Feltham and Brant, modified by us to account for cluster compounds of Os. The model describes observed b.e.s in terms of parameter values for specific atoms or atomic groups and takes into account the formal charge on each metal atom. The application of parameter values to reported compounds reproduces observed b.e. within the experimental uncertainty of ±0.2 eV.

An 83-year-old man, 9 years after repair of a postinfarction aneurysm of the left ventricle, developed fever, anemia, and congestive heart failure. Extensive evaluation of the gastrointestinal tract revealed no evidence of ulcer disease. While in the hospital, he developed massive hematemesis and melena and died 2 days later. At autopsy, a communication existed between a left ventricular pseudoaneurysm and the stomach to form a cardiogastric fistula. Infection of the left ventricular pseudoaneurysm may have precipitated the gastric perforation. This represents an extremely rare late complication of aneurysmectomy procedures and, to our knowledge, is the first case to be reported in the absence of primary gastrointestinal pathology.

The carbon-capped triangular trimetal cluster with the composition FeCo 2 (CO) 9 (CHR) exists in solution as an equilibrium mixture of two tautomers: HFeCo 2 (CO) 9 (CR) [I] = FeCo 2 (CO) 9 (HCR) [II]; R = Me, Ph, 3-PhC 6 H 4 , 3-t-BuC 6 H 4 , β-naphthyl, and 2,3-Me 2 C 6 H 3 . The equilibrium constants have been measured by NMR and/or IR methods, while the rate constants for the interconversion of I and II have been obtained by line-shape analysis of the NMR data. Although the energy difference between tautomers is small, an analysis of the spectroscopic data for both species shows that the bonding of both the hydrocarbyl fragment and the metal carbonyl fragment change substantially, but in a complementary manner, in going from I to II. The data demonstrate that the substituent on the carbyne carbon can perturb the equilibrium via a steric effect; however, the importance of electronic effects on the equilibrium constant is evident in the comparison of the mixed-metal system with other isoelectronic clusters

Of 500 patients who had a modified Fontan operation at this institution between 1973 and 1987, 54 (33 boys and 21 girls) were less than 4 years old. This retrospective study related preoperative clinical and hemodynamic data to subsequent survival. Twenty patients less than 4 years old had tricuspid atresia, 13 had double inlet ventricle and 21 had other complex heart defects. There were 14 early deaths (less than 30 days after operation) and 6 late deaths. Multivariate analysis of survival for the entire group of 500 patients revealed the following factors to be significantly associated with poorer survival: absence of tricuspid atresia (p = 0.011), asplenia (p less than 0.001), age less than 4 years at operation (p = 0.042), atrioventricular valve dysfunction (p = 0.017), early calendar year of operation (p less than 0.001) and the presence of either one or more of the following: left ventricular ejection fraction less than 60%, mean pulmonary artery pressure greater than 15 mm Hg and pulmonary arteriolar resistance greater than 4 U.m2 (p less than 0.001). On the basis of this study of 500 patients, age less than 4 years at operation appears to be an independent risk factor for poorer survival after the modified Fontan operation.