New directions in the analysis of buried interfaces for device technology by hard X-ray photoemission.

Photoelectron spectroscopy is a characterization technique which plays a key role in device technology, a field requiring, very often, a reliable and reproducible analysis of buried, critical interfaces. The recent advent of laboratory hard X-ray spectrometers opens new perspectives toward routine studies of technologically-relevant samples for the qualification of processes and materials. In this review, the status of hard X-ray photoelectron spectroscopy (HAXPES) implemented with chromium Kα excitation (5.414 keV) and applied to technological research in nanoelectronics is presented. After an account of the role of synchrotron HAXPES and the specific effects to care about at the practical level, different aspects are developed, first for illustrating the benefits of the technique through specific application cases in the field of resistive memories and power transistors. Then, we provide a status update on quantification in HAXPES, both from core-level intensities and inelastic background analysis. Finally, we present preliminary results in a novel analytical field, operando HAXPES, where a prototypical device is operated in situ during the laboratory HAXPES experiment, opening up the possibility of unravelling the mechanisms occurring at buried interfaces and governing device operation.

[Undifferentiated sarcoma: usefulness of multimodality cardiac imaging in characterizing a rare intracardiac mass]. / Sarcome cardiaque indifférencié : intérêt de l'imagerie multimodale dans la caractérisation d'une masse intracardiaque.

We report the case of a man presenting with a Pierre Marie-Bamberger syndrome. This paraneoplastic syndrome revealed an undifferentiated intracardiac sarcoma. This case emphasizes the need for multimodality imaging to characterize intracardiac tumor.

A comparison of low vs conventional-dose heparin for minimal cardiopulmonary bypass in coronary artery bypass grafting surgery.

The biocompatibility of minimal extracorporeal circuits has improved; however, anticoagulation is still required. We compared standard high-dose anticoagulation with a low-dose heparin regimen in a retrospective study of patients who underwent coronary bypass surgery using minimal cardiopulmonary bypass. One hundred patients who received 300 IU.kg(-1) heparin were compared with 68 patients who received heparin according to an individually adjusted activated coagulation time target of 300 s, resulting in a mean (SD) heparin dose of 145 (30) IU.kg(-1) . There were no thromboembolic events in either group; however, patients in the low-dose group had lower 24-hour mean (SD) postoperative blood loss than the conventional group (545 (61) vs 680 (88) ml, p=0.001) and a reduced rate of transfusion of allogeneic blood (15% patients transfused vs 32%, p=0.01). An individually tailored low-dose heparin regimen for minimal cardiopulmonary bypass is safe and may be associated with reduced bleeding and lower transfusion requirements.

[Cardiac surgery without transfusion in 2005]. / Chirurgie cardiaque sans transfusion en 2005. A propos d'une série de 200 témoins de Jehovah opérés.

PURPOSE: Between January 1991 and October 2003, 200 Jehovah Witnesses adult patients underwent elective cardiac surgery. To asses the impact on continuing progress of blood saving protocols and the increasing operative risk of patients proposed to surgery, we have re-assessed our results in this specific population. METHODOLOGY: Files of the first 100 patients operated upon between 1991 and 1998 were reviewed, and compared to the following 100 ones treated between 1998 to today. All patients were scored using the Euroscore model. RESULTS: In the latest series, patients are older (68 vs 51) and 13% underwent an iterative procedure, although there was none in the first series. Three deaths occurred after one month at the beginning of our experience, only one in the latest series. Operative risk factors had distinctly deteriorated, with more redux, and ejection fraction lower than 35%. Major progress to maintain morbi-mortality stability were multifactorial: preoperative erythropoietin in order to reach an haemoglobin minimal value of 14 g/dL, Cornell University protocol, mini-ECC, warm blood cardioplegia, ultra-early extubation. CONCLUSION: Cardiac surgery without transfusion can be realised with an equivalent risk to that of classical surgery, despite an operative risk aggravation, due to the association of recent conservative techniques.

[Treatment of aorto-coronary saphenous vein bypass lesions: pros and cons of angioplasty]. / Traitement des lésions des pontages aortocoronaires veineux saphènes: pour ou contre l'angioplastie?

Heart patients who have undergone a coronary bypass may present with renewed myocardial ischemia, often connected with bypass dysfunction. The saphenous bypass is the most frequently implicated, and palliative revascularization may be envisaged, either by further bypass surgery, or by angioplasty. The latter approach has been developed since the beginning of the 1980s, and since that time there has been considerable technical and pharmacological progress in performing this type of graft. However the indications for angioplasty and its comparison with reoperation remain controversial. In the present study, it therefore seemed pertinent to include the respective opinions of two experts in the field of angioplasty and coronary bypass surgery.

[Aortic valve myxoma. Conservative valvular surgery]. / Myxome de la valve aortique. Chirurgie de conservation valvulaire.

The authors report a case of aortic valve myxoma discovered in a 35 years-old patient who suffered a transient ischemic attack. At operation a helicoidal gelatinous mass was found attached to the ventricular side of the right coronary cusp of the aortic valve by a pedicle. Through a mini-sternotomy approach the mass was excised and the cusp was repaired. Recovery was uneventful.

Retrocaval passage of coronary bypass grafts to the inferior left ventricle wall.

Revascularization of the inferior side of the left ventricle is performed most often with aortocoronary free grafts. This article describes a technical improvement for anatomical fit and gain of length of these grafts by directing them to the right side of the heart after a passage behind the inferior vena cava.

Aortic valve myxoma.

The authors report a case of aortic valve myxoma discovered in a 34-year-old patient who had suffered a transient ischemic attack. At operation, a heliocoidal gelatinous mass was found attached to the ventricular side of the right coronary cusp of the aortic valve via a pedicle. Through a ministernotomy approach the mass was excised and the cusp was repaired. Recovery was uneventful.

Does bilateral internal thoracic artery grafting increase surgical risk in diabetic patients?

BACKGROUND: The purpose of this study was to determine whether, with appropriate techniques, diabetic patients could benefit from the advantages of double internal thoracic artery (ITA) coronary bypass without an increased hospital risk. METHODS: Between January 1990 and December 1996, 207 consecutive diabetic patients underwent coronary artery bypass graft operations. In 74 patients both arteries (bilateral ITA group) were used, whereas 133 patients received one ITA and vein grafts or vein grafts alone (nonbilateral group). Patients in the bilateral ITA group were younger (p<0.0001), predominantly male (p<0.0001), and were operated on more electively. The internal thoracic arteries were harvested by skeletonization without electrocautery, and strict glycemic control was pursued. RESULTS: No death was observed in the bilateral ITA group, whereas 7 patients died in the nonbilateral ITA group (p<0.05). Deep sternal wound infection was observed in 2 patients in the nonbilateral ITA group (1.5%) and in none of the bilateral ITA group (p = NS). There was no significant difference in the morbidity rate between the two groups except for greater blood losses in the bilateral ITA group. CONCLUSION: Double ITA coronary revascularization in young diabetic patients was performed without increased morbidity and mortality. The low rate of sternal wound infections may be related to ITA harvesting by a skeletonization technique, but larger studies are required to confirm these data.

[Coronary revascularization by arterial bypasses: advantages, disadvantages]. / La revascularisation coronaire par pontages artériels: advantages, inconvénients.

Coronary vein grafts are frequently become occluded or develop atherosclerotic lesions in the long-term. In contrast, the internal mammary artery has a very satisfactory long-term patency rate. The use of an internal mammary artery on the LAD consequently increases the benefit of coronary surgery. The benefit of using 2 internal mammary arteries or other arterial grafts for coronary artery bypass surgery is more controversial. The advantages and disadvantages of the various coronary artery grafts are reported together with the clinical experience of several teams in this area. Coronary artery surgery should be reserved to patients with a good general condition, who are likely to benefit from this type of revascularization. The right internal mammary artery is unsuitable for revascularization of the right coronary network and the two internal mammary arteries must be used to revascularize the left coronary network, in order to obtain a good result. However, surgeons must be aware of the limitations of coronary artery surgery and these techniques should be used cautiously.

Mechanical circulatory support towards the permanent implantation.

Experience on wearable LVAS Novacor support accumulated since the first implantation in March 1993, includes in November 1995, seven cases (six male, one female, mean age 34) of cardiogenic shock, unresponsive to optimal medical management referred for urgent transplantation. Post-implantation period was free of any major incident in all but one, allowing transplantation in five, on an elective basis, and prolongation of the waiting period, at home in two. This experience suggests that a major breakthrough in the technology of mechanical support has been achieved: patients awaiting transplantation can be discharged home, which is both the result and an contributing factor of a satisfactory quality of life. This improvement allows speculations on coming studies on permanent implantation of the wearable LVAS Novacor, as an alternative therapy to cardiac transplantation.

The gastrointestinal tract: an underestimated organ as demonstrated in an experimental LVAD pig model.

BACKGROUND: Although hemodynamic stability and renal function are important and are monitored closely in patients with implanted left ventricular assist devices (LVAD), the gastrointestinal tract may be underestimated in the early postoperative period with regard to adequate perfusion. We investigated renal, intestinal, and whole body metabolic changes in response to variations in LVAD flow and inspired oxygen concentration (FiO2). METHODS: Left ventricular assist devices were implanted in 10 adult pigs (weight, 55 +/- 1.76 kg). Renal vein (RV), superior mesenteric vein (SMV), and pulmonary artery (PA) blood oxygen saturation and lactate concentration were measured and used as tissue perfusion markers. These measurements were made at baseline and after changes in LVAD flow or FiO2. RESULTS: Oxygen saturation in the PA, SMV, and RV decreased significantly after a reduction in LVAD flow (P < 0.05), with a greater reduction in the SMV than in the PA and RV (p < 0.05 at LVAD flow 3.5L/min; p < 0.01 at LVAD flow 2.0 and 1.0 L/min). The lactate concentration in the PA and SMV increased significantly (p < 0.01) with decreased flow, with a greater increase in the SMV than in the PA (p< 0.05), whereas it remained unchanged in the RV. Oxygen saturation in the PA, SMV, and RV decreased significantly after a reduction in FiO2 (p < 0.05). Lactate concentration in the PA, SMV, and RV increased significantly at FiO2 of 0.10 (p < 0.05). Lactate concentration in the PA and SMV was significantly higher than that in the RV at Fi)2 of 0.10 (p < 0.01). CONCLUSIONS: The results show that the gastrointestinal tract is at high risk during low perfusion or low FiO2, whereas the kidneys' metabolic function appears to be less disturbed. In clinical practice, this emphasizes the need to ensure adequate blood flow and respiratory function, especially after extubation, in patients with implanted LVAD. This might avoid intestinal ischemia and subsequent endotoxemia. Gastrointestinal tonometry may help in the assessment of intestinal perfusion.

[Wearable mechanical ventricular support]. / L'assistance mécanique ventriculaire portable.

Progressive technological developments have permitted clinical use of the wearable Baxter-Novacor left ventricular assist system. The system allows total bypass of the left ventricular function, and recovery of an adequate circulation in patients about in cardiogenic shock. Since the first clinical use, in March 1993, six patients about to die have been supported with a cardiac transplantation. This experience suggests that an acceptable answer to the problem of organ shortage is non available.

[Orthotopic cardiac transplantation with caval anastomosis: a comparative randomized study with standard procedure in 81 cases]. / Transplantation cardiaque orthotopique avec anastomoses caves: étude randomisée comparative avec la technique standard sur 81 procédures.

Complete resection of the right atrium with conservation of a strip of left atrium around the 4 pulmonary veins followed by direct anastomosis on the vena cava has recently been proposed as an alternative to the standard orthotopic cardiac transplantation described by Shumway and Lower. In order to determine whether this "anatomical" transplantation should now be considered to be the procedure of choice, a prospective randomised study was undertaken in 1991 including 78 patients undergoing 81 cardiac transplantations by one of the two techniques: gr. I: classical transplantation (n = 40), gr. II: "anatomical" transplantation (n = 41). The groups were comparable in age, sex, weight, nature of the underlying cardiac disease and clinical status at the time of transplantation. Similarly, the parameters of the donors were comparable with respect to age, sex, weight and dosage of inotropic drugs at the time of explantation. All patients came of cardiopulmonary bypass with comparable ischaemia time of the graft (gr. I: 136 +/- 46 min; gr. II: 138 +/- 51 min). Immediate return to sinus rhythm occurred in 20 cases in gr. I and 36 cases in gr. II. Atrial arrhythmia persisted in 5 cases in gr. I but in no cases of gr. II. These differences were very significant (p < 0.001). There were 13 early deaths in gr. I and 8 in gr. II. Doppler echocardiography was performed two to three months after transplantation. The right atrial surface was significantly decreased in gr. II (18 +/- 4.7 cm2) compared with gr. I (24 +/- 7 cm2): the same difference was observed for the left atrium (gr. I: 24 +/- 4.5 cm2; gr. II: 20 +/- 5 cm2), p = 0.001. Tricuspid regurgitation was observed in 82% of patients in gr. I compared with 57% in gr. II (p < 0.005). Exercise stress tests during the same period showed no difference in peak oxygen consumption between the groups. Holter ECG monitoring led to permanent pacing in 2 patients of gr. I (5%). The technical simplicity and reduction of postoperative morbidity, especially with respect to arrhythmias, suggest an advantage with the "anatomical" technique considering the lack of surgical complications.

Mechanical bridge to transplantation: when is too early? When is too late?

BACKGROUND: Optimal timing of implantation of a mechanical circulatory support system in the treatment of acute cardiogenic shock is still unsettled. The issue has been addressed in a retrospective analysis of a group of 98 patients in cardiogenic shock refractory to medical therapy who were candidates for cardiac transplantation, admitted from 1987 to 1994. METHODS: The treatment included reinforced inotropic support by addition of phosphodiesterase inhibitors to sympathomimetic agents. The patients who did not improve were immediately brought to the operating room for mechanical circulatory support system implantation. RESULTS: The overall survival in the group of 28 patients selected for mechanical bridge is 50%. No predictive factors of death or multiorgan failure while on the device could be identified, suggesting a lack of contraindications to mechanical circulatory support system implantation. CONCLUSIONS: The high death rate in patients maintained on medical therapy because of initial improvement as they are awaiting transplantation suggests the benefit of a rapid semielective implantation of an intracorporeal device.

Right ventricular late filling termination time and its relation to interstitial collagen content in early transplanted heart: a color M-mode Doppler digital analysis.

BACKGROUND: Histologic changes in cardiac allografts resulting from fibrosis or acute rejection can modify ventricular diastolic function and ventricular inflow characteristics. These abnormalities may be detected by color M-mode Doppler echocardiography which has been shown to be sensitive in assessing ventricular diastolic function. METHODS: Twelve cardiac allograft recipients were prospectively studied with serial color M-mode and single-gated Doppler echocardiography, as well as with endomyocardial biopsy, with a follow-up of approximately 10 weeks. The myocardial interstitial collagen content as evaluated by videodensitometry was compared with right and left ventricular late filling termination times measured in the absence of a severe episode of rejection. RESULTS: A positive and significant correlation was found between the collagen content and the corresponding right ventricular late filling termination time (r = 0.89, p < 0.0001), but no correlation was found with the left ventricular late filling termination time. Moreover, variations in collagen content and variations in right ventricular late filling termination time were also highly correlated (r = 0.91, p < 0.0001). In allograft recipients who had episodes of rejection of grade 3A or greater, both right and left ventricular late filling termination times were significantly increased during rejection. CONCLUSIONS: Measurements of right ventricular late filling termination time by color M-mode Doppler echocardiography performed in the absence of acute rejection can be use to monitor the evolution of interstitial collagen content in cardiac allografts. The early detection of abnormally prolonged late filling termination time could be followed by endomyocardial biopsy to confirm the histologic changes.

[Cardiac transplantation; results after 5 years]. / La transplantation cardiaque; résultats après 5 ans.

After cardiac transplantation, long-term results were assessed in a group of 46 patients who survived more than 5 years after surgery. They were the survivors (50%) of a group of 92 patients who underwent transplantation before January 1990. On January 1995, mean follow-up was 82 +/- 14 months. Quality of life was estimated satisfactory (mean score 8.4 +/- 2); 60% of the patients were active; 89% were class NYHA I or II. Nevertheless, several problems have been identified: rise in body weight for all, over 10 kg in 31%; hypertension, renal failure, considered to be severe (serum creatinine > 250 micrograms/l) in 26%, diabetes in 13%, osteoarthropathy in 33%, cancer in 6%, and, above all, chronic alteration of the coronary arterial bed in 53% of the patients. These problems reflect the immunological conflict and complications of immuno-suppression.

A right ventricular hemopump restores right ventricular function with pulmonary artery banding.

We investigated the ability of the Hemopump to support the right ventricle during acute, partial, pulmonary artery obstruction. In 6 pigs, a 14 Fr size Hemopump was placed through the pulmonary artery into the right ventricle. Control measurements were made. A band around the pulmonary artery proximal to the outflow port of the Hemopump was tightened, and measurements were repeated with the Hemopump at minimum and then maximum speed. With banding, right ventricular stroke volume and output decreased (43 [SD, 7] to 28 [SD, 8] ml, p < 0.001; 4.9 [SD, 0.8] to 3.7 [SD, 1.0] L/min, p < 0.01 respectively), but they were restored with the Hemopump (38 [SD, 5] ml and 4.5 [SD, 0.6] L/min; both p = NS vs control). Increases in right ventricular peak systolic (28 [SD, 10] to 42 [SD, 17] mm Hg; p < 0.01) and end-diastolic pressure (2 [SD, 1] to 12 [SD, 6] mm Hg; p < 0.02) were reversed by the Hemopump (29 [SD, 8] and 4 [SD, 2] mm Hg; both p = NS vs control). Right ventricular pressure rate product almost doubled with banding (3,199 [SD, 1,252] to 5,962 [SD, 2,796] mm Hg; p < 0.01), but it decreased with the Hemopump (3,368 [SD, 767] mm Hg; p = NS vs control). With acute partial pulmonary artery banding, a right ventricular Hemopump restores output from and offloads the right ventricle.

[Mechanical assistance of circulation. 42 cases]. / Assistance mécanique de la circulation. 42 observations.

OBJECTIVES: Mechanical circulatory support was proposed in patients in cardiogenic shock, as a bridge to cardiac transplantation or weaning. The aim of the present study is an analysis of the first 42 cases. METHODS: The 42 cases included 31 patients in cardiogenic shock unresponsive to medical therapy, good cardiac transplant candidates, and 11 patients unweanable off ventricular assist, or in shock in the intensive care unit. Results are evaluated in terms of transplantability and hospital survival. RESULTS: Overall success rate is 67%, ranging from 25% in previously transplanted patients to 46% following acute myocardial infarction and 57% in cardiomyopathy. Age and learning curve played a significative role. CONCLUSION: These data suggest that mechanical support improves survival in patients in cardiogenic shock. Earlier implantation should improve the patient outcome.