Fractional Wigner Crystal in the Helical Luttinger Liquid.

The properties of the strongly interacting edge states of two dimensional topological insulators in the presence of two-particle backscattering are investigated. We find an anomalous behavior of the density-density correlation functions, which show oscillations that are neither of Friedel nor of Wigner type: they, instead, represent a Wigner crystal of fermions of fractional charge e/2, with e the electron charge. By studying the Fermi operator, we demonstrate that the state characterized by such fractional oscillations still bears the signatures of spin-momentum locking. Finally, we compare the spin-spin correlation functions and the density-density correlation functions to argue that the fractional Wigner crystal is characterized by a nontrivial spin texture.

[Late thrombosis of a drug-eluting coronary stent after antiplatelet therapy discontinuation]. / Thrombose tardive d'une endoprothèse coronaire pharmacoactive après arrêt des agents antiplaquettaires.

We reported the late thrombosis of a drug-eluting coronary stent related to discontinuation of antiplatelet therapy for venous surgery of the right leg more than half and a year after its implantation. After this acute myocardial infarction, a cardiac assistance device has to be used as a bridge to transplantation because of end stage ischaemic cardiopathy. Antiplatelet therapy management must be revisited for eluting stents, which can clot lately after its implantation.

Use of inhaled nitric oxide for emergency Cesarean section in a woman with unexpected primary pulmonary hypertension.

PURPOSE: Use of inhaled nitric oxide (iNO) could be of importance in emergency cases of primary pulmonary hypertension (PPH) in pregnant patients during labour and delivery. iNO acts as a selective pulmonary bed vasodilator avoiding systemic hemodynamic effects due to its ease of administration. Pulmonary bed vasodilation improves right ventricular function directly and left ventricular function indirectly. CLINICAL FEATURES: We report the case of a pregnant patient with unexpected PPH in whom an emergency Cesarean section (CS) had to be performed. PPH was diagnosed on admission as she arrived in active labour at 34 weeks gestational age. An emergency CS was performed under epidural anesthesia for breech presentation . All along labour, delivery and the first 24 hr, iNO was administered via a noninvasive ventilation device. CS was uneventful. A severe pulmonary hypertensive crisis was observed 12 hr after delivery and resolved with an increase of iNO concentration and administration of isoprenalin. The patient and baby returned home on day ten. CONCLUSION: The ease of administration of iNO allowed the optimal control of pulmonary arterial hypertension. No interaction with epidural anesthesia was observed. Use of iNO can improve the management of urgent CS in women with unexpected PPH.

Cold blood cardioplegia and warm cardioplegic reperfusion in heart transplantation.

The major cause of early death after heart transplantation is graft failure. In 99 consecutive heart transplantations two protocols of myocardial protection were employed. In group 1 (n = 38) initial cold crystalloid cardioplegia combined with cold saline storage and peroperative surface cooling was used. In group 2 (n = 61) cold crystalloid cardioplegia was injected initially and cold blood cardioplegia (Buckberg) was infused every 30 min as soon as the graft arrived in the operating room. No surface cooling was used. Warm blood cardioplegic reperfusion was administered before removal of the aortic clamp. There were 8 early (within 30 days) deaths in group 1 and 6 in group 2 patients. In group 1 there were 5 cardiac deaths against 3 in group 2. Mean ischemic time was 153 +/- 37 min in group 1 and 158 +/- 51 min (p greater than 0.05) in group 2. The post-transplantation need for catecholamines was ten times higher in group 1 patients than in group 2. The first endomyocardial biopsy (after 1 week) showed cytologic lesions compatible with ischemia in 40% of group 1 and only 9% in group 2 patients. We conclude from this initial experience that intermittent cold blood cardioplegia and warm blood cardioplegic reperfusion are useful in heart transplantation in restoring the damage suffered by the graft during brain death and graft storage.

Chronic traumatic aneurysms of the descending thoracic aorta (19 cases).

From 1973 through 1983, 19 cases of chronic traumatic aneurysms (CTA) were observed. Initial trauma was well documented in every case. Patients mean age at time of trauma was 22; mean age at time of surgery was 34. Sixty per cent of patients had no apparent thoracic injury at time of trauma. Ninety-five per cent had associated injuries. Ten/nineteen were asymptomatic. Eighteen were operated on. Rupture was complete in 11, partial in 7. One of the partial ruptures was a simple scar on the aorta. Eighteen were located at the site of the aortic isthmus, one was at level T8-T9. Seventeen had a prosthetic dacron graft sutured from inside the aneurysm. The case where a simple scar was found had a dacron wrapping. Spinal cord protection was used in all cases except in one who was already paraplegic preoperatively. Various shunts were used in 12 cases; 1 patient in the by-pass group had paraplegia. CTA is not a benign disease and all cases, even asymptomatic, should be operated on with a very low risk of mortality (0/18). Occurrence of paraplegia still remains a possible complication although the risk of spinal cord ischemia seems lower than in arteriosclerotic dissecting aneurysms. We favour the "old" technique of temporary dacron shunt graft in CTA for simplicity and easy assessment of function ot the shunt.

[Existence of asymptomatic changes in left ventricular function in the diabetic. Noninvasive study]. / Existence d'altérations asymptomatiques de la fonction ventriculaire gauche chez le diabétique. Etude non invasive.

49 diabetics (D) (26 IDD and 23 NIDD) were compared to 32 controls (C). Absence of ischemic cardiopathy (IC) was confirmed by routine investigations and noninvasive cardiovascular techniques, including an exercise ECG using 12 leads and a thallium 201 scintigraphy. Our results show: a) a prolonged mean isovolumetric relaxation time (IVRT) as studied by the M mode echocardiography and phonomechanography: D = 0,10 sec +/- 0,04; C = 0,05 sec +/- 0,02; p less than 0,0001; b) a reduced mean EF slope: D = 97,48 +/- 37,08 mm / sec; C = 125,68 +/- 34,35; p less than 0,005; c) a high mean Weissler index (ratio of PEP to LVET): D = 40 +/- 0,08; C = 33 +/- 0,05; p less than 0,01. IVRT and EF slope abnormalities are related to increased myocardial stiffness and impaired LV compliance. In the absence of changes in preload and afterload, the high Weissler index reflects impaired contractility of the myocardium. These abnormalities are related neither to the duration of diabetes nor to the presence or severity of the complications. With the M mode echocardiography, mean diastolic and systolic thickness of the septum is greater in D with retinopathy than in C (p less than 0,005 and p less than 0,03 respectively); mean diastolic and systolic thickness of the posterior wall is greater in NIDD than in C (p less than 0,001 and p less than 0,025). We conclude that there is evidence of left ventricular functional abnormalities specific to diabetes and unrelated to IC and hypertension. Our findings support the hypothesis that they may be due to metabolic disorders and/or myocardial microangiopathy.

Experience with 813 aortic or mitral valve replacements with the Carpentier-Edwards bioprosthesis: Five year results.

813 patients underwent aortic (AVR) or mitral valve replacement using the Carpentier-Edwards bioprosthesis from 1976 to 1983. Operative mortality was 5.49% for AVR and 4.59% for MVR. Late mortality and complications were classified using criteria described by the Stanford Group. Actuarial survival at 5 years was 87.9% +/- 2.7% for AVR and 91.1% +/- 1.4% in MVR. Thromboembolism occurred at low rates of 0.48% pt yr for AVR and 0.90% pt yr for MVR. 98.2% +/- 0.90% of AVR and 96.9% +/- 1.3% of MVR pts were free from thromboembolism at 5 years. The low incidence of thromboembolism during the early postoperative period played a role in the low rates observed in the complete study. There was no valve thrombosis. Anticoagulation with warfarin was used in 35% AVR and 75% MVR with rates of bleeding complications of 1.20% pt yr and 1.10% pt yr. Overall valve failure rate was 2.04% pt yr at 5 years for AVR and 1.55% pt yr for MVR. Rates of reoperation for tissue failure remained low (0.24% pt yr for AVR and 0.32% pt yr for MVR). The advantage of a low rate of thromboembolism was not outweighed by the specific problems of bioprosthesis at 5 years.

[Sodium nitroprusside and coronary surgery]. / Nitroprussiate de soude et chirurgie coronaire.

The anti-hypertensive properties of sodium nitroprusside have been tested in 20 patients undergoing coronary arterial surgery. Were measured the arterial pressure, heart rate, mean right atrial pressure and mean left atrial pressure. The cardiac output, systemic vascular resistance and left ventricular stroke work index were deduced. A dose of 0.8 to 3 micrograms . kg-1 . min-1 sodium nitroprusside was given at the start of surgery, and immediately afterwards. The results showed a decrease of the systemic vascular resistance, a significant drop of arterial pressure, and a significant increase of heart rate as well as a tendency for the cardiac output to fall, probably because of insufficient vascular filing. When the mean left atrial pressure was kept at 14.8 +/- 3 mmHg (1.97 +/- 0.40 kPa), and left ventricular stroke work index fell, whilst cardiac output increased. Sodium nitroprusside seemed to be useful in coronary arterial surgery if used with care.

[Value of vasodilators in decreasing the afterload during infrarenal abdominal aorta cross-clamping]. / Intérêt des vasodilatateurs pour diminuer la post-charge au cours du clampage aorto-abdominal sous-rénal.

Adverse effects of aortic crossclamping (A. C. C.) have been shown by a retrospective study and a literature review. A. C. C. results in increased afterload with ensuing left ventricular function alteration and low cardiac index (C. I.). 15 P. T. S. sustaining an operation with A. C. C. below the renal arteries were studied. A Swan-Ganz catheter was positioned with recording of pressures, including radial artery pressure and repeated cardiac output determinations. Prior to A. C. C., vascular filling and nitroprusside (N. P.) infusion improved hemodynamic conditions. Increase of C. I. (1.8 to 2.8 l/mm-1/m2) was observed with important decrease in peripheral vascular resistance (from 2,346 to 1,425 dyne/s-1/cm-5), pulmonary capillary pressure was lowered slightly and heart rate as well as mean arterial pressure remained stable. During A. C. C., rate of N. P. infusion was increased to maintain stable arterial pressure. Hemodynamic improvement observed prior to A. C. C. was maintained.

[Problems encountered by the anesthetist-intensive care specialist during aorto-coronary bypass surgery]. / Problèmes posés a l'anesthésiste-réanimateur par la chirurgie du pontage aorto-coronaire.

The authors analysed a series of 400 aorto-coronary bypasses performed between 1970 and April 1978. A notable improvement in the statistics was seen during the second period between 1976 and April 1978. During this period, 248 patients were operated upon with a mortality of 4 per cent. The progress made was in large part attributed to improved preoperative assessment, in particular a complete ventricular assessment, improved peroperative myocardial protection and the use of the intra-aortic counter-pressure balloon and of sodium nitroprussiate.