Remotely-pumped network-embedded self-tuning transmitter for 80-Gb/s conventional hybrid TDM/WDM PON with 256-split.

We present a colorless network-embedded self-tuning transmitter assisted by a remotely pumped erbium-doped double-pass amplifier located at the remote node for a conventional hybrid stacked-WDM/TDM-PON. The scheme provides up to 256-split PON with 80-Gb/s aggregate upstream capacity obtained with RSOA direct modulation at 2.5 Gb/s.

Efficient modulation cancellation using reflective SOAs.

Modulation cancellation and signal inversion are demonstrated within reflective semiconductor optical amplifiers. The effect is necessary to implement colorless optical network units for network end-users, where downstream signals need to be erased in order to reuse the carrier for upstream transmission. The results presented here indicate that reflective semiconductor optical amplifiers possess the perfect high-speed all-optical gain saturation characteristics to completely cancel the downstream modulation at microwatt optical power levels and are thus the prime candidate to be constituents of future optical network units. Theoretical considerations are supported by experiments that show the cancellation of signals with a 6 dB extinction ratio at 2.5 Gbit/s.

Linear semiconductor optical amplifiers for amplification of advanced modulation formats.

The capability of semiconductor optical amplifiers (SOA) to amplify advanced optical modulation format signals is investigated. The input power dynamic range is studied and especially the impact of the SOA alpha factor is addressed. Our results show that the advantage of a lower alpha-factor SOA decreases for higher-order modulation formats. Experiments at 20 GBd BPSK, QPSK and 16QAM with two SOAs with different alpha factors are performed. Simulations for various modulation formats support the experimental findings.

Network-embedded self-tuning cavity for WDM-PON transmitter.

A network-embedded self-tuning cavity is proved in wavelength division multiplexed passive optical network transmission over 32 channels. The external source-less topology takes advantage of a reflective element at the remote node and a reflective semiconductor optical amplifier at the optical network unit to establish a distribution-fiber based cavity. The bit error rate performance of up to 5-km cavities is presented with two optical network units simultaneously operating and with downstream signal co presence. The experimental analysis at 1.25 Gb/s provides an evaluation of polarization dependences when exploiting low polarization dependent gain reflective semiconductor optical amplifiers with 25-km and 50-km standard single mode fiber transmission.

Quantum dot SOA input power dynamic range improvement for differential-phase encoded signals.

Experimentally we find a 10 dB input power dynamic range advantage for amplification of phase encoded signals with quantum dot SOA as compared to low-confinement bulk SOA. An analysis of amplitude and phase effects shows that this improvement can be attributed to the lower alpha-factor found in QD SOA.

Analysis of outcome after using high-risk criteria selection to surgery versus endovascular repair in the modern era of abdominal aortic aneurysm treatment.

INTRODUCTION: The concept of high-risk patients suggests that such patients will experience a higher rate of postoperative complications and worse short- and long-term outcomes, and should therefore benefit from the use of endovascular techniques for aortic abdominal aneurysm (AAA) repair. The primary goal of this study was to assess the relevance of the different high-risk criteria, defined by the French health agency Agence Française de Sécurité Sanitaire des Produits de Santé (AFSSAPS) in a single-centre continuous series. Secondary goals were to retrospectively compare the incidence of postoperative complications and short- and long-term survival in three groups of patients. MATERIALS AND METHODS: Between January 1999 and December 2006, details of all the patients undergoing elective surgery for AAA in our hospital were recorded into a prospective registry (n=626). Three groups were considered according to the level of risk and type of repair defined by the AFSSAPS: endovascular aortic aneurysm repair (EVAR) high-risk (HR) (at least one high-risk factor and EVAR, n=138), open HR (at least one high-risk factor and open repair, n=134) and open low-risk (LR) (no high-risk factors and open repair, n=344). None of the low-risk patients were treated using an endovascular approach. The demographics, preoperative risk factors, intra-, postoperative data and short- and long-term survival were compared between the groups. Interrelations among the set of high-risk criteria for mortality were calculated using multiple correspondence analysis (MCA). RESULTS: The distribution of high-risk criteria was similar in both high-risk groups, except for age, heart failure and hostile abdomen, which were significantly more frequent in EVAR HR. Operation time, blood loss and length of stay in an intensive care unit and hospital were significantly lower in the EVAR HR group. The 30-day mortality and survival rates at 5 years were 5.4 and 59.4% for EVAR HR, 3.7 and 70.4% for open HR and 2.3 and 83.7% for open LR, respectively, with no significant difference between the three groups for the mortality, but a significant higher survival at 5 years for the open LR versus both high-risk groups. CONCLUSION: The high-risk AFSSAPS criteria were not predictive of postoperative mortality and should not be used to determine the choice of treatment technique. Other criteria therefore need to be established to determine whether open or EVAR repair should be used.

[Cardiac papillary fibroelastoma, a rare valvular source of cerebral embolism: report of two cases]. / Le fibroélastome valvulaire, une cause cardiaque rare d'accident vasculaire cérébral: à propos de deux cas.

Cardiac papillary fibroelastomas are very rare and benign tumors, usually involving heart valves. They are sometimes asymptomatic. However, they become serious illnesses when associated with clinical events, as systemic embolism. Diagnosis is evoked by echocardiography and confirmed by histopathological examination. The only curative treatment consists of the excision of the tumor under cardiopulmonary bypass. This approach is safe and prevents the risk of embolism recurrence. We report the cases of two patients suffering from acute cerebral embolism. Transthoracic and transoesophageal echocardiography detected tumors of the mitral and aortic valve in the first and second patients, respectively. Preserving the valve integrity, both masses were surgically excised and pathological findings confirmed the diagnosis. As surgical management is curative, we believe that these lesions should be always removed.

[True isolated atherosclerotic aneurysm of the axillary artery]. / Anévrisme vrai isolé d'origine athéromateuse de l'artère axillaire.

The true atherosclerotic aneurysm of the axillary artery is a rare condition. It either presents as a pulsatile axillary mass or arterial emboli in the hand and fingers. We report the case of a 70-year-old man with a 5 cm aneurysm of the axillary artery presenting with embolic disease to the hand. Angiography is helpful and provides valuable preoperative anatomic details. Surgery remains the treatment of choice but endovascular treatment can also be considered.

Fatal cardiovascular complications in a patient with Ehlers-Danlos syndrome type IV and dextrocardia.

A report is presented of a 31 year female patient with Ehlers-Danlos syndrome type IV who presented a bilateral renal artery dissection and a hematoma of the ascending aorta simultaneously. She had had an uneventful delivery six months before. We also discovered a situs solitus with dextrocardia in this patient. These complications were managed conservatively. Unfortunately the patient died of a pulmonary infection and a multi-organ failure syndrome several days after her admission.

Endovascular treatment as first choice in chronic intestinal ischemia.

The purpose of this study was to define the place of endovascular treatment in chronic intestinal ischemia (CII). We report here a series of 19 consecutive patients treated with percutaneous angioplasty of the intestinal arteries. We excluded patients with acute ischemia, from the study. From January 1, 1989 to December 31, 2001, 19 patients with symptomatic CII were treated by endovascular techniques. This study group included 11 men and 8 women with a mean age of 59 years (range 30 to 90 years). The clinical presentation included postprandial pain in 16 patients, weight loss in 14 patients, with a mean weight loss of 7.4 kg (range 0 to 30 kg); and gastroparesis in 2 patients. Stenoses were significant in the single superior mesenteric artery (SMA) in 2 patients and in two arteries in 17 patients, including the celiac artery (CA) and SMA (n = 13), CA and inferior mesenteric artery (IMA) (n = 1), and SMA and IMA (n = 3). Balloon angioplasty was performed in only one of the arteries in each patient, 15 times in the SMA and 4 times in the CA. In 7 patients, angioplasty required stenting because of recoil (n = 5) or dissection (n = 1). In one patient the lesion was stented primarily, because of adjacent thrombus on the stenosis. Our results showed that initial treatment of CII can be endovascular. Focus on one artery only, seems to be reasonable and efficient in the short and long term.

[Four years followup of complicated Cockett syndrome treated by iliac vein endoprosthesis]. / Suivi à 4 ans des endoprothèses veineuses iliaques dans le syndrome de Cockett compliqué.

The purpose of this study was to check the long-term patency of the left common iliac vein endoprosthesis in Cockett syndrome and to confirm this appropriate etiological treatment in complicated cases. Three patients had respectively a pulmonary embolism, left common iliac vein occlusion with protein S deficiency, and venous claudication (Paget-von Schroetter syndrome) as complications of the Cockett syndrome. Treatment with endoprosthesis was performed. A mean follow-up of 48.6 months (31-61 months) revealed a clinical improvement without any recurrence of complications. The patency of the left common iliac vein flow was maintained. Indications on this treatment are being discussed.

[Cardiogenic shock complicating extensive infarction with ventricular septal defect. Circulatory assistance and heart transplantation]. / Choc cardiogénique sur infarctus étendu, compliqué d'une communication interventriculaire. Assistance circulatoire et greffe cardiaque.

A 47 year old man had a massive anterior myocardial infarction with cardiogenic shock with a left parasternal murmur. Coronary angiography showed occlusion of the left anterior descending artery for which angioplasty resulted in failure. There was antero-lateral-apical akinesia and a ventricular septal defect (VSD) with a left-right shunt (Qp/Qs = 1.54). Persistence and aggravation of haemodynamic instability led to intra-aortic balloon pumping with inotropic pharmacological support followed by biventricular assistance with a MEDOS device. Under transoesophageal echocardiographic monitoring, the outcome was marked over 7 days by the progressive increase in the shunt volume of the VSD, a decrease of drainage and injection flow, progressive increase in spontaneous contrast echos followed by the presence of fibrin in the cardiac chambers and canulae, the presence of thrombus in the external ventricles, blockage of the right external valve which only opened after increasing the degree of anticoagulation, and, finally, cardiac tamponade which required drainage before the patient's state improved. On the 8th day, the patient being stable with a normal neurological status, the availability of a donor heart led to the decision to transplant, which was carried out without complications. This case poses the problem of cardiac assist devices and their daily monitoring, and then that of cardiac transplantation in this indication.

Fracture-embolization of duromedics valve prosthesis and microscopic uncommon lesions.

We report a sudden leaflet fracture of a Duromedics mitral valve 6 years after implantation. The patient had cardiogenic shock and complained of asthenia, orthopnea, and tachycardia. Transesophageal echocardiography showed the lack of one leaflet of the prosthesis and regurgitation. An emergency mitral replacement was successfully performed. Angiographic computed tomography scan localized the sequestrum that embolized the common iliac arteries. Examination of the deficient prosthesis showed multiple lesions and, in particular, a subsurface lesion that may be characteristic of carbon pyrolytic valves.

Fracture embolization of a Tekna mitral prosthesis: case report.

The modified Duromedics-Tekna bileaflet pyrolitic carbon mechanical prosthesis was reintroduced by Baxter in 1990. This report details the first case of sudden leaflet fracture of a Tekna mitral valve five years after implantation, which was managed successfully by replacement with a St. Jude Medical mechanical prosthesis. The fracture had occurred transversely, with the fragments embolizing to the terminal aortic bifurcation and the left common femoral artery. These were localized by computed tomography and removed two days after valve replacement.

Cardiac pheochromocytoma.

Primary pheochromocytomas of the heart are extremely uncommon. In this report, we present the case of a patient with primary cardiac pheochromocytoma arising from the interatrial septum. Metaiodobenzylguanidine-scintigraphy was negative and diagnosis was confirmed by a positive octreotide scintiscan. The tumor was removed successfully using cardiopulmonary bypass.

[Long-term hemodynamic function of the transplanted heart]. / Fonction hémodynamique du coeur transplanté à long terme.

The aim of this study was to identify the long-term haemodynamic changes of the transplanted heart. Between 1987 and 1997, 136 patients required cardiac transplantation at Dijon hospital. During follow-up, 76 patients aged 51.2 +/- 9.46 years underwent catheter studies (12 women, 15.8%; and 64 men, 84.2%). Right and left heart catheterisation was performed at 3 months, 1, 2, 3 and 5 years after transplantation. Right heart catheterisation included measurement of mean pulmonary artery and pulmonary capillary pressures and pulmonary arteriolar resistances. During left heart catheterisation, cardiac output, mean aortic pressure, the ejection fraction, the dp/dt max of the left ventricular wall, systemic arterial resistances and left ventricular end diastolic pressures were measured. At each catheter study, the indexed myocardial mass, indexed end systolic and end diastolic left ventricular volumes, the mass/volume ratio, the residual serum cyclosporine concentrations and the serum creatinine were analysed. In addition, an endomyocardial biopsy was also performed. Initially raised, the mean pulmonary artery and pulmonary capillary pressures decrease from the 3rd month to the 2nd year. From the 3rd year onwards, they readjust to the upper limits of normal. The pulmonary artery resistances underwent the same changes. The left heart parameters remained constant over the period of follow-up but with a heart rate, mean aortic pressure and left ventricular end diastolic pressure higher than normal. The indexed myocardial mass was increased at all periods. The indexed left ventricular end systolic and diastolic volumes decreased with a M/V ratio which increased. Cyclosporine concentrations decreased whereas serum creatinine increased. The frequency of severe rejection and of coronary atherosclerosis was low. Significant correlations were observed between different parameters at different periods. In the long-term, the function of the transplanted heart is not normal in the strict sense of the term. The apparent normality is obtained by anti-hypertensive treatment. The transplanted heart adapts to the increase in cyclosporine-induced afterload by permanent myocardial hypertrophy, and increased diastolic pressure probably relates to diastolic dysfunction without noticeable intracardiac fibrosis.

Preoperative intraarterial thrombolysis before surgical revascularization for popliteal artery aneurysm with acute ischemia.

Because a popliteal artery aneurysm (PAA) generates emboli that progressively deteriorate the distal arterial network, they can constitute limb-threatening lesions. In 20 to 40% of cases, discovery of PAA coincides with sudden occlusion and resulting acute ischemia. In 40 to 60% of these patients, surgical revascularization fails and amputation is required. The objective of this prospective study was to assess the value of intraarterial thrombolysis to restore distal runoff before surgical revascularization. Between January 1, 1992 and December 31, 1996, we treated 15 PAA causing acute ischemia in 15 male patients with a mean age of 66.7 years (range, 44 to 87 years). Diagnosis was documented by clinical examination and ultrasound imaging. Intraarterial thrombolysis was performed under arteriographic control through a multiperforated catheter inserted by the anterograde femoral route to the thrombus. After an initial bolus of 100,000 U of urokinase, 600,000 to 1,600,000 U was continuously infused over a period of 6 to 18 hr. Heparin sodium was administered throughout thrombolysis. Surgical revascularization was performed within 1 to 4 days (mean, 2 days) after thrombolysis by exclusion and bypass in 14 cases and percutaneous transluminal angioplasty with stenting in 1 case. The ensuing results showed that, if performed carefully, intraarterial thrombolysis can safely prepare patients presenting with occluded PAA with acute ischemia for surgical revascularization to restore distal runoff. We use this combined technique routinely in our department. Morbidity is low in comparison with the risks of amputation.