Performance comparison of Yb:YAG ceramics and crystal gain material in a large-area, high-energy, high average-power diode-pumped laser.

We compare for the first time the influence of different Yb:YAG gain media on the performance of a large-area, high average-power laser system with an output energy of up to 6 J. Monocrystalline slabs grown by a new technique without central growth defect are compared with ceramics. Small signal gain, maximum output energy and thermal lensing are compared for ceramic slabs with co-sintered amplified spontaneous emission (ASE) absorber cladding, monocrystalline slab with and without optically bonded ASE absorber cladding, and surface structured monocrystalline slabs. We show that these large monocrystals with optically bonded absorber cladding have similar performance to cladded ceramics, so far the only material for high-energy Yb:YAG lasers.

Lung Allocation Score System: First Italian Experience.

BACKGROUND: Lung transplantation is an established therapeutic option for patients with end-stage pulmonary disease. In May 2005, the lung allocation score (LAS) was introduced in the United States to maximize the benefit to the recipient population and reduce waiting list mortality. The LAS has been applied in a region of Italy since March 2016 on a provisional basis. The aims of the study were describing waiting list characteristics and short-term outcomes after lung transplantation before and after LAS introduction. METHODS: All the patients who received transplants between January 1, 2011, and March 15, 2017, were included in our retrospective study. The study population was divided into 2 cohorts (historical cohort and post-LAS cohort) and a comparison among the main perioperative data was performed. RESULTS: The historical cohort consisted of 415 patients on the waiting list with 91 deaths and 199 lung transplants; the post-LAS cohort consisted of 134 patients with 10 deaths on the waiting list and 51 transplants. Median waiting time and mortality on the list decreased from 223 to 106 days (P = .03) and from 11.2% to 7.5% (P > .05), respectively. The transplantation rate increased from 25% to 38% (P = .001) and the probability to receive a transplant in the first year in the post-LAS era increased significantly (P = .004). CONCLUSIONS: The results of the introduction of the LAS system in our region are encouraging and have not shown any adverse short-term effects. The regional coordination decided to prolong the experimental application of LAS in order to accumulate more data and to evaluate medium-term outcomes.

Mycotic aneurysm of the hepatic artery in pediatric liver transplantation: A case series and literature review.

Mycotic aneurysm of the hepatic artery (HA) is a rare, unpredictable, and potentially lethal complication of liver transplantation (LT). Pediatric LT is not exempt from it but the related literature is rather scanty. We present our experience with post-LT mycotic aneurysm of the HA in pediatric age, describing four cases occurred with a special focus on the possible risk factors for its development and a proposal for the management of high-risk recipients.

Use of the Oto lung donor score to analyze the 2010 donor pool of the Nord Italia Transplant program.

INTRODUCTION: The feasibility and utility of a lung donor score that has been recently proposed was tested among a pool of lung donors referred to the Nord Italia Transplant program (NITp) organ procurement organization. MATERIAL AND METHODS: Each lung donor was assigned an Oto score including, age, smoking history, chest X-ray, secretions and ratio of arterial oxygen tension to inspired oxygen fraction (PaO(2)/FiO(2)). Based on clinical compromise, each variable received a score between 0 and 3, except for PaO(2)/FiO(2), which was scored between 0 and 6 given its overall relevance. RESULTS: Throughout 2010, 201 multiorgan donors were initially considered to be potential lung donors. Among these, 59 (29.4%) eventually yielded 67 lung transplantations (named "Used group"). Among the 142 (70.6%) refused lungs, 28 were not used due to logistic or medical problems ("general exclusion" group, GE) and 114, because of poor lung function ("lung exclusion" group, LE). Median lung donor scores were 1 (range, 0 to 3), 4 (range, 2.5 to 6.5), and 7 (range, 5 to 9) in the Used, GE, and LE groups, respectively (one-way analysis of variance, P < .001). Some donors with Oto scores ≤7 worsened over time so that the score had significantly increased by the time of organ retrieval. Overall, subjects who died after lung transplantation were characterized by higher lung donor scores, (2 [1-4] versus 0.5 [0-3], P = .003). CONCLUSION: Our analysis suggested that the use of a donor score as a dynamic tool over the donation process was of great utility to describe and analyze a pool of lung donors.

Intestinal transplantation in children: the first successful Italian series.

The preliminary experience of the first Italian program of pediatric intestinal transplantation is presented herein. A multidisciplinary group with broad experience in pediatric solid organ transplantation started the program. Nine children with complications of chronic intestinal failure were listed for transplantation. One child died on the waiting list; one received an isolated liver transplantation; three isolated intestinal; three multivisceral; and one, a combined liver/intestine transplantation. There was no in-hospital mortality, and all children were weaned from parenteral nutrition. The recipient of the multivisceral graft died after 14 months for unknown causes. All other recipients are alive after a median follow-up of 13 months. Patient and graft actuarial survivals for recipients of intestinal grafts were 100% at 1 year and 75% at 2 years.

Lung transplantation with grafts from elderly donors: a single-center experience.

INTRODUCTION: Use of extended criteria donors is one of the strategies to face the scarcity of donors for lung transplantation. METHODS: Between November 2002 and May 2009, we performed 52 LTs in 50 recipients, 10 of whom (group A) received lungs from donors aged 55 years or older (median, 58.5; range, 56-66 years) for comparison with 28 patients (group B) transplanted with lungs from donors younger than 55 years (median, 25.5; range, 15-54 years). We excluded 9 children and 3 recipients of combined liver plus lung transplantations from the study. RESULTS: Recipient age, gender, and indications for transplantation did not differ significantly between the 2 groups. Neither were there significant differences in PaO2/FiO2 ratios before lung retrieval, or length of the ischemic time The first PaO2/FiO2 on arrival to the intensive care unit (ICU) and the median length of ICU stay were similar. All patients, except 2 who died in the operating theatre, were extubated between 3 and 216 hours after the transplantation. Hospital mortality was similar in both groups: 3 patients in group A and 2 in group B (P = .1). The median portions of the predicted 1-second forced expiratory volume (FEV1) at 6 months after transplantation did not differ in the 2 groups: 62.4% in group A versus 70% in group B (P = .85). CONCLUSION: Lung grafts from donors older than 55 years can be effectively used for transplantation, thus increasing the total organ pool.

Combined double lung-liver transplantation for cystic fibrosis without cardio-pulmonary by-pass.

Sequential bilateral single lung-liver transplantation (SBSL-LTx) is a therapeutic option for patients with end stage lung and liver disease (ESLLD) due to cystic fibrosis (CF). A few cases have been reported, all of them were performed with the use of cardio-pulmonary by-pass (CPB). We performed SBSL-LTx in three young men affected by CF. All the recipients had respiratory failure and portal hypertension with hypersplenism. Along with lung transplants, two patients received a whole liver graft and one an extended right graft from an in situ split liver. During transplantation neither CPB nor veno-venous by-pass (VVB) were employed. Immunosuppression was based on basiliximab, tacrolimus, steroids and azathioprine. The three recipients are alive with a median follow-up of 670 days (range 244-1,533). Combined SBSL-LTx is a complex but effective procedure for the treatment of ESLLD due to CF, not necessarily requiring the use of CPB or VVB.

Early portal vein thrombosis after pediatric split liver transplantation with left lateral segment graft.

Early portal vein thrombosis (PVT) represents a serious complication after liver transplantation (OLTx). From October 1997 through July 2004, 260 OLTx were performed in 231 children, including 189 of left lateral segments (LLS). We retrospectively analyzed the incidence and the outcome of early PVT in this group. A daily doppler US scan was performed during the first week after transplantation. Early PVT occurred in 14 patients (8%), 10 males and four females of median age 0.77 years. The main indication for primary transplantation was biliary atresia (10), followed by Byler's disease (2), acute liver failure on cryptogenetic cirrhosis (1), and Alagille syndrome (1). Four children underwent retransplantation; three cases of thrombectomy and revision of the anastomosis, two children were treated with beta blockers, one of whom had a later failed attempt at percutaneous revascularization and eventually a meso-caval shunt. Five patients were followed with observation and no treatment. Among the four patients who died, three were in the retransplantation group and one in the thrombectomy and revision of the anastomosis group; the overall mortality was 28%. With a median follow up of 399 days, 10 patients are alive with an actuarial survival at 1 and 5 years of 72%, and graft survival rates at 1 and 5 years of 64%. PVT represents a serious complication after pediatric OLTx with LLS grafts. Prompt detection and aggressive surgical treatment in selected cases are required to reduce the mortality and graft loss.

Liver transplantation in children weighting less than 6 kg: the Bergamo experience.

Liver transplantation (OLT) remains a major medical and surgical challenge in small patients. From October 1997 through July 2004, 17 babies less than 6 kg underwent 18 OLTs. Median age and weight were 3 months (range = 1 to 9) and 4.7 kg (range = 2.2 to 5.8). Two whole, one reduced, and 15 split-liver grafts (left lateral segments) were obtained from donors of median age and weight of 11.6 years (range = 0.5 to 62) and 50 kg (range = 7 to 63). Donor-to-recipient median weight ratio (D/R) was 9.1 kg (range = 1.3 to 17.6) and median graft-to-recipient weight ratio (GRWR) was 5% (range = 3.1 to 10). The incidence of biliary complications was 23%. The only vascular complication was a portal vein thrombosis (6%). Fourteen patients (79%) are alive with good graft function at a median follow-up of 39 months (range = 0.5 to 74). Three patients (all status 1) died on postoperative day 285 (brain death), 17 (multiorgan failure), and 229 (cardiovascular failure during retransplantation). Actuarial patient survivals at 6 months and 6 years are 94% and 78% while graft survivals are 89% and 74%, respectively. Currently all the patients listed as UNOS status 2 and 3 (73%) at the time of transplant are alive. During the same period one premature neonate (1.8 kg) who presented with fulminant hepatic failure died on the waiting list after 12 days. Our data confirm that the extensive use of a split-liver technique from small adult or pediatric cadaveric donors can offer the benefits of liver transplantation to small pediatric candidates with excellent results.

Transplantation for acute liver failure in children.

We reviewed the clinical data of 30 children-hospitalized for acute liver failure in the last 6 years. Ten patients were not listed for liver transplantation OLTX. Their clinical conditions gradually improved and they are all alive without deficit. Among 20 patients listed, 15 underwent urgent OLTX. Two children died on the waiting list and three were suspended from waiting list after few days because of improvement. Survival according to age class was analyzed dividing the patients into two groups: A, age 1 year or less versus B, age between 1 and 16 years. The patient survival was 86% at 6 months and 61% both at 1 and 2 years. Survival at 6 months and 1 and 2 years was 88%, 67%, and 45% for the patients in group A and 83%, 83%, and 83% for the patients in group B (P = NS). Observing graft-to-recipient weight ratio and donor-to-recipient weight ratio most patients received an optimal sized graft. The split-liver technique is considered the preferred method of liver transplantation even in the pediatric patients with acute liver failure; especially in the setting of a cooperative system in which all livers that are suitable for split-liver transplantation are shared between centers. In order to have the best chance for survival, children with acute liver failure should be referred as soon as possible to an highly specialized pediatric liver transplantation center that can offer all the treatment modalities that are currently available.

Orthotopic liver transplantation for Byler's disease.

In this study we analyzed the features of 12 patients who underwent liver transplantation for progressive familial intrahepatic cholestasis (Byler's disease [BD]) in view of the technical features of the OLTx, incidence and type of complications, need for retransplantation, as well as patient and graft survivals. BD was the indication in 12 patients of median age 1.32 years and median weight 10 kg. Median follow-up was 670 days. Major surgical complications requiring reintervention occurred in three patients. No thrombosis of the hepatic artery was observed. Infections with positive blood cultures were diagnosed in four patients. One patient had a biliary anastomotic stenosis successfully treated by percutaneous techniques. Four patients had episodes of acute rejection treated with steroids. Two patients were retransplanted, both of whom died in the early postoperative period due to hepatic vein thrombosis and venoenteric fistula. The actuarial patient and graft survival was 83% at 1 year and 83% at 5 years. Split-liver grafts represent an excellent organ supply for these patients, achieving good results with no mortality on the waiting list.

Orthotopic liver transplantation for biliary atresia.

Biliary atresia (BA) represents the most frequent indication for liver transplantation (OLTX) in the pediatric population. The aim of this paper was to present a series collected over the last 7 years from October 1997 through July 2004, including 260 pediatric OLTX in 231 patients. BA was the indication in 137 patients. There were 69 boys and 68 girls of mean weight 10.68 kg and median age 0.9 years. As a primary transplant, 99 patients received a LLS graft; 27 a whole graft; four a I+IV-VIII segment, and two a I-IV segment. Mean follow up was 1047 days (range, 1-2496 day). Infections were diagnosed in 45 patients, vascular complications in 27 patients. Surgical complications that required reintervention occurred in 25 patients. In 41 cases biliary complications occurred, 11 requiring reintervention. 16 patients were retransplanted. In two cases another re-OLTx was performed. Currently 126 patients are alive, showing an actuarial 1 year survival of 92% and 5 year 91%, with actuarial graft survivals of 85% at 1 year and 82% at 3 and 5 years. Our results confirm the effectiveness of OLTx for the treatment of children with BA and a failed Kasai procedure. Split liver grafts represent an excellent organ supply for these patients, achieving optimal results with no mortality on the waiting list.

Use of extended right grafts from in situ split livers in adult liver transplantation: a comparison with whole-liver transplants.

INTRODUCTION: We report our experience of in situ split-liver transplantation (SLT) for adult patients and compare the results with those achieved with whole-liver transplantation (WLT). METHOD: From November 1997 to December 2003, 109 liver transplantation were performed in 104 adult patients including 90 WLT (83%) and 19 SLT (17%) grafts. Fifteen extended right grafts (ERG, segments I + IV to VIII) were obtained with in situ split-liver procedures, generating also left lateral segment grafts, which were transplanted at our institution or elsewhere. Four left lobe (LL, segments I to IV) and right lobe (segments V to VIII) grafts were obtained by a modified in situ procedure for adult recipients. UNOS status, percentage of primary or secondary transplantation, and underlying liver disease were similar among patients receiving whole versus split grafts. Donors were older in whole than ERG cohorts (53 vs 26 years, P < .001). Procurement parameters and intraoperative profiles of transplant procedure were comparable among the groups. RESULTS: Median follow-up was 18 months (range: 1 to 73). Four patients with whole (4%) and no patient with ERG underwent retransplantation (P = NS). One- and 3-year patient survivals were 86% and 79% with WLT versus 93% and 93% with ERG (P = NS). One- and 3-year graft survivals were 84% and 75% with WLT versus 93%, and 93% with ERG (P = NS). Incidence of vascular complications was 8% with WLT, 13% with ERG (P = NS). The incidence of biliary complications was 13% in WLT, 27% in ERG (P = NS). CONCLUSIONS: The use of ERG from in situ split livers for adult transplantation allowed us to obtain results comparable or even better than those obtained with WLT. Split-liver transplantation is an effective, safe mechanism to expand the cadaveric donor pool.

Orthotopic liver transplantation for alagille syndrome.

Alagille syndrome (AS) is a dominantly inherited, multisystem disorder involving the liver, heart, eyes, face, and skeleton. From October 1997 through July 2004, 260 pediatric orthotopic liver transplantations (OLTx) were performed in 231 patients. This report describes 21 patients of median age 1.95 years (range, 0.7-16.7) who had alagille syndrome. We present the technical features of the OLTx, incidence and type of complications, medical conditions related to the syndrome, need for retransplantation, as well as patient and graft survival rates. A split liver technique was used in 16 patients (76%) who received a left lateral segment (LLS) graft whereas 7 patients (33%) received a whole liver. Only cadaveric donors were used. The major surgical complications requiring reintervention in 11 patients (52%) included biliary problems (19%) and vascular complications (17%). One case of hepatic artery thrombosis required retransplantation. Three recipients (14%) died. All other patients are alive with an actuarial survival rate of 90% at 1 year and 80% at 5 years. The actuarial graft survival rate is 85% at 1 year and 75% at 5 years. Patients with AS, despite the associated cardiovascular anomalies, can be treated successfully by a combined approach between cardiologist, radiologist, cardiothoracic, and liver transplant surgeons. With careful planning and operative management, the results are comparable with those obtained with other more common cholestatic diseases.

Transverse spatial coherence of a transient nickellike silver soft-x-ray laser pumped by a single picosecond laser pulse.

The degree of spatial coherence in the direction perpendicular to the target surface is reported for a transient nickellike silver x-ray laser at 13.9 nm. An x-ray laser plasma column was produced by irradiating a slab silver target with a single shaped picosecond laser pulse with energy less than 3 J. Young's double-slit method was applied to measure the fringe visibility as a function of the slit separation for different target lengths. The diameter of the equivalent incoherent source and the coherence radius of the output radiation were determined as well.