Prolonged Ischemia Time Research Articles

Pre-injury level of anxiety is associated with the rate of digit replant failure: A prospective cohort study

Previous studies have demonstrated that age, smoking, Tamai's level of amputation, causes of injury and ischemia time were associated with the success rate of digit replantation. The primary objective of this study is to investigate whether mental status including anxiety and depression is associated with the rate of digit replant failure. This study included 134 digits from 102 patients who received digital replantation after complete amputation from 1 September 2013 to 1 September 2015. The Zung self-rating anxiety scale (SAS) and the Zung self-rating depression scale (SDS) were used to assess the pre-injury level of anxiety and depression for each patient. All participants were followed up for at least 1 month. Failure was defined as necrosis of replanted finger which required revision amputation or flap cover of the skeleton. Multivariate logistic regression analysis showed that increased level of pre-injury anxiety was an independent risk factor correlated with success rate (odds ratios [OR] = 7.69, 95% confidence interval [CI]: 1.93-30.30) in this series. The relative risk of anxiety group was 4.48 (95% CI: 1.38-14.49) compared to normal group. Digits with double arterial anastomosis in anxiety patients showed a higher survival rate while the number of veins repaired showed no significant effect on survival rate. Increased level of pre-injury anxiety was an independent risk factors for digit replantation failure. Double arterial anastomosis increased the success rate of replanted digits in anxiety patients.

Does duration of donor brain injury impact heart transplantation outcomes?

We aimed to study the implications of pre-transplantation time intervals on HT outcomes. Brain injury time (BIT) was defined as the period from the donor brain injury to brain death declaration. Brain death interval (BDI) was defined as the period from brain death to application of an aortic cross-clamp during donor heart procurement. Allograft ischemia was defined as the time from donor aortic cross-clamp to aortic unclamping. End points included mortality and rejections. Between 1997 and 2017, we assessed 173 patients. Kaplan-Meier analyses showed that prolonged donor BIT, BDI, allograft ischemia, and total injury time had no significant effect on mortality and rejections. Patients were subdivided into short BIT (<97hours, n=87) and long BIT (≥97hours, n=86) groups. No differences in rejection scores nor in time to first rejection were noted. Kaplan-Meier analysis showed a similar long-term survival in the two groups. Sub-analysis of both groups according to their median BDI (12hours) revealed no differences in mortality or time to rejection. Pre-transplantation time intervals do not affect mortality or rejection. Our findings have important clinical implications regarding HT allocation and organ availability.

The fate of delayed revascularization for neglected vascular injury of incompletely amputated digits and hands.

We report the fate of neglected vascular injury in cases of incomplete amputation of the digits and hand after delayed revascularization. Twelve patients underwent primary bone fixation, tendon or skin repair for hand injuries without vessel repair despite ischaemic findings. There was discoloration or necrosis of the fingertips during follow-up examination and the patients were referred to us for treatment. The mean warm ischaemic time was 53 hours (range 17-120). Delayed revascularization was performed with end-to-end anastomosis of the digital arteries in eight and vein graft in four cases. Digital nerves were repaired in four cases and flexor tendons in two cases. Of the 12 cases, eight cases showed complete survival. However, in four patients, complete necrosis of the fingers occurred, with one finger surviving partially. Revision amputation was performed in the four cases where necrosis occurred. We conclude that neglected vascular injury associated with incomplete amputation of digits and hands can be overcome in some patients by delayed revascularization even after prolonged warm ischaemic time. Level of evidence: IV.

Outcome Prediction after Surgical Management of Prosthetic Mitral Valve Dysfunction; a single center experience

Background: Prosthetic Mitral valve dysfunction is a serious complication associated with a high mortality rate particularly in obstructive cases. The number of cases undergoing redo mitral valve surgery is increasing. This study aims to identify the risk factors of mortality and morbidity in patients who underwent redo mitral valve surgery for prosthetic mitral valve dysfunction.&#x0D; &#x0D; Methods: This study was conducted on 80 patients who underwent re-operation for management of prosthetic mitral valve dysfunction from December 2014 to February 2018. Patients’ age ranged between 21 and 58 years with a mean of 36.8±9.60 years, and 53 patients (66.3%) were males. The causes of mitral valve malfunction were thrombus in 67 patients (83.7%) and pannus in 13 patients (16.3%).&#x0D; Results: 53 patients (66.25%) had urgent surgical intervention. Thrombectomy or pannus resection was done in 75 patients (93.75%) and valve replacement in 5 patients (6.25%). Re-exploration was required in 11 patients (13.75%) and was significantly associated with diabetes (p= 0.004), preoperative liver dysfunction (p= 0.04), elevated INR (p= 0.006), trial of thrombolysis (p&lt;0.001) and prolonged ischemic time (p= 0.01). Postoperative renal failure occurred in 11 patients (13.75%) and was associated with diabetes (p&lt; 0.001), preoperative renal dysfunction (p&lt; 0.001), prolonged cardiopulmonary bypass and ischemic times (p&lt; 0.001). 17 patients (21%) required prolonged mechanical ventilation and it was significantly associated with chronic obstructive lung disease (p&lt; 0.001), pulmonary edema (p &lt;0.001), low systolic blood pressure (p &lt;0.001), low ejection fraction (p&lt;0.001) and thrombectomy (p&lt;0.001). Operative mortality occurred in 13 patients (16%) and was significantly associated with preoperative stroke, renal dysfunction, low blood pressure and acute pulmonary edema (p &lt;0.001).&#x0D; Conclusion: Reoperation for prosthetic mitral valve dysfunction is associated with high morbidity and mortality. Outcomes can be predicted based on preoperative clinical status and operative times. Thrombectomy and pannus resection with the repair of the paravalvular leak is a simple and easy technique for management of those patients with a reduction of cardiopulmonary bypass and cross-clamp times.

Reduction of Warm Ischemia Using a Thermal Barrier Bag in Kidney Transplantation: Study in a Pig Model

BackgroundWith recent advances in surgical technologies, minimally invasive endoscopic and robot-assisted surgical procedures have been introduced. However, prolonged warm ischemic time of the kidneys remains a concern after the organ is removed from a donor and during transplantation into a recipient. We developed a Thermal Barrier Bag (TBB) to prevent warm ischemia during transplantation. To confirm the effectiveness of the TBB, adenosine triphosphate (ATP) activity in the kidney was measured during an ex vivo warming test. An ischemia model porcine kidney was also used as the donor kidney and placed into the TBB; thereafter, the change in temperature at the time of transplantation was examined. Main FindingsThe purse-like design of the TBB efficiently suppressed heat conduction. A simulation was conducted that allowed the calculation of organ heat transfer condition. In the ex vivo experiment, temperature increases were suppressed in the group whose kidneys were placed in the TBB (30 minutes after transplantation: with TBB = 30°C, without TBB = 35°C). ATP measurements showed that the residual rate was substantially higher in the TBB group (P = .056). Moreover, a temperature suppression effect was demonstrated during the renal transplantation experiment (30 minutes after transplantation: with TBB = 27°C, without TBB = 31°C). ConclusionThe ex vivo warming experiment demonstrated that use of TBB slows down the rate of ATP decay in fresh kidneys. In addition, when an ischemic model porcine kidney was placed into the TBB and the temperature change at the time of transplantation was measured, an in vivo temperature-suppressing effect was observed.

Post-transplant outcome in patients bridged to transplant with temporary mechanical circulatory support devices.

The new heart allocation system in the United States prioritizes patients supported by temporary mechanical circulatory support (TMCS) devices over those with uncomplicated durable continuous-flow left ventricular assist devices (CF-LVADs), which may increase the number of patients bridged to transplant with TMCS. Limited data are available in guiding post-transplant outcomes with various TMCS devices. We sought to describe post-transplant outcome and identify clinical variables associated with post-transplant outcome in patients bridged to transplant with TMCS. Using data from the International Society for Heart and Lung Transplantation Thoracic Transplant Registry, we included subjects who underwent transplantation between 2005 and 2016 with known use of mechanical circulatory support. Pre-transplant recipient, donor, and transplant-specific variables were abstracted. The primary outcome was patient survival at 1-year post-transplant. Outcomes of patients bridged to transplant with TMCS were compared with those of patients bridged with CF-LVADs. Cox regression analyses were performed to identify clinical variables associated with the outcomes. There were 6,528 patients bridged to transplant with the following types of mechanical circulatory support: durable CF-LVADs (n = 6,206), extracorporeal membrane oxygenation (ECMO, n = 134), percutaneous temporary CF-LVADs (n = 75), surgically implanted temporary CF-LVADs (n = 38) or surgically implanted temporary BiVAD (n = 75). Bridging with ECMO (hazard ratio 3.79, 95% confidence interval [CI] 2.69-5.34, p < 0.001) or percutaneous temporary CF-LVADs (hazard ratio 1.83, 95% CI 1.09-3.08, p = 0.02) was independently associated with higher risk of mortality. Additional risk factors included older donor age, female/male donor-recipient match, older recipient age, higher recipient body mass index, higher recipient creatinine, and prolonged ischemic time. This analysis of a large international cohort of patients bridged to transplant with mechanical circulatory support identified ECMO and percutaneous temporary CF-LVADs as predictors of mortality after transplant, along with additional donor and recipient clinical characteristics. These findings may provide guidance to clinicians in decisions on mechanical circulatory support device selection, transplant eligibility, and timing of transplant.

Uso de homoinjertos en la endocarditis sobre válvula aórtica nativa

Introduction and objectivesThe type of prosthesis used in infective endocarditis surgery of the native aortic valve depends largely on the age of the patient and the preferences of the surgeon. There is little information on the use of allografts in these patients. MethodsA total of 20 cases of infective endocarditis of the native aortic valve were treated in our centre from 1997 to 2017, using allograft implants. ResultsThe mean age of patients was 60 ± 12 years, the negative blood culture rate was 20%, and the main causal agent was enterococci (30%). Patients underwent urgent surgery in 70% of the cases, with an ischaemia time of 112 ± 32min, and 9 patients (45%) died during the active phase. Re-intervention, major bleeding or re-infection were infrequent, and 3 patients died during follow-up. ConclusionsPatients with infective endocarditis on the native valve in whom an allograft homograft is implanted, frequently have to undergo urgent surgery, have prolonged ischaemia times and their short and long-term prognosis is unfavourable.

Abstract 17: Increasing Ischemia Time Diminishes Chimerism After Vascularized Bone Marrow Allotransplantation

PURPOSE: Vascularized composite allotransplantation (VCA) can include vascularized bone marrow (VBM) to potentially generate chimerism and subsequent tolerance in the recipient. While increasing ischemia time is known to be detrimental to free flaps and solid organ transplants, it is unknown whether increasing VCA ischemia time may diminish VBM’s capacity to achieve chimerism and tolerance. This study determines whether increasing cold ischemia time results in decreased peripheral chimerism levels, increasing loss of the donor bone marrow compartment, and increased skin paddle rejection in a murine VCA model. METHODS: Twenty-three adult Lewis rats received osteomyocutaneous hind limb allografts from 3 groups of Brown-Norway rats. The groups underwent 0, 6, and 12 hours of cold ischemia at 4°C (n=8, 6, and 9 respectively). Immunosuppressive conditioning consisted of anti-lymphocyte serum 1cc 3 days pre-operatively and on post-op day (POD) 1, tacrolimus 2mg/kg/day for PODs 1–7, and then concluded with rapamycin 3mg/kg/day for PODs 8–28. Peripheral chimerism levels were drawn after POD 30. Skin paddle was observed for 30 days after immunosuppression cessation for rejection or tolerance. Allograft was collected at POD 60 for flow cytometry and histologic analysis. RESULTS: Peripheral chimerism levels in both myeloid and lymphoid lines were decreased in the 12 & 6 hours groups versus 0 hours (p<0.01). At POD 60, the amount of donor cells in the allograft bone marrow was significantly decreased at 12 & 6 hours versus the 0 hours group (p<0.05). At 12 hours, hematoxylin & eosin histology demonstrated significantly increased reactive lymphocytes, increased stroma, significantly decreased hematopoetic cells, and significant myelofibrosis. At 6 hours, moderate stromal increases, moderately decreased hematopoetic cells, and moderate myelofibrosis was observed. Trichrome staining revealed viable bone at all time points though with there were increasing amounts of collagen deposition with increasing ischemia and osteoslerosis was noted at 12 hours. Microvasculature was preserved at all time points. By POD 60, 0% of skin paddles survived in the 12 hours group, 17% at 6 hours, and 73% at 0 hours. CONCLUSION: With increasing ischemia time prior to VCA re-vascularization, there is decreased peripheral chimerism levels, increased loss of donor hematopoetic cells in the donor bone marrow, and increased skin paddle rejection. These findings indicate that ischemia time may significantly limit the capacity for VBM to facilitate chimerism and subsequent VCA tolerance and thus strategies using VBM to induce tolerance may need to consider the additional obstacle of time. Prolonged ischemia time may be a contributing factor to the absence of stable chimerism and tolerance in human VBM-bearing VCA recipients.

Liver graft preservation methods during cold ischemia phase and normothermic machine perfusion.

The growing demand for donor organs requires measures to expand donor pool. Those include extended criteria donors, such as elderly people, steatotic livers, donation after cardiac death, etc. Static cold storage to reduce metabolic requirements developed by Collins in late 1960s is the mainstay and the golden standard for donated organ protection. Hypothermic machine perfusion provides dynamic organ preservation at 4°C with protracted infusion of metabolic substrates to the graft during the ex vivo period. It has been used instead of static cold storage or after it as short perfusion in transplant center. Normothermic machine perfusion (NMP) delivers oxygen, and nutrition at physiological temperature mimicking regular environment in order to support cellular function. This would minimize effects of ischemia/reperfusion injury. Potentially, NMP may help to estimate graft functionality before implantation into a recipient. Clinical studies demonstrated at least its non-inferiority or better outcomes vs static cold storage. Regular grafts donated after brain death could be safely preserved with convenient static cold storage. Except for prolonged ischemia time where hypothermic machine perfusion started in transplant center could be estimated to provide possible positive reconditioning effect. Use of hypothermic machine perfusion in regular donation instead of static cold storage or in extended criteria donors requires further investigation. Multicenter randomized clinical trial supposed to be completed in December 2021. Extended criteria donors need additional measures for graft storage and assessment until its implantation. NMP is actively evaluating promising method for this purpose. Future studies are necessary for precise estimation and confirmation to issue clinical practice recommendations.

Association between Allograft Ischemic Time and Adverse Outcomes Following Lung Transplantation

Purpose Efforts to increase the number of viable donors, such as ex vivo lung perfusion and donation after circulatory death, are likely to significantly alter allograft ischemic time distributions. As such, understanding the impact allograft ischemia has on short and long-term outcomes will be key in determining best practices going forward. Methods We conducted an ISHLT database study of adult bilateral lung transplant recipients between January 1, 2006 and June 30, 2016. We evaluated for an association between first and second lung ischemic time and short- and long-term outcomes post-transplant. We also performed regression modeling to evaluate factors associated with prolonged ischemic time. Results 13,183 recipients were included in the final analysis. Prolonged first but not second lung ischemic time was associated with decreased unadjusted 30-day survival (log-rank p=0.048) and higher rates of treated acute rejection in the first post-transplant year (p Conclusion First allograft ischemic time appears more strongly associated with increased 30-day and 1-year mortality as well as prolonged index hospitalization and increased acute rejection in the first year. This suggests that, in bilateral lung recipients, first lung ischemic time is more clinically relevant to allograft and patient outcomes.

Donors after Circulatory Death at the Medical College of Wisconsin and Potential for Increased Volume in Cardiac Transplantation

Purpose The purpose of this study is to investigate the potential donor pool expansion that could occur through implementing a strategy for donors after circulatory death (DCD) heart transplantation. Methods A retrospective review of the Wisconsin Donor Network Organ Procurement (WIDN OPO) database between July 1, 2015 and June 30, 2017 was completed. The DCD population (n = 54) was stratified between high, moderate, and low risk via point analysis, based on previously published risk assessment tools. High risk features included advanced age, prolonged warm ischemic time or cardiopulmonary resuscitation, evidence of myocardial dysfunction, or active infection. Potential donors with prior cardiac history, mechanical circulatory support, age greater than 60, or active malignancy were excluded. For DCD donors with incomplete cardiac data, we assumed the percentage of normal cardiac function and biomarkers to resemble donors after brain death. Results Over two years the WIDN OPO had a total of 499 solid organ transplants from 172 donors, with 54 DCD referrals, 46 DCD going to transplant, and 15 local to Froedtert Hospital. Of the 54 DCD referrals, 28% (n = 15) had a complete cardiac evaluation with two donors falling into moderate risk category. Seventy-two percent (n = 39) of DCD donors did not have complete cardiac data prior to donation, and risk stratification of remaining variables revealed 35% low risk (n = 19), 31% moderate risk (n = 11), and 18% high risk (n = 10). Given 87% of brain death donors have normal echocadiograms and cardiac biomarkers, and applying that to the DCD donor population with incomplete cardiac data, 28% (n = 14) and 16% (n = 9) fell into the low and moderate risk categories respectively. Conclusion Instituting a DCD program for the WIDN OPO may yield a 21% increase, or an additional 19 heart transplants categorized as low risk based on traditional high risk features.

Impaired Outcome after Heart Transplantation: Impact of Donor Age and Ischemic Time

Purpose In times of organ shortage and an increasing number of patients waiting for heart transplantation (htx), the decision for refusal of organs has to be made carefully. It is still discussed controversially to which extent one can accept hearts from older donors or with expected prolonged ischemic times. Methods Between 2010 and 07/2018, 108 patients underwent heart transplantation in our department. These recipients were retrospectively divided into 4 groups with regard to donor age and total ischemic time (TIT). Group 1 patients received hearts from donors Results Group 1 consisted of 42 patients, group 2, 3 and 4 of 26, 35 and 5 patients. Thirty-day mortality was 2.4 % in group 1, 7.7 % in group 2 and significantly higher in groups 3 and 4 with 22.9 % and 40 % (p Conclusion With our results we could show, that a longer ischemic time is acceptable in younger donors. However, in donors elder than 50 years organ acceptance should be made with great caution if the presumed ischemic time exceeds four hours. The decision mostly depends also on recipient´s status which may influence the willing to undergo an increased risk.

Therapeutic Strategies of Kidney Transplant Ischemia Reperfusion Injury: Insight From Mouse Models

Ischemia/reperfusion injury (IRI) is inherent to all transplanted organs and is adversely associated with early renal graft function and graft longevity. Despite the progress in immunosuppressive regimens and perioperative care, no FDA-approved treatment for kidney transplant IRI is available to date. In recent years, by utilizing the modified and clinically-relevant mouse models of kidney transplantation (KTx) in which extended IRI is induced by the prolonged warm or cold ischemic time, studies have identified several potential therapeutic approaches for KTx IRI, including the hormone supplement, promoting tubular repair and regeneration, and targeting complement system, inflammation, and necroptosis. This review describes some of the lessons learned from mouse models of KTx with regard to factors that influence the severity of transplant IRI and the potential therapeutic targets.

Can hypothermic oxygenated perfusion (HOPE) rescue futile DCD liver grafts?

BackgroundThe new UK-DCD-Risk-Score has been recently developed to predict graft loss in DCD liver transplantation. Donor-recipient combinations with a cumulative risk of >10 points were classified as futile and achieved an impaired one-year graft survival of <40%. The aim of this study was to show, if hypothermic oxygenated perfusion (HOPE) can rescue such extended DCD livers and improve outcomes. Methods“Futile”-classified donor-recipient combinations were selected from our HOPE-treated human DCD liver cohort (01/2012-5/2017), with a minimum follow-up of one year. Main risk factors, which contribute to the classification “futile” include: elderly donors>60years, prolonged functional donor warm ischemia time (fDWIT > 30min), long cold ischemia time>6hrs, donor BMI>25 kg/m2, advanced recipient age (>60years), MELD-score>25points and retransplantation status. Endpoints included all outcome measures during and after DCD LT. ResultsTwenty-one donor-recipient combinations were classified futile (median UK-DCD-Risk-Score:11 points). The median donor age and fDWIT were 62 years and 36 min, respectively. After cold storage, livers underwent routine HOPE-treatment for 120 min. All grafts showed immediate function. One-year and 5-year tumor death censored graft survival was 86%. ConclusionHOPE-treatment achieved excellent outcomes, despite high-risk donor and recipient combinations. Such easy, endischemic perfusion approach may open the door for an increased utilization of futile DCD livers in other countries.

High-grade atrioventricular block requiring pacemaker implantation after cardiac transplantation: An unusual complication

Self-limited bradyarrhythmias are commonly seen in postorthotopic heart transplantation patients. The most common cause of such bradyarrhythmias is sinus node dysfunction. Atrioventricular (AV) nodal blocks requiring pacemaker implantation remain distinctly uncommon. After ruling out reversible causes including dyselectrolytemia and drug toxicity, prolonged ischemia time of donor heart and transplant rejection should be considered as possible causes. The present case describes an uncommon occurrence of persistent high-grade AV block in postheart transplantation period ultimately requiring permanent pacemaker implantation.

Predictors and prognosis of no-reflow during primary percutaneous coronary intervention

The no-reflow phenomenon occurs in a considerable number of patients with ST elevation myocardial infarction (STEMI) undergoing primary reperfusion therapy. Our study aimed to identify clinical, angiographic, and procedural variables that predict this phenomenon in patients with STEMI undergoing primary percutaneous coronary intervention (PPCI), as well as determine the impact of no-reflow on in-hospital mortality. Prospective observational data from 410 patients with STEMI undergoing PPCI were obtained. In this study, diabetes mellitus, late presentation, higher Killip class at admission, anterior wall infarction, proximal site of occlusion, presence of high-grade thrombus, and left ventricular systolic dysfunction at admission were significantly associated with suboptimal coronary flow. Diabetes mellitus, a high thrombus burden, prolonged total ischemic time, and low left ventricular ejection fraction on admission were independent predictors of no-reflow. No-reflow during PPCI was associated with in-hospital mortality more than twice that for normal flow.

Secondary Fill Minimizes Gutter Size in Chimney EVAS Configurations In Vitro

Purpose: To investigate in an in vitro model if secondary endobag filling can reduce gutter size during chimney endovascular aneurysm sealing (chEVAS). Materials and Methods: Nellix EVAS systems were deployed in 2 silicone juxtarenal aneurysm models with suprarenal aortic diameters of 19 and 24 mm. Four configurations were tested: EVAS with 6-mm balloon-expandable (BE) or self-expanding (SE) chimney grafts (CGs) in the renal branches of both models. Balloons were inflated simultaneously in the CGs and main endografts during primary and secondary endobag filling and polymer curing. Computed tomography (CT) was performed immediately after the primary and secondary fills. Cross-sectional lumen areas were measured on the CT images to calculate gutter volumes and percent change. CG compression was calculated as the reduction in lumen surface area measured perpendicular to the central lumen line. The largest gutter volume and highest compression were presented per CG configuration per model. Results: Secondary endobag filling reduced the largest gutter volumes from 99.4 to 73.1 mm3 (13.2% change) and 84.2 to 72.0 mm3 (27.6% change) in the BECG configurations and from 67.2 to 44.0 mm3 (34.5% change) and 92.7 to 82.3 mm3 (11.2% change) in the SECG configurations in the 19- and 24-mm models, respectively. Secondary endobag filling increased CG compression in 6 of 8 configurations. BECG compression changed by −0.2% and 5.4% and by −1.0% and 0.4% in the 19- and 24-mm models, respectively. SECG compression changed by 10.2% and 16.0% and by 7.2% and 7.3% in the 19- and 24-mm models, respectively. Conclusion: Secondary endobag filling reduced paragraft gutters; however, this technique did not obliterate them. Increased CG compression and prolonged renal ischemia time should be considered if secondary endobag filling is used.

Static Cold Storage vs Ex Vivo Machine Perfusion: Results From a Comparative Study on Renal Transplant Outcome in a Controlled Donation After Circulatory Death Program

IntroductionWe aimed to evaluate if ex vivo machine perfusion could minimize the negative impact of cold ischemia on those renal grafts obtained from controlled donation after circulatory death (cDCD). Material and methodsProspective observational paired study of kidney transplants from cDCD performed in our center. The kidney from each pair preserved on ice was transplanted first within the first few hours following procurement, while the contralateral kidney was machine-perfused with a LifePort device (Organ Recovery Systems, Brussels, Belgium) and transplanted the following day. ResultsA total of 12 cDCDs were included. No differences were observed in delayed graft dysfunction or graft survival between the 2 groups. ConclusionThe use of ex vivo perfusion devices is simple and they do not require any large infrastructural or high economic investments, considering the fact that it allows a better selection of recipients and viable organs no longer need to be discarded because of prolonged warm ischemia times.

Coronary No-Reflow Phenomenon in Clinical Practice

Timely delivered coronary revascularization with no residual anatomical stenosis does not always lead to prompt restoration of anterograde coronary flow and complete myocardial reperfusion. This condition is known as coronary no-reflow and is associated with major clinical adverse events and poor prognosis. The pathophysiology of no-reflow phenomenon is still poorly understood. Proposed mechanisms include distal microembolization of thrombus and plaque debris, ischemic injury, endothelial dysfunction and individual susceptibility to microvascular dysfunction/obstruction. Older age, diabetes, hypercholesterolemia, prolonged ischemic time, hemodynamic instability, high thrombus burden, complex angiographic lesions and multivessel disease are frequently reported to be associated with the no-reflow phenomenon. There is no general consensus on the correct prevention and management of no-reflow. Non-pharmacological measures such as distal embolic protection devices and manual thrombus aspiration did not result in improved flow or reduction of infarct size. Current preventive measures include reduction of time from symptoms onset to reperfusion therapy, and intracoronary administration of vasodilators such as adenosine, verapamil or nitroprusside.

Risk factors for infection after pediatric lung transplantation.

Although infection is the leading cause of death in the first year following pediatric lung transplantation, there are limited data on risk factors for early infection. Sepsis remains under-recognized and under-reported in the early post-operative period for lung transplant recipients (LTR). We evaluated the incidence of infection and sepsis, and identified risk factors for infection in the early post-operative period in pediatric LTRs. A retrospective review of medical records of LTRs at a large quaternary-care hospital from January 2009 to March 2016 was conducted. Microbiology results on days 0-7 after transplant were obtained. Sepsis was defined using the 2005 International Pediatric Consensus Conferencecriteria. Risk factors included history of recipient and donor infection, history of multi-drug resistant (MDR) infection, nutritional status, and surgical times. Among the 98 LTRs, there were 22 (22%) with post-operative infection. Prolonged donor ischemic time ≥7hours, cardiopulmonary bypass(CPB) time ≥340minutes, history of MDR infection and diagnosis of cystic fibrosis were significantly associated with infection. With multivariable regression analysis, only prolonged donor ischemic time remained significant (OR 4.4, 95% CI: 1.34-14.48). Further research is needed to determine whether processes to reduce donor ischemic time could result in decreased post-transplant morbidity.