Slipping Rib Syndrome in Children: Natural History and Outcomes Following Costal Cartilage Excision.

INTRODUCTION: Slipping rib syndrome (SRS) or subluxation of the medial aspect of the lower rib costal cartilages is an underdiagnosed cause of debilitating pain in otherwise healthy children. Costal cartilage excision may provide definitive symptom relief. However, limited data exist on the natural history, difficulty in diagnosis, and patient-reported outcomes for SRS in children. METHODS: We performed a single-institution descriptive study using chart review and a patient-focused survey for patients who underwent surgery for SRS from 2012 to 2020. Data regarding demographics, symptoms, diagnostic workup, and patient-reported outcomes were collected. RESULTS: Surgical resection was performed in 13 children. The median age at symptom onset was 12.5 y [IQR 9.7, 13.9], with a preponderance of girls (10, 77%). Eight patients participated in competitive athletics at the time of symptom onset. Prior to diagnosis, patients were seen by a median 3 [IQR 2, 5] providers with a median of 4 [IQR 3, 6] non-diagnostic imaging exams performed. The children included in the study underwent surgery for left (8), bilateral (4), and right (1) SRS. Two were lost to follow-up. At median post-op follow-up of 3.5 mo [IQR 1.2, 9.6], 73% (8/11) had returned to full activity. One reported non-limiting persistent pain symptoms. CONCLUSIONS: Lack of knowledge regarding SRS may result in delayed diagnosis, excessive testing, and limitation of physical activity. Operative treatment appears to provide durable relief and should be considered for children with SRS. The challenge remains to decrease the number of non-diagnostic exams and time to diagnosis.

A Narrative Review of Postoperative Anticoagulation Therapy for Congenital Cardiac Disease.

Congenital heart disease encompasses a range of cardiac birth defects. Some defects require early and complex surgical intervention and post-operative thromboprophylaxis primarily for valve, conduit, and shunt patency. Antiplatelet and anticoagulant management strategies vary considerably and may or may not align with recognized consensus practice guidelines. In addition, newer anticoagulant agents are being increasingly used in children, but these medications are not addressed in most consensus statements. This narrative review evaluated the literature from 2011 through 2021 on the topic of postoperative thromboprophylaxis after congenital heart disease operations. The search was focused on the descriptions and results of pediatric studies for replacement and/or repair of heart valves, shunts, conduits, and other congenital heart disease operations. Wide variability in practice exists and, as was true a decade ago, few randomized controlled trials have been conducted. Aspirin, warfarin, and perioperative heparin remain the most commonly used agents with varying dosing, duration, and monitoring strategies, making comparisons difficult. Only recently have data on direct oral anticoagulants been published in children, suggesting evolving paradigms of care. Our findings highlight the need for more research to strengthen the evidence for standardized thromboprophylaxis strategies.

Impact of Continuous Renal Replacement Therapy on Bivalirudin Dosing in Pediatric Extracorporeal Membrane Oxygenation.

There is an increasing interest in the use of bivalirudin for pediatric extracorporeal membrane oxygenation (ECMO) anticoagulation. However, dosing is not well described in those requiring continuous renal replacement therapy (CRRT). We aimed to determine whether CRRT affects bivalirudin dosing in pediatric ECMO patients. Children ≤18 years of age placed on ECMO and anticoagulated with bivalirudin for ≥24 hours from January 2019 to May 2020 were included. Bivalirudin doses were collected for 144 hours from initiation of bivalirudin or CRRT. Analysis was performed to determine whether CRRT, age, or weight affected bivalirudin dosing. Thirty-one children were included, and 11 (35%) required concomitant CRRT. There was no difference in age (median 9.1 versus 3.2 months, p = 0.15) or days on ECMO (median 11 versus 9, p = 0.7) between those who did or did not receive CRRT. The mean bivalirudin dosing was similar in patients who did or did not require CRRT (median and IQR: 0.13 mg/kg/hour [0.08-0.26] versus 0.15 mg/kg/hour [0.11-0.22], respectively, p = 0.13). Younger age ( p < 0.001) and lower weight ( p < 0.001) were associated with higher bivalirudin dosing. In our study, bivalirudin dosing did not differ if the patient required CRRT while on ECMO.

Improved Outcomes of Infant Lung Transplantation Over 3 Decades.

BACKGROUND: Lung transplantation is the definitive surgical treatment for end-stage lung disease. However, infants comprise less than 5% of pediatric cases. This study sought to provide an overview of infant lung transplantation outcomes over the past 3 decades by using linked United Network for Organ Sharing (UNOS) and Pediatric Health Information System (PHIS) data. METHODS: Infants undergoing lung transplantation from 1989 to 2020 in UNOS were reviewed. UNOS and PHIS records for patients who underwent lung transplantation from 1995 to 2020 were linked using date of birth, sex, and date of surgery ± 3 days. The study assessed underlying diagnoses, pretransplant and posttransplant extracorporeal membrane oxygenation support, retransplant-free survival to discharge, hospital experience (≥1 annual transplant for ≥4 years in a 5-year period), operative decade, bronchiolitis obliterans syndrome, long-term survival, and functional status at latest follow-up. RESULTS: A total of 112 lung transplants were performed in 109 infants over 31 years. Of these, 21 patients died before discharge, and 2 underwent repeat transplantation during the same admission. The study linked 80.6% (83 of 103) of UNOS and PHIS records. Hospital survival was lower for infants with idiopathic pulmonary hypertension and those who underwent transplant procedures at less experienced centers. All 7 infants requiring postoperative extracorporeal membrane oxygenation support died. Median freedom from bronchiolitis obliterans syndrome was 8.1 years (interquartile range, 4.6 to 11.6 years). After discharge, median survival was 10.3 years (interquartile range, 6.3 to 14.4 years), with improved 10-year survival for those patients who underwent transplantation from 2010 to 2020 (87.3%) vs 2000 to 2009 (52.4%; P = .098) and 1989 to 1999 (34.1%; P = .004). A total of 84.6% (33 of 39) of survivors had minor or no restrictions at latest follow-up. CONCLUSIONS: Carefully selected infants experience promising short- and long-term outcomes after lung transplantation.

A comparison of cardiopulmonary bypass versus extracorporeal membrane oxygenation: Does intraoperative circulatory support strategy affect outcomes in pediatric lung transplantation?

OBJECTIVE: Data on adult lung transplantation suggest perioperative benefits of intraoperative extracorporeal membrane oxygenation (ECMO) compared to cardiopulmonary bypass (CPB). Information regarding their pediatric counterparts, however, is limited. This study compares outcomes of intraoperative ECMO versus CPB in pediatric lung transplantation. METHODS: We reviewed all pediatric lung transplants at our institution from 2014 to 2019 and compared those supported intraoperatively on ECMO (n = 13) versus CPB (n = 22), plus a conditional analysis excluding re-transplantations (ECMO [n = 13] versus CPB [n = 20]). We evaluated survival, surgical times, intraoperative transfusions, postoperative support, complications, and duration of hospitalization. RESULTS: Total time on ECMO support was significantly less than that of CPB support (P = .018). Intraoperatively, the ECMO group required fewer transfusions of fresh-frozen plasma (8.9 [5.8-22.3] vs 16.6 [11.4-39.0] mL/kg, P = .049) and platelets (4.2 [0.0-6.7] vs 8.0 [3.5-14.0] mL/kg, P = .049). When excluding re-transplantations, patients on ECMO required fewer packed red blood cells intraoperatively (12.6 [2.1-30.7] vs 28.2 [14.0-54.0] mL/kg, P = .048). There were no differences in postoperative support requirements, complications, or mortality at one, six, and twelve months. CONCLUSIONS: Intraoperative ECMO support during pediatric lung transplantation appears to decrease intraoperative transfusion requirements when compared to CPB. Data from additional institutions may strengthen these observations.

Outcomes 60 years after surgical valvotomy for isolated congenital pulmonary valve stenosis.

Congenital pulmonary valve stenosis (PVS) is a common congenital heart defect. In the infancy of cardiac surgery, open surgical valvotomy or closed surgical transventricular pulmonary valvotomy (Brock procedure) were the mainstays of therapy. We report the longest-known published follow-up of two women who as young children underwent pulmonary valvotomy for PVS and subsequent uncomplicated open pulmonary valve replacement over 60 years later.

Extended sternotomy with lateral neck incision: An alternative approach for children with large apical chest masses with thoracic inlet involvement.

Pediatric tumors in the apex of the thoracic cavity are often diagnosed late due to the absence of symptoms. These tumors can be quite large at presentation with involvement of the chest wall, sympathetic chain, spine, and aortic arch. The tumors can also extend into the thoracic inlet and encircle the brachial plexus. Depending on the diagnosis, treatment may involve chemotherapy with subsequent surgery or require primary resection. Optimal exposure to resect large apical tumors with thoracic inlet extension is a surgical challenge. To date, several surgical techniques have been described to resect these tumors - including both anterior and posterior thoracic approaches. Each of these techniques can be limited by inadequate exposure of the mass. We describe an alternative approach to surgical resection of these masses that employs an extended sternotomy with a lateral neck incision. This report details two successful resections of large left apical masses with thoracic inlet involvement in children using this technique (Level of evidence 4).

Surgical considerations in infant lung transplantation: Challenges and opportunities.

Lung transplantation is a crucial component in the treatment of end-stage lung disease in infants. Traditionally, most lung transplants have been performed in older children and adults, resulting in a scarcity of data for infant patients. To address the challenges unique to this age group, novel strategies to provide the best preoperative, intraoperative, and postoperative care for these youngest patients are paramount. We review recent advances in bridge-to-transplantation therapy, including the use of a paracorporeal lung assist device, and differences in surgical technique, including bronchial artery revascularization, for incorporation into the overarching treatment strategy for infants undergoing lung transplantation.

Is anticoagulation with bivalirudin comparable to heparin for pediatric extracorporeal life support? Results from a high-volume center.

There is a paucity of data regarding the use of direct thrombin inhibitors such as bivalirudin for children on extracorporeal life support (ECLS). We sought to compare the outcomes of children on ECLS anticoagulated with bivalirudin versus heparin. Patients transitioned from heparin to bivalirudin were treated as a separate group. A single-institution, retrospective review of all consecutive children (neonate to 18 years) placed on ECLS in the cardiac or pediatric intensive care units was performed (June 2018-December 2019). Data collected included demographics, anticoagulation strategy, number of circuit interventions, blood product use on ECLS, survival to decannulation, and survival to discharge. Fifty-four children were placed on ECLS for a total of 56 runs. Demographics and venovenous versus venoarterial ECLS were similar. The bivalirudin group had longer median duration of support compared to the heparin group--11.0 days [IQR 6.2, 23.1] versus 3.3 days [2.1, 6.2], P < .001. Patients switched from heparin to bivalirudin had a similar duration of support (10.3 days [8.3, 18.3]) as those on bilvalirudin alone. However, there was no difference in red blood cell, fresh frozen plasma, or platelet transfusions. There was no difference in the number of circuit interventions, survival to decannulation or discharge. The freedom to first circuit intervention was longer with bivalirudin compared to heparin. Our data suggest that even with longer pediatric ECLS runs on bivalirudin, there were no differences in the outcomes between the heparin and bivalirudin groups, with longer freedom from first circuit intervention with bivalirudin. While this is the largest reported series comparing children on ECLS anticoagulated with heparin versus bivalirudin, larger studies are needed to determine the optimal anticoagulation strategy for this diverse and complicated group of children.

Does Ascending Aorta Size Affect Norwood Outcomes in Hypoplastic Left Heart With Aortic Atresia?

BACKGROUND: Conflicting data exist regarding the impact of ascending aorta size on outcomes after the Norwood procedure. Results from multi-institutional studies have largely relied on heterogeneous populations undergoing this surgery for different anatomic defects. Using data from the Single Ventricle Reconstruction Trial, we analyzed the impact of preoperative ascending aortic diameter on Norwood outcomes for patients with aortic atresia variants of hypoplastic left heart syndrome. METHODS: Neonates with aortic atresia and no ventricular septal defect were included and classified into four groups, based on their baseline ascending aorta echocardiographic measurements: less than or equal to 1.5 mm, 1.6 to 1.9 mm, 2.0 to 3.9 mm, and greater than or equal to 4.0 mm. Outcomes included 14-day mortality, transplant-free survival at 1 and 14 months, need for extracorporeal membrane oxygenation, length of ventilation, intensive care, and hospital stay, intensive care unit (ICU)-free days, right ventricular function, and incidence of recoarctation by 14 months. RESULTS: Overall, 292 patients were analyzed. Median length of ICU stay was significantly longer for infants with small aortas, and ICU-free days were significantly lower. There was no difference in length of mechanical ventilation or hospitalization between groups. Long-term right ventricular function and tricuspid regurgitation did not differ. Aortic arch recoarctation incidence was higher in patients with small aortic diameters. Patients with aortas less than or equal to 1.5 mm had decreased 30-day transplant-free survival. CONCLUSIONS: Infants with aortic atresia variants of hypoplastic left heart syndrome and baseline ascending aortic diameter less than or equal to 1.5 mm appear to suffer the greatest morbidity and mortality early after Norwood procedure. These infants also experienced longer stays in the ICU and higher rates of recoarctation. Ascending aortic diameter does not appear to affect long-term ventricular function.

Symptom persistence after vascular ring repair in children.

PURPOSE: Vascular rings are often diagnosed after evaluation for swallowing and breathing difficulties. Data regarding symptoms following vascular ring repair is sparse. We sought to determine whether symptoms persist using chart review and a survey. METHODS: Sixty-three patients underwent open vascular ring repair from July 2007 to May 2018. Data regarding vascular anatomy, demographics, pre- and postoperative symptoms, and chromosomal abnormalities were collected. Freedom from reoperation, 30-day mortality, and complications were assessed. Patient families were contacted for a symptom focused survey. RESULTS: The median age of surgical intervention was 14.4 months (IQR 5.8-34.7 months) for single aortic arches with an aberrant subclavian artery (SAA), and 5.3 months (IQR 1.3-10.1 months) for double aortic arches (DAA) (Table). Prior to surgery, all but two SAA were symptomatic. There was no operative mortality. Three patients required re-exploration for chylothorax, and three required late aortopexy. At last follow-up, 45% (18/40) SAA and 65% (15/23) DAA had post-operative symptoms. Fourteen patient families completed the symptom survey (10 SAA, 4 DAA). Five SAA had breathing and swallowing symptoms, and 3 SAA and 3 DAA had breathing difficulties. CONCLUSIONS: Open vascular ring repair remains a safe repair. However, further investigation of the persistent symptoms in these patients is merited. STUDY TYPE / LEVEL OF EVIDENCE: Retrospective Comparative Study, Level III.

Recanalization of an atretic intramural left main coronary artery after bypass surgery in a pediatric patient with anomalous aortic origin of the left main coronary artery arising from the right sinus of Valsalva.

We report a pediatric patient with nonatherosclerotic chronic total occlusion (CTO) of the left main coronary artery (LMCA) leading to complete LMCA atresia which was successfully recanalized via retrograde techniques through a previous internal mammary bypass graft. After the CTO was treated, the artery was found to be anomalous off the right cusp with an intramural coarse and slit-like orifice. The patient's ischemic symptoms resolved after Percutaneous Coronary Intervention (PCI), and she has continued to do well.

Surgical Versus Percutaneous Closure of PDA in Preterm Infants: Procedural Charges and Outcomes.

BACKGROUND: Studies comparing percutaneous closure of patent ductus arteriosus (PDA) with surgical ligation tend to exclude premature infants and have not assessed procedural charges. We compared our contemporary outcomes and charges of device closure to surgical ligation of PDA in preterm infants. MATERIAL AND METHODS: Preterm infants who underwent isolated PDA closure during their newborn hospitalization (January 2014 to September 2017) were grouped based on intention to treat (surgery versus device closure). Patient demographics, procedural details, and immediate postprocedural outcomes were compared. Procedural charges for device closure versus surgical ligation were compared. RESULTS: Compared with the device group (n = 33), patients undergoing surgical ligation (n = 39) were younger, smaller, and required more preoperative support (P < 0.05). The procedure time was shorter for surgical ligation (P < 0.01). Although there was no procedural mortality in either group, the complication rate was higher for device closure than for surgical ligation (15.2% versus 0%; P = 0.02). The proportion of patients returning to preprocedural respiratory support by 48 h after procedure was similar. There was a higher proportion of surgical patients who required increased inotropic support in the first 24 h after procedure (P = 0.19). The procedural charges for transcatheter device closure were twice as expensive as those for surgical ligation. CONCLUSIONS: In our early experience with percutaneous PDA closure, we found a percutaneous approach in preterm infants feasible and well tolerated. Both surgical ligation and device closure were associated with perioperative or postoperative complications. Procedural charges were higher for percutaneous closure, driven by device charge and catheterization room utilization. Further investigation is needed to establish guidelines for first-line therapy for PDA closure in preterm infants, including cost-benefit analysis.

An overview of mechanical circulatory support in single-ventricle patients.

The population of people with a single-ventricle is continually increasing due to improvements across the spectrum of medical care. Unfortunately, a proportion of these patients will develop heart failure. Often, for these patients, mechanical circulatory support (MCS) represents the only available treatment option. While single-ventricle patients currently represent a small proportion of the total number of patients who receive MCS, as the single-ventricle patient population increases, this number will increase as well. Outcomes for these complex single-ventricle patients who require MCS has begun to be evaluated. When considering the entire population, survival to hospital discharge is 30-50%, though this must be considered with the significant heterogeneity of the single-ventricle patient population. Patients with a single-ventricle have unique anatomy, mechanisms of failure, indications for MCS and the type of support utilized. This has made the interpretation and the generalizability of the limited available data difficult. It is likely that some subsets will have a significantly worse prognosis and others a better one. Unfortunately, with these limited data, indications of a favorable or poor outcome have not yet been elucidated. Though currently, a database has been constructed to address this issue. While the outcomes for these complex patients is unclear, at least in some situations, they are poor. However, significant advances may provide improvements going forward, including new devices, computer simulations and 3D printed models. The most important factor, however, will be the increased experience gained by the heart failure team to improve patient selection, timing, device and configuration selection and operative approach.

Anomalous Systemic Artery to the Left Lower Lobe: Literature Review and a New Surgical Technique.

Anomalous systemic arterial supply to the basal segments of the left lower lobe without coexisting pulmonary artery connection is a rare anomaly. Most feel treatment is necessary; however, the ideal strategy is unclear. Treatments described include embolization, pulmonary resection, or anastomosis to the native pulmonary artery. We recently encountered an infant with this anomaly and present a literature review summarizing all recent reports. Additionally, we describe a novel surgical technique to create a tension-free anastomosis utilizing segmental aortic translocation that we employed in our patient due to a large distance between the anomalous vessel and native left pulmonary artery.

TGF-α equalizes age disparities in stem cell-mediated cardioprotection.

BACKGROUND: Neonatal mesenchymal stem cells exhibit less cardioprotective potential than their adult counterparts. Transforming growth factor-α (TGF-α) has been shown to stimulate adult stem cell VEGF production, however, it remains unknown whether it may augment neonatal stem cell paracrine function. We hypothesized that TGF-α would equalize adult and neonatal stem cell paracrine function and cardioprotection during acute ischemia/reperfusion. MATERIALS AND METHODS: Bone marrow mesenchymal stem cells isolated from adult and 2.5 wk-old mice were treated with TGF-α (250 ng/mL) for 24 h. VEGF, HGF, IGF-1, IL-1ß, and IL-6 production were measure in vitro, and cells were infused via an intracoronary route using a model of isolated heart perfusion. RESULTS: TGF-α equalized adult and neonatal stem cell VEGF production but did not affect production of HGF, IGF-1, IL-1ß, or IL-6. ERK, p38 MAPK, and JNK phosphorylation were greater in adult cells in response to TGF-α. Whereas infusion of adult but not neonatal stem cells was associated with improved myocardial functional recovery during reperfusion, infusions of either TGF-α-pretreated cell group were associated with the greatest functional recovery. TGF-α equalizes adult and neonatal mesenchymal stem cell VEGF production and cardioprotection in association with differential regulation of ERK, p38 MAPK, and JNK phosphorylation.

Pretreating mesenchymal stem cells with interleukin-1ß and transforming growth factor-ß synergistically increases vascular endothelial growth factor production and improves mesenchymal stem cell-mediated myocardial protection after acute ischemia.

BACKGROUND: Mesenchymal stem cells (MSCs) improve postischemic myocardial function in part through their secretion of growth factors such as vascular endothelial growth factor (VEGF). Pretreating MSCs with various cytokines or small molecules can improve VEGF secretion and MSC-mediated cardioprotection. However, whether 1 cytokine can potentiate the effect of another cytokine in MSC pretreatment to achieve a synergistic effect on VEGF production and cardioprotection is poorly studied. METHODS: MSCs were treated with interleukin (IL)-1ß and/or transforming growth factor (TGF)-ß1 for 24 hours before experiments. VEGF production was determined by enzyme-linked immunosorbent assay. Isolated hearts from adult male Sprague-Dawley rats were subjected to 15 minutes of equilibration, 25 minutes of ischemia, and 40 minutes reperfusion. Hearts (n = 5-7 per group) were randomly infused with vehicle, untreated MSCs, or MSCs pretreated with IL-1ß and/or TGF-ß1. Specific inhibitors were used to delineate the roles of p38 mitogen-activated protein kinase (MAPK) and SMAD3 in IL-1ß- and TGF-ß1-mediated stimulation of MSCs. RESULTS: MSCs cotreated with IL-1ß and TGF-ß1 exhibited synergistically increased VEGF secretion, and they greatly improved postischemic myocardial functional recovery. Ablation of p38 MAPK and SMAD3 activation with specific inhibitors negated both IL-1ß- and TGF-ß1-mediated VEGF production in MSCs and the ability of these pretreated MSCs to improve myocardial recovery after ischemia. CONCLUSION: Pretreating MSCs with 2 cytokines may be useful to fully realize the potential of cell-based therapies for ischemic tissues.

Transforming growth factor-α enhances stem cell-mediated postischemic myocardial protection.

BACKGROUND: Transforming growth factor-α (TGF-α) has been shown to augment mesenchymal stem cell-mediated cardioprotection during acute ischemia and reperfusion in isolated heart models. To determine whether this pretreatment strategy would be effective in vivo, we hypothesized that the intramyocardial injection of mesenchymal stem cells pretreated with TGF-α after coronary artery ligation would confer greater preservation of cardiac function, reduction in infarct size, and reduction myocardial inflammation. METHODS: Sprague-Dawley rats underwent left anterior descending coronary artery ligation. Ischemic border zones were injected 30 minutes later with vehicle (n = 11), 1 million mesenchymal stem cells (n = 9), or mesenchymal stem cells pretreated with TGF-α (250 ng/mL for 24 hours; n = 10). Cardiac function was assessed by echocardiography at 7 and 28 days after ligation. Infarct size was measured using triphenyltetrazolium chloride. Ischemic border zone cytokine expression was measured 30 days after infarction. RESULTS: Myocardial function after ligation was greatest in hearts injected with cells pretreated with TGF-α in association with reduced ventricular remodeling and infarct size compared with vehicle-injected hearts. Myocardial interleukin 1ß, interleukin 6, and TNF-α concentrations were lower, and Bcl-2 expression was higher, in hearts injected with either cell type. Vascular endothelial growth factor and matrix metalloproteinase-2 expression were highest in hearts that received pretreated cells. CONCLUSIONS: Intramyocardial injection of mesenchymal stem cells pretreated with TGF-α further protects cardiac function and reduces infarct size compared with injection of untreated cells. Pretreating donor cells with TGF-α may be useful for enhancing cell-based therapies for myocardial ischemia.

Pretreatment with intracoronary mimosine improves postischemic myocardial functional recovery.

BACKGROUND: Cytoprotective growth factors such as vascular endothelial growth factor (VEGF) play important roles in myocardial protection from ischemia/reperfusion (I/R). Accumulating evidence suggests that the hypoxia-inducible factor 1 (HIF-1) pathway is a key regulator of VEGF production in the setting of I/R. The prolyl hydroxylase inhibitor mimosine can increase VEGF production through the HIF-1 pathway. We hypothesized that infusion of preischemic intracoronary mimosine would improve myocardial functional recovery after I/R. METHODS: Isolated male rat hearts were subjected to 15 minutes of equilibration, 25 minutes of ischemia, and 40 minutes of reperfusion. Immediately prior to ischemia, ischemic hearts received intracoronary infusions of vehicle or solutions of 0.3, 3, or 30 µM mimosine. Myocardial function was recorded throughout the experiments. Functional data were analyzed with two-way analysis of variance adjusted with the Bonferroni correction. RESULTS: Preischemic myocardial function was equivalent. All hearts had significant reductions in function at the beginning of reperfusion. Hearts treated with 0.3 or 3 µM mimosine infusions exhibited greater recovery of left ventricular developed pressure compared to vehicle. The maximal positive value of the first derivative of pressure (+dP/dt) was greater in hearts treated with 0.3 µM mimosine compared to hearts treated with vehicle. No differences were observed in recovery of end-diastolic pressure or the maximal negative value of the first derivative of pressure (-dP/dt). CONCLUSION: Preischemic intracoronary mimosine infusion improves myocardial functional recovery after I/R.

Systemic pretreatment with dimethyloxalylglycine increases myocardial HIF-1α and VEGF production and improves functional recovery after acute ischemia/reperfusion.

BACKGROUND: Stem cells protect the heart from ischemic damage in part by the release of cytoprotective growth factors, particularly vascular endothelial growth factor (VEGF). Production of VEGF is regulated in part by levels of the transcription factor hypoxia inducible factor 1-α (HIF-1α). Dimethyloxalylglycine (DMOG) prevents the deactivation of HIF-1α and increases VEGF production. However, the effects of systemic DMOG treatment on myocardial tolerance for ischemia are unknown. We hypothesized that systemic pretreatment with DMOG would improve myocardial ischemic tolerance. METHODS: To study this hypothesis, adult male rats were randomly given an intraperitoneal injection of DMOG (40 mg/kg in 1 mL saline, n = 5) or saline (1 mL, n = 6) 24 h before cardiectomy and isolated heart perfusion. All hearts were subjected to 15 min equilibration, 25 min ischemia and 40 min reperfusion. Myocardial function was continuously monitored. Following reperfusion, myocardial homogenates were analyzed for HIF-1α and VEGF production. RESULTS: We observed that hearts in the DMOG group exhibited greater recovery of left ventricular developed pressure LVDP, +dP/dt and -dP/dt. Myocardial HIF-1α and VEGF levels were increased by DMOG therapy. CONCLUSION: In conclusion, systemic pretreatment with DMOG augments post-ischemic myocardial functional recovery through increased HIF-1α levels and greater VEGF production.