Results of international assistance for a paediatric heart surgery programme in a single Ukrainian centre.

BACKGROUND: Surgery for CHD has been slow to develop in parts of the former Soviet Union. The impact of an 8-year surgical assistance programme between an emerging centre and a multi-disciplinary international team that comprised healthcare professionals from developed cardiac programmes is analysed and presented.Material and methodsThe international paediatric assistance programme included five main components - intermittent clinical visits to the site annually, medical education, biomedical engineering support, nurse empowerment, and team-based practice development. Data were analysed from visiting teams and local databases before and since commencement of assistance in 2007 (era A: 2000-2007; era B: 2008-2015). The following variables were compared between periods: annual case volume, operative mortality, case complexity based on Risk Adjustment for Congenital Heart Surgery (RACHS-1), and RACHS-adjusted standardised mortality ratio. RESULTS: A total of 154 RACHS-classifiable operations were performed during era A, with a mean annual case volume by local surgeons of 19.3 at 95% confidence interval 14.3-24.2, with an operative mortality of 4.6% and a standardised mortality ratio of 2.1. In era B, surgical volume increased to a mean of 103.1 annual cases (95% confidence interval 69.1-137.2, p<0.0001). There was a non-significant (p=0.84) increase in operative mortality (5.7%), but a decrease in standardised mortality ratio (1.2) owing to an increase in case complexity. In era B, the proportion of local surgeon-led surgeries during visits from the international team increased from 0% (0/27) in 2008 to 98% (58/59) in the final year of analysis. CONCLUSIONS: The model of assistance described in this report led to improved adjusted mortality, increased case volume, complexity, and independent operating skills.

Dietary Sodium Restriction Reduces Arterial Stiffness, Vascular TGF-ß-Dependent Fibrosis and Marinobufagenin in Young Normotensive Rats.

High salt (HS) intake stimulates the production of marinobufagenin (MBG), an endogenous steroidal Na/K-ATPase ligand, which activates profibrotic signaling. HS is accompanied by a blood pressure (BP) increase in salt-sensitive hypertension, but not in normotensive animals. Here, we investigated whether HS stimulates MBG production and activates transforming growth factor-beta (TGF-ß) profibrotic signaling in young normotensive rats, and whether these changes can be reversed by reducing salt to a normal salt (NS) level. Three-month old male Sprague⁻Dawley rats received NS for 4 and 8 weeks (0.5% NaCl; NS4 and NS8), or HS for 4 and 8 weeks (4% NaCl; HS4 and HS8), or HS for 4 weeks followed by NS for 4 weeks (HS4/NS4), n = 8/group. Systolic BP (SBP), pulse wave velocity (PWV), MBG excretion, aortic collagen 1α2, collagen 4α1 and TGF-ß, Smad2, Smad3, Fli-1 mRNA, and total collagen abundance were measured at baseline (BL), and on weeks 4 and 8. Statistical analysis was performed using one-way ANOVA. SBP was not affected by HS (125 ± 5 and 126 ± 6 vs. 128 ± 7 mmHg, HS4 and HS8 vs. BL, p > 0.05). HS increased MBG (164 ± 19 vs. 103 ± 19 pmol/24 h/kg, HS4 vs. BL, p < 0.05) and PWV (3.7 ± 0.2 vs. 2.7 ± 0.2 m/s, HS4 vs. NS4, p < 0.05). HS8 was associated with a further increase in MBG and PWV, with an increase in aortic Col1a2 80%), Col4a1 (50%), Tgfb1 (30%), Smad2 (30%) and Smad3 (45%) mRNAs, and aortic wall collagen (180%) vs. NS8 (all p < 0.05). NS following HS downregulated HS-induced factors: in HS4/NS4, the MBG level was 91 ± 12 pmol/24 h/kg (twofold lower than HS8, p < 0.01), PWV was 3.7 ± 0.3 vs. 4.7 ± 0.2 m/s (HS4/NS4 vs. HS8, p < 0.05), aortic wall Tgfb1, Col1a2, Col4a1, Smad2, Smad3 mRNAs, and collagen abundance were reversed by salt reduction to the BL levels (p < 0.05). HS was associated with an activation of TGF-ß signaling, aortic fibrosis and aortic stiffness accompanied by an MBG increase in the absence of SBP changes in young normotensive rats. The reduction of dietary salt following HS decreased MBG, PWV, aortic wall collagen and TGF-ß. Thus, HS-induced aortic stiffness in normotensive animals occurred in the context of elevated MBG, which may activate SMAD-dependent TGF-ß pro-fibrotic signaling. This data suggests that a decrease in salt consumption could help to restore aortic elasticity and diminish the risk of cardiovascular disease by reducing the production of the pro-fibrotic factor MBG.

Recombinant phenotyping of cytomegalovirus UL54 mutations that emerged during cell passages in the presence of either ganciclovir or foscarnet.

Selection of human cytomegalovirus variants in the presence of ganciclovir or foscarnet led to 18 DNA polymerase mutations, 14 of which had not been previously studied. Using bacterial artificial chromosome technology, each of these mutations was individually transferred into the genome of a reference strain. Following reconstitution of infectious viral stocks, each mutant was assessed for its drug susceptibility and growth kinetics in cell culture. Computer-assisted three-dimensional (3D) modeling of the polymerase was also used to position each of the mutations in one of four proposed structural domains and to predict their influence on structural stability of the protein. Among the 10 DNA polymerase mutations selected with ganciclovir, 7 (P488R, C539R, L545S, V787L, V812L, P829S, and L862F) were associated with ganciclovir resistance, whereas 2 (F595I and V946L) conferred only foscarnet resistance. Among the eight mutations selected with foscarnet, only two (T552N and S585A) conferred foscarnet resistance, whereas four (N408D, K500N, L802V, and L957F) had an impact on ganciclovir susceptibility. Surprisingly, the combination of mutations, some of which were not associated with resistance for a specific antiviral, resulted in increasing resistance effects. 3D modeling suggested that none of the mutated residues were directly involved in the polymerase catalytic site but rather had an influence on drug susceptibility by modifying the structural flexibility of the protein. Our study significantly adds to the number of DNA polymerase mutations conferring in vitro drug resistance and emphasizes the point that evaluation of individual mutations may not accurately reflect the phenotype conferred by multiple mutations.

Three-dimensional modeling of cytomegalovirus DNA polymerase and preliminary analysis of drug resistance.

Cytomegalovirus (CMV) is the leading cause of congenital infection and a frequent opportunistic agent in immunocompromised hosts such as transplant recipients and AIDS patients. CMV DNA polymerase, a member of the polymerase B family, is the primary target of all available antivirals (ganciclovir, cidofovir, and foscarnet) and certain variations of this enzyme could lead to drug resistance. However, understanding the drug resistance mechanisms at the atomic level is hampered by the lack of its three-dimensional (3D) structure. In the present work, 3D models of two different conformations (closed and open) for CMV DNA polymerase have been built based on the crystal structures of bacteriophage RB69 DNA polymerase (a member of the polymerase B family) by using the 3D-Jury Meta server and the program MODELLER. Most of the variations on CMV DNA polymerase pertinent to ganciclovir/cidofovir and foscarnet resistance can be explained well based on the open and closed conformation models, respectively. These results constitute a first step towards facilitating our understanding of drug resistance mechanisms for CMV and the interpretation of novel viral mutations.

Novel Technique to Evaluate Pulmonary Vascular Resistance in a Patient With Aortopulmonary Window.

We report a case of a 15-month-old female presenting with a large aortopulmonary window during a medical mission. The optimal surgical correction for this patient would be based on an estimation of her pulmonary vascular reactivity. This report details the use of antegrade/retrograde flow ratios using Doppler measurements in the proximal descending aorta at baseline and while receiving 100% oxygen. A large increase in the proportion of retrograde flow under the 100% oxygen condition suggested a reactive pulmonary vascular bed. She underwent a complete repair with patch closure of the aortopulmonary window. A postoperative echocardiographic assessment showed near normal right ventricular pressures.

Use of platelet gel and its effects on infection in cardiac surgery.

The use of plasmapheresis in cardiac surgery has failed to show an unequivocal benefit. However, the further processing of plasmapheresed blood to obtain a platelet-rich concentrate, termed platelet gel, may reduce patient susceptibility to infection through poorly understood mechanisms related to a combination of platelets, white blood cell content, and expedited wound healing. The purpose of the study was to retrospectively evaluate the incidence wound infections in patients undergoing cardiac surgery. Platelet gel (PG) patients (n = 382) received topical administration of a mixture of platelet concentrated plasma, 10% calcium chloride (5 mL), and bovine thrombin (5000 units). A control group (NoPG, n = 948) operated on concurrently with the treatment group did not receive PG, but otherwise received similar wound care. A historical control (HC, n = 929) included patients operated on before the availability of PG. After Institutional Review Board approval, 20 factors reported in the literature to predispose individuals for increased infection were recorded along with infections classified either as superficial or deep sternal according to the Society of Thoracic Surgeon criteria. All data were obtained from our institutional contribution to the Society of Thoracic Surgeon database. All adult (>19 years of age) patients undergoing cardiac surgery at our institution between October 2002 and June 2005 were included in this study (n = 2259). The incidence of superficial infection was significantly lower in the PG group (0.3%) compared both with the NoPG (1.8%) and HC (1.5%) groups (p < .05). There was a similar relationship found when comparing deep sternal wound infections (PG, 0.0% vs. NoPG, 1.5%; p < .029 and PG vs. HC, 1.7%;p < .01). In conclusion, the application of PG in patients undergoing cardiac surgery seems to confer a level of protection against infection, although the mechanisms of action remain to be elucidated.

Improved outcomes during cardiac surgery: a multifactorial enhancement of cardiopulmonary bypass techniques.

Patients presenting for cardiac surgery with cardiopulmonary bypass (CPB) are more likely to have pre-existing comorbidities, which has resulted in a steady increase in the risk associated with CPB. The resulting challenge has mandated the optimization of perfusion care. The purpose of this study was to retrospectively evaluate the impact of a number of simultaneous, evidence based perfusion care changes on patient outcome. After Institutional Review Board approval, two groups of patients were compared. The control group (n = 317) included all patients undergoing CPB in a 12-month period preceding a multifaceted change in perfusion techniques. The treatment group (n = 259) included all patients undergoing CPB in the 12-month period after the changes, which included the incorporation of updated continuous blood gas monitoring, biocompatible circuitry, updated centrifugal blood propulsion, continuous autotransfusion technology, new generation myocardial protection instrumentation, plasmapheresis, topical platelet gel application, excluding hetastarch while increasing the use of albumin, viscoelastographic coagulation monitoring, and implementing a quantitative quality improvement program. After univariate analysis, propensity scoring and multiple conditional logistical regression were used to control for demographic, preoperative, operative, and postoperative parameters. Results of the primary endpoints revealed a lower mortality rate in the treatment group (4% vs. 9% [95% confidence interval 1.33, 7.72], p = 0.009), lower transfusion rate (51% vs. 59% [1.00, 2.11], p = 0.048), and lower complication rate (55% vs. 65% [1.06,2.19], p = 0.025) despite having similar predicted mortality (11 [2,22] vs. 11[3,22], p = NS) and other preoperative and operative parameters. The lower mortality rate was concurrent with a trend towards a lower incidence of complications, consistent with the differences in primary outcomes. In conclusion, the patients treated after the implementation of a multifactorial improvement plan using evidence based changes in CPB care had decreased complication and mortality rates.

Use of the Quest Myocardial Protection System (MPS) for modified ultrafiltration during pediatric cardiac surgery.

Modified ultrafiltration generally is considered a standard of care for treating children undergoing cardiopulmonary bypass for congenital heat surgery. Different methods, incorporating a variety of devices and technologies, have been described. The present report describes a technique of modified ultrafiltration using arterial-venous flow with the Quest Myocardial Protection System (MPS).

Discordant phenotypes and genotypes of cytomegalovirus (CMV) in patients with AIDS and relapsing CMV retinitis.

OBJECTIVE: To investigate the correlation between genotypic studies performed on blood leukocytes and phenotypic results obtained from the corresponding blood viral isolates in AIDS patients with relapsing cytomegalovirus (CMV) retinitis. METHODS: Sequential blood samples were collected from patients failing intravenous or oral ganciclovir therapy. The CMV UL97 gene was amplified directly from leukocyte DNA extracts for assessing the presence of viral mutations using restriction fragment length polymorphism analysis and direct sequencing. Positive viral cultures from the same blood samples were also analyzed for their susceptibility to ganciclovir and their UL97 genotype was determined. RESULTS: Discordant CMV genotypes between the clinical specimen and the viral culture were found in at least one blood sample from three of the four patients with relapsing CMV retinitis. Furthermore, some UL97 mutations at known resistance codons (592, 594) were associated with a drug-susceptible phenotype. In all four cases, genotypic analyses of blood samples better correlated with clinical progression than phenotypic analyses of viral cultures. CONCLUSIONS: The presence of mixed viral populations in blood samples of AIDS patients and the potential selection bias introduced by susceptibility testing may underestimate the real impact of CMV resistance in patients failing antiviral therapy.

Novel use of extracellular matrix graft for creation of pulmonary valved conduit.

We report the use of a commercially available graft material to create a trileaflet pulmonary valved conduit, which was implanted in a 12-year-old girl with mixed aortic valve disease as part of a Ross procedure. The patient presented with severe aortic insufficiency and left ventricular dilatation following balloon valvuloplasty. The patient lives in Ecuador, where most commonly used replacements for the pulmonary valve are either unavailable or unaffordable. Our technique involves the use of porcine small intestinal submucosal extracellular matrix (SIS-ECM), commercially available as CorMatrix ECM (CorMatrix Cardiovascular, Inc, Tallahassee, Florida) to create a trileaflet-valved conduit.

Anomalous left coronary artery from the pulmonary artery: intermediate results of coronary elongation.

A two coronary system is preferred for correcting anomalous left coronary artery from the pulmonary artery (ALCAPA); however, translocation is not always possible. In countries where neonatal arterial switch operations have not been perfected coronary transfer can be difficult. The purpose of this report is to describe the intermediate results using the coronary elongation and translocation technique in developing countries. Records of patients undergoing operation by the International Children's Heart Foundation team were reviewed (April 1993-October 2008) for those undergoing ALCAPA repair. All patients received a 2-D echocardiographic-color Doppler examination prior to discharge and at follow-up. A total of 13 patients were identified, age ranged from 9 days to 41 years. All but one patient were operated upon at one of our affiliate hospitals in Croatia, Belarus, China and Colombia. All patients presented with moderate to severe mitral regurgitation and cardiac failure. Follow-up ranged from six months to 9.5 years postoperatively. Color Doppler showed a patent left coronary artery; echocardiography estimated a normal left ventricular ejection fraction and improved mitral regurgitation in all patients. The technique provides an alternative approach to translocation for ALCAPA in countries where routine neonatal coronary transfer techniques may not be perfected. Intermediate results are comparable to translocation.

Role of helix P of the human cytomegalovirus DNA polymerase in resistance and hypersusceptibility to the antiviral drug foscarnet.

Mutations in the human cytomegalovirus DNA polymerase (UL54) can not only decrease but also increase susceptibility to the pyrophosphate (PP(i)) analogue foscarnet. The proximity of L802M, which confers resistance, and K805Q, which confers hypersusceptibility, suggests a possible unifying mechanism that affects drug susceptibility in one direction or the other. We found that the polymerase activities of L802M- and K805Q-containing mutant enzymes were literally indistinguishable from that of wild-type UL54; however, susceptibility to foscarnet was decreased or increased, respectively. A comparison with the crystal structure model of the related RB69 polymerase suggests that L802 and K805 are located in the conserved alpha-helix P that is implicated in nucleotide binding. Although L802 and K805 do not appear to make direct contacts with the incoming nucleotide, it is conceivable that changes at these residues could exert their effects through the adjacent, highly conserved amino acids Q807 and/or K811. Our data show that a K811A substitution in UL54 causes reductions in rates of nucleotide incorporation. The activity of the Q807A mutant is only marginally affected, while this enzyme shows relatively high levels of resistance to foscarnet. Based on these data, we suggest that L802M exerts its effects through subtle structural changes in alpha-helix P that affect the precise positioning of Q807 and, in turn, its presumptive involvement in binding of foscarnet. In contrast, the removal of a positive charge associated with the K805Q change may facilitate access or increase affinity to the adjacent Q807.

Right aortic coarctation and ventricular septal defect: an unusual cause of tracheal compression in infancy.

OBJECTIVE: Acyanotic congenital heart diseases may occasionally present with tracheobronchial obstruction. Increased pulmonary blood flow against a high-resistance pulmonary bed may create significant pulmonary artery dilation. METHODS: We report an unusual case of ventricular septal defect and right aortic arch coarctation, complicated with distal tracheal compression secondary to a pincer effect created by a right aortic arch and a massively dilated pulmonary artery. RESULTS: High index of suspicion is required to anticipate tracheobronchial compression in acyanotic congenital heart diseases. CONCLUSION: Fiberoptic bronchoscopy is an invaluable tool to assess for tracheal compression relief following surgical repair and to identify tracheomalacia prior to extubation.

Characterization of human cytomegalovirus (HCMV) UL97 mutations found in a valganciclovir/oral ganciclovir prophylactic trial by use of a bacterial artificial chromosome containing the HCMV genome.

A method based on manipulation of the human cytomegalovirus genome in a bacterial artificial chromosome was developed to determine the role played by 6 UL97 mutations of unknown significance. These mutations were found in blood samples from solid-organ transplant recipients in a trial comparing valganciclovir and oral ganciclovir prophylaxis. Recombinant viruses containing UL97 mutations P405L, A427V, M550I, A582V, Y617H, and A674T were generated in a bacterial system. Viral stocks were subsequently reconstituted in human fibroblasts, and ganciclovir susceptibilities were tested using a plaque-reduction assay. All recombinant viruses containing these unknown mutations were found to be susceptible to ganciclovir.

Analysis of cytomegalovirus DNA polymerase (UL54) mutations in solid organ transplant patients receiving valganciclovir or ganciclovir prophylaxis.

We previously reported the absence of CMV UL97 (kinase) gene resistance mutations up to 12 months post-transplant following 100 days of valganciclovir prophylaxis, and a low incidence of resistance mutations following 100 days of oral ganciclovir prophylaxis in a prospective multicenter study in solid organ transplant recipients excluding lung transplants. Herein, we report UL54 (DNA polymerase) gene sequencing results for all patients with previous UL97 PCR-positive samples (n = 99) in our study. One UL54 resistance mutation (L545S known to confer ganciclovir and cidofovir resistance) was detected in a routine day-100 sample from an asymptomatic patient who received oral ganciclovir. Notably, this CMV UL54 mutation occurred in the absence of a UL97 mutation. Additionally, new UL54 variants were observed. Thus, emergence of CMV UL54 mutations in the absence of UL97 mutations is a rare but possible event that is not necessarily associated with detrimental clinical outcome in solid organ transplant recipients.

Coagulation management of a patient with factor V Leiden mutation, lupus anticoagulant, and activated protein C resistance: a case report.

Although patients undergoing cardiac surgery often present with diverse comorbidities, those with coagulation derangements are especially challenging. The present report describes the management of a patient who presented with a Factor V Leiden mutation, lupus anticoagulant, and acquired activated protein C resistance. A 42-year-old female presented with acute shortness of breath and chest pain. She was otherwise healthy 1 month prior to admission when she presented with dysfunctional uterine bleeding, resulting in the transfusion of three units of packed red blood cells. Coagulation evaluation revealed that the patient had lupus anticoagulant, factor V Leiden mutation and an activated protein C resistance. The patient presented with an acute myocardial infarction and was found to have 90% stenosis of her left main coronary artery, moderate mitral and tricuspid regurgitation, and a left ventricular ejection fraction of 25%. An emergent off-pump coronary artery bypass procedure with placement of a vein graft to the left anterior descending artery was completed. Intraoperative thrombophilia was encountered as evidenced by both an elevated thromboelastograph coagulation index (+3.6) and an acquired antithrombin-III deficiency. Postoperatively, the patient was placed on low molecular weight heparin, but developed heparin-induced thrombocytopenia and was switched to a direct thrombin inhibitor, argatroban. The following case report describes the coagulation management of this patient from the time of admission to discharge 43 days later, and the unique challenges this combination of hemostatic defects present to the clinicians.

Cytomegalovirus (CMV) glycoprotein B genotypes and response to antiviral therapy, in solid-organ-transplant recipients with CMV disease.

Cytomegalovirus (CMV) can be classified into 4 glycoprotein B (gB) genotypes, on the basis of sequence variation in the UL55 gene. We assessed the effect that CMV gB genotype has on virologic and clinical response to therapy, in 50 solid-organ-transplant recipients with CMV disease. CMV loads were determined at regular intervals after the start of therapy. Genotype results were correlated with CMV-load kinetics in response to therapy with ganciclovir. At the onset of treatment, the distribution of CMV gB genotypes was as follows: gB1, 19/50 (38%); gB2, 9/50 (18%); gB3, 12/50 (24%); gB4, 2/50 (4%); and mixed-genotype infection, 8/50 (16%). Between viral genotype groups, time to clearance of CMV, failure to clear CMV, and calculated CMV-load half-life after the start of therapy were not significantly different. The CMV gB genotype did not affect the rate of disease recurrence or occurrence of tissue-invasive disease. It appears that the gB genotype, which causes CMV disease, does not significantly influence CMV-load kinetics or clinical response to therapy.

Resistance of herpesviruses to antiviral drugs: clinical impacts and molecular mechanisms.

Nucleoside analogues such as acyclovir and ganciclovir have been the mainstay of therapy for alphaherpesviruses (herpes simplex virus (HSV) and varicella-zoster virus (VZV)) and cytomegalovirus (CMV) infections, respectively. Drug-resistant herpesviruses are found relatively frequently in the clinic, almost exclusively among severely immunocompromised patients receiving prolonged antiviral therapy. For instance, close to 10% of patients with AIDS receiving intravenous ganciclovir for 3 months excrete a drug-resistant CMV isolate in their blood or urine and this percentage increases with cumulative drug exposure. Many studies have reported that at least some of the drug-resistant herpesviruses retain their pathogenicity and can be associated with progressive or relapsing disease. Viral mutations conferring resistance to nucleoside analogues have been found in either the drug activating/phosphorylating genes (HSV or VZV thymidine kinase, CMV UL97 kinase) and/or in conserved regions of the viral DNA polymerase. Currently available second line agents for the treatment of herpesvirus infections--the pyrophosphate analogue foscarnet and the acyclic nucleoside phosphonate derivative cidofovir--also inhibit the viral DNA polymerase but are not dependent on prior viral-specific activation. Hence, viral DNA polymerase mutations may lead to a variety of drug resistance patterns which are not totally predictable at the moment due to insufficient information on specific drug binding sites on the polymerase. Although some CMV and HSV DNA polymerase mutants have been found to replicate less efficiently in cell cultures, further research is needed to correlate viral fitness and clinical outcome.

Absence of cytomegalovirus-resistance mutations after valganciclovir prophylaxis, in a prospective multicenter study of solid-organ transplant recipients.

We investigated the emergence of cytomegalovirus (CMV) ganciclovir-resistance mutations in 301 high-risk solid-organ transplant (SOT) recipients after oral prophylaxis, for 100 days, with either valganciclovir or ganciclovir. For patients treated with ganciclovir, the incidence of CMV UL97 mutations was 1.9% (2/103) at the end of prophylaxis and 6.1% (2/33) for patients with suspected CMV disease up to 1 year after transplantation. No resistance mutations were detected in samples from valganciclovir-treated patients. Dual polymerase (UL54) and UL97 resistance mutations were not seen. Valganciclovir was associated with negligible risk of resistance and thus constitutes a useful alternative to ganciclovir prophylaxis for CMV in high-risk SOT recipients.