Activated 4-Factor Prothrombin Complex Concentrate as a Hemostatic Adjunct for Neonatal Cardiac Surgery: A Propensity Score-Matched Cohort Study.

BACKGROUND: Prothrombin complex concentrates are an emerging "off-label" therapy to augment hemostasis after cardiopulmonary bypass (CPB), but data supporting their use for neonatal cardiac surgery are limited. METHODS: We retrospectively reviewed neonates undergoing open heart surgery with first-time sternotomy between May 2014 and December 2018 from a hospital electronic health record database. Neonates who received activated 4-factor prothrombin complex concentrate (a4FPCC) after CPB were propensity score matched (PSM) to neonates who did not receive a4FPCC (control group). The primary efficacy outcome was total volume (mL/kg) of blood products transfused after CPB, including the first 24 hours on the cardiovascular intensive care unit (CVICU). The primary safety outcome was the incidence of 7- and 30-day postoperative thromboembolism. Secondary outcomes included 24 hours postoperative chest tube output, time to extubation, duration of CVICU stay, duration of hospital stay, 30-day mortality, and incidence of acute kidney injury on postoperative day 3. We used linear regression modeling on PSM data for the primary efficacy outcome. For the primary safety outcome, we tested for differences using McNemar test on PSM data. For secondary outcomes, we used linear regression, Fisher exact test, or survival analyses as appropriate, with false discovery rate-adjusted P values. RESULTS: A total of 165 neonates were included in the final data analysis: 86 in the control group and 79 in the a4FPCC group. After PSM, there were 43 patients in the control group and 43 in the a4FPCC group. We found a statistically significant difference in mean total blood products transfused for the a4FPCC group (47.5 mL/kg) compared with the control group (63.7 mL/kg) for PSM patients (adjusted difference, 15.3; 95% CI, 29.4-1.3; P = .032). We did not find a statistically significant difference in 7- or 30-day thromboembolic rate, postoperative chest tube output, time to extubation, incidence of postoperative acute kidney injury (AKI), or 30-day mortality between the groups. The a4FPCC group had a significantly longer length of intensive care unit stay (32.9 vs 13.3 days; adjusted P = .049) and hospital stay (44.6 vs 24.1 days; adjusted P = .049) compared with the control group. CONCLUSIONS: We found that the use of a4FPCC as a hemostatic adjunct for post-CPB bleeding in neonatal cardiac surgery was associated with a decrease in mean total blood products transfused after CPB without an increased rate of 7- or 30-day postoperative thromboembolism. Our findings suggest that a4FPCCs can be considered as part of a hemostasis pathway for refractory bleeding in neonatal cardiac surgery.

Molecular evolutionary analysis of the SM and SNARE vesicle fusion machinery in ciliates shows concurrent expansions in late secretory machinery.

Protists in the phylum Ciliophora possess a complex membrane-trafficking system, including osmoregulatory Contractile Vacuoles and specialized secretory organelles. Molecular cell biological investigations in Tetrahymena thermophila have identified components of the protein machinery associated with the secretory organelles, mucocysts. The Qa-SNARE Syn7lp plays a role in mucocyst biogenesis as do subunits of the CORVET tethering complex (specifically Vps8). Indeed, Tetrahymena thermophila possesses expanded gene complements of several CORVET components, including Vps33 which is also a Sec1/Munc18 (SM) protein that binds Qa-SNAREs. Moreover, the Qa-SNAREs in Paramecium tetraurelia have been localized to various endomembrane organelles. Here, we use comparative genomics and phylogenetics to determine the evolutionary history of the SM and Qa-SNARE proteins across the Ciliophora. We identify that the last ciliate common ancestor possessed the four SM proteins and six Qa-SNAREs common to eukaryotes, including the uncommonly retained Syntaxin 17. We furthermore identify independent expansion of these protein families in several ciliate classes, including concurrent expansions of the SM protein-Qa SNARE partners Sec1:SynPM in the oligohymenophorean ciliates lineage, consistent with novel Contractile Vacuole specific innovations. Overall, these data are consistent with SM proteins and Qa-SNAREs being a common set of components for endomembrane modulation in the ciliates.

Taxonomic resolution of Stylonychia notophora (Alveolata, Ciliophora, Hypotricha) sensu Sapra and Dass 1970 using an integrative approach.

The spirotrichean ciliate Stylonychia notophora has previously been recorded in India although the descriptions are lacking in detail. It has been suggested several times that the Indian population, S. notophora sensu Sapra and Dass, 1970 collected along the Delhi stretch of the River Yamuna, is identical to Tetmemena pustulata, but this has never been confirmed due to insufficient data for the former. The present study includes detailed descriptions (classical and molecular) of populations of Tetmemena isolated from six locations along the River Yamuna, India. These include four from the Delhi stretch including that from which Sapra and Dass, 1970 isolated their population of S. notophora. Due to the lack of a sufficiently detailed description, the taxonomic status of S. notophora sensu Sapra and Dass, 1970 was not clear. Comparisons among the populations isolated in the present study with previous descriptions of T. pustulata and S. notophora sensu Sapra and Dass, 1970 show only minor differences in morphometry, morphogenesis and in 18S rDNA sequences. The 18S rDNA sequences of all six populations had 99% similarity to both T. pustulata and S. notophora. These findings support the contention that S. notophora sensu Sapra and Dass, 1970 was misidentified and is a population of T. pustulata. This study supports the need for adopting an integrative approach based on morphological, morphogenetic and molecular data in order to understand species delimitation in ciliated protists.

Fibrinogen Concentrate as an Alternative to Cryoprecipitate in a Postcardiopulmonary Transfusion Algorithm in Infants Undergoing Cardiac Surgery: A Prospective Randomized Controlled Trial.

BACKGROUND: Infants undergoing cardiac surgery are at risk for bleeding and massive transfusion due to an immature coagulation system, complex surgeries, and cardiopulmonary bypass (CPB) effects. Hemodilution from CPB promotes an acquired hypofibrinogenemia that results in impaired fibrin formation, inadequate clot formation, and increased bleeding. In North America, the current standard of care to supplement fibrinogen is cryoprecipitate. An alternative option is the off-label use of fibrinogen concentrate (FC; RiaSTAP; CSL Behring, Marburg, Germany), a purified fibrinogen. Because perioperative allogenic transfusions are associated with increased morbidity and mortality, we sought to determine whether FC would be an acceptable alternative to cryoprecipitate in a post-CPB transfusion algorithm in infants undergoing open-heart surgery. METHODS: We randomized 60 infants (<12 months) undergoing nonemergent cardiac surgery with CPB at 2 tertiary care children's hospitals to receive either cryoprecipitate or FC in a post-CPB transfusion algorithm. Infants underwent a stratified randomization based on institution and surgical complexity. The primary outcome was the difference in number of intraoperative allogenic blood product transfusions. Secondary outcomes included 24-hour chest tube output (CTO), mechanical ventilation time, adverse events (AEs), intensive care unit (ICU) length of stay (LOS), hospital LOS, postoperative thrombosis, and death within 30 days of surgery. The primary analysis followed the intent-to-treat (ITT) principle and was performed using linear regression adjusted for institution and complexity of surgery. A per-protocol (PP) analysis was also performed. RESULTS: Between June 2016 and January 2018, we enrolled 60 patients with complete data available for 25 patients who received cryoprecipitate and 29 patients who received FC. Patients in the cryoprecipitate group (median age: 4 months [2-6 months]) received 5.5 (4.0-7.0) allogeneic blood units in the ITT analysis and 6.0 units (5.0-7.0 units) in the PP analysis. Patients in the FC group (median age: 4 months [2-5]) received 4 units (3.0-5.0 units) in the ITT analysis and 4.0 units (3.0-5.0 units) in the PP analysis. In the adjusted ITT analysis, the FC group received 1.79 units (95% confidence interval [CI], 0.64-2.93; P = .003) less than the cryoprecipitate group. In the adjusted PP analysis, the FC group received 2.67 units (95% CI, 1.75-3.59; P < .001) less than the cryoprecipitate group. There were no significant differences in secondary outcomes or AEs. CONCLUSIONS: Our findings suggest that FC may be considered as an alternative to cryoprecipitate for the treatment of hypofibrinogenemia in infants with bleeding after CPB. Although we found no significant differences between secondary outcomes or AEs, further studies are needed to assess safety.

Symposium Report: International Symposium on Ciliate Biology, India Habitat Centre, New Delhi, India, 04-06 April 2018.

Ciliated protists have attracted wide interest among researchers from the Indian subcontinent in the last few years. An International Symposium on Ciliate Biology (ISCB) 2018 was held on 04-06 April 2018 at the India Habitat Centre, New Delhi, India. The symposium represented a synergy with International Research Coordination Network for Biodiversity of Ciliates (IRCN-BC), an affiliate society of International Society of Protistologists (ISOP). The symposium provided a platform for Indian and International delegates to exchange knowledge, present their latest research findings, and establish collaborations as well as creating a networking opportunity for undergraduate and postgraduate students. Nine foreign delegates from 5 countries and 300 Indian delegates actively participated in the event which included 22 oral and 57 poster presentations.

Role of echocardiography in the assessment of right ventricular function in the pediatric population.

This review article summarizes the use of echocardiography in the evaluation of the right ventricle with special emphasis on pediatric patients. After reading this article, anesthesiologists will develop a better understanding of the anatomy and echocardiographic parameters for hemodynamic and functional assessment of the right ventricle. This knowledge will assist with the perioperative management of patients with cardiopulmonary disorder.

A Prospective Assessment of Optimal Mechanical Ventilation Parameters for Pediatric Catheter Ablation.

Catheter stability, an important factor in ablation success, is affected by ventilation. Optimal ventilation strategies for pediatric catheter ablation are not known. We hypothesized that small tidal volume and positive end-expiratory pressure are associated with reduced ablation catheter movement at annular positions. Subjects aged 5-25 years undergoing ablation for supraventricular tachycardia (SVT) or WPW at two centers from March 2015 to September 2016 were prospectively enrolled and randomized to receive mechanical ventilation with either positive end-expiratory pressure of 5 cm H2O (PEEP) or 0 cm H2O (ZEEP). Movement of the ablation catheter tip at standard annular positions was measured using 3D electroanatomic mapping systems under two conditions: small tidal volume (STV) (3-5 mL/kg) or large TV (LTV) (6-8 mL/kg). 58 subjects (mean age 13.8 years) were enrolled for a total of 266 separate observations of catheter movement. STV ventilation was associated with significantly reduced catheter movement, compared to LTV at all positions (right posteroseptal: 2.5 ± 1.4 vs. 5.2 ± 3.1 mm, p < 0.0001; right lateral: 2.7 ± 1.6 vs. 6.3 ± 3.5 mm, p < 0.0001; left lateral: 1.8 ± 1.0 vs. 4.3 ± 1.9 mm, p < 0.0001). The presence or absence of PEEP had no effect on catheter movement. In multivariable analysis, STV was associated with a 3.1-mm reduction in movement (95% CI 2.6-3.5, p < 0.0001), adjusting for end-expiratory pressure, annular location, and patient size. We conclude that STV ventilation is associated with reduced ablation catheter movement compared to a LTV strategy, independent of PEEP and annular position.

Younger age remains a risk factor for prolonged length of stay after bidirectional cavopulmonary anastomosis.

OBJECTIVE: This study sets out to determine the influence of age at the time of surgery as a risk factor for post-operative length of stay after bidirectional cavopulmonary anastomosis. METHODS: All patients undergoing a Glenn procedure between January 2010 and July 2015 were included in this retrospective cohort study. Demographic data were examined. Standard descriptive statistics was used. A univariable analysis was conducted using the appropriate test based on data distribution. A propensity score for balancing the group difference was included in the multi-variable analysis, which was then completed using predictors from the univariable analysis that achieved significance of p<0.1. RESULTS: Over the study period, 50 patients met the inclusion criteria. Patients were separated into two cohorts of ⩾4 months (28 patients) and <4 months (22 patients). Other than height and weight, the two cohorts were indistinguishable in their pre-operative saturation, medications, catheterisation haemodynamics, atrioventricular valve regurgitation, and ventricular function. After adjusting group differences, younger age was associated with longer post-operative length of hospitalisation - adjusted mean 15 (±2.53) versus 8 (±2.15) days (p=0.03). In a multi-variable regression analysis, in addition to ventricular dysfunction (ß coefficient=8.8, p=0.05), Glenn procedures performed before 4 months were independently associated with longer length of stay (ß coefficient=-6.9, p=0.03). CONCLUSION: We found that Glenn procedures performed after 4 months of age had shorter post-operative length of stay when compared to a younger cohort. These findings suggest that balancing timing of surgery to decrease the inter-stage period should take into consideration differences in post-operative recovery with earlier operations.

Beyond the "Code": A Guide to the Description and Documentation of Biodiversity in Ciliated Protists (Alveolata, Ciliophora).

Recent advances in molecular technology have revolutionized research on all aspects of the biology of organisms, including ciliates, and created unprecedented opportunities for pursuing a more integrative approach to investigations of biodiversity. However, this goal is complicated by large gaps and inconsistencies that still exist in the foundation of basic information about biodiversity of ciliates. The present paper reviews issues relating to the taxonomy of ciliates and presents specific recommendations for best practice in the observation and documentation of their biodiversity. This effort stems from a workshop that explored ways to implement six Grand Challenges proposed by the International Research Coordination Network for Biodiversity of Ciliates (IRCN-BC). As part of its commitment to strengthening the knowledge base that supports research on biodiversity of ciliates, the IRCN-BC proposes to populate The Ciliate Guide, an online database, with biodiversity-related data and metadata to create a resource that will facilitate accurate taxonomic identifications and promote sharing of data.

Genome Mining and Predictive Functional Profiling of Acidophilic Rhizobacterium Pseudomonas fluorescens Pt14.

Pseudomonas fluorescens Pt14 is a non-pathogenic and acidophilic bacterium isolated from acidic soil (pH 4.65). Genome sequencing of strain Pt14 was performed using Single Molecule Real Time (SMRT) sequencing to get insights into unique existence of this strain in acidic environment. Complete genome sequence of this strain revealed a chromosome of 5,841,722 bp having 5354 CDSs and 88 RNAs. Phylogenomic reconstruction based on 16S rRNA gene, Average Nucleotide Identity (ANI) values and marker proteins revealed that strain Pt14 shared a common clade with P. fluorescens strain A506 and strain SS101. ANI value of strain Pt14 in relation to strain A506 was found 99.23% demonstrating a very close sub-species association at genome level. Further, orthology determination among these three phylogenetic neighbors revealed 4726 core proteins. Functional analysis elucidated significantly higher abundance of sulphur metabolism (>1×) which could be one of the reasons for the survival of strain Pt14 under acidic conditions (pH 4.65). Acidophilic bacteria have capability to oxidize sulphur into sulphuric acid which in turn can make the soil acidic and genome-wide analysis of P. fluorescens Pt14 demonstrated that this strain contributes towards making the soil acidic.

Luteimonas tolerans sp. nov., isolated from hexachlorocyclohexane-contaminated soil.

A Gram-stain-negative, aerobic, rod-shaped, non-spore-forming, yellow pigmented bacterial strain (UM1T) was isolated from the hexachlorocyclohexane (HCH)-contaminated dumpsite located at Ummari village in Lucknow, India. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain UM1T belongs to the genus Luteimonas with Luteimonas aestuarii B9T as the closest neighbour (97.2% 16S rRNA gene sequence similarity). The DNA G+C content of strain UM1T was 64.3 mol%. The major polar lipids were diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE) and phosphatidylglycerol (PG). Main fatty acids were iso-C15:0, iso-C11:0, iso-C11:0 3-OH, iso-C17:0 and summed feature 9 (C16:0 10-methyl and/or iso-C17:1ω9c). Ubiquinone (Q-8) was the only respiratory quinone. Spermidine was detected as the major polyamine. The DNA-DNA relatedness value of strain UM1T with respect to its closest neighbour Luteimonas aestuarii B9T was well below 70 % (∼49%). Thus, data obtained from phylogenetic analysis, DNA-DNA hybridization, and chemotaxonomical and biochemical analyses supports classification of strain UM1T as representative of a novel species of the genus Luteimonas, for which the name Luteimonas tolerans sp. nov. is proposed. The type strain is UM1T (=DSM 28473T=MCC 2572T=KCTC 42936T).

Molecular phylogeny of an Indian population of Kleinstyla dorsicirrata (Foissner, 1982) Foissner et al., 2002. comb. nov. (Hypotrichia, Oxytrichidae): an oxytrichid with incomplete dorsal kinety fragmentation.

Kleinstyla dorsicirrata (Foissner, 1982) Foissner et al., 2002. comb. nov. (basionym: Gastrostyla dorsicirrata) is a slightly flexible oxytrichid, measuring about 88-115 × 27-46 µm in life and possesses cortical granules. Kleinstyla dorsicirrata is the only oxytrichid known so far with incompletely fragmented dorsal kinety. Morphological and morphogenetic data recognise K. dorsicirrata as nonstylonychine oxytrichid. Molecular phylogeny of an Indian population was inferred using 18S rRNA gene sequences and was examined with respect to oxytrichids exhibiting variation in dorsal kinety fragmentation. Kleinstyla dorsicirrata clusters with Oxytricha lanceolata; this proximity is quite significant as both show deviation from typical oxytrichid fragmentation of dorsal kinety. Molecular phylogeny of Indian population confirms its nonstylonychine oxytrichid status.

H7N9: A killer in the making or a false alarm?

Influenza virus remains one of the most important disease-causing viruses owing to its high adaptability and even higher contagious nature. Thus, it poses a constant threat of pandemic, engulfing a large population within the smallest possible time interval. A similar threat was anticipated with the identification of the novel H7N9 virus in China on 30 March 2013. Detection of transmission of the virus between humans has caused a stir with the identification of family clusters along with sporadic infections all across China. In this review we analyze the potential of the novel H7N9 virus as a probable cause of a pandemic and the possible consequences thereof.

SPINE20 recommendations 2023: One Earth, one family, one future WITHOUT spine DISABILITY.

Introduction: The purpose is to report on the fourth set of recommendations developed by SPINE20 to advocate for evidence-based spine care globally under the theme of "One Earth, One Family, One Future WITHOUT Spine DISABILITY". Research question: Not applicable. Material and methods: Recommendations were developed and refined through two modified Delphi processes with international, multi-professional panels. Results: Seven recommendations were delivered to the G20 countries calling them to:-establish, prioritize and implement accessible National Spine Care Programs to improve spine care and health outcomes.-eliminate structural barriers to accessing timely rehabilitation for spinal disorders to reduce poverty.-implement cost-effective, evidence-based practice for digital transformation in spine care, to deliver self-management and prevention, evaluate practice and measure outcomes.-monitor and reduce safety lapses in primary care including missed diagnoses of serious spine pathologies and risk factors for spinal disability and chronicity.-develop, implement and evaluate standardization processes for spine care delivery systems tailored to individual and population health needs.-ensure accessible and affordable quality care to persons with spine disorders, injuries and related disabilities throughout the lifespan.-promote and facilitate healthy lifestyle choices (including physical activity, nutrition, smoking cessation) to improve spine wellness and health. Discussion and conclusion: SPINE20 proposes that focusing on the recommendations would facilitate equitable access to health systems, affordable spine care delivered by a competent healthcare workforce, and education of persons with spine disorders, which will contribute to reducing spine disability, associated poverty, and increase productivity of the G20 nations.

Role of transesophageal echocardiography in the management of pediatric patients with congenital heart disease.

Transesophageal echocardiography (TEE) has become a critical diagnostic and perioperative management tool for patients with congenital heart disease (CHD) undergoing cardiac and noncardiac surgical procedures. This review highlights the role of TEE in routine management of pediatric cardiac patient population with focus on indications, views, applications and technological advances.

Spatial variation in ciliate communities with respect to water quality in the Delhi NCR stretch of River Yamuna, India.

The River Yamuna emerges from Saptarishi Kund, Yamunotri and merge with River Ganges at Allahabad, India. Anthropogenic stress has affected the water quality of the river Yamuna drastically in the stretch traversing Delhi and its satellite towns (National Capital Region, NCR). In the present study, effect of water quality on the microbial life in the River Yamuna was analyzed using ciliate communities (Protista, Ciliophora) as bio-indicators. Water samples were collected from six sampling sites chosen according to the levels of pollution along the river and water quality was analysed using standard physicochemical factors. As the river traverses Delhi NCR, water quality deteriorates considerably as indicated by the Water Quality Index at the selected sampling sites. Seventy-four ciliate species representing nine classes were recorded. Based on the Shannon diversity index, maximum species diversity was found at the point where the river enters Delhi. The saprobity index showed the river water was beta-mesosaprobic when the river enters Delhi and alpha-mesosaprobic at downstream sites after the first major drain outfall. Significant relationship between the spatial variation in ciliate communities and abiotic parameters indicate that ciliates can be used as effective bioindicators of pollution in the River Yamuna.

Perioperative complications in children with pulmonary hypertension undergoing general anesthesia with ketamine.

BACKGROUND: Pulmonary arterial hypertension (PAH) is associated with significant perioperative risk for major complications in children, including pulmonary hypertensive crisis and cardiac arrest. Uncertainty remains about the safety of ketamine anesthesia in this patient population. AIM: Retrospectively review the medical records of children with PAH to ascertain the nature and frequency of peri-procedural complications and to determine whether ketamine administration was associated with peri-procedural complications. METHODS: Children with PAH (mean pulmonary artery pressure > or =25 mmHg and pulmonary vascular resistance index > or =3 Wood units) who underwent general anesthesia for procedures during a 6-year period (2002-2008) were enrolled. Details about the patient, PAH, procedure, anesthetic and postprocedural course were noted, including adverse events during or within 48 h of the procedure. Complication rates were reported per procedure. Association between ketamine and peri-procedural complications was tested. RESULTS: Sixty-eight children (median age 7.3 year, median weight 22 kg) underwent 192 procedures. Severity of PAH was mild (23%), moderate (37%), and severe (40%). Procedures undertaken were major surgery (n = 20), minor surgery (n = 27), cardiac catheterization (n = 128) and nonsurgical procedures (n = 17). Ketamine was administered during 149 procedures. Twenty minor and nine major complications were noted. Incidence of cardiac arrest was 0.78% for cardiac catheterization procedures, 10% for major surgical procedures and 1.6% for all procedures. There was no procedure-related mortality. Ketamine administration was not associated with increased complications. CONCLUSIONS: Ketamine appears to be a safe anesthetic option for children with PAH. We report rates for cardiopulmonary resuscitation and mortality that are more favorable than those previously reported.

Notohymena saprai sp. nov, a new oxytrichid ciliate (Protozoa, Ciliophora) from the Valley of Flowers, a Himalayan bioreserve region; description and morphogenesis of the new species.

A new oxytrichid ciliate Notohymena saprai sp. nov was isolated from the Valley of Flowers, an isolated bioreserve in the upper Himalayas. The ciliate was found in the soil samples collected from the peripheral areas of the flowering region of the valley which is covered with permafrost for nearly eight months in a year. Cells were excysted from the soil samples by the non-flooded petridish method. Species identification was performed by observations on live and silver-impregnated cells. Notohymena saprai sp. nov is highly flexible, measures 152 × 49 µm and shows abundant presence of dark green sub-pellicular granules. The species is distinct by virtue of its new combination of morphometric and developmental characters. Prominent distinguishing features of the new species are its relative large size and presence of four macronuclei (other species of this genus have two macronuclei). The study also reports morphogenetic peculiarities which separate it from the other known species of the genus.

Management of a Pediatric Patient With a Left Ventricular Assist Device and Symptomatic Acquired von Willebrand Syndrome Presenting for Orthotopic Heart Transplant.

We present the successful perioperative management of an 11-year-old patient presenting for heart transplant with a left ventricular assist device, symptomatic acquired von Willebrand syndrome, and recent preoperative intracranial hemorrhage. A brief review of the pathophysiology of acquired von Willebrand syndrome is included. As the number of pediatric patients supported with ventricular assist devices continues to increase, the management of symptomatic acquired von Willebrand syndrome during the perioperative period is an important consideration for anesthesiologists.

Left ventricular retraining in corrected transposition: Relationship between pressure and mass.

BACKGROUND: A subset of patients with corrected transposition of the great arteries (CC-TGA) will require left ventricular (LV) retraining before undergoing a double-switch procedure. LV retraining results in an immediate increase in LV pressure but not in LV mass. The purpose of this study was to evaluate the relationship between LV pressure and mass during LV retraining. METHODS: This was a retrospective review of 36 patients with CC-TGA who were enrolled in LV retraining. The median age at enrollment was 12 months. The majority (82%) had an Ebstenoid tricuspid valve or moderate to severe tricuspid valve regurgitation before pulmonary artery banding. RESULTS: Twenty-seven of the 36 patients underwent LV retraining and a double switch, including 14 patients with a single pulmonary artery band (PAB), 12 patients with 2 PABs, and 1 patient with 3 PABs. There was no early or late mortality associated with these procedures. Ninety percent of the patients demonstrated a linear relationship between LV pressure and mass; however, 3 patients (10%) demonstrated a different LV retraining pattern characterized by excess LV mass compared to LV pressure. Two of these 3 patients are LV retraining failures, whereas the third patient did undergo a double switch. CONCLUSIONS: The data show that the majority of patients enrolled in LV retraining have a predictable relationship between LV mass and pressure. A minority demonstrate an excess accrual of mass with respect to pressure load. These results suggest there may be an important distinction between normal and pathological hypertrophy during the LV retraining process.