A unidirectional mapping of ICD-8 to ICD-10 codes, for harmonized longitudinal analysis of diseases

Periodic revisions of the international classification of diseases (ICD) ensure that the classification reflects new practices and knowledge; however, this complicates retrospective research as diagnoses are coded in different versions. For longitudinal disease trajectory studies, a crosswalk is an essential tool and a comprehensive mapping between ICD-8 and ICD-10 has until now been lacking. In this study, we map all ICD-8 morbidity codes to ICD-10 in the expanded Danish ICD version. We mapped ICD-8 codes to ICD-10, using a many-to-one system inspired by general equivalence mappings such that each ICD-8 code maps to a single ICD-10 code. Each ICD-8 code was manually and unidirectionally mapped to a single ICD-10 code based on medical setting and context. Each match was assigned a score (1 of 4 levels) reflecting the quality of the match and, if applicable, a "flag" signalling choices made in the mapping. We provide the first complete mapping of the 8596 ICD-8 morbidity codes to ICD-10 codes. All Danish ICD-8 codes representing diseases were mapped and 5106 (59.4%) achieved the highest consistency score. Only 334 (3.9%) of the ICD-8 codes received the lowest mapping consistency score. The mapping provides a scaffold for translation of ICD-8 to ICD-10, which enable longitudinal disease studies back to and 1969 in Denmark and to 1965 internationally with further adaption.

Discovery of drug-omics associations in type 2 diabetes with generative deep-learning models

The application of multiple omics technologies in biomedical cohorts has the potential to reveal patient-level disease characteristics and individualized response to treatment. However, the scale and heterogeneous nature of multi-modal data makes integration and inference a non-trivial task. We developed a deep-learning-based framework, multi-omics variational autoencoders (MOVE), to integrate such data and applied it to a cohort of 789 people with newly diagnosed type 2 diabetes with deep multi-omics phenotyping from the DIRECT consortium. Using in silico perturbations, we identified drug-omics associations across the multi-modal datasets for the 20 most prevalent drugs given to people with type 2 diabetes with substantially higher sensitivity than univariate statistical tests. From these, we among others, identified novel associations between metformin and the gut microbiota as well as opposite molecular responses for the two statins, simvastatin and atorvastatin. We used the associations to quantify drug-drug similarities, assess the degree of polypharmacy and conclude that drug effects are distributed across the multi-omics modalities.

Impairment of gut microbial biotin metabolism and host biotin status in severe obesity: effect of biotin and prebiotic supplementation on improved metabolism

OBJECTIVES

Gut microbiota is a key component in obesity and type 2 diabetes, yet mechanisms and metabolites central to this interaction remain unclear. We examined the human gut microbiome's functional composition in healthy metabolic state and the most severe states of obesity and type 2 diabetes within the MetaCardis cohort. We focused on the role of B vitamins and B7/B8 biotin for regulation of host metabolic state, as these vitamins influence both microbial function and host metabolism and inflammation.

DESIGN

We performed metagenomic analyses in 1545 subjects from the MetaCardis cohorts and different murine experiments, including germ-free and antibiotic treated animals, faecal microbiota transfer, bariatric surgery and supplementation with biotin and prebiotics in mice.

RESULTS

Severe obesity is associated with an absolute deficiency in bacterial biotin producers and transporters, whose abundances correlate with host metabolic and inflammatory phenotypes. We found suboptimal circulating biotin levels in severe obesity and altered expression of biotin-associated genes in human adipose tissue. In mice, the absence or depletion of gut microbiota by antibiotics confirmed the microbial contribution to host biotin levels. Bariatric surgery, which improves metabolism and inflammation, associates with increased bacterial biotin producers and improved host systemic biotin in humans and mice. Finally, supplementing high-fat diet-fed mice with fructo-oligosaccharides and biotin improves not only the microbiome diversity, but also the potential of bacterial production of biotin and B vitamins, while limiting weight gain and glycaemic deterioration.

CONCLUSION

Strategies combining biotin and prebiotic supplementation could help prevent the deterioration of metabolic states in severe obesity.

TRIAL REGISTRATION NUMBER

NCT02059538.

Host-microbial co-metabolites modulated by human milk oligosaccharides relate to reduced risk of respiratory tract infections

Human milk oligosaccharides (HMOs) are structurally diverse oligosaccharides present in breast milk, supporting the development of the gut microbiota and immune system. Previously, 2-HMO (2'fucosyllactose, lacto-N-neotetraose) compared to control formula feeding was associated with reduced risk of lower respiratory tract infections (LRTIs), in part linked to lower acetate and higher bifidobacteria proportions. Here, our objective was to gain further insight into additional molecular pathways linking the 2-HMO formula feeding and LRTI mitigation. From the same trial, we measured the microbiota composition and 743 known biochemical species in infant stool at 3 months of age using shotgun metagenomic sequencing and untargeted mass spectrometry metabolomics. We used multivariate analysis to identify biochemicals associated to 2-HMO formula feeding and LRTI and integrated those findings with the microbiota compositional data. Three molecular pathways stood out: increased gamma-glutamylation and N-acetylation of amino acids and decreased inflammatory signaling lipids. Integration of stool metagenomic data revealed some Bifidobacterium and Bacteroides species to be implicated. These findings deepen our understanding of the infant gut/microbiome co-metabolism in early life and provide evidence for how such metabolic changes may influence immune competence at distant mucosal sites such as the airways.

Infant Formula With a Specific Blend of Five Human Milk Oligosaccharides Drives the Gut Microbiota Development and Improves Gut Maturation Markers: A Randomized Controlled Trial

Background

Human milk oligosaccharides (HMOs) have important biological functions for a healthy development in early life.

Objective

This study aimed to investigate gut maturation effects of an infant formula containing five HMOs (2′-fucosyllactose, 2′,3-di-fucosyllactose, lacto-N-tetraose, 3′-sialyllactose, and 6′-sialyllactose).

Methods

In a multicenter study, healthy infants (7–21 days old) were randomly assigned to a standard cow’s milk-based infant formula (control group, CG); the same formula with 1.5 g/L HMOs (test group 1, TG1); or with 2.5 g/L HMOs (test group 2, TG2). A human milk-fed group (HMG) was enrolled as a reference. Fecal samples collected at baseline (n∼150/formula group; HMG n = 60), age 3 (n∼140/formula group; HMG n = 65) and 6 (n∼115/formula group; HMG n = 60) months were analyzed for microbiome (shotgun metagenomics), metabolism, and biomarkers.

Results

At both post-baseline visits, weighted UniFrac analysis indicated different microbiota compositions in the two test groups (TGs) compared to CG (P < 0.01) with coordinates closer to that of HMG. The relative abundance of Bifidobacterium longum subsp. infantis (B. infantis) was higher in TGs vs. CG (P < 0.05; except at 6 months: TG2 vs. CG P = 0.083). Bifidobacterium abundance was higher by ∼45% in TGs vs. CG at 6-month approaching HMG. At both post-baseline visits, toxigenic Clostridioides difficile abundance was 75–85% lower in TGs vs. CG (P < 0.05) and comparable with HMG. Fecal pH was significantly lower in TGs vs. CG, and the overall organic acid profile was different in TGs vs. CG, approaching HMG. At 3 months, TGs (vs. CG) had higher secretory immunoglobulin A (sIgA) and lower alpha-1-antitrypsin (P < 0.05). At 6 months, sIgA in TG2 vs. CG remained higher (P < 0.05), and calprotectin was lower in TG1 (P < 0.05) vs. CG.

Conclusion

Infant formula with a specific blend of five HMOs supports the development of the intestinal immune system and gut barrier function and shifts the gut microbiome closer to that of breastfed infants with higher bifidobacteria, particularly B. infantis, and lower toxigenic Clostridioides difficile.

Clinical Trial Registration

[https://clinicaltrials.gov/ct2/show/], identifier [NCT03722550].

Effects of an Amino Acid-Based Formula Supplemented with Two Human Milk Oligosaccharides on Growth, Tolerability, Safety, and Gut Microbiome in Infants with Cow's Milk Protein Allergy

This open-label, non-randomized, multicenter trial (Registration: NCT03661736) aimed to assess if an amino acid-based formula (AAF) supplemented with two human milk oligosaccharides (HMO) supports normal growth and is well tolerated in infants with a cow's milk protein allergy (CMPA). Term infants aged 1-8 months with moderate-to-severe CMPA were enrolled. The study formula was an AAF supplemented with 2'-fucosyllactose (2'-FL) and lacto-N-neotetraose (LNnT). Infants were fed the study formula for 4 months and were offered to remain on the formula until 12 months of age. Tolerance and safety were assessed throughout the trial. Out of 32 infants (mean age 18.6 weeks; 20 (62.5%) male), 29 completed the trial. During the 4-month principal study period, the mean weight-for-age Z score (WAZ) increased from -0.31 at the baseline to +0.28 at the 4-months' follow-up. Linear and head growth also progressed along the WHO child growth reference, with a similar small upward trend. The formula was well tolerated and had an excellent safety profile. When comparing the microbiome at the baseline to the subsequent visits, there was a significant on-treatment enrichment in HMO-utilizing bifidobacteria, which was associated with a significant increase in fecal short-chain fatty acids. In addition, we observed a significant reduction in the abundance of fecal Proteobacteria, suggesting that the HMO-supplemented study formula partially corrected the gut microbial dysbiosis in infants with CMPA.

Four groups of type 2 diabetes contribute to the etiological and clinical heterogeneity in newly diagnosed individuals: An IMI DIRECT study

The presentation and underlying pathophysiology of type 2 diabetes (T2D) is complex and heterogeneous. Recent studies attempted to stratify T2D into distinct subgroups using data-driven approaches, but their clinical utility may be limited if categorical representations of complex phenotypes are suboptimal. We apply a soft-clustering (archetype) method to characterize newly diagnosed T2D based on 32 clinical variables. We assign quantitative clustering scores for individuals and investigate the associations with glycemic deterioration, genetic risk scores, circulating omics biomarkers, and phenotypic stability over 36 months. Four archetype profiles represent dysfunction patterns across combinations of T2D etiological processes and correlate with multiple circulating biomarkers. One archetype associated with obesity, insulin resistance, dyslipidemia, and impaired β cell glucose sensitivity corresponds with the fastest disease progression and highest demand for anti-diabetic treatment. We demonstrate that clinical heterogeneity in T2D can be mapped to heterogeneity in individual etiological processes, providing a potential route to personalized treatments.

Conjugated C-6 hydroxylated bile acids in serum relate to human metabolic health and gut Clostridia species

Knowledge about in vivo effects of human circulating C-6 hydroxylated bile acids (BAs), also called muricholic acids, is sparse. It is unsettled if the gut microbiome might contribute to their biosynthesis. Here, we measured a range of serum BAs and related them to markers of human metabolic health and the gut microbiome. We examined 283 non-obese and obese Danish adults from the MetaHit study. Fasting concentrations of serum BAs were quantified using ultra-performance liquid chromatography-tandem mass-spectrometry. The gut microbiome was characterized with shotgun metagenomic sequencing and genome-scale metabolic modeling. We find that tauro- and glycohyocholic acid correlated inversely with body mass index (P = 4.1e-03, P = 1.9e-05, respectively), waist circumference (P = 0.017, P = 1.1e-04, respectively), body fat percentage (P = 2.5e-03, P = 2.3e-06, respectively), insulin resistance (P = 0.051, P = 4.6e-4, respectively), fasting concentrations of triglycerides (P = 0.06, P = 9.2e-4, respectively) and leptin (P = 0.067, P = 9.2e-4). Tauro- and glycohyocholic acids, and tauro-a-muricholic acid were directly linked with a distinct gut microbial community primarily composed of Clostridia species (P = 0.037, P = 0.013, P = 0.027, respectively). We conclude that serum conjugated C-6-hydroxylated BAs associate with measures of human metabolic health and gut communities of Clostridia species. The findings merit preclinical interventions and human feasibility studies to explore the therapeutic potential of these BAs in obesity and type 2 diabetes.

Imidazole propionate is increased in diabetes and associated with dietary patterns and altered microbial ecology

Microbiota-host-diet interactions contribute to the development of metabolic diseases. Imidazole propionate is a novel microbially produced metabolite from histidine, which impairs glucose metabolism. Here, we show that subjects with prediabetes and diabetes in the MetaCardis cohort from three European countries have elevated serum imidazole propionate levels. Furthermore, imidazole propionate levels were increased in subjects with low bacterial gene richness and Bacteroides 2 enterotype, which have previously been associated with obesity. The Bacteroides 2 enterotype was also associated with increased abundance of the genes involved in imidazole propionate biosynthesis from dietary histidine. Since patients and controls did not differ in their histidine dietary intake, the elevated levels of imidazole propionate in type 2 diabetes likely reflects altered microbial metabolism of histidine, rather than histidine intake per se. Thus the microbiota may contribute to type 2 diabetes by generating imidazole propionate that can modulate host inflammation and metabolism.

Gut microbial metabolism of nutrients contributes to metabolic diseases, and the histidine metabolite imidazole propionate (ImP) is produced by type 2 diabetes (T2D) associated microbiome. Here the authors report that circulating ImP levels are increased in subjects with prediabetes or T2D in three European populations, and this increase associates with altered gut microbiota rather than dietary histidine.

Integrative network analysis highlights biological processes underlying GLP-1 stimulated insulin secretion: A DIRECT study

Glucagon-like peptide 1 (GLP-1) stimulated insulin secretion has a considerable heritable component as estimated from twin studies, yet few genetic variants influencing this phenotype have been identified. We performed the first genome-wide association study (GWAS) of GLP-1 stimulated insulin secretion in non-diabetic individuals from the Netherlands Twin register (n = 126). This GWAS was enhanced using a tissue-specific protein-protein interaction network approach. We identified a beta-cell protein-protein interaction module that was significantly enriched for low gene scores based on the GWAS P-values and found support at the network level in an independent cohort from Tübingen, Germany (n = 100). Additionally, a polygenic risk score based on SNPs prioritized from the network was associated (P < 0.05) with glucose-stimulated insulin secretion phenotypes in up to 5,318 individuals in MAGIC cohorts. The network contains both known and novel genes in the context of insulin secretion and is enriched for members of the focal adhesion, extracellular-matrix receptor interaction, actin cytoskeleton regulation, Rap1 and PI3K-Akt signaling pathways. Adipose tissue is, like the beta-cell, one of the target tissues of GLP-1 and we thus hypothesized that similar networks might be functional in both tissues. In order to verify peripheral effects of GLP-1 stimulation, we compared the transcriptome profiling of ob/ob mice treated with liraglutide, a clinically used GLP-1 receptor agonist, versus baseline controls. Some of the upstream regulators of differentially expressed genes in the white adipose tissue of ob/ob mice were also detected in the human beta-cell network of genes associated with GLP-1 stimulated insulin secretion. The findings provide biological insight into the mechanisms through which the effects of GLP-1 may be modulated and highlight a potential role of the beta-cell expressed genes RYR2, GDI2, KIAA0232, COL4A1 and COL4A2 in GLP-1 stimulated insulin secretion.

Pancreatic Islet Protein Complexes and Their Dysregulation in Type 2 Diabetes

Type 2 diabetes (T2D) is a complex disease that involves multiple genes. Numerous risk loci have already been associated with T2D, although many susceptibility genes remain to be identified given heritability estimates. Systems biology approaches hold potential for discovering novel T2D genes by considering their biological context, such as tissue-specific protein interaction partners. Pancreatic islets are a key T2D tissue and many of the known genetic risk variants lead to impaired islet function, hence a better understanding of the islet-specific dysregulation in the disease-state is essential to unveil the full potential of person-specific profiles. Here we identify 3,692 overlapping pancreatic islet protein complexes (containing 10,805 genes) by integrating islet gene and protein expression data with protein interactions. We found 24 of these complexes to be significantly enriched for genes associated with diabetic phenotypes through heterogeneous evidence sources, including genetic variation, methylation, and gene expression in islets. The analysis specifically revealed ten T2D candidate genes with probable roles in islets (ANPEP, HADH, FAM105A, PDLIM4, PDLIM5, MAP2K4, PPP2R5E, SNX13, GNAS, and FRS2), of which the last six are novel in the context of T2D and the data that went into the analysis. Fifteen of the twenty-four complexes were further enriched for combined genetic associations with glycemic traits, exemplifying how perturbation of protein complexes by multiple small effects can give rise to diabetic phenotypes. The complex nature of T2D ultimately prompts an understanding of the individual patients at the network biology level. We present the foundation for such work by exposing a subset of the global interactome that is dysregulated in T2D and consequently provides a good starting point when evaluating an individual's alterations at the genome, transcriptome, or proteome level in relation to T2D in clinical settings.

Ranking factors involved in diabetes remission after bariatric surgery using machine-learning integrating clinical and genomic biomarkers

As weight-loss surgery is an effective treatment for the glycaemic control of type 2 diabetes in obese patients, yet not all patients benefit, it is valuable to find predictive factors for this diabetic remission. This will help elucidating possible mechanistic insights and form the basis for prioritising obese patients with dysregulated diabetes for surgery where diabetes remission is of interest. In this study, we combine both clinical and genomic factors using heuristic methods, informed by prior biological knowledge in order to rank factors that would have a role in predicting diabetes remission, and indeed in identifying patients who may have low likelihood in responding to bariatric surgery for improved glycaemic control. Genetic variants from the Illumina CardioMetaboChip were prioritised through single-association tests and then seeded a larger selection from protein-protein interaction networks. Artificial neural networks allowing nonlinear correlations were trained to discriminate patients with and without surgery-induced diabetes remission, and the importance of each clinical and genetic parameter was evaluated. The approach highlighted insulin treatment, baseline HbA1c levels, use of insulin-sensitising agents and baseline serum insulin levels, as the most informative variables with a decent internal validation performance (74% accuracy, area under the curve (AUC) 0.81). Adding information for the eight top-ranked single nucleotide polymorphisms (SNPs) significantly boosted classification performance to 84% accuracy (AUC 0.92). The eight SNPs mapped to eight genes - ABCA1, ARHGEF12, CTNNBL1, GLI3, PROK2, RYBP, SMUG1 and STXBP5 - three of which are known to have a role in insulin secretion, insulin sensitivity or obesity, but have not been indicated for diabetes remission after bariatric surgery before.

Cardiovascular effects of MnDPDP and mncl2 in Dogs with Acute Ischaemic Heart Failured

Purpose: To examine the cardiovascular effects of MnDPDP in a model of acute heart failure in the dog, and to compare these effects with those of MnCl2.

Material and Methods: The study involved slow i.v. infusion of either 10,60 and 300 μmol/kg of MnDPDP, or 1, 6 and 30 μmol/kg MnCl2, in increasing doses to groups of 5 dogs. Acute ischaemic heart failure was first induced by injection of polystyrene microspheres (50 ± 10 μm) into the left coronary artery until a stable left ventricular end-diastolic pressure of approximately 20 mm Hg was achieved. The following test parameters were measured: left ventricular end-diastolic pressure; the first derivatives of maximum rate of left ventricular contraction and relaxation; mean aortic pressure; pulmonary artery pressure; right atrial pressure; cardiac ouput; heart rate; QT-time; PQ-time; QRS-width; and plasma catecholamines.

Results: Slow infusion of MnDPDP at doses up to and including 12 times the clinical dose was well tolerated in dogs without further depression of cardiovascular function during acute ischaemic heart failure. At 300 μmol/kg, i.e. 60 times the human dose, only minor haemodynamic and electrophysiological effects were seen, and these were similar to those seen after administration of 30 μmol/kg MnCl2.

Conclusion: The present study suggests that slow infusion of MnDPDP should not cause further deteroriation of cardiac function in patients with heart failure.

Pharmacogenomics in diabetes mellitus: insights into drug action and drug discovery

Genomic studies have greatly advanced our understanding of the multifactorial aetiology of type 2 diabetes mellitus (T2DM) as well as the multiple subtypes of monogenic diabetes mellitus. In this Review, we discuss the existing pharmacogenetic evidence in both monogenic diabetes mellitus and T2DM. We highlight mechanistic insights from the study of adverse effects and the efficacy of antidiabetic drugs. The identification of extreme sulfonylurea sensitivity in patients with diabetes mellitus owing to heterozygous mutations in HNF1A represents a clear example of how pharmacogenetics can direct patient care. However, pharmacogenomic studies of response to antidiabetic drugs in T2DM has yet to be translated into clinical practice, although some moderate genetic effects have now been described that merit follow-up in trials in which patients are selected according to genotype. We also discuss how future pharmacogenomic findings could provide insights into treatment response in diabetes mellitus that, in addition to other areas of human genetics, facilitates drug discovery and drug development for T2DM.

Hemispheric differences for visual matrix processing: stimulus size and spatial frequency effects

Hemispheric processing differences were assessed by presenting square matrices that varied in size and the number of filled-in cells. Subjects judged whether the matrix contained an even or odd number of filled cells. Experiment 1 employed relatively small matrix sizes (2 x 2, 3 x 3, and 4 x 4), and Experiment 2 employed relatively large matrix sizes (4 x 4, 6 x 6, and 8 x 8). Response time was shorter and error rates lower for left visual field/right hemisphere (LVF/RH) presentations compared to right visual field/left hemisphere (RVF/LH) presentations, with the larger matrices demonstrating the strongest visual field/hemispheric effects. Increases in the number of filled cells contributed to increases for the LVF/RH response time advantage only for the larger arrays. Analysis of the data from both studies collapsed across the number of filled cells produced highly consistent LVF/RH advantages for both response time and error rate, with stronger LVF/RH advantages found for the larger matrix sizes of both studies. The findings suggest that visual stimulus spatial frequency is a key determinant of hemispheric processing advantages, but that this factor is constrained by stimulus size variation. Theoretical implications with respect to the hemispheric processing double filtering by frequency model are discussed.

Improving postoperative MR imaging of pituitary macroadenomas: comparison of full and reduced dose of gadopentetate dimeglumine

The aim of this study was to evaluate the efficacy of contrast-medium (CM)-ehanced MR imaging of operated pituitary macroadenomas with reduced dose of gadopentetate dimeglumine. In a prospective study 18 patients were examined with coronal T1-weighted MR imaging prior to and following intravenous CM injections. Two sets of contrast-enhanced coronal images were obtained in each patient; the first set after 50% of the recommended dose of 0.1 mmol/kg body weight (b.w.) had been administered, and the second set immediately after additional CM had been given to make up a total dose of 0.1 mmol/kg b.w. The images were evaluated by three neuroradiologists. The SIPAP classification system was used to evaluate tumour extension, whereas tumour margin conspicuity was scored using an arbitrary scale of 1-5 (1 = indistinct, 5 = well defined). Signal intensity measurements obtained from the most enhancing part of the adenomas demonstrated increased enhancement with increased CM dose. Tumour delineation scores were significantly better on the reduced- and full-dose images than on pre-CM injection images, but, with one exception, tumour extension was identified as the same on all imaging sequences. Postoperative MR imaging of large macroadenoma residues can routinely be performed without intravenous CM. When CM is indicated a reduced dose of gadopentetate dimeglumine should provide sufficient diagnostic information.

CTA in patients with acute subarachnoid haemorrhage. A comparative study with selective, digital angiography and blinded, independent review

PURPOSE

Minimal- or non-invasive methods replacing intra-arterial digital subtraction angiography (IA-DSA) would be of great importance in patients suffering from acute subarachnoid haemorrhage (SAH). The aims of this study were to compare CTA with IA-DSA in patients with acute SAH, to compare CTA interpretations with those of blinded, independent reviewers and to evaluate improvement in CTA diagnostics after 1 year of experience with CTA.

MATERIAL AND METHOD

During 2 years 162 patients with SAH underwent CTA as well as IA-DSA. Independent blinded review of 77 patients was performed for 1 year.

RESULTS

Totally 144 aneurysms were demonstrated in 119 patients at IA-DSA, while 43 patients had normal intracranial arteries. Initially 131 aneurysms were detected at CTA while 2 normal, tortuous arteries were misinterpreted as aneurysms, giving a sensitivity of 91% and a specificity of 95%. At independent blinded review the observer agreement was 87% and the kappa value 0.68.

CONCLUSION

CTA in SAH is of great value in demonstrating vascular anatomy and the exact size of an aneurysm. However, IA-DSA is still needed for diagnostic evaluation in aneurysms smaller than 5 mm in diameter, especially in those located near bony structures.

Imaging routines for the esophagus, small bowel, abdomen, and liver in six Norwegian hospitals from 1975 to 1993

The roles of liver scintigraphy in addition to other imaging modalities of the esophagus and the small bowel and the use of abdominal flat films were studied in six Norwegian hospitals between 1975 and 1993. Parallel to the introduction of ultrasonography, the use of liver scintigraphy disappeared almost completely. Barium studies of the esophagus, to some degree, have been replaced by endoscopy, whereas use of barium studies of the small bowel remained unchanged or increased. The number of flat-film studies of the abdomen performed remained unchanged.

[Spread of an imported multiresistant Staphylococcus aureus to other hospitals via secondary colonized patients]

A secondary spread of an imported methicillin-resistant Staphylococcus aureus strain (MRSA) to two other patients occurred within a Danish surgical ward in spite of isolation of a multitraumatized index-patient immediately after arrival from a hospital in the Mediterranean area. The two other colonized patients were later transferred to other hospitals in Denmark where it became apparent that they had developed serious infections with the MRSA strain.

IN CONCLUSION

to prevent spread of imported MRSA within Danish hospitals, strict adherence to isolation procedures and a high level of general hygiene is essential not only when patients are transferred from hospitals situated in endemic areas of MRSA abroad, but also when admitted from Danish hospital wards where known cases of colonisation or infection with MRSA exist.

Coronary arteriography with an oxygenated contrast medium: cardiac effects in dogs with and without acute ischemic heart failure

RATIONALE AND OBJECTIVES

We investigated the possible cardiac effects of oxygen addition to contrast media (CM) during coronary arteriography in dogs that did and did not have ischemic heart failure.

METHODS

Acute ischemic heart failure was induced by injecting small plastic microspheres into the left coronary artery of 18 dogs. Hemodynamic and electrophysiologic measurements were performed during a single injection before and during heart failure and during a single injection and five rapidly repeated CM injections during heart failure. Iohexol supplemented with electrolytes (iohexol + electrolytes = IPE), oxygenated IPE (IPE+O), Ringer acetate, and oxygenated Ringer acetate were injected into the left coronary artery.

RESULTS

Single injections of IPE and IPE+O induced small hemodynamic and electrophysiologic effects. However, repeated injections of IPE and IPE+O increased left ventricular inotropy (maximum value of the first derivative of the left ventricular pressure) by 36% and 39%, reduced heart rate by 7% (for both), and lengthened QTc time (corrected QT interval) by 39 and 38 msec, respectively. A comparison of IPE and IPE+O revealed no statistically significant differences.

CONCLUSION

Although electrolyte addition to nonionic CM may reduce the risk of cardiac complications during coronary arteriography, oxygenation does not seem to significantly further reduce this risk.

Contrast-medium-induced ventricular fibrillation: arrhythmogenic mechanisms and the role of antiarrhythmic drugs in dogs

RATIONALE AND OBJECTIVES

Small electrolyte additions to a nonionic contrast medium reduce the risk of ventricular fibrillation (VF) during wedged catheter injection of a contrast medium. The current study was designed to further investigate contrast-medium-induced VF by studying the effect of pretreatment with different antiarrhythmic drugs.

METHODS

During a simulated wedged catheter situation, iohexol was injected into the anterior descending branch of the left coronary artery in five open-chest, anesthetized dogs pretreated with lidocaine, propranolol, amiodarone, almokalant, or verapamil.

RESULTS

Wedging the catheter for 60 sec did not induce VF. However, all 15 wedged catheter injections with iohexol induced VF within 28 sec (19 +/- 1 [mean +/- standard error of the mean]) despite pretreatment with antiarrhythmic drugs. Prior to VF, conduction was slowed and monophasic action potential duration lengthened in the contrast-medium-perfused myocardium, although no significant changes occurred in the control area.

CONCLUSION

The combination of catheter wedging and long-lasting contrast medium injection has a high risk of causing VF. Although adding a small amount of electrolytes to nonionic contrast media can reduce the risk of VF, antiarrhythmic drug therapy may not have a protective effect.

Additive hemodynamic and electrophysiologic effects of repeated intracoronary contrast media injections in dogs with heart failure

RATIONALE AND OBJECTIVES

We investigated the cardiac effects of single and repeated contrast media injections in dogs with heart failure and compared the effects of iohexol with iohexol supplemented with electrolytes (30 mmol/l NaCl, 0.15 mmol/l CaCl2, 0.9 mmol/l KCl, and 0.1 mmol/l MgCl2; iohexol + electrolytes [IPE]). Although it has a higher osmolality than iohexol, IPE appears to be safer when injected through a wedged catheter.

METHODS

Acute ischemic heart failure was induced by injections of small plastic microspheres into the left coronary artery of 16 anesthetized dogs. Iohexol, IPE, and Ringer acetate were injected into the left coronary artery either as a 5-ml single injection or repeatedly five times, once every 10th second.

RESULTS

Single injections of iohexol and IPE induced small hemodynamic and electrophysiologic effects. However, repeated injections of iohexol and IPE increased the maximum rate of isovolumetric contraction by 46% and 36%, reduced heart rate by 8% and 7%, and lengthened QTc (the Q-T interval corrected for heart rate) time by 44 and 39 msec, respectively. No statistically significant differences were found in a comparison of IPE and iohexol.

CONCLUSION

During heart failure, repeated injections of iohexol and IPE induced similar additive hemodynamic and electrophysiologic effects without inducing arrhythmias or serious hemodynamic changes.

Changes in radiological routines following the introduction of computed tomography. A retrospective study from two Norwegian hospitals

Diagnostic imaging routines have changed rapidly during the last two decades. The real revolution started with the introduction of computed tomography into routine clinical work in the middle of the 1970s. Simultaneously, a tremendous sophistication of ultrasonography took place, and shortly later, magnetic resonance imaging started its "career." The present report explores how the introduction of computed tomography changed imaging routines in two major Norwegian hospitals during the last 10 to 15 years.

Cardiac electrophysiology, arrhythmogenic mechanisms and roentgen contrast media

Contrast media (CM) affect normal cardiac electrophysiology when injected into the coronary arteries. High-osmolality CM cause more pronounced electrophysiological effects than do low-osmolality CM. Further, both high- and low-osmolality ionic CM have more pronounced effects than the nonionic CM. The CM-induced electrophysiological effects involve regional disturbances of depolarization and repolarization, thereby causing disturbances of impulse conduction as well as dispersion of refractoriness. Recent experimental studies have demonstrated that the addition of sodium or a balanced electrolyte supplement to nonionic CM reduces the risk of ventricular fibrillation (VF), particularly when the CM is injected in a wedged catheter situation. The reduced risk of VF may be due to the small and transient lengthening of repolarization seen in the CM-perfused area of the myocardium. Iodixanol, which is an isotonic nonionic dimer supplemented with NaCl and CaCl(2), is as well tolerated as iohexol during free coronary flow. However, when flow is restricted, such as when CM is injected through a wedged catheter, the risk of VF is less with iodixanol than with iopamidol, iohexol and ioxaglate.

Cardiac effects of adding electrolytes and oxygen to iohexol in a dog model of contrast media-induced ventricular fibrillation

We investigated whether addition of a balanced electrolyte supplement and oxygen to the nonionic contrast medium iohexol reduces the risk of ventricular fibrillation (VF), and studied regional electrophysiology prior to the VF event. Twenty ml of each test solution were infused at a rate of 0.5 ml/s into the left anterior descending coronary artery (LAD) in 8 anesthetized dogs. LAD was externally occluded during infusion, to simulate a wedged catheter situation. ECG, hemodynamics, regional epicardial monophasic action potential duration (MAPD) and ventricular activation times (VAT) were calculated. All infusions with iohexol caused VF within 27 s. Five of 12 infusions with iohexol + 30 mmol NaCl, 3 of 11 infusions with iohexol+electrolytes (IPE) NaCl, KCl, CaCl2 and MgCl2) and 4 of 11 infusions with IPE with oxygen addition (IPE+O2) caused VF after 45 s. Iohexol did not change MAPD prior to the VF event. Iohexol + 30 mmol NaCl and the IPE solutions lengthened MAPD initially, but at the time of the VF event MAPD were normalized or shortened. We conclude that electrolyte supplement to iohexol may prevent VF, probably by lengthening MAPD.

Changes in diagnostic imaging routines of the stomach and the large bowel during the period between 1975 and 1992

In a retrospective study on diagnostic imaging of the stomach and large bowel, we evaluated the examination routines in six Norwegian hospitals for the period between 1975 and 1992. For both organ systems, a shift in routines from radiological examination toward endoscopy was observed. For the stomach there was a significant correlation between an increase in the use of endoscopy and a decrease in the use of X-ray examinations. Additionally, the total number of stomach examinations had declined. For the large bowel, the total number of endoscopic and radiological examinations had increased for all hospitals studied. While not as prominent as for the stomach, an obvious shift from X-ray examinations toward endoscopy was observed. These results should be considered when planning new imaging departments and hospitals in Norway.

Contrast media-induced ventricular fibrillation: an experimental study of the effects of dimeric contrast media during wedged catheter injection in dogs

RATIONALE AND OBJECTIVES

We investigated the cardiac effects of an ionic dimer, ioxaglate and two nonionic dimers, iotrolan, and iodixanol.

METHODS

During a simulated wedged catheter situation, 22 ml of each contrast medium was injected into the left anterior descending branch of the left coronary artery in seven open-chested, anesthetized dogs.

RESULTS

Of 13 injections with each contrast medium, ioxaglate induced ventricular fibrillation in 11 after 34 +/- 5 sec, iotrolan in 6 after 42 +/- 4 sec, and iodixanol in 3 after 61 +/- 1 sec. Ioxaglate markedly lengthened monophasic action potential duration in contrast medium-perfused myocardium. Iotrolan, and iodixanol induced biphasic changes, first lengthening and then shortening action potential duration. The electrophysiological changes occurred later when using iodixanol.

CONCLUSIONS

The risk of ventricular fibrillation during long-lasting contrast media exposure to the myocardium, as in a wedged catheter situation, appears to be much lower with iodixanol compared with ioxaglate and also lower than when using iotrolan.

Cardiac effects of coronary arteriography with electrolyte addition to iohexol. A study in dogs with and without heart failure

Electrolyte addition to nonionic contrast media has been suggested to further reduce the incidence of ventricular fibrillation during coronary arteriography. The present study was designed to investigate the effects of adding 30 mM NaCl, 0.9 mM KCl, 0.15 mM CaCl2 and 0.1 mM MgCl2 to iohexol on cardiac electrophysiology and hemodynamics (iohexol+electrolytes = IPE). Contrast media were injected into the left main coronary artery in 9 open-chest, anesthetized dogs before and after induction of acute ischemic heart failure. IPE increased left ventricular inotropy (LV dP/dtmax) with no initial decrease, even during heart failure. During heart failure IPE induced the same hemodynamic effects as iohexol without electrolyte addition. IPE slightly lengthened epicardial monophasic action potential duration before heart failure. We conclude that IPE appears to be well tolerated hemodynamically. The electrophysiologic differences between IPE and iohexol are small when the injection time is not longer than 5 s.

Ultrasonography in medical imaging. Influence on diagnostic routines

It has been assumed that the introduction of ultrasonography in diagnostic imaging has led to dramatic changes in imaging routines by replacing other modalities like angiography, intravenous urography, and computerized tomography in several diagnostic procedures. The present retrospective study from five Norwegian hospitals during the period from 1978 to 1991 confirm this assumption, showing how ultrasonographic examinations have influenced diagnostic routines.

Repeated intracoronary injections of contrast media. Additive hemodynamic and electrophysiologic effects in a dog model

RATIONALE AND OBJECTIVES

Coronary arteriography in patients implies several selective injections into the coronary arteries. The authors investigate whether repeated injections cause additive cardiac hemodynamic and electrophysiologic effects in dogs.

METHODS

Five repeated injections of 5 mL iohexol (Omnipaque 350 mgI/mL, Nycomed Imaging AS, Oslo, Norway), ioxaglate (Hexabrix 320 mgI/mL, Laboratory Guerbet, Cedex, France), and sodium meglumine-diatrizoate (Renografin-76 370 mgI/mL, Squibb Diagnostics, Princeton, NJ) were given into the left coronary artery in 7 anesthetized dogs and were compared with the effects after a 5 mL single injection of the same medium. Left ventricular (LV) pressures, LV dP/dtmax (inotropy) and epicardial monophasic action potential were recorded, from which monophasic action potential duration (MAPD) was measured.

RESULTS

Repeated injections of ioxaglate and sodium meglumine-diatrizoate did not potentiate initial decrease in LV pressures and inotropy, but the secondary increase in LV inotropy increased more after repeated injections than after a single injection. Repeated injections of iohexol increased LV inotropy more than a single injection. All contrast media prolonged MAPD more after repeated injections than after single injections. MAPD was prolonged 30 sec after the last injection.

CONCLUSION

Repeated injections of contrast media cause greater cardiac hemodynamic and electrophysiologic effects than a single injection during selective coronary arteriography.

[Diagnostic imaging of the gastrointestinal and biliary tracts. Pattern of examinations during the period 1975-90]

The procedures used for imaging of the gastrointestinal tract, the gall bladder and the bile ducts were registered in six Norwegian hospitals during the period 1975-90. Data obtained from all hospitals showed a significant decrease in radiological examinations of the stomach and the large bowel, and a dramatic decrease of such examinations in the case of the gall bladder and bile ducts. The changes are mainly due to the increasing use of newer methods such as ultrasonography, gastroscopy and colonoscopy. The shift in the pattern of examinations, as shown in the present study, may well have many implications for patients and for the health service as a whole.

Restenosis after percutaneous transluminal coronary angioplasty

Restenosis after percutaneous transluminal coronary angioplasty was demonstrated in 61 (29%) of 210 successfully treated patients. Mostly it occurred within 4 months after treatment and in arteries less than 3 mm in diameter. Careful clinical follow-up is therefore particularly important early after angioplasty of smaller arteries. Redilation can be performed without increased risk of restenosis.

Radiological examinations of the urinary tract. Changes during the last 24 years

Procedures for imaging the urinary tract have been recorded in six Norwegian hospitals for the last 24 years. For three of the hospitals, data were collected from 1965 to 1989, and for the other three from 1966, 1971 and 1975, respectively. There was a significant reduction in the number of intravenous pyelograms, voiding cystograms, and renal angiograms, but the number of retrograde pyelograms and plain radiographs of the urinary tract remained constant. Computed tomography of the urinary tract increased during the first years, but after the introduction of ultrasonography, the number of computed tomograms decreased. Ultrasonographic examinations of the urinary tract are still rapidly increasing, and seem to have replaced some of the other imaging techniques. The present results should be taken into consideration when planning the health care for the future.

[Restenosis after coronary angioplasty]

Angiography of 169 patients who had been treated successfully with PTCA showed restenosis in 61. Of these, 38 were successfully treated with a new PTCA, and six developed a new restenosis. Restenosis usually appears during the first four months after PTCA in vessels with a diameter less than three millimeters. The authors emphasize the importance of careful clinical follow-up.

Percutaneous transluminal coronary angioplasty. Six years experience

In a six-year period (1982-1987), 248 patients were treated with 297 procedures (percutaneous transluminal coronary angioplasty, PTCA) on 282 vessels. Two hundred and fifty-nine (87.2%) of the procedures in 210 (76.7%) of the patients appeared successful angiographically. Thirty-eight procedures were unsuccessful due to failure to pass the stenosis in 18 patients, dissection or occlusion of the treated vessel in 11, and significant residual stenosis in 9 patients. Emergency operations were performed after 11 (3.7%) of the procedures. Two patients died postoperatively. Myocardial infarction was seen in 13 patients, of whom 4 developed pathologic Q-waves in their ECG. Restenosis occurred in 60 (28.6%) of the patients. In the last year of the study, the patients selected for PTCA were in a poorer state angiographically, but the results of PTCA were better, without any increase of the complication rate. Our results, which are in accordance with others, support the concept that PTCA is a relatively safe procedure with a primary success rate of almost 90 percent. However, approximately one third of the patients developed restenosis, which in most cases occurred within 3 months.

Renal angiography may be used primarily in the diagnosis of renovascular hypertension

Three hundred and twenty consecutive patients with hypertension were referred to examination with intravenous urography. Only 2 of the 320 urograms performed showed abnormalities possibly related to hypertension. Renal angiography was performed in 39 (12%) of the patients. Seventeen (7%) subjects had renal artery stenosis, of whom 8 (2.5%) were referred to surgery. Four became normotensive and the other 4 had a more treatable hypertension. Urography is an expensive and insensitive method for evaluation of patients with hypertension and should be abandoned. Proper treatment of renovascular hypertension demands the performance of renal angiography. We therefore suggest a program for primary use of renal angiography in the examination of patients with suspected renovascular hypertension.

Intravenous urography in children and youth

This report derives from Tromsoe in northern Norway. In a retrospective study of the indications for intravenous urography (IU) and the findings at IU in 740 patients (451 girls and 289 boys) aged 0-19 years, we found that urinary tract infections accounted for 69.4% of the IU in females 30.1% of the IU in males, most often seen in the youngest patients. The pathological findings most frequently seen were anomalies (17 females and 10 males) and urinary tract obstruction (3 females and 15 males). The present study indicates the following: first, that the yield of IU in the primary investigation of children and youth suffering from enuresis and non-specific abdominal disturbancies is small; and second, that the use of IU in children and youth with urinary tract infection and haematuria should be questioned and reconsidered.

Intravenous urography and voiding cystoureterography in northern Norway: a retrospective study

Intravenous urography (IU) was performed in 489 patients aged 0-9 years during 1980-1983. A total of 35 (7.2%), 19 (13.1%) boys and 16 (4.7%) girls had pathological changes at IU. Of these, 11 boys and 5 girls had findings with therapeutic consequences. We have analysed the results of IU and voiding cystoureterography (VC) in 62 patients and show that a normal IU does not exclude vesicoureteral reflux into the renal pelvis. By performing only VC hydronephrosis, pyelonephritic scarring and anomalies may be missed.