2024 Australia-New Zealand Expert Consensus Statement on Cardiac Amyloidosis

Over the past 5 years, early diagnosis of and new treatments for cardiac amyloidosis (CA) have emerged that hold promise for early intervention. These include non-invasive diagnostic tests and disease modifying therapies. Recently, CA has been one of the first types of cardiomyopathy to be treated with gene editing techniques. Although these therapies are not yet widely available to patients in Australia and New Zealand, this may change in the near future. Given the rapid pace with which this field is evolving, it is important to view these advances within the Australian and New Zealand context. This Consensus Statement aims to update the Australian and New Zealand general physician and cardiologist with regards to the diagnosis, investigations, and management of CA.

Euglycemic Ketoacidosis in Two Patients Without Diabetes After Introduction of Sodium-Glucose Cotransporter 2 Inhibitor for Heart Failure With Reduced Ejection Fraction

OBJECTIVE

Ketoacidosis induced by sodium-glucose cotransporter 2 inhibitor (SGLT2i) treatment has been consistently observed in clinical practice in patients with type 2 diabetes despite minimal indication from the landmark cardiovascular outcome trials. It has been postulated that individuals without diabetes will not develop this complication due to an adequate insulin secretory capacity, which will protect against significant ketone formation. Cardiovascular outcome trials examining SGLT2i use in individuals with heart failure but not diabetes have not reported ketoacidosis.

RESEARCH DESIGN AND METHODS

We describe the first two case reports of severe nondiabetic ketoacidosis after initiation of an SGLT2i for the treatment of heart failure with reduced ejection fraction, and we describe the management strategies employed and implication for the pathophysiology of SGLT2i-associated ketoacidosis.

RESULTS

Each individual presented with ketoacidosis triggered by reduced oral nutrition intake. For both individuals, ketoacidosis resolved with intravenous glucose administration, encouragement of consumption of oral glucose-containing fluid, and minimal insulin administration.

CONCLUSIONS

These two cases demonstrate that SGLT2i-associated ketoacidosis is possible in individuals without diabetes.

Impact of Late Gadolinium Enhancement on mortality, sudden death and major adverse cardiovascular events in ischemic and nonischemic cardiomyopathy: A systematic review and meta-analysis

BACKGROUND

The central role of left ventricular ejection fraction (LVEF) as the definitive risk marker of adverse outcomes in ischemic and nonischemic cardiomyopathy is increasingly uncertain. The current study aimed to conduct a systematic review and meta-analysis with the objective of evaluating the prognostic importance of Late Gadolinium Enhancement (LGE) in ischemic cardiomyopathy (ICM) and non-ischemic cardiomyopathy (NICM) on the key endpoints of all-cause mortality, cardiovascular mortality and sudden death.

METHODS

The study was prospectively registered in PROPSERO (CRD 42016039034). Electronic databases and reference lists were searched for studies evaluating the impact of LGE-CMR on all-cause mortality, cardiovascular mortality, ventricular arrhythmia or sudden death, or major adverse cardiovascular events. Data were extracted from 36 studies including n=7882 patients.

RESULTS

LGE was strongly associated with all-cause mortality HR 2.96 (95%CI: 2.37, 3.70, P<0.001), cardiovascular mortality HR 3.27 (95% CI: 2.05, 5.22, P<0.001), ventricular arrhythmia and sudden cardiac death HR 3.76 (95% CI: 3.14, 4.52, P<0.001), and major adverse cardiovascular events HR 3.24 (95% CI: 2.32, 4.52, P<0.001). In subgroup analyses, LGE was associated with all-cause mortality and cardiovascular mortality in both LVEF≤35% and LVEF>35% patients (P<0.001 all endpoints), as well as in nonischemic and ischemic cardiomyopathy.

CONCLUSION

Late Gadolinium Enhancement (LGE) in CMR predicts all-cause mortality, cardiovascular mortality, ventricular arrhythmia and sudden death, and major adverse cardiovascular events, independent of LVEF. Future trials of investigational therapies in NICM and ICM should consider the utilization of LGE to identify patients at risk of adverse outcomes.

The relationship among homocysteine, creatinine clearance, and albuminuria in patients with type 2 diabetes

OBJECTIVE

Although it is accepted that elevated plasma homocysteine (tHcy) levels occur in end-stage renal disease and type 2 diabetes, the changes with milder renal dysfunction (e.g., microalbuminuria) are less clearly established. This study explores the relationship among tHcy, creatinine clearance (Ccr), and albumin excretion rate (AER) in a population with type 2 diabetes.

RESEARCH DESIGN AND METHODS

A total of 260 patients with type 2 diabetes were screened in our outpatient clinic during 10 months. Fasting blood samples were collected, and AER was calculated from an overnight timed urine sample. Ccr was calculated using the Cockroft-Gault formula.

RESULTS

A total of 198 subjects (76%) had normoalbuminuria (<20 microg/min), 50 subjects (19%) had microalbuminuria (20-200 microg/min), and 12 subjects (5%) had macroalbuminuria (>or=200 microg/min). Those with microalbuminuria had higher levels of tHcy than those with normoalbuminuria (13.2 +/- 7.8 vs. 11.3 +/- 4.6 micromol/l, P < 0.05). Patients were then subdivided based on low Ccr (<80 ml x min(-1) x 1.73 m(-2)) and normal Ccr (>or=80 x min(-1) x 1.73 m(-2)). None of the patients with macroalbuminuria had normal Ccr. In those with normoalbuminuria, tHcy levels were higher than in those with low Ccr than in those with normal Ccr (12.0 +/- 4.6 vs. 10.0 +/- 4.4 micromol/l, P < 0.01). The same was found for those with microalbuminuria (low Ccr versus normal Ccr: 14.6 +/- 9.0 vs. 10.2 +/- 2.8 micromol/l, P < 0.02). For normal Ccr, tHcy was similar irrespective of AER (normoalbuminuria versus microalbuminuria: 10.0 +/- 4.4 vs. 10.2 +/- 2.8 micromol/l, NS). For low Ccr, tHcy was higher in those with microalbuminuria versus normoalbuminuria (14.6 +/- 9.0 vs. 12.0 +/- 4.6 micromol/l, P = 0.01). Using multivariate regression, Ccr, but neither AER nor the presence of albuminuria, was an independent predictor of tHcy.

CONCLUSIONS

These data strongly suggest that in patients with type 2 diabetes, the relationship between plasma tHcy and AER is largely due to associated changes in renal function, as defined by Ccr.

Identification of Mycobacterium species by multiple-fluorescence PCR-single-strand conformation polymorphism analysis of the 16S rRNA gene

Identification of mycobacteria to the species level by growth-based methodologies is a process that has been fraught with difficulties due to the long generation times of mycobacteria. There is an increasing incidence of unusual nontuberculous mycobacterial infections, especially in patients with concomitant immunocompromised states, which has led to the discovery of new mycobacterial species and the recognition of the pathogenicity of organisms that were once considered nonpathogens. Therefore, there is a need for rapid and sensitive techniques that can accurately identify all mycobacterial species. Multiple-fluorescence-based PCR and subsequent single-strand conformation polymorphism (SSCP) analysis (MF-PCR-SSCP) of four variable regions of the 16S rRNA gene were used to identify species-specific patterns for 30 of the most common mycobacterial human pathogens and environmental isolates. The species-specific SSCP patterns generated were then entered into a database by using BioNumerics, version 1.5, software with a pattern-recognition capability, among its multiple uses. Patient specimens previously identified by 16S rRNA gene sequencing were subsequently tested by this method and were identified by comparing their patterns with those in the reference database. Fourteen species whose SSCP patterns were included in the database were correctly identified. Five other test organisms were correctly identified as unique species or were identified by their closest relative, as they were not in the database. We propose that MF-PCR-SSCP offers a rapid, specific, and relatively inexpensive identification tool for the differentiation of mycobacterial species.

Heat-labile proteases in molecular biology applications

Thermolabile proteases were identified in three Gram-negative psychrotrophic bacteria. The protease from the psychrotrophic strain A9 was purified and its application to common molecular biology techniques was demonstrated. Heat-stable molecular biology enzymes (Taq polymerase and PvuII) were digested by a heat-labile protease, which was then inactivated by a mild heat treatment. The clear benefit of using heat-labile proteases arises in situations where further reactions may be accomplished without an intermediate purification step, thereby saving time and avoiding the possibility of product loss.

Evaluation of recA sequences for identification of Mycobacterium species

16S rRNA sequence data have been used to provide a molecular basis for an accurate system for identification of members of the genus Mycobacterium. Previous studies have shown that Mycobacterium species demonstrate high levels (>94%) of 16S rRNA sequence similarity and that this method cannot differentiate between all species, i.e., M. gastri and M. kansasii. In the present study, we have used the recA gene as an alternative sequencing target in order to complement 16S rRNA sequence-based genetic identification. The recA genes of 30 Mycobacterium species were amplified by PCR, sequenced, and compared with the published recA sequences of M. tuberculosis, M. smegmatis, and M. leprae available from GenBank. By recA sequencing the species showed a lower degree of interspecies similarity than they did by 16S rRNA gene sequence analysis, ranging from 96.2% between M. gastri and M. kansasii to 75.7% between M. aurum and M. leprae. Exceptions to this were members of the M. tuberculosis complex, which were identical. Two strains of each of 27 species were tested, and the intraspecies similarity ranged from 98.7 to 100%. In addition, we identified new Mycobacterium species that contain a protein intron in their recA genes, similar to M. tuberculosis and M. leprae. We propose that recA gene sequencing offers a complementary method to 16S rRNA gene sequencing for the accurate identification of the Mycobacterium species.

The sustainability indicator industry:where to from here? A focus group study to explore the potential of farmer participation in the development of indicators

In Australia, the work being carried out on sustainability indicators has become an industry on its own. This paper firstly provides an introduction that reviews the literature on indicator development and use, particularly in relation to agricultural production systems. A number of reasons for the limited use of indicators by farmers are mentioned. Secondly, a focus group study involving farmers from two dryland cropping areas in Queensland to investigate sustainability indicators and sustainable farming systems is presented. The indicators the participants identified during focus groups included indicators that reflect (i)farming system components, (ii) the management of these components, (iii) the management of all components and their interrelationships at the systems level, and (iv) the external factors that influence and interact with this systems level. Focus group analysis also showed that the participants perceived sustainability as an on-going process and a sustainable farming system as dynamic and emergent in nature. The implications of these findings are discussed. Three key issues were raised (i) the value of farmer knowledge with respect to the development of indicators has often been ignored; (ii) there are links between indicators developed through traditional science and those being used by farmers; and (iii) off-farm indicators used by farmers may be very useful in policy development at a variety of levels (e.g. catchment, regional, national, global). The focus group method involving farmers provided a useful way to gain insights about farmer perceptions and for farmers to learn from each other during the research process.

Effect of cultivar on uptake of cadmium by potato tubers

Cadmium (Cd) accumulation in tubers by commercial potato cultivars was assessed at 12 sites around Australia having differing soil and environmental conditions. At all but two sites there were significant differences in tuber Cd concentrations between cultivars. Some major commercial cultivars had tuber Cd concentrations only half that of others. Advanced breeding lines showed further potential to reduce Cd accumulation. Mean tuber Cd concentrations of the 14 most common cultivars, averaged across all sites, ranged from 30 to 50 8g kg-1 fresh weight (FW), below the maximum permitted concentration (MPC) of 50 8g kg-1 of Cd (FW). However, at some sites certain cultivars exceeded the MPC. A modified joint regression analysis of the data indicated that no cultivars have consistently low or consistently high tuber Cd concentrations across a range of environments. While differences between cultivars were significant, the range in Cd concentrations found between sites was generally greater than the range in Cd concentrations between cultivars at any one site. Thus soil and other site factors (e.g. irrigation water quality, climate, etc.) play a dominant role in controlling Cd accumulation by current commercial cultivars and there is a need to breed new cultivars resistant to Cd accumulation under a wide range of environments.