A pragmatic diagnostic approach to myocardial infarction with non-obstructive coronary arteries.

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is an increasingly recognised condition and it accounts for approximately 10% of all cases of MI. Despite the absence of obstructive coronary artery disease, patients with MINOCA are at increased risk of morbidity and mortality compared to the general population. While many well recognised conditions can present as MINOCA, it can be difficult to reach a final diagnosis with certainty due to the relative infrequency of these conditions in the general population and the lack of diagnostic gold-standard tests. The most common causes of MINOCA are myocarditis, coronary vasospasm, coronary plaque disruption and coronary thrombus or embolism. These can be assessed by way of cardiac magnetic resonance imaging, intra-coronary imaging modalities and clinically relevant diagnostic blood tests, respectively. There are less common and rarer aetiologies which should be considered in the absence of an apparent cause, each with a unique diagnostic standard. By following a systematic approach of diagnostic tests, an underlying cause of MINOCA can be found in the majority of cases, allowing a directed management strategy to be pursued.

Nature and delivery of cardiac rehabilitation in New Zealand: are services equitable to other high-income countries?

AIMS: To compare the nature and delivery of cardiac rehabilitation (CR) services within New Zealand by island (North vs South; NI, SI), and to other high-income countries (HICs). METHODS: In this cross-sectional study, secondary analysis of an online survey of CR programmes globally was undertaken. Results from New Zealand were compared to data from other HICs with CR. RESULTS: Twenty-seven (62.7%) out of 43 CR programmes in New Zealand (n=18/31, 66.7% respondents from NI) and 619 (43.1%) from 28 other HICs completed the survey. New Zealand CR programmes offered a median of 16.0 sessions/patient (interquartile range (IQR)=12.0-36.0; vs 21.6 sessions in other HICs, IQR=12.0-36.0, p=0.016), delivered by a team of 6.0 staff (IQR=5.5-7.0; vs 7.0 staff; IQR=5.0-9.0, p=0.012). New Zealand programmes were significantly less comprehensive than other HICs (p=0.002); within New Zealand, NI programmes were more likely to provide an initial and end-of-programme assessment, supervised exercise training and depression screening, compared to SI programmes (all p<0.05). New Zealand more often offered CR in an alternative setting (n=14, 58.3%), compared to other HICs (n=190, 36.5%), p=0.03). CONCLUSIONS: CR programmes in New Zealand offer fewer sessions and have fewer elements compared to other HICs, and disparity exists in programmes across New Zealand. More investment is needed to ensure CR in New Zealand meets international guidelines.

Cardiometabolic risk factors in vegans; A meta-analysis of observational studies.

BACKGROUND: There is increasing evidence that plant based diets are associated with lower cardiovascular risk. OBJECTIVE: To evaluate effects of a vegan compared to an omnivorous diet on cardio-metabolic risk factors. METHODS: Meta-analysis of observational studies published between 1960 and June 2018 that reported one or more cardio-metabolic risk factors in vegans and controls eating an omnivorous diet were undertaken. Macro-nutrient intake and cardio-metabolic risk factors were compared by dietary pattern. The Newcastle Ottawa Scale (NOS) was used to assess the quality of each study. The inverse-variance method was used to pool mean differences. Statistical analyses were performed using RevMan software version 5•2 (The Nordic Cochrane Centre, The Cochrane Collaboration, Copenhagen. RESULTS: 40 studies with 12 619 vegans and 179 630 omnivores were included. From food frequency questionnaires in 28 studies, vegans compared to omnivores consumed less energy (-11%, 95% confidence interval -14 to -8) and less saturated fat (- 51%, CI -57 to -45). Compared to controls vegans had a lower body mass index (-1.72 kg/m2, CI -2.30 to -1.16), waist circumference (-2.35 cm, CI -3.93 to -0.76), low density lipoprotein cholesterol (-0.49 mmol/L CI -0.62 to -0.36), triglycerides (-0.14 mmol/L, CI -0.24 to -0.05), fasting blood glucose (-0.23 mmol/, CI -0.35 to -0.10), and systolic (-2.56 mmHg, CI -4.66 to -0.45) and diastolic blood pressure (-1.33 mmHg, CI -2.67 to -0.02), p<0.0001 for all. Results were consistent for studies with < and ≥ 50 vegans, and published before and after 2010. However in several large studies from Taiwan a vegan diet was not associated with favourable cardio-metabolic risk factors compared to the control diets. CONCLUSION: In most countries a vegan diet is associated with a more favourable cardio- metabolic profile compared to an omnivorous diet.

The effects of changing dairy intake on trans and saturated fatty acid levels- results from a randomized controlled study.

BACKGROUND: Dairy food is an important natural source of saturated and trans fatty acids in the human diet. This study evaluates the effect of dietary advice to change dairy food intake on plasma fatty acid levels known to be present in milk in healthy volunteers. METHODS: Twenty one samples of whole fat dairy milk were analyzed for fatty acids levels. Changes in levels of plasma phospholipid levels were evaluated in 180 healthy volunteers randomized to increase, not change or reduce dairy intake for one month. Fatty acids were measured by gas chromatography-mass spectrometry and levels are normalized to d-4 alanine. RESULTS: The long chain fatty acids palmitic (13.4%), stearic (16.7%) and myristic (18.9%) acid were most common saturated fats in milk. Four trans fatty acids constituted 3.7% of the total milk fat content. Increased dairy food intake by 3.0 (± 1.2) serves/ day for 1 month was associated with small increases in plasma levels of myristic (+0.05, 95% confidence level-0.08 to 0.13, p = 0.07), pentadecanoic (+0.014, 95% confidence level -0.016 to 0.048, p = 0.02) and margaric acid (+0.02, -0.03 to 0.05, p = 0.03). There was no significant change in plasma levels of 4 saturated, 4 trans and 10 unsaturated fatty acids. Decreasing dairy food intake by 2.5 (± 1.2) serves per day was not associated with change in levels of any plasma fatty acid levels. CONCLUSION: Dietary advice to change dairy food has a minor effect on plasma fatty acid levels. TRIAL REGISTRATION: ACTRN12612000574842.

A randomized trial evaluating the effects of change in dairy food consumption on cardio-metabolic risk factors.

BACKGROUND: It is currently not known whether dairy food influences the risk of cardiovascular disease or diabetes. This study evaluates effects of changing dairy intake on cardio-metabolic risk factors. METHODS: 180 healthy volunteers were randomised to increase, reduce or not change their dairy intake for 1 month in response to dietary advice. Body weight, waist circumference, blood pressure, fasting plasma lipids, insulin resistance and C-reactive protein (CRP) were measured at baseline and after 1 month and compared by dietary group. RESULTS: 176 (98%) subjects completed the study. Average change in self-reported dairy fat intake for increased dairy food was +0.9 SD 1.1 g/day (+71%), no change was -2.1 SD 0.4 g/day (-15%) and decreased dairy food was -10.8 SD 1.2 g/day (-77%) respectively. There was no statistically significant change in LDL or HDL cholesterol, triglycerides, systolic or diastolic blood pressure, C-reactive protein, glucose or insulin with 95% CI standard mean differences <0.2 for all and CRP <0.3. There was a small increase in weight (+0.4 kg, SD 3.1) in those asked to increase dairy food. CONCLUSIONS: In healthy volunteers, dietary advice to change dairy intake for 1 month did not have a clinically significant effect on cardio-metabolic risk factors. These observations suggest that dairy food can be included as part of a normal healthy diet without increasing cardio-metabolic risk. TRIAL REGISTRATION NUMBER: ACTRN12612000574842.

Effects of high and low fat dairy food on cardio-metabolic risk factors: a meta-analysis of randomized studies.

IMPORTANCE: Clear guidelines on the health effects of dairy food are important given the high prevalence of obesity, cardiovascular disease and diabetes, and increasing global consumption of dairy food. OBJECTIVE: To evaluate the effects of increased dairy food on cardio metabolic risk factors. DATA SOURCES: Searches were performed until April 2013 using MEDLINE, Science Direct, Google,Embase, the Cochrane Central Register of Controlled Trials, reference lists of articles, and proceedings of major meetings. STUDY SELECTION: Randomized controlled studies with healthy adults randomized to increased dairy food for more than one month without additional interventions. DATA EXTRACTION AND SYNTHESIS: A standard list was used to extract descriptive, methodological and key variables from all eligible studies. If data was not included in the published report corresponding authors were contacted. RESULTS: 20 studies with 1677 participants with a median duration of dietary change of 26 (IQR 10-39) weeks and mean increase in dairy food intake of 3.6 (SD 0.92) serves/day were included. Increased dairy food intake was associated with a modest weight gain (+0.59, 95% confidence interval 0.34 to 0.84kg, p<0.0001) but no significant change in waist circumference (0.35 , -0.75 to 1.45 cm); insulin resistance (HOMA ­IR -0.94 , -1.93 to 0.05 units); fasting glucose (0.87, -0.27 to 2.01 mg/dl); LDL-cholesterol (1.36 ,-2.38 to 5.09 mg/dl); HDL-cholesterol (0.45, -2.13 to 3.04 mg/dl); systolic (-0.13, -1.73 to 1.98 mmHg) and diastolic blood pressure (0.13, -1.73 to 1.98 mmHg) or C-reactive protein (-0.08, -0.63 to 0.48 mg/L). Results were similar for studies with low-fat and whole-fat dairy interventions. LIMITATIONS: Most clinical trials were small and of modest quality. . CONCLUSION: Increasing whole fat and low fat dairy food consumption increases weight but has minor effects on other cardio-metabolic risk factors. TRIAL REGISTRATION ACTRN: Australian New Zealand Clinical Trials Registry ACTRN12613000401752, http://www.anzctr.org.au. ETHICS APPROVAL NUMBER: NTX/10/11/115.

Improving the informed consent process--a booklet on participants' rights in medical research.

AIM: This paper describes the process undertaken to develop and validate a booklet that informs participants of their rights in clinical studies. A booklet coupled with a shorter study-specific informed consent form may improve informed consent. METHODS: A booklet was developed in simple clear language, based on information contained in currently used audited informed consent forms and good clinical practice guidelines. 159 people from a broad range of backgrounds with expertise or interest in the consent process were asked to review the booklet and complete a survey. The booklet was modified based on feedback received from 59 respondents. RESULTS: Feedback was used to improve the booklet and ensure it complied with guidelines, was legally accurate and sensitive to tanga te whenua (Maori/indigenous people). The booklet was easier to read and comprehend compared to equivalent information contained in currently used informed consent forms. CONCLUSIONS: A broad consultation and revisions improved the booklet and suggested it would be well received if introduced in New Zealand together with shorter study-specific informed consent forms.

A booklet on participants' rights to improve consent for clinical research: a randomized trial.

OBJECTIVE: Information on the rights of subjects in clinical trials has become increasingly complex and difficult to understand. This study evaluates whether a simple booklet which is relevant to all research studies improves the understanding of rights needed for subjects to provide informed consent. METHODS: 21 currently used informed consent forms (ICF) from international clinical trials were separated into information related to the specific research study, and general information on participants' rights. A booklet designed to provide information on participants' rights which used simple language was developed to replace this information in current ICF's Readability of each component of ICF's and the booklet was then assessed using the Flesch-Kincaid Reading ease score (FK). To further evaluate the booklet 282 hospital inpatients were randomised to one of three ways to present research information; a standard ICF, the booklet combined with a short ICF, or the booklet combined with a simplified ICF. Comprehension of information related to the research proposal and to participant's rights was assessed by questionnaire. RESULTS: Information related to participants' rights contributed an average of 44% of the words in standard ICFs, and was harder to read than information describing the clinical trial (FK 25 versus (vs.) 41 respectively, p = 0.0003). The booklet reduced the number of words and improved FK from 25 to 42. The simplified ICF had a slightly higher FK score than the standard ICF (50 vs. 42). Comprehension assessed in inpatients was better for the booklet and short ICF 62%, (95% confidence interval (CI) 56 to 67) correct, or simplified ICF 62% (CI 58 to 68) correct compared to 52%, (CI 47 to 57) correct for the standard ICF, p = 0.009. This was due to better understanding of questions on rights (62% vs. 49% correct, p = 0.0008). Comprehension of study related information was similar for the simplified and standard ICF (60% vs. 64% correct, p = 0.68). CONCLUSIONS: A booklet provides a simple consistent approach to providing information on participant rights which is relevant to all research studies, and improves comprehension of patients who typically participate in clinical trials.

Trans-fatty acids in New Zealand patients with coronary artery disease.

BACKGROUND: Dietary surveys indicate that New Zealanders have a low intake of trans-fatty acids (TFA) with little derived from industrial sources. This observational cross-sectional study in New Zealand patients with surgical coronary artery disease assesses the plasma levels of TFA and the association of TFA levels with clinical markers of vascular disease. METHODS: 390 patients with severe coronary artery had fasting blood tests taken. Plasma levels of four TFA derived from hydrogenated vegetable oils and ruminant animal products were measured by gas chromatography. Relations between plasma TFA levels and the recent occurrence of myocardial infarction, the presence of polyvascular disease, and serum levels of C-reactive protein (CRP) were assessed. RESULTS: The median TFA level was 0.85% by weight of total fatty acids (IQR 0.59-1.79%), with skewed distribution to the right. For the lowest (<0.74%), middle (0.74-1.07%), and highest (>1.07%) thirds of total TFA, respectively, the proportion of patients with polyvascular disease was 10%, 16%, and 27% (p = 0.0004). Plasma CRP also increased by tertile of TFA (median 2.0, 2.9, 3.2 mg/l, p = 0.007). The association with polyvascular diseases and CRP remained significant after adjustment for risk factors. Significant associations were present between plasma TFA from both ruminant and hydrogenated vegetable oil sources and these markers of cardiovascular risk. CONCLUSIONS: There is an association between relatively low plasma levels of total TFA, mostly derived from ruminant sources, and an increased risk of polyvascular disease and increased CRP in patients with severe coronary artery disease. These high-risk patients may benefit from a targeted approach to minimize all sources of TFA in the diet.

Is it time to stop treating dyslipidaemia with fibrates?

AIM: To determine whether evidence from randomised clinical trials supports the use of fibrates to reduce non-fatal and fatal cardiovascular events in patients with dyslipidaemia. METHOD: Review of randomised clinical trials of fibrates that assess clinical outcomes. RESULT: In clinical trials which have which have included over 40,000 patients there was no difference in all cause mortality for patients randomised to a fibrate compared to placebo. Treatment with a fibrate was associated with a small reduction in the risk of non-fatal cardiovascular events. DISCUSSION: Current evidence does not support the use of fibrates to reduce cardiovascular mortality. Other proven strategies including statins, aspirin, angiotension converting enzyme (ACE) inhibitors, good blood pressure control, and lifestyle interventions should be used to reduce cardiovascular risk.

Trans fats in New Zealand: time for labelling regulations?

Trans fats (trans fatty acids) are commonly used for deep frying in restaurants and in the fast food, snack food, fried food, and baked goods industries, often to extend the shelf life of foods. However they are widely considered to be harmful to health. Trans fats were banned in New York City restaurants from 1 July 2007, and there is growing vocal opposition to trans fats in the European Union. Denmark became the first country, in March 2003, to introduce laws regulating the content of trans fats in food (maximum of 2% of edible fats and oils). What are trans fats, what harm do they cause, and should New Zealand also consider imposing mandatory regulations on their use in food? This article explores the issues.