Pharmacologic therapy among patients with type 2 diabetes mellitus admitted to the cardiology service

AIM

To review the management of diabetes control in patients with type 2 diabetes admitted to the cardiology service at Auckland City Hospital for over 48 hours; to assess how many would potentially benefit from introduction of empagliflozin under current Pharmac guidelines.

METHODS

A retrospective audit of all admissions into cardiology between 1 November 2020 and 31 January 2021 prior to the availability of empagliflozin. Data collected included diagnosis and presence of type 2 diabetes, HbA1c and diabetes medications.

RESULTS

A total of 449 patients were admitted, of whom 98 had type 2 diabetes. The median age was 64 years old (IQR 56-76) and 66% of patients were male. Pacific peoples were over-represented in this study population. Fifty percent had an HbA1c>60mnmol/mol and diabetes medication was changed in 50% of these. Overall, 50% of patients would be eligible for empagliflozin under current criteria.

CONCLUSIONS

High proportions of patients have poor glycaemic control and are not up-titrated, suggesting a missed opportunity for medication optimisation. Pacific peoples are over-represented in this group, suggesting that they are at high risk of diabetes and cardiovascular admissions. Empagliflozin provides a targeted way to address renal and cardiovascular outcomes.

Cardiac complications of COVID-19 infection

Since the start of the COVID-19 pandemic, studies emerged reporting the occurrence of cardiovascular complications in patients affected by SARS-CoV-2. Initial data were likely skewed by higher risk populations and those with severe disease. Recent, larger studies have corroborated this association and provide estimates for risk of cardiovascular complications. Patients affected by COVID-19 are at increased risk of myocardial infarction, myocarditis, venous thromboembolism, arrhythmias, and exacerbation of heart failure. Furthermore, a subset of patients who recover from the acute illness have persistent symptoms, a condition termed "long COVID", and management of these symptoms is challenging. Clinicians treating patients affected by COVID-19 should remain vigilant for cardiac complications during the acute illness, particularly in high-risk populations.

Revascularisation and outcomes after acute coronary syndromes in patients with prior coronary artery bypass grafting-ANZACS-QI 67

AIMS

Coronary angiography in patients with previous coronary artery bypass grafts (CABG) is technically more difficult with increased procedure time, radiation exposure and in-hospital complications. In a contemporary national registry of acute coronary syndrome (ACS) patients undergoing an invasive strategy, we compared the management and outcomes of patients with and without prior CABG.

METHODS

The All New Zealand ACS Quality Improvement (ANZACS-QI) registry was used to identify patients admitted to New Zealand public hospitals with an ACS who underwent invasive coronary angiography (2014-2018). Outcomes were ascertained by anonymised linkage to national datasets.

RESULTS

Of 26,869 patients, 1,791 (6.7%) had prior CABG and 25,078 (93.3%) had no prior CABG. Prior CABG patients were older (mean age 71 years vs 65 years), more comorbid and less likely to be revascularised than those without CABG (49.8% vs 73.0%). Compared to patients without CABG, at a mean follow-up of 2.1 years, patients with prior CABG had higher all-cause mortality (HR 2.03 (1.80-2.29)), and were more likely to have recurrent myocardial infarction (HR 2.70 (2.40-3.04)), rehospitalisation with congestive cardiac failure (HR 2.36 (2.10-2.66)) and stroke (HR 1.82 (1.41-2.34)).

CONCLUSION

In contemporary real-world practice, despite half of the patients with ACS and prior CABG receiving PCI, the outcomes remain poor compared with those without prior CABG.

Randomized evaluation of beta blocker and ACE-inhibitor/angiotensin receptor blocker treatment in patients with myocardial infarction with non-obstructive coronary arteries (MINOCA-BAT): Rationale and design

Myocardial infarction with non-obstructive coronary arteries (MINOCA) is common and occurs in 6-8% of all patients fulfilling the diagnostic criteria for acute myocardial infarction (AMI). This paper describes the rationale behind the trial 'Randomized Evaluation of Beta Blocker and ACE-Inhibitor/Angiotensin Receptor Blocker Treatment (ACEI/ARB) of MINOCA patients' (MINOCA-BAT) and the need to improve the secondary preventive treatment of MINOCA patients. METHODS: MINOCA-BAT is a registry-based, randomized, parallel, open-label, multicenter trial with 2:2 factorial design. The primary aim is to determine whether oral beta blockade compared with no oral beta blockade, and ACEI/ARB compared with no ACEI/ARB, reduce the composite endpoint of death of any cause, readmission because of AMI, ischemic stroke or heart failure in patients discharged after MINOCA without clinical signs of heart failure and with left ventricular ejection fraction ≥40%. A total of 3500 patients will be randomized into four groups; e.g. ACEI/ARB and beta blocker, beta blocker only, ACEI/ARB only and neither ACEI/ARB nor beta blocker, and followed for a mean of 4 years. SUMMARY: While patients with MINOCA have an increased risk of serious cardiovascular events and death, whether conventional secondary preventive therapies are beneficial has not been assessed in randomized trials. There is a limited basis for guideline recommendations in MINOCA. Furthermore, studies of routine clinical practice suggest that use of secondary prevention therapies in MINOCA varies considerably. Thus results from this trial may influence future treatment strategies and guidelines specific to MINOCA patients.

Left ventricular thrombus after ST segment elevation myocardial infarction: a single-centre observational study

AIMS

The incidence of left ventricular (LV) thrombus following ST segment elevation myocardial infarction (STEMI) has reduced with modern reperfusion therapies. There is scant local data on the incidence and outcomes of LV thrombus in the contemporary era of rapid reperfusion.

METHODS

Patients with STEMI admitted to Auckland City Hospital between January 2014 and December 2015 were identified using the All New Zealand Acute Coronary Syndrome Quality Improvement (ANZACS-QI) registry and their clinical notes were retrospectively reviewed.

RESULTS

Among the 997 patients admitted with STEMI, 53 patients (5%) had LV thrombus. Most patients with LV thrombus had an anterior STEMI (87%). The median time from admission to echocardiography was 48 hours (range 6-552 hours); the median LV ejection fraction was 38% (range 15-53%). Oral anticoagulation was initiated in 44 (83%) patients. LV thrombus resolved in 81% by six months in 42 patients given warfarin. Total mortality at 12 months was 13%. Bleeding occurred in 11% and was the most common treatment-related morbidity.

CONCLUSIONS

The incidence of LV thrombus following STEMI was low and it was associated with a low rate of stroke and systemic embolism but high mortality. Randomised studies are needed to evaluate the efficacy of NOAC's in this context.

The impact of a national COVID-19 lockdown on acute coronary syndrome hospitalisations in New Zealand (ANZACS-QI 55)

Background

Countries with a high incidence of coronavirus 2019 (COVID-19) reported reduced hospitalisations for acute coronary syndromes (ACS) during the pandemic. This study describes the impact of a nationwide lockdown on ACS hospitalisations in New Zealand (NZ), a country with a low incidence of COVID-19.

Methods

All patients admitted to a NZ Hospital with ACS who underwent coronary angiography in the All NZ ACS Quality Improvement registry during the lockdown (23 March – 26 April 2020) were compared with equivalent weeks in 2015–2019. Ambulance attendances and regional community troponin-I testing were compared for lockdown and non-lockdown (1 July 2019 to 16 February 2020) periods.

Findings

Hospitalisation for ACS was lower during the 5-week lockdown (105 vs. 146 per-week, rate ratio 0•72 [95% CI 0•61–0•83], p = 0.003). This was explained by fewer admissions for non-ST-segment elevation ACS (NSTE-ACS; p = 0•002) but not ST-segment elevation myocardial infarction (STEMI; p = 0•31). Patient characteristics and in-hospital mortality were similar. For STEMI, door-to-balloon times were similar (70 vs. 72 min, p = 0•52). For NSTE-ACS, there was an increase in percutaneous revascularisation (59% vs. 49%, p<0•001) and reduction in surgical revascularisation (9% vs. 15%, p = 0•005). There were fewer ambulance attendances for cardiac arrests (98 vs. 110 per-week, p = 0•04) but no difference for suspected ACS (408 vs. 420 per-week, p = 0•44). Community troponin testing was lower throughout the lockdown (182 vs. 394 per-week, p<0•001).

Interpretation

Despite the low incidence of COVID-19, there was a nationwide decrease in ACS hospitalisations during the lockdown. These findings have important implications for future pandemic planning.

Funding

The ANZACS-QI registry receives funding from the New Zealand Ministry of Health.

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.

Calibrated integrated backscatter and myocardial fibrosis in patients undergoing cardiac surgery

Objective

The reported association between calibrated integrated backscatter (cIB) and myocardial fibrosis is based on study of patients with dilated or hypertrophic cardiomyopathy and extensive (mean 15–34%) fibrosis. Its association with lesser degrees of fibrosis is unknown. We examined the relationship between cIB and myocardial fibrosis in patients with coronary artery disease.

Methods

Myocardial histology was examined in left ventricular epicardial biopsies from 40 patients (29 men and 11 women) undergoing coronary artery bypass graft surgery, who had preoperative echocardiography with cIB measurement.

Results

Total fibrosis (picrosirius red staining) varied from 0.7% to 4%, and in contrast to previous reports, cIB showed weak inverse associations with total fibrosis (r=−0.32, p=0.047) and interstitial fibrosis (r=−0.34, p=0.03). However, cIB was not significantly associated with other histological parameters, including immunostaining for collagens I and III, the advanced glycation end product (AGE) N^ε-(carboxymethyl)lysine (CML) and the receptor for AGEs (RAGE). When biomarkers were examined, cIB was weakly associated with log plasma levels of amino-terminal pro-B-type natriuretic peptide (r=0.34, p=0.03), creatinine (r=0.33, p=0.04) and glomerular filtration rate (r=−0.33, p=0.04), and was more strongly associated with log plasma levels of soluble vascular endothelial growth factor receptor-1 (sVEGFR-1) (r=0.44, p=0.01) and soluble RAGE (r=0.53, p=0.002).

Conclusions

Higher cIB was not a marker of increased myocardial fibrosis in patients with coronary artery disease, but was associated with higher plasma levels of sVEGFR-1 and soluble RAGE. The role of cIB as a non-invasive index of fibrosis in clinical studies of patients without extensive fibrosis is, therefore, questionable.

Obesity is associated with lower coronary microvascular density

Background

Obesity is associated with diastolic dysfunction, lower maximal myocardial blood flow, impaired myocardial metabolism and increased risk of heart failure. We examined the association between obesity, left ventricular filling pressure and myocardial structure.

Methods

We performed histological analysis of non-ischemic myocardium from 57 patients (46 men and 11 women) undergoing coronary artery bypass graft surgery who did not have previous cardiac surgery, myocardial infarction, heart failure, atrial fibrillation or loop diuretic therapy.

Results

Non-obese (body mass index, BMI, ≤30 kg/m², n=33) and obese patients (BMI >30 kg/m², n=24) did not differ with respect to myocardial total, interstitial or perivascular fibrosis, arteriolar dimensions, or cardiomyocyte width. Obese patients had lower capillary length density (1145±239, mean±SD, vs. 1371±333 mm/mm³, P=0.007) and higher diffusion radius (16.9±1.5 vs. 15.6±2.0 μm, P=0.012), in comparison with non-obese patients. However, the diffusion radius/cardiomyocyte width ratio of obese patients (0.73±0.11 μm/μm) was not significantly different from that of non-obese patients (0.71±0.11 μm/μm), suggesting that differences in cardiomyocyte width explained in part the differences in capillary length density and diffusion radius between non-obese and obese patients. Increased BMI was associated with increased pulmonary capillary wedge pressure (PCWP, P<0.0001), and lower capillary length density was associated with both increased BMI (P=0.043) and increased PCWP (P=0.016).

Conclusions

Obesity and its accompanying increase in left ventricular filling pressure were associated with lower coronary microvascular density, which may contribute to the lower maximal myocardial blood flow, impaired myocardial metabolism, diastolic dysfunction and higher risk of heart failure in obese individuals.

Impact of type 2 diabetes and the metabolic syndrome on myocardial structure and microvasculature of men with coronary artery disease

Background

Type 2 diabetes and the metabolic syndrome are associated with impaired diastolic function and increased heart failure risk. Animal models and autopsy studies of diabetic patients implicate myocardial fibrosis, cardiomyocyte hypertrophy, altered myocardial microvascular structure and advanced glycation end-products (AGEs) in the pathogenesis of diabetic cardiomyopathy. We investigated whether type 2 diabetes and the metabolic syndrome are associated with altered myocardial structure, microvasculature, and expression of AGEs and receptor for AGEs (RAGE) in men with coronary artery disease.

Methods

We performed histological analysis of left ventricular biopsies from 13 control, 10 diabetic and 23 metabolic syndrome men undergoing coronary artery bypass graft surgery who did not have heart failure or atrial fibrillation, had not received loop diuretic therapy, and did not have evidence of previous myocardial infarction.

Results

All three patient groups had similar extent of coronary artery disease and clinical characteristics, apart from differences in metabolic parameters. Diabetic and metabolic syndrome patients had higher pulmonary capillary wedge pressure than controls, and diabetic patients had reduced mitral diastolic peak velocity of the septal mitral annulus (E'), consistent with impaired diastolic function. Neither diabetic nor metabolic syndrome patients had increased myocardial interstitial fibrosis (picrosirius red), or increased immunostaining for collagen I and III, the AGE Nε-(carboxymethyl)lysine, or RAGE. Cardiomyocyte width, capillary length density, diffusion radius, and arteriolar dimensions did not differ between the three patient groups, whereas diabetic and metabolic syndrome patients had reduced perivascular fibrosis.

Conclusions

Impaired diastolic function of type 2 diabetic and metabolic syndrome patients was not dependent on increased myocardial fibrosis, cardiomyocyte hypertrophy, alteration of the myocardial microvascular structure, or increased myocardial expression of Nε-(carboxymethyl)lysine or RAGE. These findings suggest that the increased myocardial fibrosis and AGE expression, cardiomyocyte hypertrophy, and altered microvasculature structure described in diabetic heart disease were a consequence, rather than an initiating cause, of cardiac dysfunction.

Screening for left ventricular hypertrophy in patients with type 2 diabetes mellitus in the community

BACKGROUND

Left ventricular hypertrophy (LVH) is a strong predictor of cardiovascular disease and is common among patients with type 2 diabetes. However, no systematic screening for LVH is currently recommended for patients with type 2 diabetes. The purpose of this study was to determine whether NT-proBNP was superior to 12-lead electrocardiography (ECG) for detection of LVH in patients with type 2 diabetes.

METHODS

Prospective cross-sectional study comparing diagnostic accuracy of ECG and NT-proBNP for the detection of LVH among patients with type 2 diabetes. Inclusion criteria included having been diagnosed for > 5 years and/or on treatment for type 2 diabetes; patients with Stage 3/4 chronic kidney disease and known cardiovascular disease were excluded. ECG LVH was defined as either the Sokolow-Lyon or Cornell voltage criteria. NT-proBNP level was measured using the Roche Diagnostics Elecsys assay. Left ventricular mass was assessed from echocardiography. Receiver operating characteristic curve analysis was carried out and area under the curve (AUC) was calculated.

RESULTS

294 patients with type 2 diabetes were recruited, mean age 58 (SD 11) years, BP 134/81 ± 18/11 mmHg, HbA 1c 7.3 ± 1.5%. LVH was present in 164 patients (56%). In a logistic regression model age, gender, BMI and a history of hypertension were important determinants of LVH (p < 0.05). Only 5 patients with LVH were detected by either ECG voltage criteria. The AUC for NT-proBNP in detecting LVH was 0.68.

CONCLUSIONS

LVH was highly prevalent in asymptomatic patients with type 2 diabetes. ECG was an inadequate test to identify LVH and while NT-proBNP was superior to ECG it remained unsuitable for detecting LVH. Thus, there remains a need for a screening tool to detect LVH in primary care patients with type 2 diabetes to enhance risk stratification and management.

Differences in myocardial structure and coronary microvasculature between men and women with coronary artery disease

Women younger than 75 years with stable angina or acute coronary syndrome have higher cardiac mortality than similarly aged men, despite less obstructive coronary artery disease. To determine whether the myocardial structure and coronary microvasculature of women differs from that of men, we performed histological analysis of biopsies from nonischemic left ventricular myocardium from 46 men and 11 women undergoing coronary artery bypass graft surgery who did not have previous cardiac surgery, myocardial infarction, heart failure, atrial fibrillation, or furosemide therapy. The 2 patient groups had similar clinical characteristics, apart from a lower body surface area (BSA) in women (P = 0.0015). Women had less interstitial fibrosis than men (P = 0.019) but similar perivascular fibrosis. Arteriolar wall area/circumference ratio, a measure of arteriolar wall thickness, was 47% greater in women than men (P = 0.012). Cardiomyocyte width and diffusion radius were positively correlated, and capillary length density was negatively correlated with BSA (P < 0.05). Whereas cardiomyocyte width, capillary length density, diffusion radius, and cardiomyocyte width/BSA ratio were similar for men and women, women had a greater diffusion radius/BSA ratio (P = 0.0038) and a greater diffusion radius/cardiomyocyte width ratio (P = 0.027). Women also had lower vascular endothelial growth factor (VEGF) receptor-1 levels (P = 0.048) and VEGF receptor-1/VEGF-A ratio (P = 0.024) in plasma. We conclude that women with extensive coronary artery disease have greater arteriolar wall thickness and diffusion radius relative to BSA and to cardiomyocyte width than men, which may predispose to myocardial ischemia. Additional studies of larger numbers of women with less extensive coronary artery disease are required to confirm these findings.

Role of echocardiographic left ventricular mass and carotid intima-media thickness in the cardiovascular risk assessment of asymptomatic patients with type 2 diabetes mellitus

BACKGROUND

Standard cardiovascular (CV) risk assessment may underestimate risk in people with type 2 diabetes mellitus (T2DM). Cardiac and vascular imaging to detect subclinical disease may augment risk prediction. This study investigated the association between CV risk, left ventricular hypertrophy (LVH) and carotid intima-media thickness (CIMT) in patients with T2DM free of CV symptoms.

METHODS

People with T2DM without known CV disease were recruited from general practice. The 5-year risk of CV events was calculated using an adjusted Framingham equation and the prevalence of LVH and abnormal CIMT across bands of CV risk assessed. In those at intermediate risk, the number needed to scan (NNS) to reclassify one person to high risk was calculated across the group and compared in those above and below 55 years. The association between LV mass and CIMT was also assessed.

RESULTS

Mean age 57 years (SD11), 51% female. Median 5-year CV risk 14.3% (interquartile range 10.3, 19.5), 51% had LVH (American Society of Echocardiography criteria) and 31% an abnormal CIMT (age and sex criteria). In the 52% at intermediate risk, 37% had LVH and 36% an abnormal CIMT. The NNS was 1.7 using both imaging techniques, 2.7 using cardiac imaging alone or 2.8 using vascular imaging alone. Almost twice as many people >55 years had an abnormal CIMT than those <55 years.

CONCLUSIONS

Cardiac and vascular imaging to detect subclinical disease can be used to augment prediction of CV risk in people with T2DM at intermediate risk. The value of reclassifying risk is as yet unproven and requires outcome data from intervention studies.

The prognostic significance of heart failure with preserved left ventricular ejection fraction: a literature-based meta-analysis

AIMS

Heart failure (HF) with normal or preserved left ventricular (LV) ejection fraction (HFPEF) has been reported to be associated with similar outcome as HF with reduced EF (HFREF) in registry-based and epidemiological analyses, but many of these studies excluded patients who did not have EF measurements. Conversely, prior prospective studies have reported better outcome for patients with HFPEF. We performed a meta-analysis of prospective observational studies comparing all-cause mortality in patients with HFREF and HFPEF.

METHODS AND RESULTS

We searched several online databases for studies comparing outcome in HFREF and HFPEF, published before 2007.

INCLUSION CRITERIA

prospective, clinical HF, near complete EF data, and mortality outcome. Review Manager version 4.2.3 software was used for the analysis. Overall, 24 501 patients [9299 deaths (38%)] from 17 studies are included. Average follow-up was 47 months; the HFPEF group was older (69 vs. 66 years) and more likely to be female (44% vs. 26%). Of the 7688 patients with HFPEF 2468 died (32.1%), compared with 6831 of the 16 813 patients with HFREF (40.6%): odds ratio 0.51 (95% CI: 0.48, 0.55).

CONCLUSION

This literature-based meta-analysis demonstrates that mortality among patients with HFPEF was half that observed in those with HFREF, in contrast to previous reports suggesting that mortality may be similar between both groups.

Restrictive Filling Pattern is a Powerful Predictor of Heart Failure Events Postacute Myocardial Infarction and in Established Heart Failure: A Literature-Based Meta-Analysis

BACKGROUND

Two recent literature-based meta-analyses revealed that restrictive filling pattern (RFP) was associated with a 4-fold increase in the risk of death in patients with heart failure (HF) and postacute myocardial infarction (AMI). This similar but unique analysis evaluated the link between RFP and morbidity.

METHODS AND RESULTS

Prospective echocardiographic studies of patients post-AMI and with HF that reported HF morbidity were identified. Events (post-AMI: development of HF; HF: HF readmission) were compared between patients with and without RFP in both patient groups. Review Manager version 4.2.7 software was used for the analysis. Twelve post-AMI studies (1286 patients, 271 events) and 5 HF studies (647 patients, 176 events) were identified. RFP was associated with HF readmission in the HF patients (OR 2.96 [2.02-4.33] and development of HF post-AMI (OR 10.10 [7.02-14.51]). The event rate in the RFP group was the same regardless of disease category (49% post-AMI, 42% HF); however, RFP was less prevalent in the post-AMI group (22% versus 39%).

CONCLUSIONS

This literature-based meta-analysis confirms that RFP is a powerful predictor of HF hospitalization in patients with HF and especially the development of HF post-AMI. This is an important prognostic sign and should be incorporated into routine clinical practice.