Individual lifetime benefit from low-dose colchicine in chronic coronary artery disease patients

Background

Low-dose colchicine reduces the risk of cardiovascular events in patients with chronic coronary artery disease (CAD), but the absolute benefit may vary between patients. Individual benefit from preventive therapies can be estimated using the guideline-recommended SMART-REACH model.

Purpose

This study aimed to assess the range of individual absolute 10-year and lifetime benefit from low-dose colchicine according to patient risk profile.

Methods

The SMART-REACH model was combined with the relative treatment effect of low-dose colchicine, and applied to all participants from the LoDoCo2 trial (n=5,522), and patients with chronic CAD from the UCC-SMART cohort (n=5,308). Individual treatment benefit was expressed as (i) 10-year absolute risk reductions (ARRs) for myocardial infarction, ischemic stroke, or cardiovascular death (MACE), and (ii) life-years gained free of MACE. Predictions were also performed for MACE plus ischemia-driven coronary revascularization (MACE+), through development of a new competing risk-adjusted lifetime prediction model in data from the REACH registry (n=14,522). Low-dose colchicine was compared to alternative intensive prevention goals, i.e. low density lipoprotein-cholesterol (LDL-c) reduction to <1.4 mmol/L, and systolic blood pressure (SBP) reduction to <130 mmHg.

Results

Median individual 10-year ARR for MACE from low-dose colchicine therapy was 4.6% (interquartile range [IQR] 3.6–6.0%), and median gain in life expectancy free of MACE was 2.0 (IQR 1.6–2.5) years. Median 10-year ARR for MACE+ was 8.6% (IQR 7.6–9.8%), and median gain in MACE+-free life expectancy was 3.4 (IQR 2.6–4.2) years. For intensified LDL-c and SBP reduction respectively, median 10-year ARRs were 3.0% (IQR 1.5–5.1%) and 1.7% (IQR 0.0–5.7%) for MACE, and 5.2% (IQR 2.5–8.7%) and 2.9% (IQR 0.0–9.5%) for MACE+. Median life-years gained from LDL-c and SBP reduction were 1.2 (IQR 0.6–2.1) and 0.7 (IQR 0.0–2.3) years free of MACE, and 1.8 (IQR 0.8–3.3) and 0.9 (IQR 0.0–3.4) years free of MACE+.

Conclusion

The individual absolute benefit from low-dose colchicine varies between patients. In an era where lipid- and blood pressure-lowering therapies are already routinely used, the benefits of low-dose colchicine are expected to be of at least similar magnitude to those of intensified LDL-c and SBP reduction in patients with chronic CAD.

Funding Acknowledgement

Type of funding sources: None.

Burden of stroke incidence among atrial fibrillation, valvular heart disease and coronary heart disease patients

Funding Acknowledgements

Type of funding sources: Public grant(s) – National budget only. Main funding source(s): National Health and Medical Research Council of Australia

Background

The public health burden of stroke has continued to increase in recent decades. In patients with cardiac disease, the risk of stroke is 2-4 times higher than in the general population, and therefore investigating stroke incidence in these patients is important for identifying opportunities for stroke prevention.

Purpose

We aimed to measure the incidence of stroke in people with atrial fibrillation (AF), valvular heart disease (VHD) or coronary heart disease (CHD) to assess the risk of stroke by age, sex, pre-existing vs new cardiac disease, and nonfatal/fatal status.

Methods

We used a person-linked hospitalisation/mortality dataset to identify all people hospitalized with AF, VHD or CHD from 1985 to 2017 in a whole-population setting. These cardiac cases were stratified as pre-existing (hospitalised between 1985 and 2012, who were alive at 31st October 2012 with no history of stroke) or new (first-ever cardiac hospitalisation from November 1st, 2012 to October 31st, 2017, with no prior hospitalisation for AF, VHD or CHD, and no history of stroke). Patients aged 20-94 years were included in the study. Pre-existing and new cardiac cases were followed over the 5-year study period (1st November 2012 to 31st December 2017) to identify first-ever stroke events. Age-specific and age-standardised rates (ASR) for stroke incidence were calculated for all cardiac cases combined, and separately for pre-existing and new cases.

Results

The cohort comprised 175,560 patients. The majority of the cohort had a single cardiac condition (55.7% CHD; 23.0% AF; 5.0% VHD), while 16.3% of patients had multiple cardiac conditions. There were 5,871 (3.3%) first-ever strokes (5.2% in AF patients, 4.0% in VHD, 2.8% in CHD). Stroke incidence ASRs were greater in women than men across each cardiac group and irrespective of the presence of single or multiple cardiac conditions (Figure). This was largely driven by women aged ≥75 years, with stroke incidence being greater in women than men in each cardiac group. In women aged 20-54 years, there was a 4.9-fold higher incidence of stroke in those with multiple versus single cardiac conditions, and this differential appeared to decline with increasing age (Figure). Incidence of non-fatal strokes was greater than fatal stroke in all age groups except among 85-94 year olds. Incidence rates in each cardiac group were between 1.2 and 2.4 times higher in those with new versus pre-existing cardiac disease.

Conclusions

Stroke incidence is substantial in patients with cardiac disease. Older women with AF and VHD had the highest stroke rates overall, although younger patients with multiple cardiac conditions were also at high risk. These cardiac patients should be targeted for evidence-based management to minimise their stroke risk, especially in the period immediately following diagnosis when risk is highest.

Figure Legend. Age-specific and age-standardised stroke incidence rates in all cardiac cases.

12-month post-trial follow-up of participants in the Australian arm of the second low-dose colchicine trial

Background

In the Australian arm of the LoDoCo2 trial, colchicine 0.5mg daily compared with placebo markedly reduced the risk of cardiovascular (CV) events in patients with chronic coronary disease (2.0 vs 3.9 events per 100 person years, HR 0.51; 95% CI 0.39–0.67). The purpose of this analysis was to explore CV and non-CV outcomes in the Australian cohort out to one year after cessation of trial medication.

Methods

Information was collected on all potential CV events and non-CV deaths as well as a range of other co-morbidities. All CV events were blindly adjudicated. The analysis examined the primary outcome (a composite of CV death, myocardial infarction, ischemic stroke, and unscheduled revascularization) and non-CV deaths by initial randomized treatment from the beginning of the trial up until one year after cessation of trial medication. A landmark analysis was then used to examine these outcomes from the date of last contact during the trial until one year after cessation of trial medication.

Results

The clinical status was confirmed in 1819/1824 (99.7%) participants who were alive at the end of the trial, and in 100% of those participants still taking trial medication at the end of the trial. During post-trial follow up, 515 patients (28.2%) were taking non-study colchicine, including 278 (30.5%) originally randomized to colchicine and 237 (25.9%) randomized to placebo. Over the entire follow-up period that included the 12-month period after the trial medication was ceased, the effect of prior exposure to colchicine on the primary CV outcome was still evident (2.2 vs 3.8 events per 100 person years, HR 0.58; 95% CI 0.45–0.74), however no post-trial CV benefit were apparent in the landmark analysis (3.3 vs 3.4 events per 100 person years, HR 0.97; 95% CI 0.56–0.1.69). Over the entire course of follow-up the incidence of new cancer (7.9% vs 7.2% RR 0.91; 95% CI 0.66–1.25) and non-CV death (0.9 vs 0.6 events per 100 person years, HR 1.44; 95% CI 0.92–2.27) was no different in the treatment groups.

Conclusion

Although the CV benefits of colchicine treatment that emerged during the trial were still evident in the year after stopping study treatment, no additional CV benefit accrued after it was ceased. These data suggest that colchicine should be continued long-term to maximize its CV benefits.

Funding Acknowledgement

Type of funding sources: None.

Prognostic value of pulmonary transit time by cardiac magnetic resonance in patients with heart failure with preserved ejection fraction

Funding Acknowledgements

Type of funding sources: Other. Main funding source(s): National Institute for Health Research Leicester Cardiovascular Biomedical Research Centre

Background

Quantifying pulmonary transit time (PTT) from cardiac magnetic resonance (CMR) first pass perfusion imaging is a novel technique for the evaluation of haemodynamic congestion in heart failure. Previous studies have demonstrated that PTT is prolonged in patients with heart failure with reduced ejection fraction (HFrEF) and that it provides independent prognostic information in this patient group. However, the potential diagnostic and prognostic roles of PTT assessment in patients with heart failure with preserved ejection fraction (HFpEF) remain to be established.

Aim

To compare PTT in healthy controls and in patients with HFpEF, and to determine the prognostic value of PTT in HFpEF.

Methods

In a prospective, observational study, HFpEF and age-matched control subjects underwent multi-parametric CMR at 3-Tesla, comprising quantitative left ventricular volumetric assessment using a standard steady-state free precession (SSFP) pulse sequence, and first-pass perfusion imaging at rest using a T1-weighted segmented inversion recovery gradient echo sequence (following injection of 0.04mmol/kg of contrast). PTT was calculated as the time interval between the peaks of signal intensity curves in the right and left ventricular blood pools (defined on the basal slice of the rest perfusion images). The primary endpoint was the composite of death or hospitalisation with heart failure.

Results

88 HFpEF patients (age 73 ± 9 years, 51% male, EF 56.4 ± 5.6%) and 40 controls (age 73 ± 5 years, 43% male, EF 58.5 ± 4.7%) were studied. PTT was comparable in HFpEF patients (7.7 ± 3.8s) and in healthy controls (7.5 ± 1.8, p = 0.69). Normalised to cardiac cycle lengths, PTT remained comparable in HFpEF patients and healthy controls (8.5 ± 4.0 cardiac cycles versus 7.8 ± 1.6 cardiac cycles, respectively, p = 0.19). In the HFpEF group, during median follow-up of 3.4 years, there were 38 events (25 hospitalisations with heart failure, 13 deaths); a significant relationship between survival and PTT was not demonstrated (HR 1.06 [0.99,1.14] for a one-unit increase, p = 0.098).

Conclusion

In HFpEF, PTT is not prolonged compared with PTT in healthy subjects. Unlike in HFrEF, PTT does not appear to be diagnostically or prognostically significant in HFpEF.

Figure 1: Graph showing signal intensity curves in the right (red) and left (green) ventricular blood pools

Figure 2: Kaplan-Meier plot showing comparable rates of the composite endpoint in patients with PTT greater/less than median PTT (8 cardiac cycles)

Cardiovascular magnetic resonance to predict clinical outcome in chronic total coronary artery occlusion

Background

Chronic total coronary artery occlusions (CTOs) are present in approximately 20–30% of patients undergoing invasive angiography. Despite their prevalence, the optimum management strategy of CTOs remains uncertain. A potential limitation in published trials of CTO revascularisation is their failure to incorporate systematic assessment of ischaemia/viability in informing revascularisation decisions.

Aim

We sought to determine the prognostic utility of ischaemia/viability assessment by cardiovascular magnetic resonance (CMR) in a large, contemporaneous, real-world CTO population.

Methods

We retrospectively studied consecutive adult patients with≥1angiographically identified CTO who were referred for clinical CMR imaging during a consecutive 8-year period in our centre (2010–2018). Multi-parametric CMR comprised functional assessment, adenosine-stress perfusion and scar imaging. For perfusion assessment, images were analysed qualitatively with a concurrent examination of scar images. Myocardial segments were assigned to CTO or non-CTO territories according to standard criteria, taking into account coronary dominance. Significant ischaemia was defined as ≥10% and/or ≥2 contiguous myocardial segments with hibernation. Angiographic collateral flow to the CTO territory was graded using the Rentrop classification and the Collateral Connection (CC) Score. Significant CAD in non-CTO vessels was defined angiographically as ≥50% stenosis in any epicardial coronary artery/branch with diameter ≥2mm. The composite clinical endpoint comprised all-cause mortality, myocardial infarction and heart failure hospitalisation.

Results

From a total of 27,201 invasive angiograms performed during the study period, 389 patients were diagnosed with CTO and underwent CMR imaging (mean age 65.0±11.0 years, 84% male). CTO was present most frequently in the right coronary artery (59% of subjects, 229/389), with left circumflex (LCx) artery involvement in 29% (112/389) and left anterior descending (LAD) artery in 29% (111/389). Collaterals with CC grade ≥2 were identified in 186 subjects (48%), and Rentrop score ≥2 in 300 (77%). Significant ischaemia was present in 61% of patients, and infarction in 71% (median infarction 8.6% [interquartile range (IQR) 4.5–14.1]. With a median follow-up time of 3.30 years [IQR 0.04–8.64], 65 (17%) met the composite endpoint. On multivariate analysis, neither significant ischaemia nor infarction was associated with the composite endpoint. However, non-CTO territory ischaemia was independently predictive of adverse outcome (hazard ratio 1.93; 95% CI 1.16–3.21; p=0.0113).

Conclusion

CTO-territory ischaemia and infarction are not predictive of adverse clinical outcome, challenging the assertion that CTO revascularisation may be guided by ischaemia assessment. The finding that non-CTO territory ischaemia is associated with adverse cardiovascular events warrants further investigation.

Kaplan-Meier curves_CTO

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): British Heart Foundation

Spontaneous coronary artery dissection: novel pathophysiological insights from histological and ultrastructural tissue analysis

Introduction

Spontaneous coronary artery dissection (SCAD) is a cause of acute coronary syndromes and rarely sudden cardiac death (SCD). SCAD is characterised by medial false lumen haematoma formation and periadventitial inflammatory cell infiltrate. Although SCAD has been linked to connective tissue disorders, its pathophysiology remains poorly understood and the role of inflammation unknown.

Purpose

We sought to establish the definitive histopathological features of SCAD and explore pathophysiological mechanisms through assessment of dermal connective tissue ultrastructure.

Methods

N=36 SCD cases diagnosed as SCAD on autopsy were identified in pathology archives at four international centres. Their demographic and clinical characteristics were compared with n=359 survivors recruited in a SCAD survivors cohort. Haematoxylin & eosin sections were examined under light microscope. Immunohistochemistry (IHC) was employed for quantification of inflammatory cell infiltrate (CD68, CD3) and vasa vasorum density (CD31) of SCAD cases (n=20) compared to age- and sex-matched controls (n=10). Dermal extracellular matrix components (EMC) of n=32 SCAD survivors and n=16 healthy volunteers (HV) were compared using electron microscopy (EM).

Results

The autopsy series cases were more likely to be male (p=0.0256) and had higher incidence of left main stem (p=0.0475) and proximal left anterior descending (p<0.001) disease compared to SCAD survivors. N=24 (66%) of SCAD autopsy case showed no evidence of myocardial necrosis. N=17 (47%) showed mild-moderate atherosclerotic changes but no features of fibromuscular dysplasia. There were no differences in vasa vasorum density between SCAD and control cases (A). The degree of inflammatory cell infiltrate varied greatly but significantly higher than controls (B), comprising CD68+ macrophages, eosinophils and CD3+ positive T-cells. There was a statistically significant association (p=0.006) between the degree of inflammatory cell infiltrate and the length of time from onset of symptoms to death (Panel C), as well as significantly (p<0.001) denser inflammatory cell infiltrate adjacent to the dissection plane (D, exemplary sections E&F). EM revealed no differences between SCAD and HV in dermal fibroblast size & activity or elastin size & damage indicators, but possible changes in subgroups with more extreme clinical phenotype or pregnancy-related SCAD (G).

Conclusions

To our knowledge this is the largest SCAD pathology case series so far. We show for the first time that periadvential inflammation in SCAD appears to be time-dependent and localising to the dissected coronary segment, suggesting healing response to injury rather than causal contribution. We found no evidence to suggest increased vasa vasorum density is pathophysiologically important. Connective tissue changes were only linked to a small proportion of cases. These novel findings may have important implications for the management of SCAD patients.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): British Heart Foundation, Leicester NIHR Biomedical Research Centre

INFOMATAS multi-center systematic review and meta-analysis individual patient data of dynamic cerebral autoregulation in ischemic stroke

Rationale

Disturbances in dynamic cerebral autoregulation after ischemic stroke may have important implications for prognosis. Recent meta-analyses have been hampered by heterogeneity and small samples.

Aim and/or hypothesis

The aim of study is to undertake an individual patient data meta-analysis (IPD-MA) of dynamic cerebral autoregulation changes post-ischemic stroke and to determine a predictive model for outcome in ischemic stroke using information combined from dynamic cerebral autoregulation, clinical history, and neuroimaging.

Sample size estimates

To detect a change of 2% between categories in modified Rankin scale requires a sample size of ∼1500 patients with moderate to severe stroke, and a change of 1 in autoregulation index requires a sample size of 45 healthy individuals (powered at 80%, α = 0.05). Pooled estimates of mean and standard deviation derived from this study will be used to inform sample size calculations for adequately powered future dynamic cerebral autoregulation studies in ischemic stroke.

Methods and design

This is an IPD-MA as part of an international, multi-center collaboration (INFOMATAS) with three phases. Firstly, univariate analyses will be constructed for primary (modified Rankin scale) and secondary outcomes, with key co-variates and dynamic cerebral autoregulation parameters. Participants clustering from within studies will be accounted for with random effects. Secondly, dynamic cerebral autoregulation variables will be validated for diagnostic and prognostic accuracy in ischemic stroke using summary receiver operating characteristic curve analysis. Finally, the prognostic accuracy will be determined for four different models combining clinical history, neuroimaging, and dynamic cerebral autoregulation parameters.

Study outcome(s)

The outcomes for this study are to determine the relationship between clinical outcome, dynamic cerebral autoregulation changes, and baseline patient demographics, to determine the diagnostic and prognostic accuracy of dynamic cerebral autoregulation parameters, and to develop a prognostic model using dynamic cerebral autoregulation in ischemic stroke.

Discussion

This is the first international collaboration to use IPD-MA to determine prognostic models of dynamic cerebral autoregulation for patients with ischemic stroke.