Cardiac evaluation for end-stage kidney disease patients on the transplant waitlist: a single-center cohort study

Background

Cardiac evaluation before deceased donor kidney transplant (DDKT) remains a matter of debate. Data on Asian countries and countries with prolonged waiting times are lacking. This study aimed to assess the outcomes of patients referred for DDKT after a cardiac evaluation at an Asian tertiary transplant center.

Methods

This single-center retrospective review analyzed patients who were referred for waitlist placement and underwent cardiac stress testing between January 2009 and December 2015. Patients with cardiac symptoms were excluded. The primary outcome was three-point major adverse cardiovascular events (MACE), a composite of non-fatal myocardial infarction, non-fatal stroke, and cardiovascular death.

Results

Of 468 patients referred for DDKT, 198 who underwent cardiac stress testing (myocardial perfusion studies in 159 patients and stress echocardiography in 39 patients) were analyzed. MACE occurred in 20.7% of the patients over a median follow-up of 4.6 years. Cardiac stress tests were positive for ischemia in 19.7% of the patients. Coronary angiography was performed in 63 patients, including 29 patients with diabetic kidney disease and negative cardiac stress tests. Significant coronary artery disease (CAD) was detected in 27 patients (42.8%), of whom 18 underwent revascularization. MACE was associated with significant CAD on coronary angiography in the multivariable analysis. Cardiac stress test results were not associated with MACE. Amongst diabetic patients who had negative cardiac stress tests, 37.9% had significant CAD on coronary angiography.

Conclusions

The cardiovascular disease burden is significant amongst DDKT waitlist candidates. Pretransplant cardiac screening may identify patients with significant CAD at higher risk of MACE.

Prevalence and distribution of coronary artery calcium in a southeast asian cohort

Funding Acknowledgements

Type of funding sources: None.

Background

The coronary artery calcium score (CACS) independently predicts the risk of cardiovascular disease and major adverse cardiovascular events. While previous studies have demonstrated regional and ethnic differences in coronary calcification, the distribution of CACS in Southeast Asian (SEA) adults has not been investigated.

Purpose

The aim of this study was to determine CACS distribution in a SEA cohort living in Singapore.

Methods

This study involved 4945 asymptomatic patients who underwent CT coronary angiography and calcium scoring as part of screening for cardiovascular disease. Similar to the MESA study, patients with diabetes were analyzed separately due an increased prevalence of coronary calcification. A nonparametric analytical approach was used to determine CACS distribution stratified by age, gender and ethnicity.

Results

A positive CACS was seen in 43.7% of the overall SEA cohort with a higher prevalence in males (45.2%) than females (36.7%). The onset and burden of coronary calcification was also earlier and more severe in male subjects. There were no significant differences in CACS distribution amongst the three major ethnic groups in our study (p = 0.177). The presence of coronary calcification (CACS >0) was associated with increasing age, male gender and hypertension. Ethnicity, dyslipidemia, smoking and a family history of coronary artery disease did not significantly affect the presence of CACS.

Conclusions

This study provides a reference CACS distribution in an asymptomatic SEA population. There were no significant differences in CACS distribution amongst the three major ethnic groups living in Singapore.

Patterns of motivators and barriers to heart health behaviors among adults with behavior-modifiable cardiovascular risk factors: A population-based survey in Singapore

OBJECTIVES

Motivators and barriers are pivotal factors in the adoption of health behaviors. This study aims to identify patterns of the motivators and barriers influencing heart health behaviors among multi-ethnic Asian adults with behavior-modifiable risk factors for heart disease, namely obesity, physical inactivity and smoking.

METHODS

A population-based survey of 1,000 participants was conducted in Singapore. Participants were assessed for behavior-modifiable risk factors and asked about motivators and barriers to heart health behaviors. Exploratory and confirmatory factor analyses were conducted to identify factors underlying motivator and barrier question items. Logistic regression was conducted to examine the associations of motivator and barrier factors with sociodemographic characteristics.

RESULTS

The twenty-five motivator and barrier items were classified into three (outcome expectations, external cues and significant others including family and friends) and four (external circumstances, limited self-efficacy and competence, lack of perceived susceptibility, benefits and intentions and perceived lack of physical capability) factors respectively. Among participants with behavior-modifiable risk factors, those with lower education were more likely to be low in motivation factor of "outcome expectations" and "external cues". The well-educated were more likely to be high in the barrier factor of "lack of perceived susceptibility, benefits and intention" and were less likely to have the motivation factor of "significant others (family or friends)". Those aged 60-75 years had low motivations and high barriers compared to their younger counterparts. Older age was more likely to be low in motivation factor of "outcome expectations" and "external cues" and high in barrier factor of "limited self-efficacy and competence" and "perceived lack of physical capability".

CONCLUSIONS

Findings underscore the importance of a targeted intervention and communication strategy addressing specific motivation and barrier factors in different population segments with modifiable risk factors.

Performance of the coronary calcium score in an outpatient chest pain clinic and strategies for risk stratification

Background

Coronary artery calcium score (CAC) is an objective marker of atherosclerosis. The primary aim is to assess CAC as a risk classifier in stable coronary artery disease (CAD).

Hypothesis

CAC improves CAD risk prediction, compared to conventional risk scoring, even in the absence of cardiovascular risk factor inputs.

Methods

Outpatients presenting to a cardiology clinic (n = 3518) were divided into two cohorts: derivation (n = 2344 patients) and validation (n = 1174 patients). Adding logarithmic transformation of CAC, we built two logistic regression models: Model 1 with chest pain history and risk factors and Model 2 including chest pain history only without risk factors simulating patients with undiagnosed comorbidities. The CAD I Consortium Score (CCS) was the conventional reference risk score used. The primary outcome was the presence of coronary artery disease defined as any epicardial artery stenosis≥50% on CT coronary angiogram.

Results

Area under curve (AUC) of CCS in our validation cohort was 0.80. The AUC of Models 1 and 2 were significantly improved at 0.88 (95%CI 0.86–0.91) and 0.87 (95%CI 0.84–0.90), respectively. Integrated discriminant improvement was >15% for both models. At a pre‐specified cut‐off of ≤10% for excluding coronary artery disease, the sensitivity and specificity were 89.3% and 74.7% for Model 1, and 88.1% and 71.8% for Model 2.

Conclusion

CAC helps improve risk classification in patients with chest pain, even in the absence of prior risk factor screening.

Calibration of a physical functioning item bank for measurement of health-related quality of life in Singapore

PURPOSE

We aimed to develop and calibrate an item bank to measure physical function (PF) in Singapore, a multi-ethnic city in Southeast Asia.

METHODS

We recruited participants from community and hospital settings stratified for age and gender, with and without medical conditions to administer candidate pool of 61-items derived from the people's perspectives. We calibrated their responses using Samejima's graded response model of item response theory (IRT), including model assumptions, model fit, differential item functioning (DIF), and concurrent and known-groups validity.

RESULTS

496 participants (50% male; 41% above 50 years old; 33.3% Chinese, 32.7% Malay and 34.1% Indian; 35% without chronic illness) were included in the calibration of item bank. 6 items were excluded due to mis-fit and local dependence. Redundancies in the response level was collapsed and re-scoring, while preserving the 5-level response structure. We found the final 55-item PF bank had adequate fit to IRT assumptions of unidimensionality, local independence and monotonicity. Items generally showed discernible ceiling effects with latent scores between - 3.5 to + 1.5. We found no DIF with gender, ethnicity or education. The PF scores correlated in the hypothesized direction with self-reported global health (Spearman's rho =  - 0.35, 95% confidence intervals - 0.43 to - 0.27) and discriminated between groups stratified by age, gender and medical conditions.

CONCLUSION

The 55-item Singapore PF item bank provides an adequate tool for measuring the lower end of PF, with greatest potential utility in healthcare settings where restoration to normal physical functioning is the goal of intervention.

The Lipid Paradox is present in ST-elevation but not in non-ST-elevation myocardial infarction patients: Insights from the Singapore Myocardial Infarction Registry

Lowering low-density lipoprotein (LDL-C) and triglyceride (TG) levels form the cornerstone approach of cardiovascular risk reduction, and a higher high-density lipoprotein (HDL-C) is thought to be protective. However, in acute myocardial infarction (AMI) patients, higher admission LDL-C and TG levels have been shown to be associated with better clinical outcomes - termed the ‘lipid paradox’. We studied the relationship between lipid profile obtained within 72 hours of presentation, and all-cause mortality (during hospitalization, at 30-days and 12-months), and rehospitalization for heart failure and non-fatal AMI at 12-months in ST-segment elevation myocardial infarction (STEMI) and non-ST-segment elevation myocardial infarction (NSTEMI) patients treated by percutaneous coronary intervention (PCI). We included 11543 STEMI and 8470 NSTEMI patients who underwent PCI in the Singapore Myocardial Infarction Registry between 2008–2015. NSTEMI patients were older (60.3 years vs 57.7 years, p < 0.001) and more likely to be female (22.4% vs 15.0%, p < 0.001). In NSTEMI, a lower LDL-C was paradoxically associated with worse outcomes for death during hospitalization, within 30-days and within 12-months (all p < 0.001), but adjustment eliminated this paradox. In contrast, the paradox for LDL-C persisted for all primary outcomes after adjustment in STEMI. For NSTEMI patients, a lower HDL-C was associated with a higher risk of death during hospitalization but in STEMI patients a lower HDL-C was paradoxically associated with a lower risk of death during hospitalization. For this endpoint, the interaction term for HDL-C and type of MI was significant even after adjustment. An elevated TG level was not protective after adjustment. These observations may be due to differing characteristics and underlying pathophysiological mechanisms in NSTEMI and STEMI.

P308Utility of a prominent R wave in lead V1 of a resting electrocardiogram for detecting significant cardiac pathology in an unselected population of young males

Background

Pre-participation electrocardiogram (ECG) screening is proposed as a means to detect cardiac pathology in asymptomatic individuals, and to select individuals for further cardiac investigation. Isolated ECG finding of Right Ventricular Hypertrophy (RVH) does not require further investigation based on the recent 2017 International Criteria. However, a prominent R wave in V1 has been described in cardiac abnormalities such as Wolff-Parkinson-White syndrome, hypertrophic cardiomyopathy, cardiomyopathy in Duchenne muscular dystrophy, arrhythmogenic right ventricular cardiomyopathy (ARVC), atrial septal defect and pulmonary hypertension.

Purpose

We sought to examine the utility of a prominent R wave in V1 as a screening criterion in an asymptomatic young male population of predominantly non-athletes, to detect significant structural cardiac pathology.

Methods

As part of the Singapore Armed Forces Electrocardiographic and Echocardiographic (SAFE) Protocol Study, pre-military enlistment screening ECG data was collected from 144,346 males between the ages of 16 to 22 from November 2009 to December 2014. Patients with ECGs with a prominent R wave, defined as an R wave ≥0.5mV in lead V1 with an R/S ratio of ≥1, were sent to a tertiary medical facility for a detailed transthoracic echocardiogram and subsequent cardiologist review. Any cardiac pathology identified was deemed significant if it led to the patient being excluded from participation in vigorous physical activity.

Results

1,144 patients with an isolated prominent R wave in V1 were studied. The mean age was 18.2±1.09 years and 81% were of Chinese ethnicity. None of the patients had echocardiographic evidence of RVH, 5 patients had a dilated right ventricle and 3 individuals had an elevated pulmonary artery systolic pressure. 11 patients (0.96%) had significant structural heart disease known to be associated with a prominent R wave in V1 that excluded them from participation in physical activity. These included large atrial septal defects (n=8), pulmonary stenosis (n=1), total anomalous pulmonary venous return (n=1) and hypertrophic cardiomyopathy (n=1). The test has a sensitivity of 21.6%, specificity of 93.4%, positive predictive value of 0.96% and negative predictive value of 99.8%,

Performance As Screening Criteria Number of Patients With Cardiac Pathology In Those Tested Positive Number of Patients With Cardiac Pathology In Those Tested Negative Positive Predictive Value (%) Negative Predictive Value (%) Sensitivity (%) Specificity (%) 11 40 0.96 99.8 21.6 93.4

Significant Cardiac Pathology Identified

Conclusion

A prominent R in V1 is not associated with echocardiographic RVH, or ARVC even in a large predominantly non-athletic male population. However, 0.96% of such patients would have other significant cardiac pathologies such as a large atrial septal defect.

Development and calibration of a novel positive mindset item bank to measure health-related quality of life (HRQoL) in Singapore

BACKGROUND

Positive mindset (PM) is an important domain of health-related quality of life in Singapore, a multi-ethnic urban city state in Southeast Asia. We therefore developed and calibrated a novel item bank to measure and improve PM.

METHODS

We developed an initial candidate pool of 48 items from focus groups, in-depth interviews and existing instruments locally developed and validated for use in Singapore. We administered all items in English to a multi-stage sample stratified for age and gender, of subjects with and without medical conditions recruited from the community and a hospital, and calibrated their responses using Samejima's Graded Response Model. We evaluated a final 36-item bank with respect to Item Response Theory (IRT) model assumptions, model fit, differential item functioning (DIF), concurrent and known-groups validity.

RESULTS

Among 493 participants (49.3% male, 41.6% above 50 years old, 33% Chinese, Malay and Indian), bifactor model analyses supported unidimensionality: explained common variance of the general factor was 0.86 and omega hierarchical was 0.97. Local independence was deemed acceptable: the average absolute residual correlations were <0.06 and 3.3% of the total item-pair residuals were flagged for local dependence. The overall model fit was adequate and provided good coverage of the PM construct (theta range: -3.6 to +2.4). Five items exhibited DIF with respect to ethnicity and gender, but were retained without modification of scores because they measured important aspects of PM. Scores correlated in the hypothesized direction with a self-reported measure of global health (Spearman's rho = -0.28, p<0.001) and discriminated between groups of participants with and without a self-reported diagnosis of a mood disorder (p = 0.007) adjusting for age, gender, ethnicity, education and marital status.

CONCLUSION

The 36-item PM item bank demonstrated satisfactory psychometric properties for the English-speaking Singaporean population. IRT model assumptions were sufficiently met and scores showed concurrent and known-groups validity. Future studies to evaluate the validity of PM scores when items are administered adaptively are needed.

Development and calibration of a novel social relationship item bank to measure health-related quality of life (HRQoL) in Singapore

BACKGROUND

Social relationships (SR) is an important domain of health-related quality of life. We developed and calibrated a novel item bank to measure SR in Singapore, a multi-ethnic city in Southeast Asia.

METHODS

We developed an initial candidate pool of 51 items from focus groups, individual in-depth interviews and existing instruments that had been developed and/or validated for use in Singapore. We administered all items in English to a multi-stage sample of subjects, stratified for age and gender, with and without medical conditions, recruited from community and hospital settings. We calibrated their responses using Samejima's Graded Response Model (SGRM). We evaluated a final 30-item bank with respect to Item Response Theory (IRT) model assumptions, model fit, differential item functioning (DIF), and concurrent and known-groups validity.

RESULTS

Among 503 participants (47.7% male, 41.4% above 50 years old, 34.0% Chinese, 33.6% Malay and 32.4% Indian), bi-factor model analyses supported essential unidimensionality: explained common variance of the general factor was 0.805 and omega hierarchical was 0.98. Local independence was deemed acceptable: the average absolute residual correlations were < 0.06 and 1.8% of the total item-pair residuals were flagged for local dependence. The overall SGRM model fit was adequate (p = 0.146). Five items exhibited DIF with respect to age, ethnicity and education, but were retained without modification of scores because they measured important aspects of SR. The SR scores correlated in the hypothesized direction with a self-reported measure of global health (Spearman's rho = - 0.28, p < 0.001).

CONCLUSION

The 30-item SR item bank has shown acceptable psychometric properties. Future studies to evaluate the validity of SR scores when items are administered adaptively are needed.

Comparative analysis of recurrent events after presentation with an index myocardial infarction or ischaemic stroke

Aims

Acute myocardial infarction (AMI) and stroke are important causes of mortality and morbidity. Our aims are to determine the comparative epidemiology of AMI and ischaemic stroke; and examine the differences in cardiovascular outcomes or mortality occurring after an AMI or stroke.

Methods and results

The Singapore National Registry of Diseases Office collects countrywide data on AMI, stroke, and mortality. Index events of AMI and ischaemic stroke between 2007 and 2012 were identified. Patients were then matched for occurrences of subsequent AMI, stroke, or death within 1-year of the index event. There were 33 222 patients with first-ever AMI and 20 982 with first-ever stroke. AMI patients were significantly more likely to be men (66.3% vs. 56.9%), non-Chinese (32.1% vs. 24.1%), and smokers (43.1% vs. 38.6%), but less likely to have hypertension (65.6% vs. 79%) and hyperlipidaemia (61.1% vs. 65.5%), compared with stroke patients. In total 6.8% of the AMI patients had recurrent AMI, whereas 4.8% of the stroke patients had recurrent stroke within 1 year; 31.7% of the AMI patients died, whereas 17.1% of the ischaemic stroke patients died within 1 year. Older age, Malay ethnicity, and diabetes mellitus were statistically significant risk factors for all-cause mortality and for the composite endpoint of AMI, stroke, and all-cause mortality, at 1 year.

Conclusions

Risk profiles of patients with AMI and stroke are significantly different. Patients suffer recurrent events in vascular territories similar to the index event. Age and diabetes mellitus are significant predictors of recurrent vascular events and mortality.

A multicenter prospective randomized study comparing the efficacy of escalating higher biphasic versus low biphasic energy defibrillations in patients presenting with cardiac arrest in the in-hospital environment

Background

Biphasic defibrillation has been practiced worldwide for >15 years. Yet, consensus does not exist on the best energy levels for optimal outcomes when used in patients with ventricular fibrillation (VF)/pulseless ventricular tachycardia (VT).

Methods

This prospective, randomized, controlled trial of 235 adult cardiac arrest patients with VF/VT was conducted in the emergency and cardiology departments. One group received low-energy (LE) shocks at 150–150–150 J and the other escalating higher-energy (HE) shocks at 200–300–360 J. If return of spontaneous circulation (ROSC) was not achieved by the third shock, LE patients crossed over to the HE arm and HE patients continued at 360 J. Primary end point was ROSC. Secondary end points were 24-hour, 7-day, and 30-day survival.

Results

Both groups were comparable for age, sex, cardiac risk factors, and duration of collapse and VF/VT. Of the 118 patients randomized to the LE group, 48 crossed over to the HE protocol, 24 for persistent VF, and 24 for recurrent VF. First-shock termination rates for HE and LE patients were 66.67% and 64.41%, respectively (P=0.78, confidence interval: 0.65–1.89). First-shock ROSC rates were 25.64% and 29.66%, respectively (P=0.56, confidence interval: 0.46–1.45). The 24-hour, 7-day, and 30-day survival rates were 85.71%, 74.29%, and 62.86% for first-shock ROSC LE patients and 70.00%, 50.00%, and 46.67% for first-shock ROSC HE patients, respectively. Conversion rates for further shocks at 200 J and 300 J were low, but increased to 38.95% at 360 J.

Conclusion

First-shock termination and ROSC rates were not significantly different between LE and HE biphasic defibrillation for cardiac arrest patients. Patients responded best at 150/200 J and at 360 J energy levels. For patients with VF/pulseless VT, consideration is needed to escalate quickly to HE shocks at 360 J if not successfully defibrillated with 150 or 200 J initially.

Symptom-to-door delay among patients with ST-segment elevation myocardial infarction in Singapore

OBJECTIVES

Symptom-to-door time (S2D) is one of the important components of ischaemic time, which might affect the infarct size and outcomes of acute myocardial infarction. The aim of the present study was to identify patients' characteristics associated with delayed symptom-onset-to-arrival at EDs in ST-segment elevation myocardial infarction (STEMI) patients in Singapore.

METHODS

Retrospective data of STEMI patients presenting to the ED of all public hospitals with onsite primary percutaneous coronary intervention facilities between 2010 and 2012 were obtained from the Singapore Myocardial Infarction Registry. Based on the S2D of 120 min, characteristics of patients were compared between short S2D (≤120 min) and long S2D (>120 min). Multivariate logistic and linear regression analyses were performed.

RESULTS

Out of 3848 patients, 1682 patients had an S2D of ≤120 min, and 2166 had an S2D >120 min. In the multivariate analyses, older age, Malay ethnicity, diabetes mellitus, presenting symptoms of back and epigastric pain were independently associated with long S2D. Patients who utilised the emergency medical services, presented after office hours and with symptoms of chest pain, breathlessness, diaphoresis and past history of percutaneous transluminal coronary angioplasty/primary percutaneous coronary intervention, were independently associated with short S2D. Patients with long S2D had lower probability of receiving reperfusion treatment with delayed symptom-to-balloon and door-to-balloon time and higher probabilities of complications and mortality.

CONCLUSION

The present study shows that longer S2D was associated with older age, ethnicity, diabetes mellitus, delay in receiving early reperfusion treatment and poorer prognosis.

Simplified Models of Non-Invasive Fractional Flow Reserve Based on CT Images

Invasive fractional flow reserve (FFR) is the gold standard to assess the functional coronary stenosis. The non-invasive assessment of diameter stenosis (DS) using coronary computed tomography angiography (CTA) has high false positive rate in contrast to FFR. Combining CTA with computational fluid dynamics (CFD), recent studies have shown promising predictions of FFRCT for superior assessment of lesion severity over CTA alone. The CFD models tend to be computationally expensive, however, and require several hours for completing analysis. Here, we introduce simplified models to predict noninvasive FFR at substantially less computational time. In this retrospective pilot study, 21 patients received coronary CTA. Subsequently a total of 32 vessels underwent invasive FFR measurement. For each vessel, FFR based on steady-state and analytical models (FFRSS and FFRAM, respectively) were calculated non-invasively based on CTA and compared with FFR. The accuracy, sensitivity, specificity, positive predictive value and negative predictive value were 90.6% (87.5%), 80.0% (80.0%), 95.5% (90.9%), 88.9% (80.0%) and 91.3% (90.9%) respectively for FFRSS (and FFRAM) on a per-vessel basis, and were 75.0%, 50.0%, 86.4%, 62.5% and 79.2% respectively for DS. The area under the receiver operating characteristic curve (AUC) was 0.963, 0.954 and 0.741 for FFRSS, FFRAM and DS respectively, on a per-patient level. The results suggest that the CTA-derived FFRSS performed well in contrast to invasive FFR and they had better diagnostic performance than DS from CTA in the identification of functionally significant lesions. In contrast to FFRCT, FFRSS requires much less computational time.

Emergency Medical Services Utilization among Patients with ST-Segment Elevation Myocardial Infarction: Observations from the Singapore Myocardial Infarction Registry

OBJECTIVE

Early activation of emergency medical services (EMS), rapid transport, and treatment of patients experiencing ST-segment elevation myocardial infarction (STEMI) can improve outcomes. The Singapore Myocardial Infarction Registry (SMIR) is a nation-wide registry that collects data on STEMI. We aimed to determine the prevalence, predictors, and outcomes of EMS utilization among STEMI patients presenting to Emergency Departments (ED) in Singapore.

METHODS

We analyzed STEMI patients enrolled by SMIR from January 2010 to December 2012. We excluded patients who were transferred, developed STEMI in-hospital or suffered cardiac arrest out-of-hospital or in the ED. Primary outcome was process-of-care timings. Secondary outcomes included the occurrence of cardiac complications. Multivariate analysis was used to examine independent factors associated with EMS transport.

RESULTS

6412 patients were enrolled into the study; 4667 patients were eligible for analysis. 49.8% of patients utilized EMS transport. EMS transport was associated with higher rate of reperfusion therapy (74.3% vs. 65.1%, p < 0.01), shorter median symptom-to-door time (119 vs. 182 minutes, p < 0.01), door-to-balloon time (59 vs. 70 minutes, p < 0.01), and symptom-to-balloon time (185 vs. 233 minutes, p < 0.01). EMS transport had more patients with Killip Class 4 (7.5% vs 4.0%, p < 0.01) and was associated with greater presentation of heart failure, arrhythmias, and complete heart block. Independent predictors of EMS transport were age, syncope and Killip score; after-office-hour presentation was a negative predictor.

CONCLUSION

Less than half of STEMI patients utilized EMS and EMS patients had faster receipt of initial reperfusion therapies. Targeted public education to reduce time to treatment may improve the care of STEMI patients.

Hypereosinophilic syndrome with large intracardiac thrombus

As the nonspecific clinical presentation of hypereosinophilic syndrome (HES) may mimic many multisystemic diseases, it often presents as a diagnostic challenge. Herein, we report the case of a 60-year-old man who presented with progressive heart failure symptoms and eosinophilia. Despite extensive diagnostic evaluation, no underlying cause was found. Transthoracic echocardiography revealed a large left ventricular thrombus, which is suggestive of hypereosinophilic cardiac involvement. The patient was started on steroids and responded clinically and haematologically.

Impact of the joint association between sex, age and diabetes on long-term mortality after acute myocardial infarction

BACKGROUND

The role of sex, and its joint effect with age and diabetes mellitus, on mortality subsequent to surviving an acute myocardial infarction (AMI) beyond 30 days are unclear. The high prevalence of diabetes mellitus in an ethnically diverse Asian population motivates this study.

METHODS

The study population comprised of a nationwide cohort of Asian patients with AMI, hospitalized between 2000 to 2005, who survived the first 30 days post-admission and were followed prospectively until death or 12 years.

RESULTS

Among the 13,389 survivors, there were fewer women (25.5%) who were older than men (median 70 vs. 58 years) and a larger proportion had diabetes mellitus at admission (51.4% vs. 31.4%). During follow-up 4,707 deaths (women 13.2%; men 22.0%) occurred, with women experiencing higher mortality than men with an averaged hazard ratio (HR): 2.08; 95% confidence interval : 1.96-2.20. However the actual adverse outcome, although always greater, reduced over time with an estimated HR: 2.23 (2.04-2.45) at 30 days to HR: 1.75; (1.47-2.09) 12 years later. The difference in mortality also declined with increasing age: HR 1.80 (1.52-2.13) for those aged 22-59, 1.26 (1.11-1.42) for 60-69, 1.06 (0.96-1.17) and 0.96 (0.85-1.09) for those 70-79 and 80-101 years. Significant two-factor interactions were observed between sex, age and diabetes (P < 0.001). Diabetic women <60 years of age had greater mortality than diabetic men of the same age (adjusted HR: 1.44; 1.14-1.84; P = 0.003), while diabetic women and men ≥60 years of age had a less pronounced mortality difference (adjusted HR: 1.12; 0.99-1.26).

CONCLUSIONS

One in two women hospitalized for AMI in this Asian cohort had diabetes and the sex disparity in post-MI mortality was most pronounced among these who were <60 years of age. This underscores the need for better secondary prevention in this high-risk group.

Lifetime cost-effectiveness analysis of ticagrelor in patients with acute coronary syndromes based on the PLATO trial: a Singapore healthcare perspective

INTRODUCTION

Ticagrelor is a novel antiplatelet drug developed to reduce atherothrombosis. The PLATO trial compared ticagrelor and aspirin to clopidogrel and aspirin in patients with acute coronary syndromes (ACS). Ticagrelor was found to be superior in the primary composite endpoint of cardiovascular death, myocardial infarction or stroke, without increasing major bleeding events. The current study estimates the lifetime cost-effectiveness of ticagrelor relative to generic clopidogrel from a Singapore public healthcare perspective.

METHODS

This study used a two-part cost-effectiveness model. The first part was a 12-month decision tree (using PLATO trial data) to estimate the rates of major cardiovascular events, healthcare costs and health-related quality of life. The second part was a Markov model estimating lifetime quality-adjusted survival and costs conditional on events during the initial 12 months. Daily drug costs applied were SGD 1.05 (generic clopidogrel) and SGD 6.00 (ticagrelor). Cost per quality-adjusted life years (QALY) was estimated from a Singapore public healthcare perspective using life tables and short-term costs from Singapore, and long-term costs from South Korea. Deterministic and probabilistic sensitivity analyses were performed.

RESULTS

Ticagrelor was associated with a lifetime QALY gain of 0.13, primarily driven by lower mortality. The resulting incremental cost per QALY gained was SGD 10,136.00. Probabilistic sensitivity analysis indicated that ticagrelor had a > 99% probability of being cost-effective, given the lower recommended WHO willingness-to-pay threshold of one GDP/capita per QALY.

CONCLUSION

Based on PLATO trial data, one-year treatment with ticagrelor versus generic clopidogrel in patients with ACS, relative to WHO reference standards, is cost-effective from a Singapore public healthcare perspective.

Clinical features and outcome of emergency percutaneous intervention of left main coronary artery occlusion in acute myocardial infarction

INTRODUCTION

Acute myocardial infarction (AMI) due to left main coronary artery (LMCA) occlusion carries a grave prognosis. Large series reporting on the outcome of emergency revascularisation (percutaneous or surgical) of acute LMCA occlusion have been scarce. We seek to identify, in our local population, the clinical presentation and outcome of this group of patients.

METHODS

From January 2000 to December 2005, a total of 1,539 patients underwent primary percutaneous coronary angioplasty for AMI in our institution. 11 patients (0.8 percent) underwent percutaneous intervention to the LMCA. These patients became the subjects of our study. Data on demography, clinical features and outcome was collected from all in-hospital and clinical notes. One sub-investigator, who was blinded to the study outcome, assessed the angiographical features.

RESULTS

The overall inpatient mortality was 82 percent (9 out of 11). Nine out of 11 patients presented with cardiogenic shock. All patients presented with shock died during the hospital stay. All patients required intra-aortic balloon counter pulsation insertion. Of the two patients who survived till discharge, one had angioplasty followed by bypass surgery. The remaining one had angioplasty and stenting to the left main artery. Both survivors have been doing well without further major adverse cardiac event after an average of 64 months of follow-up.

CONCLUSION

Percutaneous revascularisation of acute LMCA occlusion is feasible and the best outcome is seen in stable patients. Prognosis is still poor in patients with unfavourable clinical features.

Effect of left ventricular shape alteration on contractility and function

We have investigated the effect of left ventricular (LV) shape on contractility and ejection function. In this study, a new contractility index is developed in terms of the wall stress (sigma*, normalized with respect to LV pressure) by means of an LV ellipsoidal model. Using cine-ventriculography data, the LV ellipsoidal model (LVEM) major (B) and minor axes (A) are derived for the entire cardiac cycle. Thereafter, a new contractility index (CONT1) is derived as dsigma*/dt, incorporating the LV ellipsoidal shape factor. Also, another contractility index (CONT2) was developed in terms of the generated sigma* at the start of ejection phase, and maximized with respect to B/Ashape parameter, to obtain the optimal value of B/Aover the physiological ranges of the ratio of myocardial volume and LV volume. The in vivovalue of B/Aat the start of ejection is compared with this optimal value, and the LV contractility is evaluated in terms of the proximity of the in vivo B/Ato the optimal B/A. The results indicate that a non-optimal less-ellipsoidal shape (or more spherical) is associated with decreased contractility (and poor systolic function) of the LV, associated with a failing heart.

Nuclear cardiology in Singapore: a review

Since its introduction in Singapore more than 10 years ago, nuclear cardiology has now become an integral part of comprehensive cardiac workup of patients with a variety of cardiac diseases. We trace its local development from the 1980s to its present-day role in cardiac evaluation, and into the potential future of genetic and molecular cardiology.

An evaluation of point-of-care instrument for monitoring anticoagulation level in adult cardiac patients

INTRODUCTION

Rapid point-of-care measurement of anticoagulation has become feasible with the advent of new portable devices and offers the potential for home monitoring. This study evaluates the accuracy and feasibility of such a point-of-care device, the ProTime analyser as compared with standard laboratory method (IL MCL2) for monitoring the International Normalised Ratio (INR) level in cardiac patients on oral anticoagulation therapy.

MATERIALS AND METHODS

Fifty patients were studied. The majority were male (86% versus 14%). Chinese accounted for 37(74%) whereas Malay and Indian, constituted 9(18%) and 4(8%) respectively. The mean age was 55 +/- 12 years. Prosthetic heart valve replacement (46%) and atrial fibrillation (38%) were among the main indications for anticoagulation. The mean dosage of warfarin was 3.0 +/- 1.5 mg (range 1.0 to 6.5 mg) and the INR results ranged from 0.83 to 4.69 (based on the hospital laboratory method). Fingerstick and venous blood samples were collected from every patient and subjected to analysis by ProTime and IL MCL2 analysers.

RESULTS

There was a good correlation of INRs between ProTime venous and IL MCL2 venous, ProTime fingerstick and IL MCL2 venous and ProTime venous and ProTime fingerstick samplings, with correlation coefficients (r) of 0.9248, 0.9403 and 0.9557, respectively. The Bland-Altman plot also showed a good correlation between the methods used without any systematic bias (limits of agreement ranged from -0.422 to +0.606 INR units on average).

CONCLUSION

This rapid point-of-care device appears to have an acceptable level of accuracy for measuring INR values in the recommended target ranges in adult cardiac patients on oral anticoagulation therapy.

Myocardial infarction in Singapore: a nationwide 10-year study of multiethnic differences in incidence and mortality

INTRODUCTION AND METHODS

Cardiovascular diseases have progressively increased in importance as a major contributor of morbidity and mortality in Asia. However, many countries in Asia do not have nationwide systematically-collected and standardised data on myocardial infarction (MI). To accurately document the extent of atherosclerotic coronary heart disease in Singapore, a nationwide myocardial infarct registry was established in the mid-1986. Possible myocardial infarct events were identified through daily national lists of cardiac enzymes, hospital discharge codes, mortuary records and the national death registry. Data obtained from clinical history, cardiac enzymes and 12-lead electrocardiogram Minnesota codes were entered into an algorithm based on the WHO MONICA study. Cases identified as "definite" MI were included in the decade's review for this study.

RESULTS

From 1988 to 1997, 13,048 myocardial infarct events were diagnosed with 3367 deaths. There was a 39.1% decline in mortality, with an average decline of 6.5% per year [95% confidence intervals (CI), -3.9% to -9.1%]. However, the decline in incidence was only 20.8% with an average decline of 2.4% per year (95% CI, -6.6% to -1.2%). The highest incidence and mortality rates for both genders were seen in the Indians, followed by the Malays and the Chinese.

CONCLUSION

Over 10 years, from 1988 to 1997, we documented a significant fall in mortality from MI in Singapore. There was a smaller decline in the incidence of infarction. Singapore implemented a National Healthy Lifestyle Programme in 1992 as a 10-year effort. The disparity in the incidence and mortality may suggest that a more dramatic and immediate impact has taken place in mortality through therapeutic programmes; primary preventive programmes would be more difficult to evaluate and have a more gradual impact. Only with continual accurate data collection through the whole country, over a much longer period, can the relative value of preventive and therapeutic programmes in coronary heart disease be assessed.