Ling Ling Sim

Recalibration of the Global Registry of Acute Coronary Events risk score in a multiethnic Asian population

BACKGROUND Acute myocardial infarction (AMI) is a leading cause of mortality in Asia. However, quantitative risk scores to predict mortality after AMI were developed without the participation of Asian countries. METHODS We evaluated the performance of the Global Registry of Acute Coronary Events (GRACE) in-hospital mortality risk score, directly and after recalibration, in a large Singaporean cohort representing 3 major Asian ethnicities. RESULTS The GRACE cohort included 11,389 patients, predominantly of European descent, hospitalized for AMI or unstable angina from 2002 to 2003. The Singapore cohort included 10,100 Chinese, 3,005 Malay, and 2,046 Indian patients hospitalized for AMI from 2002 to 2005.Using the original GRACE score, predicted in-hospital mortality was 2.4% (Chinese), 2.0% (Malay), and 1.6% (Indian). However, observed in-hospital mortality was much greater at 9.8% (Chinese), 7.6% (Malay), and 6.4% (Indian). The c statistic for Chinese, Malays, and Indians was 0.86, 0.86, and 0.84, respectively, and the Hosmer-Lemeshow statistic was 250, 56, and 41, respectively. Recalibration of the GRACE score, using the mean-centered constants derived from the Singapore cohort, did not change the c statistic but substantially improved the Hosmer-Lemeshow statistic to 90, 24, and 18, respectively. The recalibrated GRACE score predicted in-hospital mortality as follows: 7.7% (Chinese), 6.0% (Malay), and 5.2% (Indian). CONCLUSION In this large cohort of 3 major Asian ethnicities, the original GRACE score, derived from populations outside Asia, underestimated in-hospital mortality after AMI. Recalibration improved risk estimation substantially and may help adapt externally developed risk scores for local practice.

Myocardial contractile dysfunction associated with increased 3-month and 1-year mortality in hospitalized patients with heart failure and preserved ejection fraction

BACKGROUND There is a clinical need for a contractility index that reflects myocardial contractile dysfunction even when ejection fraction (EF) is preserved. We used novel relative load-independent global and regional contractility indices to compare left ventricular (LV) contractile function in three groups: heart failure (HF) with preserved ejection fraction (HFPEF), HF with reduced ejection fraction (HFREF) and normal subjects. Also, we determined the associations of these parameters with 3-month and 1-year mortality in HFPEF patients. METHODS 199 HFPEF patients [median age (IQR): 75 (67-80) years] and 327 HFREF patients [69 (59-76) years] were recruited following hospitalization for HF; 22 normal control subjects [65 (54-71) years] were recruited for comparison. All patients underwent standard two-dimensional Doppler and tissue Doppler echocardiography to characterize LV dimension, structure, global and regional contractile function. RESULTS The median (IQR) global LV contractility index, dσ*/dtmax was 4.30s(-1) (3.51-4.57s(-1)) in normal subjects but reduced in HFPEF [2.57 (2.08-3.64)] and HFREF patients [1.77 (1.34-2.30)]. Similarly, median (IQR) regional LV contractility index was 99% (88-104%) in normal subjects and reduced in HFPEF [81% (66-96%)] and HFREF [56% (41-71%)] patients. Multi-variable logistic regression analysis on HFPEF identified sc-mFS <76% as the most consistent predictor of both 3-month (OR=7.15, p<0.05) and 1-year (OR=2.57, p<0.05) mortality after adjusting for medical conditions and other echocardiographic measurements. CONCLUSION Patients with HFPEF exhibited decreased LV global and regional contractility. This population-based study demonstrated that depressed regional contractility index was associated with higher 3-month and 1-year mortality in HFPEF patients.

Predictors of two-year mortality in Asian patients with heart failure and preserved ejection fraction

INTRODUCTION Mortality in patients with heart failure and preserved ejection fraction (HFpEF) remains high. Data from Asia is lacking. We aim to study the impact of ethnicity and other predictors of mortality in patients admitted for HFpEF in a multi-ethnic Asian country. MATERIAL AND METHODS Consecutive patients admitted to two local institutions with heart failure and ejection fraction ≥50% on transthoracic echocardiogram from Jan 2008 to Dec 2009 were included. All patients were followed-up for 2 years. Overall mortality was obtained from the national registry of deaths in our country. RESULTS A total of 1960 patients with heart failure were included. 751 (38.3%) patients had HFpEF. Overall mortality at two years was 26.6% (n=200) compared to 37.1% (n=449) in patients with reduced ejection fraction (HR 0.618 (95% CI 0.508-0.753), p<0.001). Ethnicity did not predict mortality. On multivariable Cox regression analysis, significant predictors of two-year mortality in HFpEF patients were older age (HR 1.027 (1.011-1.044)), prior myocardial infarction (HR 1.577 (1.104-2.253)), prior stroke (HR 1.475 (1.055-2.061)), smoking (HR 1.467 (1.085-1.985)), higher creatinine levels (HR 1.002 (1.001-1.003)) and use of mineralocorticoid receptor antagonists (HR 1.884 (1.226-2.896)). Use of warfarin (HR 0.506 (0.304-0.842)) and statins (HR 0.585 (0.435-0.785)) were associated with significantly lower mortality. CONCLUSIONS In our Asian population presenting with HFpEF, two-year mortality was 26.6%. Ethnicity did not predict mortality. Older age, prior myocardial infarction, prior stroke, smoking, and higher creatinine levels were found to be significant predictors of mortality.

Predictors of mortality in acute heart failure: interaction between diabetes and impaired left ventricular ejection fraction.

The aim of this study was to test the hypothesis that diabetes modifies the risk of mortality in acute heart failure patients, especially in patients with impaired LVEF, and that impaired LVEF in turn modifies the risk of mortality in diabetic patients.

Long-term outcomes after coronary bare-metal-stent and drug-eluting-stent implantations: a 'real-world' comparison among patients with diabetes with diffuse small vessel coronary artery disease.

Background and aimDrug-eluting stents (DESs) have been reported to be more efficacious compared with bare-metal stents (BMSs) in reducing the need for target vessel revascularization (TVR). However, the long-term benefits for patients with diabetes with small vessel disease are less certain. We aim to determine the clinical outcome of patients with diabetes with diffuse small vessel coronary artery disease who undergo percutaneous coronary intervention. MethodsThis is a single-center prospective registry of all patients with diabetes with target lesions implanted with stents that were 2.25 mm or less in diameter and approximately 20 mm in total stent length between January 2002 and October 2008. Primary outcome was combined major adverse cardiovascular events: death, nonfatal myocardial infarction and TVR up to 5 years. Outcomes were adjusted for age, sex and cardiovascular risk factors. ResultsThere were 544 patients (63% males, mean age 62±10 years) with 1010 lesions that were followed up for a mean duration of 3±2 years. Two hundred and thirty-nine patients (439 lesions) received BMS whereas 305 (571 lesions) received DES. DES lesions were longer (mean length 23.3±6.96 vs. 17.8±5.02 mm, P<0.001) than BMS lesions. Procedural success was similar for BMS and DES patients (86.2 vs. 86.6%, P=0.90). DES patients had less TVR at 6 months [3.9 vs. 9.2%, odds ratio (OR): 4.90, 95% confidence interval (CI): 1.53–15.65, P=0.007], 1 year (1 vs. 3.8%, OR: 8.01, 95% CI: 1.25–51.10, P=0.028) and3 years (13.8 vs. 18.0%, OR: 5.50, 95% CI: 3.74–8.13, P=0.043). By 5 years, the primary outcome was lower in DES patients (21.6 vs. 28%, OR: 1.79, 95% CI: 1.14–2.80, P=0.011). Independent predictors of TVR at 6 months were above or equal to 59 years of age (OR: 0.95, 95% CI: 0.90–1.00, P=0.032) and use of glycoprotein-IIbIIIa inhibitors (OR: 0.02, 95% CI: 0.001–0.50, P=0.018). Stent length was not a significant predictor of TVR. ConclusionOur observational analysis suggests that DES seems to have short-term and mid-term advantages over BMS in reducing TVR and overall major adverse cardiovascular events. Percutaneous coronary intervention with DES may be considered as an option in these patients with limited revascularization options.

Impact Of Sex On Clinical Characteristics And In-Hospital Outcomes In A Multi-Ethnic Southeast Asian Population Of Patients Hospitalized For Acute Heart Failure

Objectives:To study sex differences in clinical characteristics and outcomes among multi-ethnic Southeast Asian patients with hospitalized heart failure (HHF).Background:HHF is an important public health problem affecting man and women globally. Reports from Western populations suggest striking sex differences in risk factors and outcomes in HHF. However, this has not been studied in a multi-ethnic Asian population.Methods:Using the population-based resources of the Singapore Cardiac Data Bank, we studied 5,703 consecutive cases of HHF admitted across hospitals in the Southeast Asian nation of Singapore from 1st January, 2008 through 31st December, 2009.Results:Women accounted for 46% of total admissions and were characterized by older age (73 vs. 67 years; p<0.001), higher prevalence of hypertension (78.6 vs. 72.1%; p<0.001) or atrial fibrillation (22.2 vs. 18.1%; p<0.001), and lower prevalence of coronary artery disease (33.8 vs. 41.0%; p<0.001) or prior myocardial infarction (14.9 vs. 19.8%; p<0.001). Women were more likely than men to have HHF with preserved ejection fraction (42.5% versus 20.8%, p < 0.001). Women were less likely than men to receive evidencebased therapies at discharge, both in the overall group and in the sub-group with reduced ejection fraction. Women had longer lengths of stay (5.6 vs. 5.1 days; p<0.001) but similar in-hospital mortality and one-year rehospitalization rates compared to men. Independent predictors of mortality or rehospitalization in both men and women included prior myocardial infarction and reduced ejection fraction. Among women alone, additional independent predictors were renal impairment, atrial fibrillation, and diabetes. Prescription of beta-blockers and ACE-inhibitors at discharge was associated with better outcomes.Conclusion:Among multi-ethnic Asian patients with HHF, there are important sex differences in clinical characteristics and prognostic factors. These data may inform sex-specific strategies to improve outcomes of HHF in Southeast Asians.

Renal function and anaemia in acute myocardial infarction

BACKGROUND Impaired renal function and anaemia are common among patients with acute myocardial infarction (AMI). While both conditions are known independent risk factors for increased mortality, their interaction as risk factors for increased mortality in AMI is unclear. METHODS We studied 5395 subjects hospitalized for AMI between January 2000 and December 2005. An estimated glomerular filtration rate (GFR) <60 mL/min/1.73 m(2) was defined as impaired GFR and GFR ≥ 60 mL/min/1.73 m(2) was defined as preserved GFR. Anaemia was defined as <13 g/dL (males) and <12 g/dL (females). The odds ratio (OR) for one-year mortality and its 95% confidence interval (CI) were calculated by logistic regression. RESULTS We identified 758 (14%) patients with impaired GFR and anaemia, 1105 (20.5%) patients with impaired GFR without anaemia, 465 (8.6%) patients with preserved GFR and anaemia, and 3012 (55.8%) patients with preserved GFR without anaemia; one-year mortality rates were 56.5%, 41.8%, 31.8% and 10.3% respectively in these 4 groups. Among patients with impaired GFR, anaemia was associated with an adjusted OR of 1.47 (95% CI=1.17-1.85) for one-year mortality, while among patients with preserved GFR, anaemia was associated with a higher adjusted OR of 2.07 (95% CI=1.54-2.76) for one-year mortality, interaction P<0.001. CONCLUSION The combination of impaired GFR and anaemia confers greater than five-fold increased risk of mortality after AMI. The differential effect of anaemia among patients with impaired and preserved GFR on mortality suggests that in patients with preserved GFR anaemia confers a greater relative hazard than in patients with impaired renal function.

Comparing the use of cobalt chromium stents to stainless steel stents in primary percutaneous coronary intervention for acute myocardial infarction: A prospective registry

Objectives: To determine clinical outcome and rates of target vessel revascularization (TVR) in patients undergoing primary percutaneous coronary intervention (PCI) for STEMI who were treated with cobalt-chromium stents compared to stainless steel bare metal stents (BMS). Background: The newer generation cobalt chromium stents were reported to achieve lower rates of TVR compared with conventional BMS. Methods: Consecutive STEMI cases admitted within 12 h of symptom onset and undergoing primary angioplasty and bare metal stent implantation 1 January 2002 and 31 December 2008 were identified. Primary outcomes were rates of clinically-driven TVR at six months as well as occurrence of major adverse cardiovascular events (MACE) either of all-cause death, repeat myocardial infarction or TVR at six months. Results: 1030 cases with 1175 lesions (84% males) and median age of 58 years underwent primary PCI for STEMI in our registry. Overall procedural success rate was 98%. Stainless steel stents were inserted in 65% of the culprit lesions (stainless steel, n = 766 versus cobalt chromium, n = 264). Primary outcomes of TVR (3.5% in the stainless steel group and 3.4% in the cobalt chromium group, P = 0.93) and MACE (8.4% in the stainless steel group and 5.3% in the cobalt chromium group, P = 0.11) after six months were no different between the two groups. However, there were more deaths at 30 days in the stainless steel group compared to the cobalt chromium group (3.5% versus 0.4%, HR 4.04 (1.03–3.88), P = 0.04). Conclusion: Both cobalt-chromium and stainless steel coronary stents were associated with similar and low risk of clinically-driven TVR.

Influence of Ethnicity, Age, and Time on Sex Disparities in Long‐Term Cause‐Specific Mortality After Acute Myocardial Infarction

Background We examined the influence of sex, ethnicity, and time on competing cardiovascular and noncardiovascular causes of death following acute myocardial infarction in a multiethnic Asian cohort. Methods and Results For 12 years, we followed a prospective nationwide cohort of 15 151 patients (aged 22–101 years, median age 63 years; 72.3% male; 66.7% Chinese, 19.8% Malay, 13.5% Indian) who were hospitalized for acute myocardial infarction between 2000 and 2005. There were 6463 deaths (4534 cardiovascular, 1929 noncardiovascular). Compared with men, women had a higher risk of cardiovascular death (age‐adjusted hazard ratio [HR] 1.3, 95% CI 1.2–1.4) but a similar risk of noncardiovascular death (HR 0.9, 95% CI 0.8–1.0). Sex differences in cardiovascular death varied by ethnicity, age, and time. Compared with Chinese women, Malay women had the greatest increased hazard of cardiovascular death (HR 1.4, 95% CI 1.2–1.6) and a marked imbalance in death due to heart failure or cardiomyopathy (HR 3.4 [95% CI 1.9–6.0] versus HR 1.5 [95% CI 0.6–3.6] for Indian women). Compared with same‐age Malay men, Malay women aged 22 to 49 years had a 2.5‐fold (95% CI 1.6–3.8) increased hazard of cardiovascular death. Sex disparities in cardiovascular death tapered over time, least among Chinese patients and most among Indian patients; the HR comparing cardiovascular death of Indian women and men decreased from 1.9 (95% CI 1.5–2.4) at 30 days to 0.9 (95% CI 0.5–1.6) at 10 years. Conclusion Age, ethnicity, and time strongly influence the association between sex and specific cardiovascular causes of mortality, suggesting that health care policy to reduce sex disparities in acute myocardial infarction outcomes must consider the complex interplay of these 3 major modifying factors.

IMPACT OF SEX AND ITS INTERACTION WITH AGE AND DIABETES ON LONG-TERM SURVIVAL AFTER MYOCARDIAL INFARCTION IN AN ASIAN COHORT OF 13,389 PATIENTS

methods: We analyzed retrospectively all patients hospitalized for MI under the nationwide universal healthcare system in Singapore. A total of 13,389 patients (9,969 men and 3,420 women) were alive at 30 days after the index MI hospitalization during January 2000 to December 2005. All-cause death occurring up to 1st March 2012 was ascertained through linkage with the Singapore National Registry of Birth and Deaths. The hazard ratio (HR) for death and its 95% confidence interval (CI) were calculated by Cox regression.