Impact of time of onset of symptom of ST-segment elevation myocardial infarction on 1-year rehospitalization for heart failure and mortality.

Circadian patterns in ST-segment elevation myocardial infarction (STEMI) patients have been previously reported, but little is known about the impact of time dependence of symptom onset on long-term prognosis. Our study population consisted of 11,731 STEMI patients treated by primary percutaneous coronary intervention (PPCI), enrolled in the Singapore Myocardial Infarction Registry (SMIR). Analysis of STEMI incidence trends over the 24-hour period showed the highest rate of symptom onset in the morning, with the peak incidence at 09:00 am. Patients with symptom onset in between 00:00 am-5:59 am showed the highest prevalence of diabetes (P = .010) and anterior STEMI (P < .001) and had the longest ischemic time (P < .001). After adjusting for confounders, we found an association between time of symptom onset of STEMI and rehospitalization for heart failure (HF) at 1 year, with symptom onset between 06:00 pm-11:59 pm and 00:00 am-05:59 am having an estimated 30% to 50% higher risk of rehospitalization for HF at 1 year. Moreover, symptom onset remained a predictor of worse prognosis only in the subgroup of patients with symptoms lasting longer than 120 minutes. The results of this study demonstrate for the first time that rehospitalization for HF in STEMI patients treated with PPCI has a dependence on the time of onset of symptoms, with prolonged ischemia time playing a pivotal role. This may be an additional risk factor to identify those who warrant closer monitoring and more rigorous optimization of their treatment at follow-up, to improve their outcomes.

A Population-wide study of electrocardiographic (ECG) norms and the effect of demographic and anthropometric factors on selected ECG characteristics in young, Southeast Asian males-results from the Singapore Armed Forces ECG (SAFE) study.

BACKGROUND: Routine use of pre-participation electrocardiograms (ECGs) has been used by the Singapore Armed Forces, targeting early detection of significant cardiac diseases. We aim to describe the impact of demographic and anthropometric factors on ECG variables and establish a set of electrocardiographic reference ranges specific to a young male multiethnic Southeast Asian cohort. METHODS AND RESULTS: Between November 1, 2009, and December 31, 2014, 144,346 young male conscripts underwent pre-participation screening that included a 12-lead ECG, demographic and anthropometric measurements. The Chinese population had the longest PR interval (146.7 ± 19.7 vs. 145.21 ± 19.2 in Malays vs. 141.2 ± 18.8 ms in Indians), QRS duration (94.5 ± 9.8 vs. 92.6 ± 9.7 in Malays vs. 92.5 ± 9.4 ms in Indians) and QTcB interval (408.3 ± 21.3 vs. 403.5 ± 21.6 in Malays vs. 401.2 ± 21.4 ms in Indians) (all p < 0.001). Body mass index (BMI) >25 kg/m2 and body fat >25% were independently associated with lower prevalence of increased QRS voltage on ECG. Systolic blood pressure of >140 mmHg or diastolic blood pressure of >90 mmHg independently increased the prevalence of increased QRS voltage on ECG. CONCLUSIONS: Electrocardiographic parameters vary across different ethnicities and in comparison with international norms. In our population, diagnosis of increased QRS voltage by ECG is less prevalent with obesity and increased body fat. Further analysis of gold standard measurements for the diagnosis of LVH in our population is ongoing, to improve the accuracy of the ECG screening process.

Differential risk reclassification improvement by exercise testing and myocardial perfusion imaging in patients with suspected and known coronary artery disease.

OBJECTIVE: The objective of this study is to compare the incremental prognostic and net risk reclassification value of exercise testing alone vs exercise myocardial perfusion imaging (MPI) for estimating the risk of death in patients with suspected and known coronary artery disease (CAD). METHODS: 6702 patients with suspected CAD and 2008 with known CAD had treadmill exercise MPI and were followed for 2.5 ± 0.9 years for the occurrence of all-cause death. The estimation of risk of death and net reclassification improvement (NRI) were examined in three models. Model 1: clinical variables; Model 2: model 1+Duke Treadmill Score; and Model 3: model 2+ MPI variables. Risk estimates were categorized as <1%, 1-3%, and >3% risk of death per year. RESULTS: In patients with suspected CAD, the global Chi-square for predicting risk of death increased significantly for Model 2 compared to Model 1 (74.78 vs 63.86 to (P = .001). However, adding MPI variables in Model 3 did not further improve predictive value (Chi-square 79.38, P = .10). In patients with suspected CAD risk, reclassification improved significantly in Model 2 over Model 1 (NRI = 0.12, 95% CI 0.02 to 0.22, P = .019), but not in Model 3 (NRI = 0.0009, 95% CI -0.072 to 0.070; P = .98). In contrast, in patients with known CAD Model 2 did not yield significant improvements for predicting risk and risk reclassification compared to Model 1. However, global Chi-square of Model 3 was significantly higher than that of Model 2 (30.03 vs 6.56, P < .0001) with associated significant reclassification improvement (NRI = 0.26 95% CI 0.067 to 0.46. P = .0084). CONCLUSION: Risk reclassification by diagnostic testing is importantly influenced by baseline characteristics of patient cohorts. In patients with suspected CAD, NRI is predominately achieved by exercise variables, whereas in patients with known CAD, greatest NRI is obtained by MPI variables.

Single-photon emission computed tomography myocardial perfusion imaging-assessed stress perfusion defect severity is associated with mortality independent of ethnicity in an Asian population.

BACKGROUND: Ischemic heart disease is growing by epidemic proportions in Asia. Among patients in Western populations with similar myocardial perfusion imaging (MPI) ischemia severity, ethnicity is independently associated with mortality. We aimed to determine the differential prognostic value of MPI abnormality severity among three major Asian ethnic groups. METHODS: From 16,921 consecutive patients, we used summed stress score to define increasing abnormal scan severity groups (minimal, mild, moderate, and severe) among Chinese, Indian, and Malay patients. We determined mortality from the national death registry. Using multivariable Cox regression models, we examined the association between ethnicity and mortality. RESULTS: Chinese patients were older than Indians or Malays. Annual all-cause death rates increased with increasing abnormal scan severity in all three ethnicities. After adjustment, ethnicity was not associated with mortality. With Chinese as the reference group, adjusted hazard ratio and 95% CI for Malays and Indians were 1.29 (0.95-1.77) and 1.06 (0.74-1.50) in the minimally abnormal scan group, and 1.20 (0.75-1.91) and 0.82 (0.47-1.45) in the severely abnormal scan group, respectively. CONCLUSIONS: Mortality risk is related to the severity of scan abnormality and is independent of ethnicity in Asians. Our findings emphasize the continued utility of MPI in guiding risk stratification in Asia.

Evaluating the American Heart Association/American College of Cardiology Guideline-Recommended and Contemporary Pretest Probability Models in a Mixed Asian Cohort: The Contribution of Coronary Artery Calcium.

BACKGROUND: Most pretest probability (PTP) tools for obstructive coronary artery disease (CAD) were Western -developed. The most appropriate PTP models and the contribution of coronary artery calcium score (CACS) in Asian populations remain unknown. In a mixed Asian cohort, we compare 5 PTP models: local assessment of the heart (LAH), CAD Consortium (CAD2), risk factor-weighted clinical likelihood, the American Heart Association/American College of Cardiology and the European Society of Cardiology PTP and 3 extended versions of these models that incorporated CACS: LAH(CACS), CAD2(CACS), and the CACS-clinical likelihood. METHODS AND RESULTS: The study cohort included 771 patients referred for stable chest pain. Obstructive CAD prevalence was 27.5%. Calibration, area under the receiver-operating characteristic curves (AUC) and net reclassification index were evaluated. LAH clinical had the best calibration (χ2 5.8; P=0.12). For CACS models, LAH(CACS) showed least deviation between observed and expected cases (χ2 37.5; P<0.001). There was no difference in AUCs between the LAH clinical (AUC, 0.73 [95% CI, 0.69-0.77]), CAD2 clinical (AUC, 0.72 [95% CI, 0.68-0.76]), risk factor-weighted clinical likelihood (AUC, 0.73 [95% CI: 0.69-0.76) and European Society of Cardiology PTP (AUC, 0.71 [95% CI, 0.67-0.75]). CACS improved discrimination and reclassification of the LAH(CACS) (AUC, 0.88; net reclassification index, 0.46), CAD2(CACS) (AUC, 0.87; net reclassification index, 0.29) and CACS-CL (AUC, 0.87; net reclassification index, 0.25). CONCLUSIONS: In a mixed Asian cohort, Asian-derived LAH models had similar discriminatory performance but better calibration and risk categorization for clinically relevant PTP cutoffs. Incorporating CACS improved discrimination and reclassification. These results support the use of population-matched, CACS-inclusive PTP tools for the prediction of obstructive CAD.

Outcomes of Investigating T Wave Inversion With Echocardiography in an Unselected Young Male Preparticipation Cohort.

BACKGROUND Electrocardiography (ECG) may be performed as part of preparticipation sports screening. Recommendations on screening of athletes to identify individuals with previously unrecognized cardiac disease are robust; however, data guiding the preparticipation screening of unselected populations are scarce. T wave inversion (TWI) on ECG may suggest an undiagnosed cardiomyopathy. This study aims to describe the prevalence of abnormal TWI in an unselected young male cohort and the outcomes of an echocardiography-guided approach to investigating these individuals for structural heart diseases, focusing on the yield for cardiomyopathies. METHODS AND RESULTS Consecutive young male individuals undergoing a national preparticipation cardiac screening program for 39 months were studied. All underwent resting supine 12-lead ECG. Those manifesting abnormal TWI, defined as negatively deflected T waves of at least 0.1 mV amplitude in any 2 contiguous leads, underwent echocardiography. A total of 69 714 male individuals with a mean age of 17.9±1.1 years were studied. Of the individuals, 562 (0.8%) displayed abnormal TWI. This was most frequently observed in the anterior territory and least so in the lateral territory. A total of 12 individuals (2.1%) were diagnosed with a cardiomyopathy. Cardiomyopathy diagnoses were significantly associated with deeper maximum TWI depth and the presence of abnormal TWI in the lateral territory, but not with abnormal TWI in the anterior and inferior territories. No individual presenting with TWI restricted to solely leads V1 to V2, 2 inferior leads or both was diagnosed with a cardiomyopathy. CONCLUSIONS Cardiomyopathy diagnoses were more strongly associated with certain patterns of abnormal TWI. Our findings may support decisions to prioritize echocardiography in these individuals.

Correlation between clinical outcomes and appropriateness grading for referral to myocardial perfusion imaging for preoperative evaluation prior to non-cardiac surgery.

BACKGROUND: In a previous study, we have found that referral to myocardial perfusion imaging(MPI) for preoperative evaluation of patients before non-cardiac surgery was the most common cause of inappropriate referral based on AHA/ACC Appropriate Use Guidelines, though 40% of scans graded as inappropriate had abnormal MPI results. The aim of this study was to correlate appropriateness grading with (1) the outcome of MPI scans, and (2) the clinical outcome of patients after surgery, so as to determine if the predictive value of MPI was related to appropriateness grading. METHODS: All consecutive patients referred to the MPI laboratory of our center from March 2009 to July 2009 for preoperative risk stratification were prospectively studied. Patients' medical records and stress data were collected, and all imaging results were recorded. Based on appropriate use criteria (AUC), MPI studies were classified into appropriate, inappropriate, uncertain or unclassified. MPI studies were classified on the basis of their results into normal or abnormal scans. Primary clinical outcome measured was the occurrence of any major cardiac and cerebrovascular event during follow-up up to 90 days. RESULTS: There were 176 referrals for preoperative evaluation. 39.8% (n 5 70) of these referrals were graded as inappropriate. Based on AUC, referrals for MPI in intermediate- and high-risk groups with poor functional class were graded as appropriate, while referrals for MPI in low-risk and intermediate risk groups with normal functional class were graded as inappropriate referrals. The overall event rate was 6.25%. Cumulative death rate at 90 days was 1.7%, non-fatal MI 4%, and occurrence of stroke occurred in 0.6%. The primary outcome was higher in the intermediate group with poor functional class (13%) and high-risk group (64%) than the low-risk and intermediate risk groups with good functional class (4%). In the high-risk group, an abnormal MPI scan was associated with an extremely high event rate (50%) that was significantly greater than the event rate in patients with a normal MPI result (14%) (P 5 .01). Although 40% of preoperative low-risk and intermediate risk patients had an abnormal MPI result, their over all event rates were low (0 and 4%, respectively), with no difference in the rate of events between patients with normal and abnormal MPI scans in the inappropriate group. CONCLUSIONS: In conclusion, in correlating the relationship between appropriateness grading by AUC with the outcome of MPI scans and subsequent event rates, we found that MPI results predicted outcome in appropriately tested patients, but not in patients whose tests were classified as inappropriate, in whom event rates were low, regardless of the results of testing. Our findings support the AUC recommendations for the selective role of testing in preoperative risk stratification,which use the type of surgery and functional class to determine the appropriateness of referral.

Prevalence of electrocardiographic abnormalities in an unselected young male multi-ethnic South-East Asian population undergoing pre-participation cardiovascular screening: results of the Singapore Armed Forces Electrocardiogram and Echocardiogram screening protocol.

AIMS: Resting 12-lead electrocardiograms (ECGs) have been employed in the pre-participation evaluation of young asymptomatic subjects to detect pre-existing heart diseases. Although the incorporation of routine ECG in pre-participation screening remains controversial, there is increasing evidence that cardiomyopathies and ion channelopathies have ECG changes as the initial manifestation. The causes of sudden cardiac death in young people show significant geographical variation. We aim to determine the prevalence and spectrum of ECG abnormalities in a young male South-East Asian population. METHODS AND RESULTS: The Singapore Armed Forces Electrocardiogram and Echocardiogram (SAFE) protocol is an ECG-based pre-participation cardiac screening programme modelled after the Italian system. From October 2008 to May 2009, a total of 18 476 young male conscripts (mean age 19.5 years old, range 16-27) underwent mandatory pre-enlistment medical screening at a single medical facility. Subjects with abnormal ECG findings were classified into two groups: Group A had ECG changes that fulfilled a pre-specified checklist to screen for hypertrophic cardiomyopathy and were referred for transthoracic echocardiogram; Group B had other ECG abnormalities [such as Brugada pattern, Wolff-Parkinson-White (WPW) pattern, long QTc] and were referred for secondary screening at a tertiary institution. Of the 18 476 subjects screened, 7.0% (n= 1285) had ECG abnormalities. Of note, 19 (0.10%) had Brugada pattern, 25 (0.14%) had WPW pattern, and 31 (0.17%) had prolonged QT interval on ECG. The prevalence of ECG abnormalities was significantly higher in Chinese than in South Asians (7.2 vs. 5.7%, P= 0.003). CONCLUSION: The prevalence of ECG abnormalities in a young, South-East Asian male population was 7.0%. There were significant ethnic differences, with ECG abnormalities more prevalent in Chinese than in South Asians (7.2 vs. 5.7%, P= 0.003). The inclusion of universal ECG, in addition to history and physical examination, may increase the sensitivity of a cardiovascular screening programme. Knowledge of the spectrum and prevalence of ECG abnormalities and disease conditions would be pivotal in designing customized screening programmes.

Evaluation of the American College of Cardiology Foundation/American Society of Nuclear Cardiology appropriateness criteria for SPECT myocardial perfusion imaging in an Asian tertiary cardiac center.

BACKGROUND: Appropriate use criteria (AUC) for SPECT MPI have been published to address concern about the growth of cardiac imaging studies and the effective use of imaging, but there is no published data on its role outside the United States. METHODS: All consecutive patients referred to the MPI laboratory of our center from February 16 to June 19, 2009 were prospectively studied. Patients' medical records and stress data were collected and all imaging results were recorded. Based on AUC, MPI studies were classified into appropriate, inappropriate, uncertain, or unclassified. MPI studies were classified on the basis of their results into normal or abnormal scans. RESULTS: There were 1,623 patients (mean age 61 years ± 11, 61% males). Most common indications for SPECT were evaluation of ischemic equivalent for coronary artery disease (CAD), risk assessment post-revascularization, and preoperative evaluation for non-cardiac surgery. 10% of referrals were classified as inappropriate, 5% uncertain, and 3% unclassified. Women (48.4% vs 40.6% for men, P = .063) and asymptomatic patients (50.2% vs 14.3% for symptomatic, P < .001) had a higher proportion of inappropriate studies. The preoperative group had the highest proportion of inappropriate studies (59%). Appropriate referrals had a higher proportion of abnormal SPECT results than inappropriate referrals (40% vs 27%, OR 2.08, 95% CI 1.56-2.77, P < .001). CONCLUSIONS: The pattern of referrals for SPECT MPI in an Asian center appears to vary from published reports in the United States. Preoperative evaluation for low-risk surgery appears to be the most common source of inappropriate referrals in our institution. Inappropriate referrals have a higher proportion of normal studies, but 27% were still reported as abnormal.

Prevalence of hypertrophic cardiomyopathy on an electrocardiogram-based pre-participation screening programme in a young male South-East Asian population: results from the Singapore Armed Forces Electrocardiogram and Echocardiogram screening protocol.

AIMS: Hypertrophic cardiomyopathy is a leading cause of sudden cardiac death (SCD) in young people in the USA. Pre-participation screening for athletes might reduce the incidence of SCD. In Singapore, military service is compulsory for all young able-bodied male citizens. The Singapore Armed Forces Electrocardiogram and Echocardiogram (SAFE) pre-participation screening protocol based on the Italian programme was introduced. This study evaluates the prevalence of hypertrophic cardiomyopathy (HCM) in a young male South-East Asian population. METHODS AND RESULTS: From October 2008 to May 2009, all male military conscripts underwent pre-participation screening. For all conscripts whose electrocardiogram (ECG) findings fulfilled any of these pre-specified criteria (Group A), direct referral for a transthoracic echocardiogram was mandatory. Conscripts with ECG findings other than pre-specified criteria (e.g. T-wave inversions, repolarization abnormalities) were referred for secondary screening by cardiologists (Group B), which could include echocardiography. Out of 18 476 subjects screened during the study period, 988 (5.3%) subjects were fast tracked for echocardiogram (Group A). Of them, there were three (0.3%) cases with severe abnormalities; there was one case each of HCM, bicuspid aortic valve with significant aortic valve regurgitation, and atrial septal defect with right ventricular systolic dysfunction. The patient with HCM had left axis deviation on ECG. None of the 215 patients who underwent echocardiography following cardiology consult (Group B) had HCM. CONCLUSION: The prevalence of HCM in our young male population (mean age 19.5, range 16-27) using an ECG-based screening protocol was 0.005%; this appeared lower than published data from other geographical cohorts. Possible explanations include a later age of phenotypic manifestation in our population, limitations of the ECG criteria for screening, or a truly lower prevalence of HCM. More population-based longitudinal studies would be needed to ascertain the true prevalence of HCM in our South-East Asian population.

Percutaneous coronary intervention in Asians--are there differences in clinical outcome?

BACKGROUND: Ethnic differences in clinical outcome after percutaneous coronary intervention (PCI) have been reported. Data within different Asian subpopulations is scarce. We aim to explore the differences in clinical profile and outcome between Chinese, Malay and Indian Asian patients who undergo PCI for coronary artery disease (CAD). METHODS: A prospective registry of consecutive patients undergoing PCI from January 2002 to December 2007 at a tertiary care center was analyzed. Primary endpoint was major adverse cardiovascular events (MACE) of myocardial infarction (MI), repeat revascularization and all-cause death at six months. RESULTS: 7889 patients underwent PCI; 7544 (96%) patients completed follow-up and were included in the analysis (79% males with mean age of 59 years ± 11). There were 5130 (68%) Chinese, 1056 (14%) Malays and 1001 (13.3%) Indian patients. The remaining 357 (4.7%) patients from other minority ethnic groups were excluded from the analysis. The primary end-point occurred in 684 (9.1%) patients at six months. Indians had the highest rates of six month MACE compared to Chinese and Malays (Indians 12% vs. Chinese 8.2% vs. Malays 10.7%; OR 1.55 95%CI 1.24-1.93, p < 0.001). This was contributed by increased rates of MI (Indians 1.9% vs. Chinese 0.9% vs. Malays 1.3%; OR 4.49 95%CI 1.91-10.56 p = 0.001), repeat revascularization (Indians 6.5% vs. Chinese 4.1% vs. Malays 5.1%; OR 1.64 95%CI 1.22-2.21 p = 0.0012) and death (Indians 11.4% vs. Chinese 7.6% vs. Malays 9.9%; OR 1.65 95%CI 1.23-2.20 p = 0.001) amongst Indian patients. CONCLUSION: These data indicate that ethnic variations in clinical outcome exist following PCI. In particular, Indian patients have higher six month event rates compared to Chinese and Malays. Future studies are warranted to elucidate the underlying mechanisms behind these variations.

Independent Predictors of Cardiac Mortality and Hospitalization for Heart Failure in a Multi-Ethnic Asian ST-segment Elevation Myocardial Infarction Population Treated by Primary Percutaneous Coronary Intervention.

We aimed to identify independent predictors of cardiac mortality and hospitalization for heart failure (HHF) from a real-world, multi-ethnic Asian registry [the Singapore Myocardial Infarction Registry] of ST-segment elevation myocardial infarction (STEMI) patients treated by primary percutaneous coronary intervention. 11,546 eligible STEMI patients between 2008 and 2015 were identified. In-hospital, 30-day and 1-year cardiac mortality and 1-year HHF rates were 6.4%, 6.8%, 8.3% and 5.2%, respectively. From the derivation cohort (70% of patients), age, Killip class and cardiac arrest, creatinine, hemoglobin and troponin on admission and left ventricular ejection fraction (LVEF) during hospitalization were predictors of in-hospital, 30-day and 1-year cardiac mortality. Previous ischemic heart disease (IHD) was a predictor of in-hospital and 30-day cardiac mortality only, whereas diabetes was a predictor of 1-year cardiac mortality only. Age, previous IHD and diabetes, Killip class, creatinine, hemoglobin and troponin on admission, symptom-to-balloon-time and LVEF were predictors of 1-year HHF. The c-statistics were 0.921, 0.901, 0.881, 0.869, respectively. Applying these models to the validation cohort (30% of patients) showed good fit and discrimination (c-statistic 0.922, 0.913, 0.903 and 0.855 respectively; misclassification rate 14.0%, 14.7%, 16.2% and 24.0% respectively). These predictors could be incorporated into specific risk scores to stratify reperfused STEMI patients by their risk level for targeted intervention.

Sex Differences in 1-Year Rehospitalization for Heart Failure and Myocardial Infarction After Primary Percutaneous Coronary Intervention.

It is unclear whether universal access to primary percutaneous coronary intervention (pPCI) may reduce sex differences in 1-year rehospitalization for heart failure (HF) and myocardial infarction (MI) after ST-elevation myocardial infarction (STEMI). We studied 7,597 consecutive STEMI patients (13.8% women, n = 1,045) who underwent pPCI from January 2007 to December 2013. Cox regression models adjusted for competing risk from death were used to assess sex differences in rehospitalization for HF and MI within 1 year from discharge. Compared with men, women were older (median age 67.6 vs 56.0 years, p < 0.001) with higher prevalence of co-morbidities and multivessel disease. Women had longer median door-to-balloon time (76 vs 66 minutes, p < 0.001) and were less likely to receive drug-eluting stents (19.5% vs 24.1%, p = 0.001). Of the medications prescribed at discharge, fewer women received aspirin (95.8% vs 97.6%, p = 0.002) and P2Y12 antagonists (97.6% vs 98.5%, p = 0.039), but there were no significant sex differences in other discharge medications. After adjusting for differences in baseline characteristics and treatment, sex differences in risk of rehospitalization for HF attenuated (hazard ratio [HR] 1.05, 95% confidence interval [CI] 0.79 to 1.40), but persisted for MI (HR 1.68, 95% CI 1.22 to 2.33), with greater disparity in patients aged ≥60 years (HR 1.83, 95% CI 1.18 to 2.85) than those aged <60 years (HR 1.45, 95% CI 0.84 to 2.50). In conclusion, in a setting of universal access to pPCI, the adjusted risk of 1-year rehospitalization for HF was similar in both sexes, but women had significantly higher adjusted risk of 1-year rehospitalization for MI, especially older women.

Platelet inhibition to target reperfusion injury trial: Rationale and study design.

BACKGROUND: In ST-segment elevation myocardial infarction (STEMI) patients treated with primary percutaneous coronary intervention (PPCI), current oral P2Y12 platelet inhibitors do not provide maximal platelet inhibition at the time of reperfusion. Furthermore, administration of cangrelor prior to reperfusion has been shown in pre-clinical studies to reduce myocardial infarct (MI) size. Therefore, we hypothesize that cangrelor administered prior to reperfusion in STEMI patients will reduce the incidence of microvascular obstruction (MVO) and limit MI size in STEMI patients treated with PPCI. METHODS: The platelet inhibition to target reperfusion injury (PITRI) trial, is a phase 2A, multi-center, double-blinded, randomized controlled trial, in which 210 STEMI patients will be randomized to receive either an intravenous (IV) bolus of cangrelor (30 µg/kg) followed by a 120-minute infusion (4 µg/kg/min) or matching saline placebo, initiated prior to reperfusion (NCT03102723). RESULTS: The study started in October 2017 and the anticipated end date would be July 2020. The primary end-point will be MI size quantified by cardiovascular magnetic resonance (CMR) on day 3 post-PPCI. Secondary endpoints will include markers of reperfusion, incidence of MVO, MI size, and adverse left ventricular remodeling at 6 months, and major adverse cardiac and cerebrovascular events. SUMMARY: The aim of the PITRI trial is to assess whether cangrelor administered prior to reperfusion would reduce acute MI size and MVO, as assessed by CMR.

Improving access to outpatient cardiac care at the national heart centre--a partnership between specialists and primary care.

Ensuring timely access to specialist care is an important indicator of the quality of a health service. Demand for cardiology outpatient appointments has grown considerably in the last decade, leading to increased waiting time for cardiology appointments at public hospitals. This paper examines the effectiveness of past and ongoing strategies initiated by the National Heart Centre, many of which were in collaboration with SingHealth Polyclinics, documents the lessons learnt, and provides a framework for approaching this problem. Instead of a simplistic approach where institutions react to long waiting times by growing capacity to meet demand, this paper emphasises the need to focus on the final intended outcome (timely diagnosis and treatment) rather than on a single performance indicator, such as waiting time. A broad systems approach at the national level is advocated, rather than piecemeal, uncoordinated actions by individual hospitals.

Pattern and outcome of subsidised referrals to cardiology specialist outpatient clinics.

INTRODUCTION: Increasing demand for public healthcare and access to specialist care has become a major concern. Characterising the referral pattern to a national centre's cardiology specialist outpatient clinics (SOCs) and the diagnostic outcomes may be useful in formulating referral guidelines to contain rising demand. MATERIALS AND METHODS: A prospective observational followup study was conducted of all consecutive new patient referrals to the cardiology SOCs of the National Heart Centre over a 1-month period. The records of these 1224 patients were reviewed following their first visit and again after 3 months of evaluation and investigation. Patients' demographics, referral sources, indications of referral, risk factors, provisional and final diagnoses were collected. Referrals from the top 2 volume sources (government polyclinics and hospital Emergency Department) accounted for 600 referrals. These subsidised referrals formed the study group for analysis. RESULTS: The mean age of referred patients was 56 +/- 15.2 years, with equal proportion of males and females. Most patients had known cardiac risk factors of hypertension (53.2%) and hyperlipidaemia (42.3%). Only 23% of referrals had significant cardiac abnormalities. Referrals for typical chest pain derived the highest yield whereas referrals for atypical chest pain, non-cardiac chest pain derived the lowest yield. Referrals for asymptomatic electrocardiogram (ECG) changes (except for atrial flutter/fibrillation) did not yield cardiac abnormalities. Multivariate analysis of chest pain referrals showed typical chest pain and hyperlipidaemia to be statistically significant predictors for coronary artery disease. CONCLUSION: Referrals to cardiology outpatient specialist clinics should be based on the presence of patient symptoms, particularly that of typical chest pain. In asymptomatic patients, routine ECG screening did not appear to yield significant cardiac abnormalities.

Improving door-to-balloon times in primary percutaneous coronary intervention for acute ST-elevation myocardial infarction: the value of an audit-driven quality initiative.

INTRODUCTION: The study was designed to reduce door-to-balloon times in primary percutaneous coronary intervention for patients presenting to the Emergency Department with acute ST-elevation myocardial infarction, using an audit as a quality initiative. MATERIALS AND METHODS: A multidisciplinary work group performed a pilot study over 3 months, then implemented various process and work-flow strategies to improve overall door-to-balloon times. RESULTS AND CONCLUSION: We developed a guideline-based, institution-specific written protocol for triaging and managing patients who present to the Emergency Department with symptoms suggestive of STEMI, resulting in shortened median door-to-balloon times from 130.5 to 109.5 minutes (P<0.001).

Trends in mortality from acute myocardial infarction in the coronary care unit.

INTRODUCTION: The treatment and outcome of acute myocardial infarction (AMI) has evolved greatly over the past few decades. We compared the mortality and complication rates of patients with AMI admitted to the Coronary Care Unit (CCU) in 2002 to previously reported data. MATERIALS AND METHODS: All data for AMI patients admitted to National Heart Centre CCU in 2002 were collected through the Singapore Cardiac Data Bank, including demographics, in hospital complications and mortality. These were compared to previous reports from the same institution in 1988, 1975 and 1967. RESULTS: A total of 516 cases with AMI were identified. A higher proportion of patients were aged >or=70 years in 2002 (31.8%) compared to 1988 (25%), 1975 (11%) and 1967 (5.6%). Acute percutaneous transluminal coronary angioplasty (PTCA) was performed in 250 of 516 (48%) patients in 2002. The overall in-patient and age-standardised mortality was 14.7% and 10% respectively, compared to 20.6% and 17% respectively in 1988 (P = 0.06). For the 250 patients who underwent acute PTCA, overall mortality was 5.2% compared to 24% in those who did not (P <0.001). Common in-hospital complications included heart failure (38%), non-sustained ventricular tachycardia (8%), atrial fibrillation (8%) and complete heart block (6%). Age, heart failure, bundle branch block and sustained ventricular tachycardia were associated with higher mortality by univariate analysis. On multivariate analysis, older age, heart failure and the absence of percutaneous intervention were independently associated with higher mortality. CONCLUSION: In-hospital mortality for AMI patients admitted to the CCU declined from 1988 to 2002 despite a higher proportion of elderly patients. The introduction of new therapies including drugs and percutaneous intervention may have contributed to this decline.