cardiovascular disease is a growing health burden across asia and this is fuelled by increasing rates of diabetes mellitus , hyperlipidemia , hypertension , obesity and unhealthy life - style choices in the region .
, several countries in asia including singapore are also facing the silver tsunami which is associated with increased risk of cardiovascular complications .
, the local population in singapore is ageing rapidly as the number of persons aged  65 years will escalate from 9% in 2008 to approximately 19% of local population in 2030 .
the prevalence of cardiovascular disease is expected to rise and as a result , will pose a significant challenge and burden to the local health system .
previous cardiovascular studies have shown that elderly patients were less likely to receive evidence - based therapies and had higher mortality rate. there was also marked variation in the clinical care of the elderly with acute coronary syndromes ( acs). in addition , limited data are available on the delivery of health care and clinical outcomes of elderly patients with cardiovascular disease in the south - east asia region .
we therefore sought to evaluate the clinical characteristics and in - hospital outcomes of our cohort of elderly south - east asian patients undergoing primary percutaneous coronary intervention ( ppci ) for st - elevation myocardial infarction ( stemi ) in  real world  clinical practice .
from january 2009 to december 2012 , a total of 1268 consecutive patients were diagnosed with stemi and underwent ppci at our institution , a tertiary referral centre in singapore .
data were collected retrospectively on baseline clinical characteristics , presenting signs and symptoms , door - to - balloon ( d2b ) time , angiographic findings , therapeutic modality and hospital course .
all patients were treated with aspirin ( an oral loading dose of 300 mg followed by 100 mg daily ) prior to the procedure and indefinitely thereafter .
patients also received clopidogrel ( an oral loading dose of 300 mg followed by 75 mg daily ) before the procedure , followed by a minimum of four weeks in patients who received bare metal stent ( bms ) and one year in patients who received drug - eluting stent ( des ) .
additional duration of clopidogrel treatment was at the discretion of the attending physician . in our study
, we defined elderly as those with age  70 years and those aged < 70 years formed the comparison group .
myocardial infarction ( mi ) was defined according to the latest consensus on mi definition , along with the presence of typical symptoms , and/or electrocardiographic changes suggestive of infarction or ischaemia that was associated with a rise of cardiac troponins to at least twice the upper limit of the normal value .
the culprit lesion for stemi was identified based on morphology including complete occlusion , thrombus and ulcerative stenosis or assumed to be the tightest stenosis if these features were absent .
pci procedural success was defined as successful restoration of thrombolysis in myocardial infarction ( timi ) 3 flow after stenting or balloon angioplasty .
the major clinical outcomes ( in - hospital ) analysed in our study include all - cause mortality , killip iii - iv , major arrhythmia events ( complete heart block , atrial , and ventricular arrhythmias ) , cerebrovascular accident ( cva ) , sepsis and cardiogenic shock .
statistical comparisons were performed using the student t test , chi square test , or fisher 's exact test , as appropriate .
all investigations were carried out in accordance with the declaration of helsinki and the study was approved by the local ethics committee .
from january 2009 to december 2012 , a total of 1268 consecutive patients were diagnosed with stemi and underwent ppci at our institution , a tertiary referral centre in singapore .
data were collected retrospectively on baseline clinical characteristics , presenting signs and symptoms , door - to - balloon ( d2b ) time , angiographic findings , therapeutic modality and hospital course .
all patients were treated with aspirin ( an oral loading dose of 300 mg followed by 100 mg daily ) prior to the procedure and indefinitely thereafter .
patients also received clopidogrel ( an oral loading dose of 300 mg followed by 75 mg daily ) before the procedure , followed by a minimum of four weeks in patients who received bare metal stent ( bms ) and one year in patients who received drug - eluting stent ( des ) .
in our study , we defined elderly as those with age  70 years and those aged < 70 years formed the comparison group .
myocardial infarction ( mi ) was defined according to the latest consensus on mi definition , along with the presence of typical symptoms , and/or electrocardiographic changes suggestive of infarction or ischaemia that was associated with a rise of cardiac troponins to at least twice the upper limit of the normal value .
the culprit lesion for stemi was identified based on morphology including complete occlusion , thrombus and ulcerative stenosis or assumed to be the tightest stenosis if these features were absent .
pci procedural success was defined as successful restoration of thrombolysis in myocardial infarction ( timi ) 3 flow after stenting or balloon angioplasty .
the major clinical outcomes ( in - hospital ) analysed in our study include all - cause mortality , killip iii - iv , major arrhythmia events ( complete heart block , atrial , and ventricular arrhythmias ) , cerebrovascular accident ( cva ) , sepsis and cardiogenic shock .
statistical comparisons were performed using the student t test , chi square test , or fisher 's exact test , as appropriate .
calculations were performed using spss software ( version 16.0 ) . two sided significance level of 0.05 was chosen for all the tests .
all investigations were carried out in accordance with the declaration of helsinki and the study was approved by the local ethics committee .
table 1 summarizes the baseline clinical characteristics of the study population . for the overall study group ,
the mean age at presentation was 58.4  12.2 years , with male predominance ( 86.4% ) .
the elderly group constituted 19.4% of the study population with mean age 76.6  5.2 years . when compared to their younger counterparts , the elderly group more likely to be female , of chinese ethnicity , and
no significant differences were observed for both groups with respect to cardiovascular risk factors , such as diabetes mellitus , hyperlipidaemia , prior mi , prior pci or prior coronary artery bypass grafting ( cabg ) and end - stage renal failure on dialysis .
types of stemi presentation also did not differ in both groups but the mean left ventricular function was significantly lower in the elderly group . as for mode of presentation to hospital , both groups ( > 60% ) were equally likely to use emergency medical services ( ems ) rather than self - present to hospital .
data were expressed as mean  sd , n ( % ) or n. ami : acute myocardial infarction ; cabg : coronary artery bypass grafting ; ems : emergency medical services ; lvef : left ventricular ejection fraction ; mi : myocardial infarction ; pci : percutaneous coronary intervention . table 2 summarizes the d2b time , angiographic findings and procedural variables of the study population . for the overall study group ,
the elderly group had a significantly longer mean d2b time when compared to the non - elderly group .
the mean symptom onset to reperfusion time was numerically higher in the elderly group but was not statistically significant .
the former group had a higher proportion of triple vessel disease and occlusive left main disease on coronary angiography .
the most common target vessel for pci for the elderly group was right coronary artery ( rca ) whereas it was the left anterior descending artery ( lad ) for the non - elderly group .
femoral access ( > 70% ) was used more frequently than radial access in the elderly group when compared to the non - elderly group .
usage of glycoprotein iib / iiia inhibitors was also significantly lower in the former group .
the majority of patients ( > 80% ) in both groups underwent stenting during ppci but the elderly group were less likely to receive a des implantation .
pure old balloon angioplasty ( poba ) was also used more frequently in the elderly group .
table 3 summarizes the clinical outcomes ( in - hospital ) of the study population .
the elderly group had a significantly higher in - hospital mortality ( 11.9% vs. 3.6% ) when compared to their younger counterparts .
they were much sicker at presentation ( higher proportion of killip iii - iv ) and had a higher rate of cardiogenic shock thus requiring a higher use of iabp .
no difference was observed between both groups in terms of developing life - threatening ventricular arrhythmias .
however , the elderly group were more likely to develop atrial arrhythmias ( atrial fibrillation / flutter ) and complete heart block .
the most common cause of sepsis in both groups was pneumonia followed by urinary tract infection .
there were increased bleeding episodes ( 18.8% vs. 8.1% ) in the elderly group patients when compared to their younger counterparts . significant bleeding ( timi i - ii ) also occurred at a higher rate in the elderly group compared to the younger population ( 13.9% vs. 3.7% ) .
as asia braces for an unprecedented  silver tsunami  , increasing numbers of elderly patients are seeking medical care for acs or symptoms of cardiovascular disease . , the clinical outcomes of elderly patients who undergo pci especially for asian patients remains under - represented in the published literature. elderly patients represented 19.4% of our study population and to our knowledge , this is the first observational study reporting the clinical outcomes of elderly stemi patients undergoing ppci in real world clinical practice in the south - east asian region .
data were expressed as mean  sd , n ( % ) or n. bms : bare metal stent ; circ : left circumflex ; des : drug - eluting stent ; d2b : door - to - balloon ; iabp : intra - aortic balloon pump ; gpiibiiia : glycoprotein iib / iiia inhibitors ; lad : left anterior descending artery ; poba : pure old balloon angioplasty ; rca : right coronary artery . data were expressed as mean  sd , n ( % ) .
af : atrial fibrillation ; cva : cerebrovascular accident ; iabp : intra - aortic balloon pump ; pci : percutaneous coronary intervention ; timi : thrombolysis in myocardial infarction ; uti : urinary tract infection ; vf : ventricular fibrillation ; vt : ventricular tachycardia .
the elderly group in our study more likely to be female , have a higher rate of hypertension but were less likely to be smokers .
this is partially consistent with the findings of other studies that have shown elderly patients are often female , have higher rate of hypertension , diabetes mellitus , prior mi and prior cabg .
, there are more chinese in the elderly group of patients in singapore which is likely a reflection of the local ethnic composition .
singapore is a south - east asian city - state which has a multiethnic population of 5.5 million .
based on the government census report , the ethnic compositions of malays , chinese and indians in the general population were 13.4% , 74.2% and 9.2% , respectively .
the elderly group in our study had a significantly longer mean d2b time when compared to non - elderly group although the symptom onset to reperfusion time was similar in both groups .
a major reason for the delay in d2b as reported by prior studies is due to the atypical presentation of acs in the elderly which is often non - specific .
, dyspnoea is the more common presenting complaint compared to precordial chest pain and they could also present with epigastric discomfort , giddiness or delirium . barriers to effective communication and proper consent taking such as impaired hearing function , vision and cognitive function , could also potentially prolong d2b time . in asia
hence , informed consent for procedures is commonly shared between various family members and the patient .
these factors may lead to delay in consent - taking , thus resulting in delay in medical intervention .
the elderly group also had a higher proportion of triple vessel disease and occlusive left main disease on coronary angiography when compared to their younger counterparts .
this finding is consistent with prior studies and is likely a clinical manifestation of the natural history of coronary atherosclerosis , i.e. , an age - dependent chronic inflammatory process. in our study , femoral access ( > 70% ) was used more frequently as a default route than radial access in the elderly group when compared to the non - elderly group .
this is likely due to selection bias as the elderly patients tend to have weaker radial pulses because of advanced atherosclerosis and much sicker at presentation , thus precluding radial access .
age should not be a barrier to transradial access for pci if feasible as studies have shown better clinical outcomes with transradial approach compared to transfemoral approach. the majority of patients ( > 80% ) in both groups underwent stenting during ppci but the elderly group was less likely to receive a des implantation .
pure old balloon angioplasty was used more frequently in the elderly group and usage of glycoprotein iib / iiia inhibitors was also significantly lower .
this could be explained by concerns of increased bleeding risks in the elderly and their inability to tolerate prolonged dual anti - platelet therapy ( dapt ) .
there have been several studies which have reported advanced age as a predictor of bleeding and mortality .
there were increased bleeding episodes in the elderly group patients when compared to their younger counterparts ( 18.8% vs. 8.1% ) .
significant bleeding ( timi bleeding i - ii ) also occurred at a higher rate in the elderly group compared to the younger population ( 13.9% vs. 3.7% ) .
the elderly group of patients may potentially benefit from the advent of newer generation des especially polymer - free des which is safe with a shorter duration of dapt and associated with better outcomes when compared to bms .
prior studies have shown that age - dependent inequalities are apparent in the management of acs with elderly patients less likely to undergo cardiac catheterisation and pci. in singapore , ppci is the default reperfusion therapy for patients with stemi and there 's no age limit even for elderly patients ( oldest patient in our study was 94 years old ) . despite getting full access to ppci , the mortality rate is quite high ( 11.9% ) in our cohort of elderly patients when compared to their younger counterparts .
this is consistent with the findings of previous studies that had demonstrated that increased age was associated with higher in - hospital morbidity and mortality. by multivariate analysis , elderly group was an independent predictor of in - hospital mortality in our study with an odds ratio of 3.1 ( 95% confidence interval : 1.75.6 ; p = 0.001 ) .
aging inevitably causes a number of physiological and morphological changes in the body that can alter cardiovascular function . as a result of multiple co - morbidities ,
elderly patients have lower cardiac reserve and lower capacity to recover from acute cardiac injury than their younger counterparts .
the elderly group in our study was much sicker at presentation ( higher proportion of killip class iii - iv ) , had more extensive coronary artery disease , a longer d2b time and received lower use of contemporary pharmaco - invasive treatment during ppci .
they were also more prone to develop major in - hospital complications like tachy - bradyarrhythmias , sepsis and bleeding complications when compared to the younger group .
pci procedural failure is associated with advanced age but this was not observed as a contributory factor for higher rate of in - hospital mortality in our study ( table 3 ) .
we also did not capture data on the prevalence of antecedent risk factors like atrial fibrillation , previous cva , peripheral vascular disease and chronic obstructive lung disease which may impact clinical outcomes especially in the elderly group . despite having an advanced medical health system in singapore
, our registry showed that the in - hospital mortality rate in elderly south - east asian patients undergoing ppci for stemi was high .
they had more extensive coronary artery disease , a longer d2b time and lower use of contemporary pharmaco - invasive treatment during ppci which could account for their poorer prognosis .
our sample size was relatively small when compared to other studies . moreover , our study was a retrospective , single - centre observational study .
we also did not capture data on the prevalence of antecedent risk factors like atrial fibrillation , previous cva , peripheral vascular disease and chronic obstructive lung disease which may impact clinical outcomes especially in the elderly group .
despite having an advanced medical health system in singapore , our registry showed that the in - hospital mortality rate in elderly south - east asian patients undergoing ppci for stemi was high .
they had more extensive coronary artery disease , a longer d2b time and lower use of contemporary pharmaco - invasive treatment during ppci which could account for their poorer prognosis .
 objectiveto evaluate the clinical characteristics and in - hospital outcomes of elderly south - east asian patients undergoing primary percutaneous coronary intervention ( ppci).methodsfrom january 2009 to december 2012 , 1268 patients ( 86.4% male , mean age of 58.4  12.2 years ) presented to our hospital for st - elevation myocardial infarction ( stemi ) and underwent ppci . they were divided into two groups : elderly group defined as age  70 years and non - elderly group defined as age < 70 years . 
 data were collected retrospectively on baseline clinical characteristics , door - to - balloon ( d2b ) time , angiographic findings , therapeutic modality and hospital course.resultsthe elderly group constituted 19% of the study population with mean age 76.6  5.0 years . 
 there was a higher proportion of female gender and ethnic chinese patients in the elderly group when compared with the non - elderly group . 
 the former was less likely to be smokers and have a significantly higher prevalence of hypertension . 
 the mean d2b time was significantly longer in the elderly group . 
 they also had a significantly higher incidence of triple vessel disease and obstructive left main disease . 
 the use of radial artery access , glycoprotein 2b/3a inhibitors and drug - eluting stents during ppci were also significantly lower . in - hospital 
 mortality was significantly higher in the elderly group . 
 the rate of cardiogenic shock and inhospital complications were also significantly higher.conclusionsour registry showed that in - hospital mortality rate in elderly south - east asian patients undergoing ppci for stemi was high . 
 further studies into the optimal stemi management strategy for these elderly patients are warranted . 
Introduction
Methods
Study population and design
Interventional procedure
Definitions and outcomes
Statistical analysis
Results
Discussion
Study limitations
Conclusions