|Year : 2020 | Volume
| Issue : 4 | Page : 139-144
The clinical and coronary angiographic profile of 601 older adult patients with acute coronary syndrome treated at a tertiary hospital in North India and complications of percutaneous coronary intervention with the 30-day mortality
Umar H Khan1, Murtaza R Pala1, Imran Hafeez2, Afshan Shabir1, Aamir Rashid2, Nisar Tramboo2, Hilal Rather2
1 Department of Geriatric Medicine, Sher.i.Kashmir Institute of Medical Sciences, Srinagar, Jammu and Kashmir, India
2 Department of Cardiology, Sher-i-Kashmir Institute of Medical Sciences, Srinagar, Jammu and Kashmir, India
|Date of Submission||31-Jul-2020|
|Date of Decision||31-Dec-2020|
|Date of Acceptance||09-Jan-2021|
|Date of Web Publication||23-Feb-2021|
Dr. Afshan Shabir
Department of Geriatric Medicine, Sher-i-Kashmir Institute of Medical Sciences, Soura, Srinagar - 190 011, Jammu and Kashmir
Source of Support: None, Conflict of Interest: None
Aims: The aim is to identify clinical and coronary angiographic (CAG) profile of older adult patients with the acute coronary syndrome (ACS), assess complications of percutaneous coronary intervention (PCI) and the 30-day mortality. Materials and Methods: This was a prospective observational study of 601 older adult patients with ACS who underwent CAG over 2 years (2017–2019). The study population was divided into two groups: the young, old group (60–70-year-old), and the old group (>70-year-old). Results: Mean age of presentation was 77 ± 17 years. The majority were males 486 (80.9%). Presenting symptoms was chest pain (94.8%), followed by diaphoresis (33%) and dyspnea (27.4%). ST-elevation myocardial infarction (STEMI) was seen in 377 (62.7%) of the study population, followed by non-STEMI 176 (29.2%) and unstable angina (UA) in 48 (7.9%) patients. Hypertension was the most prevalent risk factor (78%) in the study population. The left anterior descending artery (LAD) was most commonly involved vessel in 415 patients (69.1%) followed by right coronary artery 322 (53.6%) and left circumflex artery 240 (39.9%). Contrast nephropathy (contrast-induced nephropathy [CIN]) occurred in 3.3%, and intra cerebral hemorrhage (ICH) was seen in one patient only. The 30-day mortality was 2.7% in 60–70 years and 14.1% in >70 years. Conclusion: Older patients with ACS differ from their younger counterparts in their clinical presentation, comorbidities, and outcome. Elderly patients can present with atypical symptoms. The 30-day mortality was higher in patients presenting with atypical symptoms, which was statistically significant in multivariate analysis. Like their younger counterparts, most older ACS patients had single-vessel disease, and the most common vessel involved was the LAD. Overall mortality was 5.3%. Even though elderly patients have a high coronary risk because of associated comorbidities, this study proves that PCI's CAG (if indicated) resulted in fewer CIN and ICH complications in older patients with ACS.
Keywords: Acute coronary syndrome, coronary angiogram, myocardial infarction, older adults, percutaneous coronary intervention
|How to cite this article:|
Khan UH, Pala MR, Hafeez I, Shabir A, Rashid A, Tramboo N, Rather H. The clinical and coronary angiographic profile of 601 older adult patients with acute coronary syndrome treated at a tertiary hospital in North India and complications of percutaneous coronary intervention with the 30-day mortality. J Indian Acad Geriatr 2020;16:139-44
|How to cite this URL:|
Khan UH, Pala MR, Hafeez I, Shabir A, Rashid A, Tramboo N, Rather H. The clinical and coronary angiographic profile of 601 older adult patients with acute coronary syndrome treated at a tertiary hospital in North India and complications of percutaneous coronary intervention with the 30-day mortality. J Indian Acad Geriatr [serial online] 2020 [cited 2023 Mar 21];16:139-44. Available from: http://www.jiag.com/text.asp?2020/16/4/139/309995
| Introduction|| |
The United Nations Population Division has projected that the population over 65 years will reach 11% by 2025. India is expected to have around 157 million older persons by then, and this number will nearly double to 297 million by 2050, constituting 18% of India's population. Cardiovascular diseases are the leading contributors to disease burden in the older population (28.1%) of the total burden in people 60 years and older). About 85% of acute myocardial infarction (AMI) deaths occur in the elderly. Clinical studies have incorporated minimal numbers of people in the geriatric age group, and some studies did not have >10% representation from this age group., The elderly with the acute coronary syndrome (ACS) often have a different risk profile from the non-elderly. They have a higher prevalence of arterial hypertension, diabetes mellitus, myocardial infarction, angina, peripheral vascular disease, cerebral vascular accident, arterial disease, and heart failure. In the event of ACS, instead of chest pain, they can also have the so-called “ischemic equivalents” such as dyspnea, malaise, confusion, syncope, or pulmonary edema. In elderly patients, percutaneous coronary intervention (PCI) is used for revascularization as appropriate. Heterogeneity of the composition, distribution, and location of atherosclerotic plaque within the coronary arteries also help predict procedural outcome and complications after PCI.
The study is aimed to identify the clinical and coronary angiographic (CAG) profiles of older adult patients with ACS and explore any potential interactions between gender and underlying comorbidities such as diabetes, smoking, and hypertension about the risk of fatal AMI. We also assessed PCI complications and 30-day mortality as the secondary outcomes of the study.
| Materials and Methods|| |
This was a prospective observational study carried out in patients with ACS. They were admitted in SKIMS (Sheri Kashmir Institute of Medical Sciences) over 2 years (2017–2019) and underwent CAG. The Ethics Committee approved this study, and the informed written consent was obtained from the patients. The study population was divided into two groups: the young, old group (60–70-year-old), and the old group (>70-year-old). As per their clinical presentation, patients were labeled ACS with typical symptoms or ischemic equivalents (atypical manifestations of ACS as dyspnea, diaphoresis, syncope, or peripheral edema). ACS was divided into ST-elevation myocardial infarction (STEMI), ACS without ST-segment elevation (non-ST-elevation myocardial infarction [NSTEMI]) and unstable angina (UA).
Risk factors for CAD were documented at the time of catheterization by completing a questionnaire. The angiographic characteristics include the extent of CAD (characterized by the number of vessels with angiographic lesion over 50.0% - one, two or three-arteries), treated vessel (if native coronary, venous/arterial or vessel graft with restenosis) were documented and analyzed. Patients were followed up during hospitalization to highlight complications associated with both diagnostic and therapeutic procedures. The complications studied were cerebrovascular accidents, contrast-induced nephropathy (CIN), and death. The 30-day mortality post-PCI was also assessed.
Demographic and other background data were summarized with basic descriptive statistics in all patients. Recorded data were compiled and entered in a spreadsheet (Microsoft Excel) and then exported to the data editor of SPSS Version 20.0 (SPSS Inc., Chicago Illinois, USA). Baseline characteristics were compared between groups using the Chi-square test for categorical variables and Student's t-test for continuous variables as appropriate. Results were reported as means ± SD, medians with range or percentages as appropriate. Those variables which had a P < 0.25 in univariate analysis were included in multivariate COX regression analysis. The backward stepwise likelihood ratio method was used to identify the independent predictors of 30-day mortality. All tests were two-tailed, and a value of P < 0.05 was considered statistically significant.
| Results|| |
Out of 601 ACS patients, most were male 486 (80.9%) [Table 1]. 272 patients (45.3%) were from a rural background, 220 patients were 60–70 years, and 52 patients were >70 years old, 339 patients (54.7%) were from an urban background, 247 patients were 60–70 years, and 82 patients were >70 years old.
|Table 1: Demography, presenting symptoms, risk factors and comorbidities|
Click here to view
Presentation on admission
Chest pain (93.5%) was the most common presenting symptom followed by diaphoresis (33.8%), dyspnea (27.8%), vomiting (5.8%), and syncope (5.3%) [Table 1].
Risk factors and comorbidities associated with acute coronary syndrome
A total of 469 (78%) patients were hypertensive (P = 0.033), 271 patients (47.1%) were current smokers, dyslipidemia was present in 358 (59.6%) of the patients, and 198 (32%) patients had diabetes. Family history of CAD was present in 56 (9.3%) patients [Table 1]. STEMI 377 (62.7%) was the most common presentation, followed by NSTEMI 176 (29.2%) and UA 48 (7.9%).
Among patients with UA, single-vessel disease (SVD) was seen in 23 (47.9%) patients, double-vessel disease (DVD) in 16 (33.3%) patients and triple-vessel disease (TVD) in 9 (18.7%) patients. In NSTEMI, SVD was present in 79 (44%), DVD in 51 (28.9%) and TVD in 46 (26.1%). In STEMI, SVD was seen in 216 (57.2%), DVD in 105 (27.8%) and TVD in 56 (14.8%).
People with diabetes showed a trend toward multi-vessel disease as compared to non-diabetic. DVD was seen in 61 (30.8%) of diabetics, whereas it was seen in 111 (27.5%) of non-diabetics. TVD was present in 38 (19.1%) of diabetics and 73 (18.1%) non-diabetic patients.
Left anterior descending artery (LAD) (69.1%) was the most common vessel involved, followed by the right coronary artery (RCA) (53.6%) and left circumflex artery (LCX)(39.9%), whereas LMCA (2%) was minimally involved, in both the age groups [Table 2].
Percutaneous coronary intervention
Primary PCI was performed in 77 (11.8%) patients. Forty-seven patients out of these presented to secondary care hospitals in remote areas and had initial thrombolysis. Elective PCI was performed in 524 (87.2%) patients. In total, 565 patients had successful stent deployment, and reperfusion and 36 patients were referred for coronary artery bypass grafting.
After percutaneous coronary intervention, complications and 30-day mortality
A total of 32 (5.3%) patients died post PCI. Mortality was seen in female patients 11/104 (9.5%) as compared to male patients 21/486 (4.32%) (P < 0.024). The 30-day mortality was 2.7% in 60–70 years and 14.1% in >70 years, which was statistically significant (P < 0.0001). Twenty patients (3.3%) developed CIN (measured as either a 25% increase in serum creatinine from baseline or a 0.5 mg/dl increase in absolute serum creatinine value within 48–72 h after intravenous contrast administration within), and only 1 case developed intracerebral hemorrhage post PCI [Table 3]. Elderly ACS patients presenting with symptoms of chest pain and diaphoresis [Table 4].
|Table 3: Complications of percutaneous coronary intervention in study patients|
Click here to view
On multivariate binary logistic regression analysis, the 30-day mortality was higher in patients presenting with atypical dyspnea symptoms, syncope, vomiting, and diaphoresis, which were statistically significant [Table 5].
| Discussion|| |
Coronary artery disease (CAD) is a significant medical and public health problem with approximately 7.2 million deaths/year worldwide annually due to rapid urbanization, lifestyle change, and economic growth. The factors affecting the course of MI in the elderly have not been studied in detail. The clinical picture of MI in elderly patients differs in many aspects compared to younger patients. Compared to young-old patients, old patients may have a certain atypical presentation. Some patients can present with syncope as in our study, while others may present with congestive cardiac failure features. It has been shown that older populations are more frequent symptoms of heart failure exacerbation. Typical symptoms of chronic heart failure exacerbation are often accompanied by dizziness, pre-syncope, and syncope. Some studies have shown that 75% of patients over 85 with MIs did not complain about chest pain in MI's acute phase. When classic ischemic precordial discomfort is there, it is less severe and less well defined. The elderly appear to have reduced pain perception. This phenomenon may result from an increased pain threshold of permanently ischemic sensory nerves, ischemic dysfunction of the cerebral cortex, and dysfunction of the autonomic nervous system. However, this study showed that most patients (93.5%) complained of chest pain.
The prevalence of hypertension was 78% compared to the South Asian cohort of the INTERHEART study (31.1%)., It was 76% in 60–70-year-old and higher 85.10% in >70 years. The present study showed that there was a higher prevalence of hypertension (hypertension, defined as blood pressure ≥140/90 mmHg (P < 0.05) in the old (>70 years) and low prevalence of dyslipidemia compared to patients < 70 years of age. These results are in concordance with studies done by Goch et al. They also had a high prevalence of hypertension and low prevalence of dyslipidemia. Hypertension is known to cause left ventricular hypertrophy that probably leads to early MI symptoms and forces patients to seek medical care, hence being recorded more frequently in patients admitted with MI.,
In the present study, 45.1% of the patients were current smokers. These patients had STEMI more commonly compared with UA/NSTEMI. Smoking was more prevalent in males (52.7%) compared to females (13%) which was statistically significant (P < 0.0001). This is due to the high prevalence of smoking among males compared to females in the general population. The INTERHEART study also identified smoking as the second-most important risk factor for AMI worldwide. The detrimental effects of smoking on the cardiovascular system seem to act by promoting vasomotor dysfunction, atherogenesis (e.g., inflammation and dyslipidemia), and thrombosis in multiple vascular beds mediated oxidative stress.
Diabetes is the most critical AMI predictor, probably through its association with preexisting left ventricular dysfunction and diffuse and rapidly progressive coronary atherosclerosis. The peak incidence of ACS in people with diabetes was seen in the eight decades. The prevalence of diabetes was 32.9% in our study, which is similar to the prevalence in the INTERHEART study. This was lower than the Indian study by Gupta and Gupta The incidence of DM in ACS varies from 10.5% to 30.0% reported in the studies conducted in white patients and the Asian population in the United Kingdom. The prevalence of diabetes mellitus was equal in females (33%) and males (32.9%). The skewed gender distribution of males (81% vs. 19.1%) versus females in the present study population has also been observed in the INTERHEART study and its South Asian cohort (overall male, 76% and South Asian cohort, 85%). Whereas AMI's overall incidence is lower in women, the female advantage disappears in subjects with type 2 diabetes. The risk is sometimes even considered higher in women than in men. The INTERHEART study has also shown a stronger association between female gender and diabetes. The risk of CHD in subjects with diabetes is about doubled when looking at men and women together. It seems to affect several interacting metabolic changes in the pre-diabetic state, such as the development of atherogenic dyslipidemia, impaired endothelial function, increased levels of free fatty acids, subclinical inflammation, changes in adipokines, and changes in thrombosis and fibrinolysis.
Family history of ACS was present in 9.3% of patients. The family members share genes and share living habits and environment, increasing the risk of MI in the family members. Genome-Wide Association Studies have found the genetic base for the MI to be a complex interplay between a few known and many as of yet unknown genes and environmental influences.
CAD was more common in the urban population than rural (P = 0.02) replicating a similar study by Gupta and Gupta. The sedentary lifestyle is essential in caloric imbalance, resulting in obesity and all consequences of obesity. In the past three decades, the prevalence of CAD has increased from 1.1% to about 7.5% in the urban population and from 2.1% to 3.7% in the rural population.,
CAG was done in all 601 study participants. Even though older patients constitute a high coronary risk, numerous observations and studies proved that these patients benefit significantly from PCI in acute MI. Our study revealed a preponderance of SVD in all age groups of ACS including UA/NSTEMI and STEMI followed by DVD and TVD among both sexes, which had also been reported by other studies. Compared to older patients, multi-vessel diseases are less prevalent in the younger cohort. LAD (69.1%) was the most common vessel involved followed by RCA and LCX, similar to a study by Saghir and Sial, that also found a high prevalence of LAD diseases (58%) in the elderly. Prajapati et al. showed LAD was the most commonly involved vessel among young patients with ACS; LCx was the most frequently involved vessel among older patients with ACS. There was a relatively low prevalence of TVD and high prevalence of SVD in STEMI (P = 0.01) compared to NSTEMI and UA; similar results were shown by Prajapati et al.
The older group had more common TVD (24.6%) compared to the young-old (16.7%), which was statistically significant (P = 0.037), due to many factors, including age and comorbidities, such as the increased prevalence of hypertension and diabetes in older patients. The relatively high prevalence of DVD (30.8%) and TVD (19.1%) in diabetic patients, when compared with non-diabetics, suggests the role of diabetes as a risk factor in CAD (diabetes increase atherosclerotic plaque formation and thrombosis, thereby contributing to myocardial infarction). Others have also reported diabetes to be a predictor of the presence of multi-vessel diseases. STEMI 377 (62.7%) was the most common presentation followed by NSTEMI 176 (29.2%) and UA 48 (7.9%) in our study contrary to other studies that have shown NSTEMI is the most typical presentation in the elderly. This could be explained by referral bias, ours being a tertiary referral hospital, and patients with STEMI are often more symptomatic and prefer treatment in tertiary care hospitals.
The older patients account for a large proportion of patients undergoing PCI. It has been shown that older patients have an increased incidence of PCI-related complications. In our study, post-PCI death occurred in 32 (5.3%), CIN in 20 patients (3.3%), and intracranial hemorrhage in 1 patient (0.16%). Hence, the present study showed that PCI could be done with a reasonable degree of safety with fewer complications and mortality in older patients with ACS. Pre-existing renal insufficiency, diabetes, and age were the most significant risk factors for developing CIN. A similar result was shown by Rudnick et al., where 3% of patients developed CIN with underlying CKD and Diabetes. CIN can be reduced with proper hydration before PCI. Mehran et al. assessed the risk factors for CIN, determining a score for stratification of risk for the development of acute renal failure after PCI.
In the current study, 30-day mortality rates have remained acceptable (5.3%) despite high-risk patients taken for PCI. Patients who died presented with atypical symptoms such as dyspnea, syncope, diaphoresis, and vomiting, which was statistically significant on multivariate analysis [Table 5]. Patients with dyspnea had OR of 3.38, 95% CI 1.45–7.88 with a P = 0.005. Patients presenting with syncope and vomiting had OR of 6.83, 95% CI 2.50–18.69, P = 0.00 0.00 and OR 9.09, 95% CI 3.26–25.39, P = 0.00, respectively. The 30-day mortality was higher in >70 years of age than 60–70 years (14.1% vs. 2.7%). In-hospital mortality was higher in female patients (9.5%). The most common presentation among ACS patients who died was STEMI (65.6%) in comparison to UA or NSTEMI. A high prevalence of DVD (43.8%) P < 0.05 is partially accounted for by the high prevalence of hypertension and diabetes in older patients. Sinkovic et al. also showed high mortality in elderly patients with STEMI.
| Conclusion|| |
Elderly patients with ACS differ from younger patients in their clinical presentation, comorbidities, and outcomes. Elderly patients can present with atypical symptoms like diaphoresis, vomiting, syncope, and dyspnea. Hypertension was the most common risk factor for ACS in our population. As per CAG results, the majority had single-vessel disease involvement, and the LAD artery was the most common vessel implicated. In the current study, 30-day mortality rates have remained acceptable (5.3%) despite high-risk patients taken for PCI. The 30-day mortality was higher in patients presenting with atypical symptoms which were statistically significant. The prevalence of ACS is continuously increasing due to the growing life expectancy and increasing rates of cardiovascular risk factors. Even though elderly patients have a high coronary risk because of associated comorbidities, this study proves that PCI's CAG (if indicated) resulted in fewer CIN and intracerebral hemorrhage post-MI complications in older patients with ACS.
Factors such as detailed dietary habits and exercise schedules were not included, as the primary aim was to study the clinical correlation with the ACS patients' angiographic profile. The cognition of the patients was not assessed. The main limitation of this study was the lack of long-term follow-up.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
United Nations. World Population Ageing, Department of Economic and Social Affairs. United Nations: World Population Division; 2013.
India State-Level Disease Burden Initiative CVD Collaborators. The changing patterns of cardiovascular diseases and their risk factors in India's states the Global Burden of Disease Study 1990-2016. The Lancet 2018;6 https://doi.org/10.1016/S2214-109X(18)30407-8
Alexander KP, Anstrom KJ, Muhlbaier LH, Grosswald RD, Smith PK, Jones RH, et al
. Outcomes of cardiac surgery in patients >or=80 years: Results from the national cardiovascular network. J Am Coll Cardiol 2000;35:731-8.
Teo KK, Ounpuu S, Hawken S, Pandey MR, Valentin V, Hunt D, et al
. Tobacco use and risk of myocardial infarction in 52 countries in the INTERHEART study: A case-control study. Lancet 2006;368:647-58.
Huxley R, Barzi F, Woodward M. Excess risk of fatal coronary heart disease associated with diabetes in men and women: A meta-analysis of 37 prospective cohort studies. BMJ 2006;332:73-8.
John FB, Rachel D, Rosanna T. Epidemiology of coronary artery disease. In: David G, editor. Coronary Artery Disease-Current Concepts in Epidemiology, Pathophysiology, Diagnostics and Treatment. London: InTech; 2012.
Sokolik S, Tresch D. Treatment of myocardial infarction in elderly patients. Computer 1994;20:537-44.
Ryan TJ, Faxon DP, Gunnar RM, Kennedy JW, King SB 3rd
, Loop FD, et al
. Guidelines for percutaneous transluminal coronary angioplasty. A report of the American College of Cardiology/American Heart Association task force on assessment of diagnostic and therapeutic cardiovascular procedures (subcommittee on percutaneous transluminal coronary angioplasty). Circulation 1988;78:486-502.
Randomised intravenous streptokinase, oral aspirin, both, or neither among 17,187 cases of suspected acute myocardial infarction: ISIS-2. ISIS-2 (Second International Study of Infarct Survival) Collaborative Group. Lancet 1988;2:349-60.
Effect of intravenous APSAC on mortality after acute myocardial infarction: Preliminary report of a placebo-controlled clinical trial. AIMS Trial Study Group. Lancet 1987;10:1357-60.
Paul DS, O'Gara PT, Mahjoub ZA, DiSalvo TG, O'Donnell CJ, Newell JB, et al
. Geriatric patients with acute myocardial infarction: Cardiac risk profiles, presentation, thrombolysis, coronary interventions, and prognosis. Am Heart J 1996;131:7105.
Akiyama J, Aonuma K, Nogami A, Hiroe M, Marumo F, Iesaka Y. Thrombolytic therapy can reduce the arrhythmogenic substrate after acute myocardial infarction: A study using the signal-averaged electrocardiogram, endocardial catheter mapping and programmed ventricular stimulation. Circ J 1999;63:838-42.
Gregorios G. Clinical manifestations of acute myocardial infarction in older patients. Am J Geriatr Cardiol 2001;10:345-7.
Miller PF, Sheps DS, Bragdon EE, Herbst MC, Dalton JL, Hinderliter AL, et al
. Aging and pain perception in ischemic heart disease. Am Heart J 1990;12:22-7.
Gupta R, Gupta VP. Meta-analysis of coronary heart disease prevalence in India. Indian Heart J 1996;48:241-5.
Xavier D, Pais P, Devereaux PJ, Xie C, Prabhakaran D, Reddy KS, et al
. Treatment and outcomes of acute coronary syndromes in India (CREATE): A prospective analysis of registry data. Lancet 2008;371:1435-42.
Goch A, Misiewicz P, Rysz J, Banach M. The clinical manifestation of myocardial infarction in elderly patients. Clin Cardiol 2009;6:E46-51.
Chesbro JH, Knatterud G, Roberts R, Borer J, Cohen LS, Dalen J, et al
. Thrombolysis in myocardial infarction (TIMI) trial. Phase I: A comparison between intravenous tissue plasminogen activator and intravenous streptokinase. Circulation 1987;76:142-54.
Sadowski M, Gasior M, Gierlotka M, Janion M, Poloński L. Gender-related differences in mortality after ST-segment elevation myocardial infarction: A large multicentre national registry. EuroIntervention 2011;6:1068-72.
Yusuf S, Hawken S, Ounpuu S, Dans T, Avezum A, Lanas F, et al
. Effect of potentially modifiable risk factors associated with myocardial infarction in 52 countries (the INTERHEART study): Case-control study. Lancet 2004;364:937-52.
Eckel RH, Grundy SM, Zimmet PZ. The metabolic syndrome. Lancet 2005;365:1415-28.
The Emerging Risk Factor Collaboration; Sarwar N, Gao P, Seshasai SR, Gobin R, Kaptoge S, et al
. Diabetes mellitus, fasting blood glucose concentration, and risk of vascular disease: A collaborative meta-analysis of 102 prospective studies. Lancet 2010;375:2215-22.
Laakso M. Cardiovascular disease in Type 2 diabetes from population to man to mechanisms. The Kelly West award lecture 2008. Diabetes Care 2010;33:442-9.
Kathiresan S, Srivastava D. Genetics of human cardiovascular disease. Cell 2012;148:1242-57.
Matetzky S, Sharir T, Moc M, Domingo M, Chyu K, Kar S, et al
. Primary angioplasty for acute myocardial infarction in octogenarians. Am J Cardiol 2001;88:680-3.
Tewari S, Kumar A, Kapoor A, Singh U, Agarwal A, Bharti BB, et al
. Premature coronary artery disease in North India: An angiographic study of 1971 patients. Indian Heart J 2005;57:311-8.
Saghir T, Sial JQ. Coronary angiographic characteristic of coronary artery disease in young adults under age forty years compared to those over age forty. Pak Heart J 2008;41:49-56.
Prajapati J, Joshi H, Sahoo S, Virpariya K, Parmar M, Shah K. Age-related differences of novel atherosclerotic risk factors and angiographic profile among Gujarati acute coronary syndrome patients. J Clin Diagn Res 2015;9:OC05-9.
Singh M, Peterson ED, Roe MT, Ou FS, Spertus JA, Rumsfeld JS, et al
. Trends in the association between age and in-hospital mortality after percutaneous coronary intervention: National cardiovascular data Registry experience. Circ Cardiovasc Interv 2009;2:20-6.
Rudnick MR, Goldfarb S, Wexler L, Ludbrook PA, Murphy MJ, Halpern EF, et al
. Nephrotoxicity of ionic and non-ionic contrast media in 1196 patients: A randomised trial. The Iohexol cooperative study. Kidney Int 1995;47:254-61.
Wison S, Foo K, Cunningham J, Cooper J, Deaner A, Knight C, et al
. Renal function and risk stratification in acute coronary syndromes. Am J Cardiol 2003;91:1051-4.
Mehran R, Among ED, Nikolsky E, Lasic Z, Iakovou I, Fahy M, et al
. A simple risk score for predicting contrast-induced nephropathy after percutaneous coronary intervention: Development and initial validation. J Am Coll Cardiol 2004;44:1393-9.
Sinkovic A, Pehnec Z. In-hospital mortality and treatment in elderly patients with ST-elevation myocardial infarction. J Kardiol 2005;12:11-2.
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]