This study will evaluate clinical characteristics, frailty, and predictors of prognosis in patients aged 75 years and older who are hospitalized with acute coronary syndrome (ACS). The research includes both a retrospective and a prospective cohort. The aim is to determine whether frailty scores, combined with clinical and laboratory parameters available at admission, can improve risk prediction for complications and mortality compared with standard risk scores (TIMI, GRACE, Syntax). The study will also compare outcomes between patients treated with percutaneous coronary intervention (PCI) and those treated conservatively with medications. Patients will be followed during hospitalization and for six months after discharge. The results are expected to contribute to more personalized treatment strategies for elderly patients with ACS.
This observational study will evaluate clinical characteristics,frailty, and prognostic predictors in patients aged 75 years and older hospitalized with acute coronary syndrome (ACS). The study is designed with two complementary components: Retrospective cohort (≈350 patients): Data will be collected from electronic medical records of patients previously hospitalized with ACS. Variables include demographics, comorbidities, laboratory findings (hematology, biochemistry, cardiac biomarkers), ECG changes, echocardiographic parameters, and coronary angiography results. Standard risk scores (TIMI, GRACE, Syntax) will be compared with observed outcomes. Data integrity will be ensured through double-entry verification, and missing values will be addressed using multiple imputation. Prospective cohort (≈800 patients): Patients will be consecutively enrolled at admission with ACS. Data collection will include the same parameters as in the retrospective cohort, with additional dynamic laboratory monitoring and frailty assesment. Frailty will be assessed within 48 hours of admission using the Rockwood Frailty Scale, performed by trained investigators. Echocardiography and coronary angiography will be conducted according to institutional protocols. Patients will be followed during hospitalization and 6 months after discharge, using structured case report forms and telephone interviews. Outcomes will include major adverse cardiovascular events (MACE), all-cause mortality, rehospitalizations, PCI-related complications (vascular, gastrointestinal bleeding, neurological), and treatment adherence. Data management and statistical analysis: All data will be entered into a secure, password-protected database with regular quality control checks. Statistical analyses will be performed using SPSS v.27 and R. Methods include descriptive statistics, univariate and multivariate logistic regression, ROC curve analysis, and comparison of AUC values. Predictors identified in the retrospective cohort will be validated in the prospective cohort. The study team consists of cardiologists, statisticians, and trained research staff responsible for patient enrollment, frailty assessment, and data monitoring. Complications and adverse events will be defined according to standardized cardiology guidelines and adjudicated by an independent committee. The study is conducted in accordance with the Declaration of Helsinki. Retrospective data collection does not require informed consent, while prospective participants will provide written informed consent. The expected contribution is improved risk stratification and more personalized therapeutic approaches for elderly patients with ACS.
Study Type
OBSERVATIONAL
Enrollment
550
Patients receiving PCI as part of routine clinical care
Patients treated conservatively with guideline-directed medical therapy as part of routine care
Clinical Center Niš
Niš, Serbia
Impact of treatment strategy (PCI vs conservative therapy) on on all-cause mortality and major adverse cardiovascular events (MACE: cardiovascular death, myocardial infarction, stroke) in elderly patients with acute coronary syndrome (ACS)
To compare outcomes of patients aged ≥75 years with ACS (STEMI, NSTEMI, unstable angina) treated with percutaneous coronary intervention (PCI) versus conservative medical therapy. The primary outcome includes all-cause mortality and major adverse cardiovascular events (MACE). Unit of Measure: % of patients experiencing event.
Time frame: Peri-procedurally (within 48 hours of PCI or index admission for conservative therapy), at discharge (assessed up to 14 days after admission (Day 1)), and at 6 months after discharge (± 14 days).
Impact of treatment strategy (PCI vs conservative therapy) on hemorrhagic complications
Incidence of major bleeding, defined as clinically overt bleeding resulting in hemodynamic compromise, intracranial hemorrhage, bleeding requiring transfusion, or bleeding requiring surgical or endovascular hemostatic intervention; includes gastrointestinal and access-site bleeding. Unit of Measure: Incidence (%)
Time frame: Peri-procedurally (within 48 hours of PCI or index admission) and at discharge (assessed up to 14 days after admission (Day 1)).
Number of Participants with ≥1 All-cause Rehospitalization
Proportion of patients with ≥1 rehospitalization for any cause and total number of rehospitalizations per patient during follow-up; comparison between PCI and conservative therapy. Unit of Measure: % of patients with ≥1 rehospitalization; count per patient.
Time frame: 6 months after discharge (± 14 days).
Demographic predictors of conservative management
Patient age and sex as predictors of the decision to pursue conservative medical therapy instead of percutaneous coronary intervention (PCI). Independent predictors will be identified using multivariable logistic regression and reported as odds ratios with 95% confidence intervals. Measure: Age (years); Sex (male/female).
Time frame: Baseline (Day 1).
Admission hemoglobin as predictor of conservative management
Hemoglobin concentration measured at admission and recorded in the dataset. Evaluated as a predictor of conservative therapy versus PCI using multivariable logistic regression. Unit of Measure: g/L.
Time frame: Baseline.
Admission eGFR (CKD-EPI) as predictor of conservative management
Estimated glomerular filtration rate (CKD-EPI) measured at admission and recorded in the dataset. Evaluated as a predictor of conservative therapy versus PCI using multivariable logistic regression. Unit of Measure: mL/min/1.73 m².
Time frame: Baseline.
Admission hs-Troponin I as predictor of conservative management
High-sensitivity troponin I measured at admission; assay name and 99th percentile documented. Evaluated as a predictor of conservative therapy versus PCI using multivariable logistic regression. Unit of Measure: ng/L.
Time frame: Baseline.
Admission CRP as predictor of conservative management
C-reactive protein measured at admission and recorded in the dataset. Evaluated as a predictor of conservative therapy versus PCI using multivariable logistic regression. Unit of Measure: mg/L.
Time frame: Baseline.
Admission BNP/NT-proBNP as predictor of conservative management
BNP or NT-proBNP measured at admission and recorded in the dataset. Evaluated as a predictor of conservative therapy versus PCI using multivariable logistic regression. Unit of Measure: pg/mL.
Time frame: Baseline.
Admission HbA1c as predictor of conservative management
Glycated hemoglobin (HbA1c) measured at admission and recorded in the dataset. Evaluated as a predictor of conservative therapy versus PCI using multivariable logistic regression. Unit of Measure: %.
Time frame: Baseline.
Composite admission laboratory abnormality score as predictor of conservative management
Composite score derived from admission laboratory parameters not otherwise specified as individual outcomes. Included analytes: WBC with differential, RBC, HCT, MCV, MCH, MCHC, PLT, Glucose, urea, creatinine, total proteins, albumin, Total cholesterol, HDL, LDL, triglycerides, Na, K, Cl, Ca, AST, ALT, GGT, LDH, CK-MB, TSH. Each analyte will be coded as 1 if outside the central hospital laboratory reference range and 0 if within range (assay name, manufacturer, units, and reference intervals documented). The composite score equals the total number of abnormal parameters per patient and will be entered as a single predictor variable in multivariable logistic regression to evaluate its association with the decision for conservative therapy versus PCI. Missing data will be handled by multiple imputation; sensitivity analyses will assess robustness. Unit of Measure: Count (number of abnormal parameters per patient).
Time frame: Baseline.
ECG ischemic changes at admission as predictor of conservative management
Binary composite coded as 1 if any of the following are present on the admission ECG: ST elevation, ST depression, T-wave inversion, or pathologic q/Q/qS complexes; coded as 0 if none are present. Evaluated as a predictor of conservative therapy versus PCI in multivariable logistic regression. Unit of measure: Presence/absence (yes/no).
Time frame: Baseline
ECG rhythm and arrhythmias at admission as predictor of conservative management
Binary composite coded as 1 if any of the following are present on the admission ECG: atrial fibrillation (any), atrial flutter, supraventricular tachycardia, premature atrial complexes, premature ventricular complexes, non-sustained VT, sustained VT, ventricular fibrillation, or accelerated idioventricular rhythm; coded as 0 if none are present. Evaluated as a predictor of the decision for conservative therapy versus PCI. Unit of measure: Presence/absence (yes/no).
Time frame: Baseline.
ECG conduction abnormalities at admission as predictor of conservative management
Binary composite coded as 1 if any of the following are present on the admission ECG: sinoatrial block, sick sinus syndrome, atrioventricular block (any degree), right bundle branch block, left bundle branch block, left anterior hemiblock, or left posterior hemiblock; coded as 0 if none are present. Evaluated as a predictor of the decision for conservative therapy versus PCI.
Time frame: Baseline
Angiographic high-risk anatomy composite as predictor of conservative management
Binary composite coded as 1 if any of the following are present on coronary angiography prior to the treatment decision: left main coronary lesion (≥50% luminal stenosis), multivessel coronary disease (≥2 epicardial vessels with significant stenosis), bifurcation lesion, or ≥70% stenosis in any vessel; coded as 0 if none are present. Evaluated as a predictor of the decision to pursue conservative medical therapy versus PCI in multivariable logistic regression. Unit of measure: Presence/absence (yes/no).
Time frame: Peri-procedurally (immediately after angiography); values used are those available at or prior to the documented treatment decision (decision documented within 48 hours of admission).
Left Ventricular Ejection Fraction as predictor of conservative management
Categorical coded as 1 if LVEF ≤40%, coded as 2 if 41-49%, coded as 3 if ≥50%, based on Teichholz, Simpson biplane, or visual estimation if biplane unavailable. Evaluated as a predictor of conservative therapy versus PCI in multivariable logistic regression. Examinations will be performed using the GE Healthcare Vivid 6 ultrasound system (General Electric) in our central echocardiography laboratory, following standardized protocols.
Time frame: At admission (transthoracic echo within 72 hours of admission), values used are those available at or prior to the documented treatment decision.
E/e' ratio as predictor of conservative management
Binary composite coded as 1 if average E/e' ≥16, coded as 0 if \<16. Evaluated as a predictor of conservative therapy versus PCI in multivariable logistic regression. Examinations will be performed using the GE Healthcare Vivid 6 ultrasound system (General Electric) in our central echocardiography laboratory, following standardized protocols.
Time frame: At admission (transthoracic echo within 72 hours of admission), values used are those available at or prior to the documented treatment decision.
Pericardial effusion as predictor of conservative management
Binary coded as 1 if effusion present, coded as 0 if absent. Evaluated as a predictor of conservative therapy versus PCI in multivariable logistic regression. Examinations will be performed using the GE Healthcare Vivid 6 ultrasound system (General Electric) in our central echocardiography laboratory, following standardized protocols.
Time frame: At admission (transthoracic echo within 72 hours of admission), values used are those available at or prior to the documented treatment decision.
Left Atrial Volume Index as predictor of conservative management
Categorical coded as 1 if LAVI ≥34 mL/m², coded as 0 if \<34 mL/m². Evaluated as a predictor of conservative therapy versus PCI in multivariable logistic regression. Examinations will be performed using the GE Healthcare Vivid 6 ultrasound system (General Electric) in our central echocardiography laboratory, following standardized protocols.
Time frame: At admission (transthoracic echo within 72 hours of admission), values used are those available at or prior to the documented treatment decision.
Wall Motion Score Index as predictor of conservative management
Categorical coded as 1 if WMSI \>1.0, coded as 0 if ≤1.0. Evaluated as a predictor of conservative therapy versus PCI in multivariable logistic regression. Examinations will be performed using the GE Healthcare Vivid 6 ultrasound system (General Electric) in our central echocardiography laboratory, following standardized protocols.
Time frame: At admission (transthoracic echo within 72 hours of admission), values used are those available at or prior to the documented treatment decision.
Valvular regurgitation as predictor of conservative management
Binary composite coded as 1 if any of the following are present: aortic regurgitation, mitral regurgitation, pulmonary regurgitation, or tricuspid regurgitation; coded as 0 if none are present. Evaluated as a predictor of conservative therapy versus PCI in multivariable logistic regression. Examinations will be performed using the GE Healthcare Vivid 6 ultrasound system (General Electric) in our central echocardiography laboratory, following standardized protocols.
Time frame: At admission (transthoracic echo within 72 hours of admission), values used are those available at or prior to the documented treatment decision.
Comorbidity predictors of conservative management
Presence of predefined comorbid conditions recorded at admission and used as predictors of the decision for conservative therapy versus PCI. Each comorbidity will be recorded using standard clinical definitions and ICD codes where available. Comorbidities will be coded as binary variables (yes/no); chronic kidney disease will be classified by KDIGO stage (CKD stage 1-5). Candidate comorbid predictors will be evaluated in univariate analyses and included in multivariable logistic regression based on clinical relevance and univariate p\<0.10. Missing data will be handled by multiple imputation; sensitivity analyses will be performed.
Time frame: At admission (baseline, pre-intervention/decision).
Frailty predictors of conservative management
Frailty assessed at admission using the Rockwood Clinical Frailty Scale (CFS) and the Hopkins frailty instrument; assessor initials and assessment timing recorded. Scores modeled primarily as continuous and secondarily as prespecified categorical variables; inclusion in multivariable logistic regression guided by univariate screening and clinical relevance; missing data handled by multiple imputation. Measure: Rockwood CFS coded as: 0 (score 1-3); 1 (score 4-6); 2 (score 7-9). Hopkins frailty coded as: 0 (score 0); 1 (score 1-2); 2 (score 3-5). Raw Rockwood CFS (1-9) and raw Hopkins score (numeric) will be recorded.
Time frame: At admission (baseline, pre-intervention/decision).
Number of Participants with Major Adverse Cardiovascular Events (MACE)
Composite endpoint defined as cardiovascular death, myocardial infarction, or stroke. Participants will be coded as positive if any of these events occur, and negative if none occur. Unit of measure: Presence/absence (yes/no).
Time frame: Outcome assessed at discharge (up to 14 days after admission (Day 1)), and outcomes reassessed 6 months after discharge (± 14 days).
Number of Participants with Cardiovascular Rehospitalization
Presence/absence of rehospitalization due to cardiovascular causes (including acute coronary syndrome, heart failure, arrhythmia, stroke, or repeat revascularization). Unit of measure: Presence/absence (yes/no).
Time frame: Outcome assessed at discharge (up to 14 days after admission (Day 1)), and outcomes reassessed 6 months after discharge (± 14 days).
Number of Participants with All-cause Mortality
Presence/absence of death from any cause. Unit of measure: Presence/absence (yes/no).
Time frame: Outcome assessed at discharge (up to 14 days after admission (Day 1)), and outcomes reassessed 6 months after discharge (± 14 days).
Correlation between clinical predictors and clinical outcomes (in-hospital MACE and 6-month all-cause mortality)
The outcomes are in-hospital major adverse cardiovascular events (MACE: cardiovascular death, myocardial infarction, stroke) and all-cause mortality at 6 months. Each outcome will be reported separately. Candidate predictors include demographic characteristics, prespecified comorbidities, admission laboratory values (including renal function and eGFR), echocardiographic measures (e.g., LVEF, LV volumes, LAVI, TAPSE), ECG parameters (e.g., ST elevation/depression, T-wave inversion, rhythm abnormalities, conduction blocks), and angiographic findings (culprit vessel, multivessel disease, left main disease, percent stenosis). Independent predictors will be identified using multivariable logistic regression for in-hospital MACE and Cox proportional hazards models for 6-month mortality. Full variable definitions, units, assay names, and reference ranges are provided in the SAP.
Time frame: Predictors measured at admission (baseline). In-hospital MACE assessed during hospitalization (up to 15 days after admission). Six-month all-cause mortality assessed 6 months after discharge (±14 days).
Correlation between frailty scores and cognitive categories and clinical outcomes (in-hospital MACE and 6-month all-cause mortality).
Frailty and cognition will be assessed at admission using the Rockwood Clinical Frailty Scale (CFS, range 1-9; higher = greater frailty), the Hopkins frailty instrument (range 0-5; higher = greater frailty), and the Mini-Mental State Examination (MMSE, range 0-30; higher = better cognition). Clinical outcomes are in-hospital MACE (composite of cardiovascular death, myocardial infarction, and stroke) and all-cause mortality at 6 months. Results will be reported by the prespecified score categories (CFS 1-3 / 4-6 / 7-9; Hopkins 0 / 1-2 / 3-5; MMSE \<24 vs ≥24) and expressed as the percentage of patients with each outcome within categories. Statistical analysis will include correlation coefficients (Spearman or Pearson as appropriate) and multivariable models comparing categories (logistic regression for in-hospital MACE; Cox proportional hazards for 6-month mortality); reference groups, covariates and all cutoffs are specified in the SAP.
Time frame: Scores measured at admission, outcomes assessed at discharge (up to 14 days after admission), and outcomes reassessed 6 months after discharge (± 14 days).
Secondary complications and adverse events
Incidence of periprocedural complications, gastrointestinal bleeding, neurological complications, and psychiatric disorders (e.g., psycho-organic syndrome).
Time frame: Peri-procedurally, at discharge (assessed up to 14 days after admission (Day 1)), and at 6 months after discharge (± 14 days).
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