To determine factors associated with repeat revascularization among adults aged 25 years and above within 5 years of first Percutaneous Coronary Intervention (PCI) at a tertiary care hospital.

Matched case-control study design was employed to determine the association between re-peat revascularization and its determinants in patients within 5 years of undergoing index PCI. The case was defined as a patient who had undergone repeat revascularization within 5 years of undergoing index PCI. Control was defined as a patient who had not undergone repeat revascularization within 5 years of undergoing index PCI.

The retrospective study was carried out with the approval of the Ethical Review Committee of the tertiary care hospital where the study was carried out. A waiver of informed consent was granted as this was a retrospective study and all patients were discharged from the hospital.

A minimum of 120 cases with matched 240 controls were required in 1:2 case to control ratio. This sample size was essential to achieve the power of 80% for an anticipated matched odds ratio of 2 with the hypothesized correlation of 0.2 using a two-sided hypothesis test with a significance level of 0.05.

The outcome of the study was the Repeat revascularization status. There are different types of repeat revascularization according to the site and lesion to which intervention has been provided. Any type of repeat revascularization was considered and enrolled as a case in this study5.

Covariates included in the study were divided into patient characteristics (gender, age, health coverage, BMI, smoking status), comorbidity status (Hypertension, Diabetes Mellitus, Hyperlipidaemia, valvular disease), clinical characteristics (Creatinine level, Systolic Blood Pressure, Diastolic Blood Pressure, HbA1c, Cholesterol level, other technical factors related to the index PCI) and medication status (Beta-blocker, ACE Inhibitor, Statin).

Inclusion Criteria for Cases:

• Aged 25 years and older
• Undergone repeat revascularization within 5 years of undergoing index PCI (from 2011 to 2017).

Exclusion Criteria for Cases:

• If suffering from any hypercoagulable disorder
• Revascularization procedure was per-formed outside the study setting
• Staged PCI within 3 weeks or planned PCI within 6 months of Index PCI.

Inclusion Criteria for Controls:

• Patients aged 25 years and older
• Undergone PCI once from the year 2011 to 2017.

Exclusion Criteria for Controls:

• If suffering from any hypercoagulable disorder.

The target population includes all the adult patients age 25 years and above who were revascularized at least at the Aga Khan University Hospital, Karachi.