2.1

Study design

It was a retrospective, nonrandomized comparative single-centre observational study conducted in a tertiary care private hospital between January 2014 and December 2014. The study design was approved by the institutional ethics committee. The written consent was taken from all patients included in this study.

2.2

Study patients

All consecutive patients with very long segment type C ACC/AHA de novo coronary artery stenosis (>30 mm) detected following coronary angiogram were included in this study.

2.3

Procedure and adjunct pharmacotherapy

Patients who met the inclusion and exclusion criteria after diagnostic angiography and received treatment with R-ZES or X-EES were compared. Stent implantation was performed according to standard techniques . For this study, R-ZES were available in diameters of 2.5, 2.75, 3.0, 3.5, and 4.0 mm and in lengths of 34 and 38 mm; X-EES were available in diameters of 2.5, 2.75, 3.0, 3.5, and 4.0 mm and in lengths of 33, 38, 48 mm. Those patients who received more than one >30-mm length stent for full lesion coverage for any single vessel or multiple vessels and fulfilled the inclusion and exclusion criteria enrolled in this study.

Before or during the procedure, all patients received at least 300 mg of aspirin and standard loading dose of any of these three P2Y12 inhibitors (clopidogrel/prasugrel/ticagrelor). Heparin was administered throughout the procedure to maintain an activated clotting time ≥250 s. Administration of glycoprotein IIb/IIIa inhibitors was at the discretion of the operator. After the procedure, all patients received 75–150 mg/day of aspirin indefinitely, as well as maintainance dose of clopidogrel/prasugrel/ticagrelor for at least 12 months .

Intravascular ultrasound (IVUS) or optical coherence tomography (OCT) was performed using standard technique as described previously as per discretion of the operator.

2.4

Study end points

The primary end point of this study was to evaluate target lesion failure (TLF) and the secondary end point was to look for immediate procedural success which is a composite of major adverse cardiac events (ie. death, target lesion myocardial infarction, stent thrombosis or target lesion revascularization) within 12 months.

All deaths were considered to be of cardiac causes unless a noncardiac cause could be identified. A diagnosis of myocardial infarction was based on the presence of new Q waves in at least 2 contiguous leads on an ECG or an elevation of creatine kinase-MB fraction or troponin I concentration >3 times the normal upper limit in at least 2 blood samples . Repeat coronary angiogram was advised if ischemic signs (ie, positive treadmill tests) or symptoms were present. Revascularization of the target lesion and vessel was considered if there was ≥70% stenosis of the diameter of the treated lesion or vessel by coronary angiogram. Stent thrombosis was defined as definite or probable by Academic Research Consortium definitions . Device success was defined as a final stenosis of <30% of the vessel diameter after implantation of the assigned stent only .

2.5

Follow-up

Clinical follow-up visits were scheduled at 30 days, 3 months, 6 months and 12 months. We monitored clinical status, rehospitalisation, re-catheterization, cardiac-related medications, and occurrence of major adverse cardiac events throughout follow-up. Repeat coronary angiogram was advised only in symptomatic patients.

2.6

Statistical analysis

For the present analyses, individual data were pooled on a patient-level basis. Continuous variables are expressed as mean ± SD, and categorical variables are presented as absolute number and proportion (%). Overall comparisons between nonmatched groups were performed by the t test for continuous variables and by chi-square for categorical variables. Propensity score matching was applied to compare the 1-year device-oriented TLF for patients treated with R-ZES and those treated with X-EES. A propensity score matching was performed using a proprietary macro developed and tested for SPSS version 20.0 (SPSS Inc., Chicago, IL, USA). First, the program performed a logistic regression to score all patients according to the treatment (R-ZES vs X-EES), using as covariates clinical and procedural parameters that were clinically relevant for the end point: age (years), sex (male/female), diabetes mellitus (yes/no), and culprit vessel and stent/scaffold length and diameter (mm). Second, the macro searched and selected the best match case of the X-EES group for every R-ZES case according to the absolute value of the difference between the propensity score of X-EES and R-ZES cases under consideration. Analyses were then performed between R-ZES and X-EES, stratified by pairs to account for propensity score matching. A Cox regression model was developed to adjust the TLF between the R-ZES and X-EES for use of GP IIb/IIIa inhibitors (yes/no) and use of clopidogrel vs other platelet inhibitors (ticagrelor/prasugrel). A p value <0.05 was considered statistically significant. All statistical analyses were performed using SPSS version 20.0.

2.1

Study design

It was a retrospective, nonrandomized comparative single-centre observational study conducted in a tertiary care private hospital between January 2014 and December 2014. The study design was approved by the institutional ethics committee. The written consent was taken from all patients included in this study.

2.2

Study patients

All consecutive patients with very long segment type C ACC/AHA de novo coronary artery stenosis (>30 mm) detected following coronary angiogram were included in this study.

2.3

Procedure and adjunct pharmacotherapy

Patients who met the inclusion and exclusion criteria after diagnostic angiography and received treatment with R-ZES or X-EES were compared. Stent implantation was performed according to standard techniques . For this study, R-ZES were available in diameters of 2.5, 2.75, 3.0, 3.5, and 4.0 mm and in lengths of 34 and 38 mm; X-EES were available in diameters of 2.5, 2.75, 3.0, 3.5, and 4.0 mm and in lengths of 33, 38, 48 mm. Those patients who received more than one >30-mm length stent for full lesion coverage for any single vessel or multiple vessels and fulfilled the inclusion and exclusion criteria enrolled in this study.

Before or during the procedure, all patients received at least 300 mg of aspirin and standard loading dose of any of these three P2Y12 inhibitors (clopidogrel/prasugrel/ticagrelor). Heparin was administered throughout the procedure to maintain an activated clotting time ≥250 s. Administration of glycoprotein IIb/IIIa inhibitors was at the discretion of the operator. After the procedure, all patients received 75–150 mg/day of aspirin indefinitely, as well as maintainance dose of clopidogrel/prasugrel/ticagrelor for at least 12 months .

Intravascular ultrasound (IVUS) or optical coherence tomography (OCT) was performed using standard technique as described previously as per discretion of the operator.

2.4

Study end points

The primary end point of this study was to evaluate target lesion failure (TLF) and the secondary end point was to look for immediate procedural success which is a composite of major adverse cardiac events (ie. death, target lesion myocardial infarction, stent thrombosis or target lesion revascularization) within 12 months.

All deaths were considered to be of cardiac causes unless a noncardiac cause could be identified. A diagnosis of myocardial infarction was based on the presence of new Q waves in at least 2 contiguous leads on an ECG or an elevation of creatine kinase-MB fraction or troponin I concentration >3 times the normal upper limit in at least 2 blood samples . Repeat coronary angiogram was advised if ischemic signs (ie, positive treadmill tests) or symptoms were present. Revascularization of the target lesion and vessel was considered if there was ≥70% stenosis of the diameter of the treated lesion or vessel by coronary angiogram. Stent thrombosis was defined as definite or probable by Academic Research Consortium definitions . Device success was defined as a final stenosis of <30% of the vessel diameter after implantation of the assigned stent only .

2.5

Follow-up

Clinical follow-up visits were scheduled at 30 days, 3 months, 6 months and 12 months. We monitored clinical status, rehospitalisation, re-catheterization, cardiac-related medications, and occurrence of major adverse cardiac events throughout follow-up. Repeat coronary angiogram was advised only in symptomatic patients.

2.6

Statistical analysis

For the present analyses, individual data were pooled on a patient-level basis. Continuous variables are expressed as mean ± SD, and categorical variables are presented as absolute number and proportion (%). Overall comparisons between nonmatched groups were performed by the t test for continuous variables and by chi-square for categorical variables. Propensity score matching was applied to compare the 1-year device-oriented TLF for patients treated with R-ZES and those treated with X-EES. A propensity score matching was performed using a proprietary macro developed and tested for SPSS version 20.0 (SPSS Inc., Chicago, IL, USA). First, the program performed a logistic regression to score all patients according to the treatment (R-ZES vs X-EES), using as covariates clinical and procedural parameters that were clinically relevant for the end point: age (years), sex (male/female), diabetes mellitus (yes/no), and culprit vessel and stent/scaffold length and diameter (mm). Second, the macro searched and selected the best match case of the X-EES group for every R-ZES case according to the absolute value of the difference between the propensity score of X-EES and R-ZES cases under consideration. Analyses were then performed between R-ZES and X-EES, stratified by pairs to account for propensity score matching. A Cox regression model was developed to adjust the TLF between the R-ZES and X-EES for use of GP IIb/IIIa inhibitors (yes/no) and use of clopidogrel vs other platelet inhibitors (ticagrelor/prasugrel). A p value <0.05 was considered statistically significant. All statistical analyses were performed using SPSS version 20.0.