BVS-OCT Imaging Study

I. INTRODUCTION Bioabsorbable drug-eluting scaffolds ("BVS") have emerged as a potential
major breakthrough for treatment of coronary artery lesions providing a possibility to
overcome the long term limitations of conventional stent implantation which precludes future
surgical revascularization, eliminates reactive vasomotion, impairs noninvasive imaging and
exposes patients to the risk of very late stent thrombosis. BVS have been extensively studied
in clinical trials. Treatment of noncomplex obstructive coronary artery disease with BVS was
within the prespecified margin for noninferiority compared to Xience stent with respect to
target lesion failure at 1 year in the latest large-scale randomized trial (ABRORB III).
Although the concept of self-degrading stent is attractive and the results from clinical
trials have been promising, there is a paucity of data regarding the use of BVS in "real
world" patients undergoing percutaneous intervention ("PCI"). The outcomes from a large BVS
registry of patients with relatively unselected clinical characteristics and lesions were
comparable to those reported for the second generation drug eluting stents ("DES"), however,
the scaffold thrombosis rate in the first 30 days after implantation resembled that of the
first generation DES suggesting that the lesion selection and procedure optimization require
further improvement. BVS development has required new imaging modalities, assessment
methodologies, and treatment strategies because their design, degradation rate, coating,
changes in mechanical properties may affect safety and efficacy of the device. Due to its
high resolution, Optical Coherence Tomography ("OCT") imaging has played a central role in
understanding the short and long term performance of bioresorbable scaffolds.

II. STUDY AIM To evaluate the acute and long term outcomes of BVS implantation in consecutive
coronary artery disease ("CAD") patients using OCT imaging.

III. STUDY POPULATION Fifty (50) consecutive patients who underwent PCI with BVS implantation
and OCT imaging for treatment of CAD.

IV. STUDY DESIGN This is a single center retrospective analysis of data collected under the
EXEMPT database (GCO# 02-0178) at the Cardiac Catheterization Laboratory at Mt. Sinai
Hospital.

V. STUDY PROCEDURES Patients with stable CAD who underwent PCI with BVS implantation. Lesions
were treated with pre-dilatation using conventional semicompliant or non-compliant balloon.
The use of additional devices, cutting balloons or rotablator, were performed at the
operator's discretion. The operator made the decision on BVS length and size. First OCT
pullback (OCT-PRE) was performed before BVS implantation to analyze lesion stenosis,
references, and plaque morphology including the extent and location of calcification. In
addition, online co-registration of OCT with coronary angiogram was performed to confirm the
correct spatial orientation of OCT findings. The second OCT pullback (OCT - POST) was
performed after BVS implantation followed by post-dilatation (20 atm). Angio-OCT
co-registration was used to assess acute post-procedural results.

VI. STUDY OUTCOMES

- Acute lumen gain after BVS implantation by quantitative coronary angiography ("QCA") and
OCT; effect of coronary calcification on lumen gain, BVS apposition and expansion.

- Review of the clinical follow up data which was collected at 1 month and 12 months after
the procedure

VII. IMAGE ANALYSIS

QCA analysis. In each patient, the treated segment (in-scaffold) and the peri-scaffold
segment (defined as 5 mm proximal and distal to the scaffold edge) will be analyzed by QCA in
paired matched angiographic views before and after procedure using metallic markers at the
proximal and distal ends of the device. Minimal lumen diameter (MLD), reference vessel
diameter, percentage of area stenosis, and lesion length will be measured by two experienced
analysts using dedicated software (QCA-QAngioXA 7.3; Medis) as previously described. Acute
lumenal gain will be defined as the difference between MLD immediately after procedure and
MLD before BVS implantation. In addition, the presence of angiographic calcification will be
assessed. Calcification will be identified by angiography as readily apparent radiopacities
within the vascular wall at the site of stenosis and will be classified as none/mild or
moderate (radiopacities noted only during the cardiac cycle before contrast injection)/severe
(radiopacities visible without cardiac motion before contrast injection usually compromising
both sides of the lumen).

OCT lesion analysis will be performed offline at 1-mm interval according to previously
validated criteria and as we previously described. The minimal and reference lumen diameter
and area will be measured to calculate percent lumen area stenosis. Plaques will be
classified as fibrous, lipid, or calcified. For each lipid plaque, the maximal lipid arc will
be measured at 1-mm interval and the minimal thickness of the fibrous cap will be assessed.
The degree of circumferential extent of calcification will be quantified at 1 mm interval by
measuring the maximal calcification arc.

OCT analysis of BVS will be performed at 1-mm interval within the entire stented segment and
at 5 mm proximal and distal to the BVS edge. For each cross section analyzed, the area, mean,
minimal and maximal diameters of the BVS will be measured automatically with manual
corrections if appropriate. The proximal and distal reference vessel area (RVA) will be
calculated as the mean of the largest two lumenal areas 5 mm distal and proximal to the BVS
edge. Acute strut fracture will be suspected if isolated struts are detected lying unopposed
in the lumen with no connection to other surrounding stent struts. 3D OCT reconstruction with
QAngio OCT RE software (Medis) will be performed to confirm the diagnosis. Incomplete strut
apposition (ISA) will be defined as the presence of struts separated from the underlying
vessel wall. The percentage of ISA will be calculated as a ratio of malapposed struts number
to the total number of struts observed at 1-mm interval. Since abluminal border of the struts
can be visualized in BVS, we will assess the ISA area for each frame with malapposed struts.
The percentage of Residual Area Stenosis (RAS) will be calculated as: [(1 - (minimal lumen
area/RVA))] ×50 ; the eccentricity index as the ratio between the minimal and the maximal
diameter. The symmetry index will be defined as (maximal stent diameter - minimal stent
diameter)/(maximal stent diameter). OCT analysis will be performed in Mount Sinai Cath Lab
Core imaging laboratory.

VIII. PROPENSITY-MATCHED COMPARISON BETWEEN BVS AND DES A retrospective analysis will be
performed on 50 study patients who underwent PCI with BVS and consecutive patients who
underwent DES implantation in Mount Sinai catheterization laboratory with the comparator
sample size of 50. The DES patients will be selected from the Mount Sinai imaging database.
Propensity score matching will be performed to reduce the effect of confounding factors in
the retrospective study for two groups of patients with different recruitment periods.
Multiple logistic regression analysis will include the following variables as covariates:
previous MI, previous CABG, CAD family history, history of smoking, dyslipidemia, diabetes
mellitus, use of atherectomy device, stent/BVS post-dilatation, stent/BVS diameter and
length, maximal calcium arc by OCT and total number of treated vessels.

Inclusion Criteria:

- Consecutive patients who underwent PCI with BVS implantation and OCT imaging for
treatment of CAD

Exclusion Criteria: