Physiology and Imaging Pre- and Post Stenting

Background

With the availability of drug-eluting stents for percutaneous coronary
intervention (PCI), the incidence of in-stent restenosis has importantly
decreased as compared with bare-metal stents. (1) However, the issue of (late)
stent thrombosis with drug-eluting stents (DES) is still under debate. (2) One
of the possible explanations for late stent thrombosis with DES is
underexpansion of the stent at the index procedure. (3) Newer, innovated types
of DES (like the Biomatrix* Flex biolimus eluting stent (BES) (Biosensors)) can
potentially lower major adverse cardiac event rates as compared to *older*
generation DES. However, correct selection of lesions to be stented still
remains important because even the newer generation drug-eluting stents carry
an intrinsic risk of stent-placement related periprocedural myocardial
infarction, in-stent restenosis and (late) stent thrombosis. By using
fractional flow reserve (FFR) to select ischemic lesions for stenting and
select non-ischemic lesions for medical therapy, outcome of PCI can be
improved, as shown by the FAME study. (4) PCI results might even be further
improved by the routine assessment of stent implantation results by
intracoronary imaging techniques like optical coherence tomography (OCT) and
intravascular ultrasound (IVUS). (5) Such techniques are able to assess stent
implantation results and reveal problems with potential clinical impact like
stent-edge dissection or stent underexpansion.
FFR is used in most PCI cases in our cath lab, based on results from large,
randomized trials like DEFER and FAME and the recently published European
Society of Cardiology guidelines on revascularization, in which FFR now has a
class I recommendation for lesion analysis pre-PCI. (6) OCT and IVUS are also
already integrated in daily practice in our cath labs. Both imaging modalities
are used to determine stent size or diameter pre-PCI in complex cases and
stenting results after PCI, but in general only when the operator doubts the
angiographic result.
The development of OCT provides new opportunities for the evaluation of
coronary stents. Having a much higher spatial resolution than IVUS, OCT is
currently used for long-term assessment of stent implantation. In the immediate
future, however, it is quite likely that OCT will be used to optimize stent
deployment, with an added value in contexts like ambiguous images presenting
after stenting, or in complex PCI procedures like bifurcation stenting.
In the literature not much is known about the combined use of FFR and OCT pre-
and post-stenting. There seems to be a potential complementary role of
physiological and anatomical assessment to guide decision making in complex
clinical scenarios.
Combining these two modalities might even further improve PCI results. FFR has
shown to significantly decrease major adverse cardiac event (MACE)-rates when
used to determine which lesions are to be stented and which are not. OCT is
promising in the assessment of stent implantation, however little is known
about the impact of OCT on the frequency of treatment strategy change (like
postdilatation of a stent) after stent implantation and subsequent impact on
outcome.
The primary goal of the PIPPS study (a prospective, non-randomized study) is to
detect in what percentage of lesions OCT and/or FFR post-PCI change
post-stenting treatment (additional post-dilatation, ic/iv 2B3A treatment)
compared to a regular post-stenting assessment based on angiography? If the
PIPPS study detects a clinically relevant difference between both strategies,
it creates a basis for future randomized trial(s) comparing both PCI-strategies
(PCI with versus without intravascular imaging) with respect to clinical
outcome.
In order to avoid potential bias in the PIPPS study due to usage of different
types of second generation DES, a single, frequently used in our cath lab, type
of second generation DES is used in this study (in casu: Biomatrix* Flex
biolimus eluting stent (BES) (Biosensors)).

Objectives of this study

1. In what percentage of lesions do OCT and/or FFR post-PCI change
post-stenting treatment (additional post-dilatation, ic/iv 2B3A treatment)
compared to a regular post-stenting assessment based on angiography?

2. Do OCT and/or FFR (in what percentage of lesions) change the choice of
stent-size (diameter and length) pre-PCI, compared to a regular sizing stragegy
based on angiography?


3. Sub-objectives:
- In what percentage of lesions that receive additional treatment, based on
OCT, does the OCT images improve after additional treatment (disappearing of in
stent dissection or protrusion or malapposition after post-dilatation etc.)?

Design of the study
Stepwise:
1 - Signed informed consent?
2 - Angiography
2 - Still fulfilling in- exclusion criteria?
3 - What would stent length/diameter choice be based on angiogram? Length and
diameter fulfilled in file with time registration.
4 - FFR (+pullback) and OCT pre-PCI. What would stent length/diameter choice be
based after these measurements?
Length and diameter fulfilled in file with time registration. OCT file and FFR
curve file recorded for off-line analysis.
6 - Actual chosen (by operator) length and diameter fulfillled in file with
time registration.
7 - PCI according to local, routine practice.
8 - Angiography post-PCI.
9 - What is the opinion of the operator about the stenting-result based on the
angiogram? Any signs of dissection, trombus, malapposition etc? Additional
treatment needed? If so, what treatment, based on the angiogram? These items
are fulfilled in file with time registration.
10 - FFR (+pullback) and OCT post-PCI. Any signs of dissection, trombus,
malapposition etc by OCT? Additional treatment needed? If so, what treatment,
based on the FFR/OCT tracings? These items are fulfilled in file with time
registration.
OCT file and FFR curve file recorded for off-line analysis.
1 1- Registration of any additional treatment (post-dilatation, 2B3A etc) and
registration of any lesion-related event.
12 - Recommended to perform FFR (+pullback) and OCT after each additional
treatment.
13 - Repeat steps 2-12 for additional lesions.
14 * Post-PCI in-hospital cardiac enzymes according to local routine practice.
Registration of in-hospital patient-related events.

NA