Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3840_Библиотеки_им_академика_М_И_Перельмана
.pdf
68
LIM AND KOO
the FFR-guided decision-making approachto stenting (i.e., stents only placed in lesions with an
FFR <0.80)ascompared toan approach relyingonly onangiography (i.e.,stents placed in lesions
with a >50% stenosis). After one year of follow-up, the FFR-guided group had a significantly
lower MACE rate. Thus, even in complex patients, FFR can be used to direct decision making
in the cath lab.
Besides confirmingprevious studies showing low subsequentevent rates in thosepatients
in whom PCI was not performed, the FAME study gave considerable credence for defining
the ischemic threshold for performing PCI as an FFR of 0.80 or less. Previous to this study,
validation studieshad shown thata value of 0.75 was highlycorrelative with ischemiadetection
in noninvasive studies, but there was a “gray-zone” that allowed for ischemia to be present up
to an FFR of 0.80 if the patient had significant left ventricular hypertrophy. FAME has shown
that an operator can implement an FFR ischemic cut-off of 0.80 to ensure that no false-negative
FFR lesions are undetected and still have a dataset supporting excellent clinical outcomes. That
being said, the best pure cut-off value to correlate with an ischemic-producing lesion remains
an FFR <0.75.
DETERMINING THE SIGNIFICANCE OF SB OSTIAL LESIONS
The precise determination of ostial lesion severity by angiography has proven to be difficult
due to angulation, branch overlap, and imaging artifacts. This difficulty is demonstrated by the
need for additional angulated radiographic views, and at times, cannot be resolved despite the
angiographer’s best efforts. Fundamentally, angiographic guidance for percutaneous treatment
of a bifurcation involves at least the ostium of the SB and, in the case of a distal left main, the
ostia of the LAD and LCx.
Studies have also evaluated the utility of intravascular ultrasound (IVUS) to help guide
decision making in the cath lab. Given the previously stated limitations of the ability to fully
visualize bifurcation lesions with angiography alone it is not surprising that IVUS has proven
useful in providing high-quality quantitative and qualitative measures of plaque burden at
bifurcation lesions. A recent case series showed that the extent of plaque burden at the SB
ostium (as determined by IVUS) predicts the incidence of SB closure as compared to those
bifurcations in which the plaque was exclusively in the MV (6). This finding suggests that if the
operator suspects a high probability that the SB will eventually require stenting anyway, then
why not elect for a two-stent strategy at the start?
Diverting from the provisionalSB stent approach could beconsidered if thepatient would
be left with significant angina following the procedure. Although IVUS can show the location
of plaque, its ability to assess the physiologic significance of the plaque has only been shown in
the proximal or mid segments of main epicardial vessels (7). Furthermore, seeing larger plaque
burdens within the coronary tree before stenting a bifurcation lesion may prompt more operators to utilize a dual-stenting approach and increase the overall complexity of the procedure.
Increasing the complexity ofan intervention would be warrantedif provento provideimproved
outcomes, and as discussed in other chapters of this text, this is yet to be proven.
Physiologic assessment of the SB with FFR would alert the operator to the presence of an
ischemia causing SB lesion and potentially influence the treatment by preferentially utilizing
a two-stent strategy, especially when there appears to be angiographic disease in the SB. We
have previously shown (8) that the angiographic specificity is quite poor in predicting the
significance of ostial SBlesions as comparedto FFR. These data showed that ostialangiographic
lesions of less than 70% were never associated with an ischemic FFR. For those ostial lesions of
70% or greater, 20% were associated with a physiologically significant lesion which would be
responsible for ischemia. Prebifurcation assessment in this manner may allow the operator to
maximize the opportunity to treat bifurcations with a provisional strategy.
FFR UTILITY IN ASSESSING THE NEED TO TREAT AN OSTIAL SB LESION
A 64-year-old woman presents to the hospital with recurrent atypical chest discomfort. She has
a nondiagnostic electrocardiogram,showing no T-wave or ST-segment abnormalities consistent
with ischemia, and has negative troponins. She undergoes an adenosine perfusion stress test
that revealed normal left ventricular function and a small, mild anterior reversible perfusion
PHYSIOLOGIC GUIDANCE OF PROVISIONAL STENTING IN CORONARY BIFURCATION LESIONS
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
(A) (B)
Figure 1 Coronary angiography in the RAO caudal (A) and LAO (B) projections demonstrating a lesion in the
ostium of the circumflex coronary artery.
69
defect consistent with ischemia. She then underwent diagnostic angiography to evaluate her
coronary anatomy. Angiograms [Fig. 1(A) and 1(B)] showed no angiographic stenoses within
the LAD or RCA, but suggested a narrowing in the ostium of the circumflex. Although the
patient does have atypical chest discomfort and, at worst, single-vessel disease, the question of
whether this lesion is responsible for her symptoms remains unclear. To answer this question,
FFR was performed by advancing a pressure wire into the circumflex through a guide catheter
after intravenous anticoagulation was given. Intravenous adenosine (140 g/kg/min IV) was
infused and the FFR of the circumflex was found to be 0.89. This value is clearly above the
ischemic threshold and, thus, the lesion was left untreated and the patient was discharged.
FFR-Guided Provisional Stenting: Why This Approach Should Be Routinely Used?
A provisional stent strategy remains the preferable approach for most patients with bifurcation
lesions who are similar to those enrolled in the clinical trials (patients with moderate and focal
lesions in the SB ostium). However, the steps that follow the placement of the stent in the MV
are not universally agreed upon. Basically, the operator must make a decision regarding the
need for dilation of the ostium of the SB and, subsequently, whether the SB needs to be stented.
This decision process revolves around whether the ostium of the SB is compromised, much like
the discussion in the previous section. The operator relies on the angiogram of the bifurcation
to make this decision, but the angiographic ability to define significance of an obstruction in a
“jailed” SB is more challenging because the metal stent struts provide more distortion to the
picture.
This decision appears strikingly similar to the discussion of the significance of an ostial
SB—one in which the angiogram was not ashelpful asone wouldwant. Furthermore,the overall
goal for treating the patient remains the same: to abolish all coronary stenoses responsible for
ischemia. Thus, it is only logical that FFR could be utilized at this step to guide further therapy
or allow the operator to end the procedure with confidence.
The bestcollection of datato support theassessment of FFRin “jailed” SBsis that collected
by Koo et al. (9). In a group of 94 “jailed” SBs, FFR was measured and compared to quantitative coronary angiographic assessment of the SB. Although there was a significant correlation
between these two parameters (r =−0.41, p < 0.001), the variability of the points suggests little
accuracy of QCA to predict a positive FFR (Fig. 2). Of those lesions that were 90% or greater,
only 14 out of 25 had FFR values <0.75, demonstrating the inability of angiography to predict
“jailed” SB lesion severity.
70
1.0
.9
LIM AND KOO
r = −0.41
p < 0.001
.8
.7
Fractional flow reserve
.6
.5
40
50 60 70
80 90 100
Percent stenosis (%)
Figure 2 Correlation between fractional flow reserve and angiographic lesion severity of the jailed side branch.
Source
: Adapted from Ref. 9.
The true mark of a useful strategy in coronary intervention, however, is not whether a
lesion is physiologically or angiographically significant, but whether the clinical outcome is
acceptable for a given strategy. The same group evaluated a strategy of MV stenting followed
by assessment of the “jailed” SB by FFR (10). The SB was subsequently treated if an abnormal
FFR (<0.75)was found. Ninety-one patients with bifurcation lesions were treated in this manner
and then followed forsix months. Only 30%of all “jailed” SB lesions were foundto have an FFR
<0.75 in this patient population with 96% of all SBs able to be accessed successfully with the
pressure wire. The SB lesions that had an FFR <0.75 underwent further therapy with “kissing”
balloon angioplasty, resulting in a follow-up FFR of these SBs >0.75 in 92% of them. Six-month
follow-up in these patients found a 48% binary restenosis (defined as angiographic stenosis
>75%) of the SBs. However, when these stenoses were assessed by FFR, only 8% had a value
less than 0.75. Furthermore, TVR was only required in 5 of these 91 patients over the follow-up
period.
These data repeatedly demonstrate that angiography tends to overestimate the degree
of stenosis present in ostial SB lesions. When further therapy of the SB is restricted to those
patients with physiologically significant SB narrowing after MV stenting, excellent clinical
outcomes are achieved. Thus, FFR-guided decision making regarding further treatment of the
SB after the placement of an MV stent simplifies not only the decision-making process but also
the interventional procedure for the patient while providing excellent discriminatory capability
of FFR-guided provisional stenting.
Limitations to Generalizability
Although the use of FFR-guided decision making in treatment of bifurcation lesions is theoretically appealing, there are two issues that need to be addressed before this approach can be
recommended for routine use:
1. Is the current FFR wire technology versatile enough to be used successfully in the majority
of unselected patients with jailed SBs?
Although Koo and colleagues (9)have reported a success rate of 97% in crossing jailed
SBs with the FFR wire, patients in this study may represent a lower level of bifurcation
lesions complexity. This is confirmed by the fact that two-third of patients in this report
had a class (1–2) bifurcation morphology and the SB ostial lesions were focal (mean length
PHYSIOLOGIC GUIDANCE OF PROVISIONAL STENTING IN CORONARY BIFURCATION LESIONS
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
71
6 mm) and only of moderate severity (%DS = 45%). Success in wiring these lesions cannot
be generalized to more severe lesions with more complex morphology.
2. Is the clinical outcome of patients undergoing FFR-guided provisional stenting better than
that of patients undergoing angiography-guided provisional stenting?
Although the FAME study demonstrated that FFR-guided multivessel intervention is
superior to angiography-guidedmultivessel intervention, this data cannot be automatically
generalized to intervention on side branches. The current data certainly does not support
this generalization. In the first report by Koo et al. (9), there was no comparative control
arm. In the second Koo report the outcome of patients undergoing FFR-guided provisional
stenting was not better than a historical group of patients who underwent angiographyguided provisional stenting (10). Moreover, the NORDIC study, which included similar
patients to the study by Koo (i.e., bifurcations with moderate and focal disease in the
side branches), showed very low rate of crossover to stenting in the angiography-guided
provisional stenting arm and equivalent outcome to double stenting.
On the basis of these data, how canwe justify adding thetime andthe cost of usingFFR to
guide provisional stenting without proving that it provides superior outcome to angiographicguided provisional stenting? Until a randomized trial proves this point, this approach should
only be used selectively.
CASE EXAMPLES
Case #1
A 58-year-old man presents to the catheterization lab after being admitted to the hospital with
unstable angina.He undergoesa precatheterization stress test, which showedanterior ischemia,
and was found to have an LAD lesion, which was deemed to be significant [Fig. 3(A)].The LAD
is treated with a stent, “jailing” the diagonal branch that arises in the same region as the lesion.
After the stent was placed, routine angiography shows a “pinch” to the ostium of the diagonal
branch [Fig. 3(B)]. The operators weigh the option of wiring the diagonal and performing kissing
balloon angioplastybut instead, optto wire thediagonal with apressure wireand measure FFR.
Figure 3 (A) Coronary angiographyin the RAO cranialprojection showinga significantlesion in the LAD involving
a diagonal branch. (B) Coronary angiography following stent placement in the LAD showing impingement of the
diagonal branch.
(B)(A)
72
LIM AND KOO
With intravenous adenosine hyperemia, the FFR of the diagonal branch was 0.85. The operators
then removed the wires, and the patient was sent back to the floor without further angioplasty.
Case #2
A 70-year-old man undergoes diagnostic angiography secondary to unstable angina. He is
found to have serial lesions in his LAD, one before and one after a sizeable diagonal branch
[Fig. 4(A)]. Baseline FFR is performed in the LAD and diagonal to getmore data for planning of
the interventional strategy, and it is found that the FFR in the LAD is 0.71 and in the diagonal it
is 0.78. This FFR data indicates that the two serial lesions in the LAD are in fact physiologically
significant (FFR = 0.71). However, the diagonal FFR of 0.78 is most likely reflective of the LAD
lesion prior to the take-off of the branch and, therefore, the operator elects to stent the LAD
with a long stent covering both lesions and “jailing” the diagonal (this stent is deployed over
(B)(A)
(D)(C)
Figure 4 (A) Coronary angiography in the RAO cranial projection demonstrating serial LAD lesions before and
after a large diagonal branch. (B and C) Follow-up angiography in the RAO and LAO projections, showing that the
diagonal branch has an angiographic “pinch” after it is jailed and a pressure wire in the diagonal. (D) Final RAO
angiography.
PHYSIOLOGIC GUIDANCE OF PROVISIONAL STENTING IN CORONARY BIFURCATION LESIONS
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
73
the pressure wire used to FFR the LAD). Subsequent angiography demonstrates a “pinch” in
the ostial diagonal that did not seem to be present prior to the stent placement [Fig. 4(B)].
Repeat FFR assessment [Fig. 4(C)] is performed by advancing a pressure wire through the LAD
stent struts and into the diagonal. With adenosine-induced hyperemia, the diagonal FFR is
0.71. The LAD–diagonal bifurcation is then treated with the inflation of balloons in a “kissing”
fashion over the two pressure wires that are in the LAD and diagonal. Follow-up FFR is then
performed in the LAD (0.87) and the diagonal (0.83) and proves that there is no physiologically
significant obstruction to coronary blood flow left at the site [Figure 4(D) shows the final
angiogram]. This case shows not only the ability of the ostial “pinch” seen on the post-stent
angiogram to sometimes be physiologically significant, but also the ability for an operator to
perform a bifurcation procedure working over the coronary pressure wire (in this case, two
pressure wires). Of note, however, because of the pressure sensor housed within the wire and
the hydrophilic coating that is now on the shaft of commercially available pressure wires, it is
not recommended to entrap one ofthese wires left in aside branch with a mainbranch stent. The
preferred technique would be to leave a workhorse wire in the branch instead of the pressure
wire or to remove the pressure wire before deploying the main branch stent.
One may ask about finishing the case with a diagonal FFR of only 0.83? While this value
represents that there indeed is a residual stenosis within the diagonal branch, it is above the
ischemic threshold and, therefore, should not result in symptoms for the patient. However,
operators are acutely aware of the potential for restenosis of the ostial side branch, especially
when it has beentreated by a balloon inflation.So, is the likelihoodof restenosis of this diagonal
branch higher with an FFR of 0.83 than it would be if the value was greater or the side branch
was stented? There is no available data to answer this question and it becomes an operator
decision, weighing the increased complexity of a two-stent procedure with the available data
supporting the benefit of stenting the side branch.
Case #3
A 73-year-old woman is found to have a lesion in her circumflex, just after a large OM branch
[Fig. 5(A)]. FFR assessment of the OM branch was performed initially, indicating that there was
no baseline physiologic gradient (FFR =0.98). The LCx wasthen wired and stented in a manner
that “jailed” the large OM branch [Fig. 5(B)]. The OM branch was then rewired with theoriginal
pressure wire (which was removed while the LCx was treated) and FFR was measured and
found to be 0.98, identical to the baseline value. No further treatment was performed, and the
final angiogram is shown in Figure 5(C). This case demonstrates that the plaque burden in this
bifurcation was likely confined distal to the OM branch and the stenting of this vessel did not
change the geometry of the OM take-off enough to cause any physiologic affect on blood flow.
In our experience,it is an extremely rare occurrence that a jailedside-branch cannot be accessed
with a pressure wire. We place a double-bend on the pressure wire (a distal 50–60 degrees bend
and a more proximal 40 degrees bend), wire themain vessel so that thetip of the wire is beyond
the side branch, and then pull the wire back while torquing the tip toward the ostium of the
side branch. Occasionally, subtle changes in the bend are necessary when the initial curvature
does not access the branch vessel.
Case #4
A 57-year-old man is found to have a complex series of lesions within his LCx and large
first OM branch [Fig. 6(A)]. The mid-OM lesion is seen at a branch point in the vessel that
the operator intends to stent and then there is an irregular nature to the LCx–OM bifurcation
that the operator also intends to stent. Working distal to proximal, the OM lesion is stented
and the side branch off of the main OM is felt to be too small to require subsequent treatment. The proximal OM is then stented, with the stent starting in the LCx proper, thereby
“jailing” the AV-LCx. Subsequent angiography [Fig. 6(B)] demonstrates a “pinch” in the ostium
of the AV-LCx. A pressure wire is then directed through the stent struts and into the distal
AV-LCx, intravenous adenosine is given, and the FFR of this branch was found to be 0.83.
Although not normal, thisvalue is above the ischemicthreshold and theoperator elected to perform a final angiogram and end the procedure at this point with a successful result [Fig. 6(C)].
As in previous cases, the reader should note that lesions that occur in “jailed” side branches are
74
LIM AND KOO
(B)(A)
Figure 5 (A) Coronary angiography in the RAO caudal projection demonstrating a severe stenosis in the
circumflex artery that appears to arise distal to a large OM branch. (B) Follow-up angiography after the circumflex
is stented, showing a change in the take-off angle of the branch without severe stenosis. (C) Final angiography
prior to the completion of the procedure.
not usually associated with a physiologically significant stenosis, despite their disconcerting
angiographic appearance.
Case #5
A 53-year-old man is found to have a subtotal occlusion of the proximal LAD [Fig. 7(A)].
The operator elects to wire the LAD, which is accomplished easily with a hydrophilic wire,
and the vessel is subsequently ballooned and stented [Fig. 7(B)]. Subsequent angiography
demonstrates that there is a moderately sized diagonal branch that was “jailed” by the LAD
stent, and the ostium appears to be significantly obstructed by angiography [Fig. 7(C)]. As
previously described, a pressure wire is placed into the LAD and across the stent struts into the
diagonal branch [Fig. 7(D)]. FFR is performed andis foundto be 0.76. Atthis point, the operator
(C)
PHYSIOLOGIC GUIDANCE OF PROVISIONAL STENTING IN CORONARY BIFURCATION LESIONS
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
(B)(A)
75
Figure 6 (A) Coronary angiography in the RAO caudal projection demonstrating multiple lesions within the
circumflex and first obtuse marginal branch. (B) Angiogram after stenting across the AV-circumflex and into the
OM branch. (C) Final angiography.
decides to further treat the bifurcation with kissing balloons in the LAD and in the diagonal
(over the pressure wire). After removal of the balloons, follow-up FFR of the diagonal branch
becomes 0.93 and the procedure is completed [Fig. 7(E)]. This case shows that even when a side
branch is not readily apparent on initial angiograms, its appearance after main branch stenting
can be handled in a similar manner. Performing kissing balloon inflations over a pressure wire
does not require any specialtechniques and does not compromisethe wire to be able to perform
subsequent FFRmeasurements. Follow-upFFR in theside branch becoming nonphysiologically
significant is a finding that we utilize to avoid stenting the side branch. In our experience, the
inability to“normalize” an FFR above theischemic threshold ismost often related to dissections
arising in the ostia of the side branch and is the sign that a side branch stent needs to be placed.
Additional case examples that illustrate how FFR can be utilized in bifurcation stenting
are shown inFigures 8–11. The combinationof IVUS andFFR to treatan LAD lesionis shown in
Figure 8. The case in Figure 9 shows an example of patient with a left main lesion treated with
(D)(C)
(B)(A)
(D)(C)
(E)
Figure 7 (A) Coronary angiography in the RAO caudal projection showing a subtotal occlusion of the LAD.
(B) Stent placement in the LAD. (C) LAO cranial angiogram demonstrating a stenosis in a “newly discovered”
diagonal branch. (D) Pressure wire in the diagonal branch before measuring FFR. (E) Final angiogram.
MLD: 1.8 mm
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
MLA: 3.0 mm
2
MLD: 1.8 mm
MLA: 3.1 mm
2
(A)
Mid-LAD
Lt Main
Cypher 3.5 ×
13
(B)
(C)
Figure 8 (
scan (
intravascular ultrasound, minimal lumen area was 3.0 mm
See color insert
left
). Angiogram showed the stenoses located at the mid-LAD and proximal LAD bifurcation segments. By
)(A) A 57-year-old man was admitted due to the abnormality in a radionuclide
2
at mid-LAD and 3.1 mm2at LAD ostium. (B) FFR at
distal LAD was 0.69. A significant pressure step up was found only at a LAD ostial lesion in a pressure pull-back
curve (
green line
). Therefore, additional stent was implanted at the LAD ostium. (C) A radioisotope scan six
months after stent implantation shows no perfusion defect.
Соседние файлы в папке Библиотека им академика М.И. Перельмана