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Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3676_Библиотеки_им_академика_М_И_Перельмана
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9 Cardiac CTA in the Evaluation of Stents
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9.2 Case 9.2
9.2.1 History
A 77-year-old female with a history of prior PCIs
with placement of multiple stents in the LAD,
presented with subsequent CABG. The CTA was
performed for questionable ischemia in the LV
apex on a nuclear perfusion scintigram.
a
9.2.2 Findings
There are multiple sequential occluded stents in
the proximal to mid-LAD and a patent left internal mammary artery graft (LIMA) to the distal
LAD (Fig. 9.2a–d).
c
Fig. 9.2 (a–c) Volume rendering, cMPR, and stretched
LAD–LIMA: Occluded sequential stents in the proximal
to mid-LAD. The lower arrow in (a) and (b) shows a tran-
sition zone between the distal stent and the LAD, indicating an occlusion. There is a patent LIMA graft to the distal
LAD. (d) cMPR: Patent LIMA graft to the distal LAD
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9.2.3 Diagnosis
The diagnosis is chronic total occlusion of the
proximal to mid-LAD. The distal LAD has no
disease and has been bypassed with a LIMA graft
that is patent.
9.2.4 Discussion
There are multiple sequential stents in the proximal to mid-LAD. Note that there is no evidence
of contrast density in the lumen of the stents, and
there is a transition zone in the distal stent, indicating chronic total occlusion. As in this case, it
is not infrequent that following one or multiple
coronary interventions, with subsequent failure
of the stents by subintimal hyperplasia, or thrombosis, that the patient is referred for surgical
revascularization.
9.2.5 Pearls and Pitfalls
Low density alone in the lumen of a stent is not
diagnostic of an occluded stent. Extensive subintimal hyperplasia may mimic an occlusion.
Additional findings such as a distal short lowdensity transition zone or lack of contrast opacification of the distal artery are needed to conclude
that the stent is occluded.
9.3 Case 9.3
9.3.1 History
A 72-year-old female presented with a history of
intermittent chest pain and PCI 2 years prior,
with DESs.
9.3.2 Findings
There is a Y stent in the second diagonal, with low
density in the lumen of the stent indicating restenosis (Fig. 9.3a, b). There is a stent in the LAD,
which has localized focal low density in the lumen
of the distal stent (Fig. 9.3c). Incidentally noted is
a membranous septal aneurysm bulging into the
right ventricle (Fig. 9.3d, e).
9.3.3 Diagnosis
The diagnosis is in-stent restenosis in the second
diagonal artery. Nonobstructive neointimal
hyperplasia in the distal segment of the stent in
the LAD. Incidentally found is a membranous
septal aneurysm.
9.3.4 Discussion
Neointimal hyperplasia in a stent that causes
decreased contrast opacification in the lumen,
bc
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d
ef
gh
Fig. 9.3 (a, b) cMPR and stretched D2: In-stent resteno-
sis (arrow). (c) cMPR LAD: Mild nonobstructing neointimal hyperplasia in the distal stent (arrow). (d, e)
Coronary angiogram pre- and postangioplasty of D2
(arrow). Patent LAD stent. (f, g) CTA axial and coronal
slices: Membranous septal aneurysm (MSA) (arrow). (h)
Angiogram, LV injection: Membranous septal aneurysm
(arrow)
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which appears as low density. Significant restenosis is defined as vessel lumen narrowing of
more than 50% after angioplasty. Restenosis is an
iatrogenic process caused by an excessive arterial
healing response to vessel injury associated with
dilation. It results from the combined effects of
elastic recoil, vascular remodeling, and neointimal hyperplasia. Coronary stents represent a
mechanical approach to the prevention of restenosis by virtually eliminating elastic recoil and
negative remodeling of the vessel after balloon
dilation. The occurrence of neointimal hyperplasia is mainly responsible for the observed rates of
restenosis, which range from less than 10% with
a DES to 40% with an uncoated or bare metal
stent. For both stent types, excess stent length is
associated with an increased risk of in-stent restenosis. The restenosis in the diagonal artery was
confirmed on angiography and was subsequently
ballooned. The focal area of neointimal hyperplasia in the distal stent in the LAD was not significant on the angiogram.
There are various techniques for stenting
bifurcating lesions. Among these are T stent
technique, V stent technique, Y stent technique,
crush technique, and the culottes or trousers technique, which is a variant of the Y technique.
The membranous septal aneurysm was an incidental finding. These may be associated with
many congenital cardiac anomalies and be a cause
of arrhythmia and/or tricuspid valve dysfunction.
9.3.5 Pearls and Pitfalls
The identification of neointimal hyperplasia is
common in CT angiography. The greater challenge is determining whether it is flow limiting
and/or clinically significant, particularly in
smaller caliber vessels, and also overlapping
stents. Correlation with the patient’s symptoms
and a myocardial perfusion scintigram is helpful
to determine whether further evaluation with coronary angiography is warranted.
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9.4 Case 9.4
9.4.1 History
A 73-year-old male presented with a history of
new onset of exertional chest pain and mid-LAD
PCI 10 years prior, with a bare metal stent (BMS).
9.4.2 Findings
There is high-grade stenosis in the range of 90%
in the mid-LAD (Fig. 9.4a–e).
9.4.3 Diagnosis
The diagnosis is high-grade stent restenosis in
the mid-LAD.
a
b
9.4.4 Discussion
The neointimal hyperplasia obscures the stent,
which is poorly identified. In fact, without the
history of the prior PCI, it would not have been
possible to determine, with certainty on the CTA,
the presence and location of the stent in the
mid-LAD.
9.4.5 Pearls and Pitfalls
BMS in place over a number of years may be
obscured by the neointimal hyperplasia and
therefore may not easily be identified on
CTA. It is uncertain at this time whether DES
may also develop a similar appearance after
many years.
cd e
Fig. 9.4 (a–c) cMPR and stretched, volume rendered LAD: stent high-grade restenosis in the mid-LAD (arrow).
(d, e) Correlative coronary angiogram demonstrating 90% stenosis in the mid-LAD (arrow)
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9.5 Case 9.5
9.5.1 History
A 75-year-old female presented with a history of
increasing shortness of breath. The status was
post mid-LAD and LCX PCI in the previous
3 years, with BMS.
9.5.2 Findings
There are two areas of high-grade stenosis in the
mid-LAD. There is a widely patent stent in the
proximal left circumflex (Fig. 9.5a–e).
9.5.3 Diagnosis
High-grade stent restenosis in the mid-LAD and
a second distal segment of high-grade stenosis.
9.5.4 Discussion
The extensive neointimal hyperplasia obscures
the stent, which is poorly identified. The minimal contrast density (string sign) through the
stent and lack of significant transition zone
distally would indicate that the lumen is not
totally occluded. There is a more distal short
segment high-grade stenosis in the LAD
(arrow).
9.5.5 Pearls and Pitfalls
The neointimal hyperplasia should not be confused with a thrombus or plaque rupture in the
arterial lumen. Notice that the distal segment of
the stent is sharp and appears to extend beyond
the lumen of the native artery. It is a good clue
that a stent is present.
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Fig. 9.5 (a–c) Volume
rendering, cMPR and
stretched, LAD: Stent
high-grade restenosis in
the mid-LAD and more
distal in the LAD
(arrows). (d) Composite
Patent stent in
cMPR.
the proximal LCX,
LAD disease (arrows).
(e) Correlative coronary
angiogram demonstrates the two areas of
high-grade stenosis in
LAD (arrows)
the mid-
a
b
c
de
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9.6 Case 9.6
9.6.1 History
A 53-year-old male presented with a history of
atypical chest pain, CAD, and prior multivessel
coronary interventions.
9.6.2 Findings
There is narrowing of the distal lumen of a
DES in the left circumflex coronary artery
(Fig. 9.6a, b).
9.6.4 Discussion
Coronary stents, including DESs, must be optimally
deployed with full lesion coverage and complete
expansion of the stent and complete apposition to
the vessel wall to optimize results. Less than full
expansion and apposition significantly increases the
risk of complications such as subacute thrombosis,
target lesion revascularization, and restenosis, thus
compromising the benefits of the intervention. With
DES, incomplete expansion and apposition can also
impede drug delivery to the vessel wall.
9.6.5 Pearls and Pitfalls
9.6.3 Diagnosis
The diagnosis is underexpanded distal segment
of a DES in the left circumflex coronary artery.
ab
Overlapping stents may have a similar appearance to an underexpanded stent. Significantly
increasing the window width on the workstation
in the range of 1500–3000 may prove helpful.
Fig. 9.6 (a, b) cMPR and stretched, LCX: Underexpanded distal segment of the coronary stent (arrows)
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9.7 Case 9.7
9.7.1 History
9.7.2 Findings
There are widely patent overlapping DESs in the
proximal to mid-RCA. The RCA has diffuse dis-
A 72-year-old male presented with RCA-PCI
2 months prior, with increasing atypical chest
pain.
ease. There is soft tissue (plaque, hemorrhage?)
density in the distal RCA causing high-grade
critical stenosis (Fig. 9.7a–c).
ac
b
Fig. 9.7 (a, b) cMPR and stretched, RCA: Widely patent
overlapping stents in the proximal to mid-RCA (short
arrow). High-grade critical obstruction in the distal RCA
(long arrow). (c) Axial slice demonstrating high-grade
critical obstruction in the distal RCA (arrow)
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9.7.3 Diagnosis
Patent overlapping DES in the right coronary
artery. New onset of high-grade critical stenosis
in the distal RCA, presumably from a guidewire
injury during coronary intervention.
9.7.4 Discussion
Sequential coronary stents may overlap causing
summation metal density on the CTA. During coronary artery intervention, guidewires are placed
distal to the deployment of the stent. Common
complications related to the wire tip include perforation of the coronary artery, with development of
a hemopericardium, subintimal hemorrhage, and
dissection of the coronary artery. Most of these
complications are detected at the time of the procedure or suspected clinically within a matter of
hours. If not diagnosed and treated, these may lead
to chronic unstable angina, acute coronary syndrome, and sudden death. The patient underwent a
repeat coronary angiogram, with successful stenting of the distal RCA. Although it was felt that the
most likely diagnosis was a wire-related injury, a
postprocedure rupture of a plaque, with subintimal
hemorrhage in the wall could not be completely
excluded.
9.8 Case 9.8
9.8.1 History
A 69-year-old male presented with a history of
COPD, presurgical workup for lung CA and prior
PCI in the RCA and left circumflex performed
12 years previously. The study was performed for
preoperative clearance.
9.8.2 Findings
There is a bare metal stent in the proximal RCA
with high-grade proximal edge stenosis. There is
a second bare metal stent in the mid-circumflex,
which has high-grade stenosis in the proximal
and distal edge of the stent and in-stent restenosis
(Fig. 9.8a–c).
9.8.3 Diagnosis
High-grade edge stenosis adjacent to coronary
stents and high-grade restenosis in the stent in the
left circumflex coronary artery.
9.8.4 Discussion
9.7.5 Pearls and Pitfalls
Increasing the window width on the workstation
is helpful in evaluating the segment of overlapping stents.
It has been reported that a frequent occurrence
(48%) of significant stenosis outside of bare
metal stents in patients presenting with symptoms following coronary stent deployment.
The majority of these stenosis also involve stenosis inside of the stent (diffuse proliferative
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