VII° Corso Nazionale Congiunto
Ultrasonologia Vascolare
Diagnosi e Terapia
Embolia e Microembolia
Bertinoro 2009
ULTRASUONI E STENT
ALFIO AMATO
UO di Angiologia e Malattie della Coagulazione
“Marino Golinelli”
Dpt. Cardio Toraco Vascolare
Policlinico Universitario S.Orsola-Malpighi, Bologna
Direttore: Prof. G.Palareti
II° Corso Nazionale Congiunto
Ultrasonologia Vascolare
Diagnosi e Terapia
Bertinoro 2002
STENT ARTERIOSO DALLA TESTA
AI PIEDI
ALFIO AMATO
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Real Time US Evaluation in
PTA Stentings
The concept of vascular stenting
originated with Charles Dotter in
1969, but did not become part of
clinical practice until the late
1980s.
Stent: controllo
angiografico e con IVUS
Evaluation of Four-Year Coronary Artery Response After SirolimusEluting Stent Implantation Using Serial Quantitative Intravascular
Ultrasound and Computer-Assisted Grayscale Value Analysis for Plaque
Composition in Event-Free Patients
STENT ARTERIOSI E
ULTRASUONI
PTA: la prima metodica di
controllo della angioplastica e’
stato l’EcoDoppler e
successivamente
l’EcoColorDoppler,
 PTA-STENTING, non si
differenziano per quanto riguarda
il tipo di diagnostica, ma nel
riconoscere parete arteriosa e
sistema impiantato.
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Echogenic medical device
such as a stent for insertion
into a biological tissue or
vessel comprising an
elongate tube and having at
least one lumen extending
substantially along a
longitudinal axis.
The elongate tube comprises
a material having an
acoustic impedance different
from the acoustic impedance
of the biological tissue or
vessel of a patient body such
that ultrasonic imaging of
the tube inside the patient’s
body may be achieved.
The elongate tube may
comprise a plastic material
such as polyethylene or any
formable, pliable material.
Perché gli stent
si vedono?
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STENT ARTERIOSI E
ULTRASUONI
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La richiesta di controllo ECD di PTA
deve considerare
1-ESATTA SEDE DEL TRATTAMENTO
2-MATERIALE PARIETALE RESIDUO
3-STENOSI RESIDUA
4-STUDIO EMODINAMICO DOPPLER
5-DISSEZIONI SEGMENTARIE
6-FLAP INTIMALI O FRAMMENTI
MOBILI
STENT ARTERIOSI E
ULTRASUONI
Controllo PTA-STENTING
-LETTURA DELLE MAGLIE
-SEDE DI IMPIANTO PREVISTO
-EVENTUALE MIGRAZIONE
-DIMENSIONI: diametro,
lunghezza.
-STENT IMPRONTATO DALLA
LESIONE
STENT CAROTIDEO
STENT POST RESTENOSI IN SEGUITO A TEA
CAROTIDEA
STENTING CAROTIDEO E TEA
Controllo Non Invasivo dei Trattamenti
CONTROLLI POST TEA
Pervietà della CI e CE
Grado di ristenosi: segmento
trattato, tratto a monte e a valle morfologia e velocitàTrombo parietale e sede
Gradino della CC
Lembi mobili
Dissezioni parietali
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POST-TEA
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STENT ARTERIA ILIACA
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Occlusione di stent: dissezione sottointimale e
stenosi compressiva
Le procedure endovascolari
sempre piu’ diffuse richiedono
abitualmente un importante
utilizzo di xRay.
 Lo sviluppo attuale dei sistemi
EchoColor e Power Doppler,
basic or with armonics, and also
the echo-enhancers bubbles,
…dovrebbe indirizzare ad un
maggior utilizzo nella PTAstenting dei sistemi US.
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STENT ARTERIA POPLITEA (?)
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STENTING CAROTIDEO E TEA
Controllo Non Invasivo dei Trattamenti
CONTROLLI POST TEA
 morfologia :
 ecogenicità della lesione
superficie, estensione,
diametro minimo
 velocità:
 criteri adeguati alla nuova
condizione segmentaria
STENTING CAROTIDEO
Eco Color Doppler
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Adesione dello stent alla parete del vaso
Presenza di angolazioni (kinking) della carotide
interna alla fine dello stent prodotte dalla
diversa compliance fra stent e carotide
Migrazione dello stent
Integrità o rotture dello stent
Eventuali complicanze relative ad un
precedente intervento di endoarterectomia
(distacco di patch)
Diametro – area residua lungo lo stent
PSV – EDV
VALUTAZIONE ECD STENT
I parametri da valutare sono diversi da
quelli che si considerano dopo
intervento chirurgico
• Pervietà della carotide interna
• Pervietà della carotide esterna
• Presenza di stenosi nel segmento trattato
• Presenza di stenosi (nuovo ateroma,
iperplasia, trombo) all’interno dello stent
(in-stent restenosis)
• Presenza di stenosi a monte o a valle dello
stent
• Presenza di trombo parietale
CONTROLLI ECO COLOR DOPPLER
POST TEA
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Color Doppler a 1- 4 - 8 - 12 - 18 mesi.
poi a 2 - 4 - 6 - 8 anni.
Se la carotide controlaterale è stenotica
eseguire i controlli secondo il follow-up per le
stenosi note.
ANALOGHI CONTROLLI POST STENT (?)
E dopo molti anni (?)
ICAROS STUDY
Imaging in Carotid Angioplasties and
Risk Of Stroke
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Registro internazionale
multicentrico stenting carotideo
Indentificazione pazienti ad alto e basso
rischio di stroke ad 1 anno
Biasi GM, Nicolaides AN et Al, J Endovasc Ther, 2001
Biasi GM, Diethrich EB, Nicolaides AN, Circulation, 2004
IVUS IN CAROTID STENTING
CONTROLLI SERIATI
ENDOVASCOLARI
POST PROCEDURA E DOPO 6 MESI
Diametro minimo del lume
 Misurazione dell’area di
impianto
 Area dello stent
 Area dell’iperplasia neointimale
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Cardiol, 2006
Clark DJ et Al, J Am Coll
IVUS IN CAROTID STENTING
I “self-expanding stents”
determinano una notevole iperplasia
della neointima
Processo bilanciato dal tardivo
incremento del diametro dello stent
Dimensioni ridotte dello stent subito
dopo la procedura sono associate
con alto rischio di “in-stent
restenosis”
Clark DJ et Al, J Am Coll Cardiol, 2006
nuovi criteri velocimetrici
Lo stent riduce la compliance
dell’arteria e pertanto i criteri
velocimetrici normalmente
utilizzati per la valutazione della
stenosi possono non essere
applicabili.
 Gli studi in Letteratura in
proposito sono in incremento.
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nuovi criteri velocimetrici
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Lal BK et Al. propongono i seguenti valori
per identificare una carotide normale dopo
stenting (stenosi < 20%):
• PSV < 150 cm/s,
• ICA/CCA ratio < 2.16
J Vasc Surg. 2004 Jan;39(1):58-66
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Dovranno essere definiti nuovi
criteri velocimetrici per le varie
classi di stenosi
Real Time US Evaluation in
Stentings
PTA
In 1988 our group in Bologna, together with
angioradiologists, performed an Echo
Doppler PTA procedure of Common Iliac
Artery stenosis.
It was the first Echo-Duplex guided PTA
treatment in Italy.
We presented the procedure on video-tape
during a session of the Italian Society of
Vascular Pathology.
Real Time US Evaluation in
Stentings
PTA
A young male smoker (aged 42
years), with a segmentary
atheromasic lesion of the
common iliac artery discovered
by Duplex Scanner evaluation for
PAD symptoms,underwent a
simple PTA of the vessel.
Stents were not yet used in clinical
practical.
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PTA-STENTING
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Possibilità di effettuare la procedura
con guida Eco Color Doppler (?) per:
 Valutare gli effetti sulla parete
vasale
 Effettuare brevi campionamenti
Doppler
 Ridurre la durata della manovra
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Real Time US Evaluation in PTA
Stentings
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STENTS CANNOT PREVENT RESTENOSIS
1. Restenosis is believed to start the instant of
balloon angioplasty –stent placement secondary
to the vascular injury that occurs when a narrowed
artery is forcibly expanded.
2. Trauma to the vessel in the form of shearing of
the intima and fissuring on the wall of the vessel
may induce excessive deposition of fibrin,
platelets and leukocytes.
Schatz, Circulation,1989; Palmaz, AJR, 1993; Serruys,
Heparin pilot study, Circul.1996
TREATMENT OF CAROTID STENOSIS:
CAROTID SURGERY OR STENT?
ROLE OF DUPLEX ULTRASOUND
(US):
 Degree of stenosis
 Plaque morphology - soft vs hard
-trhombotic or ulcerous formations
• Detection of HITS by transcranial
Doppler
CAROTID STENTS:
Duplex US follow-up of arterial
remodelling
Diameter increase (over 2 years)
 Neo-intimal thickness increase (up
to 12 months)
 Flow-ratio increase (douring first
year)
 Compliance reduction
 Intravascular us scanning of beta
emitting ((55)Co) stents
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US Evaluation in PTA Stentings
Factors not reducing restenosis
•Type of metal
•Surface area of the stent
•Degree of hoop strength of the stent
•Heparin coating
•Long term Warfarin
•Anti-platelet therapy (?)
Plaques with:
• low echogenicity
• stenosis ≥90%
produced a higher number of embolic particles after
ex vivo balloon angioplasty and stenting.
Therefore these lesions may be less suitable for
balloon angioplasty and stenting with currently
used devices.
Ex vivo human carotid artery bifurcation stenting:
Correlation of lesion characteristics with embolic potential.
Takao Ohki, Michael L. Marin, Ross T. Lyon, George L. Berdejo,
Krish Soundararajan, Mika Ohki, Peter L. Faries, Reese A. Wain, Luis A. Sanchez,
William D. Suggs, Frank J. Veith. J Vasc Surg 1998; 27:463-71
STENT MARKET ?
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17% ANNUAL GROWTH FORECAST IN PERIPHERAL
VASCULAR STENT MARKET.
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MR-velocity mapping in vascular stents to assess
peak systolic velocity. In vitro comparison of
various stent designs made of Stainless Steel and
Nitinol. Jacqueline van Holten, Patrik Kunz,
Paul G. H. Mulder,Peter M.T. Pattynama, Hildo J. Lamb,
Magnetic Resonance Materials in Physics, Biology and Medicine
15 (2002) 52-57
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The missing stent
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Missed Double-J stent by
ultrasonography.
G. Pandurangan, B.Bastani. Nephrol Dial
Transplant (2000) 15: 1099-1100
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The Missing Stent - The Most Improbable
Complication
B. Schmidta, A. Gramseb, A. Heringb, U. Liebersa,
S. Hörniga, M. Johna, C. Witta. Respiration
2005;72:304
Healing of Carotid Stents: A Prospective
Duplex Ultrasound Study
Andrea Willfort-Ehringer; Ramazanali Ahmadi; Michael E.
Gschwandtner; Angelika Haumer; Gottfried Heinz; Wilfried Lang;
Herbert Ehringer
Journal of Endovascular Therapy: Vol. 10, No. 3, 2005
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Day after the stent procedure and at 1, 3, 6, 12, and 24 months
in follow-up:
The maximal thickness and echogenicity of the layer between
the stent and the perfused lumen (SPL) were evaluated.
Echogenicity was classified as echogenic if the SPL layer
was clearly detected in B mode and echolucent if the SPL
layer was barely visible in B mode, its border defined by
assistance of color-coded flow.
1) an early unstable period soon after stent placement
with an echolucent (thrombotic) SPL layer,
(2) a moderately unstable phase with ingrowing
neointima (1–12 months),
(3) a stable phase from the second year on. These data
may indicate the need for different intensities of therapy
and surveillance intervals.
Risk of Stroke in Carotid
Stenting (?)
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Plaque Echolucency Is Not Associated With
the Risk of Stroke in Carotid Stenting
Markus Reiter; Robert A. Bucek; Isabella Effenberger; Johanna
Boltuch; Wilfried Lang; Ramazanali Ahmadi; Erich Minar; Martin
Schillinger.
Stroke. 2006;37:2378-2380
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Survival Following Renal Artery Stent
Revascularization.
Four-year Follow-up.
Mayra Guerrero, Asmir Syed, Sandeep Khosla.
J Invasive Cardiology, 2004
In our database, patients undergoing renal artery
stent revascularization for suspected renovascular
hypertension had an overall survival of 83% at 4
years post procedure. Patients with higher baseline
serum creatinine, male gender, bilateral renal
artery stenosis and systolic dysfunction, had
statistically significant lower survival at 4 years.
The future
It is hoped that the next generation of stents will
combine the mechanical advantages of stents with
pharmacologic advantages and coverings which
will prove to have a substantial impact on the
restenosis issue.