OCT Assessment of Late Stent Malapposition after DES

Department of CardiologyThe 2nd affiliated hospital of

HMUJingbo Hou

Certain distance between vascular wall and at least one stent strut.

支架贴壁不良是指至少一个以上支架小梁与血管壁之间存在一定的空隙（距离）；

SM include instant stent malapposition late stent malapposition ： continuous malapposition after

stent implantation. Acquired stent malapposition.

Late stent malapposition -- What is it?

3

Acquired LSM

Baseline

Positive remodeling

No remodeling

Follow-up

* Study by Dr. Abizaid, presented at TCT 2005.

Mechanism for LSM

Vascular wall positive

remodelling

Absorption of

thrombus or plaque

component (in ACS)

Chronic retraction of

stent

Unclear for exact

pathologic mechanism

Delayed healing

Chronic inflammation

Hypersensitive

reaction

Stent strut neointimal coverage

J Am Coll Cardiol Img, 2010; 3:76-84

Malapposition

Which is better?

Long-term follow-up of LSM

BMSn=61

SESN=80

Post-procedure ISA 9 (14.8%) 13 (16.3%)

Resolved ISA 3 (4.9%) 7 (8.7%)

Persistent ISA 6 (9.8%) 6 (7.5%)

Late-acquired ISA 0 7 (8.7%)

ISA at follow-up 6 (9.8%) 13 (16.3%)

Ako J, et al. JACC. 2005; 46(6):1002-1005.

Tanabe K, et al. Circulation. 2005; 111(7):900-905.

Frequency of ISA ---in BMS and DES Trial

BMSn=240

TAXUSN=229

19 (7.9%) 16 (7.0%)

11 (4.6%) 11 (4.8%)

8 (3.3%) 5 (2.2%)

13 (5.4%) 20 (8.7%)

21 (8.8%) 25 (10.9%)

SIRIUS IVUS TAXUS II IVUS

OCT assessment of LSM

• Late stent malapposition is defined when the distance between its inner surface reflection and the vessel wall is more than strut thickness plus polymer thickness plus OCT resolution.

Stent type Metal strut

thickness(μm)

Polymer

thickness(μm)

Malapposition

(μm)

Cypher Select 140 7 ≥160

Taxus Liberte 97 15 ≥130

Firebird Ⅰ 100 10 ≥125

Partner 114 6 ≥130

OCT assessment of LSM

Measurement of MSA and MSD. Double-headed red arrow is MSD. Dotted area is MSA.

LSM in our center

• LSM in 126 DES stents in 68 patients at

least 1 year after implantation were

evaluated by OCT in our department ；

• MSD, MSA, RLA and RSA were examined

by OCT.

Clinical dataPatient number 68

Stent number 126

Age(years) 60.1±10.2

Male gender, n (%) 57(83.8)

Hypertension, n (%) 40(58.8)

Hyperlipidemia, n (%) 23(33.8)

Diabetes Mellitus, n (%) 21(30.9)

Smoking 31(45.6)

Target vessels, n (%)

LAD 65(51.6)

LCX 22(17.4)

RCA 39(31.0)

Stent type, n (%)

Cypher select, n (%) 26(20.6)

Taxus Liberte, n (%) 15(11.9)

Partner, n (%) 51(40.5)

Firebird Ⅰ , n (%) 34(27.0)

Average stent diameter (mm) 3.1±0.5

Average stent length (mm) 25.1±6.8

Quantitative analysis

Patient vessel RSA

(mm2)

RLA

(mm2)

MSA

(mm2)

MSD

(μm)

MSA

/RSA(%)

DES time

(years)

1 LAD 7.2 6.4 5.6 1050 77.8 1.1

2 RCA 7.1 7.0 1.2 310 16.9 1.5

3 LAD 13.1 12.1 1.7 460 13.0 1.9

4 LAD 6.5 4.7 0.9 520 13.9 1.5

5 LAD 5.7 4.7 1.2 800 21.1 1.3

6 LAD 10.3 10.8 1.8 320 17.5 1.3

7 LAD 5.5 5.1 1.3 650 23.6 1.2

14

Late stent thrombosis—DES: Factors to consider

Discontinuation of antiplatelet therapy

Delayedendothelialization

Late incompleteapposition

Polymer hypersensitivity/inflammation

Late stentthrombosisLate stentthrombosis

Clinical information

• Male ， 43-year-old ； • 2008-4-18:

Selective PCI for subacute anterior MI ，2 DES stents were implanted along

LAD ；• Long smoking and drinking history.

• No hypertension and diabetic history.

Clinical information

• 2009-7-30 ： After stopping using of clopidogrel

for 2 months, the patient had acute

anterior MI again. Thrombolytic

therapy was given to him in local

hospital.

• 2009-8-12 ： CAG.

2008-4-18

2008-4-18

2009-8-18 2008-4-18

2008-4-18

2009-8-18

2009-8-18

Possible reason for late thrombus and recurrent MI

• Comparison of CAG of two times of PCI, we found

obvious coronary positive remodel.

• The change of vascular wall induce late stent

malapposition.

• Late stent malapposition and stop using of dual

antiplatelet therapy were probable reasons for very late

stent thrombosis.

What can we get from this case?

How to prevent late stent malapposition ？☺Choose suitable type of stent in ACS (BMS

or others).

☺New type stents without polymer or

biodegradable polymer to induce

reendothelization.

☺Drug therapy to prevent vascular wall

positve remodelling??

Treatment to LSM……

☺ Prolonged dual antiplatelet treatment.

How long??

☺ Implantation for another stent.

BMS or covered stent?