MUSTELA: A Prospective, Randomized Trial of Thrombectomy

vs. no Thrombectomy in Patients with ST-Segment Elevation Myocardial Infarction and Thrombus-Rich Lesions

Anna Sonia Petronio, MDCardiothoracic and Vascular Department, University of Pisa

I, Anna Sonia Petronio, DO NOT have a financial interest/arrangement or affiliation with one or more organizations that could be perceived as a real or apparent conflict of interest in the context of the subject of this presentation.

Vlaar P. et al, Lancet 2008; 371: 1915–20

Trial MBG ≥ 2 TIMI 3 No-reflowSlow flow

MACE Infarct size STR MVO

AIMIjacc 2006

91.8%P=0.02

6.7%P=0.01

12.5%P=0.03

EMERALDJama 2006

10.0%P=0.66

12.0%P=0.15

63.3%P=0.78

31.5%P=0.0005

DEAR-MIJacc 2006

88%p=0.0001

89%P>0.20

3%P=0.04

68%p 0.05

EXPIRAJacc 2009

88%p=0.001

64%p 0.001

JETSTENTJacc 2010

80.6%P>0.20

11.2%p 0.011

11.8%P>0.20

85.8%p 0.043

VAMPIREJacc Card Int

2011

46.0%P=0.001

12%P=0.07

12.9%P=0.05

Study design• First MI with high thrombotic burden• Randomization 1:1 to thrombectomy

(Rheolityc/Manual)• Clopidogrel 600 mg oral load before PCI • Abciximab administration during PCI• Stratification for anterior wall MI

Cardiothoracic Dept,University of Pisa

Cardiology Unit,Pisa General Hospital

Cath

Labs

Monasterio Foundation-CNR,Pisa

MRI

Monasterio Foundation-CNR,Massa

•STEMI with symptom onset <12 hours (ST elevation ≥ 2 mm in at least 2 contiguous leads or new LBB block)•High thrombus burden (TIMI thrombus grade ≥3) at diagnostic angiography•No contraindications to abciximab treatment•Written informed consent

•Previous MI in the same ventricular wall•Recent PCI (<2 weeks)•STEMI with cardiogenic shock•Contraindications to abciximab•Contraindications to MRI

1. Infarct size at 3 months (assessed with delayed-enhancement MRI)

2. ST-segment elevation resolution >70% at 60 minutes after primary PCI

1. Microvascular obstruction (3-month MRI)2. Infarct transmurality (3-month MRI)3. DysHomogeneous scar (3-month MRI)4. Postprocedural TIMI flow grade5. Postprocedural TIMI myocardial

perfusion grade6. MACE-free survival at 1 year

viable

No-reflowNo-reflowNon viableNon viable

Voxel containining Voxel containining only scar tissueonly scar tissue

Voxel Voxel containing containing only viable only viable myocitesmyocites

Islands of viable myocardium Islands of viable myocardium with a scar core with a scar core

or diffuse small scarsor diffuse small scars

Voxel Voxel containing containing only viable only viable myocitesmyocites

Left ventricular mass160 g

Delayed enhancement by manual contour tracing

42 g (26%)

Delayed enhancementby semi-automatic gray-

scale analysis33 g (20%)

Randomized (n=208)

No aspiration (n=104)Aspiration (n=104)

Rheolytic (n=54)

No MRI (n=29) Dead (n=2) Refused MRI (n=25) Lost at f-up (n=1) Claustrofobia (n=1)

3-month MRI(n=41)

3-month MRI (n=75)

Primary endpoint analysis (n=79)

Primary endpoint analysis (n=75)

1-year follow-up n=68

Manual (n=50)

No MRI (n=25) Dead (n=3) Refused MRI (n=21) Lost at f-up (n=1)

1-year follow-upn=73

3-month MRI(n=38)

Control(N=104)

Thrombectomy(N=104) P

Age 61.5±14.9 63.0±11.2 0.7

Male sex 79 (76%) 88 (88.4%) 0.83

Diabetes 21(20.4%) 20 (19.2%) 0.83

Hypertension 49 (47.6%) 54 (51.9%) 0.53

Dyslipidemia 45 (43.7%) 54 (51.9%) 0.23

Current smoker 51 (49.5%) 50 (48.1%) 0.81

Renal failure 5 (4.9%) 3 (2.9%) 0.46

Previous MI 2 (1.9%) 4 (3.8%) 0.68

Control Thrombectomy p

Pain–to-balloon time, m 241±161 260±132 0.07

Max ST elevation, mm 4.1±2.1 4.2±1.7 0.21

Total ST elevation, mm 11.7±7.3 12.7±7.8 0.18

N° of leads with ST elevation 4.3±1.5 4.6±1.7 0.34

Anterior wall MI 48 (46.2%) 49 (47.1%) 0.89

Three-vessel disease 9 (8.7%) 14 (13.5%) 0.27

Area at risk (angiography) 23.5±8.4 24.9±8.9 0.19

Killip Class 3 9 (8.7%) 4 (3.8%) 0.10

LVEF, % 46±10 46±8 0.90

Control Thrombectomy P

Thrombus Grade

3 15 (14.4%) 7 (6.7%) 0.07

4 15 (14.4%) 12 (11.5%) 0.50

5 74 (71.2%) 85 (81.7%) 0.07

Initial TIMI flow

0-1 81 (77.9%) 95 (91.3%) 0.007

2 6 (5.8%) 5 (4.8%) 0.70

3 17 (16.3%) 4 (3.8%) 0.002

Initial cTFC 86±28 95±17 0.004

Control Thrombectomy P

Final TIMI flow 0-1 3 (2.9%) 3 (2.9%) 0.682 16 (15.4%) 7 (6.7%) 0.043 85 (81.7%) 94 (90.4%) 0.07

Final cTFC 28±21 24±17 0.17Final MBG 0-1 16 (15.4%) 11 (10.6%) 0.41

2 33 (31.7%) 22 (13.5%) 0.123 55 (52.9%) 71 (68.3%) 0.03

STE resolution >70% 38 (37.3%) 58 (57.4%) 0.004

cTnI peak, ng/mL 73±82 52±62 0.37CK-MB peak, mg/dL 245±290 292±2111 0.60

Control(N=75)

Thrombectomy (N=79)

P

DE area, % 19.3±10.6 20.4±10.5 0.54

DE area >20% 41 (54.7%) 44 (55.7%) 0.90

Transmurality, % 11.6±12.7 11.9±12.0 0.91

MVO 14 (19.4%) 4 (5.1%) 0.01

Dyshomogeneous scar 2 (2.7%) 28 (35.4%) <0.0001

EDVi, mL/m2 80±20 82±24 0.79

Stroke Volume, mL/m2 45±12 45±11 0.80

LVEF, % 59±11 56±12 0.10

• 98% successful delivery 98% successful delivery of thrombectomy catheters:– 98% Manual system– 100% Rheolytic system

• 1 crossover from Manual to Rheolytic system1 crossover from Manual to Rheolytic system, which was successfully delivered to the culprit lesion

• No coronary complications No coronary complications associated with thrombectomy (0 dissections, 0 perforations)

• No prolonged asystole No prolonged asystole with Rheolytic system in RCAs (never placed temporary pacemaker before aspiration)

Procedural results Rheolytic(N=54)

Manual(N=50) P

Angiographic success 51 (94.4%) 39 (78.0%) 0.02Final TIMI flow 3 48 (88.9%) 46 (92.0%) 0.84Final MBG 3 35 (64.8%) 36 (72.0%) 0.56

STE resolution >70% 34 (63.0%) 27 (54.0%) 0.47

MRI results Rheolytic(N=41)

Manual(N=38) P

DE area, % 17.5±9.6 21.3±11.3 0.10

DE area >20% 21 (51.2%) 23 (60.5%) 0.40

Transmurality, % 11.9±12.3 11.8±11.7 0.97

MVO 3 (7.3%) 1 (2.7%) 0.62Dyshomogeneous scar 18 (43.9%) 10 (27.0%) 0.16

92.3±2.8

93.9±2.4

P=0.57

• Thrombectomy was not associated with a significant reduction in infarct size at 3-month MRI, even in a high-thrombus burden STEMI population

• However, thrombectomy was associated with a significantly higher rate of complete STE resolution, and of post-procedural myocardial perfusion grade 3, and with a lower rate of final TIMI 2 flow

• Thrombectomy was associated with a different MRI pattern of myocardial scar at 3 months, with less microvascular obstruction and with areas of viable tissue interspersed with necrotic areas

• No significant difference was observed regarding 1-year freedom from MACEs

• Angiojet was superior to Export in terms of thrombus removal, but not regarding procedural and MRI results

The lack of benefit in terms of infarct size might be related to:•little role of the prevention of thrombo-embolization during primary PCI in reducing final infarct size•excellent myocardial referfusion in the standard PCI group (clopidogrel pre-load + abciximab)•imbalance between groups, favoring standard PCI group (shorter pain-to-balloon time)