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  • Poster presentation
  • Open Access

Impact of successful and failed revascularization of chronic total occlusion on left ventricular function and infarct size

  • Gideon A Paul1,
  • Mo Zia1,
  • Kim A Connelly2,
  • Paul Fefer1,
  • Brad H Strauss1,
  • Alexander J Dick1 and
  • Graham A Wright1
Journal of Cardiovascular Magnetic Resonance201012(Suppl 1):P210

https://doi.org/10.1186/1532-429X-12-S1-P210

Published: 21 January 2010

Keywords

Percutaneous Coronary InterventionCardiac Magnetic ResonanceDrug Elute StentsChronic Total OcclusionTransmural Extent

Introduction

Non-randomised studies have reported a prognostic advantage with percutaneous coronary intervention (PCI) in the treatment of chronic total occlusions (CTO). Failure to cross and successfully open a CTO confers a worse clinical outcome, however most trials have included occlusions of short duration (7-30 days). PCI success rates are inversely related to the age of vessel occlusion reflecting temporal, cellular changes within a CTO, namely progressive collagen deposition.

Purpose

To assess the medium-term cardiac outcomes of PCI in the treatment of true CTO (endorsed by an expert consensus panel, requiring Thrombolysis In Myocardial Infarction [TIMI] flow grade 0 on angiography and ≥12 weeks duration) using quantitative cardiac magnetic resonance (CMR) imaging.

Methods

23 patents (mean age 60 ± 11, 82% male) referred for PCI to a single vessel de novo CTO underwent CMR examination within one week prior to and 6 months after their procedure. PCI success was defined as recanalisation of the occluded vessel and stent implantation with a final residual diameter stenosis <30%. Left ventricular (LV) function and transmural extent of infarction (TEI) were assessed using standard SSFP and T1-weighted imaging on a 1.5 T MRI system. LV volumes and mass were quantified using a dedicated software package (QMass). Segmental wall thickening (SWT) was calculated by (end systolic - end-diastolic wall thickness)/end-diastolic wall thickness × 100%. Myocardial segments were considered dysfunctional if SWT was ≤45%. Viable segments included dysfunctional myocardium with TEI <25%.

Results

TIMI 3 flow was successfully achieved in 13 of the 23 patients (59%), all treated with drug eluting stents. Baseline demographics were well matched in each group (Table 1). Opening a CTO did not result in improvement in either regional or global systolic function however it was associated with a significant increase in SWT in dysfunctional but viable segments (Table 2). Failed PCI was not associated with a worse cardiac outcome in terms of LV remodelling and infarct size as compared to patients with an open artery however one patient experienced a peri-procedural myocardial infarct (MI).
Table 1

Baseline demographics

 

PCI

 

Successful

Failed

No

13

9

Age/y

61 ± 11

 

Male (no/%)

9 (69)

9 (100)

CTO (no/%):

  

• LAD

4 (31)

3 (33)

• LCx

3 (23)

0 (0)

• RCA

6 (46)

6 (67)

CTO duration/mo

5.5 ± 1.5

5.3 ± 1.6

Diabetes: (no/%)

4 (31)

4 (31)

Prior MI: (no/%)

6 (46)

5 (56%)

Prior CABG

1

0

Table 2

Results

 

Success (S)

Failed (F)

S vs F

 

Pre

Post

P

Pre

Post

P

P

EF/%

56 ± 8.9

57 ± 7.6

0.64

57.5 ± 8.8

57.0 ± 6.9

0.76

0.22

LVEDI

62.8 ± 12.2

63.8 ± 14.4

0.61

59.9 ± 9.9

61.4 ± 10.7

0.59

0.89

LVESI

28.4 ± 8.8

27.6 ± 8.8

0.52

25.6 ± 6.86

26.3 ± 6.4

0,68

0.46

Infarct size/g

7.0 ± 5.3

8.7 ± 6.1

0.17

8.0 ± 6.2

10.9 ± 6.8

0.17

0.14

Infarct size/%

9.0 ± 5.9

12.0 ± 7.6

0.19

10.0 ± 7.7

13.3 ± 8.2

0.14

0.86

Segmental wall thickening (SWT)/%

62.6 ± 16.6

62.0 ± 17.9

0.93

56.7 ± 16.8

50.4 ± 19.5

0.32

0.54

Mean change in SWT within dysfunctional but viable myocardium

31 ± 10.1

50.8 ± 23.1

0.02

26.3 ± 9.5

25.8 ± 10.9

0.71

0.047

In hospital outcomes: Death/NQMI Stent thrombosis CK-MB > 3 upper limit

 

0

  

0

  
  

0

  

0

 

NS

  

0

  

1

  

Conclusion

In this single-centre pilot study failed revascularisation of true CTOs was not associated with worse cardiac outcomes compared to successful PCI. Despite a lack of improvement in global systolic function opening a CTO improved SWT within dysfunctional but viable segments. Larger, randomised studies are required to assess the long-term benefits and morbidity of PCI in the treatment of CTOs.

Authors’ Affiliations

(1)
Sunnybrook Health Sciences Centre, Toronto, Canada
(2)
St Michael's Hospital, Toronto, Canada

Copyright

© Paul et al; licensee BioMed Central Ltd. 2010

This article is published under license to BioMed Central Ltd.

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