Effect of Distal Embolisation on Effect of Distal Embolisation on Myocardial Perfusion ReserveMyocardial Perfusion Reserve

Following Percutaneous Coronary Intervention:Following Percutaneous Coronary Intervention:A Quantitative MR Perfusion StudyA Quantitative MR Perfusion Study

Selvanayagam JB Selvanayagam JB MBBS, DPhilMBBS, DPhil; Cheng ASH ; Cheng ASH MBBSMBBS; Jerosch-Herold M ; Jerosch-Herold M PhDPhD; Rahimi K ; Rahimi K MDMD;Porto I ;Porto I MDMD; Neubauer S ; Neubauer S MDMD; Banning AP ; Banning AP MDMD

From the University of Oxford Centre for Clinical Magnetic Resonance Research, University of Oxford, UK & Department of Cardiovascular Medicine, Flinders Medical

Centre, Adelaide, Australia and Advanced Imaging Research Center, Oregon Health & Science University, Portland, OR, USA

• Studies using intra-coronary Doppler have shown that a proportion of patients demonstrate persistent impairment in microcirculatory function after PCI,even after substantial conduit area enlargement

• using high resolution quantitative CMR, we sought to investigate this by evaluating PCI-induced changes in myocardial perfusion reserve index (MPRI) and procedure-related myonecrosis

HYPOTHESES

• MPRI is impaired in segments with new ‘distal’ PCI-induced injury

• myocardial segments ‘upstream’ to the injury in the territory of the culprit vessel would not demonstrate persistent microvascular dysfunction after PCI

Background

40 patients 40 patients CMR scan 24 hours CMR scan 24 hours

post PCIpost PCI

14 excluded:14 excluded:HE on CMRHE on CMR scan pre PCIscan pre PCI

30 excluded: 30 excluded: clinical history of MI, CTO, clinical history of MI, CTO,

contraindications to MRI/adenosinecontraindications to MRI/adenosine

68 patients68 patients eligible eligible

98 patients 98 patients screenedscreened

10 declined10 declined

44 patients 44 patients CMR scan pre PCICMR scan pre PCI

20 patients20 patientsCMR scan 6 months

post PCI post PCI

Methods

Results

22.

53

Pre PCI 24h Post PCI 6 months FU

Distal HE Upstream Control

Mean MPRI Score (95% CI)

Results

Table 1

HE denotes hyperenhancement, MPRI myocardial perfusion reserve index, PCI percutaneous coronary intervention. Upstream=myocardial segments supplied by the culprit vessel proximal to the distal HE; Remote=segments that underwent PCI in a second vessel in the same patients but not displaying new injury; distal HE=segments demonstrating new distal injury; No PCI=Segments that are subtended by arteries that did not undergo PCI

MPRI

No of

segments Pre-PCI 24h post-PCI Change after 24h z-

value p-value

1. Affected segments in all 40 patients

No HE 322 2.06 (1.99, 2.13) 2.52 (2.42, 2.62) 0.46 (0.36, 0.56)

HE (distal) 82 2.16 (1.95, 2.37) 2.00 (1.82, 2.19) -0.16 (-0.29, -0.02) -4.82 <0.001

2. Affected segments in 21 patients with distal new injury

No HE 170 2.18 (2.07, 2.30) 2.35 (2.22, 2.47) 0.17 (0.04, 0.29)

HE (distal) 82 2.16 (1.95, 2.37) 2.00 (1.82, 2.19) -0.16 (-0.29, -0.02) -6.85 <0.001

3. All segments in 21 patients with distal new injury

Upstream (reference group) 141 2.18 (2.05, 2.30) 2.31 (2.17, 2.44) 0.13 (0.03, 0.23) - -

Distal 70 2.22 (1.98, 2.45) 2.05 (1.84, 2.26) -0.17 (-0.32, -0.02) -4.88 <0.001

Remote 90 2.22 (2.08, 2.37) 2.43 (2.25, 2.60) 0.20 (0.02, 0.39) 0.68 0.50

No PCI 146 2.24 (2.08, 2.39) 2.42 (2.31, 2.54) 0.19 (0.04, 0.33) 0.70 0.48

Results

Table 2

1.0 (0.9, 1.1)

Stress MBF Stress MBF (ml/min/g)(ml/min/g)

Rest MBF Rest MBF (ml/min/g)(ml/min/g)

HE denotes hyperenhancement, MBF myocardial blood flow, PCI percutaneous coronary intervention. *when compared with pre-PCI value, **when compared with 24 hour post-PCI value

PP value value

2.8 (2.3, 3.3)

Pre PCI (HE positive)Pre PCI (HE positive)

Pre PCI (HE negative)Pre PCI (HE negative)

2.2 (1.9, 2.5)

2.2 (2.0, 2.4)1.0 (0.9, 1.1)

0.01*

Early Post PCI (HE Early Post PCI (HE

negative)negative)

Late post PCI (HE negative)Late post PCI (HE negative)

Early post PCI (HE Early post PCI (HE positive)positive)

1.9 (1.7, 2.1) 1.0 (0.9, 1.2)

Late Post PCI (HE positive)Late Post PCI (HE positive)

0.03*

0.8**

0.03**

1.1 (0.9, 1.3)

1.0 (0.9, 1.1)

2.7 (2.3, 3.0)

1.2 (0.9, 1.4) 2.8 (2.3, 3.3)

Results

Results

Remote: segments in the same patients subtended by a vessel that was intervened upon and which had no new HE

Upstream: segments supplied by the culprit vessel, proximal to the distal HE

Distal HE: segments demonstrating new distal HE

Conclusions

• MPRI is reduced in segments demonstrating new ‘distal’ irreversible injury at 24 hours after PCI

• These reductions are transient and confined to the segments with injury

• Microcirculatory impairment early after PCI may be due to both new myonecrosis and transitory macro/microvascular plugging of the vascular bed