Remote Ischemic Conditioning Reduces Myocardial Infarct Size and Edema in Patients With ST-Segment Elevation Myocardial Infarction

doi:10.1016/j.jcin.2014.05.015

JACC: Cardiovascular Interventions

Volume 8, Issue 1, Part B, January 2015, Pages 178-188

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Abstract

Objectives

This study aimed to determine whether remote ischemic conditioning (RIC) initiated prior to primary percutaneous coronary intervention (PPCI) could reduce myocardial infarct (MI) size in patients presenting with ST-segment elevation myocardial infarction.

Background

RIC, using transient limb ischemia and reperfusion, can protect the heart against acute ischemia-reperfusion injury. Whether RIC can reduce MI size, assessed by cardiac magnetic resonance (CMR), is unknown.

Methods

We randomly assigned 197 ST-segment elevation myocardial infarction patients with TIMI (Thrombolysis In Myocardial Infarction) flow grade 0 to receive RIC (four 5-min cycles of upper arm cuff inflation/deflation) or control (uninflated cuff placed on upper arm for 40 min) protocols prior to PPCI. The primary study endpoint was MI size, measured by CMR in 83 subjects on days 3 to 6 after admission.

Results

RIC reduced MI size by 27%, when compared with the MI size of control subjects (18.0 ± 10% [n = 40] vs. 24.5 ± 12.0% [n = 43]; p = 0.009). At 24 h, high-sensitivity troponin T was lower with RIC (2,296 ± 263 ng/l [n = 89] vs. 2,736 ± 325 ng/l [n = 84]; p = 0.037). RIC also reduced the extent of myocardial edema measured by T₂-mapping CMR (28.5 ± 9.0% vs. 35.1 ± 10.0%; p = 0.003) and lowered mean T₂ values (68.7 ± 5.8 ms vs. 73.1 ± 6.1 ms; p = 0.001), precluding the use of CMR edema imaging to correctly estimate the area at risk. Using CMR-independent coronary angiography jeopardy scores to estimate the area at risk, RIC, when compared with the control protocol, was found to significantly improve the myocardial salvage index (0.42 ± 0.29 vs. 0.28 ± 0.29; p = 0.03).

Conclusions

This randomized study demonstrated that in ST-segment elevation myocardial infarction patients treated by PPCI, RIC, initiated prior to PPCI, reduced MI size, increased myocardial salvage, and reduced myocardial edema.

Key Words

acute myocardial infarction

cardiovascular magnetic resonance

myocardial edema

primary percutaneous coronary intervention

remote ischemic conditioning

reperfusion injury

Abbreviations and Acronyms

AAR

area at risk

AUC

area under the curve

CMR

cardiac magnetic resonance

hsTnT

high-sensitivity troponin T

LGE

late gadolinium enhancement

left ventricular

myocardial infarct

MSI

myocardial salvage index

PCI

percutaneous coronary intervention

PPCI

primary percutaneous coronary intervention

RIC

remote ischemic conditioning

STEMI

ST-segment elevation myocardial infarction

STIR

short tau inversion recovery

Cited by (0)

: This work was supported by grants from the British Heart Foundation (RG/03/007, FS/10/039/28270, and FS/10/72/28568), the Rosetrees Trust, and the National Institute for Health Research University College London Hospitals Biomedical Research Centre. Dr. Frohlich has received a research grant from the Swiss National Foundation. Dr. Davies has received honoraria for attending meetings from Boston Scientific; and has received speaking fees from AstraZeneca and Pfizer Inc.. Dr. Yellon serves on the advisory board to AstraZeneca; and has received research support from Merck Sharp & Dohme. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.