The POSTEMI study of Shanmuganathan Limalanathan and co-workers shows no effect of ischemic postconditioning on infarct size or myocardial dysfunction in PCI-treated STEMI patients.

MAIN RESULTS:

1. Ischemic postconditioning had no additional effect on reducing infarct size at four months in patients with first-time STEMI treated by PCI.
2. Ischemic postconditioning had no effect on reducing left ventricular dysfunction.
3. Microvascular obstruction was associated with impaired myocardial salvage following STEMI treated by primary PCI.

THESIS DEFENCE:

Thesis: Effect of ischemic postconditioning on infarct size and left ventricular function. Results of the Postconditioning in ST-Elevation Myocardial Infarction (POSTEMI) randomized trail.
Candidate: Shanmuganathan Limalanathan
Time: November 10, 2017 at 13:15
Place: Oslo University Hospital Ullevål, The Cancer Centre (Building 11): Ground Floor Auditorum
Link to university website (in Norwegian)

SUMMARY:

(1) Short repetitive cycles of reperfusion and re-occlusion (ischemic postconditioning) has in smaller studies been demonstrated to have a protective effect on the heart following PCI for acute ST-segment elevation myocardial infarction. The Postconditioning in ST-Elevation Myocardial Infarction (POSTEMI) study randomized 272 STEMI patients with proximal or mid-coronary artery occlusion to postconditioning or no postconditioning. All patients were treated less than six hours from symptom onset.

(3) Infarct size measured by cardiac magnetic resonance after four months was not significantly affected by ischemic postconditioning. Results were neutral in both genders and all age groups. Also, there was no significant between-group differences in rehospitalization for acute coronary syndromes or heart failure during follow-up.

Left ventricular ejection fraction, myocardium at risk and myocardial salvage index at four months also did not differ between the two groups. Furthermore, there were no between-group differences in myocardial perfusion grade immediately after PCI, ST resolution one hour after reperfusion or peak troponin T values.

(4) Ischemic postconditioning did not influence myocardial dysfunction, measured as peak systolic strain or post-systolic shortening. The results  suggest that applying postconditioning in STEMI patients will not improve left ventricular function.

(2) In a substudy, microvascular obstruction was present in about half of the 94 patients. These patients had reduced myocardial salvage, defined as myocardium at risk and infarct size measured in the acute state. The association was even more pronounced when myocardial salvage was based on measurements of infarct size at four months. Microvascular obstruction was also associated with large infarct size, lower left ventricular ejection fraction and larger left ventricular end-systolic volume.

REFERENCES:

(1) Limalanathan, S., Andersen, G. Ø., Hoffmann, P., Kløw, N. E., Abdelnoor, M., & Eritsland, J. (2010). Rationale and design of the POSTEMI (postconditioning in ST-elevation myocardial infarction) study. Cardiology, 116(2), 103-109.

(2) Limalanathan, S., Eritsland, J., Andersen, G. Ø., Kløw, N. E., Abdelnoor, M., & Hoffmann, P. (2013). Myocardial salvage is reduced in primary PCI-treated STEMI patients with microvascular obstruction, demonstrated by early and late CMR. PloS one, 8(8), e71780.

(3) Limalanathan, S., Andersen, G. Ø., Kløw, N. E., Abdelnoor, M., Hoffmann, P., & Eritsland, J. (2014). Effect of ischemic postconditioning on infarct size in patients with ST-elevation myocardial infarction treated by primary PCI results of the POSTEMI (POstconditioning in ST-Elevation Myocardial Infarction) randomized trial. Journal of the American Heart Association, 3(2), e000679.

(4) Limalanathan, S., Eritsland, J., Kløw, N. E., Abdelnoor, M., Hoffmann, P., & Andersen, G. Ø. (2015). Influence of ischemic postconditioning on myocardial dysfunction measured by speckle tracking echocardiography in patients with ST-elevation myocardial infarction. International journal of cardiology, 187, 459-461.