Ischemic Postconditioning Reduced Mortality in STEMI Not Treated With Thrombectomy

Patients with ST-segment elevation myocardial infarction (STEMI) who did not undergo thrombectomy were found to have a reduced risk for all-cause mortality and hospitalizations due to heart failure when the intervention included ischemic postconditioning with primary percutaneous coronary intervention (PCI), according to a study recently published in Heart.

Study investigators designed a post hoc analysis of an open-label, randomized controlled trial which had previously investigated STEMI with ischemic postconditioning. To compare the interaction between ischemic postconditioning and intervention with and without thrombectomy, investigators analyzed 1234 patients who used services at 4 PCI centers in Denmark from March 21, 2011 through February 2, 2014. 

Study investigators separated patients into those treated with thrombectomy (n=714) and those not treated with thrombectomy (n=520). Investigators further stratified each patient group by separating them into those treated with conventional PCI and those treated with ischemic postconditioning in addition to primary PCI.

The thrombectomy group included 423 patients with conventional PCI and 291 patients with postconditioning. In the no-thrombectomy group, 194 received conventional PCI and 326 received postconditioning. The primary study end point looked at a combination of all-cause mortality and hospitalizations attributed to heart failure. The secondary end point was cardiovascular death.

After reviewing the follow-up period spanning a median of 35 months, study investigators used a univariable analysis and found that patients not treated with thrombectomy but who had undergone ischemic postconditioning with primary PCI experienced a reduced risk for combined all-cause mortality and heart failure-related hospitalizations (hazard ratio [HR] 0.50; 95% confidence interval [CI], 0.31-0.81; P =.005).

Investigators also found significance in this group for all-cause mortality alone (HR 0.35; 95% CI, 0.19-0.64; P <.001).

In a multivariable analysis of the same group, study investigators found that the association between ischemic postconditioning and the primary end point remained significant even after adjusting for characteristics like age, diabetes, and previous myocardial infarction (HR 0.55; 95% CI, 0.34-0.89; P =.016).

Likewise, multivariable analysis of all-cause mortality by itself also remained significantly associated with ischemic postconditioning in patients who had not been treated with thrombectomy (HR 0.41; 95% CI, 0.22-0.75; P =.004). Additionally, this group of patients experienced less cardiovascular death compared with those treated with conventional primary PCI (HR 0.34; 95% CI, 0.15-0.74; P =.007).

Limitations included the post hoc study design as well as an unbalanced grouping of patients receiving thrombectomy versus those not receiving the treatment. This same lack of balance was present in those groups who had received conventional PCI vs those who received ischemic postconditioning with PCI. These limitations potentially confounded the study results.

The study investigators concluded with noting that “. . .the results presented herein suggest that the promising cardioprotective effects of ischaemic postconditioning should continue to be pursued.” They also noted that while the study’s post hoc design may have limited conclusions, “. . .the results are intriguing and warrant further evaluation in large-scale randomized clinical trials to settle the true impact of ischaemic postconditioning in patients with STEMI.”

Disclosures: One study author declared an affiliation with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.

Reference

Nepper-Christensen L, Høfsten DE, Helqvist S, et al. Interaction of ischaemic postconditioning and thrombectomy in patients with ST-elevation myocardial infarction [published online July 17, 2019]. Heart. doi: 10.1136/heartjnl-2019-314952