Tx Delay Impacts Microvascular Reperfusion in STEMI

Symptom onset-to-balloon time linked to absent microvascular perfusion, STR <;30 percent

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MONDAY, Jan. 4, 2016 (HealthDay News) -- For patients with ST-segment elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention (PCI), delayed reperfusion therapy is associated with greater microcirculation injury, according to a study published in the Dec. 28 issue of JACC: Cardiovascular Interventions.

Abhiram Prasad, M.D., from Mayo Clinic in Rochester, Minn., and colleagues examined the effect of treatment delay on microvascular reperfusion in STEMI patients from the Harmonizing Outcomes with Revascularization and Stents in Acute Myocardial Infarction trial. Resolution of ST-segment elevation (STR) and the myocardial blush grade (MBG) were used to examine the effect of symptom onset-to-balloon time (SBT) and door-to-balloon time (DBT) on myocardial reperfusion during primary PCI for 2,056 patients.

The researchers found that patients with longer SBT more often had absent microvascular perfusion (MBG 0/1) and STR <30 percent after primary PCI; this was observed for patients with low and high clinical risk profiles. SBT, anterior infarction, reference vessel diameter, lesion minimum lumen diameter, hyperlipidemia, and current smoking were independent predictors of MBG 0/1 in multivariable analysis; independent predictors of absent STR included SBT, anterior infarction, and history of renal insufficiency. DBT was found to be an independent predictor of MBG 0/1. Patients with increased three-year mortality were identified by MBG 0/1 and STR <30 percent.

"The present study suggests that delay in mechanical reperfusion therapy during STEMI is associated with greater injury to the microcirculation," the authors write.

Several authors disclosed financial ties to the pharmaceutical and medical device industries.

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