reperfusion

Reperfusion is simply getting the blood flowing again to heart muscle that has been cut off — turning the tap back on for a region that was starved of supply. In a heart attack, it is the single most important goal of emergency care.

It can be achieved in two main ways. Mechanically, an emergency angioplasty (primary percutaneous coronary intervention) threads a catheter to the blockage, inflates a balloon and usually places a stent to hold the artery open. Pharmacologically, thrombolysis injects a clot-dissolving drug to break up the thrombus. The aim of both is to restore flow before too much muscle has died.

The benefit is exquisitely time-dependent: the earlier the artery is reopened after symptoms begin, the more muscle survives and the better the outcome. Reperfusion is not entirely without cost — abruptly restoring flow can itself cause some additional injury and arrhythmias, known as reperfusion injury — but the net benefit of timely reperfusion is large and well established.

Reperfusion is the corrective counterpart to ischemia: ischemia is the loss of flow, reperfusion is its restoration. Achieving it quickly is the central principle behind organized heart-attack care systems.