An infarction is the death of tissue caused by a blocked blood supply. When blood flow to any part of the body is cut off long enough, the cells in that area run out of oxygen, stop functioning, and permanently die. The term applies to any organ, not just the heart. You can have an infarction in the brain (a stroke), the lungs, the kidneys, the spleen, or the intestines.
How Tissue Death Happens
Every cell in your body needs a constant supply of oxygen to produce energy. When an artery or vein becomes blocked, whether by a blood clot, a buildup of plaque, or an embolism (a clot that travels from somewhere else), the tissue downstream is starved of oxygen. This oxygen deprivation is called ischemia, and in its early stages it’s reversible. Restore blood flow quickly enough, and the tissue recovers.
But there’s a threshold. In the heart, as little as 20 minutes of complete blood flow interruption triggers a wave of cell death that starts in the innermost layer of the heart muscle and spreads outward. The cells’ energy reserves collapse, their internal structures break apart, and the tissue begins to die permanently. At that point, ischemia has become infarction. The difference between the two is reversibility: ischemia is the warning, infarction is the damage done.
Exactly how long tissue can survive without blood depends on the organ. Brain cells are the most vulnerable, with irreversible damage setting in within minutes. Heart muscle can tolerate roughly 20 to 40 minutes. Other organs with richer blood supply networks may last longer.
White and Red Infarctions
Not all infarctions look the same under a microscope. Pathologists classify them into two broad types based on what happens to the tissue afterward.
- White (anemic) infarctions occur when an artery is blocked in a solid organ with a single blood supply. The tissue simply dies and turns pale because no blood reaches it at all. These are most common in the spleen, kidneys, and heart.
- Red (hemorrhagic) infarctions occur in organs that have a dual blood supply, or when a vein rather than an artery is blocked. Blood leaks into the dying tissue from nearby vessels, giving the damaged area a dark red appearance. The intestine and lungs are typical sites.
There’s also a difference in how the dead tissue breaks down. In most organs, the cells die but hold their shape for a time, a pattern called coagulative necrosis. In the brain, however, the dead tissue liquefies, turning into a soft, fluid mass. This distinction matters clinically because it affects how the damage appears on imaging and how the body heals afterward.
Myocardial Infarction (Heart Attack)
A myocardial infarction is the most widely recognized form. It happens when one or more of the coronary arteries supplying the heart muscle become completely blocked, usually because a fatty plaque ruptures and a blood clot forms on top of it. Within minutes, the oxygen-starved heart muscle begins to fail. The muscle fibers relax, the energy-producing structures inside each cell deteriorate, and the tissue progresses toward permanent death.
Doctors confirm a heart attack by measuring a protein called troponin in the blood. When heart muscle cells die, they release troponin into the bloodstream, and even small elevations above normal levels signal damage. The current diagnostic standard requires both a rise and fall in troponin concentration (showing it’s an active event, not a chronic condition) along with other evidence of reduced blood flow to the heart, such as chest pain, ECG changes, or imaging findings.
The speed of treatment determines how much heart muscle survives. Every minute counts: the longer the artery stays blocked, the more the zone of dead tissue expands outward through the heart wall.
Cerebral Infarction (Stroke)
A cerebral infarction is a stroke caused by a blocked blood vessel in the brain. The brain consumes enormous amounts of oxygen relative to its size, so it tolerates blood flow interruptions poorly. Animal studies have shown that ischemic damage in the brain becomes irreversible after roughly 3 hours, though some tissue dies much sooner than that.
This is why stroke treatment is famously time-sensitive. Clot-dissolving medications are most effective when given within a few hours of symptom onset, and the benefit drops with every passing minute. The phrase “time is brain” reflects the reality that approximately 1.9 million neurons die every minute during a typical large-vessel stroke.
Unlike the heart, where dead tissue stays relatively firm, infarcted brain tissue liquefies. This creates a soft, damaged area that the body eventually walls off, but the lost neurons are not replaced. Whatever function those neurons controlled, whether movement, speech, or sensation, may be permanently impaired depending on the size and location of the infarction.
Bowel (Mesenteric) Infarction
Mesenteric infarction occurs when blood supply to part of the intestine is cut off. It’s less common than heart attacks or strokes, but it’s one of the most dangerous forms of infarction. The intestines are rich with bacteria, and when the bowel wall dies, those bacteria can leak into the abdominal cavity, triggering severe infection.
A retrospective study of surgical patients with acute mesenteric ischemia found an in-hospital mortality rate of 50%, with most deaths occurring in the first week after surgery. Older age, arterial (rather than venous) clots, and the length of dead bowel requiring removal were all strongly associated with worse outcomes. Patients who survived the initial hospitalization had a five-year survival rate of about 75%, though the first year remained the highest-risk period.
Symptoms typically include sudden, severe abdominal pain that’s out of proportion to what a doctor finds on physical examination. Nausea, vomiting, and bloody stool may follow as the tissue deteriorates.
Splenic Infarction
The spleen filters blood and supports the immune system, and it’s vulnerable to infarction when blood clots or abnormal blood cells block its arteries. About half of people with a splenic infarction experience left-sided abdominal pain, and roughly a third develop a fever. But nearly a third have no symptoms localized to the spleen area at all, meaning it can go unnoticed.
The two most common causes are clot-related disorders (such as atrial fibrillation or heart valve problems sending clots to the spleen) and blood diseases. In people under 40, blood disorders like sickle cell disease are the leading cause. In sickle cell disease, episodes of low oxygen cause red blood cells to deform into rigid, crescent-shaped cells that jam small blood vessels and block flow.
What Determines How Much Damage Occurs
Several factors affect whether an infarction is minor or catastrophic. The most important is time: the longer tissue goes without blood, the larger the area of permanent death. But other factors play a role too.
Organs with a dual blood supply, like the lungs and liver, are somewhat protected. If one artery is blocked, blood may still reach the tissue through a second pathway, limiting the damage. Organs with a single arterial supply, like the kidneys and spleen, don’t have this backup.
The body’s overall oxygen-carrying capacity also matters. Someone with severe anemia or underlying lung disease has less oxygen in their blood to begin with, so even a partial blockage can push tissue past the point of no return. Pre-existing narrowing of blood vessels means the tissue was already getting less blood than normal, leaving a thinner margin before infarction begins.
Finally, the metabolic demand of the tissue is critical. The brain and heart consume oxygen at very high rates, which is why they’re damaged fastest when blood supply is interrupted. Tissues with lower metabolic rates, like bone or cartilage, can survive longer periods of reduced blood flow.