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 stop receiving oxygen and nutrients, and they die. This tissue death is permanent. Infarction can happen in nearly any organ, including the heart, brain, lungs, kidneys, spleen, and intestines, and the severity depends entirely on where it occurs and how much tissue is affected.
How Infarction Happens
Every organ in your body depends on a constant flow of oxygen-rich blood. When something blocks an artery feeding that organ, the tissue downstream enters a state called ischemia, meaning it’s starved of oxygen but not yet dead. If blood flow is restored quickly, the tissue can recover. If the blockage persists, ischemia crosses a threshold into infarction: the cells die and cannot regenerate.
The speed of the blockage matters. A sudden, complete obstruction often causes a large area of tissue death because the body has no time to adapt. A gradual narrowing, on the other hand, sometimes allows nearby blood vessels to expand and reroute blood around the obstruction, a process called collateral circulation. This is why two people with the same degree of artery disease can have very different outcomes.
What Blocks Blood Flow
The most common cause of infarction is a blood clot, or thrombus, that forms inside an artery. In heart attacks, this typically happens when a fatty deposit (plaque) in a coronary artery ruptures, triggering a clot that seals off the vessel. But clots aren’t the only cause. An embolism occurs when a clot or other debris forms elsewhere in the body, travels through the bloodstream, and lodges in a smaller vessel. This is the primary mechanism behind most strokes and pulmonary infarctions.
Vasospasm, a sudden and severe tightening of an artery wall, can also cut off blood flow without any clot or plaque rupture. Medical guidelines classify heart attacks caused by vasospasm separately from those caused by plaque rupture, because the underlying problem and treatment approach differ. In rarer cases, infarction results from external compression of a blood vessel, as can happen with a twisted or trapped segment of intestine.
Myocardial Infarction (Heart Attack)
Myocardial infarction is the most widely known form. Globally, an estimated 254 million people were living with ischemic heart disease in 2021, and roughly 9 million deaths that year were attributed to it, according to American Heart Association data. A heart attack occurs when a coronary artery becomes blocked and a region of heart muscle dies. The damage typically starts in the innermost layer of the heart wall and spreads outward the longer the blockage lasts.
Doctors confirm a heart attack using a combination of symptoms, electrical activity readings from the heart, and blood tests. The gold-standard blood marker is high-sensitivity cardiac troponin, a protein released by dying heart muscle cells. Troponin levels begin rising within two to four hours of the damage, peak around 24 hours, and can remain elevated for two to three weeks. This extended window makes troponin useful for detecting heart attacks even after the acute event has passed.
Not all heart attacks announce themselves with crushing chest pain. Silent heart attacks produce few or no recognizable symptoms. Some people mistake the sensation for heartburn, a pulled muscle, or the flu. These events still damage the heart and are often discovered later during routine imaging, such as an electrocardiogram or echocardiogram.
Cerebral Infarction (Stroke)
When infarction occurs in the brain, it’s called an ischemic stroke. The sudden onset of neurological symptoms, such as weakness on one side of the body, difficulty speaking, or vision changes, signals that brain tissue is dying. Unlike most other organs, the brain undergoes a different type of tissue breakdown after infarction. While organs like the heart, kidneys, and spleen maintain their structural shape as cells die (a pattern called coagulative necrosis), brain tissue liquefies, leaving behind a fluid-filled cavity.
The specific symptoms depend on which artery is blocked. A blockage in the middle cerebral artery, the most common site, typically causes weakness and numbness on the opposite side of the body, particularly in the face and arm. It can also impair language if it affects the dominant hemisphere, or cause a person to neglect one entire side of their visual world if it affects the nondominant side. Blockages in arteries supplying the back of the brain tend to produce visual disturbances, excessive drowsiness, and coordination problems. Diagnosis relies on rapid brain imaging, typically a CT scan, to distinguish an ischemic stroke from a bleed.
Pulmonary Infarction
Pulmonary infarction is death of lung tissue, usually triggered by a pulmonary embolism: a blood clot that travels to the lungs and blocks an artery there. Not every pulmonary embolism causes infarction, because the lungs have a dual blood supply that can sometimes compensate. However, autopsy studies have found that infarction occurs in roughly 60% of pulmonary embolism cases, a much higher rate than many clinicians expect.
When lung tissue does die, it typically happens within one to two days of the blockage. Symptoms include sharp chest pain that worsens with breathing, coughing (sometimes with blood), and shortness of breath. The affected area may fill with blood from damaged small vessels, giving the infarcted tissue a dark, hemorrhagic appearance that distinguishes it from the pale infarctions seen in the heart or kidneys.
Intestinal Infarction
Infarction of the bowel is one of the most dangerous forms. Acute mesenteric ischemia, as it’s formally known, carries a mortality rate of 60% to 80%. The intestines have limited backup blood supply, so when the main feeding artery is blocked, tissue death can progress rapidly. The hallmark presentation is severe abdominal pain that seems out of proportion to what a physical exam reveals. Diarrhea often follows and may become bloody as the intestinal wall breaks down. Because the early symptoms are vague, diagnosis is frequently delayed, which is a major reason the death rate remains so high.
White and Red Infarctions
Pathologists classify infarctions into two visual categories based on what happens to the tissue after blood flow stops. White (or anemic) infarctions occur in solid, densely packed organs like the heart, kidneys, and spleen. Once the artery is blocked, no new blood enters the area, and the dead tissue appears pale. Red (or hemorrhagic) infarctions occur in organs with looser tissue or a dual blood supply, like the lungs and intestines. Blood seeps into the dying tissue from surrounding vessels, staining it dark red.
This distinction isn’t just academic. Hemorrhagic infarctions carry additional risks from internal bleeding, and they can look different on imaging scans, which affects how doctors interpret the results.
Long-Term Effects of Infarction
Once tissue dies from infarction, it does not grow back. In the heart, dead muscle is gradually replaced by scar tissue, which doesn’t contract. A large enough scar weakens the heart’s pumping ability permanently. In the brain, the liquefied tissue is absorbed by the body, leaving a gap that can cause lasting disability depending on its location and size. In the kidneys and spleen, small infarctions often go unnoticed because these organs have enough reserve capacity to compensate. Larger ones can impair organ function over time.
The consequences of infarction are cumulative. Someone who has had one heart attack or stroke is at significantly higher risk for another, partly because the underlying conditions that caused the first event, such as atherosclerosis or a tendency to form clots, are still present. The tissue that survived the initial event may also be more vulnerable, operating with reduced blood supply from the same diseased arteries.