Sen. Lindsey Graham (R-S.C.) died Saturday night at his Washington, D.C. home at age 71, after what his office initially described only as a “brief and sudden illness.” On Sunday, his office released preliminary findings from the District of Columbia’s chief medical examiner: aortic dissection due to arteriosclerotic cardiovascular disease. Emergency medical services had responded to a call for cardiac arrest at the senator’s home. The final death certificate remains pending until toxicology and microscopic testing are complete.

Graham had just returned from his tenth wartime trip to Ukraine, and his staff reported no indication that he was feeling unwell. That combination—apparently fine one moment, in cardiac arrest hours later—is exactly how aortic dissection can unfold. As an ER doctor, it is a diagnoses I think about regularly when I see patients. It can kill within minutes and can masquerade as far more common problems. Here is what the preliminary finding means.

What Is An Aortic Dissection?

The aorta is the body’s main artery, a garden-hose-sized vessel that carries blood out of the heart to every organ. Its wall has three layers. A dissection begins when the innermost layer tears, allowing high-pressure blood to surge into the wall itself and split the layers apart. This creates a false channel where blood flows.

Doctors classify dissections by location. Type A dissections involve the ascending aorta, the segment closest to the heart, and are surgical emergencies. Type B dissections are limited to the descending aorta and can often be managed with blood pressure control and, in some cases, stenting. Type A is the more lethal tyle: the tear can extend backward into the sac around the heart, causing what’s called tamponade where blood compresses the heart until it cannot pump. It can also shear off the arteries that supply the heart muscle itself. Either mechanism produces sudden cardiac arrest, which matches what first responders encountered at Graham’s home.

Why Untreated Aortic Dissection Kills So Quickly

An acute Type A dissection carries a mortality risk that climbs by roughly 1% to 2% every hour after the tear occurs. When the aorta ruptures completely, death can occur in minutes—often before an ambulance arrives. The classic teaching holds that about half of untreated patients die within the first 48 hours, and even when treated about a quarter will not survive.

This is why many dissections are simply unsurvivable outside a hospital. When the first symptom is collapse and cardiac arrest, even perfect CPR and a rapid EMS response are frequently not enough. Nothing in the public reporting suggests any delay in Graham’s care. Rather, his death illustrates the disease’s most severe presentation.

What ‘Arteriosclerotic Cardiovascular Disease’ Means

The second half of the medical examiner’s finding refers to the underlying condition: hardening and degeneration of the arteries from atherosclerosis. This is the same disease process behind most heart attacks and strokes. Decades of plaque buildup, inflammation and, above all, high blood pressure stiffen and weaken the aortic wall. This sets the stage for a tear. Chronic hypertension is the single biggest risk factor for dissection, and is present in the large majority of cases.

Graham’s profile fits the classic epidemiology of the disease. Dissections most often strike men in their 60s and 70s. Family history matters too—his father died of a heart attack in his late 60s. Some outlets have noted the senator’s heavy recent travel schedule, including long-haul flights back from Ukraine and a NATO summit. While fatigue and travel stress don’t cause dissection, transient blood pressure surges can be the final insult to an already-diseased aorta.

That said, attributing his dissection to any single trigger would be speculation. The substrate of arteriosclerotic disease had likely been building for years.

Why Dissection Is So Hard To Catch, Even In The ER

Roughly 20,000 Americans experience a thoracic aortic dissection or related emergency each year, and it is one of medicine’s most notorious mimics. The textbook symptom is sudden, severe, tearing pain in the chest or back, sometimes migrating as the tear extends. Yet dissections can also present as stroke symptoms, abdominal pain, fainting, a cold pulseless limb, or as happened here, immediate collapse.

Compounding the problem, the standard heart attack workup cannot exclude it. An EKG, a chest X-ray and blood tests can all look reassuring while the aorta is tearing. The definitive test is a CT angiogram, which emergency physicians must actively decide to order based on suspicion. Actor John Ritter’s 2003 death from a misdiagnosed dissection led his family to create the Ritter Rules, a public-awareness checklist that emphasizes urgency, the primacy of pain, the risk of misdiagnosis and the importance of family screening for aortic disease.

How To Think About Your Own Risk of Aortic Dissection

Most dissections are the endgame of preventable disease. Controlling blood pressure is the single most powerful protective step, along with not smoking, treating cholesterol and staying active. If a first-degree relative has had an aortic aneurysm, dissection or unexplained sudden death, tell your doctor. Screening imaging can identify an enlarging aorta years before it tears, and genetic conditions that increase the risk of dissection like Marfan syndrome run in families.

Know the alarm symptom: sudden, severe chest or back pain, often described as tearing or ripping, and the worst pain of your life. Don’t wait. It warrants a 911 call. In the ER, it is reasonable to ask directly whether aortic dissection has been considered. Minutes matter more with this diagnosis than with almost any other.

Graham’s death was mourned across the political spectrum this weekend, with tributes pouring in from the president, Senate colleagues and world leaders. It is also a reminder of a hard clinical truth: the most dangerous cardiovascular emergencies are often the quietest—until, suddenly, they are not.