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Medical Daily

Adrian Hayes

An Abnormal Heart Vessel Became a Lifeline, Carrying Blood Around a Man's Fully Blocked Coronary Artery

Disease

A 57-year-old man had two weeks of pressure in his chest whenever he exerted himself. Angiography showed that the middle of his left anterior descending artery, one of the heart's most important blood vessels, was 100% blocked. Yet his heart's overall pumping function was preserved.

Part of the reason was an unusual connection. A side branch of the artery had formed a fistula, an abnormal channel, draining into the left ventricle, the heart's main pumping chamber. That same branch was supplying most of the backup blood flow to the heart muscle beyond the blockage. Cardiologists at Henry Ford Providence Hospital in Bloomfield Hills, Michigan, described the case in JACC: Case Reports on Sept. 9, under the subtitle "An Unusual Coronary Detour."

Chest Pain, a High Troponin and a Blocked Artery

The man's pain was pressure behind the breastbone that did not spread and came on with exertion, along with shortness of breath. That is the classic description of stable angina. MedlinePlus explains that stable angina is caused by "poor blood flow through the blood vessels in the heart called the coronary arteries." His only listed risk factor was high cholesterol, and he had no known coronary artery disease.

His electrocardiogram showed a normal rhythm with nonspecific changes. His troponin, a blood marker of heart muscle injury, was elevated at 230 ng/L. An echocardiogram showed weak movement in the lower part of the heart's tip, but his overall pumping function was preserved.

Coronary angiography, which uses dye and X-rays to show how blood flows through the heart's arteries, found a 100% blockage in the middle of the left anterior descending artery, or LAD. It also found an 80% narrowing near the start of the first diagonal branch, which the team called D1. That branch was "fistulizing into the left ventricle." His other two major coronary arteries had no significant disease.

A Defect That Acted Like a Bypass

Coronary artery fistulas are rare. The authors write that they account for "0.2% to 0.4% of congenital cardiac anomalies." Fistulas that drain into the left ventricle are rarer still, making up only about 3% of all coronary artery fistula cases, according to the report.

Fistulas are usually discussed as a problem. Blood can take the easy route into a low-resistance channel instead of feeding the heart muscle, an effect called coronary steal. A review in RadioGraphics notes that most people with coronary artery fistulas have no symptoms, but symptoms and complications become more common with age.

In this man, the branch that fed the fistula did something else. The report says that "left-to-left collaterals branch from the fistulizing D1 provided the majority of the collateral flow to the LAD." Collaterals are small connecting vessels that can enlarge when a main artery narrows, creating a natural bypass. Rather than stealing blood, the authors concluded, "the fistulizing D1 appeared to serve as a conduit for protective collateral perfusion to the occluded LAD."

In other words, a vessel that would normally be listed as an anomaly on an angiogram report was doing useful work. The authors also point to timing. Because the blockage developed over a subacute period, "preformed coronary collaterals are recruited and undergo remodeling to provide an alternative source of myocardial blood flow, mitigating ischemic injury."

Opening the Artery but Leaving the Fistula Alone

Doctors placed a drug-eluting stent in the blocked section of the LAD, leaving less than 10% residual narrowing and restoring forward blood flow. They also used a balloon to widen the D1 narrowing, reducing it to 50%.

They chose not to close the fistula. According to the report, there was no significant strain on the heart from extra blood volume and no sign that the fistula was stealing blood from the heart muscle. His chest pain with exertion went away after the procedure, and he remained symptom-free at follow-up.

The RadioGraphics review notes that when fistulas do cause symptoms, closing them through surgery or with a catheter-based device is often recommended. In this case, the fistula itself was not the source of his symptoms. The blocked artery was.

That decision reflects the report's main argument. Closing a fistula by reflex could, in some patients, remove a vessel that is actually helping. Deciding what to fix requires a close look at how blood is really moving.

A Case That Challenges a Common Assumption

The authors' take-home message is direct: "coronary artery fistulas are not inherently pathological." They say the case "highlights the importance of individualized anatomical assessment when planning coronary interventions."

The finding comes from a single patient, so it does not mean fistulas are generally protective or that people with them need less monitoring. For readers, the broader point is familiar. The National Heart, Lung, and Blood Institute explains that coronary heart disease occurs when the heart's arteries cannot deliver enough oxygen-rich blood to the heart muscle. Chest pressure with exertion is a warning sign that deserves prompt medical evaluation, whatever the underlying anatomy turns out to be.