What is the 60 60 rule for PE?

The 60/60 Rule in Diagnosing Pulmonary Embolism

When doctors suspect a pulmonary embolism (PE)—a potentially life-threatening blockage in the lung’s arteries—time is critical. While imaging like CT pulmonary angiography is definitive, not every patient can undergo it immediately. That’s where tools like the 60/60 rule come in, offering a quick clue during a transthoracic echocardiogram (TTE), a non-invasive heart ultrasound.

The 60/60 rule hinges on two specific measurements seen in the echo. The first is a pulmonary acceleration time (PAT) of less than 60 milliseconds, which reflects how quickly blood speeds up through the pulmonary artery. In cases of acute PE, this time shortens due to sudden pressure in the lung arteries. The second component is a low tricuspid regurgitation (TR) jet gradient—also under 60 mmHg. This may seem counterintuitive, as PE often raises lung pressures, but in early or milder cases, the pressure might not yet be elevated, making this combination particularly telling.

When both values fall below 60, the rule suggests a higher likelihood of PE, especially in the right clinical context. It’s not a standalone diagnosis, but rather a supportive clue—specific, though not very sensitive. That means if the 60/60 sign is present, PE is more likely, but its absence doesn’t rule it out.

This rule is most useful in emergency or bedside settings where rapid assessment matters. Combined with symptoms like sudden shortness of breath, low oxygen, or risk factors such as recent surgery or immobility, it helps clinicians prioritize further testing. While advances in imaging continue, simple, real-time tools like the 60/60 rule remain valuable in the nuanced puzzle of diagnosing pulmonary embolism.