UC Davis Health is now able to diagnose heart attacks faster thanks to the use of a blood test only recently approved by the federal Food and Drug Administration last year.
In June, the hospital became one of only two institutions in the state to use the new test, referred to as an hs-cTnT test (an abbreviation of high-sensitivity cardiac troponin subtype T). The test assesses levels of cardiac troponin — a protein in heart muscle cells — in the bloodstream.
Cardiac troponin levels can be measured and evaluated to determine whether someone has had a heart attack.
“When a patient has a heart attack, not enough oxygen is able to reach their heart muscle cells, those muscle cells die, they release their troponin into the blood and we can measure that with a blood test and tell if they’re having a heart attack,” explained Dr. Bryn Mumma, an emergency medicine physician.
In addition to implementing use of the new hs-cTnT test, which looks like any other blood test, UC Davis Health has also restructured the existing algorithm used to evaluate patients with chest pain.
Before, a patient with chest pain had to wait three hours before testing because it takes time for cardiac troponin to enter the bloodstream after heart muscle cells die. But the hs-cTnT test is more sensitive, Mumma explained.
“We can identify those small troponin rises that are coming from a heart attack earlier,” she said. “Some patients can be sent home after a one-hour blood test. It doesn’t sound like much, it’s a difference of two hours, three hours, but when someone is sitting in the emergency department wondering if they have a heart attack, that time matters.”
A faster heart attack diagnosis also means treatment can begin sooner.
“We can … start to get them admitted to the hospital, start to get the cardiologist on board (and) get them the medications they need,” Mumma said.
UC Davis Health officials estimate around 25 patients undergo testing with the cardiac troponin test every day.
“From the emergency department alone, we’ve run about 300 a week,” Mumma said “I’m sure hospital-wide it’s even higher than that — we probably do 5-600 tests a week, at least.”
Since implementing use of the blood test in June, Mumma estimates over 2,000 tests have been administered.
Although UC Davis is one of an estimated 100 institutions in the nation using the hs-cTnT test, other institutions may be in the process of implementing the practice. The test has been used widely in Europe for at least the past five years, Mumma said.
The hs-cTnT test does have one drawback: decreased specificity.
This means clinicians must interpret test results to determine whether elevated levels of cardiac troponin in the bloodstream indicate a heart attack or another cardiac event placing stress on the heart, Mumma said.
The test does determine when a patient is at extremely low risk of having an adverse cardiac event and can be safely sent home, sometimes without any additional testing.
“We can quickly diagnose or rule out the heart attack much faster than we were able to do so before,” Mumma said. “This is good for patients in the sense that it either gets them home or gets them to the care they need more quickly. And it’s good for us as an emergency department for all patients because if we can safely move a patient out of the emergency department either to the in-patient unit or to home, it frees up a bed for someone who would otherwise wait.”