Heart Attack Test Delivers Results in One Hour

A more sensitive blood test for heart attack may cut the diagnosis time to one hour, removing the need for prolonged monitoring of patients who present to the Emergency Department (ED).

The test, which screens more sensitively for changes in a standard biochemical marker for myocardial infarction or heart attack, may help move patients more quickly through the ED, thus reducing congestion and saving time and money.

Scientists at the University Hospital Basel (Switzerland) recruited 872 patients who presented to the ED with acute chest pain in a multicenter study. The cornerstone for diagnosing acute myocardial infarction (AMI) relies on clinical assessment, electrocardiography and measurement of a biochemical marker called cardiac troponin (or cTn). Without a rapid test for the marker, it can take three hours or more to check for increases in levels.

Blood samples for the determination of high-sensitivity cardiac troponin (hs-cTnT) were collected in serum tubes at presentation to the ED and additional samples were collected hourly thereafter. The samples were assayed in a blinded fashion using the Elecsys 2010 analyzer (Roche Diagnostics; Basel Switzerland). The team developed an algorithm for half of the patients and validated it in the remaining half. The algorithm used baseline hs-cTnT and absolute changes in levels of the biochemical marker within the first hour.

The final diagnosis of AMI was made in 147 (17%) of the patients. When they validated the test in the second group of patients, within one hour it classed 60% (259 patients) of them as rule-out, 17% (76) as rule-in, and 23% (101) as being in the observational zone. They found the cumulative 30-day survival was nearly 100%, 98.6% and 95.3% for patients classed as rule-out, observational zone, and rule-in respectively.

Tobias Reichlin, MD, the lead author of the study said, "Using a simple algorithm incorporating hs-cTnT baseline values and absolute changes within the first hour allowed a safe rule-out as well as an accurate rule-in of AMI within one hour in 77% of unselected patients with acute chest pain. This novel strategy may obviate the need for prolonged monitoring and serial blood sampling in three of four patients." The study was published on August 13, 2012, in the journal Archives of Internal Medicine.

Related Links:
University Hospital Basel
Roche Diagnostics