In One-Hour: A Diagnosis of Heart Attack made possible by one Blood Test
Reporter: Larry H Bernstein, MD, FCAP
Voice of Dr. Larry:
This presents a dilemma for medicine with the pressure to discharge patients, and to save money for the system. The practice of decision-making is still quite elemental.
TRAPID-AMI is a prospective observational study supported by Roche and investigated more than 1,200 patients with acute chest pain during 2011-2014. The study was conducted in twelve institutions from nine countries and three continents, led by Professors Christian Mueller, University of Basel (Switzerland), and Bertil Lindahl, University of Uppsala (Sweden).
I have great respect for Mueller and Lindahl. This is a prospective observational study and does not carry the same weight as a randomized study. Moreover, there is nothing new in this, as you must know.
I think that the Roche hsTNT is the best method out there, but the study will not spur laboratories to switch from hsTnI. The only condition for such a decision would be performing the test in the ED, which might be the case here. POCT is not without problems.
Only in the last 5 years we have seen much confusion about interpreting the hsTnT and hsTnI. There is a sensitivity not achieved in earlier methods of the same proteins. However, there was a tradeoff in specificity and accuracy of diagnosis. It was great for cardiologists, and the measurement of a second assay in 3 hours was warranted. However, it was certainly reasonable to carry out the one hour study because patients arrive at the ED perhaps 6 hrs after onset. There was a time that while the CK-MB was increased and the second assay was in decline, The LD1 assay was needed for a late arrival because of placement on the curve. LD1 is no longer done, and patient awareness is much better than 15-20 years ago. I had a patent on an LD1 assay that could be done on a centrifugal fast analyzer using the forward reaction PYR–LAC, with NADH oxdation rather than LAC–PYR.
This study indicates that a validation of the suspect diagnosis can be done in 1 hour based on the increase in a shorter time span. It resolves some of the problem of hsTn’s. I’m not at all convinced that it is sufficient. I would have to see something more definitive.
There is consensus on the reclassification of Acute Coronary Syndrome into plaque rupture and not plaque rupture.
This creates a problem for relying on a so called “magic bullet” approach. It would certainly indicate that in order to classify correctly there has to be a minimum of two tests. All patients with CKD would fall into the not plaque rupture category. There are other patients who might have 50-60% narrowing and experience precordial symptoms, pressure, but without elevation. Are they very early AMI presentation, as my grandfather some 48 years ago?
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