Contributed by Brian K. Theisen, MD and Octavia M. Peck-Palmer, PhD
This is a 41 year old male inmate with a past medical history reported from an outside hospital of hypertension and HIV (both of which the patient denied and subsequent HIV testing was negative). He presented to the prison physician with complaints of chest pain (6/10) and shortness of breath that began the prior evening while playing softball. At that time, his symptoms were also associated with nausea and vomiting so the patient attributed this combination of symptoms to acid reflux. An ECG done at the prison showed ST elevations and he was transferred to an outside hospital for further evaluation. Cardiac catheterization showed 100% proximal occlusion of the left anterior descending coronary artery (LAD). The patient was hemodynamically stable upon transfer to UPMC Presbyterian for further treatment.
On arrival, he was taken directly to the catheterization laboratory. The thrombosis was evacuated and three drug eluding stents were placed. Laboratory evaluation done at UPMC Presbyterian are shown in Table 1.
Table 1 illustrates that the Troponin I levels were elevated above the level of detection for the Beckman Coulter Access 2 instrument. In such situations, serial dilutions with Diluant A (which contains Bovine Serum Albumin - BSA) would allow for higher Troponin levels to be detected. However, due to evidence of incomplete recovery on dilution, Beckman Coulter no longer recommends dilution of samples as of December 21, 2011.
It is not uncommon to see elevations in Troponins and CK after percutaneous coronary intervention (PCI) procedures or open heart surgery due to continued loss of Myocardium (2); however, persistent elevations of Troponins can be indicative of continued myocardial ischemia. The American College of Cardiology (ACC) 2007 guidelines state that an increase in biomarkers greater than three times the 99th percentile after percutaneous coronary intervention is common with PCI related infarction (3). Therefore, to determine if the Troponin I levels were trending up or down a numerical result was needed. The samples were sent to UPMC Magee Women's Hospital which utilizes a different platform that allows for serial dilutions with Type A Water (Millipore). The results are reported in Table 2.
Table 2 illustrates that the values reported by the Beckman Coulter were consistent with the Siemes and upon dilution of the samples on the Beckman Coulter Instrument, the values were similar (data not shown).
DIAGNOSIS AND MANAGEMENT:
This patient met the diagnostic criteria for Myocardial Infarction with: elevated cardiac biomarkers, diagnostic ECG changes and chest pains. The Troponin and CK values reported from the Siemen's Dimension instrument at UPMC Magee Women's Hospital illustrate that the values were indeed greater than 100 and illustrated a downward trend following proximal stenting of the LAD. This illustrated that the patient was not experiencing a reinfarction. Follow-up studies illustrated a large area of akinesis including the anterior wall, septum and apex with elevated filling pressures but adequate cardiac output. It was concluded by the Cardiology team that the values were elevated above the detection limit due to prolonged myocardial ischemia and delayed presentation and intervention (>24 hours). The patient was started on Aspirin and Prasugrel (an antiplatelet ADP receptor inhibitor). He was not started on a statin initially due to elevated CK. His Troponin I level had trended down to 32.56 ng/mL on inpatient day four with corresponding CK-MB of 866 IU/L. He was discharged on aspirin, an ACE inhibitor, a beta blocker and a statin on inpatient day 5 and was to follow up with prison physician.