Prognostic Value of High-Sensitivity Troponin-T to Identify Patients at Risk of Left Ventricular Graft Dysfunction After Heart Transplantation.

Primary graft dysfunction after heart transplantation (HTx) has a very high mortality rate, especially if the left ventricle (PGD-LV) is involved. Early diagnosis is important to select the appropriate therapy to improve prognosis. The value of high-sensitivity troponin T (HS-TNT) measurement obtained at patient arrival at the intensive care unit was analyzed in 71 HTx patients. Mild or moderate PGD-LV was defined by hemodynamic compromise with one of the following criteria: left ventricular ejection fraction <40%, hemodynamic compromise with right atrial pressure >15 mm Hg, pulmonary capillary wedge pressure >20 mm Hg, cardiac index <2.0 L/min/m2, hypotension (mean arterial pressure <70 mm Hg), and need for high-dose inotropes (inotrope score >10) or newly placed intra-aortic balloon pump. The mean recipient age was 54 ± 12 years (73% men), and donor age was 47 ± 11 years. Ischemic time was 200 ± 51 minutes, and coronary bypass time was 122 ± 31 minutes. Nine (13%) HTx patients were diagnosed with PGD-LV post-HTx, 8 with biventricular dysfunction. Four patients died, 2 with PGD-LV (22%) and 2 without PGD (4%). Mean HS-TNT before HTx was 158 ± 565 ng/L, and post-HT was 1621 ± 1269 ng/L. The area under the curve (receiver-operator characteristic) of HS-TNT to detect patients at risk of PGD-LV was 0.860 (P < .003). A cutoff value of HS-TNT >2000 ng/L had a sensitivity of 75% and specificity of 87% to identify patients at risk of PGD-LV. Multivariate analysis identified HS-TNT >2000 ng/L (P < .02) and coronary bypass-time (P < .01) as independent predictors of PGD-LV. HS-TNT >2000 ng/L at intensive care admission after HT and prolonged coronary bypass time were the most powerful predictors of PGD-LV. HS-TNT may be helpful for early detection of HTx patients at risk of PGD-LV.

Cost-Effectiveness of Highly Sensitive Cardiac Troponin T to Rule Out Acute Rejection After Heart Transplantation.

BACKGROUND: Endomyocardial biopsy (EMB) remains the gold standard for detecting acute rejection (AR) after heart transplantation (HTx). Non-invasive detection of AR thus far remains a challenge. Several studies have demonstrated that highly sensitive cardiac troponin T (hs-cTnT) concentrations have a low positive predictive value for diagnosing AR. Nevertheless, hs-cTnT proved to be useful for ruling out AR after HTx. An hs-cTnT concentration <17 ng/L, a value close to that used for rule-in or rule-out myocardial infarction, was associated with a 100% negative predictive value of AR. However, the cost-effectiveness of a strategy with the use of hs-cTnT for ruling out AR in HTx patients remains to be proven. METHODS: The cost-effectiveness of hs-cTnT determination for ruling out AR was assessed, comparing the costs of hs-cTnT measurements in 305 blood samples obtained at the time of EMB. Eighteen samples were excluded because the EMB was not assessable. RESULTS: Hs-cTnT determination cost 16.00€ per sample, whereas EMB cost 1752.00€ per biopsy; cost estimations included direct and indirect (30%) charges. Thirty-nine (13.6%) of the 287 blood samples presented hs-cTnT concentrations <17 ng/L; in none of them was an AR >2R degree found in the EMB. The cost of the assessment in the 287 blood samples and biopsies was of 4592.00€ for hs-cTnT and 502,824.00€ for EMB. Hs-cTnT systematic measurement would have avoided 39 EMB, with a saving of 68,328.00€, which represents the 13.5% of the total budget expended in these cases. CONCLUSIONS: The use of hs-cTnT values to rule out the need of EMB for AR diagnosis after HTx appears to be a cost-effective procedure.