High-Sensitivity Troponin T Plasma Levels in Patients With Aortic Stenosis (Tyrolean Aortic Stenosis Study-2)

Development of symptoms such as heart failure, syncope or angina pectoris is the well-established indication for valve operation in patients with severe aortic stenosis. However, many patients tend to misinterpretate or even ignore symptom onset, and irreversible myocardial dysfunction may occur. Measurement of aortic valve area by transthoracic echocardiography using the continuity equation is prone to methological mistakes, whereas transvalvular gradients are usually easy to quantify but may underestimate hemodynamic effects in the presence of low flow (stroke volume index below 35 ml/m2). All these shortcomings in clinical routine may be overcome by objectively and easily assessable parameters indicating advanced aortic stenosis. Severe aortic valve calcification is such a risk factor for worse prognosis. However, assessment of valve calcification by echocardiography is a subjective measurement and highly operator-dependent. Quantification of valve calcification by multi detector computed tomography is limited by exposure to radiation, availibilty and cost. A laboratory parameter already used in clinical routine would fullfill the requirements for such a risk stratification much better. Natriuretic peptides may be of interest in this context, but their plasma levels are strongly influenced by age, sex, concomitant arterial hypertension and/or renal dysfunction and volume status. Recently, high-sensitivity troponin plasma levels have been suggested to indicate ongoing myocardial fibrosis in aortic stenosis. A small study with 60 patients suggested that hs-TnT predicte the operative outcome of AS. We therefore set out to characterize the clinical value of minimally elevated troponin T plasma levels both in patients with asymptomatic and symtomatic aortic stenosis.