Dobutamine Echocardiography in Patients With Aortic Stenosis and Left Ventricular Dysfunction

Clinical approach to severe aortic stenosis with low flow and low gradient

“…[3] Gradiyent, esas olarak, her dakikadaki atım-dan yani kardiyak debiden çok, her vurumdaki atıma yani atım hacmine bağlıdır ve atım hacmi, bu bağlamda en sık kullanılan parametredir. [3,[6][7][8][9] Bu hastalarda, düşük EF'nin iki nedeninden birincisi, sol ventrikül kütlesi ile ard yük arasındaki uyumsuzluktur. Kompansatuvar sol ventrikül küt-lesi beklenenden daha az, fakat miyosit fonksiyonu normaldir.…”

New concepts in valvular hemodynamics: Implications for diagnosis and treatment of aortic stenosis

“…This entity is generally characterized by the combination of an aortic valve EOA compatible with severe disease (ie, 1.0 cm 2 or less, or 0.6 cm 2 /m 2 or less when indexed for body surface area), a low transvalvular gradient (eg, mean gradient less than 40 mmHg), and a low ejection fraction (40% or less). Indeed, operative mortality for AVR in these patients is high, ranging between 8% and 33% depending on the study (37)(38)(39)(40)(41)(42)(43)(44)(45)(46). Moreover, this mode of presentation also represents a diagnostic challenge because at the outset, it is impossible to distinguish between patients having truly severe AS (TS AS) from those having pseudosevere AS (PS AS).…”

“…Typically, the valve EOA increases significantly with increasing flow in PS AS because the valve is semiflexible, whereas one expects no or minimal increase in EOA and marked increase in gradient when flow is increased in TS AS because the valve is rigid (Figure 3). Several criteria have been proposed in the literature to differentiate TS AS from PS AS, including: a peak stress mean gradient greater than 30 mmHg, a peak stress EOA 1.0 cm 2 or less or less than 1.2 cm 2 , depending on the study, and an absolute increase in EOA of less than 0.3 cm 2 during dobutamine stress echocardiography (DSE) (42,44,52,57,58). However, the changes in gradient and EOA during stress largely depend on the magnitude of flow augmentation achieved during DSE, which may vary considerably from one patient to another (52, 53,59,60).…”

Cardiovascular response to acute normovolaemic haemodilution in patients with severe aortic stenosis: assessment with transoesophageal echocardiography

“…However, haemodynamic improvement has been demonstrated following the administration of nitroprussiate or dobutamine, suggesting that decreased vascular resistance or reinforcement of contractility may recruit additional SV [12,13]. Hence, we hypothesise that lowering blood viscosity would facilitate venous return and cardiac filling, thereby increasing cardiac SV in response to ANH, without impairment in left ventricular (LV) function or elevation of transvalvular resistance.…”