Dr. Raphael Rosenhek,
The management of patients with low-flow low-gradient aortic stenosis presents challenges in the assessment as well as with regard to treatment options. Low-flow low-gradient aortic stenosis is characterized by a small calculated aortic valve area that would correspond to severe stenosis (<1.0 cm2) and a low transvalvular gradient (mean gradient smaller than 30 to 40 mmHg) in the presence of a depressed ventricular function.
PRO: P Pibarot (Quebec, CA) CONTRA:G Habib (Marseille, FR) One of the two debates focused on the usefulness of a low dose dobutamine echocardiography in this setting. The exam is helpful to differentiate between true severe aortic stenosis with consequently depressed left ventricular function and moderate aortic stenosis with an independent reason of left ventricular dysfunction such as ischaemic heart disease or a primary cardiomyopathy. Furthermore it allows the determination of contractile reserve, which is defined as an increase in stroke volume ≥20% during stress. While a preserved contractile reserve in the presence of true severe aortic stenosis is generally considered as a sign of lower surgical risk and improved survival after surgery, its absence should not lead to a systematical denial of surgery since postoperative improvement of left ventricular function has been described even in this group. An assessment of the extent of aortic valve calcification (which is an indirect marker of aortic stenosis severity) may prove useful in this setting and ultimately decision-making needs to consider the surgical risk and the overall morbidity of the patient.
PRO:J-L Monin (Creteil, FR) CONTRA: A A Pasquet (Brussels, BE) The other debate was centered on the entity of “paradoxical low flow aortic stenosis” which is also called low-flow low-gradient aortic stenosis despite a preserved left ventricular ejection fraction. These patients have a normal ejection fraction, but nevertheless a reduced stroke volume (a stroke volume index of ≤35ml/m2 has been proposed to define a low stroke volume). This situation may be observed in the presence of a severely hypertrophied left ventricle with a small left ventricular cavity, leading to a reduced stroke volume. Prior to diagnosing paradoxical low flow aortic stenosis, it is important that an underestimation of peak aortic jet velocity and a potential measurement error of left ventricular outflow tract area are ruled out, since both may lead to a similar measurement constellation. Since the currently available data on the topic is derived mainly from retrospective and very small prospective studies, it is too early to issue general recommendations for the treatment of these patients. The consideration of the symptomatic status and the confirmation that symptoms are related to aortic stenosis are essential. The use of transesophageal echocardiography or of computed tomography may prove helpful to assess the stenosis severity. Finally surgery may be proposed in selected patients after consideration of the operative risk.
Controversies in low-flow low-gradient aortic stenosis
Our mission: To reduce the burden of cardiovascular disease
© 2017 European Society of Cardiology. All rights reserved