Hemodynamics in Primary Mitral Regurgitation
Support for and Challenges to the Conventional Wisdom
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- exercise physiology
- magnetic resonance imaging
- mitral valve insufficiency
The presence of symptoms in patients with severe primary mitral regurgitation (mitral prolapse/flail) carries a class I indication for intervention in current professional guidelines.1,2 However, symptoms may be underappreciated because of subconscious curtailment of physical activity, and it may be challenging to differentiate class I (no symptoms) from class II (mild symptoms), particularly when the symptoms are as nonspecific as dyspnea and fatigue—the hallmarks of symptomatic mitral regurgitation (MR). Moreover, it may be impossible to be confident that symptoms are attributable to MR when there are cardiac or pulmonary comorbidities. For these reasons, stress testing, typically with echocardiography, has become an increasingly important component of the evaluation and management of patients with MR.
See Article by Bakkestrøm et al
There is a substantial literature that speaks to the diagnostic and prognostic importance of stress echocardiography in patients with primary MR. Indeed, such testing provides information as to the patient’s functional and symptomatic status,3 inducibility,4 or worsening5 of MR, left ventricular contractile reserve,6,7 and right ventricular function.8 Noninvasively determined hemodynamics, notably pulmonary artery systolic pressure (PASP),9–11 have proven to be particularly important, in part, because resting PASP >50 mm Hg carries a class IIA indication for intervention (IIA) in American and European guidelines1,2 and exercise PASP ≥60 mm Hg carries a IIB indication for intervention in the European guidelines.2
The conventional wisdom has been that dyspnea is attributable to increased pulmonary capillary wedge pressure (PCWP), and indirect support for this has come from prior studies in which resting or exertional pulmonary hypertension (PASP >50 mm Hg or exertional PASP ≥60 mm Hg, respectively) has been linked to symptom onset in initially asymptomatic patients.9,11 Fatigue, which is less common, has been attributed to reduced forward flow. …