Author + information
- Konstantinos C. Siontis, MD,
- Vuyisile T. Nkomo, MD, MPH,
- Cristina Pislaru, MD,
- Maurice Enriquez-Sarano, MD,
- Patricia A. Pellikka, MD and
- Sorin V. Pislaru, MD, PhD∗ ()
- ↵∗Division of Cardiovascular Diseases, Mayo Clinic, 200 First Street Southwest, Rochester, Minnesota 55905.
Regurgitation across cardiac valves is driven by the presence and size of a regurgitant orifice and transvalvular pressure gradient. Thus, under normal circulatory conditions, aortic regurgitation is a diastolic phenomenon that occurs in the setting of an incompetent aortic valve when pressure in the aorta exceeds that of the left ventricle. The paradoxical phenomenon of systolic aortic regurgitation (SAR) has been previously identified in patients with arrhythmias, after palliative operations for congenital heart disease, and in patients with left ventricular assist devices (LVADs) (1–3).
Herein, we describe a series of 3 cases of SAR in the setting of continuous flow LVAD (2 patients with the HeartMate II device [Thoratec Corporation, Pleasanton, California]), and 1 patient with a HeartWare device (HeartWare International Inc., Framingham, Massachusetts). Parasternal echocardiographic imaging in the first patient demonstrated trivial systolic aortic valve movement while purely SAR appears during every heart cycle (Fig. 1A, Online Video 1). There was no regurgitation during diastole as evidenced by both parasternal color M-mode (Fig. 1B, arrows) and pulsed-wave Doppler of the outflow tract just below the aortic valve plane (Fig. 1C, arrows showing SAR but not diastolic aortic regurgitation). In the second patient, aortic regurgitation was trivial but continuous (Fig. 1D, Online Video 2); color M-mode captured only SAR (Fig. 1E, arrows). There was continuous regurgitation on pulsed-wave Doppler, with reduced gradient (lower velocity) but increased Doppler density in late systole (Fig. 1F, arrows). Finally, the third patient had continuous aortic regurgitation, with significant increase in aortic regurgitation vena contracta during systole (Figs. 1G and 1H, Online Video 3).
SAR occurred in all 3 patients long after device implantation (130, 134, and 438 days, respectively). There was no evidence of device malfunction according to clinical (no change in effort ability) and echocardiographic (neutral position of the interventricular septum, laminar flow with normal velocities in inflow and outflow cannulae) criteria. Cardiac output (estimated from the right ventricular outflow tract diameter and time-velocity integral) was at the low end of normal (4.8, 4.9, and 5.3 l/min, respectively) and was unchanged compared with previous echocardiographic studies.
Presence of SAR in this series of patients with LVADs offers unique insights into valvular physiology. In all patients, systolic increase in left ventricular pressure was demonstrated by mitral valve closure (Online Videos 4, 5 and 6). Conversely, aortic systolic pressure clearly exceeded ventricular pressure, a fact demonstrated by the presence of SAR at the time of systolic opening of the aortic valve. Given that left ventricular pressure cannot induce conventional “valvular opening,” a mechanism other than pressure gradient must be involved.
The systolic increase in left ventricular pressure above the level of left atrial pressure leads to posterior displacement of the aorto-mitral curtain, with conformational changes of left ventricular outflow tract from an oval (in diastole) to a more circular shape in systole (Fig. 1I). We hypothesized that these systolic conformational changes in the left ventricular outflow tract, aortic annulus, and possibly the aortic root are responsible for valvular opening despite the higher aortic pressure. Another possibility is elastic recoil of the aortic valve leaflets and reduced leaflet coaptation on the background of reduced transvalvular pressure gradient in systole. Elastic properties of the aortic root may also play a role.
These observations have significant clinical implications in the era of expanding use of transcatheter aortic valve replacement and LVAD implantations. Amid ongoing efforts to better characterize the aortic anatomy pre- and intraoperatively, taking into account the dynamic conformational changes occurring throughout the cardiac cycle could lead to more appropriate patient and prosthetic valve selection, and ultimately improve procedural success rates and clinical outcomes.
For supplemental videos and their legends, please see the online version of this article.
- American College of Cardiology Foundation
- Saura D.,
- Gonzalez J.,
- de la Morena G.,
- Valdes-Chavarri M.
- Cowger J.,
- Pagani F.D.,
- Haft J.W.,
- Romano M.A.,
- Aaronson K.D.,
- Kolias T.J.