The hemodynamic effects of acute aortic regurgitation into a stiffened left ventricle resulting from chronic aortic stenosis

Abstract

Acute aortic regurgitation (AR) post-chronic aortic stenosis is a prevalent phenomenon occurring in patients who undergo transcatheter aortic valve replacement (TAVR) surgery. The objective of this work was to characterize the effects of left ventricular diastolic stiffness (LVDS) and AR severity on LV performance. Three LVDS models were inserted into a physiological left heart simulator. AR severity was parametrically varied through four levels (ranging from trace to moderate) and compared with a competent aortic valve. Hemodynamic metrics such as average diastolic pressures (DP) and reduction in transmitral flow were measured. AR index was calculated as a function of AR severity and LVDS, and the work required to make up for lost volume due to AR was estimated. In the presence of trace AR, higher LVDS had up to a threefold reduction in transmitral flow (13% compared with 3.5%) and a significant increase in DP (2-fold). The AR index ranged from ∼42 to 16 (no AR to moderate AR), with stiffer LVs having lower values. To compensate for lost volume due to AR, the low, medium, and high LVDS models were found to require 5.1, 5.5, and 6.6 times more work, respectively. This work shows that the LVDS has a significant effect on the LV performance in the presence of AR. Therefore, the LVDS of potential TAVR patients should be assessed to gain an initial indication of their ability to tolerate post-procedural AR.

Incidental Perforation of Aortic Valve Leaflet Found on Presentation of Cardiogenic Shock

“…Furthermore, pulmonary edema can develop because of an increase in diastolic volume in a normal-sized LV secondary to the regurgitant flow from the perforate aortic valve. The rapid increase in LV diastolic pressure results in both increased left atrial and pulmonary venous pressures, resulting in pulmonary edema [ 5 ].…”

“…This acute decrease in cardiac output is known as cardiogenic shock, and on a physical exam, this can be seen as hypotension and tachycardia. Furthermore, pulmonary edema can develop because the increased volume from the regurgitant flow within a normal-sized LV causes a rapid increase in LV diastolic pressure that propagates to both increased left atrial and pulmonary venous pressures [ 5 ].…”

Acute native aortic regurgitation: clinical presentation, diagnosis and management

“…This propagates upstream leading to elevated left atrial pressure, elevated pulmonary artery (PA) pressure and eventual right ventricular pressure overload and systolic dysfunction. These perturbations can be further exacerbated by pre-existing conditions, such as a stiff LV seen with hypertension or aortic stenosis 20. Acute compensatory mechanisms include increased adrenergic tone, resulting in tachycardia and hypercontractility 21.…”

Left Ventricular Diastolic Dysfunction and Transcatheter Aortic Valve Replacement Outcomes: A Review

“…The difference in impact of various degrees of PVR on TAVR outcome originates from baseline LVDD. In patients with severe LVDD, even trace PVR can increase LVEDP and deteriorate heart function, increasing mortality, but those with more compliant LV may better tolerate higher degrees of PVL [ 40 ]. Post-TAVR PVR was found to be related to device size and form, patient native valve and LV outflow tract anatomy, and technical issues [ 22 ].…”

“…1). Controversial studies were reported about the impact of different degrees of PVR on outcomes after TAVR [31, 40]. Sato et al found increased LVEDP among patients who died within 1 year after TAVR, and presence of post-TAVR aortic regurgitation was the only independent predictor of mortality at 1 year [20].…”