Early Left and Right Ventricular Response to Aortic Valve Replacement

Abstract

Background The immediate effect of aortic valve replacement (AVR) for aortic stenosis on perioperative myocardial function is unclear. Left ventricular (LV) function may be impaired by cardioplegia-induced myocardial arrest and ischemia-reperfusion injury, especially in patients with LV hypertrophy. Alternatively, LV function may improve when afterload is reduced following AVR. The right ventricle (RV), however, experiences cardioplegic arrest without benefiting from improved loading conditions. Which of these effects on myocardial function dominate in patients undergoing AVR for aortic stenosis has not been thoroughly explored. Our primary objective thus to characterize the effect of intraoperative events on LV function during AVR using echocardiographic measures of myocardial deformation. Secondarily, we evaluated RV function. Methods In this supplementary analysis of 100 patients enrolled in a clinical trial (NCT01187329), 97 patients underwent AVR for aortic stenosis. Of these patients, 95 had a standardized intraoperative transesophageal echocardiographic examination of systolic and diastolic function performed before surgical incision and repeated after chest closure. Echocardiographic images were analyzed off-line for global longitudinal myocardial strain and strain rate using 2-dimensional speckle-tracking echocardiography. Myocardial deformation assessed at the beginning of surgery was compared with the end of surgery using paired t-tests corrected for multiple comparisons. Results LV volumes and arterial blood pressure decreased, and heart rate increased at the end of surgery. Echocardiographic images were acceptable for analysis in 72 patients for LV strain, 67 for LV strain rate, and 54 for RV strain and strain rate. In 72 patients with LV strain images, 9 patients required epinephrine, 22 required norepinephrine, and 2 required both at the end of surgery. LV strain did not change at the end of surgery compared with the beginning of surgery [difference: 0.7 (97.6%CI: 0.2, 1.5)%; P =0.07] while LV systolic strain rate improved (became more negative) [−0.3 (−0.4, −0.2) sec−1; P<0.001]. In contrast, RV systolic strain worsened (became less negative) at the end of surgery [difference: 4.6 (3.1, 6.0)%; P< 0.001] although RV systolic strain rate was unchanged [0.0 (97.6% CI: −0.1, 0.1); P = 0.83]. Conclusion LV function improved after replacement of a stenotic aortic valve demonstrated by improved longitudinal strain rate. In contrast, RV function, assessed by longitudinal strain, was reduced.

Regional Versus Global Measurements of Right Ventricular Strain Performed in the Operating Room With Transesophageal Echocardiography

“…This is particularly important in cardiac surgery patients in whom numerous insults to the right ventricle occur over time (eg, poor preservation with cardioplegia, air, increased pulmonary vascular resistance after CPB), and RV function must be reassessed continually during the prebypass and postbypass periods. 26,27 It is important to note that even though the authors of the present study found both regional and global strain measurements to be highly sensitive for RV dysfunction, the specificity was only moderate. Consequently, a normal RV strain measurement likely rules out dysfunction but an abnormal RV strain sometimes is seen in the setting of a normal RV EF.…”

Detection of intraoperative myocardial dysfunction by accelerometer during aortic valve replacement

“…The basal longitudinal motion is reduced, whereas apical circumferential motion increases [19,20]. The most striking effect after surgical and transcatheter AVR is increased basal longitudinal motion [21][22][23]. The apical region where the accelerometer was placed is less affected [18,21,24].…”

Right ventricular mechanics in patients with aortic stenosis and preserved ejection fraction: Is arterial hypertension a new player in the game?

“…However, studies have shown that its structure and function is very important in patients with congenital heart disease and pulmonary hypertension, but afterward, the important role of RV remodeling has been proved in the patients with heart failure, heart transplantation, cardiomyopathies, and valvular heart disease . The influence of aortic stenosis (AS) and particularly of AS severity on RV remodeling is still debatable, and the data are scarce . Recently, several studies regarding the prognostic importance of RV structure and function in AS patients after surgical replacement or catheter aortic valve implantation have been published …”

“…The influence of aortic stenosis (AS) and particularly of AS severity on RV remodeling is still debatable, and the data are scarce . Recently, several studies regarding the prognostic importance of RV structure and function in AS patients after surgical replacement or catheter aortic valve implantation have been published …”