Post-operative ventricular flow dynamics following atrioventricular valve surgical and device therapies: A review

Long-term cardiac remodeling associated with heart failure following left-ventricular valve replacement surgery: A retrospective study

To investigate long-term cardiac remodeling and prognosis of patients post-left-ventricular valve replacement, and explored related risk factors of heart failure and management strategies. Retrospective cohort of patients with left-ventricular valve replacement between 2005 and 2007. Major adverse cardiac events were recorded, including death, hospitalization, stroke, and New York Heart Association (NYHA) functional classifications. Cardiac remodeling was assessed by comparing pre-operative, post-operative, and follow-up echocardiographic images. (1).. Two hundred fifty-seven patients who received left-ventricular mitral, aortic, or double-valve replacement surgery were followed up for 10.4 ± 1.5 years with an all-cause mortality rate 18.7% and an incidence of heart failure that significantly restricted daily life (NYHA III or IV) 21.3%. (2).. There were no significant differences in classic cardiac-remodeling variables between baseline and long-term follow-up, such as left-ventricular diameter (47.9 ± 8.3 vs 49.9 ± 8.0 mm, P = .14) and left-ventricular ejection fraction (58.6 ± 9.6% vs 57.0 ± 10.3%, P = .34), whereas there were significant differences in terms of left-atrial anteroposterior diameter (LA) (39.7 ± 9.5 vs 49.0 ± 14.3 mm, P < .001) and tricuspid regurgitation (TR) (1.4 ± 1.0 vs 2.2 ± 1.2, P < .001). Multivariable logistic regression analysis showed that LA ≥ 50 mm (P = .011) and more than moderate tricuspid regurgitation (TR > 2) (P = .012) were associated with poor prognoses for long-term consequences of heart failure. Both LA and TR progressed with the length of time after surgery. LA enlargement and TR after left-ventricular valve replacement surgery were time-dependent events, which represented cardiac remodeling and were closely related to post-operative long-term consequences of heart failure. It is important to be cognizant of and to explore long-term preventive and treatment strategies for adverse cardiac events in patients following left-ventricular valve replacement.

Impact of prosthetic mitral valve orientation on the ventricular flow field: Comparison using patient-specific computational fluid dynamics

Significant mitral valve regurgitation creates progressive adverse remodeling of the left ventricle (LV). Replacement of the failing valve with a prosthesis generally improves patient outcomes but leaves the patient with non-physiological intracardiac flow patterns that might contribute to their future risk of thrombus formation and embolism. It has been suggested that the angular orientation of the implanted valve might modify the postoperative distortion of the intraventricular flow field. In this study, we investigated the effect of prosthetic valve orientation on LV flow patterns by using heart geometry from a patient with LV dysfunction and a competent native mitral valve to calculate intracardiac flow fields with computational fluid dynamics (CFD). Results were validated using in vivo 4D Flow MRI. The computed flow fields were compared to calculations following virtual implantation of a mechanical heart valve oriented in four different angles to assess the effect of leaflet position. Flow patterns were visualized in long- and short-axes and quantified with flow component analysis. In comparison to a native valve, valve implantation increased the proportion of the mitral inflow remaining in the basal region and further increased the residual volume in the apical area. Only slight changes due to valve orientation were observed. Using our numerical framework, we demonstrated quantitative changes in left ventricular blood flow due to prosthetic mitral replacement. This framework may be used to improve design of prosthetic heart valves and implantation procedures to minimize the potential for apical flow stasis, and potentially assist personalized treatment planning.

Treatment of isolated tricuspid regurgitation in 2020: an update

Tricuspid valve regurgitation is an insidious pathology that is associated with increased mortality if left untreated. Conversely, surgical correction of tricuspid regurgitation is burdened by poor outcomes, especially when right ventricular dysfunction, kidney disease, or liver disease occur. There is, therefore, increasing interest in transcatheter approaches as an alternative to surgery in patients at high or prohibitive surgical risk. The development of percutaneous devices to treat tricuspid regurgitation has several technical challenges, mainly because of the complexity of valve anatomy, thus requiring accurate patient selection. Here we review the currently available transcatheter approaches to treat severe tricuspid regurgitation.

Ventricular vortex loss analysis due to various tricuspid valve repair techniques: an ex vivo study

The deteriorating nature of severe functional tricuspid regurgitation (FTR) has led to the heightened interest in this pathology. However, therapies are heterogeneous and an ideal technique is uncertain. The hemodynamic impact on the cardiac chamber following therapeutic repairs has not been well studied, while its analysis could be used to predict the treatment success. In this study, the hemodynamics of the right ventricle (RV) after 1) clover edge-to-edge tricuspid repair, and 2) double orifice tricuspid repair was evaluated in three right heart models using an ex vivo pulsatile platform emulating severe FTR with the aid of stereoscopic particle image velocimetry. Although all repairs substantially reduced tricuspid regurgitant area, they resulted in a more than 50% reduction in diastolic tricuspid valve (TV) opening area. Splitting the TV orifice into multiple smaller orifices by both repairs eliminated the ring-shaped vortical structure inside the RV observed in FTR cases. Postrepair RV domain was mostly occupied with irregular vortical features and isolated vortex residuals. Moreover, vortical features varied among repair samples, indicating enhanced sensitivity of RV flow to postrepair TV morphology. Compared with clover repair, double orifice subjected the RV to enhanced swirling motions and exposed more regions to vortical motions, potentially indicating better rinsing and lower risk of mural thrombus formation. Double orifice repair increased the levels of RV mean kinetic energy and viscous energy loss than those observed in clover repair, although the impact of these on the cardiac efficiency remains unclear. These preliminary insights could be used to improve future treatment design and planning.NEW & NOTEWORTHY While clover and double orifice tricuspid repairs markedly improved leaflet coaptation, they substantially reduced diastolic tricuspid opening area. Postrepair right ventricle (RV) exhibited specific hemodynamic traits, including the loss of ring-shaped vortical structure and the enhanced sensitivity of RV flow to postrepair tricuspid valve morphology. Compared with clover technique, double orifice repair led to higher swirling motions in the RV domain, which could indicate lower risk of mural thrombus formation.

Ex vivo assessment of bicuspidization repair in treating severe functional tricuspid regurgitation: a stereo-scopic PIV study

There has been a resurgence of interest in the treatment of severe functional tricuspid regurgitation (FTR) due to the awareness of its poor outcomes and potential percutaneous therapies. Kay bicuspidization has been adapted in percutaneous therapies but its clinical outcome remains uncertain. The present study evaluates the efficacy of Kay repair in a novel ex vivo pulsatile system. Porcine tricuspid valve (TV) (n = 3) was extracted and incorporated into a patient-specific silicon right ventricle (RV) emulating severe FTR, on which Kay repair was subsequently performed. TV area metrics and RV hemodynamic assessment by means of stereo-scopic particle image velocimetry were quantified in both FTR and post-repair conditions. Bicuspidization led to significant increase in cardiac output although the overall increment due to this approach alone was generally small, possibly due to existence of residual TR and the large reduction in TV opening area. Kinetic energy and viscous loss levels were increased post-repair, especially during diastolic filling. Main vortex structures generally maintained post-procedural. However, there was enhanced swirling motion in larger RV domain. Although this might reduce mural-thrombus risk, the relatively more complex vortex phenomenon likely resulted in elevated viscous loss observed and may potentially impact long-term adaptation. The RV hemodynamic alteration after tricuspid repair could be used to predict the success of these future transcatheter solutions.