Redo Valve-Sparing Root Replacement for Delayed Cusp Derangement From Ventricular Septal Defect

A 3D-Printed Externally Adjustable Symmetrically Extensible (EASE) Aortic Annuloplasty Ring for Root Repair and Aortic Valve Regurgitation

PURPOSE

The valve-sparing aortic root replacement (VSARR) procedure was developed to preserve the aortic valve apparatus to replace aneurysmal aortic roots with synthetic grafts and to eliminate associated aortic regurgitation (AR). However, residual post-repair AR is not uncommon and has been found to be associated with recurrent AR and future reoperation.

METHODS

We designed and manufactured a 3D-printed, external adjustable symmetrically extensible (EASE) aortic annuloplasty ring that can symmetrically reduce the aortic annulus diameter via a radial constriction, compliant mechanism. An ex vivo porcine VSARR model with annular dilation and AR was developed (n = 4) and used for hemodynamic, echocardiography, and high-speed videography data collection.

RESULTS

After ring annuloplasty repair using the EASE aortic ring, the regurgitant fraction decreased from 23.6 ± 6.9% from the VSARR model to 7.4 ± 5.6% (p = 0.05), which was similar to that measured from baseline with a regurgitant fraction of 10.2 ± 3.9% (p = 0.34). The leaflet coaptation height after annuloplasty repair also significantly increased from that measured in VSARR model (0.4 ± 0.1 cm) to 0.9 ± 0.1 cm (p = 0.0004), a level similar to that measured in baseline (1.1 ± 0.1 cm, p = 0.28).

CONCLUSION

Using an ex vivo VSARR model, the EASE ring successfully reduced AR by reducing the annular diameter and improving leaflet coaptation. With its broad applicability and ease of use, this device has the potential to have a significant impact on patients suffering worldwide from AR due to root aneurysms.

Right Ventricular Outflow Tract Obstruction in Adults: A Systematic Review and Meta-analysis

Background

Right ventricular outflow tract obstruction (RVOTO) is a cause of hemodynamic instability that can occur in several situations, including cardiac surgery, lung transplantation, and thoracic surgery, and in critically ill patients. The timely diagnosis of RVOTO is important because it requires specific considerations, including the adverse effects of positive inotropes, and depending on the etiology, the requirement for urgent surgical intervention.

Methods

The objective of this systematic review and meta-analysis was to determine the prevalence of RVOTO in adult patients, and the distribution of all reported cases by etiology.

Results

Of 233 available reports, there were 229 case reports or series, and 4 retrospective cohort studies, with one study also reporting a prospective cohort. Of 291 reported cases of RVOTO, 61 (21%) were congenital, 56 (19%) were iatrogenic, and 174 (60%) were neither congenital nor iatrogenic (including intracardiac tumour). The mechanism of RVOTO was an intrinsic obstruction in 169 cases (58%), and an extrinsic obstruction in 122 cases (42%). A mechanical obstruction causing RVOTO was present in 262 cases (90%), and 29 cases of dynamic RVOTO (10%) were reported. In the 5 included cohorts, with a total of 1122 patients, the overall prevalence was estimated to be 4.0% (1%-9%).

Conclusions

RVOTO, though rare, remains clinically important, and therefore, multicentre studies are warranted to better understand the prevalence, causes, and consequences of RVOTO.

A Novel Aortic Regurgitation Model from Cusp Prolapse with Hemodynamic Validation Using an Ex Vivo Left Heart Simulator

Although ex vivo simulation is a valuable tool for surgical optimization, a disease model that mimics human aortic regurgitation (AR) from cusp prolapse is needed to accurately examine valve biomechanics. To simulate AR, four porcine aortic valves were explanted, and the commissure between the two largest leaflets was detached and re-implanted 5 mm lower to induce cusp prolapse. Four additional valves were tested in their native state as controls. All valves were tested in a heart simulator while hemodynamics, high-speed videography, and echocardiography data were collected. Our AR model successfully reproduced cusp prolapse with significant increase in regurgitant volume compared with that of the controls (23.2 ± 8.9 versus 2.8 ± 1.6 ml, p = 0.017). Hemodynamics data confirmed the simulation of physiologic disease conditions. Echocardiography and color flow mapping demonstrated the presence of mild to moderate eccentric regurgitation in our AR model. This novel AR model has enormous potential in the evaluation of valve biomechanics and surgical repair techniques. Graphical Abstract.