Ozaki Procedure Research Articles

Assessing aortic morphology post aortic valve replacement using unsupervised hierarchical clustering and statistical shape modelling

Abstract Introduction There are different surgical procedures used to treat aortic valve disease such as aortic valve replacement (AVR), the Ozaki procedure, the Ross procedure, and the valve-sparing procedure. There may be postoperative side effects associated with aortic morphology. Computational analyses that assess morphology are thus necessary in such scenario. Statistical shape modelling is used to assess three-dimensional morphology, discover unique shape features, create mean shapes, and create shape modes that display morphological variability. Hierarchical cluster analysis is a machine learning method used to classify a population into subgroups. Both of these statistical methods were applied to aortic valve replacement patients to evaluate morphological variability after aortic valve replacement (AVR) surgery. Purpose The purpose of this study is to assess the aortic morphology of AVR patients, identify morphological differences between different surgical procedures, identify subgroups postoperatively using statistical shape modelling and hierarchical cluster analysis, and assessing possible correlations between the resultant clusters and function i.e. ejection fraction. Methods Computed tomography and cardiac magnetic resonance images were used to reconstruct aortas into 3D models using segmentation and 3D reconstruction software. For each patient, two models were created (i.e. ascending aorta only and aorta including the arch and the descending aorta). N=35 patients were included in the study. Statistical shape analysis was run to create templates and shape modes. Statistical environment and language software was used to run hierarchical cluster analysis. Results Overall, the hierarchical cluster analysis did not classify the aortas based on type of surgery, but most patients in the Ross group demonstrated morphological differences from the other surgical groups and many of the aortas belonging to the Ross group were clustered together in both clustering analyses. No significant differences between clusters were seen (p=0.47 for ascending, p=0.19 for whole aorta). No correlation was found between clusters and ejection fraction (p=0.75, r2<0.01), possibly indicating that post-AVR aortic morphology in this sample does not reflect overt functional changes. Conclusion Both statistical shape modelling and hierarchical cluster analyses were successful in assessing morphological variability and identifying subgroups in this population. This framework could therefore be extended to larger samples to inform on surgical decision-making allowing surgeons to choose the appropriate surgery for the patient or design prosthetic valves that are more customised to the patient’s anatomy.Cluster-Ejection Fraction Correlation

Analysis of Fluid-Structure Interaction Mechanisms for a Native Aortic Valve, Patient-Specific Ozaki Procedure, and a Bioprosthetic Valve.

The Ozaki procedure is a surgical technique which avoids to implant foreign aortic valve prostheses in human heart, using the patient's own pericardium. Although this approach has well-identified benefits, it is still a topic of debate in the cardiac surgical community, which prevents its larger use to treat valve pathologies. This is linked to the actual lack of knowledge regarding the dynamics of tissue deformations and surrounding blood flow for this autograft pericardial valve. So far, there is no numerical study examining the coupling between the blood flow characteristics and the Ozaki leaflets dynamics. To fill this gap, we propose here a comprehensive comparison of various performance criteria between a healthy native valve, its pericardium-based counterpart, and a bioprosthetic solution, this is done using a three-dimensional fluid-structure interaction solver. Our findings reveal similar physiological dynamics between the valves but with the emergence of fluttering for the Ozaki leaflets and higher velocity and wall shear stress for the bioprosthetic heart valve.

Short-term outcomes of the Tiara bioprosthesis and the Ozaki procedure comparison: a multicenter retrospective study with propensity score analysis

Short-term outcomes of the Tiara bioprosthesis and the Ozaki procedure comparison: a multicenter retrospective study with propensity score analysis

Concomitant Ozaki procedure and septal myectomy in patients with severe aortic stenosis

Concomitant Ozaki procedure and septal myectomy in patients with severe aortic stenosis

Choice of valve substitutes.

Infective endocarditis often necessitates surgical intervention, and the choice of valve substitute remains a topic of controversy and highly debatable due to the wide range of available options and recent technical advancements. This manuscript reviews the different valve substitutes in the context of infective endocarditis, including mechanical and bioprosthetic valves, homografts, xenografts, and tissue-engineered valves. The patient's age, sex, demographic location, intellectual quotient, comorbidities, available options, and the experience of the surgeon should all be taken into consideration while choosing the best valve substitute for that individual. While valve repair and reconstruction are preferred whenever feasible, valve replacement may be the only option in certain cases. The choice between mechanical and bioprosthetic valves should be guided by standard criteria such as age, sex, expected lifespan, associated comorbidities, and anticipated adherence to anticoagulation therapy and accessibility of medical facilities for follow-up. For patients with severe chronic illness or a history of intracranial bleeding or associated hematological disorders, the use of mechanical prostheses may be avoided. Homografts and bioprosthetic valves provide an alternative to mechanical valves, thereby decreasing the necessity for lifelong anticoagulation after surgery and diminishing the likelihood of bleeding complications. The manuscript also discusses specific valve substitutes for different heart valves (aortic, mitral, pulmonary, tricuspid positions) and highlights emerging techniques such as the aortic valve neocuspidization (Ozaki procedure) and tissue-engineered valves. Ultimately, the ideal valve substitute in IE should be evidence based on a comprehensive elucidation of clinical condition of the patient and available options.

Outcomes post Ozaki procedure among children with aortic valve disease at Jakaya Kikwete Cardiac Institute, Dar es Salaam, Tanzania: a retrospective descriptive study

BackgroundAortic valve reconstruction using glutaraldehyde-treated autologous pericardium, also called Ozaki procedure, is a surgical procedure for patients with aortic valve disease. Gratifying results have been reported in adult patients, however, limited published data is available in paediatric population. This study looked at clinical characteristics and early outcomes of children who underwent Ozaki procedure at our Institute.MethodsThis was a retrospective descriptive study conducted on children who underwent aortic valve reconstruction at Jakaya Kikwete Cardiac Institute (JKCI) from January 2019 through December 2022. Medical records of these children were reviewed to extract data on demographics, clinical characteristics, redo surgical interventions and survival.ResultsA total of 10 children underwent Ozaki procedure during the study period. Eight children had severe aortic regurgitation while 2 had severe aortic stenosis preoperatively. All children had either none or trivial aortic regurgitation immediately after surgery. None of them had redone operations throughout the follow-up period. There was no in-hospital mortality, however, one child died one-year after surgery. The mean follow-up period was 1.6 years with the longest follow-up time of 4 years.ConclusionOzaki procedure showed encouraging early results among children with aortic valve disease who underwent surgical repair by this technique. Future studies with larger sample sizes and longer follow up periods to evaluate long-term results in this population are recommended.

Aortic valve hemodynamic characteristics after the Ozaki procedure according to echocardiography: a multicenter retrospective study

Aim. To evaluate the aortic valve (AV) hemodynamic characteristics after the Ozaki procedure according to echocardiography.Material and methods. The retrospective multicenter study included 277 patients with AV defects who were operated on from January 2017 to June 2022 in five centers in Russia. After the Ozaki procedure, the following endpoints were assessed: immediate echocardiographic results (peak AV gradient, mean AV gradient, AV effective orifice area, aortic regurgitation grade), mid-term clinical (three-year survival rate, three-year freedom from reoperation, three-year freedom from grade ≤2 aortic regurgitation) and echocardiographic results (peak and mean AV gradient, AV effective orifice area, aortic regurgitation grade, AV calcification severity). The median follow-up period was 23 (13-32) months. The mean echocardiography follow-up period was 21±10 months.Results. During the treatment, a decrease in the peak AV gradient was observed from 74±30 mm Hg before surgery up to 12 (8-16) mm Hg one week after surgery, which remained in the mid-term period — 12 (9-15) mm Hg. There was also a decrease in the mean gradient from 40 (27-53) mm Hg before surgery up to 6 (4-8) mm Hg one week after surgery. By the mid-term period, the mean gradient was 6 (4-8) mm Hg. The AV effective orifice area increased from 1 (1-1) cm2 to 2 (2-2) cm2 in the mid-term follow-up period. Three-year survival rate was 90,2%, freedom from reoperation was 95%, freedom from grade ³2 aortic regurgitation was 88%, and no patient had AV calcification.Conclusion. The Ozaki procedure in patients with AV defects has good immediate and mid-term hemodynamic parameters according to echocardiography. However, there remains a need for large randomized controlled trials comparing Ozaki procedure with biological AV replacement.

Midterm Outcomes After Aortic Valve Neocuspidization (Ozaki Procedure) in Adults

BackgroundTrileaflet aortic valve neocuspidization (AVN) using autologous pericardium (Ozaki procedure) is an emerging surgical treatment option for aortic valve diseases. Although excellent results have been reported from Japan, data pertaining to its use in the United States are sparse. MethodsAll adult patients who underwent AVN (AVN group) or surgical aortic valve replacement (SAVR) with a bioprosthetic valve (SAVR group) between 2015 and 2022 were identified. Propensity score matching was used to adjust the baseline characteristics between the 2 groups. ResultsA total of 101 patients underwent AVN, and 1816 patients underwent SAVR with a bioprosthetic valve. None in the AVN group required conversion to SAVR. Before matching, mean age in the AVN group was 68.5 ± 8.8 years, and 56 patients (55.4%) underwent concomitant procedures. Preoperatively, 3 (3%) had endocarditis. Bicuspid valve was observed in 38 (38.4%). None died at 30 days in the AVN group. The median follow-up duration was 3.2 years. After propensity score matching, the expected survival and freedom from at least moderate aortic regurgitation at 5 years was 91.7% ± 3.1% and 97.6% ± 1.7%, respectively. Propensity score matching yielded 77 patients in each group. The Kaplan-Meier curve demonstrated equivalent survival at 5 years between the 2 groups (P = .95). Additionally, freedom from at least moderate aortic regurgitation was comparable at 5 years (P = .23). ConclusionsAVN can be safely performed for a variety of aortic valve diseases, with or without concomitant operations. AVN demonstrated similar midterm outcomes compared with SAVR with a bioprosthetic valve in the United States adult population.

Aortic valve reconstruction surgery with Ozaki technique: initials results from a single center

Aortic valve (AV) replacement is the gold standard treatment for severe symptomatic AV disease. Recently, AV reconstruction surgery (Ozaki procedure) emerges as a surgical alternative with good results in the medium term. We retrospectively analyzed 37 patients who underwent AV reconstruction surgery between January 2018 and June 2020 in a national reference center in Lima, Peru. The median age was 62 years, interquartile range (IQR: 42-68). The main indication for surgery was AV stenosis (62.2%), in most cases due to bicuspid valve (19 patients, 51.4%). Twenty-two (59.4%) patients had another pathology with surgical indication associated to AV disease, 8 (21.6%) had dilatation of the ascending aorta with indication for replacement. One in-hospital death occurred (1/38, 2.7%) due to perioperative myocardial infarction. There was a significant reduction in the medians of the peak (70 mmHg, CI 95% = 50.03-79.86 vs. 14 mmHg, CI 95% = 11.93-17.5, p < 0.0001) and mean (45.5 mmHg CI 95% = 30.6-49.68 vs. 7 mmHg, CI 95% = 5.93-9.6, p < 0.0001) AV gradients when we compared baseline characteristics with first 30-days results. In an average of 19 (± 8.9) months of follow-up, survival, reoperation-free survival for valve dysfunction, and survival free of AV insufficiency ≥ II were 97.3%, 100% and 91.9%, respectively. Significant reduction in the medians of the peak and mean AV gradients was maintained. AV reconstruction surgery showed optimal results in term of mortality, reoperation-free survival, and hemodynamic characteristics of the neo-AV.

Three-year results of aortic valve neocuspidization (Ozaki procedure): a multiple-center retrospective study

Three-year results of aortic valve neocuspidization (Ozaki procedure): a multiple-center retrospective study

Aortic valve neocuspidization using the Ozaki Technique for bicuspid aortic valve: The first case at Central Military Hospital of Azerbaijan

Conventional aortic valve replacement (AVR) remains the standard treatment for aortic valve stenosis or insufficiency, but emerging techniques focus on valve reconstruction rather than replacement. One such method is the Ozaki procedure, which involves replacing each valve leaflet with glutaraldehyde-treated autologous pericardium to restore the natural anatomy of the aortic valve. Although challenging, especially for bicuspid aortic valves, this technique has shown success after a learning period. We report the case of a 54-year-old woman with a history of colorectal cancer, who underwent surgery for severe stenosis of a bicuspid aortic valve using tricuspidization with glutaraldehyde-treated autologous pericardium.

Midterm outcomes of the Ozaki procedure in patients with a bicuspid aortic valve: retrospective single-center, non-randomized, parallel-group study

BACKGROUND: An alternative to plastic surgery on the bicuspid aortic valve (BAV) can be replacement of the leaflets with autopericardium using the Ozaki technique. The procedure is characterized by excellent hemodynamic results in the short and long term in patients with tricuspid aortic valve (TAV). However, the question remains about the long-term results of the procedure and the frequency of reoperations in patients with BAV.&#x0D; OBJECTIVE: To analyze the midterm outcomes of the Ozaki procedure in patients with BAV.&#x0D; MATERIALS AND METHODS: Retrospective single-center, non-randomized, parallel-group study was conducted. Since January 2015 to October 1, 2023, the clinic performed 809 Ozaki procedures. The work included 540 patients with studied midterm and long-term outcomes for up to 5 years. Both isolated aortic valve replacement and combined operations with coronary artery bypass grafting and (or) correction of mitral and tricuspid valve defects were performed.&#x0D; RESULTS: Midterm mortality was 5.7% (n=3) in the group with BAV and 7.3% (n=36) in the group with TAV. Reoperation for aortic regurgitation was required in 16 patients (2.9%): 1 patient (1.9%) in BAV group and 15 (3.3%) in TAV group. Freedom from reoperations in patients with BAV after the Ozaki procedure for up to 5 years was 95.4%, in the group with TAV — 92.6%. The peak gradient on the aortic valve in the group with BAV was 16±7.3, in TAV group— 16.4±10.9. 5 years after surgery, the mean gradient on the aortic valve does not exceed 10 mm Hg.&#x0D; CONCLUSION: The Ozaki operation in patients with BAV is an effective and safe procedure in the midterm follow-up period.

Pediatric Aortic Valve Surgery: The OZAKI Procedure as a Surgical Option

Pediatric Aortic Valve Surgery: The OZAKI Procedure as a Surgical Option

Ozaki procedure—re-construction of aortic valve leaflets using autologous pericardial tissue: a review

Ozaki procedure—re-construction of aortic valve leaflets using autologous pericardial tissue: a review

Single center two years' experience of Ozaki procedure: Early follow-up.

The Ozaki Procedure is an innovative surgical technique aiming of aortic valve neocuspidization using glutaraldehyde-treated autologous pericardium was first developed by Ozaki et al in 2007. With this newly developed technique, valve replacement was achieved without using prosthetic material due to both aortic stenosis and aortic insufficiency. Between December 2020 and December 2022, a total of 59 patients were operated on with the Ozaki Procedure due to aortic valve pathologies in our center. We evaluated the pre- and postoperative as well as the first-month data of a total of 44 patients with isolated the Ozaki Procedure and compared their echocardiographic changes. Patients with isolated aortic valve pathology were included in the study. Fifteen patients who underwent simultaneous coronary artery bypass surgery and Ozaki Procedure were excluded from the analysis. In the first month after the operation, n:2 (%4.5) patients died. When the preoperative and postoperative 1st month echocardiographic data of the remaining patients were compared, it was found that the decrease in mean gradient, max gradient and peak velocity values in the aortic valve was statistically significant. This is due to the fact that reaching neo-valves has very similar hemodynamics to the native aortic valve. Aortic valve neocuspidization by Ozaki Procedure may be a viable alternative to both surgical aortic valve replacement (AVR) and transcatheter aortic valve implantation. Its popularity and application is increasing all over the world. Short and mid-term results are available in the literature. The short and mid-term results are good, and the long-term results are hopeful.

The Ozaki Procedure: Standardized Protocol Adoption of a Complex Innovative Procedure

BackgroundThe Ozaki procedure using autologous pericardium is an interesting but complex alternative for aortic valve replacement. We present a standardized approach to minimize the learning curve and confirm reproducibility. MethodsAfter careful preparation, from May 2015 to February 2021, an Ozaki procedure was performed on 46 patients age 51 ± 14 years. Seven had unicuspid (15%), 29 bicuspid (63%), and 10 tricuspid (22%) aortic valves, and 2 patients had endocarditis. Endpoints were operative learning curves, perioperative outcomes, intermediate-term valve hemodynamics, reintervention, health-related quality of life (MacNew Heart Disease Health-Related Quality of Life questionnaire), and mortality. ResultsCardiopulmonary bypass and aortic clamp times decreased from 145 to 125 ​minutes and 120 to 100 ​minutes, respectively, over the first 20 cases, reflecting the learning curve. There was no major perioperative morbidity or mortality. Median postoperative stay was 6.9 days. Aortic regurgitation was mild or less in all but 2 patients who developed moderate aortic regurgitation. Mean aortic valve gradient was 7.9 mmHg postoperatively, 9.2 mmHg by 6 months, and constant thereafter. Left ventricular ejection fraction was 58% preoperatively, 60% at 6 months, and remained stable thereafter. One patient developed infective endocarditis 7 months postoperatively, failed medical management, and underwent valve replacement at 14 months. Two-year survival was 96%, with 1 noncardiac death at 16 months. Health-related quality of life in mental, physical, and emotional domains was better than matched norms, global 6.2 vs. 5.0 (p < 0.0001). ConclusionsUsing a well-prepared standardized approach, the Ozaki procedure is reproducible with a short learning curve, excellent hemodynamic performance, and good quality of life.

Early aortic valve neocuspidization failure due to xenograft leaflet tear in a young adult.

Aortic valve neocuspidization, initially described by Ozaki and colleagues, has become an increasingly popular treatment approach for aortic valve disease in both adult and paediatric populations. We report a case of an 18-year-old man with severe aortic regurgitation who underwent the Ozaki procedure using photo-oxidized bovine pericardium. Around 5 weeks after the surgery, he developed early symptomatic valve failure due to multiple leaflet tears requiring urgent reoperation.

Aortic valve neocuspidization with the Ozaki procedure in congenital aortic valve disease: Early results

Background: In this study, we present our early results with the Ozaki procedure in the treatment of congenital aortic valve disease. Methods: Between July 2021 and July 2023, a total of 14 patients (10 males, 4 females; median age: 13.9 years; range, 8.5 to 15 years) who underwent neoaortic valve reconstruction of three leaflets using Ozaki procedure were retrospectively analyzed. Preoperative, postoperative, and follow-up echocardiogram images were evaluated. Results: Preoperative indications were aortic regurgitation (n=3) or combined aortic stenosis and regurgitation (n=11). The median aortic annular diameter was 23 (range, 19.5 to 25) mm on preoperative echocardiography. The median preoperative peak systolic aortic valve gradient for patients with aortic stenosis was 60 (range, 45 to 93) mmHg. The median preoperative aortic valve regurgitation grade was 4 (range, 3 to 4). Autologous pericardium and bovine pericardium were used in 12 and two patients, respectively. There was no conversion to valve replacement, myocardial infarction, or mortality in the early postoperative period. The median follow-up time was 8.5 (range, 6 to 19) months. One patient who performed the Ozaki procedure with bovine pericardium underwent valve replacement eight months later. Conclusion: The Ozaki procedure can be performed safely and effectively in congenital aortic valve stenosis and insufficiency with promising early results.

Effectiveness and Safety of the Ozaki Procedure for Aortic Valve Disease in Pediatric Patients: A Systematic Review and Meta-Analysis.

The surgical treatment options for pediatric aortic valve disease are limited and have debatable long-term durability. In the current situation, the Ross procedure is considered in children for aortic valve disease(s). It is a complex surgical procedure with the risk of neo-aortic dilatation, converting a single valve disease into double valve disease, and associated with future re-interventions. Conversely, the Ozaki procedure has shown promising results in adults. Thus, the present study aimed to provide comparative evidence on the effectiveness and safety of the Ozaki versus Ross procedure for pediatric patients by performing a meta-analytic comparison of reporting outcomes. A total of 15 relevant articles were downloaded and among them, seven articles (one prospective study, five retrospective studies, and one case series) were used in the analysis. Primary outcomes such as physiologicallaminar flowpattern and hemodynamic parameters, and secondary outcomes such as hospital stays, adverse effects, mortality, and numbers of re-intervention(s) were measured in the meta-analysis. There were no significant differences in the age of patients between children who underwent the Ozaki procedure and those who underwent the Ross procedure at the time of surgeries. The Ozaki procedure is a good solution to an aortic problem(s) similar to the Ross procedure. Unlike the Ross procedure, the Ozaki procedure has restored a physiological laminar flow pattern in the short-term follow-up without the bi-valvular disease. Mean hospital stays (p = 0.048), mean follow-up (p = 0.02), adverse effects (p= 0.02), death, and numbers of re-intervention(s) of children who underwent the Ozaki procedure were fewer than those who underwent the Ross procedure. The time required for re-intervention(s) is higher for children who underwent the Ozaki procedure than those who underwent the Ross procedure. None of the procedures, including the Ozaki procedure for aortic valve disease(s), has significant effects on hemodynamic parameters and the frequent death rate of children after surgeries. Based on our analysis, we may suggest the Ozaki procedure for aortic valve disease surgery in children.

Does ozaki procedure have a future as a new surgical approach for aortic valve replacement? a systematic review and meta-analysis.

In 2014, Ozaki et al. introduced the neo-cuspidation (Ozaki procedure), a new valve from the pericardium, to reduce or even prevent the risk of chronic autoimmune inflammation and subsequent rejection or valve degeneration. Thus, the authors aimed to assess the safety and efficacy of the Ozaki technique in treating aortic valve diseases. A comprehensive search was performed via PubMed, the Cochrane Library, Scopus, and the Web of Science up to 20 February 2022. Random-effects meta-analysis models were employed to estimate the pooled mean and SD or event to the total of the Ozaki procedure. Relevant records were retrieved and analyzed by OpenMeta analyst software. A total of 2863 patients from 21 studies were finally included in our analysis. Ac. Ozaki technique showed statistical significance in terms of mean cardiopulmonary bypass time of 148mins (95% CI 144-152.2, P<0.001), mean aortic cross-clamp time of 112.46mins (95% CI 105.116, 119.823, P<0.001), reoperation with a low risk of 0.011 (95% CI 0.005, 0.016, P=0.047), conversion to aortic valve replacement with a low risk of 0.004 (95% CI -0.001, 0.008, P=0.392), finally ICU stay (days) and hospital length of stay (days) with a mean of 2.061 days (95% CI 1.535, 2.587, P<0.001) and 8.159 days (95% CI 7.183-9.855, P<0.001), respectively. The Ozaki procedure provides a safe surgical technique with low mean cardiopulmonary bypass time and aortic cross-clamp time; moreover, a mean of 2-day-postoperative hospital stay was observed with the Ozaki procedure with a low risk of conversion to aortic valve replacement, reoperation, ICU and hospital stay, and death.