Reconstruction of aortic valve by autologous pericardium (Ozaki's procedure): Single center experience in Vietnam

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

Background

The 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.

Methods

After 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.

Results

Cardiopulmonary 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).

Conclusions

Using a well-prepared standardized approach, the Ozaki procedure is reproducible with a short learning curve, excellent hemodynamic performance, and good quality of life.

A Case of Severe Aortic Stenosis after Aortic Valve Neocuspidization Using Autologous Pericardium (Ozaki Procedure)

A 56-year-old man with a history of left nephrectomy for Wilms' tumor on chronic hemodialysis underwent aortic valve neocuspidization using autologous pericardium (Ozaki procedure) for aortic stenosis (AS) due to a bicuspid aortic valve 6 years ago. The AS gradually progressed and a decrease in the left ventricular ejection fraction was observed. Because of this, we decided to perform reoperative aortic valve replacement using a mechanical valve. Intraoperative findings showed severe calcification at the site where the autologous pericardium was sutured to the annulus. However, the degeneration of the valve leaflets themselves was mild. While excellent mid-term results have been reported for the Ozaki procedure, the long-term results are still unclear. In this case, the annulus was severely calcified, which reduced the mobility of the leaflet. We report the first case of AS progression requiring reoperation in the long-term period after the Ozaki procedure.

Aortic Valve Reconstruction With Autologous Pericardium Versus a Bioprosthesis: The Ozaki Procedure in Perspective

Background We assessed the Ozaki procedure, aortic valve reconstruction using autologous pericardium, with respect to its learning curve, hemodynamic performance, and durability compared with a stented bioprosthesis. Methods and Results From January 2007 to January 2016, 776 patients underwent an Ozaki procedure at Toho University Ohashi Medical Center. Learning curves, aortic regurgitation (AR), and peak gradient, assessed by serial echocardiograms, valve rereplacement, and survival were investigated. Valve performance and durability were compared with 627 1:1 propensity-matched patients receiving stented bovine pericardial valves implanted from 1982 to 2011 at Cleveland Clinic. Learning curves were observed for aortic clamp and cardiopulmonary bypass times, AR prevalence, and early mortality. Decreased aortic clamp time was observed over the first 300 cases. New surgeons performing parts of the procedure after case 400 resulted in a slight increase in aortic clamp and cardiopulmonary bypass times. Among matched patients, the Ozaki cohort had more AR than the PERIMOUNT cohort (severe AR at 1 and 6 years, 0.58% and 3.6% versus 0.45% and 1.0%, respectively; P[trend]=0.006), although with a steep learning curve. Peak gradient showed the opposite trend: 14 and 17 mm Hg for Ozaki and 24 and 28 mm Hg for PERIMOUNT at these times (P[trend]<0.001). Freedom from rereplacement was similar (P=0.491). Survival of the Ozaki cohort was 85% at 6 years. Conclusions Patients undergoing the Ozaki procedure had lower gradients but more recurrent AR than those receiving PERIMOUNT bioprostheses. Although recurrent AR is concerning, results confirm low risk and good midterm performance of the Ozaki procedure, supporting its continued use.

Aortic valve neocuspidization using the Ozaki technique: A meta-analysis of reconstructed patient-level data

BACKGROUND

Aortic valve neocuspidization using the Ozaki technique has shown promising results both in adults and children.

METHODS

A systematic search of the PubMed and Cochrane databases was performed up to November 13, 2021. Individual patient data were reconstructed and analyzed from the Kaplan-Meier curves of all eligible studies for time-to-event outcomes.

RESULTS

We included a total of 22 studies reporting on 1,891 patients that underwent Ozaki reconstruction. Mean age at the time of surgery was 43.2 ± 24.5 years (65 ± 12.3 years for adult patients and 12.3 ± 3.8 years for pediatric patients). The most common indication was aortic stenosis (46.4%, 95% CI 34.1-58.6). Mean cross-clamp and cardiopulmonary bypass duration were 106.8 ± 24.8 minutes and 135.2 ± 35.1 minutes, respectively. Permanent pacemaker was implanted in 0.7% (95% CI 0.4-1.2) of the patients. At discharge, mean effective orifice area was 2.1 ± 0.5 cm²/m². At latest follow-up, peak gradient was 15.7 ± 7.4 mm Hg and only 0.25% (95% CI 0-2.3) had moderate aortic insufficiency. In-hospital mortality was 0.7% (95% CI 0.1-1.7). Late mortality was 1.9% during a mean follow-up of 38.1 ± 23.8 months. One-year, 3-year, and 5-year freedom from reoperation rates were 98.0 %, 97.0 % and 96.5%, respectively. More than half of the reoperations were due to infective endocarditis (51.5%, 95% CI 18.3-84.0). In our cohort, the risk of endocarditis per patient per year was 0.5%.

CONCLUSIONS

The midterm outcomes of the Ozaki procedure are excellent in terms of hemodynamics, survival, and freedom from reoperation. Acquiring long-term follow-up will help solidify this technique in the cardiac surgery armamentarium.

Aortic valve neocuspidization: Frequently asked technical questions

Since the first description by Professor Ozaki in 2011, more than 5500 aortic valve neocuspidization procedures have been performed worldwide, with promising short- and mid-term outcomes. We here report the nuances required to master this highly reproducible, standardized technique for the treatment of aortic valve disease.

Standardized Aortic Valve Neocuspidization for Treatment of Aortic Valve Diseases

BACKGROUND

Aortic valve replacement is the traditional surgical treatment for aortic valve diseases, yet standardized aortic valve neocuspidization (AVNeo) is a promising alternative that is gaining popularity. The purpose of this article is to review the available published literature of AVNeo using glutaraldehyde-treated autologous pericardium, also known as the Ozaki procedure, including indications, outcomes, potential benefits, and modes of failure for the reconstructed valve.

METHODS

A comprehensive literature search was performed using keywords related to aortic valve repair, AVNeo, or Ozaki procedure. All articles describing performance of AVNeo were reviewed.

RESULTS

Reported early mortality after AVNeo varies from 0% to 5.88%. The largest cohort of patients in the literature includes 850 patients with an inhospital mortality rate of 1.88%. Cumulative incidence of aortic valve reoperation was 4.2% in the largest series. Reoperation was uncommon and mainly due to infective endocarditis or degeneration of the reconstructed valve (most commonly due to aortic valve regurgitation, rather than stenosis).

CONCLUSIONS

Aortic valve neocuspidization is a versatile and standardized alternative to aortic valve replacement with a biological prosthesis. Early to midterm outcomes from a number of centers are excellent and demonstrate the safety and durability of the procedure. Long-term outcomes and clinical trial data are necessary to determine which patients benefit the most from this procedure.

Aortic Valve Neocuspidization Using Autologous Pericardium (Ozaki Procedure): an Alternative to Aortic Valve Replacement in Adult Cardiac Surgery?

Purpose of the Review

The aim of this article is to describe the technique of aortic valve neocuspidization using autologous pericardium (AVNeo, “OZAKI procedure”) in adult cardiac surgery, to analyze recent findings, and to discuss benefits and limitations of this technique.

Recent Findings

Potential benefits of this technique include excellent hemodynamic performances, minimal use of foreign material, low rates of permanent pacemaker implantation, and omission of oral anticoagulation. However, data regarding the durability of the procedure are hitherto limited, and the procedure is associated with a higher complexity compared to aortic valve replacement.

Summary

AVNeo using autologous pericardium in adult cardiac surgery is a promising technique providing several benefits. However, there is a major unmet need for more data, especially regarding long-term durability. Thus, based on currently available data, we recommend careful patient selection within the heart team and shared decision-making with the informed patient.