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

The Ozaki procedure has emerged as a valuable option for treating various aortic valve pathologies. This review article delves into the intricacies of this innovative surgical approach by exploring its adaptation to the complex anatomy and physiology of the aortic root. The diverse etiologies of aortic valve diseases, ranging from congenital anomalies to degenerative changes, make treatment selection a complex challenge. Aortic valve replacement has traditionally been the gold standard, but emerging evidence supports valve repair techniques, emphasizing the importance of preserving native tissue. Nevertheless, issues like lifelong anticoagulation with mechanical valves and patient-prosthetic mismatch remain. The Ozaki procedure offers a compelling alternative by utilizing autologous pericardium or a tissue substitute to construct new aortic valve leaflets. This technique, standardized by Dr. Ozaki in 2007, provides a customizable and adaptable solution. The article highlights the anatomy of the aortic root, emphasizing the critical role of the sinus of Valsalva and interleaflet triangles in maintaining proper valve function. The procedure's unique adaptation to aortic root dynamics allows for reduced mechanical stress during systole and diastole, mimicking the natural valve's behavior. Furthermore, Ozaki leaflets exhibit promising hemodynamics and reduced risks of complications, such as permanent pacemaker implantation and patient-prosthetic mismatch. The use of autologous pericardium in the Ozaki procedure presents advantages, including enhanced tissue strength, minimal immunogenicity, and reduced risk of immune-mediated calcification. These factors contribute to the longevity and resilience of the reconstructed valve. This comprehensive review aims to shed light on the procedure's intricacies, its alignment with aortic root anatomy and physiology, and its potential as a valuable tool in the armamentarium of aortic surgeons.

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.

Mechanical characterization of an in-body tissue-engineered autologous collagenous sheet for application as an aortic valve reconstruction material.

The reconstruction of the aortic valve using glutaraldehyde-treated autologous pericardium is known as "aortic valve neo-cuspidization" (AVNeo). In-body tissue architecture (iBTA), a cell-free, in vivo tissue-engineering technology that can form autologous implantable tissues of the desired shape by subcutaneous embedding specially designed molds, was used to prepare sheet-like collagenous tissues called "Biosheets". Cylindrical molds with several line slits arranged in an alternating (n = 30) or parallel (n = 36) pattern were subcutaneously embedded in goats (n = 12) for 2 or 3 months. The tubular tissues formed in the molds were dried and then cut in the longitudinal direction, thus obtaining Biosheets (5 × 7 cm). The success rate was 97.6% when using the alternating-pattern molds and 97.2% for the parallel molds. Thickness mapping of the Biosheets showed that their entire surface, except for the line-projection portions, was smooth without any defects. The average wall thickness could be controlled over a range of ca. 0.2-0.5 mm by changing the size of the gap (0.75-1.5 mm) in the molds. The alternating slit-patterned Biosheets were found to be almost isotropic in their mechanical properties (ultimate tensile strength, fracture strain, and Young's modulus). Although the composition of the Biosheet wall was heterogeneous in terms of its density (which varied with the thickness), the breaking strength of all the alternating-patterned Biosheets increased almost linearly with the thickness within the range of the thickness of clinically used glutaraldehyde-treated pericardium as a control, and was larger than that of human aortic valve leaflets. Therefore, the alternating-patterned Biosheets have potential for use in an alternative aortic leaflet material in AVNeo.

Midterm outcomes after aortic valve neocuspidization with glutaraldehyde-treated autologous pericardium.

OBJECTIVE: We had previously reported the short-term results of the aortic valve neocuspidization (AVNeo) procedure. We have now evaluated the midterm results with the longest follow-up of 118 months. METHODS: From April 2007 through December 2015, 850 patients were treated with AVNeo using autologous pericardium. Medical records of these patients were retrospectively reviewed. The procedure was on the basis of independent tricuspid replacement using autologous pericardium. The distances between the commissures were measured with an original sizing device, the pericardial cusp was trimmed using an original template, and then sutured to the annulus. RESULTS: There were 534 patients with aortic stenosis, 254 with aortic regurgitation, 61 with aortic stenoregurgitation, 19 with infective endocarditis, and 5 with a previous aortic valve procedure. Besides 596 patients with tricuspid aortic valve, 224 patients had bicuspid valve, 28 had unicuspid valve, and 2 had quadricuspid valve. There were 444 male and 406 female patients. The median age was 71 (range, 13-90) years old. Preoperative echocardiography revealed a peak pressure gradient average of 68.9 ± 36.3 mm Hg with aortic stenosis. Surgical annular diameter was 20.9 ± 3.3 mm. There was no conversion to a prosthetic valve replacement. There were 16 in-hospital mortalities. Postoperative echocardiography revealed a peak pressure gradient average of 19.5 ± 10.3 mm Hg 1 week after surgery and 15.2 ± 6.3 mm Hg 8 years after surgery. Fifteen patients needed reoperation (13 infective endocarditis, 1 break of thread, and 1 tear of cusp case). The mean follow-up period was 53.7 ± 28.2 months. Actuarial freedom from death, cumulative incidence of reoperation, and that of recurrent moderate aortic regurgitation or greater was 85.9%, 4.2%, and 7.3%, respectively, with the longest follow-up of 118 months. CONCLUSIONS: The midterm outcomes of AVNeo using autologous pericardium were satisfactory in 850 patients with various aortic valve diseases. However, further randomized, multicenter prospective studies are needed to confirm the results of the current study.

Trileaflet aortic valve reconstruction with a decellularized pericardial patch in a sheep model.

BACKGROUND: The purpose of this study was to provide a preliminary assessment of the performance of a decellularized pericardial patch in a trileaflet aortic valve reconstruction in a long-term juvenile sheep model. METHODS: A sheep surgical model was used to perform a complete trileaflet reconstruction (Ozaki technique) of the aortic valve with 3 separate pericardial patches. Valve function was assessed 1 week, 3 months, and 6 months after surgery via transthoracic echocardiography. Calcification resistance and host cell infiltration of the pericardial material were assessed at 6 months after surgery. RESULTS: Three of 6 sheep with implanted pericardial neo-cusps survived until the planned time of sacrifice after surgery, whereas 3 animals had a successful implant but died shortly after the procedure as the result of a bad recovery from cardiopulmonary bypass. Echocardiography at 6 months revealed a high coaptation area with only minimal regurgitation. In all explanted leaflets, cusp tissue was soft. There was only minimal calcification in 8 of 9 leaflets. CONCLUSIONS: Aortic valves reconstructed with a decellularized pericardial patch demonstrated adequate diastolic function with minimal regurgitation and resistance to calcification. Combining the Ozaki technique with this decellularized pericardial scaffold showed adequate hemodynamics, sustained mechanical integrity of the patch and limited calcification of the material. These results, together with earlier experimental and clinical data, indicate the potential of this material for aortic valve repair.

A Case of Severe Unicuspid Aortic Valve Stenosis: Valve Repair With Tricuspidization in an Adult.

A 33-year-old male was referred to our institute with acute heart failure. The patient was found to have a unicuspid aortic valve (UAV) and severe aortic stenosis. He had been followed at a local university hospital during childhood. However, he stopped visiting the outpatient clinic after becoming an adult. His condition subsequently worsened, and he ultimately presented to our hospital with cardiogenic shock. In Japan, some adult congenital heart disease (ACHD) patients continue to be followed by pediatric cardiologists, though the patterns of practice are variable. This report describes the case of a patient who became lost to follow-up in early adulthood. We thus focus on this ACHD case as an example of the effects of inadequate communication among doctors and the need to establish better ACHD management protocols for treating this patient population.

Aortic Valve Reconstruction Using Autologous Pericardium for Aortic Stenosis.

BACKGROUND: To determine the feasibility of original aortic valve reconstruction (AVRec) for patients with aortic stenosis (AS), 416 consecutive cases were reviewed. METHODS AND RESULTS: AVRecs for AS were performed for 416 patients from April 2007 through April 2013. All 416 patients were retrospectively reviewed. One hundred and fourteen patients had bicuspid valves and 16 had unicuspid valves. There were 182 men and 234 women. Mean age was 71.2±12.0 years old. On preoperative echocardiography, peak pressure gradient averaged 79.0±33.6 mmHg. Surgical annular diameter was 20.1±2.8 mm. The procedure is based on independent tricuspid replacement by autologous pericardium using original sizing apparatus and template. There was no conversion to prosthetic valve replacement. There were 8 in-hospital mortalities due to non-cardiac cause. On postoperative echocardiography, peak pressure gradient averaged 21.2±10.7 mmHg 1 week after surgery and 14.3±5.0 mmHg 5.5 years after surgery. Four reoperations were done for infective endocarditis. The other 412 patients had less than mild regurgitation. No thrombo-embolic events were recorded. The mean follow-up period was 25.2±17.5 months. Freedom from reoperation was 96.7% with 73-month follow-up. CONCLUSIONS: Medium-term results were excellent. Original AVRec was feasible for the patients with AS. Long-term data will be presented in the future.

Aortic valve reconstruction using autologous pericardium for patients aged less than 60 years.

OBJECTIVE: We have performed an original aortic valve reconstruction using autologous pericardium. The feasibility for patients aged less than 60 years is reviewed. METHODS: From April 2007 to April 2013, aortic valve reconstruction was performed in 108 patients aged less than 60 years. A total of 51 patients had aortic stenosis, 7 patients had annuloaortic ectasia, 7 patients had infective endocarditis, and 43 patients had aortic regurgitation. Fifty-seven patients had bicuspid valves, and 11 patients had unicuspid valves. There were 75 male and 33 female patients, with a mean age of 47.8 ± 11.2 years. Preoperative echocardiography showed an average peak pressure gradient of 86.1 ± 35.1 mm Hg with aortic stenosis. The surgical procedure is based on the independent tricuspid replacement using autologous pericardium. First, the distance between the commissures is measured using an original sizing apparatus, and then the pericardial cusp is trimmed using an original template and sutured to the annulus. RESULTS: There was no conversion to prosthetic valve replacement. There were no in-hospital mortalities. Postoperative echocardiography showed an average peak pressure gradient of 14.8 ± 7.8 mm Hg 1 week after surgery and 12.8 ± 3.1 mm Hg 4 years after surgery. One patient required reoperation because of infective endocarditis. The other 107 patients showed less than mild aortic regurgitation. No thromboembolic events were recorded. The mean follow-up period was 34.2 ± 15.7 months. Freedom from reoperation was 98.9% with 76 months of follow-up. CONCLUSIONS: Original aortic valve reconstruction was feasible for patients aged less than 60 years. Long-term data will be disclosed in the future.

Reconstruction of bicuspid aortic valve with autologous pericardium--usefulness of tricuspidization.

BACKGROUND: This study describes the surgical treatment of bicuspid aortic valve with original aortic valve reconstruction. METHODS AND RESULTS: Aortic valve reconstruction was done in 102 patients with bicuspid aortic valve from April 2007 through September 2011. Thirty-four patients with ascending aortic diameter >45 mm underwent hemi-arch aortic replacement concomitantly. Seventy-seven patients had aortic stenosis, and 25 had aortic regurgitation (AR). Mean age was 63.7±10.0 years old. There were 55 men and 47 women. Harvested pericardium is treated with 0.6% glutaraldehyde solution. The distance between commissures is measured with an original sizing instrument. For bicuspid valve with raphe, the raphe is considered as a commissure in order to measure the distance between each commissure. Without a raphe, we create a new annular margin and commissure using coronary ostium and the sizing instrument as a guide. Then, pericardium is trimmed with original template. Three cusps are sutured independently. The preoperative averaged peak pressure gradient of 71.1±39.0 mmHg was decreased to 16.2±8.8, 13.3±6.0, and 13.9±5.6 mmHg, respectively 1 week, 1 year, and 3 years after operation. AR was trivial. One reoperation was recorded. Mean follow-up was 733 days. There were 5 late mortalities. No thromboembolic event was recorded. CONCLUSIONS: Medium-term results were excellent. Tricuspidization gave good opening and closure of aortic valve with excellent hemodynamics.

Aortic valve reconstruction using autologous pericardium for ages over 80 years.

BACKGROUND: We performed original aortic valve reconstruction using autologous pericardium; the feasibility for elderly patients is reviewed. METHODS: From April 2007 through September 2011, aortic valve reconstruction was carried out in 86 patients over the age of 80 years. Twenty-seven patients were male and 59 were female. Mean age was 82.9 ± 2.5 years. Seventy-two patients had aortic stenosis and 14 had aortic regurgitation. Mean preoperative surgical annular diameter was 19.5 ± 2.5 mm. There were 80 (90.7%) cases of small aortic annulus. Mean preoperative logistic EuroSCORE was 22.9 ± 15.8. RESULTS: Isolated aortic valve reconstructions were performed in 51 patients. Concomitant procedures included coronary artery bypass grafting in 6, hemiarch aortic replacements in 6, 9 maze procedures, and some combinations. No conversion to valve replacement was required. Mean follow-up was 1243 days. There were 3 hospital deaths due to noncardiac causes. No reoperation was needed. Survival at 56 months was 87.0%. No thromboembolic event occurred. Echocardiography 3.5 years after surgery revealed an average peak pressure gradient of 14.6 ± 3.8 mm Hg. No moderate or severe regurgitation was recorded. CONCLUSIONS: Aortic valve reconstruction is feasible for patients older than 80 years, resulting in good hemodynamics and a better quality of life, without anticoagulation.

A total of 404 cases of aortic valve reconstruction with glutaraldehyde-treated autologous pericardium.

OBJECTIVE: To determine the feasibility of original aortic valve reconstruction, 404 consecutive cases were reviewed. The early results are reported here. METHODS: Aortic valve reconstruction was performed for 404 patients from April 2007 through September 2011. The results for all 404 patients were reviewed retrospectively. There were 289 patients with aortic stenosis and 115 patients with aortic regurgitation. One hundred two patients had bicuspid aortic valves, 13 patients had unicuspid valves, and 2 patients had quadricuspid valves. There were 201 males and 203 females. Mean age was 69.0 ± 12.9 years. Preoperative echocardiography revealed an average peak pressure gradient of 79.6 ± 32.5 mm Hg with aortic stenosis. Surgical annular diameter was 20.3 ± 3.2 mm. The surgical procedure is based on the independent tricuspid replacement by autologous pericardium. First, the distance between the commissure is measured with an original sizing apparatus, then the pericardial cusp is trimmed using an original template, and it is sutured to the annulus. RESULTS: There were no conversions to prosthetic valve replacement. There were 7 in-hospital mortalities resulting from a noncardiac cause. Postoperative echocardiography revealed an average peak pressure gradient of 19.8 ± 10.2 mm Hg 1 week after surgery and 13.8 ± 3.7 mm Hg 3.5 years after surgery. Two patients needed reoperation because of infective endocarditis. The other 402 patients showed less than mild aortic regurgitation. No thromboembolic events were recorded. The mean follow-up period was 23.7 ± 13.1 months. Freedom from reoperation was 96.2% at 53 months of follow-up. CONCLUSIONS: Original aortic valve reconstruction was feasible in patients with various aortic valve diseases. Long-term data will be disclosed in the future.

Aortic valve reconstruction with autologous pericardium for dialysis patients.

OBJECTIVES: This study aimed to report on original aortic valve reconstruction for patients on dialysis. METHODS: Aortic valve reconstruction has been performed on 404 cases from April 2007 through September 2011. Among them, 54 cases on haemodialysis were retrospectively studied. Forty-seven patients had aortic stenosis, 5 had aortic regurgitation (AR), and 2 had infective endocarditis. Mean age was 70.2 ± 8.5 years. There were 35 males and 19 females. There were 27 primary aortic valve reconstructions, 11 with CABG, 6 with ascending aortic replacement, 5 with mitral valve repair and 4 with maze. First, in the procedure, harvested pericardium was treated with 0.6% glutaraldehyde solution. After resecting the cusps, we measured the distance between commissures with original sizing instrument. Then, the pericardium was trimmed with the original template. Three cusps were sutured to each annulus. RESULTS: Peak pressure gradient averaged to 66.0 ± 28.2 mmHg preoperatively, and decreased to 23.4 ± 10.7, 13.8 ± 5.5 and 13.3 ± 2.3 mmHg, 1 week, 1 year, and 3 years after the operation, respectively. No calcification was detected with echocardiographic follow-up. Recurrence of AR was not recorded with the mean follow-up of 847 days except for 1 case reoperated on for infective endocarditis 2.5 years after the operation. Three hospital deaths were recorded due to non-cardiac causes. Other patients were in good condition. There was no thromboembolic event. CONCLUSIONS: Medium-term results are excellent. Since warfarin for dialysis patients becomes problematic, a postoperative warfarin-free status is desirable. Aortic valve reconstruction can provide patients with a better quality of life without warfarin.

Aortic valve reconstruction of unicuspid aortic valve by tricuspidization using autologous pericardium.

BACKGROUND: Unicuspid aortic valve is a rare anatomic variant, but patients may require intervention for severe valve dysfunction at a young age. We introduce a new reconstructive technique for diseased unicuspid valve by tricuspidization with glutaraldehyde-treated autologous pericardium. METHODS: From April 2007 through January 2011, we performed 304 cases of aortic valve reconstruction using glutaraldehyde-treated autologous pericardium. During the same period, we encountered 9 patients with unicuspid aortic valve, including 8 male patients and 1 female patient. Mean age was 48.9±19.9 years (14-78 years). Two patients had aortic stenosis (AS), 1 had aortic regurgitation (AR), and 6 patients had both. Our original aortic valve reconstruction technique is characterized by the independent replacement of 3 leaflets with separate measurement of length between each commissure. In the case of a unicuspid aortic valve, we create a new commissure at a higher point along the raphe at the same level with the 1 normally existing commissure. RESULTS: No early mortality or major morbidity was recorded. Postoperative echocardiography showed trivial or no AR, with the peak pressure gradients averaging 10.6±3.3 mm Hg. One-year follow-up echocardiography revealed that the peak pressure gradients averaged 8.6±3.7 mm Hg, with trivial or no AR. The mean follow-up period was 551.1±51.4 days. All 9 patients are in good condition. No reoperation or any additional intervention has been necessary. CONCLUSIONS: Diseased unicuspid aortic valves were treated by our original aortic valve reconstruction technique with excellent early results. We continue to study the long-term results.

Tensile strength of human pericardium treated with glutaraldehyde.

PURPOSE: We have reconstructed aortic valves using autologous pericardium treated with glutaraldehyde since April 2007. However, the strength of the human pericardium has not been confirmed. We compared tensile strength between glutaraldehyde-treated human pericardium and aortic valve leaflets with various degrees of calcification to determine their suitability for use in aortic valve reconstruction. METHODS: We measured the ultimate tensile strength and elasticity of samples of glutaraldehyde-treated pericardia (n = 8), non-calcified (n = 12), calcified (n = 9) and decalcified (n = 21) aortic leaflets collected from 23 patients who underwent aortic valve surgery. Aortic valves were decalcified using a cavitational ultrasonic surgical aspirator. The pericardium was immersed in 0.6% buffered glutaraldehyde for 10 minutes and then rinsed three times for 6 minutes each in normal saline. RESULTS: The ultimate tensile strength of the glutaraldehyde-treated human pericardium, non-calcified, calcified and decalcified leaflets was 10, 2.8, 1.0 and 0.8 MPa, respectively. CONCLUSIONS: The ultimate tensile strength of glutaraldehyde-treated human pericardium was 4 times higher than non-calcified leaflets, indicating its suitability for application to aortic valve reconstruction. Calcified leaflets were slightly stronger than decalcified leaflets. Thus, calcification can be removed without altering the tensile strength of valve materials.

Angioplasty with autologous pericardium for bilateral coronary ostial stenosis in Takayasu disease.

Coronary ostial stenosis is usually treated by conventional coronary artery bypass graft surgery. Although patch angioplasty is a widely accepted alternative surgical treatment, it has been reported sporadically. We encountered bilateral ostial stenosis with Takayasu disease. This report describes successful patch angioplasty using glutaraldehyde-treated autologous pericardium of bilateral coronary ostial stenosis owing to Takayasu disease.