Aortic valve reconstruction with autologous pericardium for dialysis patients

Precise reconstruction of the aortic valve using glutaraldehyde-treated autologous pericardium in new formula: a case report

BACKGROUND

The current study presents a novel and precise surgical technique for complete reconstruction of the aortic valve using glutaraldehyde-treated autologous pericardium in a patient with aortic valve disease and endocarditis. The technique aims to provide a more effective and reproducible method for aortic valve repair, with the goal of improving outcomes and quality of life for patients with aortic valve disease.

CASE PRESENTATION

A 35-year-old Iranian male with aortic valve disease and endocarditis underwent aortic valve reconstruction surgery. Preoperative echocardiography showed a degenerative aortic valve with severe regurgitation, reduced left ventricular ejection fraction, and specific aortic root dimensions. The surgical technique involved precise measurements and calculations to design the size and shape of the new aortic valve cusps using autologous pericardium, with the goal of optimizing coaptation and function. The surgeon calculated the intercommissural distance based on the aortic annulus diameter to determine cusp size and shape. He tailored the pericardial cusps to have a height equal to 80% of the coaptation margin length. Detailed suturing techniques were used to ensure proper alignment and coaptation of the new cusps. Intraoperative evaluation of the valve function using suction and transesophageal echocardiography showed good coaptation and minimal residual regurgitation. At the 3-year follow-up, the patient had a well-functioning aortic valve with only trivial leak and was in satisfactory clinical condition.

CONCLUSIONS

Glutaraldehyde-treated autologous pericardium is a validated leaflet alternative, and the causes of its failure are late annular dilatation and other technique breakdowns. Current evidence reveals that aortic valve reconstruction with glutaraldehyde-treated autologous pericardium is associated with many advantages with the potential to improve patient outcomes and quality of life. Further clinical studies are warranted to evaluate the long-term durability and efficacy of this approach.

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 stenosis in chronic kidney disease: challenges in diagnosis and treatment

Chronic kidney disease (CKD) is becoming increasingly common and is associated with development and rapid progression of aortic stenosis (AS). Patients with AS and CKD have higher mortality rates than those with AS of similar severity and normal kidney function. The diagnosis of severe AS in patients with CKD is often challenging due to alterations in haemodynamics and heart structure, and integration of data from multiple imaging modalities may be required. When indicated, the definitive treatment for severe AS is aortic valve replacement. Patients with CKD are candidates for bioprosthetic valve replacement (surgical or transcatheter aortic valve implantation) or mechanical valve replacement. However, for patients with CKD, lifetime management is complex, as patients with CKD have a higher competing risk of bioprosthetic structural valve deterioration, bleeding in the setting of systemic anticoagulation and mortality related to CKD itself. The involvement of a heart-kidney multidisciplinary team in the care of patients with CKD and severe AS is ideal to navigate the complexities of diagnosis and management decisions.

Modification of human pericardium by chemical crosslinking

Autologous and allogenic human pericardia used as biomaterials for cardiovascular surgery are traditionally crosslinked with glutaraldehyde. In this work, we have evaluated the resistivity to collagenase digestion and the cytotoxicity of human pericardium crosslinked with various concentrations of glutaraldehyde in comparison with pericardium crosslinked by genipin, nordihydroguaiaretic acid, tannic acid, and in comparison with unmodified pericardium. Crosslinking retained the wavy-like morphology of native pericardium visualized by second harmonic generation microscopy. The collagenase digestion products were analyzed using SDS-PAGE, capillary electrophoresis, and a hydroxyproline assay. Glutaraldehyde and genipin crosslinking protected the native pericardium efficiently against digestion with collagenase III. Only low protection was provided by the other crosslinking agents. The cytotoxicity of crosslinked pericardium was evaluated using xCELLigence by monitoring the viability of porcine valve interstitial cells cultured in eluates from crosslinked pericardium. The highest cell index, reflecting both the number and the shape of the monitored cells was observed in eluates from genipin. Crosslinking pericardium grafts with genipin therefore seems to be a promising alternative procedure to the traditional crosslinking with glutaraldehyde, because it provides similarly high protection against degradation with collagenase, without cytotoxic effects.