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Biomedical subjects

J H Oury

Publications and source records attributed to J H Oury.

At least 19 recordsLinked to original sources
PubMed1998

Evolving experience with cryopreserved mitral valve allografts.

Allograft valves have been used for aortic valve replacement (AVR) for 35 years with excellent results. Early attempts at mitral valve replacement (MVR) with mitral valve allograft were unsuccessful mainly due to technical issues of measurement of appropriate graft size, difficulty of reimplantation, and early dehiscence of the papillary muscle anastomosis. Recently, interest in this procedure has been rekindled by successful laboratory experiments with mitral valve allograft implantation and improved understanding of the mitral valve apparatus from extensive mitral valve repair experience. In this article, we discuss the rationale for allograft use, the historical perspective of allograft use, and technical problems, along with current solutions and clinical outcomes of MVR with mitral valve allograft. Tricuspid valve replacement (TVR) with allograft mitral valve also is briefly discussed.

Animals↗
PubMed1996

Clinical aspects of the Ross procedure: indications and contraindications.

In the past decade, the pulmonary autograft procedure has emerged as the operation of choice for young individuals with aortic root pathology not amenable to repair. This is due in large part to the durability of the pulmonary autograft in the aortic position. Freedom from thrombosis and long-term anticoagulation also provide support for its application, as well as the pulmonary autograft's similarity to the human aortic valve. The present indications for the Ross procedure continue to broaden. Patient age is certainly a factor, with the upper limit being 50 years. Patients who present with mechanical or bioprosthetic aortic valve dysfunction also seem to be appropriate candidates for the procedure, as do those who present with active endocarditis. Athletes also are an appropriate subset based on the absence of anticoagulation and the extreme physiological and hemodynamic consequences of their chosen field. Contraindications to the Ross procedure include multivessel coronary artery disease as well as multiple pathology in which a second valve replacement device is required. Extremes of age and severely depressed left ventricular function also contradict application of the pulmonary autograft.

Age Factors↗
PubMed1994

Ischemic mitral valve disease: classification and systemic approach to management.

One hundred sixty-nine consecutive patients with coronary artery disease and mitral valve pathology operated during the past 5 years were reviewed (98% follow-up). Eighty-seven patients underwent mitral valve repair and 82 mitral valve replacement with concomitant coronary artery bypass grafting (number of AV grafts = 3). An analysis of these patients (age range 48 to 92 [mean 69]) and a classification based on anatomic pathology of the mitral apparatus is presented. Flexible ring annuloplasty was utilized in all repairs and chordal-sparing techniques in all valve replacements. There was equal mortality for replacement and repair in this subset of high risk patients. Structural valve dysfunction of repaired valves was more common (5/81 [6.0]) than primary tissue valve failure after mitral valve replacement (0 patients).

Aged↗
PubMed1993

Management of systemic atrioventricular valve regurgitation in infants and children.

Since September 1979, 53 patients have required operation for systemic atrioventricular valve regurgitation at Children's Hospital and Health Center of San Diego. (Primary repairs of atrioventricular canal defects are excluded from this report.) Diagnoses include single ventricle, cardiomyopathy, congenital mitral insufficiency , Marfan's disease, rheumatic heart disease, and a history of prior repair of atrioventricular canal defect. Ages ranged from 4 months to 19 years; median age is 5 years. In 31 patients, the atrioventricular valve could be repaired. In 24 patients, the valve was replaced (including two patients previously repaired). There were four operative deaths, all in the valve replacement group: three following valve replacement, and one following emergency thrombectomy. Two early failures in the repair group required valve replacement. Techniques for repair included leaflet resection, commissural annuloplasty, ring annuloplasty, and chordal shortening. Follow-up reveals good-to-excellent status in 38 patients. There were seven late deaths: six following valve replacement (one death valve related). Current surgical technique permits repair of the systemic atrioventricular valve in many infants and children requiring operation for regurgitation. The long-term results of valve repair are good to excellent. Repair avoids the morbidity and mortality of valve replacement, e.g., anticoagulation, fixed orifice size, and catastrophic mechanical valve malfunction.

Actuarial Analysis↗
PubMed1989

Late reoperation for systemic atrioventricular valve regurgitation after repair of congenital heart defects.

Since 1979, 17 infants and children have undergone reoperation for systemic atrioventricular (AV) valve regurgitation 6 weeks to 7 years after repair of congenital heart defects. Prior operations were repair of incomplete or complete AV canal (14 patients), Mustard repair of complex transposition of the great arteries including ventricular septal defect closure (2 patients), or first-stage operation for hypoplastic left heart (1 patient). Age ranged from 6 months to 11 years. In 12 of the 17 patients (10, AV canal; 1, transposition; 1, hypoplastic left heart), valve reconstruction was possible. Operative techniques included a combination of septal cleft approximation, leaflet resection, commissural annuloplasty, or ring annuloplasty. There were no operative deaths, and there were no reoperations in the repair group. The condition of these patients has improved. Follow-up ranges from 1 month to 9 years (mean follow-up, 4.1 years). Five of the 17 patients (4, AV canal; 1, transposition) underwent valve replacement. There were no operative deaths. Follow-up ranges from 3 to 8 years. Three patients later underwent re-replacement of the prosthetic valve; there was 1 late death. The condition of all 4 survivors is improved. Substantial AV valve regurgitation can occur months or years after repair of congenital heart defects. A combination of reconstructive techniques may be useful in preserving native valve function and avoiding systemic AV valve replacement.

Child↗
PubMed1989

Twenty-year comparison of the human allograft and porcine xenograft.

This study compares a retrospective consecutive series of human allografts and concurrent porcine xenografts implanted over a 10-year interval. There were 571 allograft valves and 1,351 xenograft valves implanted in the aortic and mitral position with mean follow-up of 12.8 years for the allografts and 6.2 years for the xenografts. This study compares the incidence of structural deterioration over long-term follow-up. We found that there was no significant difference between four manufacturers of porcine xenografts, in spite of substantial differences in processing techniques. We found that there was a significant difference in allografts that were premounted on stents as compared with allografts that were not premounted on stents for aortic valve replacement. We found that there was no significant difference between allografts for aortic valve replacement that were not premounted on stents and porcine xenografts implanted in the aortic position. These findings are in marked contrast to those of other reported series with the use of allograft valves.

Animals↗
PubMed1989

Durability of the viable aortic allograft.

Of 581 aortic allografts implanted since 1967, 421 were analyzed for structural deterioration. This series is unique in that it includes patients from the early allograft experience. All allografts were cleanly procured, antibiotic sterilized, and either stored at 4 degrees C for up to 8 weeks or frozen to liquid nitrogen temperatures with cryopreservation to preserve the viable cusp fibroblasts. There were 25 frozen mounted aortic valves with a median time to valve failure of 12.1 years, which was not significantly different from the 12.5-year period for 114 fresh free-sewn aortic valves. The median time to valve failure was 6.6 years for 90 fresh-mounted aortic valves and 8.6 years for 192 fresh-mounted mitral valves (p = 0.05). The difference between all mounted and unmounted grafts was significant (p = 0.0001). In all groups, viable fibroblasts were present in specimens explanted up to 5 years after the operation. All specimens returned after more than 10 years were almost totally acellular. Evidence of increased collagen, suggesting that the fibroblasts survive implantation and then gradually die, was present in all specimens. This series suggests that durability of the unmounted viable allograft for aortic valve replacement is greater than for other types of tissue valves. Pre-mounted allografts for aortic or mitral valve replacement have a median survival of 8 years and are not more durable than other tissue valves.

Aortic Valve↗
PubMed1988

Long-term fate of valve cusp patches for right ventricular outflow tract reconstruction.

Six patients with tetralogy of Fallot, pulmonary atresia, or absent pulmonary valve syndrome were operated with a RVOT patch containing a single aortic allograft cusp from an adult donor. The method was based on animal work with similar patches implanted in growing puppies and proved that the single cusp functioned as an effective RV outflow valve for several weeks after surgery. Postoperative angiograms in the animals confirmed nearly completely competent valves. Sacrifice of animals at 3 months documented that the allograft tissue was flexible without early deterioration or calcification. Clinical application of this method raised several questions regarding the procedure, its efficacy, and subsequent fate of the allograft valve in children requiring RVOT reconstruction. There were six children age 19 months to 10 years who required division of the pulmonary valve annulus to relieve pulmonary outflow obstruction or with absent pulmonary valve syndrome and compromised airways from pulmonary insufficiency. One patient had a positive culture from the valve and required immediate removal of the infected allograft. Patients had clinically competent pulmonary valves immediately after surgery with decreased right ventricular systolic and end-diastolic pressures when compared with patients in whom nonvalve patches were inserted. All patients had some degree of pulmonary insufficiency, but no symptoms. Follow-up up of five patients available 4 to 6 years after surgery revealed no patients with stenosis of the valve cusps, although two patients have severe, one moderate, and two mild pulmonary insufficiency. We conclude that a patch containing a single adult allograft valve cusp should be considered for all patients requiring reconstruction of the RVOT, particularly if RV overload is expected to compromise the immediate postoperative result.

Animals↗
PubMed1988

Comparison of Hancock I and Hancock II bioprostheses.

The Hancock II bioprosthesis was developed in order to provide the advantageous low pressure fixation, improved delrin stent design, and anticalcification treatment. These changes were made 6 years ago after 10 years of experience with the high pressure fixed rigid implantation ring and polypropylene stent used in the Hancock I valve. In 1983, based on our own experience with low pressure fixed valves in 76 patients, we began early clinical trials with the Hancock II valve. All valves were studied postoperatively by intraoperative catheterization and followed up with postoperative echocardiograms for measurement of valve gradients and areas. This series of 104 patients with Hancock II valves was then compared retrospectively with 119 patients receiving Hancock I valves from 1975 to 1983. A comparison of mortality, thromboembolism, and hemorrhage rates was not significantly different between groups and the valve failure incidence of Hancock I valves was an anticipated 2.34% per patient-year. There has been one primary tissue failure in the Hancock II series. This patient had fibrinous excrescences on the outflow surface of the valve in the aortic position. These nodules were compatible with an old thrombotic process of ill-defined nature. Further investigation resulted in reports of this phenomenon, which had resulted in early valve stenosis, from other centers implanting the Hancock II valve. In conclusion, the Hancock II bioprosthesis has theoretical advantages over the Hancock I in stent design, fixation pressure, and anticalcification potential. There is an unusual thrombotic process in aortic valve replacements that we have not observed in the Hancock I group or in our experience with other porcine xenografts.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1987

A comparison of replacement and reconstruction in patients with mitral regurgitation.

The factors that make mitral reconstruction an attractive alternative to valve replacement are increased anatomical valve orifice, preservation of the valvular apparatus, improved longevity over porcine xenografts, and no requirement for long-term anticoagulation. In our experience the majority of patients with mitral regurgitation have degenerative valve disease. This comparative series of patients operated on over a 10 year interval includes 72 with replacement and 112 with reconstruction. The average cross-clamp times were 69 minutes for reconstruction and 44 minutes for replacement. The hospital mortalities were 3.6% and 18.1%, respectively. Postoperative valve areas as determined by Doppler echocardiography were 2.69 cm2 for replacement and 2.67 cm2 for reconstruction (p = 0.9). The valve failure rate was 2.0% per patient-year for reconstruction and there were no failures in the replacement group. The reoperation incidence for reconstruction was 20% at 10 years. The remaining patients, although clinically well, had varying degrees of stable, nonprogressive mitral regurgitation. Forty-five percent had mild to trivial regurgitation detectable by echocardiographic studies. The decision between mitral valve reconstruction and mitral valve replacement remains a highly controversial issue. The failure of our data to demonstrate superior valve function for patients with mitral regurgitation undergoing valve reconstruction suggests a need for careful analysis of reconstruction with respect to effective valve orifice and incidence of regurgitation.

Bioprosthesis↗
PubMed1987

Long-term follow-up of viable frozen aortic homografts. A viable homograft valve bank.

There is currently a renewed interest in the use of both fresh and commercially available frozen homograft valves for children and young adults. This has prompted us to review a series of 32 patients who received frozen homograft valves for aortic replacement between 1973 and 1975. The cryogenic technique evolved to include the use of selected antibiotics and equilibrated dimethyl sulfoxide solution to freeze homografts at a rate of 1 degrees C per minute to liquid nitrogen temperatures of -196 degrees C. Histologic sections of experimental frozen valves explanted 6 months postoperatively revealed the presence of viable donor cells, and tissue culture demonstrated the reproductive capacity of cusp fibroblasts. Of the 32 frozen viable homografts implanted in this series, 23 were inserted as free-sewn aortic replacements and nine were premounted on stents before implantation in the aortic position. There were two operative deaths, and three valves failed as a result of the technical problems of mounting in one patient and surgical insertion of a free graft in two patients. Of the 22 patients who remained at long-term risk, 13% with free-sewn grafts and 57% with premounted valves underwent reoperation for valve failure. After 10 years of follow-up, 15 (68%) of these patients, 12 (80%) with free-sewn and three (43%) with premounted valves, are alive with their original valve in place. Actuarial analysis shows that 58% of the 32 valves implanted are functional at the beginning of the eleventh year. There have been six late deaths resulting in an overall actuarial patient survival rate of 79% at 10 years and 69% after 13 years. These clinical results are believed to add support to our current application of the frozen homograft in selected patients.

Adult↗