The homograft. A new dimension for cardiac valve replacement.
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Aortic Valve↗
Biomedical subjects
L Gonzalez-Lavin
Publications and source records attributed to L Gonzalez-Lavin.
Pulmonary homograft implantation for ventricular outflow tract reconstruction: early phase results.
The pulmonary valve homograft (PH) has been reported to have potential advantages over the aortic valve homograft, including a larger diameter, a thinner wall, and decreased intrinsic calcification. From January 16, 1986, to July 14, 1987, eight consecutive patients underwent repair of congenital cardiac anomalies using a cryopreserved PH. Patients ranged in age from 18 months to 32 years. Diagnoses included tetralogy of Fallot with pulmonary atresia (3 patients); tetralogy with absent pulmonary valve (1 patient); corrected transposition with pulmonic stenosis (1 patient); transposition of the great arteries, ventricular septal defect, and pulmonic stenosis (2 patients); and double-outlet right ventricle with pulmonic stenosis (1 patient). The PH was implanted orthotopically in the patient with absent pulmonary valve, and in the other 7 it was placed as a valved extracardiac conduit. Two of the tetralogy patients with severe bifurcational pulmonary stenosis and another with nonconfluent pulmonary arteries and origin of the left pulmonary artery from a patent ductus arteriosus had their repairs facilitated using the branching pulmonary arterial portion of the PH. There were no hospital or posthospital deaths. Postrepair right ventricular to left ventricular systolic pressure ratios were a mean of 0.35 at 18 hours postoperatively (range, 0.21-0.61). All patients were studied with Doppler and echocardiography after repair. The mean gradient across the PH was 9 mm Hg (range, 2-27 mm Hg), and no pulmonary valve incompetence was present. One patient (12.5%) required reoperation seven months after repair for conduit revision due to compression by the sternum and is now well.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Technique for repair of left ventricular free wall rupture.
A case of postinfarction left ventricular free wall rupture is reported. The technique used to repair the rupture is described, along with a modification of the technique.
Aged↗
Pacemaker system failure and other events in children with surgically induced heart block.
Of 1,193 consecutive pediatric (less than 18 years) patients undergoing intracardiac repair from 1975 to 1984, 38 (3.2%) developed surgically induced complete heart block and were treated by permanent pacemaker implantation. Anomalies included complete atrioventricular septal defect = 9 (24%), simple ventricular septal defect = 9 (24%), atrioventricular discordant connection = 8 (212), tetralogy of Fallot = 7 (182), and other complex anomalies = 5 (13%). There were no hospital deaths. follow-up was 100% complete. There were six late deaths = 16%. Actuarial survival was 79 + 9% at 10 years. None of the late deaths were related to disturbance of cardiac rhythm or pacemaker system failure. Twelve patients (32%), required 27 reoperations for various types of pacemaker system failure. Indications for reoperation included: lead failure (44%). Pulse generator failure (44%), and wound sepsis (12%). Actuarial freedom from any pacemaker related reoperation was 50 + 16% at 48 months and 25 + 15% at 96 months. Only first reoperation was found to be an incremental risk factor for subsequent reoperation (p = 0.03). Surgical heart block has been neutralized as a risk factor for hospital death after repair of congenital cardiac defects. The risk of the development of surgical heart block now approaches zero, as indicated by a decreased incidence (1 of 401 = 0.25%) in our institution from 1985 to 1987, as compared to the era 1975 to 1984 (p = 0.001).
Actuarial Analysis↗
The Ross operation: the autologous pulmonary valve in the aortic position.
Aortic valve replacement (AVR) with a pulmonary valve autograft (PVA) was first reported by Donald N. Ross (DNR) in 1967. The expectation of this procedure was to avoid degenerative changes seen in other biological tissue valves such as calcification, attenuation, and rupture of the leaflets. Recent reports by the original investigator's group have confirmed the lack of degenerative changes in PVA. To corroborate their conclusions, the fate of 12 patients undergoing AVR with PVA by one of us (LGL) has been ascertained. From March 1969 to June 1971, 12 patients underwent AVR with PVA. The right ventricular outflow tract (RVOT) was reconstructed with an aortic homograft valved conduit. The mean age was 42.7 years (range 21 to 52 years). The mean follow-up for 11 hospital survivors is 12.4 years. Three PVA have been replaced; one following infective endocarditis at 13 years, and two at 15 and 73 months due to technical malalignment. There was no evidence of PVA degeneration during histological examination of these explanted PVAs. Six patients are alive and retain the original PVA at 12 years (55%). This analysis corroborates the conclusions of the DNR report and strongly suggests an immunological mechanism in the process of calcification of other biological tissue valves. The Ross operation is advocated for AVR in young patients as valve durability is of paramount importance especially in this group.
Adult↗
Morbidity following the Ross operation.
Aortic valve replacement (AVR) with a pulmonary valve autograft (PVA) was first reported by Donald N. Ross in 1967. The expectation of this procedure was to avoid degenerative changes seen in other biological tissue valves such as calcification, attenuation, and rupture of the leaflets. Recent reports by the original investigator's group have confirmed the lack of degenerative changes in PVA. To corroborate their conclusions, the fate of 12 patients undergoing AVR with PVA by Dr. Gonzalez-Lavin has been ascertained. From March 1969 to June 1971, 12 patients underwent AVR with PVA. The right ventricular outflow tract (RVOT) was reconstructed with an aortic homograft valved conduit. The mean age was 42.7 years (range 21 to 52 years). The mean follow-up for 11 hospital survivors is 12.4 years. Three PVAs have been replaced; one following infective endocarditis at 13 years, and two at 15 and 73 months due to technical malalignment. There was no evidence of PVA degeneration during histologic examination of these explanted PVA. Six patients are alive and retain the original PVA at 12 years (55%). This analysis corroborates the conclusions of Dr. Ross and strongly suggests an immunological mechanism in the process of calcification of other biological tissue valves. The Ross operation is believed to be the preferred method of AVR in young patients.
Adult↗
Homograft valve preparation and predicting viability at implantation.
An experimental study was performed using C14 proline uptake in order to: (1) assess the effects of current sterilization and storage methods on fibroblast viability, and (2) establish a control tissue that could be used to determine viability of each homograft valve at the time of implantation in the clinical setting. The results were expressed as disintegrations per minute per milligram of tissue (DPM/mg). Swine aortic (AV), pulmonary (PV), and tricuspid leaflets (TV), and adjacent AV and PV arterial wall were procured sterile and subjected to routine sterilization and storage. Thirty samples of AV were analyzed for incorporation of labeled proline at procurement (208 +/- 7 DPM/mg), following 48-hour antibiotic exposure (87 +/- 6 DPM/mg, P less than .0001), and following controlled rate cryopreservation and storage for 12 days at -80 degrees C (78 +/- 8 DPM/mg, P = .42). Proline uptake of the other tissues at the same intervals disclosed that only the TV resulted in the same degree of viability at implantation (AV 78 +/- 8, PV 68 +/- 3, TV 75 +/- 2, P = NS). The homograft valves were obtained under sterile conditions from brain dead, multiorgan donors (homovital). It has been postulated that these valves are sterile and ready for implantation. Of 17 homovital valves cultured at procurement, 9 had positive cultures within 48 hours (53%). We conclude that: (1) the TV can be processed as a control tissue with each homograft and then utilized to predict viability at the time of implantation in the clinical setting; (2) antibiotic exposure is an essential step in the preparation of all homografts, however, modification of the antibiotic solution is necessary.
Carbon Radioisotopes↗
The radiology of cardiac valve prostheses.
The radiographic findings associated with the complications of valve implantation are presented. Complementary roles of echocardiography and cine fluoroscopy in the recognition of complications associated with this procedure are emphasized. Identification of prosthetic valves and the knowledge of the modes of action of the various types of valves are stressed.
Bioprosthesis↗
Light and electron microscopic localization of atrial natriuretic peptide in the heart of spontaneously hypertensive rat.
Atrial natriuretic peptide (ANP) is a newly discovered peptide hormone present mainly in the atria. We investigated the occurrence and distribution of ANP immunoreactivity in the myocardiocytes of the ventricles of spontaneously hypertensive rats by use of immunocytochemistry at both light and electron microscopic level. ANP immunoreactivity was found in the specific granules in the cytoplasm of the cardiocytes in the subendocardium and the myocardium of the ventricles, as well as in the atria. The specific granules found in the ventricles of hypertensive rats were similar in size, shape, and ANP immunoreactive content to those in the atria. The abundance of ANP immunoreactivity in the left ventricle is greater than that in the right, and appears to increase with increasing severity of hypertension. Conversely, the overall content of ANP in the atria of hypertensive rats was decreased when compared with that in age-matched normotensive rats. The present findings indicate that ventricles may become a major source for ANP synthesis and release during hypertension, and may play important roles in cardiac endocrine pathology and cardiac hypertrophy.
Animals↗
Early-phase events with the mitroflow pericardial valve.
From January 1986 to January 1987, 116 Mitroflow pericardial valves were implanted in 98 patients at our center. Ages ranged from 10 to 83 years (mean, 64.9 years). Forty-three patients (44%) were in New York Heart Association Functional Class III or IV at the time of surgery. Twelve patients (12%) had undergone prior cardiac surgery. Ten hospital deaths (10%) (70% Confidence Limits, 7% to 14%) occurred. Incremental risk factors for hospital death included female gender (p = 0.08), higher functional class preoperatively (p = 0.04), and longer cardiopulmonary bypass time (p = 0.05). All 88 hospital survivors (100%) were followed for 6 to 13 months (mean, 9 months) after repair. Two late deaths (2.3%) occurred: 1 at 1.5 months from subacute cardiac failure, and another at 5 months from non-valve-related sepsis. Actuarial survival at 15 months was 87% +/- 5.5%. No late reoperations were performed. One patient who exhibited mild mitral incompetence 4 months postoperatively is being followed closely. Two patients (2.3%) who were not on anticoagulant therapy developed thromboembolic events in association with chronic atrial fibrillation. No patient has had hemolysis or infective endocarditis. All patients are now in Functional Class I or II. Our early-phase assessment of this valve reveals a low risk of valve-related events. Its low-profile frame and wide, flexible sewing ring make this prosthesis technically satisfactory for implantation. Continuing close follow-up will determine intermediate-and late-phase hazards.
Journal Article↗
Instantaneous risk of events following aortic valve replacement with pericardial valves: a ten-year experience.
Actuarial curves and linearized rates of occurrence are statistical functions that traditionally have been used to evaluate freedom from, or incidence of, valve-related events that occur as a result of aortic valve replacement (AVR); however, the instantaneous risk of an event can be more precisely pinpointed by the use of a time-related hazard function. This function was used to analyze 240 cases involving patients who underwent AVR with the Ionescu-Shiley bovine pericardial valve. Follow-up was for 10 years. The period from 60 to 70 months after implantation was apparently critical, since specific and cumulative events (intrinsic tissue failure, thromboembolism, prosthetic valve endocarditis, cumulated events, and death due to valve-related events) peaked during this period. We suspect important degenerative bioprosthetic changes take place during this period and are the cause, in part, for this pattern. In an effort to reduce the incidence of thromboembolism, close observation, and probably antiplatelet drug administration, should be initiated 60 months after implantation of this valve.
Journal Article↗
Safety of the right atrial approach for combined mitral and tricuspid valve procedures.
Patients undergoing operation for combined mitral and tricuspid valvular disease may have the repair performed through the right atrium and the interatrial septum. Although the transseptal method is an established procedure, recent reports have stressed the disadvantages of this operation and underscored the risk of the development of complete atrioventricular dissociation with this technique. A review of our results with this approach confirms the efficacy and safety of this method. The surgical protocols used are described.
Female↗
Determination of the need for a ventriculotomy in the repair of tetralogy of Fallot.
Fifty-two patients with tetralogy of Fallot underwent repair between March 1985 and July 1987. The repair was made without a ventriculotomy whenever feasible. There were no (0%) early or late-phase deaths (70% confidence limits 0% to 3.6%). Operative reports and preoperative angiocardiograms were retrospectively reviewed to delineate determinants for operative approach. Two distinct morphologic subgroups were observed angiographically and confirmed intraoperatively. Thirty-two patients (62%) had severe hypertrophy of the infundibular septal structures. Each of these 32 underwent transatrial and transpulmonary repair of the infundibular stenosis, and 12 of them also required a limited ventriculotomy to enlarge a hypoplastic pulmonary valve anulus. The other 20 patients (38%) were found to have hypoplasia and not hypertrophy of the infundibular septum. Each of these required a formal transventricular approach to the repair with an infundibular patch inserted to relieve the infundibular stenosis. Right ventricular/left ventricular systolic pressure ratios after repair were not different between the groups (p = 0.79). In conclusion, tetralogy of Fallot was satisfactorily repaired by means of a transatrial and transpulmonary approach in two thirds of these patients. The avoidance of a ventriculotomy to accomplish repair may be suggested preoperatively by selective angiocardiogram and confirmed by intraoperative assessment. These findings have important implications for the development of treatment protocols.
Adolescent↗
Congenital heart disease: Dr. Robert Anderson's systematic, sequential analysis of morphologic features.
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Critical Care↗
Determining viability of fresh or cryopreserved homograft valves at implantation.
Studies of homograft valves in the past two decades have suggested that "viable" valves, i.e., those maintaining chemical and structural integrity of their leaflet intercellular matrix, have a better long-term function than nonviable valves. The most effective qualitative methods of assessing leaflet viability involve destruction of the valve leaflets; thus, these methods have been limited to random use in selected valves. A study was conducted in swine in an attempt to establish a control tissue which could be tested in place of the homograft leaflets, thereby determining viability levels of every valve clinically implanted and correlating the results with long-term clinical function. Thirty samples each of the aortic and pulmonary artery wall and tricuspid leaflet were compared with aortic and pulmonary leaflets. Utilizing the technique of C14-proline uptake, viability was assessed at procurement, following sterilization, and following cryopreservation and short-term storage. The tricuspid leaflet was found to retain the same level of viability as the aortic and pulmonary leaflets before and after the cryopreservation period. It was concluded that the tricuspid leaflet could be utilized as the control tissue.
Animals↗
Thromboembolic and other events following valve replacement in a pediatric population treated with antiplatelet agents.
To determine if anticoagulation therapy is necessary after valve replacement with the St. Jude Medical prosthesis in young subjects, 30 consecutive patients were studied. They ranged in age from 4 to 20 years, and each had undergone valve replacement some time between February, 1982, and June, 1984. There was 1 hospital death (3.3%; 70% confidence limits [CL] = 0.4% to 10.9%). The 29 hospital survivors were treated with aspirin and dipyridamole. All patients were followed up. There were 5 late deaths (17.2%; 70% CL = 9% to 27%), at a mean of 8 months postoperatively. Follow-up revealed that 7 thromboembolic events occurred in 7 of the hospital survivors (24.1%; 70% CL = 15% to 35%). Hemiparesis occurred in 1 patient, and documented valve thrombosis and death occurred in another. Transient sensorimotor deficits were found in the 5 other patients. Prosthetic valve endocarditis developed in 1 hospital survivor (3.5%; 70% CL = 0.4% to 11%) and resulted in late death. There were no reoperations in the hospital survivors. We conclude that the St. Jude Medical prosthesis is useful for valve replacement in the young because of its low profile, durability, and hemodynamic characteristics. However, we recommend that these patients receive full anticoagulation therapy.
Adolescent↗
Tetralogy of Fallot repair with minimal or no ventriculotomy.
Twenty-four consecutive patients with the tetralogy of Fallot underwent repair from March 25, 1985 to March 24, 1986. Correction was achieved without a ventriculotomy in 8 patients, necessitated a minimal ventriculotomy in 8, and a formal right ventriculotomy incision was required in the other 8. There were no early or late phase deaths-0% (70% C.L. 0%-7%). Post repair right ventricular to left ventricular pressure ratios were not significantly different between the three groups (p = 0.85). The 16 patients (66%) who underwent repair without a formal ventriculotomy were found to have severe hypertrophy of the infundibular septum as the primary etiology for right ventricular outflow tract obstruction. The other 8 patients (34%), who required a transventricular approach to the repair, were all found to have predominantly hypoplasia of the outflow tract and not hypertrophy. We conclude that repair of the tetralogy of Fallot can frequently be accomplished with no or a minimal ventriculotomy, and the results are satisfactory. Herein is described the operative approach to this procedure.
Adolescent↗
Causes of failure and pathologic findings in surgically removed Ionescu-Shiley standard bovine pericardial heart valve bioprostheses: emphasis on progressive structural deterioration.
Twenty-three Ionescu-Shiley standard bovine pericardial bioprostheses (15 aortic, seven mitral, and one tricuspid) removed at surgery from 21 adults, 28 to 75 years old (mean 55 at reoperation), were examined after functioning for as long as 84 months (mean 26). Reoperation was necessitated by active or healed endocarditis (10 valves), paravalvular leak (three), structural deterioration (eight), and other causes (two). Valves with degenerative dysfunction functioned 32 to 84 months (mean 68). Six had intrinsic cuspal calcification, one with stenosis, and there was regurgitation through secondary cuspal defects in five. Six valves had cuspal defects clearly associated with commissural sutures ("alignment stitches") unique to this valve design. One valve had a large basal cuspal tear. Other prominent pathologic features included gross cuspal thickening and mild stretching and microscopic deep fluid insudation, separation of collagen bundles, and mononuclear inflammation. Thus, structural disruption due to calcific tissue degeneration and design-related cuspal tears or commissural perforations are the predominant modes of degenerative failure of Ionescu-Shiley standard bovine pericardial valves.
Adult↗