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Biomedical subjects

K Seo

Publications and source records attributed to K Seo.

At least 37 records · Page 2Linked to original sources

Definite improvement in left ventricular function at six years after the Takeuchi procedure.

We report a case of a six-year-old girl who underwent the Takeuchi procedure for anomalous origin of the left coronary artery from the pulmonary artery at the age of 4 months. The left ventricular function was severely deteriorated before the initial operation and at 6 years after the procedure showed a remarkable improvement. Mitral regurgitation disappeared during the 6 years. The intrapulmonary tunnel was sufficiently patent to provide adequate blood flow for the anomalous coronary artery. This patient showed supravalvular stenosis due to shrinkage and thickening in the equine pericardium used for reconstruction of the pulmonary artery, and this stenosis was successfully released by autologous pericardial patch angioplasty.

Cardiac Surgical Procedures↗

Effect of hemofiltrated whole blood pump priming on hemodynamics and respiratory function after the arterial switch operation in neonates.

BACKGROUND: Primed blood might have some deleterious effects on neonates during cardiopulmonary bypass (CPB) due to unbalanced electrolytes and inflammatory mediators. We hemofiltrated pump-primed blood before CPB to reduce inflammatory mediators and to adjust pH and the concentrations of electrolytes. The current study investigated the effects of hemofiltrated whole blood priming on hemodynamics and respiratory function after CPB in neonates. METHODS: Patients who underwent the arterial switch operation in the neonatal period for transposition of the great arteries with intact ventricular septum were chosen for this study. Seventeen patients underwent CPB with hemofiltrated blood priming (group HF) and 23 patients underwent CPB with nonhemofiltrated blood priming (group N). The concentrations of electrolytes and bradykinin and high molecular weight kininogen of the primed blood before and after hemofiltration were measured. At 4 hours after completion of CPB, the left ventricular percent fractional shortening, and the relation between the mean velocity of shortening and the end-systolic wall stress (stress velocity index), were measured by echocardiogram in 7 patients in group HF and 6 patients in group N. Alveolar--arterial oxygen tension difference (AaDO2) and respiratory index (AaDO2 divided by arterial oxygen tension) were measured at several points for 48 hours after CPB in all patients. RESULTS: Hemofiltration of the primed blood maintained electrolytes within a physiologic level and significantly reduced the concentrations of bradykinin (5,649 +/- 1,353 pg/mL versus 510 +/- 35 pg/mL, p < 0.05) and high molecular weight kininogen (52.7% +/- 3.2% versus 40.1% +/- 3.0% of normal plasma value, p < 0.05). The percent of fractional shortening at 4 hours after completion of CPB was significantly higher in group HF (n = 7) than in group N (n = 6) (22.0% +/- 0.7% versus 16.0% +/- 0.4%, p < 0.01). There was also a trend toward better stress velocity index in group HF than in group N (0.81 +/- 0.81 versus -2.17 +/- 0.45, p = 0.09). AaDO2 and respiratory index were significantly lower in group HF than in group N for 48 hours after CPB, respectively (p < 0.05). CONCLUSIONS: Hemofiltrated fresh whole blood used for CPB priming attenuated cardiac impairment at early reperfusion periods and reduced pulmonary dysfunction in neonates with transposition of the great arteries with intact ventricular septum. This therapeutic strategy may have an advantage in preventing lung and heart dysfunction in pediatric patients who need CPB priming with blood.

Cardiopulmonary Bypass↗

[Pulmonary outflow tract reconstruction with autologous tissue during the Ross procedure: right ventricular characteristics in mid-term follow-up].

BACKGROUND: The Ross procedure requires the interposition of prosthetic or homograft extracardiac conduits to establish ventricle-pulmonary artery connection (RV-PA). These materials usually require multiple reoperations because of conduit failure. To avoid the re-replacement of currently available conduits, usage of autologous tissue may be preferable to reconstruct RV-PA connection during the Ross procedure, especially in the pediatric age group. METHOD: Ten patients (mean age 8.7 years, range 2-23) with congenital aortic valve disease underwent the Ross procedure between June, 1996 and July, 1998. To establish RV-PA continuity, autologous aortic wall including aortic valve with a gusset of pericardial tissue was used in six patients, rolled pericardial conduit with fresh pericardial bicuspid valve in three and one direct anastomosis of pulmonary posterior wall onto the right ventricle with a fresh pericardial monocusp valved patch. All patient's postoperative courses were uneventful. All patients were followed up (mean follow-up period: 21.6 +/- 6.6 months) and postoperative right ventricular characteristics, cardio-thoracic ratio (CTR) on chest X-ray and pulmonary valve function were evaluated. RESULTS: Postoperative right ventricular end-diastolic volume, right ventricular ejection fraction and right ventricular end-diastolic pressure did not change significantly (RVEDV: 128 to 113% of normal, RVEF: 56.4 to 51.5%, RVEDP: 5.9 to 10.1 mmHg). Pulmonary regurgitation during follow-up was mild in six patients and moderate in four. However, CTR decreased significantly over time (preop.: 56.5% postop.: 58.5%, late period: 53.4%). CONCLUSION: Our results support the concept of the reconstruction of pulmonary outflow tract without foreign materials during the Ross procedure. Longer follow-up are necessary to define the possible limitation of this technique.

Adult↗

[Intra- and postoperative heart rate changes following propofol anesthesia; a comparison with isoflurane anesthesia].

Bradycardia during propofol anesthesia is well known, but bradycardia after propofol anesthesia has not been studied well. We compared perioperative heart rates in patients who had undergone gynecological surgery under lumbar epidural anesthesia supplemented with light general anesthesia using isoflurane and nitrous oxide in oxygen (Group Iso, n = 25) with those who had received lumbar epidural anesthesia supplemented with propofol (Group Prop, n = 25). The heart rates for the Group Prop were significantly lower (P < 0.05) than those for the Group Iso after the induction of anesthesia up to 2 hours after surgery. Two patients in the Group Prop developed bradycardia below 50 bpm 1 and 2 hours after surgery. In one of them intravenous atropine was necessary to treat bradycardia. We conclude that more attention should be paid to postoperative as well as intraoperative bradycardia in patients who receive propofol.

Anesthesia, Epidural↗

[Cerebral oxygenation during non-blood prime cardiopulmonary bypass in congenital heart surgery].

To analyze oxygen delivery to the brain and cerebral cellular oxygenation during non-blood prime and blood prime cardiopulmonary bypass (CPB), 22 patients undergoing cardiac surgery with CPB were studied by near infrared spectroscopy (NIRS) monitor (NIRO 500, Hamamatsu Photonics). NIRS can assess continuously cytochrome oxidase (Cyt.aa 3) which is the terminal enzyme of the intramitochondrial respiratory chain. Patients were grouped according to conditions of CPB management: one group underwent repair with non-blood prime (group A, n = 12); the second group underwent with blood prime (group B, n = 10). Body weights ranged from 5.5 kg to 58 kg in group A, and 2.9 kg to 16 kg respectively. CPB was maintained at flow rates between 100 to 150 ml/kg/min. and the acid-base management strategy was alpha stat in all patients. No neurological complication was observed. NIRS date were expressed as changes from baseline where cannulation was prepared. The lowest value of Cyt.aa 3 was -2.7 +/- 0.7 mumol/l in the group A, and -3.9 +/- 1.0 mumol/l in the group B. From the standpoint of changes in Cyt.aa 3, non-blood prime cases we studied were speculated to be within a safety limit. In order to define the definite safety limits, however, further studies including the reduction velocity of Cyt.aa 3 signal as well as the absolute value of the lowest Cyt.aa 3 concentration are required.

Brain↗

[Heparin monitoring during cardiopulmonary bypass in congenital heart surgery].

The Hepcon/HMS system automatically provides the activated clotting time and a whole blood heparin concentration. It also provides the adequate protamine dose by titration of protamine to heparin. 45 patients undergoing congenital heart surgery with cardiopulmonary bypass (CPB) were studied by the Hepcon/HMS device. We measured the heparin dose response before heparin administration, and the ration between the dose of protamine (ml) which was necessary for heparin neutralization at the termination of CPB and the dose of total heparin (ml) in each patient. The value of heparin dose response ranged 120-390 (mean 228) IU/kg. The ratio between protamine dose and heparin dose varied 0.11-0.99 (mean 0.55). There was a statistically significant correlation between the duration of CPB and this ratio (r = -0.51, n = 45, p = 0.0005). From the standpoint of variances in the value of heparin dose response, conventional way of the heparin administration according to the patient's body weight alone may cause inadequacy of anticoagulation during CPB. A dose of protamine determined by Hepcon device that is smaller than a conventional dose of protamine prevents inadvertent overdose and, therefore, can reduce the adverse effects excessive protamine has.

Adolescent↗

Sevoflurane and isoflurane reduce oxygen saturation in infants.

Volatile anesthetics are generally known to exert several influences on the respiratory system, but their direct effect on oxygen saturation as measured by pulse oximetry (SpO2) in infants remains unknown. In this study, 70 infants under 2 years of age who received general anesthesia were examined to determine the effects of several volatile anesthetics and nitrous oxide on SpO2. After endotracheal intubation, the subjects were ventilated using a Jackson-Rees circuit with oxygen, nitrous oxide, and either sevoflurane, enflurane, or isoflurane adjusted to twice the adult minimum alveolar concentration (MAC) for the agents when used in combination with 67% nitrous oxide. In all cases, the end-tidal carbon dioxide tension (PetCO2) was maintained within the same range (28-35 mm Hg). Significantly lower SpO2 values (paired t test, P < .05) were observed when the subjects were ventilated with oxygen, 67% nitrous oxide, and sevoflurane or isoflurane--but not with oxygen, 67% nitrous oxide, and enflurane--than when they were administered oxygen, 50% nitrous oxide, and the original concentration of each volatile anesthetic. These results suggest that sevoflurane and isoflurane have different effects from enflurane on gas exchange systems.

Anesthesia, Dental↗

Time course of endothelin-1 and adrenomedullin after the Fontan procedure.

BACKGROUND: The endothelium-derived vasoconstrictor endothelin (ET)-1 might contribute to the physiology of blood flow regulation and play a role in cardiovascular disease. Adrenomedullin (AM) is a potent vasodilator peptide that has major effects on cardiovascular function and has multiple biologic effects involved in cardiovascular homeostasis. Although pulmonary vascular resistance is known to be one of the most important factors to determine the indications for a Fontan procedure, the time course of the plasma cytokine before and after the Fontan procedure is not known. METHODS: Sixteen patients were divided into two groups, 8 patients (1 to 14 years) who had the Fontan procedure (atriopulmonary connection) and 8 age-matched controls who had biventricular repair with normal central venous pressure. Plasma ET-1 and adrenomedullin levels were measured in both groups immediately before cardiopulmonary bypass, immediately after cardiopulmonary bypass, and 6 and 24 hours after cardiopulmonary bypass. A thermodilution catheter was inserted during the operation, and mean pulmonary arterial pressure, pulmonary wedge pressure, and cardiac output were measured, and pulmonary vascular resistance was calculated at the same time points. Correlation between the plasma ET-1 levels and pulmonary vascular resistance data were obtained in the Fontan group. RESULTS: Plasma ET-1 levels in the Fontan group were elevated after operation and were higher than the control group at 6 and 24 hours after cardiopulmonary bypass. Plasma adrenomedullin in the Fontan group was lower than in the control group at 6 and 24 hours after cardiopulmonary bypass. A significant positive correlation was obtained between the plasma ET-1 and pulmonary vascular resistance data (r = 0.475). CONCLUSIONS: Imbalance between increased ET-1 and relatively decreased adrenomedullin after cardiopulmonary bypass in the Fontan procedure could contribute to dominant effects of ET-1, which might induce vasoconstriction after the Fontan procedure. ET-1 might play an important role in maintaining vasoconstriction after the Fontan procedure.

Adolescent↗

Alteration of cell wall composition leads to amphotericin B resistance in Aspergillus flavus.

An amphotericin B (AmB)-resistant mutant was isolated from a wild-type AmB-susceptible strain of Aspergillus flavus by serial transfer of conidia on agar plates containing stepwise increased concentrations of AmB up to 100 microg ml-1. The acquired resistance of mycelia was specific for polyene-antibiotics AmB, nystatin and trichomycin. Spheroplasts derived from the resistant mycelia were as susceptible to AmB as the wild-type. Chemical analysis of the cell wall revealed that levels of alkali-soluble and -insoluble glucans were significantly higher in the resistant mycelia as compared to those in the wild-type. When resistant mycelia were treated with SDS, they adsorbed as much AmB as wild-type mycelia. These results suggest that alterations in the cell wall components of mycelia, especially 1,3-alpha-glucan and protein complex in the outermost wall layer, lead to AmB resistance in A. flavus.

Amphotericin B↗

[A case of Bentall's operation for an 11-year-old patient with Marfan syndrome].

An 11-year-old girl who was diagnosed to have Marfan syndrome in her infancy, visited us with complaints of easy fatigability and chest discomfort. She was pointed out to have acute development of annuloaortic ectasia with severe aortic regurgitation and mild mitral regurgitation. She underwent replacement of the ascending aorta and aortic valve using composite graft with prosthetic valve (Bentall's operation) and circular annuloplasty of the mitral valve. Bentall's operation for infants and children is remarkably rare because in this generation, acute development of aortic dilatation leading rupture and dissection is quite infrequent while main death is caused by mitral regurgitation.

Aorta↗

[A case of supravalvular mitral ring].

A two-year-old girl with supravalvular mitral ring successfully underwent the excision of the ring. The preoperative echocardiogram showed supravalvular mitral ring and almost normal mitral leaflets. We paid attention not to injury mitral valve at the excision of the ring because supravalvular mitral ring adhered to the mitral valve.

Child, Preschool↗

Post-thymic maturation of migrating human thymic single-positive T cells: thymic CD1a- CD4+ T cells are more susceptible to anergy induction by toxic shock syndrome toxin-1 than cord blood CD4+ T cells.

To determine whether human CD4+ T cells undergo post-thymic maturation, we compared the susceptibility to anergy induction in human thymic CD1a- CD4+ single-positive (CD4+), cord blood (CB) CD4+, and adult peripheral blood (APB) CD4+ T cells by stimulation with toxic shock syndrome toxin-1 (TSST-1). Most TSST-1-induced T cell blasts derived from either T cell preparation expressed TCR Vbeta2, which determines the potential reactivity to TSST-1. Most thymic CD4+ T cell blast preparations exhibited little or no production of IL-2 and IL-4 after restimulation with TSST-1 and only marginal responses after stimulation with rIL-2 or a combination of PMA and calcium ionophore, while the APB CD4+ T cell blasts showed high responses to these stimuli. The responses of CB CD4+ T cell blasts to these stimuli varied, ranging from minimal to relatively high. Studies of DNA fragmentation showed that there was no significant cell death of thymic CD4+ T cell blasts. Most thymic CD1a- CD4+ and CB CD4+ T cells were CD38 positive. APB CD4+ T cell blasts derived from the CD38+ fraction and from the CD38- fraction exhibited equally high responses to restimulation with TSST-1. These results indicate that thymic CD1a- CD4+ and CB CD4+ T cells are inherently highly susceptible to anergy induction by bacterial superantigens and that thymic CD1a- CD4+ T cells are less mature than CB CD4+ T cells, suggesting that post-thymic maturation in thymic T cells migrating to the periphery is required for acquisition of full reactivity to antigenic stimulation.

ADP-ribosyl Cyclase↗

[Surgical management of patent ductus arteriosus in low body weight infants].

Between January 1980 and December 1994, seventeen premature infants weighing less than 2500 g underwent surgical management for the isolated patent ductus arteriosus (PDA). Indometacine therapy for closure of PDA was not effective for all these patients. In terms of the body weight at birth, they were divided into two groups; Group I (G-I) consisted of ten patients with birth weight less than 1000 g and Group II (G-II) of seven patients weighing more than 1000 g. The age at operation was 22.1 +/- 15.4 days in the G-I and 14.3 +/- 11.4 days in the G-II. The ductus was ligated in all patients but one of the G-II, in whom it was divided. There were five (50%) hospital deaths in the G-I and none in the G-II. The causes of death in the G-I were related to necrotizing enterocolitis (NEC) in two and infant respiratory distress syndrome (IRDS), acute renal failure, and broncho-esophagial fistula in each. The age at operation tended to be older in nonsurvivors rather than in survivors in the G-I (28.0 +/- 16.8 days vs. 16.2 +/- 14.0 days, respectively, but the difference did not reach significance). Before surgery, all patients in the G-I required mechanical ventilator support and nine of them were associated with IRDS. In contrast, only two patients in the G-II needed mechanical ventilation preoperatively. The postoperative period of intubation was also significantly longer in the G-I than in the G-II (51.6 +/- 35.2 days vs. 2.2 +/- 1.5 days, respectively, p < 0.05). In conclusions, the surgery for PDA can be safely performed even in small premature babies weighing less than 1000 g. When medical therapy for PDA is not effective in the premature patients, the surgical management should be considered as early as possible before their conditions become worse due to such critical complications as NEC, IRDS, and renal failure.

Cardiac Surgical Procedures↗

Early local recurrence of rectal cancer showing extremely rapid growth after curative surgery: report of a case.

We report herein the case of a 59-year-old woman who developed a local recurrence of rectal cancer which showed extremely rapid growth. The patient had undergone a curative low anterior resection with total mesoexcision, and was discharged on postoperative day 25 after an uneventful recovery. However, 2 months after the operation, she developed bleeding from the rectum during defecation, the quantity of which gradually increased. A colonoscopy performed during the fifth postoperative month revealed a circular tumor at the suture line. The tumor was unresectable because it had firmly invaded not only the sacrum, but also the right ureter. Despite the administration of 5-fluorouracil and leucovorin, the patient died of cancer 18 months after her initial surgery. Considering that local recurrence of rectal cancer does not usually occur within 1 year after surgery, this case is unusual because the local recurrence developed very early and showed extremely rapid growth, occupying the entire lumen of the rectum by the time it was detected by colonoscopy during the fifth postoperative month.

Colonoscopy↗

Hemodynamic effects of human atrial natriuretic peptide after modified Fontan procedure.

BACKGROUND: Reduction of pulmonary vascular resistance and maintenance of urine output are important after the modified Fontan procedure. Atrial natriuretic peptide (ANP) has the effects of a vasodilator (including the pulmonary arteries) and a physiologic diuretic, and newly synthesized human ANP is available. We measured plasma ANP levels before and after the Fontan procedure and examined the effects of human ANP on hemodynamic parameters after the Fontan procedure. METHODS: Eight patients, aged 2 to 15 years, underwent the Fontan procedure (atriopulmonary connection). Blood samples were taken before and 3 hours after operation, and plasma ANP levels were measured by radioimmunoassay. The correlation between central venous pressure and ANP was examined. Human ANP was infused intravenously at a dosage of 0.1 microg x kg(-1) x min(-1) for 1 hour after the Fontan procedure under controlled ventilation and another blood sample was obtained. Urine volume and central venous pressure were measured, and pulmonary vascular resistance and the cardiac index were calculated by the thermodilution catheter method before and after human ANP infusion. One hour after human ANP infusion was discontinued, the evaluation was repeated. No other diuretics were given and the infusion rates of catecholamine were kept constant during these measurements. RESULTS: Plasma ANP levels before and after the Fontan procedure were 29.1 and 54.9 pg/mL, respectively, and a positive correlation was obtained between central venous pressure and plasma ANP levels (r = 0.661, p < 0.05). Human ANP infusion significantly decreased central venous pressure and pulmonary vascular resistance, and increased urine volume and the cardiac index, whereas the plasma ANP level was elevated to 617.5 pg/mL. Systemic blood pressure did not change significantly. CONCLUSIONS: Atrial natriuretic peptide is secreted in response to elevated central venous pressure after the Fontan procedure, but its concentration might not be sufficient. Human ANP can be a therapeutic choice after the Fontan procedure as a physiologic diuretic and a pulmonary vasodilator.

Adolescent↗

Atrial septal displacement for repair of anomalous pulmonary venous return into the right atrium.

BACKGROUND: In the repair of anomalous connection of the pulmonary veins to the right atrium, the use of a baffle of pericardium to divert the pulmonary venous blood into the left atrium could cause pulmonary venous obstruction as a result of thickening of the pericardial patch. Anomalous pulmonary venous drainage to the right atrium caused by malposition of the atrial septum primum can be repaired by displacing the shifted septum primum to the normal position. METHODS: In 5 patients with total (n=2) or partial (n=3) anomalous pulmonary venous drainage into the right atrium, the septum primum was shifted toward the left atrium and the pulmonary veins drained into the anatomic right atrium despite their normal connection with the posterior wall of the left atrium. This method consisted of incision of the posterior edge of the atrial septum primum and displacement of the incised atrial septum between the anomalous pulmonary veins and both venae cavae. No patch was used. RESULTS: Postoperative echocardiography showed a wide pathway from the pulmonary veins to the left atrium with no stenotic portions. No atrial arrhythmias occurred after the operation. CONCLUSIONS: This technique may be advantageous because it allows for future growth of the route of the pulmonary venous pathway and avoids postoperative supraventricular arrhythmias.

Arrhythmias, Cardiac↗

Effectiveness of prenatal ultrasonography in detecting fetal anomalies and perinatal outcome of anomalous fetuses.

A retrospective study was performed over a 5-year period (1990-94) to evaluate the effectiveness of prenatal ultrasonography in terms of sensitivity, specificity, and predictive values in detecting fetal anomalies by comparing prenatal ultrasonic results with anomalies found in neonates and the perinatal outcome of anomalous fetuses. Minor congenital anomalies as listed and defined in the Eurocat Register were excluded. From a total of 5544 singletons, 4819 had at least one ultrasound scan (87%), of which 3004 at low risk and 1815 (38%) at high risk for anomalies had routine screening (RS) and indicated scanning (IS), respectively. A total of 136 fetuses were structurally abnormal (2.82%, RS and IS: 0.77% and 6.23%) and 200 major anomalies (RS and IS: 37 and 163) were recorded. The overall sensitivity of the ultrasound test was 78.7% (RS and IS: 34.8% and 87.6%, P < 0.01) for abnormal fetuses and 58.0% (RS and IS: 29.7% and 64.4%, P < 0.01) for anomalies. The overall specificity was 99.9% and the positive and negative predictive values were 97.3% and 99.4%, respectively; these values did not differ significantly between the two groups. The sensitivity of ultrasound for the detection of abnormal fetuses before 24 weeks was 22.8% (RS and IS: 13.0% and 24.8%) which was associated with a 61% (25/41) termination rate (RS and IS: 25% and 75.9%, P < 0.01) and a 24.4% (10/41) postnatal survival rate (RS and IS: 41.7% and 17.2%). The overall survival rate following pre- and postnatal correction of anomalies was 44.9% (RS and IS: 60.9% and 41.6%). For the detection of fetal anomalies anatomic ultrasound scanning is necessary during pregnancy, irrespective of pregnancy condition. Early detection of fetal anomalies could offer the option of pregnancy termination.

Abortion, Induced↗

Fate of trileaflet equine pericardial extracardiac conduit used for the correction of anomalies having pulmonic ventricle-pulmonary arterial discontinuity.

BACKGROUND: External conduits used for the repair of congenital heart diseases having discontinuity between the pulmonic ventricle and the pulmonary artery still carries a high risk of reoperation. Between June 1983 and June 1992, handmade equine pericardial conduit with fabricated trileaflet valve had been the conduit of choice in our institute. The aim of this study is to clarify the temporal sequence of conduit obstruction in this material and to formulate the optimal surgical strategies for this disease entity. METHODS: One hundred forty-three patients have undergone extracardiac conduit repair using this conduit. Postoperative catheterization performed within 2 months showed pulmonary to systemic ventricular systolic pressure ratio of 0.57 +/- 0.17 with the pressure gradient between pulmonic ventricle and pulmonary artery of 21.1 +/- 17.2 mm Hg. In 63 patients among the survivors, a series of Doppler two-dimensional echocardiographic images could be clearly obtained. RESULTS: Moderate-to-severe degree of pulmonary insufficiency represented only 3.2% of all cases within 3 months, which rapidly increased to 14.3% at 1 to 3 years and 32.8% at 3 to 5 years. However, the rate of increase of pulmonary insufficiency diminished beyond 5 years with 34.9% at 5 to 7 years and 40.0% at 7 to 9 years. Estimated pressure gradient calculated by Bernoulli's equation applied in the same patient subset was 4.1 +/- 7.9 mm Hg within 3 months, which progressively increased to 7.1 +/- 11.8 mm Hg at 1 to 3 years, 21.0 +/- 24.0 mm Hg at 3 to 5 years, 40.2 +/- 25.9 mm Hg at 5 to 7 years, and 71.3 +/- 34.0 mm Hg at 7 to 9 years. Among patients with a pressure gradient across the conduit of more than 40 mm Hg at follow-up catheterization, the primary cause of the obstruction was attributed to degeneration of the valve in 7 patients, whereas sternal compression was strongly suspected as the primary cause in the other 8 patients. Intimal peel was not obvious in the excised specimens. CONCLUSIONS: Degeneration of the valve in the equine pericardial conduit became prominent at 3 to 5 years after the operation, whereas the pressure gradient across the conduit continued to progress thereafter. A thick and hardened valve from degeneration and varying degrees of external compression by the sternum were delineated at the site of stenosis.

Animals↗