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Glutaraldehyde-preserved porcine bioprosthesis. Factors affecting performance as determined by pathologic studies.

The causes of porcine valve failure were evaluated pathologically in 129 bioprostheses (BP) removed at surgery or necropsy. Fifty-one BP had been in place for less than two months (early explants); most of the complications of this group were observed in the mitral position: left ventricular outflow obstruction (43 percent), thrombosis (23.5 percent), myocardial dysruption (20 percent), cardiac rupture (10 percent), and perivalvular leak (3.5 percent). Among the 78 explants in place for more than two months (late explants), 66 had evidence of dysfunction. Calcification was the leading cause of failure (46 percent), followed by thrombosis (17 percent), endocarditis (12 percent), fibrous tissue overgrowth (10 percent), perivalvular leak (9 percent), and primary cusp tears (6 percent). Calcific degeneration is a hallmark of the phenomenon of biodegradation, and experimental animal models are encouraged since they may represent the clue to preventing calcification and therefore enhancing performance and durability of the porcine BP.

Adolescent↗

Supravalvular and valvular aortic stenosis in homozygous familial hypercholesterolemia.

Premature atherosclerosis with a particular predilection to the coronary arteries is a well-known complication of homozygous familial hypercholesterolemia. However, well documented involvement of the aortic root and valve with aortic stenosis has not been recognized frequently antemortem. Clinical, echocardiographic, hemodynamic and angiographic features of a case with valvular and supravalvular aortic stenosis secondary to homozygous familial hypercholesterolemia are described. Surgical relief of the left ventricular outflow obstruction was not attempted because of the patient's refusal.

Adult↗

Venous air embolism during home infusion therapy.

Venous air embolism (VAE) is a potential complication of surgical procedures as well as central venous access. There are several reports in the literature of VAE during the in-hospital use and placement of central venous access. However, we are unaware of previous cases of VAE in children who received home infusion therapy via central venous access. We report the occurrence of a VAE in a 2-year-old with a Broviac catheter for home intravenous antibiotic therapy. VAE occurred when a bolus of air was unintentionally administered as the mother removed the cassette from the pump when it was alarming air in line. The cassette and tubing had been placed into the pump without a fluid flush. After the tubing and cassette were removed from the pump, the air in the line was allowed to flow by gravity into the patient, resulting in the immediate onset of respiratory and neurologic symptoms. The mother administered 2 rescue breaths, and the child's color and breathing returned to normal over the next 2 minutes. After the child arrived in the emergency department, the child's mental status returned to normal and the remainder of her physical examination was unremarkable. She had an uneventful recovery and was discharged from the hospital the following day. Additional antibiotic administration was accomplished in the emergency department of a local hospital. VAE can occur spontaneously when there is an open venous structure 5 cm or more above the heart or if air is delivered under pressure into the venous system, such as during a laparoscopy or mishaps with infusion bags. The morbidity and mortality of VAE are related to the volume of air, rate of entrainment, the patient's underlying cardiorespiratory status, and the patient's position. Morbidity and mortality occur as a consequence of right ventricular outflow obstruction or end-organ dysfunction from left-sided obstruction of coronary or cerebral vasculature as air passes across a patent foramen ovale or through the pulmonary circulation. Of all the literature pertaining to VAE with central lines, there are no previous reports of VAE occurring during home infusion therapy in children. With managed care requiring shorter hospitalizations and more children being discharged from the hospital on home infusion therapy, parents and lay caregivers are being asked to administer medications and perform routine maintenance on central venous devices. In our case, despite the fact that the mother had been educated regarding the appropriate technique for medication administration, she forgot to purge the air from the line before connecting the tubing and administering the antibiotic. Although the infusion pump will alarm when there is air in the line, it detects air only in a small part of the line and this safety feature is not in play if the device is removed from the infusion pump and administered via gravity. If such safety precautions are not adhered to, then the volume of air that fills the intravenous tubing from the drip chamber to the patient (25-30 mL in the pediatric infusion pump tubing used in our patient) can be infused by gravity into the patient's venous system. Because the consequences of VAE are so severe, the focus should be on prevention. Pumps used for home infusion therapy should have appropriate alarms to alert caregivers to the presence of air in the line. Obviously, this will not totally prevent this complication as this type of pump was used in our patient. It is crucial to educate caregivers of patients with central venous access regarding the hazards of VAE and safety measures to prevent it. With the increased use of home infusion therapy, ongoing evaluations of complications related to this form of therapy are mandatory so that there is continued evaluation of practices and appropriate changes made when necessary to increase further the safety of these techniques.

Cardiopulmonary Resuscitation↗

Craniopharyngiomas: an update.

Craniopharyngiomas have been challenging practitioners for over 100 years. These benign cystic tumors are thought to be a part of a continuum of ectodermal cystic lesions found in the suprasellar region. They are rare tumors found in both the adult and pediatric populations. Patients most often present with findings associated with ventricular outflow obstruction causing hydrocephalus, optic chiasm compression resulting in visual dysfunction or hypothalamic/pituitary compression leading to endocrinopathy. The mainstay of treatment involves a combination of radical or limited surgery followed by radiotherapy. Other adjunctive strategies include cyst fenestration, Ommaya catheter implantation and brachytherapy. Patients in general have high long-term survival but can have significant tumor- and treatment-associated morbidity requiring a lifetime of medical and psychological management.

Craniopharyngioma↗

Complete atrioventricular canal associated with tetralogy of Fallot. Successful repair using a new surgical technique. A case report.

A modified Mayo technique was successfully employed to correct a case of complete atrioventricular (a-v) canal associated with tetralogy of Fallot. The technique included: 1) separated patch closure of the atrial and ventricular septal defects, 2) attachment of the a-v valves between the two prosthetic septa without suturing the clefts, 3) mitral valve commissuroplasty, 4) relief of the right ventricular outflow obstruction. Postoperative catheterisation revealed normal haemodynamic findings. The child is asymptomatic two years after the operation.

Abnormalities, Multiple↗

Outcome of adults with repaired tetralogy of Fallot.

Outcome of adult patients with repaired tetralogy of Fallot (TOF) was studied with emphasis on postrepair problems. A retrospective review of clinical, echocardiographic, catheterization, and surgical data was performed for 48 patients who underwent corrective repair of TOF after 15 years of age. All patients survived total repair and have been followed up from 3 months to 11 years (median 4.6 years). Postoperatively, 81.3% of patients were in functional class I and 85.4% had normal right ventricular function. One patient (2.1%) died during follow-up. There were 6 reoperations (12.5%) in 5 patients. The indications for reoperation included residual ventricular septal defect (VSD) (n=1), right ventricular outflow obstruction with VSD (n=4), and pulmonary regurgitation (n=1). The 10-year actuarial survival rate was 97.1%, and the 10-year freedom from reoperation was 81.3%. Aortic regurgitation was seen preoperatively in 6 patients (12.5%) and there were 2 newly developed aortic regurgitations after operation, one of which was caused by infective endocarditis. Corrective repair of TOF can be recommended in this patient group since the survival rate, postrepair functional status and hemodynamics are acceptable. Continued close follow-up, however, is essential for early identification and correction of post-repair problems.

Adolescent↗

Echocardiographic estimation of aortic-valve gradient in aortic stenosis.

Fifty-five consecutive patients with aortic stenosis underwent echocardiography at the time of cardiac catheterization. Left ventricular systolic pressure was estimated from the echocardiogram assuming that peak systolic circumferential was stress was constant. Systolic blood pressure was substracted from the estimated left ventricular pressure to obtain the aortic-valve gradient. Of 44 patients with adequate echocardiograms and catheterization studies, 30 had their aortic gradient accurately estimated by the echocardiogram (r = 0.75). All 30 patients had normal left ventricular systolic function estimated echocardiographically. The echocardiogram underestimated the aortic gradient in all seven patients with poor left ventricular systolic function. An accurate echocardiographic estimate of aortic-valve gradient can be obtained in patients with normal left ventricular function. The technique can identify those patients with insignificant left ventricular outflow obstruction, thereby obviating the need for invasive studies.

Adolescent↗

Investigation of distal aortic compliance and vasodilator responsiveness in heart failure due to proximal aortic stenosis in the guinea pig.

Hypotension and syncope are recognized features of chronic aortic stenosis. This study examined vasomotor responses and dynamic compliance in isolated abdominal aortae after chronic constriction of the ascending aorta. Guinea pigs underwent constriction of the ascending aorta or sham operation. Sections of descending aorta were removed for studies of contractile performance and compliance. Dynamic compliance was measured using a feedback-controlled pulsatile pressure system at frequencies of 0.5, 1.5 and 2.5 Hz and mean pressures from 40 to 100 mmHg. Chronic (149+/-6 days) aortic constriction resulted in significant increases in organ weight/body weight ratios for left ventricle (58%), right ventricle (100%) and lung (61%). The presence of heart failure was indicated by increased lung weights, left ventricular end-diastolic pressure and systemic vascular resistance, reduced cardiac output and increased levels of plasma atrial natriuretic peptide (166%), adrenaline (x20), noradrenaline (106%) and dopamine (x3). Aortic rings showed similar constrictor responses to phenylephrine and angiotensin II, but maximal vasodilator responses to acetylcholine and isoprenaline were significantly increased (144% and 48% respectively). Dilator responses to sodium nitroprusside, forskolin and cromokalim were unchanged. Compliance of all vessels decreased with increasing pulsatile frequency and to a lesser extent with increased mean pressure, but were similar in aortic-constricted and control groups. Chronic constriction of the ascending aorta resulted in heart failure and increased vasodilator responses to acetylcholine and isoprenaline in the distal aorta while dynamic compliance was unchanged. We hypothesize that increased endothelium-mediated vasodilatation may contribute to hypotension and syncope in patients with left ventricular outflow obstruction.

Animals↗

Endovascular stent implantation in congenital heart defects.

We report the immediate and short-term results of endovascular stent implantations from our center. We performed stent implantations in four patients (3, 12, 18 and 20 years old) with different stenoses or obstructions: right ventricular outflow conduit obstruction, left Blalock-Taussig obstruction, post-operative recoarctation and cavopulmonary anastomosis obstruction. Stent were implanted successfully. The mean diameters of stenoses were expanded from 4.5 +/- 3.5 (2-7) mm to 9 +/- 1. 2 (8-10) mm, and the complaints of patients were improved significantly by stent implantation. There was no complication related to the procedures. All patients are living except one who died from cerebrovascular event unrelated to the stent implantation. The mean follow-up period of three living patients is 6.3 +/- 5.5 (1-2) months. As of the last control, all have remained at the caliber achieved at original placement. In light of our limited experience and previous reported studies, we conclude that intravascular stents are safe and can be used effectively in selected patients with congenital heart defects.

Adolescent↗

[Indications for and clinical outcome of the Ross procedure: a review].

The Ross procedure has been used increasingly to treat aortic valve disease in children and young adults. The primary indication for the Ross procedure is to provide a permanent valve replacement in children with congenital aortic stenosis. More recently, it has been extended to young adults with a bicuspid aortic valve and small aortic annulus, especially women wishing to have children. Other possible indications include complex left ventricular outflow obstructive disease, native or prosthetic valve endocarditis, and adult aortic insufficiency with a dilated aortic annulus. Conversely, Marfan syndrome is considered to an absolute contraindication, and this procedure should be used with caution in patients with rheumatic valve disease and a dysplastic dilated aortic root because of the higher associated incidence of autograft dysfunction. The technique of total aortic root replacement has become the preferred method of autograft implantation, because it carries the lowest risk of pulmonary autograft failure. In patients with marked graft-host size mismatch, either concomitant aortic annulus reduction and fixation or aortic annulus enlargement (i.e., the Ross-Konno procedure) should be performed. The Ross Procedure International Registry data document that in the modern era (post-1986) the early and late mortality rate is 2.5% and 1%, respectively. Excellent long-term results have been reported, and the benefits of this procedure include optimal hemodynamics, low risk of endocarditis, resistance to infection in patients with active endocarditis, and nonthrombogeneicity and therefore few anticoagulation-related complications. The Ross procedure can be performed with acceptable early and mid-term mortality and excellent autograft durability. Further long-term follow-up will confirm the role of this procedure in patients with various types of aortic valve disease.

Adult↗

Single coronary artery and sick sinus syndrome.

We report 2 patients with recurrent syncope and dizziness, later noted to have single coronary arteries. Both had right heart strain, one having pulmonary hypertension and the other having right ventricular outflow obstruction, which resulted in sinus node dysfunction. Patients were refractory to medical therapy and improved after pacemaker implantation.

Aged↗

Anomalous muscle bundle of the right ventricle. A report of seven cases.

It was within the last decade that right ventricular outflow obstruction due to anomalous muscle bundle was clearly described as a separate cardiac malformation seven cases of anomalous muscle bundle of the right ventricle were presented, and the diagnosis and surgical indications of this anomaly were discussed. The clinical differentiation of these patients from those with isolated VSD, pulmonic stenosis, and tetralogy of Fallot was not easy. Right ventriculograms that demonstrated the anomalous muscle bundle as a wedge-shaped filling defect are most useful for differentiation. All patients' anomalies were corrected with intracardiac surgery. The postoperative course was very satisfactory and all patients showed complete relief of the obstruction.

Adult↗

[Left ventricular papillary fibroelastoma associated with chief complaints of palpitation, general fatigue, and feverish].

Papillary fibroelastoma is one of the commonest benign tumor in the heart. In almost all of cases, symptoms never develop and the tumors are usually discovered coincidentally. Even though papillary fibroelastoma is a benign tumor, surgical extirpation is usually indicated for reason of productive serious complications. The tumors may cause left ventricular outflow obstruction, cerebral embolic infarction, myocardial infarction and even sudden death. The case we reported here is unusual case, because the patient developed symptoms and complaints such as palpitation, feverish and general fatigue. We measured tumor markers, interleukin 6, serotonin and histamine, but none of those was elevated in the blood samples. Surgical removal of the tumor attached to the base of posterior papillary muscle was carried out without causing mitral incompetence, and the pathological findings were compatible with papillary fibroelastoma. After the operation, the both symptoms and complaints disappeared unexpectedly.

Fatigue↗

[Mitral valve repair for a broad prolapse in the high posterior leaflet].

We report a mitral valve repair for a broad prolapse in the high posterior leaflet. Prolapse in the high redundant posterior leaflet with elongation of the chordae had caused the severe mitral valve regurgitation in a 45-year-old man. At operation, the prolapsed portion of the middle scallop was quadrangularly resected in 22 mm wide and 17 mm high. We combined the sliding leaflet technique with the posterior leaflet folding plasty to reduce the height of the posterior leaflet and to lessen the degree of mitral annular plication. Mitral valve regurgitation disappeared after the operation. No left ventricular outflow obstruction associated with systolic anterior motion and no injury to the left circumflex artery were confirmed. These procedures after a broad resection of the high posterior leaflet could successfully prevent systolic anterior motion and injury to the left circumflex artery, and reduce the stress on the suture line of the leaflet.

Cardiac Surgical Procedures↗

The preparticipation sports examination. Cardiovascular considerations for screening.

Physicians performing cardiovascular screening examinations in young and adult athletes should be aware of the rarity of exercise complications and the difficulty in separating cardiac adaptations to training from pathologic conditions. Coronary artery disease is the predominant cause of cardiac events during exercise in adults, whereas congenital abnormalities are the primary cause of exercise deaths in children. The preparticipation cardiac examination should include blood pressure measurements, visual inspection for the Marfan habitus, and auscultation designed to detect ventricular outflow obstruction. Other cardiovascular testing should be used when symptoms or findings warrant further evaluation.

Age Factors↗

[Changes in cardiac output during exercise in patients with hypertrophic cardiomyopathy: the study of these influences on exercise intolerance].

In order to investigate the relation between exercise intolerance and cardiac output (CO) increase during exercise in patients with hypertrophic cardiomyopathy (HCM), submaximal treadmill exercise (Sheffield protocol) with simultaneous measurement of CO and oxygen uptake (VO2) by acetylene rebreathing method were performed in twelve patients with HCM who had no demonstrable left ventricular outflow obstruction and fifteen control men. The measurements were made at rest, during exercise and recovery. 1) At rest cardiac index (CI) in patients with HCM was significantly less than in control subjects but the difference was small (HCM: 1.9 +/- 0.35 l/min/m2 vs control: 2.2 +/- 0.38, p less than 0.05), and was almost the same during light exercise (stage 1-3), but clearly increased during middle to submaximal stages (stage 4 and 5) (stage 5: 4.5 +/- 1.25 vs 8.0 +/- 1.30, p less than 0.01). 2) Heart rate was not different in both groups at rest, during exercise and recovery, which was considered to explain that the difference of CI was derived from that of stroke index (SI). 3) The change of VO2 showed the same tendency as that of CI. The difference increased considerably during the middle to submaximal stages (Stage 5: 15.3 +/- 1.42 ml/min/kg vs 25.4 +/- 4.42, p less than 0.01). 4) During recovery, CI and VO2 in patients with HCM indicated a delay of beginning to decrease toward the rest level, compared with control subjects. 5) VO2 was closely related to CI (r = 0.90, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

[Doppler echographic evaluation of pressure gradients of Björk-Shiley valve in the aortic position at rest and with exercise].

Pressure gradient across the Björk-Shiley (B-S) valve in the aortic position was assessed by Doppler echocardiography at rest and with exercise. There was close correlation between peak pressure gradient and area index which is a ratio of geometric orifice area (cm2) to body surface area (BSA) (m2). The correlation coefficient was -0.70 at rest and -0.86 with exercise. High peak pressure gradients with exercise were observed in the patients with 19 mm size (71 mmHg) and 21 mm size (107 mmHg). To avoid residual left ventricular outflow obstruction with exercise, it is considered advisable to use a #19 B-S valve in patients with BSA smaller than 1.1 m2, a #21 B-S valve in patients with BSA smaller than 1.4 m2, a #23 B-S valve in patients with BSA smaller than 1.8 m2, and a #25 B-S valve in patients with BSA smaller than 2.3 m2. If proper size of B-S valve cannot be inserted, aortic or aortic-mitral patch annuloplasty or the use of bileaflet valve are recommended as procedures of choice for small aortic annulus.

Aortic Valve↗