Clinical and hemodynamic follow-up of left ventricular to aortic conduits in patients with aortic stenosis

To assess the long-term results of left ventricular outflow tract reconstruction utilizing an apical left ventricular to aortic valved (porcine) conduit the clinical and hemodynamic data were reviewed from 24 patients who had placement of an apico-aortic conduit. Eighteen of the patients are asymptomatic and taking no cardiac medications. Three patients were reoperated on, one patient 1.5 years after his original operation for subacute bacterial endocarditis and two patients 3 to 4 years after their original operation for severe conduit valve insufficiency. None of the patients is taking anticoagulants and no thromboembolic events have occurred. Postoperative catheterization has been performed 1 to 1.5 years (mean 1.2) after repair in 15 of 21 patients. The rest left ventricular outflow tract gradient has decreased from 102.5 ± 20 mm Hg preoperatively to 14.8 ± 9.9 mm Hg postoperatively (probability [p] < 0.001). Some degree of conduit obstruction was demonstrated by catheter passage in 11 of the 15 patients. In these 11 patients, the obstruction occurred at three distant sites: at the egress of the left ventricle in 9, at the porcine valve in 5 and at the aortic to conduit junction in 1. Isometric exercise in five and supine bicycle exercise in six patients increased the left ventricular outflow tract gradient by 2.5 ± 1.1 and 20.8 ± 11.8 mm Hg, respectively, despite an increase in cardiac index of 1 ± 0.3 and 3.7 ± 0.4 liters/min per m2, respectively. The data suggest that a left ventricular to aortic conduit is an effective form of therapy for severe left ventricular outflow tract obstruction

Determination of myocardial and serum digoxin concentrations in children by specific and nonspecific assay methods

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/109866/1/cptclpt198378.pd

Ventricular Pacing in Children

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75351/1/j.1540-8159.1982.tb06565.x.pd

Potential for reversibility of pulmonary vascular obstructive disease in children after cardiac transplantation

Patients with pulmonary vascular obstructive disease (PVOD) are usually not considered candidates for orthotopic cardiac transplantation, because the normal donor's right ventricle may be unable to function because of an acute increase in afterload, especially in the postischemic situation of the arrested and transported donar heart. The accepted guideline is that pulmonary vascular resistance (PVR) must be 8 Wood units (mm Hg/liters/min) or lower during maximal medical management.1,2 Patients whose PVR is between 4 and 8 Wood units are marginal candidates. Combined heart-lung transplantation or heterotopic cardiac transplantation is generally believed to be necessary when the PVR is 8 units. However, among children with a variety of congenital defects, PVOD is often reversible after correction, especially when correction is performed at a young age. This was the case in the patient described herein whose cardiac transplantation was successful despite a PVR of nearly 13 Wood units.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25979/1/0000045.pd

Use of videotape to promote parenting of infants with serious congenital heart defects

Parents of infants with serious congenital heart defects have misconceptions and negative feelings which may threaten their ability to provide optimal care for their infant. In an effort to increase knowledge and promote a more positive, less anxious attitude among these parents, a videotape entitled `Your Baby with a Congenital Heart Defect' was developed and evaluated. Forty-three parents of thirty infants who required cardiac catherization in the first 8, weeks of life were randomly assigned to experimental (N = 23) or control (N = 20) groups. In the videotape viewed by the experimental parents, three families of cardiac infants related common feelings, problems and infant care experiences. The control group viewed a videotape describing the cardiac anatomy and functional changes associated with defects. Post-videotape questionnaires demonstrated significantly greater knowledge of the infant's behavior and needs in the experimental parents compared to controls (P P P P P = 0.02). We conclude that viewing the videotape on infant care improved parental attitude and their understanding of the behavior and needs of the neonate with congenital heart disease.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/25644/1/0000196.pd

Reoperation for coarctation of the aorta

Between 1957 and 1980 reoperation for coarctation of the aorta was performed in 21 patients at one institution for an overall incidence rate of 7.9 percent. The incidence rate of reoperation was 38 percent for patients younger than age 3 years and 1.5 percent for patients 3 years or older at initial repair. Before reoperation 14 of the 21 patients were symptomatic, 19 had systolic hypertension of the upper limbs and 20 had a documented coarctation pressure gradient at rest (mean 42.4 mm Hg). Surgical techniques used at reoperation were patch aortoplasty in 12 patients, graft interposition in 4, end to end anastomosis in 3 and end to side left subclavian to descending aorta bypass graft in 2. There was one surgical death. The 20 survivors have been followed up a mean of 4.3 years. There has been significant symptomatic improvement (p In conclusion, the incidence of reoperation is significantly increased in patients who are younger than age 3 years at initial coarctation repair. Reoperation is a safe and effective procedure. It has a low mortality rate (4.8 percent), relieves symptoms and decreases hypertension and the coarctation pressure gradient. Patch aortoplasty appears to be the operative procedure of choice. Moderate to severe hemodynamic abnormalities may persist during exercise after reoperation for coarctation of the aorta.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24189/1/0000448.pd

A quantitative and qualitative comparison of fibrin glue, albumin, and blood as agents to pretreat porous vascular grafts

Recent reports suggest that fibrin glue can be used to seal porous vascular grafts prior to insertion, but this ability has not been quantitatively compared to existing methods. We compared blood loss from and handling characteristics of grafts pretreated with either fibrin glue (FG) (Tisseel), albumin autoclaving (AA), or blood preclotting (BP). Five 6-cm segments of 6-mm internal diameter grafts, both knitted and woven double velour Dacron were treated in each group (30 specimens). Human blood was forced through the BP group until clotted; AA segments were soaked in 25% human albumin and autoclaved for 10 min; FG segments were treated with a topical application of Tisseel (0.5 ml/graft) followed by treatment with topical thrombin + CACl (0.5 ml/graft). Graft ends were sealed and attached to a transducer/syringe pump mechanism which pumped heparinized human blood into the graft at 100 mm Hg intraluminal pressure. All blood that leaked through the grafts over 2 min was collected and the amount was averaged for the five grafts in each group. Graft handling was characterized as either pliable or stiff. Blood pretreatment caused 21 +/- 2 and 13 +/- 4 cc/2 min of leak in knitted and woven grafts, respectively. Albumin autoclaving resulted in 9 +/- 2 and 1 +/- 0.5 cc of leak (P P &lt; 0.01 compared to blood). Both blood and fibrin glue produced soft pliable grafts, while albumin pretreatment resulted in stiff grafts. We conclude that fibrin glue or albumin is superior to blood for pretreatment of woven grafts in limiting blood loss, but that fibrin glue is superior to either albumin or blood in knitted grafts. Fibrin glue imparts superior handling characteristics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26651/1/0000195.pd

Simultaneous visualization of flow fields and oxygen concentrations to unravel transport and metabolic processes in biological systems

From individual cells to whole organisms, O2 transport unfolds across micrometer- tomillimeter-length scales and can change within milliseconds in response to fluid flows and organismal behavior. The spatiotemporal complexity of these processes makes the accurate assessment ofO2 dynamics via currently availablemethods difficult or unreliable. Here, we present ‘‘sensPIV,’’ a method to simultaneously measure O2 concentrations and flow fields. By tracking O2-sensitive microparticles in flow using imaging technologies that allow for instantaneous referencing,we measuredO2 transport within (1) microfluidic devices, (2) sinking model aggregates, and (3) complex colony-forming corals. Through the use of sensPIV, we find that corals use ciliary movement to link zones of photosynthetic O2 production to zones of O2 consumption. SensPIV can potentially be extendable to study flow-organism interactions across many life-science and engineering applications

Excitation of the double chamber right ventricle: Electrophysiologic and anatomic correlation

To examine the excitation of the double chamber right ventricle and the possibility that it results from a displaced, hypertrophied moderator band, seven patients with double chamber right ventricle were studied. All seven had pre- and postoperative electrocardiograms. Intraoperative right ventricular epicardial maps were obtained in three; right ventricular endocardial activation maps performed at postoperative catheterization were obtained in four. In the three patients studied at operation the breakthrough point of right ventricular epicardial activation was demonstrated in a normal inferior location well below the obstructing muscle band. Two patients with right bundle branch block after operation and two others with only right ventricular conduction delay on postoperative electrocardiogram demonstrated high normal right ventricular time with prolongation of activation in the right ventricular outflow or inflow region, or both, suggesting only peripheral injury. These data suggest that activation of the double chamber right ventricle is similar to that of the normal heart. In addition, the observed normal activation sequence militates against the hypothesis that the moderator band is the obstructing bundle.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24028/1/0000277.pd

Transposition of the great arteries, right aortic arch, coarctation, and isolation of the left subclavian artery: Report of surgical therapy

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/24449/1/0000723.pd