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Biomedical subjects

C E Essed

Publications and source records attributed to C E Essed.

At least 37 records · Page 2Linked to original sources
PubMed1988

The Paceport catheter: a new pacemaker system introduced through a Swan-Ganz catheter.

We describe a new stainless steel, teflon-coated 2.4 F pacemaker wire with a flexible tip that can be introduced through an extra lumen of a specially designed 7.5 F Swan-Ganz catheter. The extra lumen opens at 19 cm from the tip of the catheter; this opening can be positioned in the right ventricular cavity. The pacemaker wire can be introduced at the time of insertion of the Swan-Ganz catheter or later when the need for ventricular pacing arises. The Paceport catheter was tested in 23 patients. Satisfactory ventricular pacing was achieved in 19 patients at thresholds between 0.5 and 4.0 mA (median 2.0 mA). The threshold increased by 1 mA during long-term pacing (8-24 hr). Attempts to use the pacemaker were abandoned when short runs of ventricular tachycardia developed upon introduction, while an exceptionally high threshold was observed in another patient. The Paceport system is recommended for patients who require hemodynamic monitoring and urgent ventricular pacing.

Adult↗
PubMed1988

Three-dimensional reconstruction of myocardial contrast perfusion from biplane cineangiograms by means of linear programming techniques.

The assessment of coronary flow reserve from the instantaneous distribution of the contrast agent within the coronary vessels and myocardial muscle at the control state and at maximal flow has been limited by the superimposition of myocardial regions of interest in the two-dimensional images. To overcome these limitations, we are in the process of developing a three-dimensional (3D) reconstruction technique to compute the contrast distribution in cross sections of the myocardial muscle from two orthogonal cineangiograms. To limit the number of feasible solutions in the 3D-reconstruction space, the 3D-geometry of the endo- and epicardial boundaries of the myocardium must be determined. For the geometric reconstruction of the epicardium, the centerlines of the left coronary arterial tree are manually or automatically traced in the biplane views. Next, the bifurcations are detected automatically and matched in these two views, allowing a 3D-representation of the coronary tree. Finally, the circumference of the left ventricular myocardium in a selected cross section can be computed from the intersection points of this cross section with the 3D coronary tree using B-splines. For the geometric reconstruction of the left ventricular cavity, we envision to apply the elliptical approximation technique using the LV boundaries defined in the two orthogonal views, or by applying more complex 3D-reconstruction techniques including densitometry. The actual 3D-reconstruction of the contrast distribution in the myocardium is based on a linear programming technique (Transportation model) using cost coefficient matrices. Such a cost coefficient matrix must contain a maximum amount of a priori information, provided by a computer generated model and updated with actual data from the angiographic views. We have only begun to solve this complex problem. However, based on our first experimental results we expect that the linear programming approach with advanced cost coefficient matrices and computed model will lead to acceptable solutions in the 3D-reconstruction of the myocardial contrast distribution from biplane cineangiograms.

Cineangiography↗
PubMed1988

Competition of coronary arteries and ventriculo-coronary arterial communications in pulmonary atresia with intact ventricular septum.

Pulmonary atresia with intact ventricular septum can be complicated by the presence of large ventriculo-coronary arterial communications which disturb normal myocardial perfusion. In the selection of patients for surgery the presence of these communications provides an additional problem. On the basis of previous cineangiocardiographic study, we performed a histopathological study of 16 cases. Twelve presented with ventriculo-coronary arterial communications and four only showed myocardial sinusoids. A tripartite right ventricle was seen in the latter group but not exclusively. It is shown that subepicardial coronary arterial pathology is exclusively present in cases with ventriculo-coronary arterial communications although not solely at a connection site between a communication and an artery. The affected coronary artery is itself focally abnormal and hypoplastic and can be blocked or even absent. The interruption of such an artery can also occur after birth and not necessarily at a site of connection with a communication. This implies that infants with communications either already have a coronary circulation partly or completely dependent on ventriculo-coronary arterial communications at birth or can develop such a condition in time. This hazard to myocardial perfusion, often compromised by a large "steal" from the aorta to the right ventricle, limits the choice of surgical procedures.

Child, Preschool↗
PubMed1988

Absence of somatostatin receptors in human exocrine pancreatic adenocarcinomas.

Somatostatin receptor frequency was evaluated in 12 human exocrine pancreatic carcinomas taken after surgery. The tumors were analyzed by receptor autoradiography on tissue sections and by in vitro binding techniques on tumor homogenates. None of the tested human pancreatic carcinomas was shown to possess specific somatostatin receptors. In comparison, five single tumors taken from rats transplanted with the rat pancreatic adenocarcinoma CA 20948 were found to contain specific high-affinity somatostatin receptors. Also, human endocrine pancreatic tumors, i.e., two insulinomas, did contain somatostatin receptors under identical experimental conditions. These data confirm previous results with other tumors, documenting the absence of somatostatin receptors in highly malignant human carcinomas. They also may represent an explantation at the molecular level for the lack of therapeutic effect of somatostatin analogues such as SMS 201-995 seen in patients with advanced exocrine pancreatic carcinomas.

Adenocarcinoma↗
PubMed1988

In vitro cyclic AMP induced phosphorylation of phospholamban: an early marker of long-term recovery of function following reperfusion of ischaemic myocardium?

Changes in myocardial membrane biochemistry and ultrastructure, determined shortly (2 h) after reperfusion of ischaemic myocardium, were compared with the long term (4 wk) recovery of regional myocardial function. Anaesthetised pigs were subjected to 30 min (n = 14, group I) or 60 min (n = 14, group II) of left circumflex coronary artery occlusion. Seven animals of each group were studied 2 h and the others 4 weeks after flow was reinstated. After 2 h of reperfusion, regional myocardial function was absent in both groups. At 4 weeks regional function had returned to normal in group I, but was still significantly depressed in group II. Biochemical studies after 2 h of reperfusion showed that a functional index of the cardiac membrane, the in vitro cyclic AMP dependent 32P incorporation into phospholamban, was 71 (SEM 9)% compared to non-ischaemic myocardium in group I and 31 (6)% in group II (p less than 0.05). After 4 weeks this index had completely recovered in group I, 114 (13)%, but a significant decrease to 79 (2)% could still be observed in group II (p less than 0.05). After 2 h of reperfusion as well as after 4 weeks of recovery the myocytes in group II were more severely damaged than in group I. This study suggests that determination of in vitro phosphorylation of phospholamban shortly after reperfusion of ischaemic myocardium may be of value in the prediction of long term recovery of regional myocardial function.

Animals↗
PubMed1988

Percutaneous balloon valvuloplasty for calcific aortic stenosis. A treatment 'sine cure'?

Twenty-five elderly patients with calcific aortic stenosis, 12 male (48%) and 13 female (52%), mean age 74.8 +/- 7.6 years, underwent percutaneous aortic balloon valvuloplasty between March 1986 and September 1987. Twenty-two patients (88%) were in class III-IV of the New York Heart Association, 13 (52%) had a history of previous angina and 7 (28%) of syncopal attacks. All patients had been considered either unsuitable or high-risk candidates for aortic-valve replacement because of age or associated diseases. Balloons of increasing size (area ranging from 1.3 to 3.8 cm2 during inflation) were successively passed retrogradely from the femoral artery and manually inflated to 3-7 atmospheres. Inflation duration ranged from 15 to 260 s (mean 40 s). Post-dilatation there were significant changes in left ventricular peak-systolic and end-diastolic pressures (P less than 0.00001 and P less than 0.01, respectively), mean systolic aortic transvalvular gradient (from 73 to 43 mmHg, P less than 0.000001), mean systolic aortic flow (from 176 to 208 ml s-1, P less than 0.0001) and aortic valve area (from 0.47 to 0.72 cm2, P less than 0.000001). Major complications included: in-hospital deaths of two patients (8%) admitted in cardiogenic shock; left haemiplegia (4%); transient haemianopia (8%); development of grade III aortic insufficiency (4%); and persistent complete atrioventricular block (4%). Complications at the puncture-site occurred in 7 patients (28%)--including two femoral pseudoaneurysms and the need for surgical removal of a balloon remnant after rupture in one patient. No local haemorrhagic complications were observed in the latter eight procedures, performed using a 16.5 French 100-cm long arterial introducer. At a mean follow-up of 13.0 +/- 5.0 months, an important functional improvement persisted in 14 patients (56%), no major changes in pre-valvuloplasty symptoms were observed in 3 patients (12%), while five patients (20%) required surgical treatment after a successful valvuloplasty because of recurrence of symptoms (late valve restenosis). Percutaneous aortic balloon valvuloplasty is a possible palliative therapy in elderly patients with calcific aortic stenosis. However, its inherent immediate risk, limited haemodynamic result and the possible development of valve restenosis at medium-term follow-up, suggest that the application of this technique should be limited to poor surgical candidates.

Aged↗
PubMed1988

The heart after surgery for congenital heart disease.

The pathology of the heart following surgical correction for congenital cardiac defects has not been fully explored. This study is based on valvar aortic stenosis, atrioventricular septal defect, complete transposition of the great arteries, and Fallot's tetralogy. Emphasis has been put on preexistent gross pathology, with histological verification, and postoperative complications. Among patients with aortic valve stenosis preexistent anomalies dominated (left ventricular hypoplasia, mitral valve abnormalities, left ventricular endocardial fibroelastosis). The findings suggest that the cases represent an extreme within a spectrum and could explain the late postoperative dismal results in patients suffering from congenital left heart obstruction. In patients with atrioventricular septal defects the important pathology related predominantly to the operative procedure (injury to the atrioventricular bundle, patch dehiscence at the site of the atrioventricular node, inadequate repair of the left atrioventricular valve leaflets) and to pulmonary obstructive vascular disease. In complete transposition of the great arteries, with or without ventricular septal defects, technical problems dominated. Obstruction of the systemic and pulmonic venous pathways, atrial dysrhythmia, and tricuspid valve injury were the most serious complications following Mustard's procedure. The Rastelli-type procedure was complicated by degeneration and calcification of the porcine valve and crowding of the left ventricle. The arterial switch was complicated by abnormal origin and course of the left circumflex artery, which led to kinking and myocardial infarction. In Fallot's tetralogy surgical complications (injury to the atrioventricular bundle and the tricuspid valve) were the most important. The study discloses that the heart after surgery for congenital heart disease cannot be considered without taking preexistent pathology into account. Careful preoperative investigations are mandatory, since most anomalies could have been detected and, hence, might have changed the operative result.

Adolescent↗
PubMed1987

Restenosis 3 months after successful percutaneous aortic valvoplasty. A clinicopathological report.

A 76-year-old man with severe, calcific aortic stenosis experienced recurrence of symptoms 3 months after a successful percutaneous aortic valvoplasty. Echo Doppler revealed a marked increase of peak aortic flow velocity as compared with the immediate post-valvoplasty value. The patient underwent an uncomplicated aortic valve replacement. Adjacent to fragmented calcification, histology demonstrated a scarring reaction which might well be a major factor in the restenosis process.

Aged↗
PubMed1987

Percutaneous aortic balloon dilatation for calcific aortic stenosis in elderly patients: immediate haemodynamic results and short-term follow up.

Eight elderly patients (mean (SD) age 72.6 (8.5) years) with severe calcified stenosis of the aortic valve were considered for transluminal balloon dilatation in the Thoraxcenter between March and November 1986. In one patient the procedure could not be performed because of technical difficulties. Balloons of increasing diameter (13-25 mm) were successively passed retrogradely from the femoral artery and manually inflated with pressures of 400-600 kPa (4-6 atmospheres). Post-dilatation, there were significant changes in left ventricular pressures (from 237/21 to 204/13 mm Hg), mean systolic gradient (from 66 to 41 mm Hg, systolic aortic flow (from 172 to 202 ml/s, and aortic valve area (from 0.47 to 0.74 cm2); the cardiac index did not increase significantly (from 2.4 to 2.5 l/min/m2). One patient developed a pseudoaneurysm at the site of the femoral artery puncture that required surgical repair two months after the procedure; one patient experienced an acute left hemianopia during the procedure but had almost completely recovered at discharge. Five patients maintained a clinical improvement at a mean follow up time of 4.5 months after the procedure; two patients underwent aortic valve replacement, one because of minimal haemodynamic improvement after aortic balloon dilatation and persistence of severe dyspnoea and the other because of late recurrence of symptoms caused by restenosis after a successful procedure. Aortic balloon dilatation provides an alternative treatment for patients who are poor surgical candidates for cardiac or extracardiac reasons. At this stage the limited haemodynamic improvements suggest that the treatment can only be regarded as palliative, although proposed technical advances may achieve better immediate results in the future. Long term follow up is needed to evaluate the usefulness of this technique.

Aged↗
PubMed1987

Spark erosion of arteriosclerotic plaques.

For the recanalization of occluded arteries by means of plaque ablation an electrical technique, called spark erosion, has been developed. In vitro tests have shown that well-defined holes can be produced easily in fibrous, collagenous and lipid plaques, with minimal thermal side effects. As the method is not, by its nature, selective in vivo application will require an additional guidance technique to avoid arterial perforation. For this purpose, the potential use of tissue impedance as a sensing parameter has been tested. Main advantages of spark erosion are that it is a well controllable, low cost and highly effective tissue ablation technique.

Animals↗
PubMed1986

Unguarded tricuspid orifice with two-chambered right ventricle.

Catheterization and anatomical data are presented of an infant with cyanosis due to a most unusual variant of unguarded tricuspid valve orifice in association with a two-chambered right ventricle. The inlet portion of the right ventricle ended blindly and was completely separated from the outlet portion by a muscular wall. The outlet chamber, which supported the pulmonary trunk, received its blood from the left ventricle through an outlet foramen. The condition is considered to be related to imperforate Ebstein's anomaly.

Cardiac Catheterization↗
PubMed1985

Studies on cumene hydroperoxide-induced lipid peroxidation in the isolated perfused rat heart.

In the isolated, perfused rat heart, lipid peroxidation, induced by cumene hydroperoxide (Cum OOH), is accompanied by the release of malondialdehyde (MDA). Using a modified perfusion technique resulting in the separate collection of coronary and interstitial effluent, it can be shown that upon Cum OOH (0.5 mM) perfusion there is an immediate release of MDA in the coronary effluent and a delayed release in the interstitial fluid, indicating the susceptibility and coronary vascular tissue towards free radical-induced lipid peroxidation. Perfusion with Cum OOH leads to an initial increase of the coronary flow and a depressed contractility followed by a cardiac arrest concomitantly with the onset of MDA release in the interstitial fluid. Finally, during prolonged perfusion the coronary flow diminishes and contracture of the heart muscle ('stone heart') develops. These phenomena resemble those occurring during the 'calcium paradox'. Although the contractility diminishes immediately after the perfusion with Cum OOH the tissue ATP level and energy charge (formula; see text) remain constant. From the moment of cardiac arrest the ATP and creatine phosphate levels gradually decrease and the energy charge drops simultaneously with the appearance of MDA in the interstitial fluid. In contrast to the calcium paradox there is no simultaneous increase in the myocardial AMP level. Various mitochondrial enzymes (cytochrome c oxidase, monoamine oxidase, carnitinepalmitoyltransferase I and palmitoyl CoA synthetase) were tested and not affected by Cum OOH perfusion. During the development of contracture after 20 min of Cum OOH perfusion massive contraction band necrosis of cardiac tissue occurs. However, overall protein release is lower when compared with the protein release during the calcium paradox.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides↗
PubMed1985

Vaporization of atherosclerotic plaques by spark erosion.

An alternative to the laser irradiation of atherosclerotic lesions has been developed. A pulsed electrocardiogram R wave-triggered electrical spark erosion technique is described. Controlled vaporization of fibrous and lipid plaques with minimal thermal side effects was achieved and documented histologically in vitro from 30 atherosclerotic segments of six human aortic autopsy specimens. Craters with a constant area and a depth that varied according to the duration of application were produced. The method was confirmed to be electrically safe during preliminary in vivo trials in the coronary arteries of seven anesthetized pigs. The main advantages of this technique are that it is simpler to execute than laser irradiation and potentially more controllable.

Aged↗