Search PubMed⌕ Search

Biomedical subjects

A Ahmadi

Publications and source records attributed to A Ahmadi.

At least 55 records · Page 3Linked to original sources
PubMed1995

Percutaneously adjustable pulmonary artery band.

BACKGROUND: Pulmonary artery banding, originally introduced to palliate increased pulmonary blood flow, is now primarily used for complex congenital cardiac defects with a prohibitive risk in the early repair, such as tricuspid atresia, or occasionally to prepare the left ventricle for eventual arterial switch. Conventional banding is, however, often poorly tolerated, and the precise adjustment required to reduced pulmonary blood flow or sufficiently challenge the left ventricle is difficult and can cause life-threatening hemodynamic changes. METHODS: We designed a band that allows accurate tightening and is reversible during the operation and at the bedside with the chest closed, allowing precise gradual adjustment over days, thereby minimizing cardiovascular instability. This design is the extension of previous work done by one of us on an adjustable annuloplasty ring. RESULTS: The band has been used for a 16-month-old child with tricuspid atresia type 1C who had undergone two failed attempts at banding. Hemodynamic measurements after 3 months confirmed achievement of the desired pulmonary pressure. CONCLUSIONS: This design, the simple insertion, and the ability to finely readjust the banding over days, combined with excellent patient tolerance, encourage further use of our adjustable band.

Constriction↗
PubMed1995

Intracytoplasmic sperm injection of mouse oocytes with 5 mM Ca2+ at different intervals.

The objective of this investigation was to determine whether intracytoplasmic sperm injection (ICSI) can be performed in the mouse. Metaphase II oocytes were obtained from F1 hybrid mice (C57BL x CBA) by i.p. injections of 10 IU pregnant mare's serum gonadotrophin (PMSG) and human chorionic gonadotrophin (HCG) administered 48 h apart. Oocytes with cumulus oophorus were retrieved 13-14 h post HCG. Cumulus was dispersed with 0.1% hyaluronidase. Mouse spermatozoa were obtained from the cauda epididymides of males of the same strain. The spermatozoa were processed by the standard swim-up procedure. The harvested spermatozoa were then incubated for 1.5 h to allow capacitation. Healthy oocytes were injected with 3-4 pl 5 mM Ca2+, followed by one live morphologically normal spermatozoon into the cytoplasm at intervals of 0, 0.5, 1, 2 and 3 h. The proportion of 2-cell embryos that developed from oocytes injected with Ca2+ and spermatozoa ranged between 29.5 and 36.5% in all groups, with no statistical difference between treatments. Chromosomal analysis showed that two-thirds of the ICSI-derived 2-cell embryos were diploid. The proportion of parthenogenetically activated embryos in the ICSI groups was similar to that in the control group (8-10%) which was injected with Ca2+ and polyvinyl pyrrolidone only. The proportion of blastocysts that developed in culture from the ICSI-derived 2-cell embryos was of the order of 36-42%. Some blastocysts were used for cell number counts. There was a significant increase in total and inner cell mass counts of blastocysts in which the spermatozoon was injected at 2 and 3 h following Ca2+.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Incidence of pseudoaneurysm after diagnostic and therapeutic angiography.

PURPOSE: To investigate prospectively with color flow duplex (CFD) sonography the incidence of pseudoaneurysm or arteriovenous fistula (AVF) after transfemoral arterial catheterization with angiography, percutaneous transluminal angioplasty (PTA), or local lysis (LL). MATERIALS AND METHODS: CFD sonography was used to examine the puncture site in 565 consecutive patients who had undergone PTA, LL, or angiography (581 procedures). RESULTS: The incidence of pseudoaneurysm in the first 300 procedures in which standard compression was used was 14.0% overall, 27.0% after LL with antegrade-puncture PTA, 18.5% after antegrade-puncture PTA, 9.3% after retrograde-puncture PTA, and 1.2% after angiography. To decrease the high incidence, in the next 281 procedures manual compression was continued for at least 5 minutes after local bleeding had stopped. This significantly reduced the incidence to 1.1% overall, 8.0% after LL in combination with PTA, 0.9% after antegrade PTA alone, 0.9% after retrograde PTA, and 0% after angiography (P < .01). CONCLUSION: The incidence of pseudoaneurysm after transfemoral arterial catheterization depends on the type of intervention. The main risk factor is too brief a period of manual compression.

Adult↗
PubMed1992

[Laser in surgery of vascular anastomoses].

The disadvantages of present-day microvascular suturing techniques include suture-induced foreign-body granulomas, stenoses and aneurysms. In comparison, argon laser-assisted anastomoses show a more favorable histomorphology and a low rate of stenoses and aneurysms. Laser-assisted anastomoses pass through the same familiar healing phases seen in common wound-healing.

Anastomosis, Surgical↗
PubMed1990

Special problems in Fontan-type operations for complex cardiac lesions.

Four patients with complex cardiac lesions, who underwent successfully a Fontan type of operation are presented, each case representing a particular problem in surgical management. The first exhibited displacement of a trileaflet straddling and overriding left atrioventricular valve in addition to tricuspid atresia, while the second one had unilateral lung perfusion. In the third case, a stenosis had developed near the origin of the right pulmonary artery, and pulmonary vascular resistance could not be determined prior to the definite palliation procedure, whereas the fourth patient presented with stenosis of the left atrioventricular valve. Surgery was planned after detailed evaluation of the morphologic and hemodynamic features by means of echocardiography and cardiac catheterization. Our results illustrate the common tendency to extend the limits for modified Fontan procedures, which also includes revision of the original criteria for selection.

Cardiac Catheterization↗
PubMed1990

[Indications for replantation in psychiatric patients exemplified by hand replantation in a patient with schizophrenia].

After evaluating all criteria known about indications for replanting severed extremities, we found that mental retardation (with the exception of some conceivable isolated cases) and mental illness, i.e. psychosis, can no longer be considered absolute contraindications for replantation measures, due to the adequate therapeutic possibilities that are currently available.

Adult↗
PubMed1990

[Wrist joint arthroscopy in obscure post-traumatic symptoms].

Clarification of posttraumatic wrist complaints is relatively difficult. Symptoms are often dismissed as wrist sprain. In an arthrogram a communication between the inferior radio-ulnar joint and the radiocarpal joint may indicate an injury of the triangular disc. In elderly patients, however, this communication can be present due to degenerative changes. Arthroscopy helps to evaluate not only the condition of the triangular disc, but also the cartilage of the distal forearm, the proximal carpal row, and some of the intercarpal ligaments. The authors report the results of wrist arthroscopy in twenty patients. Clinical and radiological examinations cannot always reveal the cause of disorders of the wrist. In these cases the procedure of arthroscopy can be recommended for preoperative clarification of cases of obscure posttraumatic wrist symptoms.

Arthroscopy↗
PubMed1989

Atrioventricular septal defect with double-outlet right atrium.

A rare type of primum atrial septal defect is described in which the atrial septum deviated to the left, resulting in a double-outlet right atrium. The obstruction at the site of the small atrial septum defect led to an elevation of the left atrial mean pressure and to pulmonary arterial hypertension. The presence of mixed blood in the right atrium caused systemic arterial desaturation. A cleft in the septal leaflet of the left atrioventricular (AV) valve caused a left ventricular-right atrial shunt, which-added to the left-to-right atrial shunt--totaled 60% of the pulmonary circulating volume. Preoperative knowledge of the anatomic features facilitated surgical repair, which consisted in resection of the abnormal septum, construction of a new septum with a Dacron patch, and closure of the septal commissure of the left-sided AV valve.

Abnormalities, Multiple↗
PubMed1989

Successful palliation of the "absent" pulmonary valve syndrome by banding of the pulmonary trunk.

The "absent" pulmonary valve syndrome is associated with aneurysmal dilatation of the pulmonary trunk, stenosis of the ventriculo-arterial junction with or without malalignment of the outlet septum, and ventricular septal defect. When the outlet septum is malaligned, the morphology resembles that of tetralogy of Fallot. We report our experience with 4 infants with this syndrome. All were in severe respiratory distress and cardiac failure when first seen. Cardiac catheterization was performed at 0.5-4.5 months of age in 3 of them. In the other, the clinical and echocardiographic features were considered sufficient to establish the diagnosis. Banding of the pulmonary trunk was carried out at the age of 2.5-5 months. The distal pulmonary arterial pressure in 3 cases dropped to 12-19 mm Hg. These patients could be extubated within one week postoperatively. Their course 1-3 years later is excellent, with rare episodes of mild respiratory problems only and markedly diminished pulmonary insufficiency. One child, weighing 3250 g at surgery, whose pulmonary arterial pressure did not drop below 29 mm Hg, could not be weaned off the respirator. Corrective surgery was undertaken 17 days later, but the patient died of respiratory complications. Based on clinical and Doppler sonographic findings, on control catheterization data and on haemodynamic findings in 3 surviving infants and two further patients with an uneventful course who, as yet, have not undergone surgery, we conclude that the beneficial effect of banding is the combined result of reduced pulmonary arterial pressure and decreased pulmonic regurgitation.

Child, Preschool↗
PubMed1989

[Determining indications and tactics in managing the severely injured hand].

The repair of a severely damaged hand requires not only a surgeon's skillful knowledge of the functional anatomy of the hand and the importance of its various parts and their place in the total function, but also experience in microsurgery. One's goal is to extensively save functionally important structures. Besides stabilizing the bone structure, microvascular measures to maintain blood circulation have priority. On the basis of three case studies each with different accident mechanisms, the problems of repairing a severely damaged hand and the results are described. When diagnosing such a severely damaged hand, one must evaluate the functional results that can be expected after repairing the hand in order to decide whether to keep it or to amputate and provide a prosthesis.

Adult↗
PubMed1988

Left atrial isomerism combined with right-sided heart, common atrium, incomplete atrioventricular septal defect and partial anomalous systemic and pulmonary venous drainage. Report of a case with successful surgical correction.

Precise preoperative diagnostic clarification was accomplished in an infant with left atrial isomerism. The inner/outer arrangement of the pulmonary/systemic veins in relation to the posterior wall of the common atrium necessitated a specific baffle in order to prevent pulmonary or systemic venous obstruction. The development of a sick sinus syndrome six months after surgery is in keeping with the natural history of the disease.

Blood Vessel Prosthesis↗
PubMed1988

Hemodynamic changes following experimental production and correction of acute mitral regurgitation with an adjustable ring prosthesis.

The hemodynamic effects of acute mitral regurgitation (MR) were investigated using a newly designed adjustable mitral ring prosthesis with remote control mechanism, implanted in mongrel dogs. The prosthesis allows to dilate the mitral annulus from outside the beating heart, and to create reversible MR of any desired degree without injuring the mitral valve apparatus. Dilatation of the mitral annulus by 25% of its circumference led to MR of angiographic grade 3+. Left ventricular systolic pressure (LVSP) dropped by 20%; dp/dtmax of the left ventricle by 16% and forward cardiac output (CO) by 31%. Left ventricular enddiastolic pressure (LVEDP) rose by 41%. The amplitude of the v-wave of the left atrium (LA) doubled, and mean LA pressure rose by 33%. If correction was carried out within one hour, then all parameters returned to normal. Maintaining the same degree of annular dilatation for two hours led to a further marked deterioration of the hemodynamics. LVSP dropped by 40%, dp/dtmax by 32% and CO by 58%. LVEDP rose by 160%. The amplitude of the v-wave of the LA increased by 300% and mean LA pressure doubled. MR, as determined by contrast 2-dimensional echocardiography (2DCE) intraoperatively, further increased in severity during the second hour, though annular size remained unchanged. In contrast to correction after one hour, correction carried out after two hours led to a slow, and, even after 12 hours, incomplete recovery. Electron microscope studies suggest papillary muscle dysfunction as a major cause of these late and partially irreversible changes.

Animals↗
PubMed1988

[Late results of the surgical treatment of aortic isthmus stenosis by patch-plasty].

To assess long-term outcome after repair of coarctation of the aorta by the patch graft technique of Vossschulte, analysis of the follow-up studies of 66 patients was carried out. At the time of operation, all patients were older than one year of age, mean age 14.4 years (range 1 1/2 to 58 years). The follow-up examinations were performed at a mean of nine years (range five to 17 years) after surgery. Angiographic studies were carried out in all patients with hypertension (ten cases) as well as in those who had undergone surgery ten or more years previously (19 cases). Hypertension was attributed to recurrence of the stenosis in two patients, renal factors were considered responsible in three and in five patients the hypertension was regarded as essential. No patient showed evidence of aneurysm at the site of repair. The fact that this finding is in contrast with the results of other investigators seems most likely related to the surgical technique employed in which the integrity of the intimal membrane is vigently respected to avoid changes in the structure of the aortic wall.

Adolescent↗