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Biomedical subjects

A Piwnica

Publications and source records attributed to A Piwnica.

At least 127 records · Page 7Linked to original sources
PubMed1982

[Fluorocarbons: applications to cardiovascular surgery (author's transl)].

Fluorocarbons are synthetic compounds capable of dissolving large amounts of gases (O2, CO2, N2, CO). The current availability of stable O2- carrying emulsions delivering substantial volumes of this gas to perfused tissues makes it possible to extend the potential clinical use of perfluorochemicals. In cardiology, fluorocarbons have proven experimentally efficient during cardiopulmonary bypass as blood substitutes, in cardioplegic and reperfusion solutions and as agents designed to reduce the size of acute myocardial infarcts. However, a more thorough understanding of their long-term effects on cells is needed before their routine clinical use can be considered.

Animals↗
PubMed1982

Retrograde coronary sinus perfusion: a safe alternative for ensuring cardioplegic delivery in aortic valve surgery.

During aortic valve surgery, cardioplegic solution is delivered through direct cannulation of both coronary ostia. Since this approach may cause an intimal injury leading to acute dissection or late ostial stenosis, we have evaluated retrograde coronary sinus perfusion (RCSP) as a means of delivering cardioplegia in 12 patients undergoing aortic valve replacement. The retroperfusion of the cardioplegic solution was performed with a balloon-tipped catheter inserted into the coronary sinus through the right atrium. The perfusion pressure averaged 40 mm Hg. Twelve patients undergoing antegrade coronary perfusion served as controls. Both groups were matched for preoperative and intraoperative data. The postoperative evaluation focused on hemodynamic status, as evidenced by serial measurements of right-sided pressures and cardiac output at 1, 6, 12, 18, and 24 hours after operation. The stroke volume index and the left ventricular and right ventricular systolic stroke work indexes were then calculated. There was no statistically significant difference between the two groups. We conclude that RCSP is a simple, safe, and effective means of cardioplegic protection during aortic valve surgery.

Adult↗
PubMed1982

Acute left ventricular rupture secondary to myocardial infarction. Report of long-term survival after early surgical repair.

The case of a 53-year-old male patient is presented who experienced acute left ventricular rupture 12 hours after a myocardial infarct. Immediately following emergency right heart catheterization and pericardiocentesis the patient was operated upon after preliminary institution of femoro-femoral partial heart-lung bypass. Left ventricular rupture in the area of an apical infarct was found which was successfully treated by direct closure. The patient made a complete recovery subsequent to a complicated postoperative course.

Cardiopulmonary Bypass↗
PubMed1982

[Coarctation of the thoraco-abdominal aorta. Problems of surgical methodology].

Coarctations of the thoraco-abdominal aorta are rare malformations. Whilst determining the need for surgery, in general because of hypertension, raises few problems, the choice of surgery tactics gives rise to discussion. The choice must above all take into account the risks of visceral ischaemia, in particular affecting the spinal cord, the causes of which are at one and the same time technical (total aortic clamping, sacrifice of the intercostal arteries) and haemodynamic (blood pressure variations). Under such conditions, it would seem necessary to reject resection-suture. Discussion is thus limited to aortoplasty with a widening patch, which is suitable in particular for short stenoses of easy access and to by-pass from ascending aorta to abdominal aorta, electively more indicated in cases of extensive coarctation with severe periaortitis, though the long-term fate of such by-passes remains uncertain.

Adult↗
PubMed1982

[Aorto-left ventricular discontinuity of infectious origin. Problems of surgical repair].

Aorto-left ventricular discontinuity may result from destruction of the aortic ring in aortic valve endocarditis, making solid implantation of a valvular prosthesis difficult. We believe the best technique to be the insertion of a valved Dacron tube from a noninfected area of the left ventricle to the ascending aorta distal to the coronary ostia, the coronary arteries being reimplanted in the tube. This technique implies a relatively dilated aortic ring and the integrity of the supra-annular aortic wall. When these conditions are not fulfilled, the problem has to be solved by supra coronary implantation of an aortic prosthesis with double aorto-coronary bypass grafts. Valved tubes from the left ventricular apex to the abdominal aorta is complex major surgery, the indications for which should be limited to the most mutilating forms of endocarditis causing such severe annular and periannular lesions that the two preceding techniques are impossible. Despite the advances in surgical technique, operative mortality remains high, a problem that could undoubtedly be reduced by early surgery before the association of hemodynamic and infectious complications lead to severe cardiac failure and widespread local lesions.

Aortic Valve↗
PubMed1982

Nuclear magnetic resonance: a new method for non-invasive assessment of cardiac metabolism.

In the setting of cardiac testing, NMR spectroscopy should occupy a major place since it allows a noninvasive serial assessment of the biochemical status of a functioning heart and could be coupled with other investigations to provide simultaneous recordings of both metabolic and functional data from a definite myocardial area. In the future, NMR imaging may become a clinically viable tool providing localized non-invasive biochemical measurements in the heart.

Coronary Disease↗
PubMed1981

[Applications of carbon to cardiovascular biotechnology (author's transl)].

Carbon is now being widely used in cardiovascular biotechnology. It has both remarkable physical properties, being strong and resistant to fatigue and wear, and high haemocompatibility owing to the almost complete lack of interaction between carbon surfaces and blood proteins. At present, carbon is predominantly used in synthetic heart valves, but its use could be soon extended to vascular prostheses or even to extracorporeal circulation.

Biocompatible Materials↗
PubMed1981

[A new method to evaluate myocardial preservation techniques (author's transl)].

Nuclear magnetic resonance (NMR) is a non-invasive technique which, when using 31Phosphorus (as is usually the case), provides sequential determinations of the concentrations of high energy phosphate compounds and of intracellular pH in tissues subjected to electro-magnetic pulses. NMR can now be applied to the whole heart and makes it possible to record simultaneously biochemical and haemodynamic data. Referring to personal cases, the authors emphasize the value of NMR as a new device for evaluating myocardial preservation techniques during both ischaemia and reperfusion.

Adenosine Triphosphate↗
PubMed1981

Limitations of potassium cardioplegia during cardiac ischemic arrest: a phosphorus 31 nuclear magnetic resonance study.

Cold K+ cardioplegia is commonly used to preserve the myocardium during surgical ischemia. Since the K+-induced membrane depolarization could cause a Ca2+-mediated breakdown of adenosine triphosphate, this study compared the influence of different electrolytes on high-energy phosphate metabolism during cardioplegic arrest phosphate metabolism during cardioplegic arrest and subsequent recovery of mechanical function. An isolated working heart was subjected to hypothermic ischemia for one hour. Metabolic studies were assessed on phosphorus 31 nuclear magnetic resonance (NMR). Results show that (1) K+ cardioplegia is harmful when the Ca2+ content is equal to 2 mEq/I; (2) deleterious effects of K+ are markedly reduced by lowering the Ca2+ content; (3) the most adequate preservation is provided by a Mg2+-rich-Ca2+-poor perfusate; (4) this protection is not enhanced by addition of K+. Finally, 31P NMR appears particularly appropriate for evaluating myocardial protection techniques since it allows noninvasive serial monitoring of high-energy phosphate content and subsequent correlation with functional recovery after ischemia.

Adenosine Triphosphate↗
PubMed1981

[Atrioventricular discordance. Results of a series of 34 operations].

From 1968 to 1980, 34 patients with atrioventricular discordance underwent intracardiac repair. Thirty three patients had a ventriculoarterial discordance (corrected transposition) and one patient had a double outlet right ventricle. The age at operation ranged from 12 months to 59 years (mean 19 years). The lesions were ventricular septal defect (26 cases), pulmonary stenosis (22 cases), atrioventricular valve anomalies (20 cases). Lesions were associated in 80% of the cases. Ventricular septal defect and pulmonary stenosis were combined in eleven patients. Seven patients had had palliative operations. Pulmonary stenosis was mostly of subvalvular type and treated with a conduit. A patient with double outlet right ventricle and pulmonary atresia had a conduit on the left pulmonary artery because the right one was non-functional. Ventricular septal defects were closed through the right A-V valve, and the stitches placed on the free edge of the defect. The tricuspid valve (systemic) was replaced in 10 cases. Hospital mortality was 38% but only 3 out of 14 (21,4%) patients operated upon since 1975 have died. Late mortality was 24% (5 patients) related to conduction problems in 3 patients. Three patients were reoperated with good results. Out of twelve patients with a long-term follow-up, eleven have a good functional result. 7 patients with preoperative A-V block and 3 patients with atrial fibrillation had pacemakers implanted. 16 patients had postoperative A-V block. The incidence of conduction problems is now reduced with the use of conduit for subvalvular pulmonary stenosis.

Adolescent↗
PubMed1980

[Congenital tricuspid insufficiency due to valvular dysplasia. Review of the literature in light of a case in a 40-year-old adult].

UNLABELLED: Congenital tricuspid incompetence due to valvular dysplasia is a defect involving the leaflets (normally inserted on the ring) the cordae tendinae and papillary muscles of the tricuspid valve. It is a rare condition, usually diagnosed at open heart. A case of congenital tricuspid incompetence in a 40 year old adult is reported. Surgery indicated for resistant heart failure, confirmed the preoperative clinical, echocardiographic and haemodynamic diagnosis. The dysplasia comprised absence of cordae and papillary muscles on two thirds of the anterior leaflet. Valvular replacement with a bioprosthesis was carried out. 31 other reported cases were discovered on review of the literature since 1923. Two main groups of patients were individualised according to their clinical contexts and outcome: --The first group comprises the newborn and infants. Cyanosis, cardiomegaly and right ventricular failure in the neonatal period raised the differential diagnosis of Ebstein's anomaly and Uhl's disease. The outcome was fatal in several days to weeks. Autopsy confirmed the diagnosis. --The second group comprises patients who decompensate during adult life with right ventricular failure and degrees of tricuspid incompetence. The natural outcome with or without medical treatment may be prolonged, one such patient dying at the age of 53. Congenital tricuspid incompetence, diagnosed after elimination of other causes, was confirmed at operation. Complementary investigations: --Cardiac catheterisation showed tricuspid incompetence and its haemodynamic effects. --Echocardiography, in our case, showed dilatation of the right ventricle and pulsed Doppler echocardiography suggested tricuspid incompetence. The inability to record the anterior tricuspid leaflet, an unusual feature considering the right ventricular dilatation, contrasted with perfect definition of the septal leaflet. The absence of echocardiography in the other 31 reported cases does not allow any conclusions to be drawn as to the significances of this sign. --The tricuspid valve dysplasia was precisely defined on pathological examination: a) thickened valve, b) hypoplastic chordae and papillary muscles, c) incomplete separation between the leaflets and ventricular wall, d) focal agenesis of valvular tissues. --An associated pulmonary artery stenosis in the newborn may explain the severity of symptoms in this age group. This hypothesis, based only on pathological studies, cannot be confirmed. TREATMENT: --In the newborn, the rare surgical attempts at repair have all failed. --In the adult, surgery, indicated for heart failure resistant to all medical treatment, is as for other organic tricuspid incompetence, annuloplasty or valve replacement, by mechanical or bioprosthesis. Porcine bioprosthesis, as chosen in the case reported, has been used by some authors for 5-8 years with good results. Nevertheless, the longer-term outcome of this type of prosthesis is not yet known.

Adolescent↗