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Biomedical subjects

C Antona

Publications and source records attributed to C Antona.

At least 55 records · Page 3Linked to original sources
PubMed1994

Reoperative cardiac valve surgery: a multivariable analysis of risk factors.

From December 1983 to March 1992, of 1650 patients who underwent a cardiac valve procedure 41 (2.5%) underwent reoperation on prosthetic heart valves. The indications for reoperation were: structural degeneration (13 patients, 32%), non-structural dysfunction (nine patients, 22%), prosthetic valve endocarditis (seven patients, 17%), valve thrombosis (four patients, 10%), native valve pathology (three patients, 7%), aortic ascending pathology (five patients, 12%). The hospital mortality rate for mitral valve reoperation was 12% (two of 17) and for reoperation on the aortic prosthesis 26% (five of 19). No deaths occurred for associated mitral and aortic replacement (zero of five). The mortality rate for associated procedures was 24% (four of 17) versus 12% (three of 24) for isolated procedures. Preoperative and operative variables were analysed to determine risk factors for hospital mortality. New York Heart Association functional class, ascites, endocarditis and surgical timing had a univariate influence on operative mortality. The pulmonary capillary wedge pressure and preoperative creatinine level were also higher in non-survivors. Elective reoperation had a mortality rate of 7%, while that for emergency procedures was 38%. Multivariable analysis indicated a longer extracorporeal circulation time and the urgent-emergency status as predictors of mortality. Reoperation before severe haemodynamic impairment occurs is recommended.

Aortic Valve↗
PubMed1993

Intracardiac ectopic thyroid: conservative surgical treatment.

The case of a patient with an intracardiac ectopic thyroid is reported. A cardiac tumor was found in a 66-year-old woman and was diagnosed by two-dimensional echocardiography. An intraoperative biopsy was performed, and the mass was recognized as an ectopic thyroid and treated with a conservative surgical approach because of the size, location, and relationship to adjacent structures. The 60-month follow-up shows normal echocardiographic images and the good clinical status of the patient.

Aged↗
PubMed1993

Straddling endoventricular pericardial patch in prevention of type I myocardial rupture.

Type I myocardial rupture due to atrioventricular discontinuity in the region of the posterior mitral annulus is a fearsome and nearly unpredictable complication of mitral valve replacement. We report a case of a 49-year-old patient who had been operated on for mitral valve replacement. The posterior mitral leaflet had heavy calcifications embedded through the annulus in the posterior ventricular wall. After removal of calcifications we avoided the risk of myocardial rupture by suturing a straddling pericardial patch on the atrioventricular junction. The operation resulted in complete recovery.

Heart Rupture↗
PubMed1993

Preoperative management and surgical therapy in complicated acute infective endocarditis: a 5-year experience.

Twenty-five patients underwent early and elective valve replacement for infective endocarditis during a 5-year period between April 1985 and March 1991. Indications for urgent surgical intervention performed at a mean 32 (range 6-47) days after admission were intractable heart failure, systemic emboli, septic multiorgan failure and the presence of vegetations. Indication for elective surgery was persistent (mean 42 (range 17-56) days) infection after appropriate antibiotic therapy. Twenty patients (80%) had a native valve endocarditis; five (20%) had prosthetic valve involvement. A total of 30 valvular prostheses were implanted: 22 (73.3%) were aortic (21 mechanical and one biological); eight (26.7%) were mitral (all mechanical). All unstable patients referred were treated before surgery in the intensive care unit and subjected to blood ultrafiltration to restore satisfactory circulatory parameters. No patient underwent cardiac catheterization; all patients were operated upon on the basis of echocardiographic data alone. One patient (4%) died during hospitalization; two (8%) died later at 48 and 12 months after the first intervention. The reoperation rate was 12%. After a mean follow-up of 49 (range 1-71) months, 21 of the survivors (95%) were in New York Heart Association functional class I or II; the actuarial 5-year survival rate was 87%. Precise preoperative assessment of early operative indications and timely association of medical therapy in unstable patients could represent a step forward in the treatment of acute infective endocarditis.

Adolescent↗
PubMed1992

[Reducing bleeding during extracorporeal circulation interventions by high doses of aprotinin].

The great risk of severe infectious diseases transmission through blood transfusion, has increased during the last years the effort to reduce the bank blood and its derivates use. Many techniques have proposed to achieve this purpose during and post cardiopulmonary bypass: normovolemic hemodilution, perioperative blood autotransfusion, postoperative return of extra corporeal circuit and chest drains blood and the particular use of some drugs. In the last few years several reports have been presented in the literature concerning the reduction of intra and postoperative bleeding in cardiac surgery by high dose Aprotinin administration. A randomized study with the use of this pharmacologic agent is presented: a group of patients was treated with Aprotinin (shared in two subgroups receiving respectively a different dose of the drug) and a control group. The results were highly encouraging both because of the reduction of peri and postoperative bleeding and because of the bank blood use important reduction.

Adult↗
PubMed1992

[The use of the inferior epigastric artery as alternative conduit for myocardial revascularization: our experience].

When complete revascularization can not be obtained with the internal mammary artery and saphenous veins, the inferior epigastric artery may be an excellent alternative conduit. We describe our experience with this conduit, review the anatomy of this artery, and present the evolution of our harvesting technique through a pararettal approach. Proximal anastomoses were made first with the aid of an oval cuff of the common femoral artery (5 cases, Group A). Two patients (40%) of this group studied postoperatively revealed a graft occlusion. In the last 13 cases (Group B) we tailored the proximal anastomoses directly to the aorta. All patients studied postoperatively showed patent inferior epigastric artery grafts. There were no hernias and no deaths. Inferior epigastric artery can be considered a good alternative conduit in myocardial revascularization.

Abdominal Muscles↗
PubMed1991

Alpha 1 adrenoceptor subtype mediates noradrenaline induced contraction of the human internal mammary artery: radioligand and functional studies.

STUDY OBJECTIVE: The aim was to evaluate the characteristics of alpha adrenergic binding sites on human internal mammary arteries and the alpha adrenoceptor mediated vasoconstrictor response to catecholamines. DESIGN: Human internal mammary arteries were cut longitudinally, the intimal layer was scraped, and the arteries homogenised and centrifuged at 50,000 g to obtain a membrane pellet. Saturation isotherms with [3H]-prazosin were done with 50-100 micrograms plasma membranes per tube and increasing concentrations of [3H]-prazosin (non-specific binding: 2.5 mM noradrenaline plus superoxide dismutase and catalase). Kinetic isotherms were done with 100 micrograms plasma membranes and 1-5 nM [3H]-prazosin for time periods ranging from 1 to 90 min; at the equilibrium, dissociation of [3H]-prazosin was achieved by 10 microM prazosin. alpha 2 Adrenoceptor density on internal mammary artery membranes was assessed with [3H]-rauwolscine (non-specific binding: 1 microM yohimbine). Separation of membrane bound radioactivity was achieved by rapid vacuum filtration through Whatman GF/C fibre filters. Saturation isotherms were evaluated by Scatchard plots and kinetic data, and competition isotherms by Enzfitter analysis. Contractility studies were done with helical strips of artery (without adventitial layer) placed in a thermostated perfusion bath. Data were obtained in the presence of different concentrations of agonists and antagonist to obtain Schild plots. Antagonist drugs were employed at only one concentration for each preparation. SUBJECTS: Mammary arteries were collected from 51 patients (age range 42-65 years) undergoing surgery for coronary grafting. MEASUREMENTS AND MAIN RESULTS: The binding of [3H]-prazosin to arterial plasma membrane was rapid and reversible. The K + 1 was 0.13 (SD 0.03) X 10(9) M.min-1 (n = 5) and the Kd, determined as a ratio between k-1/K + 1, was 0.34(0.01) nM (n = 5). [3H]-Prazosin binding, displaceable by 2.5 mM (-)-noradrenaline, was saturable and disclosed an alpha 1 adrenoceptor density of 30(3) fmol.mg-1 protein with a dissociation constant (Kd) of 215(50) pM (n = 18). The adrenergic agonists competed with [3H]-prazosin in the following order of potency: (-)-adrenaline [Ki = 0.6(0.1) microM; n = 5] greater than (-)-noradrenaline [Ki = 1.05(0.015) microM; n = 12] much greater than (-)-isoprenaline [Ki = 150(10) microM; n = 4]. Specific binding of [3H]-rauwolscine to IMA plasma membranes was negligible (about 2 fmol.mg-1 protein) (n = 15) with an unfavourable ratio of non-specific v specific binding. Catecholamines induced a dose dependent contractile response in arterial strips; (-)-noradrenaline: EC50 = 0.48(0.12) microM, n = 20; (-)-adrenaline: EC50 = 0.15(0.16) microM, n = 10; and methoxamine, a selective alpha 1 adrenergic agonist: EC50 0.67(0.15) microM, n = 10. The alpha 2 adrenoceptor agonists BHT-933, BHT-920, and guanabenz did not contract the arterial strips (up to 10 mM). Prazosin (0.03-0.1 microM) produced concentration dependent right shifts of the (-)-noradrenaline [pA2 = 9.83(0.11), n = 19], (-)-adrenaline [pA2 = 9.50(0.31), n = 10], and methoxamine [pA2 = 8.96(0.18), n = 10] concentration-response curve. CONCLUSIONS - Internal mammary artery plasma membranes possess alpha 1 adrenoceptors which are involved in the vasoconstrictor response to catecholamines. alpha 2 Adrenoceptors seem not to be involved.

Adult↗
PubMed1990

Role of 5-HT2 receptors in serotonin-induced contraction in the human mammary artery.

We studied the effects of serotonin (5-HT) on isolated human mammary arteries obtained from patients undergoing coronary by-pass grafting. 5-HT induced a concentration-dependent contractile response in the mammary artery, with an EC50 value of 0.34 microM. The 5-HT2 antagonist, ketanserin, reversed the contractions evoked by 5-HT in a competitive manner at a low concentration (10(-8) M), whereas non-competitive antagonism was apparent at higher concentrations (5 X 10(-8)-5 X 10(-7) M). To investigate whether the alpha 1-blocking component of ketanserin plays a role in the response observed in this vessel, we evaluated the effect of ketanserin on contractions induced by (-)-norepinephrine. Ketanserin, in concentrations up to 10(-7) M, did not influence the norepinephrine-induced contractions. Moreover, a threshold concentration of 5-HT (10(-7) M) amplified the contractile effect induced by norepinephrine (5 X 10(-8) M), and this response was inhibited by ketanserin (10(-7) M). The selective 5-HT3 antagonist, GR 38032F, did not affect the 5-HT-induced contractions. These findings indicate that the human mammary artery is a vascular tissue sensitive to 5-HT. The 5-HT2 receptor subtype appears to mediate the response.

Female↗
PubMed1990

5-Hydroxytryptamine induces contraction in isolated human mammary artery: effect of ketanserin.

5-hydroxytryptamine (5HT) treatment produced dose-related contractions in the human internal mammary artery with an EC50 value of 3.4 X 10(-7) M. The 5HT2 receptor antagonist ketanserin reversed the contractions evoked by 5HT in a competitive manner at a low concentration (10(-8) M), whereas a noncompetitive antagonism was apparent at higher concentrations (5 X 10(-8) M to 5 X 10(-7) M). The alpha 1-blocking component of ketanserin was evaluated by studying the effect of ketanserin upon the contractile response evoked by norepinephrine. Up to 10(-7) M, ketanserin did not influence norepinephrine-induced contractions. These findings indicate that the mammary artery is a vascular tissue sensitive to contractions induced by 5HT and that the drug ketanserin antagonizes this contractile response through the 5HT2 receptor subtype.

Female↗
PubMed1989

[Positive alveolar pressure reduces bronchial systemic-to-pulmonary blood flow in man].

We studied in humans during total cardio-pulmonary by-pass the effects of positive alveolar pressure on systemic to pulmonary bronchial blood flow. Systemic to pulmonary bronchial blood flow is the entire bronchial blood flow to the lung and was measured as the volume of blood which accumulates in the left heart when there is no pulmonary flow. Systemic to pulmonary bronchial blood flow was vented by gravity via a cannula (18 French) introduced in the upper superior pulmonary vein and advanced into the lower most portion of the left heart. In Group A (10 patients) systemic to pulmonary bronchial blood flow was measured with alveolar pressure constant at 4.0 +/- 0.4 cm H2O for 53.5 +/- 6.2 min (range 25 to 95 min), and ranged between 0.32 and 2.76% of cardiac output (pump flow) remaining constant with time. In Group B (10 patients) systemic to pulmonary bronchial blood flow was measured for 2 periods of 20 min each with alveolar pressure equal 4.1 +/- 0.2 and 14.1 +/- 0.4 cm H2O respectively. The increase of alveolar pressure reduced systemic to pulmonary bronchial blood flow by almost 40%. The reduction of systemic to pulmonary bronchial blood flow we observed may be deleterious for the survival of the lung parenchyma particularly in some circumstances. This is the case of pulmonary embolism, when bronchial blood flow is the major source of blood to the lung parenchyma and serves to prevent pulmonary infarction, or the case of acute respiratory distress syndrome, when pulmonary flow is compromised and systemic to pulmonary bronchial blood flow increases.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1988

Aneurysms of the coronary arteries: one case report.

True aneurysms of the coronary arteries are very uncommon. In our institution, from December 1982 to April 1987, in more than 2500 coronarographies, we observed only one case whose angiographic findings revealed a real fusiform aneurysm (at least 3 times the diameter of the original vessel) of the right coronary artery. The same patient exhibited a left anterior descending artery ectasia too, as we already noted in other cases not included in the present report. The other coronary arteries showed no associated lesions. Clinical findings included a previous myocardial inferior infarction and typical precordial effort pain with a basal and stress ECG showing non specific ST-T wave abnormalities. The patient underwent right coronary endoaneurysmectomy with interposition of a saphenous vein graft. Postoperative course was uneventful and 8 months after surgery the patient was asymptomatic, and basal and effort ECG showed no ischemic modification. Control angiogram revealed an optimal anatomical reconstruction with no further evolution of the left anterior descending artery dilatation. The distinction between vessel dilation and an aneurysm is discussed.

Adult↗
PubMed1988

Blood-transmitted and clotting-factor-transmitted non-A, non-B hepatitis. Clinical differences and evolution.

In a prospective study of post-transfusion hepatitis (PTH) in open-heart surgery patients, non-A, non-B hepatitis was diagnosed by exclusion criteria in 100 patients (14.1%). The frequency of hepatitis was significantly higher (56.9%; p less than 0.001) in patients receiving blood units and clotting-factor concentrates of commercial origin, which were administered for the occurrence of bleeding complications during surgery, as compared to patients treated with blood units alone (10.3%). When clinical features of hepatitis at presentation were compared in the two groups of patients, a shorter incubation period (p less than 0.05) and a higher prevalence of jaundice (p less than 0.01) were found in patients receiving blood and clotting-factors. Persistence of abnormal alanine aminotransferase (ALT) levels after 12 months from onset were found in more than 70% of patients in both groups. Late biochemical remission, however, was observed in 21% of patients receiving blood units alone, but in none of those who received clotting factors. All these latter patients had histologic features of active liver disease during the chronic phase of the illness, as compared to only 46% of patients receiving blood units alone (p = 0.02). Our results show significant differences in the clinical course of non-A, non-B hepatitis transmitted by blood as compared to clotting factors, supporting the hypothesis of different etiological non-A, non-B agents.

Adult↗