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Biomedical subjects

M Morea

Publications and source records attributed to M Morea.

At least 55 records · Page 3Linked to original sources
PubMed1987

Long term results (15-30 years) of surgical repair of aortic coarctation.

The late outcome in 226 patients who survived surgical repair of aortic coarctation was assessed 15-30 years after operation. Twenty six patients died during the follow up mainly from causes related to surgical repair or to associated cardiovascular anomalies. The survival rates of patients operated on between the ages of four and 20 years are 97%, 97%, 92% at 10, 20, and 30 years after operation. For patients operated on after the age of 20 the corresponding rates are 93%, 85%, and 68%. This difference is statistically significant from the fifteenth year of follow up onwards. The survival of patients operated on before the age of 20 is not significantly different from that of a comparable general Italian population. Recoarctation occurred in only 8% of patients who had end to end anastomosis, whereas it occurred in 35% of those who had other types of operation. Two thirds of the patients were hypertensive at the last visit. The actuarial curve shows that blood pressure was normal in most patients 5-10 years after operation, but 30 years after coarctation repair only 32% of patients are expected to be normotensive. Thus early repair of aortic coarctation appears to improve long term survival. Intervention in older patients and when blood pressure is high seem to be the most important predictors of late hypertension.

Adolescent↗
PubMed1986

Myocardial protection by perioperative diltiazem drip: a clinical evaluation.

This study was undertaken to evaluate the potential role of a perioperative calcium-channel blocker (Diltiazem) infusion in improving myocardial preservation. Forty consecutive CAD patients were randomly assigned to a control (C; n = 20) and a treated (D; n = 20) group. In patients in the latter group diltiazem was continuously infused at 0.5 to 2.0 mcg/kg/min i.v. from anesthesia induction until the aortic cross-clamping, and from myocardial reperfusion till the 48th postoperative hour. During the preCPB phase hypertension occurred less frequently in group D (3 vs 12 cases, p = 0.0033). In the immediate postischemic period, depression of contractility and the need for inotropic support were observed in 3 cases in group D and in 9 in group C (p = 0.0384). Postoperatively, group D patients had a lower incidence rate of hyperkinetic arrhythmias or conduction disturbances (p = 0.0218), as well as of ECG signs of ischemia (p = 0.0016). Significant CK enzyme level increase was noted in 13 patients in group C versus 4 in group D (p = 0.0040). Two perioperative myocardial infarctions were diagnosed, both in group C. These clinical data show that continuous perioperative infusion of diltiazem can effectively increase myocardial preservation during ischemic arrest, without unfavorable effects on the hemodynamics, electrical activity or mechanical performance of the heart.

Benzazepines↗
PubMed1986

Carpentier-Edwards bioprosthesis: a 7-year follow-up in 361 patients.

Three hundred sixty-one patients undergoing heart valve replacement with Carpentier-Edwards bioprostheses (CE) were evaluated: 169 patients underwent replacement of the mitral valve (MVR), 124 of the aortic valve (AVR), one of the tricuspid valve (TVR) and 67 of 2 or more valves (mVR). A total of 420 CEs were implanted. Overall operative mortality was 4.7% (7.1 for MVR, 1.6 for AVR, 4.5 for mVR). Early complications included hemorrhage (5 cases), thromboembolism (one case), paraprosthetic leak (one case). Actuarial survival rates at 5 years were computed for overall deaths, cardiac deaths and prosthetic deaths. In the 3 subgroups these 3 rates were respectively 78.7 +/- 5.6%, 82.9 +/- 5.4%, 96.4 +/- 1.6% for MVR, 88.9 +/- 3.3%, 94.2 +/- 2.3%, 98.7 +/- 1.3% for AVR, and 82.3 +/- 5.9%, 88.3 +/- 5.1%, 98.5 +/- 1.5% for mVR. Actuarial freedom from prosthetic complications at 7 years was 59.6 +/- 7.5%, 78.1 +/- 4.1% and 61.9 +/- 8.0% for MVR, AVR and mVR patients. Thromboembolism-free rates were 87.2 +/- 3.9% and 99.2 +/- 0.8% for MVR and AVR, while the thromboembolic linearized rate was 2.8% per patient-year and instantaneous risk of thromboembolism was 4.1% at one and instantaneous risk of thromboembolism was 4.1% at one year for MVR. Anticoagulant-related hemorrhage linearized occurrence was 1.0%, 1.2% and 0.8% per patient-year among the 3 subgroups. Prosthetic endocarditis occurred in 12 patients with a linearized rate of 1.1% per patient-year. Eleven of these patients were treated successfully. Three episodes of primary tissue failure were recorded (0.2% linearized rate per year, instantaneous risk 3.5% at the sixth year).(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve↗
PubMed1986

Effect of platelet-activating factor (PAF) on human cardiac muscle.

The effect of platelet activating factor (PAF) on three mechanical [maximal mechanical tension (Pmax); time to peak tension; maximal rate of rise of tension (+dP/dt)] and four electrical [action potential duration (APD); resting membrane potential; overshoot; maximum rate of depolarization] parameters of cardiac function was studied on fragments of isolated human cardiac papillary muscle. 20 specimens of small tissue fragments excised from the left ventricle by open heart surgery were challenged with various doses of synthetic PAF (10(-10)-10(-6) M). PAF, but not its biologically inactive 2-lyso-derivative (lyso-PAF), induced a biphasic dose-dependent effect, characterized by a transient positive effect on inotropism (increased Pmax, +dP/dt) and of APD, followed by a marked, prolonged negative effect on both inotropism (decreased Pmax, time to peak tension, +dP/dt) and APD. No changes in resting membrane potential, overshoot and maximum rate of depolarization were detected after PAF challenge. Propranolol (2 X 10(-7) M) completely prevented the positive inotropic effect suggesting a stimulation of beta-receptors, possibly exerted by endogenous catecholamines. Indomethacin (1 X 10(-4) M) did not modify the initial positive effect, but markedly reduced the subsequent negative effect induced by PAF on inotropism. These findings are consistent with the interpretation that the effect of PAF on the inotropism is related to liberation of cyclooxygenase-derived metabolites.

Action Potentials↗
PubMed1986

Diltiazem cold cardioplegia in coronary artery surgery: effects on myocardial function and ischemia.

This study was undertaken to evaluate the myocardial preservation obtained by adding a calcium channel blocker, diltiazem (200 mcg/kg of body weight) to cold potassium cardioplegia in 24 patients with coronary artery disease who underwent myocardial revascularization, and were randomly divided into a treated Group D and a Control Group C. No significant differences were noted between the groups in cardiac electrical arrest and recovery time, recovery rhythm, mechanical function recovery, inotropic support, stroke index, or cardiac index. After cardiopulmonary bypass, the stroke index decreased by 13.1% in Group D and by 20.7% in Group C; cardiac index increased in both--18.6% and 14.0%, respectively--but the results were possibly from compensatory heart rate increases. Peripheral deltaP/deltat and endocardial viability ratios decreased in both groups. Coronary sinus enzymes and serum CK were slightly lower in the treated group. Serum CK-MB, however, was significantly higher in the Control Group. Electrocardiographic ischemic changes occurred in four patients, all in Group C (p =.046). Hyperkinetic arrhythmias occurred in five of the controls, but in none of the treated patients (p =.018). One perioperative myocardial infarction was diagnosed in the Control Group. These data suggest that diltiazem has no negative side effects on hemodynamics or cardiac rhythm and does not reduce impairment of myocardial function due to ischemia, but it does decrease the incidence of ischemic lesions in patients undergoing coronary artery bypass procedures.

Journal Article↗
PubMed1985

Porcine cardiac bioprostheses: evaluation of long-term results in 990 patients.

Clinical results with porcine bioprostheses were reviewed for 990 patients who underwent heart valve replacement from January, 1974, to December, 1980. Eight hundred and seventy-four Hancock, 283 Carpentier-Edwards, and 10 Liotta bioprostheses were used. In 23 patients, 26 mechanical prostheses were implanted as well. Overall operative mortality was 60 out of 990 (6.06%): 30 out of 506 (5.9%) for mitral valve replacement (MVR), 13 out of 287 (4.5%) for aortic valve replacement (AVR), 1 out of 4 (25%) for tricuspid valve replacement, 0 out of 2 for pulmonary valve replacement, and 16 out of 191 (8.4%) for multiple valve replacement. Cumulative follow-up covered 1,793 patient-years. (Actuarial survival at 7 years was 76.6 +/- 3% for MVR. At 6 years, it was 83.2 +/- 2.8% for AVR and 55 +/- 13.5% for multiple valve replacement.) Prosthesis-related survival at 7 years was 91.7 +/- 1.9% for MVR, and at 6 years, it was 96.6 +/- 1.5% for AVR and 95.1 +/- 2.2% for multiple valve replacement. Bioprosthesis survival, considering deaths or complications that led to reoperation as final events, was 84.2 +/- 3.7% at 7 years for mitral valves and 87.7 +/- 3.8% at 6 years for aortic valves. Emboli per 100 patient-years numbered 3.2 for MVR, 0.5 for AVR, and 1.6 for multiple valve replacement. Twenty-seven patients underwent reoperation, 12 for perivalvular leak, 5 for endocarditis, 6 for valve thrombosis, and 4 for primary tissue failure (linearized rates of 0.7, 0.3, 0.3, and 0.2% per patient-year, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1985

Postoperative histological diagnosis in two cases of unsuspected bioprosthetic endocarditis.

Two cases of preoperatively unsuspected porcine bioprosthetic endocarditis are presented. Both cases, thought to be a sterile thrombosis and a primary tissue failure respectively, were correctly diagnosed only with histological examination. Cultures and histological examination of the explanted tissue are necessary for a definite diagnosis in every case of prosthetic malfunction.

Adult↗
PubMed1984

Endocarditis in patients with bioprostheses: pathology and clinical correlations.

We studied 13 porcine bioprostheses removed from patients with endocarditis at our institute during the last 4.5 years. All bioprostheses had been removed at reoperation and were analyzed using anatomical and histological techniques. Each bioprosthesis was found to have developed rather constant lesions which were not related to the type of bioprosthesis. The stage of infection was not related to the duration of implantation. The presence of perivalvular abscesses was an ominous finding, often being the seat of persistent endocarditis. Our good clinical results of reoperation lead us to suggest that this be performed early once valvular or prosthetic malfunction is detected. Bioprostheses are, in our experience, the best choice in the surgical treatment of prosthetic valve endocarditis.

Adult↗
PubMed1984

Ascending aortic aneurysms: composite conduit replacement.

From July 1980 to February 1984, 26 patients underwent composite replacement of ascending aortic aneurysm and aortic valve with coronary reimplantation. This group included 14 patients with dissecting aneurysm (ten and four respectively, belonging to Types I and II), and 12 patients with chronic aneurysm (six atherosclerotic aneurysms, two Marfan's syndrome and four annuloaortic ectasia cases). Hospital mortality was 35.7% (5/14) in the dissection subgroups and 16.6% (2/12) in the chronic aneurysm subgroup (difference NS). No operative risk factor was recognized. The 19 survivors have been followed up for a total of 393 patient-months (range 5 to 49 months). Controls included echocardiography and computed tomography scanning. Two patients died because of rupture of a persistently dissected aorta; another patient died of an unknown cause. Total actuarial survival rate at 4 years was 58.3 +/- 10.4% (83.3 +/- 10.7% for chronic aneurysms and 42.3 +/- 13.4% for dissecting aneurysms). Among late survivors, there were no paravalvular leaks, new dissections, or thromboembolisms, although two perigraft hematomas and a persistent dissection were later disclosed. When appropriate, composite conduit replacement of the ascending aorta can increase the survival rate, and can also be useful in high-risk patients.

Journal Article↗
PubMed1979

Mutation generating a fragment of the major heat shock-inducible polypeptide in Drosophila melanogaster.

Drosophila melanogaster tissues carrying a third chromosome with the deletion Df(3R)Kar(D2) make a 40,000-dalton (Dal) heat shock protein not made by wild type. The unusual polypeptide was inducible in every tissue examined. Tryptic peptide fingerprints showed it to include part of the 70,000-Dal major heat shock protein. Mapping experiments placed the mutation responsible for the 40,000-Dal protein at or close to the kar(D2) deletion. One break point of the deletion is in subdivision 87A, close to or at a heat shock locus that codes for the 70,000-Dal protein. The results are consistent with the possibility that this break point is within a gene for the 70,000-Dal protein, leaving only the initial portion of its coding sequence. This would specify the direction of transcription of the mutant gene as proximal to distal on the normal chromosome. The 87A heat shock locus should contain at least two genes for the 70,000-Dal protein, because embryos homozygous for the kar(D2) deletion and lacking the heat shock locus at 87C, which also codes for the 70,000-Dal protein, nevertheless produced both the 40,000-Dal and the 70,000-Dal proteins upon temperature elevation. Using the presence of the 40,000-Dal protein to monitor chromosome segregation, we found that embryos homozygous for deletions of the heat shock puff site at 93D exhibited a normal electrophoretic pattern of heat shock proteins.

Animals↗
PubMed1979

[Myocardial protection from cardioplegic and hypothermia during aortic cross-clamping (author's ttrans)].

The clinical results with cardioplegic solutions and hypothermia during aortic cross-clamping are compared with the clinical results obtained with hypothermia only. To complete the study miocardial biopsies were obtained during aortic cross-clamping in order to evaluate the concentration of ATP and CPK. The obtained data confirm the effectiveness of the myocardial protection.

Adenosine Triphosphate↗
PubMed1977

Heart valve replacement with the Hancock bioprosthesis. Analysis of long-term results.

Between March 1970 and May 1976, 564 patients have undergone single or multiple heart valve replacement with the Hancock "SGP" bioprosthesis in our institution. Of these patients, 335 had single mitral, 102 aortic, one tricuspid, and 126 double or triple valve replacement, for a total of 629 xenografts. The long-term results, in terms of clinical improvement, survival, and complications, have been analyzed. Significant valve insufficiency secondary to primitive tissue alterations occurred in three patients, while reoperations were required in two for endocarditis and in two others for mitral stenosis caused by tissue ingrowth. We found that thromboembolic episodes occurred mainly in the early postoperative period up to the third month in 10 cases (1.76%). Three patients suffered peripheral embolization during the late follow-up period. Anticoagulants were not administered beyond 3 months postoperatively. Hemodynamic re-evaluation has been performed in 42 patients and the prosthesis has been shown to function properly either in the mitral or the aortic position. The data available to date indicate that the glutaraldehyde-preserved porcine valve is durable and we feel that its use is warranted in any valvular position.

Adolescent↗
PubMed1977

[The biological prostheses of Hancock in our experience of 250 subjects underwent a valvular replacement (author's transl)].

In this study we present the results of 5-years Follow-up of Clinical experimentation with biological prostheses of Hancock in 250 patients underwent a valvular replacement at the Cardiovascular Surgery Institute of Padua University in Verona. We report the immediate and long-term results with the death causes and the complications related above all with thrombo-embolic events. For such complications it was done a comparison relatively to the cases with mitral and aortic prostheses, with the results obtained from another Cardiovascular Surgery Center where are always applied artificial prostheses. From this comparison results that Hancock's biological prostheses has a major tendency to give incidence of embolic in the first months following the valvular replacement, but successively it is clearly to be prefered to artificial prostheses.

Evaluation Studies as Topic↗