Search PubMed⌕ Search

Biomedical subjects

M Turina

Publications and source records attributed to M Turina.

At least 127 records · Page 7Linked to original sources
PubMed1996

[Thrombosis-resistant heparin-coated diffusion membrane oxygenators: an experimental study].

In the present study the thromboresistance of heparin-coated diffusion membrane oxygenators (Jostra, M 30) combined with heparin-coated venous reservoirs, tubing sets and arterial filters was investigated in six bovine experiments (70 +/- 5 kg). The perfusion with reduced systemic heparin dose (100 IE/kg) body weight) was performed with activated clotting time over 180 seconds. The perfusion began with a blood flow of 31/min and was maintained during six hours. Clotting studies including blood platelet count, activated clotting time, fibrinogen (factor I), antithrombin III and fibrinopeptid A were performed before the operation and ten minutes, two hours and five and six hours after beginning of bypass. The venous and arterial saturation remained stable during the whole investigation. After ten minutes activated clotting time dropped from 619 +/- 114s to 203 +/- 15s after six hours (p < 0.05). The antithrombin III level changed significantly from 109 +/- 11% to 95 +/- 16%. Factor 1 and fibrinopeptid A changes were not significant: from 1.6 +/- 0.3 g/1 to 1.5 +/- 0.3 g/1, and 3.0 +/- 1.4 ng/mL to 3.5 +/- 1.2 ng/mL, accordingly. There were no mechanical defects and especially no plasma leakage. Slight sediments were found only in areas of stagnant blood flow. The investigated bypass circuit with reduced systemic heparinization seems therefore particularly appropriate for long-term perfusions.

Animals↗
PubMed1996

[Self-expanding endoluminal vascular prosthesis: experimental basis and in-vivo evaluation].

The present study investigates the physical properties and the in vivo application of in vivo of a self-expandable stent (Wallstent) with an incorporated sealant of microporous polyurethane. Measurements of diameter and length as a function axial load featured the data for the calculation for radial pressure. Porosity control was assessed in comparison to non gelatin-sealed knitted Dacron. 11 stents on a 11.5F catheter were inserted in the aorta of three minipigs and evaluated by pressure measurement and angiography. The coverage of the stent causes an increase of 0.05-0.1 bar of radial pressure. The graph received by calculations demonstrates the corresponding pressure for every given diameter of the stents. Porosity is similar to the Dacron graft. The patency-rate is 100%. Characteristics of this covered stents meet requirements of an endovascular prostheses. Exclusion of fistulas and small aneurysms seems to be possible.

Animals↗
PubMed1996

[Incidence, clinical aspects and therapy of late pericardial tamponade following heart surgery].

Late cardiac tamponade is a very severe condition that presents with subtle signs and symptoms within days or weeks after cardiac surgery. In a consecutive series of 3782 patients, 33 developed this complication, mostly due to overdosage of anticoagulants or to unsafe combination of 2 anticoagulation regimen. Diagnosis can be difficult and is best confirmed by echocardiography; in patients with primary uneventful recovery and sudden cardiocirculatory deterioration, intensive work-up should be performed to exclude or confirm the suspicion of late pericardial tamponade. The treatment of late pericardial tamponade should not be delayed and consists in subxyphoidal drainage. Re-sternotomy might be necessary to assume complete decompression of the heart in case of well-localized and posterior tamponade and/or organized pericardial fluid. Since this complication can happen in any patient transferred to peripheral hospital for postoperative recovery after cardiac surgery, we believe that this complication should be recognized very early and should be treated, in case of necessity, by general surgeons. Usually, no active bleeding is found at revision.

Adult↗
PubMed1996

[Latex covering and mechanical analysis of balloon expandable stents].

To the moment a few stents of metallic coils or meshes are available with a sealing coverage. In the present study balloon-expandable stents have been covered with a thin layer of natural rubber latex. The physical properties of these impervious stents were compared to the conventional stents. The expansion, the loss of expansion and the deformity during and after balloon inflation have been analyzed. In the pressure zone of 4-6 bar the mechanical characteristics of the impervious stents were similar to the conventional stents. The stents were expanded at 100% related on the balloon diameter used for expansion. Additional pressure of 1 bar was necessary to expand the impervious stents. At balloon pressure below 4 bar the stents tied the balloons in the midzone. The impervious stents, expanded at 6, 8 and 10mm, underwent a loss of expansion of 10% after withdrawal of the balloons. Their configuration was barrel-shaped (4% central enlargement) due to the latex rubber, constricting the wire meshes at both ends. These preliminary results are encouraging and allow further investigations.

Biomechanical Phenomena↗
PubMed1996

Low-dose cyclosporine treatment fails to prevent coronary luminal narrowing after heart transplantation.

BACKGROUND: Cyclosporine has been reported to induce endothelial dysfunction, arterial vasculitis, and accelerated atherosclerosis in experimental models. The purpose of the present study was to evaluate whether low-dose cyclosporine treatment started 1 year after heart transplantation reduces graft coronary artery narrowing compared with conventional cyclosporine doses. METHODS: One year after heart transplantation, 30 patients were randomly assigned to receive low-dose cyclosporine A (whole-blood polyclonal cyclosporine target trough levels 200 to 400 micrograms/L; group A; n = 15) or usual cyclosporine dosage (target levels 400 to 600 micrograms/L; group B; n = 15). Proximal and distal diameters of the left anterior descending, circumflex, and right coronary arteries were measured by quantitative coronary angiography at baseline (1 year after transplantation) and at 2 and 3 years after transplantation. RESULTS: One major cardiac event occurred in group A (retransplantation) and two in group B (sudden deaths). Moderate to severe allograft rejection (International Society for Heart and Lung Transplantation score 3A or higher) occurred in seven patients in group A and five in group B during the study period. Mean biopsy sample rejection score during the same period was increased in group A compared with that in group B (1.44 +/- 0.63 versus 1.05 +/- 0.59; p < 0.05). New angiographic evidence of vascular disease was observed in four patients of group A and in one patient of group B. Proximal coronary artery diameter was slightly, although not significantly, reduced in both groups at follow-up angiography. Distal segments showed a significant diameter reduction, which was greater in group A than in group B (-9.7% +/- 1.1% and -5.2% +/- 1.3%, respectively; p < 0.05). CONCLUSIONS: Cyclosporine dose reduction started 1 year after heart transplantation is ineffective in reducing coronary luminal narrowing and may be associated with an increased prevalence of cardiac allograft vasculopathy, especially in the distal coronary tree. Low-dose cyclosporine treatment may slightly enhance the risk of allograft rejection. Further investigations are needed to evaluate the effects of cyclosporine dose reduction started at an earlier time after heart transplantation.

Adult↗
PubMed1996

[Morphology of abdominal aortic aneurysms with reference to endovascular blood vessel prosthesis].

The purpose of this report was to describe the frequency and morphology of infrarenal aortic aneurysms suitable for endovascular tube graft repair. Preoperative abdominal CT scans of 89 patients undergoing open tube graft repair were analyzed retrospectively by measurements of lengths and diameters of the aneurysms. The cases were divided into 3 separate groups: most suitable aneurysms with neck and cuff in 10% (9/89), aneurysms (59%, 52/89) with either a neck (92%) or a cuff (8%), and finally aneurysms without a neck or a cuff (31%, 28/89). The anatomically suitable aneurysms have a neck of 31 +/- 19 mm in length and 23 +/- 4 mm in diameter, a cuff of 17 +/- 6 mm in length and 25 +/- 6 mm in diameter. The aneurysms have a nearly saccular nature with a "saccular index" of 0.81 +/- 0.17, p = 0.009. It appears that 10% of aneurysms restricted to the infrarenal aortic segment fulfill all criterias for endovascular straight tube graft repair.

Aged↗
PubMed1995

Seeding with omental cells prevents late neointimal hyperplasia in small-diameter Dacron grafts.

BACKGROUND: The influence of complete endothelialization of a prosthetic graft on development of late neointimal hyperplasia is unknown. This study was designed to investigate the effect of complete coverage with endothelial-like cells on late neointimal hyperplasia in small-diameter Dacron grafts seeded with omental cells in a canine model. METHODS AND RESULTS: Four-mm-ID Dacron grafts were seeded with cells from omentum and implanted in the carotid arteries in 24 mongrel dogs. Each dog received one seeded and one nonseeded graft. The graft patencies were assessed by angiography at 1, 5, 12, 26, and 52 weeks after surgery. The prostheses were explanted at 5, 12, 26, and 52 weeks after surgery and underwent microscopic studies. The actuarial patency rates at 1, 5, 12, 26, and 52 weeks were 100%, 95%, 95%, 95% and 95% for seeded grafts and 100%, 86%, 49%, 40%, and 13% for nonseeded grafts, respectively. The seeded grafts exhibited a uniform endothelial-like luminal monolayer without the development of late neointimal proliferation or anastomotic neointimal hyperplasia. Neointimal tissue thickness increased up to 6 months; no additional progression of the subendothelial tissue thickness was observed, in fact there was an insignificant decrease. CONCLUSIONS: Seeding with omental cells prevents development of late neointimal hyperplasia of small diameter prosthetic vascular grafts in a canine model.

Animals↗
PubMed1995

[Retrospective analysis of early and late results following surgical intervention in supraventricular arrhythmia].

The results of surgical procedures for treatment of supraventricular tachycardias were assessed in 65 patients undergoing operation between January, 1980 and December, 1993. Indications for intervention were WPW (59 patients), atrial fibrillation (5 patients) and atrial flutter (1 patient). All cases of WPW were refractory to medical treatment and 14 of 58 patients had one or several syncopes, 4 of whom had to be resuscitated. The surgical treatment of these patients was dissection of an accessory atrioventricular pathway. 15 of these patients underwent heart operation for a different indication at the same time. A total of 60 accessory pathways were diagnosed preoperatively, while 4 were located intraoperatively. The reoperation rate was 3% (2 patients) due to persistent WPW. Incidence of total AV block after the operation was 7% (4 patients). In the late postoperative stage, 12 patients developed supraventricular tachycardias, but none of these cases required surgical treatment. The actuarial survival rate after 10 years was 100%, and after 14 years 96%. We conclude that surgical dissection of accessory pathways offers a good alternative in cases of unsuccessful catheter ablative procedures or in cases of concomitant heart surgery. In 6 patients with mitral valve surgery, associated chronic atrial fibrillation was found. A concomitant Maze-procedure was performed for the purpose of surgically converting the atrial fibrillation to a stable sinus rhythm. The early postoperative results are promising.

Adolescent↗
PubMed1995

Normalization of diastolic dysfunction in aortic stenosis late after valve replacement.

BACKGROUND: The remodeling of the left ventricle in patients with aortic stenosis after aortic valve replacement (AVR) is a complex process involving structural and functional changes. METHODS AND RESULTS: Twenty-two patients were included in the present analysis. Twelve patients with severe aortic stenosis were studied before surgery, early (22 +/- 8 months) and late (81 +/- 22 months) after AVR using left ventricular biplane angiograms, high-fidelity pressure measurements, and endomyocardial biopsies. Ten healthy subjects were used as controls. Left ventricular systolic function was assessed from biplane ejection fraction; and diastolic function from the time constant of relaxation, the peak filling rate, and the myocardial stiffness constant. Left ventricular structure was evaluated from interstitial fibrosis, fibrous content, and muscle fiber diameter. Left ventricular muscle mass was significantly increased before surgery in patients with aortic stenosis and remained increased early after surgery, although there was a 35% decrease. Late after AVR, muscle mass decreased significantly but remained slightly (P = NS) elevated. Left ventricular ejection fraction increased slightly after AVR. Left ventricular relaxation was significantly prolonged before surgery and returned toward normal early and late after AVR. Peak filling rates remained unchanged before and after surgery. Myocardial stiffness constant was increased before surgery in patients with aortic stenosis compared with controls and increased even further early after AVR but was normalized late after surgery. Muscle fiber diameter was elevated in patients with aortic stenosis before and after surgery compared with controls; however, it decreased significantly early and late after AVR with respect to preoperative data but remained hypertrophied even late after surgery. Interstitial fibrosis and fibrous contents were larger before surgery than in control subjects and increased even more early but decreased significantly late after AVR. CONCLUSIONS: Diastolic stiffness increases in aortic stenosis early after AVR parallel to the increase in interstitial fibrosis, whereas relaxation rate decreases with a reduction in left ventricular muscle mass. Late after AVR, both diastolic stiffness and relaxation are normalized due to the regression of both muscular and nonmuscular tissue. Thus, reversal of diastolic dysfunction in aortic stenosis takes years and is accompanied by a slow regression of interstitial fibrosis.

Adult↗
PubMed1995

[Early and late results of the surgical treatment of left ventricular aneurysms; report of 105 patients].

This study determined perioperative mortality and morbidity and attempted to identify predictors of operative mortality and long-term outcome in a series of 105 patients who underwent surgery for left ventricular aneurysm at this institution during a 7-year period. The main indications for treatment of ventricular aneurysm were angina, dyspnea, ventricular arrhythmias and systemic embolism. Overall mortality was 5.7% and 5-year survival 78%. Left ventricular systolic function, age, unstable angina and previous cardiac surgery were independent predictors of operative mortality and of long-term survival. Main complications observed were perioperative myocardial infarction, ventricular tachyarrhythmias and neurological, almost reversible defects. Although our experience with newer techniques such as patch plasty has been acquired in recent years, according to the literature the type of aneurysm repair seems not to be a strong predicator of operative mortality or improved long-term survival. Echocardiography provides important information concerning the extent of tissue resection needed and the ideal size of the patch. In patients with symptomatic coronary disease, complete revascularization should be attempted to allow recovery of adjacent myocardium after restoration of ventricular geometry. Repair of left ventricular aneurysm can be performed with acceptably low mortality by linear closure or by patch plasty technique. Remodelling the left ventricle using an endocardial patch has been found to fulfill its theoretical advantages in improving ventricular performance, by restoring the functional geometry of the heart. This operation can be performed with low perioperative risk and leads to a late functional improvement in the majority of patients.

Aged↗
PubMed1995

[Surgical therapy in unstable angina pectoris].

In order to assess the value of surgical revascularization of coronary arteries in patients with unstable angina pectoris, a series of 551/3397 consecutive patients belonging to New York Heart Association (NYHA) class IV was investigated. Fulfillment of at least two of the following criteria is mandatory for diagnosis unstable angina pectoris: slightly increased CK (< 300 IU/l), modified ECG at rest (decreased ST-T, increased ST), therapy-resistant post-infarction angina, therapy-resistant angina at rest, increased severity, duration or frequency of angina attacks within the last three months, insufficient therapeutic response. Patients with acute myocardial infarction were excluded from analysis. 362/551 patients out of the investigated cohort fulfilled criteria of unstable angina pectoris NYHA class IV; in 189/551 patients, criteria of stable angina pectoris NYHA class IV were fulfilled (controls). The mean follow-up period for these patients was 72 +/- 33 months (24 +/- 144 months). There were no differences regarding age, percentage of patients with three vessel disease, ejection fraction of the left ventricle and of cardiogenic shock. The mean number of aortocoronary grafts was 3.8 +/- 1.3 in patients with unstable angina, compared to 3.4 +/- 1.5 in patients with stable angina pectoris (p < 0.05). An intra-aortic balloon pump had to be applied in 8% of patients with unstable angina compared to 3% in stable angina. A mortality of 2% within 30 days of surgery was registered in unstable compared to 3% in stable angina pectoris (n.s).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

[Surgery of the abdominal aorta in the geriatric population: characteristics and results].

Refinement in surgical technique and perioperative management have considerably improved morbidity and mortality rates of carotid endarterectomy and abdominal aortic surgery, thus allowing a more aggressive approach in the treatment of carotid stenosis, abdominal aortic aneurysm and aorto-iliac occlusive disease in the elderly population (> 70 years). We review our experience with 446 consecutive patients undergoing surgery of the abdominal aorta: 295 patients (mean age 75.5 years) underwent resection of an abdominal aortic aneurysm (asymptomatic but > 5-6 cm, (n = 193), symptomatic (n = 67) or ruptured (n = 35). Additionally, 198 patients were treated surgically for aorto-iliac occlusive disease. A small group of 13 patients was deferred for combined operation, including prior myocardial revascularization and subsequent vascular surgery during the same anesthesia. The majority of patients had several cardiovascular risk factors and/or significant associated diseases. Mortality (< 30 days) was 3.5% following aorto-iliac bypass in the treatment of arterial occlusive disease and 8.4% after aneurysm repair (asymptomatic, symptomatic and ruptured aneurysms all included). 5-year survival was 74% and 64% after repair of aortic aneurysm and treatment of aorto-iliac occlusive disease respectively. On the basis of these results, we believe that major vascular surgery is still justified in elderly patients and can be achieved with reasonable mortality and morbidity. Main goals of the surgery, e.g. to relieve suffering, restore function so as to limit disability and dependency, and prolongation of life expectancy in a dignified and meaningful life-style, are realized the majority of operative survivors.

Aged↗
PubMed1995

[Interrupted aortic arch: fortuitous diagnosis in a 72-year-old female patient with severe aortic insufficiency].

Interrupted aortic arch, defined as complete luminal and anatomic discontinuity between ascending and descending aorta, is an uncommon and highly lethal anomaly. We report the case of a 72-year-old woman scheduled for aortic valve replacement because of severe regurgitation. During preoperative catheterization, it was not possible to reach the ascending aorta from a femoral puncture. Further radiological investigation demonstrated interrupted aortic arch of type A without other cardiac or vascular anomalies. Postoperative course after aortic valve replacement and ascending-to-supraceliac aortic bypass was initially uneventful. Unfortunately, pericardial tamponade developed 10 days after the operation and required re-exploration, during which no active bleeding could be found. Recurrent effusion occurred and the patient finally died from severe shock and multiorgan failure. This exceptional case prompted a review of the literature which confirmed the rarity of this presentation in adult patients. It seems interesting that only mild arterial hypertension of the upper extremities was retrospectively found in this patient.

Aged↗
PubMed1995

Left ventricular function in chronic mitral regurgitation: preoperative and postoperative comparison.

OBJECTIVES: The present study was designed to evaluate the effects of surgical procedure on left ventricular systolic and diastolic function in patients with mitral regurgitation. BACKGROUND: Left ventricular systolic function has been shown to decline after operation in patients with chronic mitral regurgitation. METHODS: Using simultaneous cineangiography and left ventricular micromanometry, we evaluated left ventricular systolic and diastolic function in 14 patients with chronic mitral regurgitation both preoperatively and at an average of 22 months after operation. Eight patients underwent mitral valve reconstruction, and six had a valve replacement with interruption of the chordae tendineae. We compared these patients with 10 control subjects. RESULTS: Preoperatively, patients with mitral regurgitation demonstrated normal global and regional left ventricular systolic function. Peak rate of diastolic filling was increased (p < 0.01), and passive chamber stiffness was decreased, compared with that in control subjects (p < 0.01), and there was normal myocardial stiffness. Postoperatively, systolic and diastolic function returned to normal in patients undergoing mitral valve reconstruction. In contrast, global systolic function was depressed in patients after valve replacement (p < 0.05), with regional dysfunction in the area of papillary muscle attachment (p < 0.01). Diastolic function was depressed in this group, with a prolonged time constant of pressure decay (p < 0.01) and a depressed rate of early diastolic filling and strain rate (p < 0.05). Passive elastic stiffness was within the normal range in all postoperative patients. CONCLUSIONS: The type of operation performed to correct chronic mitral regurgitation has an important effect on postoperative left ventricular function. Systolic and diastolic function are preserved after mitral valve reconstruction. Mitral valve replacement with chordal interruption is associated with global and regional systolic dysfunction and early diastolic filling and relaxation abnormalities.

Adult↗
PubMed1995

The influence of leukocyte filtration during cardiopulmonary bypass on postoperative lung function. A clinical study.

The accumulation of activated leukocytes in the pulmonary circulation plays an important role in the pathogenesis of lung dysfunction associated with cardiopulmonary bypass. Animal studies have demonstrated that the elimination of leukocytes from the circulation reduces postoperative lung injury and improves postoperative pulmonary function. We conducted a prospective randomized clinical study to evaluate whether postoperative lung function could be improved by use of a leukocyte filter during cardiopulmonary bypass. Elective coronary artery bypass grafting was done with a leukocyte-depleting arterial blood filter incorporated in the extracorporeal circuit (14 patients, leukocyte filter group) or without the filter (18 patients, control group). Blood samples collected at intervals before, during, and after operation were used for analysis of blood cell counts, elastase concentrations, and arterial blood gases. The use of the leukocyte filter caused no significant reduction in leukocyte count (p = 0.86). There were no differences in postoperative lung function between the groups, as assessed through (1) oxygenation index (290 for leukocyte filter group compared with 329 for control group, 95% confidence interval, 286 to 372, p = 0.21), (2) pulmonary vascular resistance (p = 0.10), and (3) intubation time (16.6 hours for leukocyte filter group versus 15.7 hours for control group, 95% confidence interval, 12.1 to 19.1 hours, p = 0.72). The levels of neutrophil elastase were significantly higher at the end of cardiopulmonary bypass in the leukocyte filter group (460 microgram/L in leukocyte filter group versus 230 microgram/L in control group, 95% confidence interval, 101 to 359 microgram/L, p = 0.003). We conclude that the clinical use of the present form of leukocyte-depleting filter did not improve any of the postoperative lung function parameters analyzed in this study.

Cardiopulmonary Bypass↗