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Biomedical subjects

M Turina

Publications and source records attributed to M Turina.

At least 91 records · Page 5Linked to original sources
PubMed1998

Determinants of left ventricular diastolic function during myocardial ischemia: influence of myocardial structure and pericardial constraint.

OBJECTIVE: To assess the influence of myocardial structure and pericardial constraint during exercise ischemia on regional left ventricular passive elastic properties. METHODS: Left ventricular regional function was assessed at rest and during exercise using biplane angiography and high-fidelity pressure measurements. Twenty patients with either normal (n = 7) or stenotic coronary arteries (n = 13) were studied before and after successful bypass surgery. At the time of surgery, left ventricular transmural biopsies were taken from a normally perfused and a hypoperfused left ventricular region. RESULTS: Regional stiffness increased in the ischemic zone during exercise, but remained unchanged after revascularization. Regional fibrosis was significantly enhanced in the ischemic region compared with that in the normally perfused zone. No correlation was found between structural data and regional passive elastic properties, but there was a significant correlation between right atrial pressure and the asymptote of the diastolic pressure--volume relationship. CONCLUSIONS: Acute regional diastolic dysfunction can be observed during exercise in patients with coronary artery disease. Structural changes seem to have a minor role in the occurrence of diastolic dysfunction in the absence of myocardial infarction. The observed upward shift of the pressure-volume relationship during ischemia can be attributed to pericardial constraint that is manifested by an increase in right arterial pressure.

Angiocardiography↗
PubMed1998

Long-term follow up of patients with endomyocardial fibrosis: effects of surgery.

AIMS: To determine the long-term outcome of patients with endomyocardial fibrosis and to compare echocardiographic and haemodynamic data before and after ventricular endocardial resection. PATIENTS: Seventeen patients (11 women and six men; mean age 35.5 years) diagnosed with endomyocardial fibrosis at the University Hospital in Zurich, Switzerland from 1971 to 1995. Twelve patients (70%) had partial obliteration of both ventricles and in five patients (30%) the fibrotic lesions were limited to the left ventricle. METHODS: Fourteen of the 17 patients had surgical resection: fibrosis was resected from both ventricles in five patients and from the left ventricle only in nine patients. Ten patients had mitral valve replacement and two had tricuspid valve replacement. Left ventricle endocardial resection was done without reconstruction or replacement of the atrioventricular valve in three patients. Preoperative and postoperative echocardiographic data were available for 11 patients and haemodynamic data for six patients. Patients were followed up for 0.4-19 years (mean 8.6). RESULTS: Preoperatively four patients were NYHA functional class IV and 10 were class III; postoperatively one patient was class III, seven class II, and six class I. Preoperatively, echocardiography showed obliteration of the left ventricular apex and inflow tract in all patients, which decreased or disappeared after surgery. Left ventricular end diastolic pressure decreased from 25 mm Hg before surgery to 14 mm Hg after successful resection of the fibrosis. Left ventricular and diastolic volume (normal 93 (17) ml/m2) increased from 65 ml/m2 to 97 ml/m2 (p < 0.05) after surgery. Ejection fraction was normal preoperatively (57%) and decreased slightly (52%) after surgery. One patient died five months after surgery from heart failure. Four surgically treated patients died during the follow up period: one each from systolic dysfunction, recurrence of endomyocardial fibrosis, pneumonia, and food poisoning. Overall survival was 65% at five years and 59% at 10 years; the survival rates of the operated patients was 72% and 68%, respectively. Only one of the medically treated patients survived longer than three years from diagnosis. CONCLUSIONS: Endomyocardial fibrosis is a rare disease in European countries and is found mainly in women. The clinical picture is characterised by severe congestive heart failure but heart size is only moderately increased. Systolic performance is normal or only slightly depressed despite severe restriction to filling, atrioventricular valve regurgitation or both. Partial obliteration of the right and/or left ventricle may be detected by echocardiography. Endocardial resection with atrioventricular valve replacement is the treatment of choice with appreciable postoperative improvement and 10 year survival of approximately 70%.

Adolescent↗
PubMed1998

Situs inversus donor heart successfully transplanted.

Orthotopic heart transplantation was successfully performed in a 62-year-old man by use of a heart harvested from a donor with situs inversus. This procedure is a reasonable alternative when no other donor is available. The technique of this operation is described here. A month later the patient was discharged in good condition and is still doing well 1 year after the transplantation.

Heart Transplantation↗
PubMed1998

[How to do: initial experiences with a new device in minimally invasive heart surgery].

A special surgical technique is required for minimal-invasive cardiac surgery. The view for the coronary artery anastomosis under beating heart conditions is important and coronary artery blood might prevent a clear view of the opened coronary artery vessel. A new system called VisoFlo promises to improve visualisation at the surgical site. VisoFlo delivers a column of air to help provide a clear view of anastomosis site and in addition has a controllable mist to help prevent desiccation of the graft and surrounding tissue. This system was tested on 45 patients with coronary-artery-bypass graft surgery under beating heart conditions and at 65 patients with standard coronary-artery-bypass graft surgery. Our conclusions are, that the VisoFlo system is easy to use, guarantees a clear view of the anastomosis site and the surgical work will not be impaired.

Anastomosis, Surgical↗
PubMed1998

Tissue engineering: a new approach in cardiovascular surgery--seeding of human fibroblasts on resorbable mesh.

INTRODUCTION: In tissue engineering the material properties of synthetic compounds are manipulated to enable delivery of dissociated cells onto a scaffold in a manner that will result in in vitro formation of new functional tissue. The seeding of human fibroblasts on resorbable mesh is a precondition of a successful creation of human tissue such as autologous cardiac valves. MATERIAL AND METHODS: Polymeric scaffolds (n = 12) composed of polyglycolic acid (PGA) with a fiber diameter of 12-15 mm and a polymer density of 70 mg/ml were used as square sheets of 0.3 x 1 x 1 cm. Fibroblasts (passage 5), harvested from human foreskin, were seeded (3.4 x 10(6)) and cultured over a 3 week period on a PGA mesh. RESULTS: Microscopic examination of the seeded mesh demonstrated that the human fibroblasts were attached to the polymeric fibers and had begun to spread out and to divide. Electron microscopy showed a continuous distribution and formation of the cells throughout the "polymeric architecture". Spotlike hydrolysis of PGA fibers was observed. After 3 weeks the seeded scaffolds resembled a solid sheet of tissue. CONCLUSION: These preliminary results, successful seeding of human fibroblasts on a PGA mesh, represent a first basic step on the way to construct human tissue such as autologous cardiac valves and demonstrate that tissue engineering might be a promising new device in therapy of cardiovascular disease.

Cells, Cultured↗
PubMed1998

[The significance of endothelial adhesion molecules in heart surgery].

Myocardial ischemia and reperfusion is a common event in cardiovascular surgery patients. The endothelium has been shown to play a key role in the injury suffered after ischemia and reperfusion. When endothelial cells became hypoxic followed by reoxygenation they become activated to express endothelial adhesion molecules followed by the migration of neutrophils into the tissue. These changes may contribute to the early postoperatively myocardial dysfunction. An increased understanding of the interaction between leukocytes and endothelium may allow to develop new therapies in future.

Animals↗
PubMed1998

Wash out technique for proximal anastomosis in atherosclerotic ascending aorta.

BACKGROUND: Especially among elderly patients embolisms originating from atheromatous plaques in the ascending aorta are responsible for cardiac and cerebral events during coronary bypass surgery. Unfortunately smooth atheromatous degeneration of the aorta often can not be detected even by transoesophageal echocardiography. METHODS: In four patients with unexpected atheromatous material of the punched ascending aorta the so called "wash out technique" was performed. A side-to-end anastomosis between a segment of vein and the partially clamped ascending aorta was performed. For several minutes the ascending aorta was left to bleed through the venous stump. Without further manipulation of the ascending aorta the coronary bypass graft was completed by an end-to-end anastomosis between the venous stump and the venous graft. Oral anticoagulation in combination with a low dose platelet antiaggregation drug was given for at least one year. RESULTS: All patients had an uncomplicated postoperative course, especially with regard to neurological damage or ECG changes. CONCLUSIONS: In patients with unexpected atheromatous pathology of the ascending aorta the "wash out technique" of coronary artery bypass grafting minimises direct embolisation into the cardiac area perfused by the new bypass grafts.

Aorta, Thoracic↗
PubMed1997

[Aortic valve insufficiency in Crohn disease].

We report on a 39-year-old man with Crohn's disease who was admitted with cardiogenic shock after a short history of progressive dyspnea. Echocardiographic examination (transthoracic echocardiography) showed severe aortic regurgitation, mild mitral regurgitation, and enlargement of the sinus of Valsalva and of the ascending aorta at the level of the right pulmonary artery. The left ventricular ejection fraction was 30%. After aortic valve replacement, histologic examination of the ascending aorta showed chronic aortitis resembling syphilitic aortitis (serology for syphilis was negative) and HLA B27 related aortitis. The aortic valve showed deformation and thickening of the cusps by fibrous tissue without evidence of endocarditis. The patient remained well after surgery and echocardiographic examination 6 months later showed normal function of the aortic valve prosthesis. The diameter of the sinus of Valsalva and of the ascending aorta was slightly bigger, possibly indicating ongoing destruction. The left ventricular ejection fraction nearly normalized. It seems possible that this type of aortitis, characterized by its proximity to the valve ring, is another extraintestinal cardiac manifestation of Crohn's disease. The possibility of ongoing destruction of the sinus of Valsalva and of the ascending aorta after valve replacement makes regular echocardiographic control necessary.

Adult↗
PubMed1997

[Early results in the surgical treatment of type B aortic dissection].

In contrast to type A aortic dissection, the indication for acute surgical repair as treatment of choice in type B aortic dissection is not the actual dissection, but the complications resulting from the dissection (rupture, potential rupture and ischemic syndromes of the aortic branches). Between 1978 and 1994, 92 patients underwent surgical repair of type B aortic dissection at our institution. Following diagnostic confirmation by echocardiography and/or CT scan, all patients received conservative antihypertensive therapy. 52% of the patients underwent emergency surgical repair. Symptoms prompting surgical repair were: visceral ischemia (23%), pleural effusion (19%), paraparesis (17%), refractory hypertension (12%), further aortic enlargement (12%), and rupture (10%). In chronic type B aortic dissection, the main symptom in 84% of the cases was further enlargement of the aorta. The early mortality decreased in the course of initial treatment from 33% to 16%, and to 8% after exclusion of patients operated on for ruptured aorta. Improved early mortality has led to an increase in acute surgical repair. In cases of chronic dissection, strict antihypertensive therapy is indicated and regular checks on the width of the aorta, as well expeditious diagnostic confirmation of its enlargement, are important.

Acute Disease↗
PubMed1997

Reduced coronary flow reserve during exercise in cardiac transplant recipients.

BACKGROUND: Coronary flow reserve (CFR) is reduced in a majority of patients after heart transplantation (HTx). Pharmacological interventions, however, provide only limited information on CFR under physiological conditions. Thus, CFR during exercise was evaluated in the present study. METHODS AND RESULTS: Coronary angiography was performed at rest and during supine bicycle exercise in 35 patients early (2 to 3 months; n = 10) or late (1 to 6 years; mean, 2.5 years; n = 25) after HTx and in 8 controls (C). CFR was determined by parametric imaging after administration of 10 mg intracoronary papaverine, during exercise, and after 1.6 mg sublingual nitroglycerin. Epicardial coronary artery size was measured by quantitative coronary angiography. CFR after papaverine was normal early (3.6 +/- 0.5 versus C, 3.6 +/- 0.7; P = NS) and late (3.8 +/- 1.3 P = NS) after HTx. During exercise, CFR was normal early (3.1 +/- 0.6 versus C, 3.9 +/- 0.9; P = NS) but decreased late (2.3 +/- 0.6; P < .01) after HTx. The increase in coronary cross-sectional area during exercise was also diminished late after HTx (14 +/- 10% versus C, 22 +/- 10%; P < .05). Both exercise-induced CFR (r = -.39, P < .05) and coronary vasodilation (r = -.44, P < .01) were inversely correlated with time after HTx. CONCLUSIONS: CFR during exercise is normal early but reduced late after HTx, whereas CFR after papaverine administration is maintained. This difference between physiological and pharmacological vasodilation suggests progressive endothelial dysfunction after HTx.

Adult↗
PubMed1997

[Severe aortic valve diseases and aortic isthmus stenosis in adults. Incidence, clinical aspects and long-term results of surgical treatment].

Severe aortic valve disease is a rare complication of coarctation in adults. Between 1961 and 1990 aortic valve replacement was performed after or combined with the operation of coarctation in 24 adults (4% of entire population operated for coarctation). Bicuspid aortic valves were present in 2/3 of patients. In 10 patients (7/10 with aortic stenosis) coarctation was operated early (mean age 24 years) and aortic valve late (mean age 40 years): in 14 (10/14 with aortic regurgitation, mean age 40 years) aortic valve and coarctation were operated simultaneously (8 patients) or staged within 6 months (6 patients). Additional surgical interventions on the dilated aorta ascendens were performed in 8, mitral valve replacement in 2 and aorto-coronary bypass in 1 patients. Early mortality was 2/24 (8%) and was similar in simultaneously (1/8) and staged (1/14) operated cases: 10 year survival was lower than in an age-matched group of 72 patients with aortic valve disease of similar severity operated during the same period (70% vs 88%, p < 0.01): 6/7 late deaths were cardiac; 5/5 pts with preoperatively severely increased end-diastolic (> 199 ml/m2) and 4/4 with end-systolic (> 90 ml/m2) left ventricular volumes and 2/2 with ejection fraction < 41% died late postoperatively. Severe aortic valve disease arised in 4% of adults with coarctation or after coarctation resection. The results of valve replacement in these patients were less successful due to high late mortality in cases with severe preoperative left ventricular dilatation and/or decrease of ejection fraction. Thus, close surveillance of patients after coarctation surgery, especially those with bicuspid valves, is mandatory for early detection of valvular disease and appropriate timing of valve replacement before left ventricular function begins to deteriorate.

Adolescent↗
PubMed1997

New approach to patency and flow assessment after left internal thoracic artery hypoperfusion syndrome with additional saphenous vein graft to the left anterior descending artery with phase-contrast magnetic resonance angiography.

OBJECTIVE: Perioperative and early postoperative flow reduction of a left internal thoracic artery conduit is a rare complication of myocardial revascularization and may lead to the potentially fatal left internal thoracic artery hypoperfusion syndrome. It has been advocated that an additional vein graft be placed to the distal left anterior descending artery to provide sufficient myocardial perfusion. Some evidence exists, however, that this high-flow vein might lead to competing or even backward flow through the internal thoracic artery. METHODS: In the past 2 years, 21 patients received an additional vein graft to the distal left anterior descending artery for left internal thoracic artery hypoperfusion syndrome. Nineteen of these patients were available for magnetic resonance imaging. Early (< 6 months) and late (> 12 months) postoperative flow measurements, both in the left internal thoracic artery and in the saphenous vein grafts, were performed by means of conventional and a segmented k-space phase-contrast magnetic resonance angiography technique. RESULTS: Early magnetic resonance examinations indicated that all conduits had adapted to the coronary flow type with predominant diastolic perfusion. Patency rate both at the early and at the late study was 100%. No concurrent flow, flow reversal, or steal phenomena were observed. Mean flow rates were 49.2 ml/min for the left internal thoracic artery and 72.6 ml/min for the saphenous vein graft. CONCLUSION: On the basis of the flow data obtained with magnetic resonance angiography, the use of an additional saphenous vein graft as the treatment of choice in left internal thoracic artery hypoperfusion syndrome does not lead to occlusion of the artery. Conduit flow adaptation to the diastolic predominance occurs in the first 6 months after operation.

Coronary Vessels↗
PubMed1997

In situ repair of aortobronchial, aortoesophageal, and aortoenteric fistulae with cryopreserved aortic homografts.

PURPOSE: The surgical treatment of fistulae that originate from aortic aneurysms or prosthetic aortic grafts carries a high mortality rate. We investigated whether in situ repair with cryopreserved aortic homografts would improve the outcome. METHODS: Between April 1994 and June 1996, 11 patients (mean age, 62 +/- 10 years) with aortobronchial, aortoesophageal, or aortointestinal fistulae originating from mycotic aneurysms (five of 12) or prosthetic aortic grafts (six of 12) underwent in situ replacement of the thoracic (seven of 10) or abdominal (four of 10) aorta with homografts. Emergency surgery was performed in eight of 11 patients (73%). RESULTS: The hospital mortality rate was 9%; there was one sudden cardiac death on the seventh postoperative day. The mean hospital stay was 42 +/- 26 days (range, 21 to 90 days). After surgery, antibiotics were given for 38 +/- 6 days (range, 28 to 42 days). Neither reinfection, suture line rupture, nor anastomotic aneurysms were observed by magnetic resonance angiography, computed tomography, angiography, or transesophageal echocardiography after 14.3 +/- 8.2 months (range, 6 to 31 months). In one patient, percutaneous vascular stent placement was necessary after 18 months for an anastomotic stenosis of a thoracic homograft. CONCLUSIONS: In situ repair with cryopreserved aortic homografts seems to be a promising step in the treatment of aortobronchial, aortoesophageal, and aortointestinal fistulae. This technique has a low operative mortality rate and may prevent reinfection.

Aged↗
PubMed1997

Congenital aortopulumonary window: diagnosis, surgical technique and long-term results.

OBJECTIVE: Congenital aortopulmonary window is rare, often associated with other cardiac anomalies. Surgical repair as the only treatment should be performed before pulmonary vascular changes have developed. This study presents the long-term outcome after surgical correction for this condition. MATERIALS AND METHODS: Between 1971 and 1993, 13 patients with congenital aortopulmonary window were found. 10 had type I, 2 type II and 1 had type III. Concomitant cardiac anomalies were present in 10/13. Eleven patients were operated on at a mean age of 31.2 +/- 48.3 months (range 6 days-10 years). Thoracotomy was used in 3 and sternotomy in 9 patients. In 4/11, the aorto-pulmonary window was simply ligated, 4 had a transpulmonary approach and 1 combined with a transaortic approach. The aortopulmonary window was closed directly in 2 and with a Dacron patch in 1. Cardiopulmonary bypass was used in 6 patients. Associated anomalies in 10/11 patients. RESULTS: There was one operative death (9%): a six-day old boy with interrupted aortic arch died 6 h postoperatively due to low-cardiac output. The mean follow-up period is 8.1 +/- 7.3 years (range 2-24 years). Clinical examination, transaortic echocardiography and/or cardiac catheterization were obtained in the follow-up. There was no late death. All are in New York Heart Association (NYHA) class I. One had to be reoperated on for a recurrent shunt 29 months after ligation and one had angioplasty after 23 months for residual stenosis of the reimplanted right pulmonary artery. The actuarial survival rate is 90% after 1, 5 and 10 years. CONCLUSIONS: The surgical treatment of aortopulmonary window has a low risk, even if associated with major cardiac anomalies. Prompt operative treatment achieves excellent long-term results.

Actuarial Analysis↗
PubMed1997

Postoperative hemodynamics depend on cardiopulmonary bypass temperature: the potential role of endothelin-1.

OBJECTIVE: There is a growing body of evidence that perfusion temperature during cardiopulmonary bypass (CPB) influences postoperative systemic vascular resistance (SVR). The reason for this is not clear. Extracorporeal circulation can provoke raised plasma levels of endothelin-1 (ET-1), a very potent vasoconstrictor peptide produced by endothelial cells. We therefore analysed the effect of CPB temperature on postoperative vascular resistance and plasma concentrations of ET-1. METHODS: Thirty four patients undergoing elective coronary artery bypass grafting procedures were randomly assigned for either normothermic (37 degrees C, n = 17) or hypothermic CPB (28 degrees C, n = 17). Serial measurements of SVR and plasma ET-1 concentrations were performed before, during, and until 9 h after CPB measured. RESULTS: As a consequence of CPB, plasma ET-1 levels increased slightly in both groups. In normothermic patients, ET-1 reached maximal levels at the end of CPB whereas ET-1 levels in patients after hypothermic CPB had a tendency to further increase during the stay in the intensive care unit. Plasma ET-1 levels were significantly higher in patients 9 h postoperatively after hypothermic CPB (1.94 +/- 0.28 vs. 1.30 +/- 0.12 pg/ml, P = 0.033), which was associated with significantly higher systemic vascular resistance index (SVRI) in these patients (area under the curve; 1978 +/- 76 vs. 1626 +/- 69 dyne s/cm5 per m2, P = 0.003). Plasma ET-1 levels showed a positive correlation with postoperative SVRI (P = 0.008, r = 0.51) and a negative correlation with minimal rectal temperature during CPB (P = 0.006, r = 0.55). CONCLUSIONS: These results suggests that the hemodynamic differences after normothermic and hypothermic CPB might be mediated, at least in part, by temperature dependent changes in ET-1 plasma levels.

Adult↗
PubMed1997

The effect of the N-methyl-D-aspartate receptor antagonist dextromethorphan on perioperative brain injury in children undergoing cardiac surgery with cardiopulmonary bypass: results of a pilot study.

Experimental evidence indicates a role of the N-methyl-D-aspartate receptor in the pathogenesis of brain injury occurring during cardiac surgery with cardiopulmonary bypass (CPB). Dextromethorphan is a noncompetitive antagonist of this receptor with a favorable safety profile. Thirteen children age 3-36 months undergoing cardiac surgery with expected CPB of 60 minutes or more were randomly assigned to treatment with dextromethorphan (36-38 mg/kg/day) or placebo administered by naso-gastric tube. Dextromethorphan was absorbed well and reached putative therapeutic levels in blood and cerebrospinal fluid. Adverse effects were not observed. Mild hemiparesis developed after operation in one child of each group, and severe encephalopathy in one of the placebo group. Sharp waves were recorded in postoperative continuous electroencephalography in all placebo (n = 7) but only in 2/6 dextromethorphan treated children (p = 0.02). Pre- and postoperative cranial magnetic resonance imaging (MRI) revealed less pronounced ventricular enlargement in the dextromethorphan group (not significant). An increase of periventricular white matter lesions was visible in two placebo-treated children only. No elevations of cerebrospinal fluid enzymes were observed in either group. Although children with dextromethorphan showed less abnormalities in electroencephalography and MRI, dissimilarities of the treatment groups by chance diminished conclusions to possible protective effects of dextromethorphan at this time.

Brain Chemistry↗
PubMed1997

Biventricular assist using a portable driver in combination with implanted devices: preliminary experience.

Left ventricular assist systems with portable drive units are increasingly used in the clinical setting. However, such systems usually are not suitable for right ventricular support, and therefore, in the case of biventricular heart failure, they must be combined with other support devices that require additional drive consoles. As a result, most of the benefits of the wearable drive units (early mobilization and outpatient care) are lost. This present study was performed to evaluate biventricular support with implanted assist devices and a portable DC/battery-powered driver (Thoratec TLC-II). Electronic control by nonvolatile RAM accessible via RS232 interface, internal backup emergency battery, and optional manual activation are additional features of this 6 kg biventricular drive unit. In 3 bovine experiments (body weight 70 +/- 5 kg) partial cardiopulmonary bypass (CPB) was established, and two ventricular assist devices were implanted into a preperitoneal pocket on each side after connection to the right atrium and the pulmonary artery and to the left atrium and aorta, respectively. After weaning the patient from CPB, activated coagulation time (ACT) was kept at greater than 180 s, and biventricular support with the portable driver was activated. After 10 min, mean device flow stabilized at 3.5 +/- 0 L/min and remained at that level throughout the ensuing 6 h (3.5 +/- 0.3 L/min; NS). The heart rate moved from 130 +/- 13 beats per minute (bpm) at the end of CPB to 116 +/- 13 bpm after 10 min of assist (p < 0.05). Right atrial pressure moved from 11 +/- 2 mm Hg at the end of CPB to 13 +/- 3 mm Hg after 10 min of assist (not significant [NS]). Mean pulmonary artery pressure was 18 +/- mm Hg at the end of CPB and 17 +/- 5 mm Hg after 10 min of assist (NS). Left atrial pressure was 10 +/- 1 mm Hg at the end of CPB and 13 +/- 3 mm Hg after 10 min of assist (NS). Mean aortic pressure was 73 +/- 11 mm Hg at the end of CPB and 77 +/- 3 mm Hg after 10 min of assist (NS). Mixed venous oxygen saturation increased from 49 +/- 9% at the end of CPB to 58 +/- 10% after 10 min of assist (p < 0.05). The portable drive unit that was tested provides adequate power to maintain significant biventricular support with implanted right and left assist devices. The configuration of batteries tested driving two ventricles provides independence for 60 min.

Animals↗