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Biomedical subjects

M Turina

Publications and source records attributed to M Turina.

At least 199 records · Page 11Linked to original sources
PubMed1993

Coronary artery resistance and oxygen uptake during reperfusion: is there any difference between warm and cold cardioplegia?

To evaluate the effects of warm continuous versus cold intermittent blood cardioplegia on coronary blood flow patterns after prolonged cardioplegic arrest, nine pigs underwent cardiopulmonary bypass with 210 minutes of aortic cross-clamping. Antegrade blood cardioplegia was administered either cold intermittent (n = 4) or warm continuous (n = 5). During the first 30 minutes of reperfusion, there was decreased coronary blood flow with higher coronary vascular resistance in the cold group (mean +/- standard error; warm vs. cold: 30 min: flow: left anterior descending artery (LAD): 66 +/- 6 vs 36 +/- 4 ml/min, right coronary artery (RCA): 88 +/- 2 vs 61 +/- 4, p < 0.05, resistance: LAD: 33 +/- 3 vs 69 +/- 5 dyn.s.cm-5 x 10(3), RCA: 41 +/- 3 vs 58 +/- 8, p < 0.05). After one hour of reperfusion there were no differences between groups. Arterio-venous oxygen difference was higher in the cold group after 15 min (3.1 +/- 0.5 vs 4.8 +/- 0.3 ml O2/100 ml, p < 0.05) and 30 min (4.2 +/- 0.5 vs 6.2 +/- 0.7, p < 0.05) with equal values after 1 hour. During reperfusion there is reduced myocardial blood flow after cold intermittent blood cardioplegia. This may reflect superior myocardial protection with warm continuous cardioplegia.

Animals↗
PubMed1993

Coronary artery surgical technique.

The increased use of arterial conduits in coronary artery bypass grafting is reflected in numerous publications addressing indications, choice of conduits, and possible side-effects. Besides the internal thoracic artery, the right gastroepiploic artery is becoming established, and the inferior epigastric artery is being subjected to clinical trials. The latter conduit provides good patency and can be combined with the internal thoracic arteries, but harvesting must be done carefully to prevent local complications. Arterial conduits can lead to hypoperfusion, and additional saphenous vein grafting may become necessary; careful vasodilatation of the conduit before implantation is necessary. Xenografts and allogenic implants demonstrate poor late patency and should be used only as a last resort. Aprotinin reduces blood loss during surgery and seems to be particularly useful in reoperations; but it prolongs the activated clotting time and underheparinization can occur. Retrograde cardioplegia seems to be particularly indicated in reoperations, whereas topical cooling can be omitted. Coronary revascularization can be safely combined with carotid endarterectomy; the exact indication for this simultaneous procedure is still being explored.

Aprotinin↗
PubMed1993

Different effects of angiotensin-converting enzyme inhibition in human arteries and veins.

The renin-angiotensin system (RAS) participates in the regulation of vascular tone; its effects were studied in human internal mammary artery (IMA) and saphenous vein (SV) suspended in organ chambers for isometric tension recording. The angiotensin-converting enzyme (ACE) inhibitor enalaprilat (10(-7) M) markedly augmented endothelium-dependent relaxations to bradykinin in SV (concentration shift: 10-fold; n = 6; p < 0.005), but not in IMA; in both blood vessels, it had no effect on endothelium-dependent relaxations to acetylcholine. The contractions to angiotensin I (Ang I; 10(-7) M) were markedly inhibited by enalaprilat (10(-7) M) in SV (control: 34 +/- 6% of 100 mM KCl; treatment: 18 +/- 6%; n = 7; p < 0.05) but not in IMA (control: 33 +/- 4%; treatment: 30 +/- 6%; n = 7; NS) and abolished by the Ang II receptor antagonist DuP 753 (10(-7) M) in both blood vessels. Ang II (10(-7) M) induced more pronounced contractions than Ang I in IMA (63 +/- 4%) and SV (63 +/- 5%; n = 5-6; p < 0.05 vs. Ang I), which was markedly inhibited by DuP 753 (10(-7) M; IMA: 21 +/- 5%; SV: 32 +/- 5%; p < 0.05). Thus, in SV but not IMA, ACE inactivates bradykinin and thereby blunts endothelium-dependent relaxations to the peptide and converts Ang I to Ang II.

Acetylcholine↗
PubMed1993

Premature ICD battery depletion due to a defective lead adapter component: usefulness of extensive data logging.

Described herein is the usefulness of extensive data logging of third generation ICDs in a patient with premature ICD battery depletion due to a defective pace/sensing lead component. Due to noise artifacts, VT/VF detections occurred leading to inappropriate patient shock discharges and 2,267 internal charge dumps within 2 weeks. During manual manipulations at the ICD site, real-time intracardiac electrocardiogram and event markers revealed noise artifacts that were interpreted as VT/VF. Radiography confirmed slight movement of the pace/sensing lead pin out of the Y-adapter. Therefore, the design of adapter systems without screw fixation should be reviewed to ensure lead integrity. In the case of sudden increases in VT/VF recognition, defective sensing components must be considered.

Electric Power Supplies↗
PubMed1993

Infected endocardial pacemaker electrodes: successful open intracardiac removal.

UNLABELLED: The long-term results after open intracardiac removal of infected pacing electrodes are presented. METHODS: Between 1985 and 1990 open intracardiac removal of 19 infected pacing electrodes was performed in seven patients (six male and one female), with a mean age of 56 years. The indications were: persisting bacteremia in three; generator pocket infection in four; endocarditis in one; and ventricular tachycardia caused by retracted electrodes in one. All electrodes were fixed in the right heart and extraction by closed methods failed. Percutaneous catheter techniques were not applied in these seven patients. In five patients two ventricular electrodes had to be removed, and in two patients a single one. A total of seven atrial electrodes were removed in six patients (one electrode each in five patients; two electrodes in one patient). All atrial and two ventricular electrodes could be removed through a pursestring suture without use of a pump oxygenator. For the removal of ten ventricular electrodes in six patients (two electrodes each in four patients; 1 electrode each in two patients) a right-sided atriotomy was necessary with cardiopulmonary bypass (CPB). Simultaneously, five new pacing systems were implanted. RESULTS: There were no early or late mortalities. In January 1991, all seven patients are alive and in a mean New York Heart Association Class 1,3 of heart failure after a mean interval of 33 months. In all cases the infection could controlled with a simultaneous antimicrobial chemotherapy and the postoperative period was free of major complications. CONCLUSION: Open intracardiac removal of retained pacing electrodes with or without use of CPB is a safe procedure without major complications. It is mandatory for all infected pacing electrodes that cannot be extracted by closed methods.

Adult↗
PubMed1993

Mycotic aneurysm of the abdominal aorta: extra-anatomic versus in situ reconstruction.

Between 1973 and 1991, 12 patients with mycotic aneurysm of the abdominal aorta underwent operation. There were four elective and eight emergency procedures. In situ reconstruction was performed in six patients and extra-anatomic reconstruction with axillobifemoral bypass grafting in six. The hospital mortality rate was 25% (three patients) and another three died during the follow-up period of mean 5.5 years. Descending aorta-bifemoral bypass was performed in two patients without signs of chronic local infection 1 and 2 years after previous axillobifemoral bypass. Late complications were peripheral embolization in one patient after in situ reconstruction and a total of five thromboses of the axillofemoral bypass in three patients. Extra-anatomic bypass grafting remains the method of choice for the majority of patients with mycotic aneurysm of the abdominal aorta. In situ reconstruction seems to be an appropriate procedure for a highly selected group of patients.

Aged↗
PubMed1993

Anomalous left pulmonary artery (pulmonary sling): result of a surgical approach.

Between 1977 and 1992, four infants with an anomalous left pulmonary artery and subsequent compression of the tracheobronchial tree were operated on at the University Hospital Zurich. The operation consisted of mobilization of the abnormal left pulmonary artery with reimplantation into the main pulmonary trunk in three patients; the left pulmonary artery was transected and restored in front of the trachea by end-to-end anastomosis in one. Mean follow-up was 7 years (range 2 months to 14.3 years). There were no early and no late deaths. All patients have shown significant symptomatic improvement without respiratory infection or disturbance of normal life activities. Surgical therapy in this rare condition can be safely undertaken with good long-term results. In symptomatic patients the operation should be performed early before occurrence of severe respiratory symptoms and bronchial collapse.

Airway Obstruction↗
PubMed1993

[Long-term results in the dog carotid artery with small lumen vascular prostheses with microvascular endothelial cells].

In this study we evaluated the long-term results of microvascular endothelial cell seeding of small diameter Dacron grafts with omentally derived cells in a canine model. 6 cm long and 4 mm I.D. seeded Dacron prostheses were implanted end-to-end in the carotid position in 12 dogs for 6 to 12 months. Microvascular endothelial cells were enzymatically harvested from omentum prior to implantation and seeded onto Dacron grafts with a seeding density of 1.5 x 10(6) cells/cm2 of the graft. The antiplatelet therapy (Aspirin, Dipyridamol) was administered for 4 weeks postoperatively. All seeded grafts were patent throughout the study. The thrombus-free surface area for seeded grafts was 99.6 +/- 0.8% and 99.6 +/- 0.9% at 6 months and one year, respectively. Scanning electron microscopy revealed a confluent endothelial layer. We concluded that endothelial cell seeding of smaller-diameter prosthetic vascular grafts with omentally derived endothelial cells obtained excellent long-term patency rate in the canine model.

Animals↗
PubMed1993

[Is normothermic cardiopulmonary bypass associated with increased morbidity?].

UNLABELLED: There is some evidence of improved myocardial protection with warm continuous blood cardioplegia. Warm cardioplegia however implies warm (normothermic) cardiopulmonary bypass (CPB). We evaluated retrospectively the influence of bypass temperature on the intra- and postoperative course of 121 patients, operated on for valvular and/or coronary artery disease. Only elective procedures with continuous blood cardioplegia were included. The patients were divided in two groups: warm group (n = 78): normothermic CPB (venous temperature > 33 degrees C) cold group (n = 43): hypothermic CPB (< 33 degrees C). RESULTS: normothermic CPB resulted in a significantly shorter CPB time (84 + 3 min vs. 98 +/- 6 min, p = 0.02, mean +/- 1 standard error of the mean). In addition there was a higher need for vasoconstrictive drugs during cold CPB (Noradrenalin: 19 +/- 3 micrograms vs. 90 +/- 32 micrograms, p = 0.003). There was no difference in enzyme levels on the first postoperative day (amylase, creatinkinase, creatinin), in postoperative complication rate (resuscitations, rethoracotomies, cerebrovascular incidents) and mortality (warm 3% vs. cold 2%) between the two groups. The postoperative time until extubation however was significantly shorter in the warm group (33 +/- 5 h vs. 60 +/- 11 h, p = 0.04). CONCLUSION: there is no evidence of increased morbidity due to normothermic CPB. The shorter time until extubation may be due to a improved postoperative lung function and/or a more stable hemodynamic postoperative course after normothermic CPB.

Body Temperature↗
PubMed1993

[Are the advantages of percutaneous catheterization technique gained by increased blood trauma?].

UNLABELLED: The development of thin-walled cannulas which can be introduced by percutaneous technique into femoral artery and vein has revived interest in emergency cardiopulmonary support (CPS). To assess possible blood damaging effect due to the small-bore cannulas, 8 in vitro perfusions were performed with two parallel pump circuits: one circuit with a 17 F arterial and a 21 F venous cannula, one circuit without cannulas (control). The circuits were filled with 61 of bovine blood and run for 6 hours at a temperature of 37 degrees C and a flow of 4 l/min. Serial blood samples were taken before and during the experiment. There was a significantly higher level of free plasma haemoglobin (pl Hb) and a decreased number of leukocytes (Lc) after 6 hours of perfusion in the group with percutaneous cannulas as compared with control (pl Hb: 63.2 +/- 0.3 vs. 26.3 +/- 4.1 mumol/l, p < 0.05, Lc: 2.4 +/- 0.6 vs. 4.6 +/- 0.8 x 10(9)/l, p < 0.05, mean +/- se). CONCLUSION: percutaneous cannulas are associated with an increased blood trauma. If extended cardiopulmonary support is considered (more than several hours), percutaneous cannulas should be replaced by large-bore cannulas.

Animals↗
PubMed1993

[Development of surgical treatment of transposition of great vessels in the last 15 years. Methods and early results].

Between 1978 and June 1992, 213 patients were operated for transposition of the great arteries at our institution. 148 patients underwent atrial repair, 41 patients an anatomic repair and 24 patients only palliation. Since 1986 the anatomic repair has progressively replaced the arterial repair: 1978-1986 95-100% atrial repair, 1992 100% anatomic repair. At operation the average age of the patients treated by atrial repair was 22 months, resp. 10 months from 1986 to 1991, for anatomic repair 9 months, resp. 46 days in 1991/1992. The 30-day mortality for atrial repair was 11% (17/148), for anatomic repair 22% (9/41), resp. 12% (3/24) in 1991/1992. Potentially superior long-term results for anatomic repair are possible, but cannot be demonstrated at present.

Child↗
PubMed1993

[The dynamics of blood composition changes in leukocyte filtration during cardiopulmonary bypass. Preliminary results].

Activation of leukocytes (especially neutrophils) during cardiopulmonary bypass (CPB) causes a reperfusion injury through the release of oxygen free radicals and formation of microvascular occlusions. Leukocyte filtration during CPB could solve these drawbacks. We investigated the selectivity of leukocyte filtration by fifteen patients undergoing coronary artery bypass surgery. Leukocyte depleted patients (n = 8) had a leukocyte filter incorporated in the bypass circuit. We evaluated the number of lymphocytes, neutrophils and platelets as well as hematocrit values at following time points: a) before CPB, b) 15 min after the start of CPB, c) before the administration of protamin and d) 3 hours after the CPB. No statistically significant changes of hematocrit values, lymphocyte or platelet counts between control and leukocyte depleted group of patients were observed. However, the use of leukocyte filter caused significant decrease in number of circulating neutrophils at 15 min after begin of CPB (1.20 +/- 0.17 x 10(9)/l for leukocyte depleted patients and 1.90 +/- 0.42 x 10(9)/l for control group of patients, p < 0.05). Our temporary results indicate the selectivity of leukocyte filtration during the cardiopulmonary bypass.

Adult↗
PubMed1993

[Myocardial protection: is retrograde equal to antegrade perfusion?].

The adequacy of retrograde delivery of cardioplegic solution to the right ventricle ist controversial. To evaluate this issue, we excised the plegic heart in 11 bovine experiments and infused an India ink solution (10 ml of India ink in 300 ml NaCl 0.9%) into the coronary sinus (n = 7) at a pressure of 60 cm H2O and into the aortic root (n = 4) at a pressure of 120 cm H2O. After fixation, the ventricles were cut in 11 transversal slices. The portion of coloured (= perfused) ventricular myocardium was calculated with computer-aided morphometric analysis. With antegrade infusion, 95 +/- 5% (mean +/- standard deviation) of the left ventricular volume (left ventricular free wall plus interventricular septum) was stained, with retrograde infusion 94 +/- 3%. Perfusion of the right ventricle was significantly lower with retrograde infusion (antegrade infusion 93 +/- 8%, retrograde 45 +/- 13%, p < 0.001), especially in the basal segments (basal vs. apical: 16 +/- 26% vs. 82 +/- 5%, p < 0.001). The adequate delivery of retrograde infusion to the left ventricle and septum allows good left ventricular myocardial protection with retrograde cardioplegia. Because the retrograde delivery to the right ventricle is markedly inadequate and nonuniform, the quality of right ventricular protection with retrograde cardioplegia has to be questioned.

Animals↗
PubMed1993

[Surgery of endocarditis in the drug dependent and HIV patient. A prospective comparison with conservative treatment].

The incidence of infective endocarditis in drug addicts is increasing with the spreading of intravenous drug abuse. The tricuspid valve is the most commonly involved valve followed by the mitral valve. We evaluated prospectively 22 patients with a mean age of 23 years, presenting with addiction-associated endocarditis endocarditis and referred to our institution during a three-year period. The tricuspid valve was involved in 13 instances, mitral valve in 4, mitral plus tricuspid valve in 5 patients and aortic valve in 1 case. Staphylococcus aureus was the most frequent infective organism (15x), followed by Streptococci (4x), Corynebacteria (2x) and one case with a mixed infection. Six patients were positive for an HIV-infection and 17 had evidence for a chronic viral hepatitis. Ten patients (3 of them HIV-seropositive) were treated surgically. Resection of the tricuspid valve with (1x) or without replacement (4x), resection of vegetations and valve repair (2x), mitral valve replacement (2x), aortic valve replacement (1x) were performed. In case of tricuspid endocarditis, the decision whether to proceed with resection, repair or replacement with a bioprosthesis was taken according to valve pathology and the psycho-social situation of the patient. When the vegetations involved only one leaflet and could be removed easily, vegetectomy with annuloplasty or with repair using autologous pericardium was performed. Valvulectomy without replacement was the chosen method for those where persistent or recurrent drug abuse could not be excluded. A bioprosthesis was inserted when the tricuspid valve was completely destroyed and there was a proven abstinence from drugs over a period of several weeks preoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

AIDS-Related Opportunistic Infections↗
PubMed1993

Antibiotic prophylaxis in cardiovascular surgery: a prospective randomized comparative trial of one day cefazolin versus single dose cefuroxime.

With the intention of reducing prophylactic antibiotic dosage, previous studies in the Zurich University Hospital have shown that a one/day prophylactic antimicrobial regimen with cefazolin was as effective as a single dose of ceftriaxone. In this prospective randomized study one day cefazolin prophylaxis (1 g q 8 h i.v.) was compared with a single dose of cefuroxime prophylaxis (1.5 g). In cases of cardiopulmonary bypass 0.75 g was added in the priming solution. In case of re-operation prophylaxis was repeated. 496 patients were enrolled in the study protocol; 78 patients were subsequently excluded. Of the remaining patients 224 (158 male, 66 female, mean age 61) were in the cefazolin group and 194 (142 male and 52 female, mean age 60) in the cefuroxime group. Mean duration of the intensive care unit (ICU) stay was three days in both groups and mean hospital stay was 16 days in the cefazolin group and 15 days in the cefuroxime group. The overall postoperative infection rate was 15.3%; 18.8% in the cefazolin group and 11.3% in the cefuroxime group. The statistical differences were found as in trend (p = 0.095). The lower incidence of infectious complications in the single cefuroxime dose group may indicate an improvement in effectiveness of antimicrobial prophylaxis: it offers patients a reliable antimicrobial protection. In addition, the single dose prophylaxis has the advantage of easier handling, reduced dosage frequency and lower cost.

Bacterial Infections↗
PubMed1993

[Early results of surgical revascularization of the subclavian artery].

In the last 14 years (1978 to 1991) in the Clinic of Cardiovascular Surgery, University Hospital Zurich, 72 patients were operated due to obstruction of the subclavian artery. The left side was affected in 46/72 (63.9%), the right side in 21/72 (29.2%), both sides in 5/72 (6.9%) patients. Only thrombendarterectomy has been done in 48/72 (66.7%), followed by carotis-subclavian-bypass (9/72, 12.5%). Furthermore the following techniques were applied: endarterectomy and patch in 6/72 (8.3%), aorta-subclavian-bypass in 5/72 (6.9%), bypass between proximal and distal subclavian artery in 2/72 (2.8%), resection and graft-interposition in 1/72 (1.4%) cases. As well as operation-related reactions of soft tissues (hematoma, swelling) the following complications have been recognized: re-stenosis with embolus or intima-flap in 8/72 (11.1%) cases, 3-times persistent, paralysis of the vocal cord in 3/72 (4.2%) cases, phrenic nerve paralysis in 2/72 (2.8%), in two separate cases Horner's syndrome and pneumothorax. The oldest patient (81 years) died 10 days after operation due to hemorrhage, in spite of 3 re-thoracotomies. Additional complications arose independently of the subclavian operation (atrial flatter, heart-infarction, lungoedema, exitus following extensive heart-operation with valve-replacement and aorto-coronary bypass).

Adult↗