Biomedical subjects
M Turina
Publications and source records attributed to M Turina.
Infectious complications in 100 consecutive heart transplant recipients.
Clinical and laboratory data on infectious complications in 100 consecutive heart transplant recipients were analyzed retrospectively. The mean length of follow-up was 651 +/- 466 days. All patients received a basic immunosuppressive regimen including cyclosporine (whole blood target trough level 400-600 micrograms/l), azathioprine (1 mg/kg/day) and prednisone (0.15 mg/kg/day). Early rejection prophylaxis consisted of polyclonal rabbit antithymocyte globulin (ATG) (4 mg/kg/day for 4 days) in the first 57 patients and monoclonal murine OKT-3 (5 mg/day for 14 days) in the remaining patients. The primary cause of death was infection in three patients and rejection in 16 (p < 0.001). The incidence of infection was 0.96/patient/year (n = 179); 95 infections were nosocomial (53%), 47 community-acquired (26%) and 37 opportunistic (21%). The number of hospitalizations due to infections was fewer than that due to rejection (53 versus 246 respectively, p < 0.0001), but the mean length of hospital stay was longer in the first group (13.85 +/- 10.92 days versus 3.48 +/- 2.28 days, p < 0.001). Previous early rejection prophylaxis with OKT-3 was associated with a greater number of opportunistic and nosocomial infections compared to prophylaxis with ATG (p < 0.05), as was treatment with ATG and steroid pulses compared to steroid pulses alone in cases of opportunistic infection (p < 0.05).
Should cardiac transplantation for congenital heart disease be delayed until adult age?
The number of pediatric heart transplantations for complex congenital heart disease has increased over the last years, but little experience has been reported in adolescent and adult populations. Between 1987 and 1992, 14 patients (mean age 33.2 years, range 14 to 51 years) were transplanted in our institution because of structural congenital heart disease (n = 9) or other rare disorders of the endomyocardial morphogenesis (n = 5). The main diagnosis included transposition of the great arteries, congenitally corrected transposition of the great vessels, left superior vena cava, tricuspid atresia with right ventricular hypoplasia, double outlet right ventricle with transposition, left ventricular sinusoidal malformation and right ventricular dysplasia. In several cases there were additional intracardiac malformations, including ventricular septum defect, atrial septum defect as well as different forms of pulmonary stenosis. Seven patients had undergone one or more palliative repairs that consisted of modified Blalock-Taussig shunts, Glenn's cavopulmonary anastomosis, Waterstone shunt, Blalock-Hanlon atrioseptectomy and Brock pulmonary valvotomy. Two patients had undergone Senning procedure for transposition of the great arteries. The donor cardiectomy was modified in order to include complete inflow and outflow tissue in the explant and transplantation could be performed without prosthetic material in all patients; deep hypothermic cardiac arrest was never necessary in this series. There was no early or late mortality after a mean follow-up of 37 months (range 4 to 74 months); postoperative echocardiography and cardiac catheterization demonstrated perfect anatomical and functional results in all patients. Adolescent and adult patients with complex congenital cardiac diseases can be transplanted with a very low perioperative risk, even after several prior operative procedures.(ABSTRACT TRUNCATED AT 250 WORDS)
Continuous thermodilution measurement of cardiac output: in-vitro and in-vivo evaluation.
The current study was designed to evaluate a method for continuous measurement of cardiac output. The system consists of a modified pulmonary artery catheter that uses the thermodilution principle for determination of cardiac output. The evaluation was performed in vitro and in vivo. In-vitro evaluation was performed using a simple flow bench model (flow 2-9 L/min). Both continuous and bolus thermodilution methods were compared. Both methods showed good correlation with the pump flow calibrated using a volumetric tank and timer (correlation coefficient (r) for bolus thermodilution = 0.92, r for continuous thermodilution = 0.90). In-vivo evaluation was performed in six bovine experiments. Data from a total of 87 pairs of bolus versus continuous measurements were obtained. The cardiac output ranged from 1.9 to 8.9 L/min. The absolute measurement bias was not significant (mean: -0.07 L/min; 95% confidence limits: -0.87 and 0.73 L/min). The squared correlation coefficient from linear regression was 0.92. The results from this study suggest that the new continuous thermodilution measurement system for cardiac output provides accurate data in vitro and in vivo. Continuous monitoring of cardiac output adds a new dimension for evaluation of the patient's hemodynamic profile. Furthermore, significant volume load due to bolus thermodilution measurements can be avoided.
Treatment of internal mammary artery malperfusion syndrome by additional venous graft: early postoperative angiographic results.
BACKGROUND: Internal mammary artery malperfusion syndrome is caused by an acute imbalance between myocardial demand and nutritional support through the mammary artery. METHODS: We performed early angiography in 11 consecutive patients in whom the perioperative course suggested mammary artery malperfusion. All patients received an additional saphenous vein graft distally to the mammary artery anastomosis. RESULTS: Postoperative angiography revealed patent mammary artery and vein graft in 10 patients (three with a markedly reduced caliber of the arterial graft). CONCLUSION: Additional vein graft is the treatment of choice in mammary artery malperfusion syndrome; it does not lead to occlusion of the internal mammary artery.
Propionibacterium acnes as a cause of aggressive aortic valve endocarditis and importance of tissue grinding: case report and review.
A case of prosthetic valve endocarditis with Propionibacterium acnes is described. The diagnosis was documented by histology and isolation of P. acnes from both blood and anulus tissue. Grinding of the tissue, which was first omitted to avoid contamination, was indispensable for cultivating the agent. The literature for P. acnes endocarditis is reviewed.
Thrombin-induced endothelium-dependent inhibition and direct activation of platelet-vessel wall interaction. Role of prostacyclin, nitric oxide, and thromboxane A2.
BACKGROUND: Platelet-vessel wall interaction plays an important role in acute cardiovascular disorders. Thrombin is a potent platelet activator but also has profound effects on the endothelium. Endothelial cells possess antithrombotic activity by releasing nitric oxide and prostacyclin, both potent vasodilators and platelet inhibitors. We studied the role of thrombin as a regulator of platelet-vessel wall interaction in isolated human arteries suspended in organ chambers for isometric tension recording. METHODS AND RESULTS: In arteries with endothelium, thrombin (0.01 to 1 U/mL) induced endothelium-dependent relaxations, which were reduced by the nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME; 10(-4) mol/L) and/or indomethacin (10(-5) mol/L). Human platelets (75,000/microL) evoked only marginal contractions in arteries with endothelium (3 +/- 3% of the contraction to KCl 100 mmol/L; NS), which were markedly enhanced by endothelial removal (22 +/- 4%; P < .05). Thrombin (1 U/mL) did not affect the response to platelets in arteries with (6 +/- 5%; NS) but induced a huge contraction in rings without endothelium (53 +/- 6%; P < .01 versus control without endothelium). The potent contraction to thrombin-activated platelets (1000 to 75,000/microL) in arteries without endothelium was markedly inhibited by the thromboxane A2 synthetase/receptor antagonist ridogrel (10(-5) mol/L; P < .005 versus control) and the single-acting thromboxane receptor blocker SQ-30741 (10(-7) mol/L; P < .01 versus control). CONCLUSIONS: Thus, thrombin directly stimulates platelets to release thromboxane A2, inducing potent vasoconstriction, which is prevented by the simultaneous thrombin-induced release of prostacyclin and nitric oxide from endothelial cells. In arteries devoid of functional endothelial cells, as occurs in patients with coronary artery disease, a combined inhibition of thromboxane production and action provides a potent therapeutic tool to interfere with the thrombin-induced activation of platelet-vessel wall interaction.
Surface treatments for perfusion devices.
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Heparin surface coated hard shell venous reservoirs: experimental evaluation ex vivo.
The present study was designed for ex vivo evaluation of a heparin coated hard shell venous reservoir in comparison to uncoated control reservoirs. An open chest bovine right heart bypass model (n = 9, bodyweight 72 +/- 6 kg) with passive blood drainage from the right atrium into the venous reservoir and active retransfusion into the pulmonary artery (roller pump) was selected for this purpose. Clear priming was used for the open perfusion circuit. No heparin was given before or during the evaluation period which was scheduled for 6 hours. Reservoir blood flow was at the beginning 3.5 +/- 0.6 l/min for coated versus 3.4 +/- 0.3 l/min for uncoated (NS). After 6 hours, blood flow was 3.3 +/- 0.1 l/min for coated versus 2.7 +/- 0.4 l/min for uncoated (p < 0.05). Hematocrit moved from a baseline level of 30 +/- 2% for coated versus 28 +/- 3% for uncoated (NS) to 28 +/- 3% for coated versus 27 +/- 5% for uncoated (NS) after 6 hours. Prebypass platelet levels of 100% in both groups moved to 84 +/- 3% for coated versus 78 +/- 23% for uncoated (NS) after 6 hours. Activated coagulation time (ACT) before bypass was 148 +/- 12 s for coated and 153 +/- 6 s for uncoated (NS). After 6 hours, ACT was 160 +/- 9 s for coated versus 152 +/- 5 s for uncoated (NS). Thrombin time before bypass was 15 +/- 2 s for coated versus 16 +/- 2 s for uncoated (NS).(ABSTRACT TRUNCATED AT 250 WORDS)
[Descending thoracic aorta: an excellent inflow source for recurrent revascularization of the lower limbs].
Although severe complications after anatomic reconstruction of the abdominal aorta are unusual, when they occur, a different strategy is required to treat the patient with success and a distinct operation is generally required for a durable favourable long term outcome. Late complications after abdominal aortic grafting include prosthetic infection, enteric erosion and graft thrombosis. Treatment by resection of the infected graft and extra-anatomic reconstruction with axillary-femoral or axillary-popliteal bypass leaves the patient with an unreliable arterial inflow for his lower extremities; in those patients who survive graft removal and extra-anatomic bypass, an alternative source of major arterial inflow should at least be discussed to effect a permanent repair. The descending thoracic aorta has been described as an ideal inflow source for definitive intracavitary conversion of extra-anatomic subcutaneous bypasses and as an occasional alternative to avoid a densely scarred abdomen or retroperitoneum. Our experience with 8 patients includes 7 in whom the aorta had been overseen below the renal arteries in a previous operation [after removal of infected graft (n = 4) and after repair of aorto-enteric fistula (n = 3)]. Our technique of primary extra-anatomic reconstruction consists of a right-sided axillo-femoral (-popliteal) bypass with femoro-femoral crossing graft. This method avoids tunneling an extra-anatomic graft in the left thoraco-abdominal region, thus facilitating the definitive repair. Preoperative radiographic evaluation of inflow and outflow details is essential in these complex cases.(ABSTRACT TRUNCATED AT 250 WORDS)
[Type B aortic dissections: surgical technique and results].
Between 1978 and 1992, 70 patients were operated for type B aortic dissection (tear in the descending aorta without involvement of the ascending aorta). 15/70 (21%) patients had an acute dissection (onset of symptoms < 24 h), 19/70 (27%) a subacute dissection (onset of symptoms < 14 days), and 36/70 (51) a chronic dissection (onset of symptoms > 14 days). The indications for surgery in cases of acute dissection were: hematothorax, oliguria, leg ischemia and persistent pain. Persistent hypertension was an additional indication in cases of subacute dissection. In large majority (93%) of chronic dissections the indication for surgery was enlarged aortic diameter. In 86% (60/70) graft replacement of the aorta was performed, in 6% (4/70) extra-anatomic bypass, in 3% (2/70) fenestration, in 3% (2/70) thrombendarterectomy, in 3% (2/70). The overall mortality was 17% (12/70); 27% of acute dissection, 26% for subacute dissection, and 8% for chronic dissection. The morbidity for acute dissection was 73%, of subacute dissection 43%, and of chronic dissection 12%. The most frequent complications were: leg ischemia (8 patients), renal failure (4 patients), paraparesis (4 patients) and sepsis (2 patients). No paraparesis was encountered in surgery of the chronic dissection. Conservative treatment was tried in all acute B-dissections, with surgical therapy being reserved for complications of the dissection, such as rupture, such as rupture, risk of rupture (hematothorax, large aortic diameter resp. expansion, persistent hypertension, persistent pain) or ischemia of distal vascular beds. Long-term survival for chronic type B dissections is good. Strong control of risk factors (hypertension) is essential.
[Hemodynamic properties of the hemopump].
The hemopump HP 31 is an improved version of a catheter-mounted, transvalvular, left ventricular assist device, which can be placed into the left ventricle through the ascending aorta. The purpose of this study was to examine the influence of hematocrit and afterload on the pump flow. The hemopump was tested using a flow bench model filled with heparinized bovine blood. The measurements were performed at four various hematocrit values: 16%, 24%, 32%, and 40%. The pump flow was measured at each hematocrit value under increasing afterload pressures (40-120 mm Hg), by all pump speed levels (n = 7). The average pump flow at highest pump speed and lowest afterload was 5.1 +/- 0.3 l/min (mean +/- standard deviation). The influence of afterload on the pump flow was statistically significant (p < 0.001). The highest afterload pressure of 120 mm Hg caused a reduction in pump flow of 24 +/- 5%. The alterations of hematocrit values caused no statistically significant influence on the pump flow (p = 0.72). The results of our study enabled the construction of the nomogram for the in vivo determination of the pump flow. The in vivo performances of the hemopump can be improved through the afterload reduction, especially in the weaning phase of treatment. The oxygen delivery can be improved through the increase in hematocrit values without significant impairment of the pump flow.
[Do resorbable suture materials permit safe vascular anastomoses?].
Vascular surgery in growing organisms is still problematic. Especially in surgical therapy of coarctation of the aorta, high restenose rates are documented if non-absorbable polypropylene and running suture technique ist used. Theoretically, absorbable suture material allows a running suture technique with less restenose rates. Our study compares absorbable (polyglyconat and polydioxanon) with non-absorbable (polypropylene) suture material for repair of aorta in growing dogs. Anastomoses performed with absorbable suture material show after one year very good functional results without any local complications. In conclusion we can say that absorbable suture material allows formation of safety vascular anastomoses and doesn't impair growth of anastomoses.
Echo-free perfused spaces: a current postoperative finding after homograft replacement of the aortic valve.
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Evaluation of phospholipidic surface coatings ex-vivo.
To evaluate the thromboresistant properties of phospholipidic surface coatings mimicking the lipid surface of blood cells, we studied four different types of phospholipids bound onto PVC tubings in comparison to uncoated as well as heparin bonded controls. The samples analyzed included diacetylenic phospholipid coated as a monomeric treatment (A), diacetylenic phospholipid polymerised prior to being coated (B), and two types of polymeric phospholipids made using methacrylate containing monomers (C and D). A bovine (bodyweight 67 +/- 3 kg) left heart bypass model (pump flow 3.2 +/- 0.1 l/min) was selected and the surfaces were exposed to the blood stream up to 360 min without systemic heparinization. Thereafter another set of samples was exposed to stagnant blood over 20 min. Besides hemodynamic, hematologic and biochemical analyses, the macroscopic appearance of 119 blood exposed surface samples was graded semiquantitatively on a scale of 0 to 10: no macroscopic deposits = grade 0, 1 spot (1 mm diameter) = grade 1, 2 spots = grade 2, 5 or more spots = grade 5, up to 10% of the surface covered with clots = grade 6, 100% covered = grade 10 (P < 0.05 = *): mean grade of deposits was 0.0 +/- 0.0 for segments perfused and 0.0 +/- 0.0 for segments exposed to stagnant blood with surfaces exposing to the blood either heparin, phospholipid A, or phospholipid B (NS). Phospholipids C and D were graded 0.0 +/- 0.0 if perfused and 0.7 +/- 1.2 if exposed to stagnant blood.(ABSTRACT TRUNCATED AT 250 WORDS)
[Occlusion of the distal aorta].
Between 1984 and 1992, 79 patients were operated for occlusion of the infrarenal abdominal aorta. 12/79 (15%) of the patients underwent emergency procedure for an acute Leriche syndrome. 67/79 (85%) of the patients with a chronic occlusion were treated electively. The surgical management includes in our series in 57/79 (72%) cases aortoiliac or aortofemoral prosthetic bypass, in 11/79 (14%) cases aortoiliac endarterectomy, in 6/79 (8%) cases embolectomy and in 5/79 (6%) extraanatomical axillofemoral bypass. For chronic total occlusion of the aorta the most common procedure was prosthetic bypass in anatomical position. For emergency cases embolectomy was performed in 42%. Early morbidity rate was 26% (21/79). The most frequent complications were thromboembolic events in 7 patients, myocardial infarction in 4 patients and renal insufficiency in 4 cases. The 30-day mortality 2.5% (2/79); the cause in both cases myocardial infarction. For atherosclerotic occlusive disease of the infrarenal abdominal aorta the prosthetic bypass is the first-choice surgical procedure. For embolic occlusions and for risk patients other less burdening procedures are available.
Postoperative diaphragmatic hernia after use of the right gastroepiploic artery for coronary artery bypass grafting.
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Myocardial ischemia caused by postoperative internal thoracic artery steal.
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