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Biomedical subjects

M I Turina

Publications and source records attributed to M I Turina.

At least 19 recordsLinked to original sources
PubMed1996

Heart transplantation with bicaval anastomoses after a maze operation.

A 49-year-old man had progressive low cardiac output syndrome after mitral valve repair combined with a maze operation. A biventricular assist device was implanted and, finally, emergency orthotopic heart transplantation was performed. The multiple incisions, especially right atrial incisions, were successfully avoided by heart transplantation with bicaval anastomoses.

Anastomosis, Surgical↗
PubMed1996

Pressure gradients across bileaflet aortic valves by direct measurement and echocardiography.

BACKGROUND: Pressure gradients calculated from echo-cardiography after aortic valve replacement are commonly much higher than would be expected from in vitro measurements. METHODS: The mean, peak-to-peak, and maximal gradients across bileaflet aortic prostheses (St. Jude Medical) were measured invasively in 52 patients at high and low heart rate, cardiac index, and stroke volume. One week after operation the gradients were calculated from a standard transthoracic echocardiogram (delta p = 4v2(2)). In a second study 3 to 12 months later, gradients were calculated using the standard, simplified Bernoulli equation, and with the equation considering subvalvular flow velocities (delta p = 4(v2(2-)v1(2)). Invasive and echocardiographic measurements were matched and compared. RESULTS: Invasively measured mean gradients for 21 to 29-mm valves ranged from 7.4 +/- 4.9 to 4.3 +/- 1.6 mm Hg at systolic flow rates from 11.3 +/- 0.7 to 16.2 +/- 1.8 L.min-1.m-2. Mean echocardiographic gradients were 15.1 +/- 4.5 to 7.5 +/- 2.2 mm Hg (p < 0.001) with the standard method, and 10.5 +/- 1.9 to 5.6 +/- 1.5 mm Hg when considering the subvalvular flow velocity (p < 0.001). CONCLUSIONS: Mean gradients across bileaflet prostheses are generally low, even in small valves and with high systolic flow. The correlation of the invasive in vivo with in vitro gradients is good. Standard echocardiography overestimates gradients across bileaflet heart valves and high gradients are not due to valve dysfunction. Gradients obtained by echocardiography considering the subvalvular flow velocity correlate better to invasively measured and in vitro gradients.

Adult↗
PubMed1996

Early in vivo experience with the Hemodynamic Plus St. Jude Medical heart valves in patients with narrowed aortic annulus.

BACKGROUND: Small aortic orifice primarily resulted in heart prosthesis mismatch in a significant number of patients. The Hemodynamic Plus (HP) series of St. Jude Medical heart valves represents an interesting innovation, allowing a larger valve orifice area with an equivalent tissue annulus diameter. METHODS: Hemodynamic characteristics of the 21-mm HP St. Jude Medical valve were prospectively compared with those of the standard 21-mm and 23-mm St. Jude Medical valves in three groups of 22 patients. Patients were selected from a database to be rigorously matched for age, sex, body surface area, functional class, underlying lesion, native valve opening area, left ventricular function, and preoperative peak and mean valve gradients. Postoperative evaluation (follow-up ranging from 3 to 24 months; mean, 11.5 months) included clinical examination and echocardiographic studies. RESULTS: There was no operative mortality or significant perioperative complications. Short-term clinical follow-up was marked by a complete absence of valve-related complications. Presently, all but 1 patient in the 21-mm HP group and 2 in the 21-mm standard group are in New York Heart Association functional class I. Doppler echocardiography-derived mean and maximal pressure gradients were significantly lower in the 21-mm HP group (8.1 +/- 1.9 and 16.4 +/- 3.4 mm Hg) than in the 21-mm standard group (13.4 +/- 3.9 and 21.2 +/- 4.3 mm Hg; p = 0.002 and p = 0.0004, respectively), confirming the better hemodynamic performance already described in in vitro studies. Pressure gradients did not differ significantly between the 21-mm HP and the 23-mm standard groups. The 21-mm HP valve demonstrated the highest performance index; 0.66 +/- 0.08, compared with 0.49 +/- 0.09 for the 21-mm standard valve (p < 0.001) and 0.59 +/- 0.07 for the 23-mm standard valve (p < 0.001). CONCLUSIONS: In vivo hemodynamic performance of the 21-mm HP valve corresponds closely to that of the 23-mm standard valve and is substantially better than that of the 21-mm standard valve. The 21-mm HP St. Jude Medical valve demonstrates excellent hemodynamic characteristics and can be recommended in normal-sized adult patients with narrow aortic root. This valve will minimize the need for aortic annulus enlargement.

Adult↗
PubMed1996

Aortic valve preservation in acute type A dissection: is it sound?

A series of 200 consecutive patients with acute Stanford type A dissection (157 men, 78%; 43 women, 22%) was analyzed to assess the validity of aortic valve preservation or repair. Indication for the operation in most cases was based on echocardiographic examination alone, to reduce the delay. In the majority of patients (111/200, 56%) the aortic valve was preserved or repaired if necessary. Aortic root replacement with a composite graft was performed in 66 of 200 patients (33%), mainly because of an enlarged aortic anulus and sinus. Replacement of the aortic valve and the supracoronary ascending aorta was performed in 23 of 200 patients (12%) with a diseased aortic valve (e.g., bicuspid valve) but an acceptable aortic sinus. Follow-up totaled 656 patient-years (maximum 14 years). Actuarial analyses as a function of type of repair and type of aortic valve provided the following probabilities plus or minus errors (95%): overall survival of the 200 patients was 78.3% +/- 2.9% after 30 days, 74.95% +/- 3.1% after 1 year, 67.9% +/- 3.6% after 5 years, and 48.5% +/- 6.1% after 10 years. Actuarial probability of freedom from reoperation for valve failure in the complete series was calculated as 100.0% +/- 0.0% after 30 days, 99.3% +/- 0.7% after 1 year, 97.5% +/- 1.5% after 5 years, and 95.1% +/- 2.8% after 10 years. During long-term follow-up, there was no significant difference among groups with regard to structural deterioration, valve thrombosis, thromboembolic complications, anticoagulant-induced hemorrhage, and endocarditis. Freedom from valve failure and valve-related complications are similar for preserved, repaired, mechanical, and biologic valves. Valve-related reoperations are rare during at least 5 years of follow-up. Hence preservation or repair of the aortic valve can be recommended in the majority of patients with acute type A dissection.

Actuarial Analysis↗
PubMed1996

Simplified, controlled limb reperfusion and simultaneous revascularization for acute aortic occlusion.

A 62-year old patient was admitted with a 24-hour history of ischemia in both legs caused by acute distal aortic occlusion and had had a total loss of sensitivity and motor function for 8 hours. Preoperative serum creatine phosphokinase level was 10,900 IU/ml. During aortofemoral reconstruction, both limbs were reperfused with a potassium-free, blood-cardioplegia-like perfusate. Fasciotomies were not necessary. After operation, maximal serum creatine phosphokinase levels remained below 10,000 IU/ml. Limb sensitivity and motor function were normal. Even for prolonged acute aortoiliac occlusion, a simplified controlled limb-reperfusion may preserve skeletal muscle and nerve function and prevent local and systemic complications caused by reperfusion damage.

Aortic Diseases↗
PubMed1996

Dorsocranial liver resection and direct hepatoatrial anastomosis for hepatic venous outflow obstruction: long-term outcome and functional results.

OBJECTIVES: The management of hepatic venous outflow obstruction, usually known as Budd-Chiari syndrome, remains complex despite a variety of treatments. METHODS: We present the results from 16 patients with Budd-Chiari syndrome who underwent dorsocranial liver resection and direct hepatoatrial anastomosis over a 10-yr period. The inferior caval vein was occluded in 10 patients. RESULTS: Operative mortality was 12.5% (2/16). During a mean follow-up of 7.2 yr, three patients required reoperation, two of whom had veno-occlusive disease. The late mortality was 14% (2/14). Clinical status improved in terms of: abdominal pain, 81 versus 14%; lower limb edema, 56 versus 14%; hematemesis, 19% versus 0%; hepatomegaly, 94 versus 36%; esophageal varices, 56 versus 7%; splenomegaly, 56 versus 21%; and ascites, 87 versus 29%. Mean serum bilirubin (micromol/l) fell from 40.2 to 27.1 (p = 0.005), and serum albumin remained unchanged. A patent hepatoatrial anastomosis was demonstrated in 10/12 survivors. The actuarial survival rate was 74.2% at 5 and 10 yr. CONCLUSIONS: Thus, in patients with outflow obstruction of the major hepatic veins, transcaval dorsocranial liver resection and direct hepatoatrial anastomosis recreate an adequate hepatic runoff. Moreover, this procedure is appropriate for patients with occlusion of the inferior caval vein, obviates or defers the need for liver transplantation, and prevents recurrence of thrombosis.

Adolescent↗
PubMed1995

[The maze operation: surgical therapy of chronic atrial fibrillation].

The maze operation is a newly developed surgical procedure for patients with chronic atrial fibrillation. Between may 1993 and october 1994, 11 patients underwent mitral valve surgery combined with the maze procedure, 10 for chronic, medically refractory, symptomatic atrial fibrillation and 1 for intermittent, symptomatic atrial flutter. In one patient, a double aorto-coronary venous bypass was added. The operative mortality was 9%: one patient died on the 7th postoperative day from a perioperative cerebrovascular accident. Postoperatively, electrophysiological and stress testing as well as transthoracic or transesophageal echocardiography (TTE; TEE) were performed. All patients were in sinus rhythm. Left and right atrial contractions were analyzed by TTE/TEE and the atrial transport function was documented in each patient. The postoperative exercise stress test revealed slight sinus-node incompetence. After a mean follow-up time of 10.4 +/- 5.4 months (1 to 16 months) all surviving patients are free from atrial fibrillation or flutter and without need for medication. The maze operation, which we performed for the first time in connection with mitral valve surgery, is a successful treatment for chronic, medically refractory atrial fibrillation and intermittent, symptomatic atrial flutter. This procedure provides a sinus rhythm with atrioventricular synchrony, restores the atrial transport function and obviates the need for antiarrhythmic drugs. Long-term anticoagulation appears unnecessary.

Adult↗
PubMed1995

Normothermia versus hypothermia during cardiopulmonary bypass: a randomized, controlled trial.

To evaluate the influence of perfusion temperature on systemic effects of cardiopulmonary bypass (CPB), 30 patients undergoing elective coronary artery bypass grafting were randomly assigned to either normothermic (warm, n = 14, 36 degrees C) or hypothermic (cold, n = 16, 28 degrees C) CPB. Serial hemodynamic measurements and blood samples were obtained before, during and after the CPB procedure. During CPB, there were no differences between both groups in the need for vasopressors (norepinephrine, phenylephrine), urinary output, or fluid balance. In the early postoperative period, normothermic CPB patients had significantly lower systemic vascular resistance and higher cardiac index measurements (mean +/- standard error: systemic vascular resistance, 880 +/- 27 versus 1,060 +/- 57 dyne.s.cm-5, p = 0.025; cardiac index, 3.6 +/- 0.1 versus 2.9 +/- 0.1 L.min-1.m-2, p = 0.01) without differences in the administration of vasoactive drugs. Blood loss was significantly higher in patients after hypothermic CPB (median [range] body surface area: 370 [180-560] versus 490 [280-2,120] mL/m2, p = 0.0006), with a greater need for transfusion of erythrocytes and fresh frozen plasma. Plasma levels of tumor necrosis factor and soluble tumor necrosis factor receptors increased during and after CPB, independent of perfusion temperature. This study suggests a significant influence of CPB temperature and respective perfusion management on postoperative hemodynamics and blood loss. Normothermic CPB is not associated with additional systemic adverse effects.

Blood Loss, Surgical↗
PubMed1995

Prevention of residual ventricular septal defects with fibrin sealant.

BACKGROUND: Modern echocardiography now allows for the detection of a substantial number of residual ventricular septal defects (VSDs) after surgical patch repair that remained hidden in the past. Mostly without hemodynamic significance, residual VSDs may have clinical consequences (progressive dehiscence, hemolysis, prophylactic antibiotic treatment, endocarditis). To reduce the number and size of residual VSDs we performed an experimental and a clinical study. METHODS: (1) In an experimental setup, burst pressure of 60 fibrin glue-sealed defects (calibrated between 1.0 and 5.0 mm in diameter) was determined using a computerized recording system and pressure loads up to 500 mm Hg. (2) In a prospective clinical trial with blinded postoperative echocardiographic controls VSD closure was performed in 36 consecutive patients (age, 37 +/- 40 months; range, 4 to 134 months) using a polytetrafluoroethylene patch and running sutures reinforced with pledgets (22 of 36 patients) or sealed with fibrin glue (14 of 36 patients) in accordance to the surgeon's preference. RESULTS: (1) Experimentally, mean pressure load achieved was more than 500 +/- 0 mm Hg for 1.0-mm defects, 413 +/- 52 mm Hg for 2.5-mm defects, 363 +/- 58 mm Hg for 4.0-mm defects, and 313 +/- 48 mm Hg for 5.0-mm defects (r 0.873, p < 0.001). (2) Clinically, all patients survived. Residual VSDs at echocardiography were observed in 16 of 22 patients (72%) for reinforced versus 5 of 14 patients (36%) for sealed with fibrin glue (p < 0.05). Diameter of residual VSDs accounted for 1.3 +/- 1.2 mm for reinforced versus 0.3 +/- 0.4 mm for sealed with fibrin glue (p < 0.01). Hemodynamically significant residual VSDs were fond in 2 of 22 patients (9%) for reinforced versus 0 of 14 patients (0%) for sealed with fibrin glue (p = not significant). CONCLUSIONS: Small defects sealed with fibrin glue resist physiologic pressure load. Fibrin glue sealing of prosthetic patches during intracardiac VSD repair allows for significant reduction of number and size of residual VSDs. Improved long-term outcome can be expected.

Anti-Bacterial Agents↗
PubMed1995

Embolization of biologic glue during repair of aortic dissection.

A 72-year-old patient was operated on because of an acute type A aortic dissection with the primary entry located in the aortic arch and with retrograde involvement of the ascending aorta. Complete replacement of the aortic arch and the ascending aorta was performed after the dissected aortic layers had been readapted and sealed with gelatin-resorcin-formaldehyde biologic glue. Postoperative neurologic status was judged to be normal. The patient died 3 weeks postoperatively of septic shock. Postmortem examination of the brain revealed several small lesions, and microscopy showed very small particles of polymerized glue in the afferent vessels of ischemic cerebral and meningeal regions.

Aged↗
PubMed1995

Modified operation technique for orthotopic heart transplantation.

Atrioventricular (AV) valve dysfunction with tricuspid regurgitation is a common finding after orthotopic heart transplantation (HTx). In 20 patients the heart transplantation was performed with bicaval anastomoses and the results were compared to the precedent 20 patients operated with the standard technique. The right atrium of the recipient was completely removed and the caval anastomoses were performed on the beating heart during reperfusion. Using an interrupted suture line, no stenoses at the venous anastomoses were seen as known from the early implantation technique in heart-lung transplantation. Due to a more stable sinus rhythm only 15% of the patients in the bicaval group needed prolonged pacing (> 30 min) versus 55% (P < 0.01) in the group with standard operation. One to 3 months after surgery the transthoracic echocardiographic evaluation of the AV valve function showed tricuspid valve regurgitation (TVR) in 20% of the patients with bicaval anastomoses versus 75% with a right atrial anastomosis (P < 0.001). Tricuspid valve regurgitation during the first 2 weeks (in 31% of recipients with bicaval and in 70% with atrial anastomoses) improved in all recipients with bicaval anastomoses and in 14% of the recipients with atrial anastomosis. The modification of the operation technique did not result in significantly longer bypass time (75 +/- 14 versus 68 +/- 14 min) and ischemia time (44 +/- 12 versus 41 +/- 9 min with local organ procurement and 111 +/- 24 versus 101 +/- 19 min with distant organ procurement). The AV valve function and the postoperative rhythm after orthotopic HTx can be improved by implanting the heart with bicaval anastomoses.

Adult↗
PubMed1995

Acute lung injury during cardiopulmonary bypass. Are the neutrophils responsible?

To test the hypothesis that acute lung injury during cardiopulmonary bypass (CPB) is related to the activation of neutrophils and the body temperature during bypass, we determined the differential WBC count, plasma elastase concentrations, and lung function before, during, and after CPB in 38 patients undergoing elective coronary artery bypass surgery. The patients were randomly assigned to receive either normothermic (n = 19, rectal temperature: 35.9 +/- 0.1 degrees C, mean +/- SE) or hypothermic (n = 19, 29.2 +/- 0.5 degrees C) CPB. The cellular response to the extracorporeal circulation was significantly delayed in the hypothermic group with a later onset of neutrophilia and a later increase in plasma elastase levels during bypass. Lung function deteriorated significantly after CPB as assessed by respiratory index, alveolar-arterial oxygen gradient, and intrapulmonary shunt, independent of bypass temperature. There was a positive correlation between peak elastase concentrations and postoperative respiratory index as well as intrapulmonary shunt (R2 = 0.5, p = 0.002 and R2 = 0.45, p = 0.003, respectively). Besides peak plasma elastase levels, multiple regression revealed no significant influence of other independent factors on postoperative lung dysfunction in our patients.

Body Temperature↗
PubMed1994

Quantitative gas transfer of an intravascular oxygenator.

The intravascular oxygenator is a newly developed device for intracaval gas exchange in critically ill patients with respiratory failure. In an experimental ex vivo model, performance characteristics of the intravascular oxygenator/carbon dioxide removal device were studied. With a mean hemoglobin concentration of 6.2 +/- 1.9 g/dL (mean +/- standard deviation), total O2 transfer was 21.8 +/- 4.8 mL/min at a blood flow of 1 L/min, 37.0 +/- 12.6 mL/min at 2 L/min, at 2 L/min, and 47.5 +/- 16.7 mL/min at 3 L/min. Total CO2 transfer was 27.3 +/- 6.6 mL/min at a blood flow of 1 L/min, 38.6 +/- 8.9 mL/min at 2 L/min, and 40.4 +/- 9.3 mL/min at 3 L/min. In contrast to total gas transfer, O2/CO2 transfer rates (mL/L) diminished significantly with increasing blood flow. In addition, there was a negative correlation between O2 transfer rate and venous O2 partial pressure (r = -0.73; p < 0.0001), a positive correlation between CO2 transfer rate and venous CO2 partial pressure (r = 0.65; p < 0.0001), and a positive correlation between O2 and CO2 transfer rates and blood hemoglobin level (r = 0.57 [p < 0.01] and r = 0.70 [p < 0.01], respectively). These results demonstrate that the behavior of the intravascular hollow-fiber oxygenator is similar to that of the classic membrane oxygenator used for cardiopulmonary bypass: total gas transfer correlates directly with blood flow and venous CO2 partial pressure and indirectly with venous O2 partial pressure. The O2 and CO2 transfer rates increase significantly with increasing hemoglobin content of the blood.

Animals↗
PubMed1994

Treatment of acute pulmonary hypertension with inhaled nitric oxide.

We examined the effectiveness of inhaled nitric oxide (NO) as a selective pulmonary vasodilator in acute pulmonary hypertension in an in vivo canine model with fixed cardiac output. In 5 dogs, total right heart bypass was instituted, and pulmonary hypertension was induced by infusion of the thromboxane analogue U-46619. During U-46619 infusion, NO was administered at 10 and 40 ppm for 5 minutes followed by breathing of the oxygen mixture without NO. Pump flow was held constant during the experiment. Infusion of the thromboxane analogue resulted in an increase in pulmonary vascular resistance and systemic vascular resistance from 147 +/- 83 to 740 +/- 126 dyne.s.cm-5 and from 1,720 +/- 113 to 2,407 +/- 232 dyne.s.cm-5, respectively. During inhalation of 10 ppm NO, pulmonary vascular resistance significantly decreased to 613 +/- 55 dyne.s.cm-5 (p < 0.05) and further decreased to 527 +/- 163 dyne.s.cm-5 with 40 ppm NO inhalation (p < 0.05). Systemic vascular resistance did not change during NO treatment (2,300 +/- 70 dyne.s.cm-5 during 40 ppm NO). There was no increase in intrapulmonary shunting or methemoglobin levels during NO inhalation. In this setting, with a constant cardiac output throughout the experiment, NO acted as a selective pulmonary vasodilator without altering systemic vascular resistance. However, induced pulmonary vasoconstriction was only partially reversed by NO inhalation.

Acute Disease↗