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Biomedical subjects

M Turina

Publications and source records attributed to M Turina.

At least 343 records · Page 19Linked to original sources
PubMed1989

[Enoximone as an alternative to mechanical circulatory support prior to heart transplantation].

Enoximone, a relatively new type III phosphodiesterase (PDE III) inhibitor with combined positive inotropic and vasodilating properties, was used as a pharmacological bridge to heart transplantation in a patient with severe dilatative cardiomyopathy (ejection fraction 11-13%), who developed cardiogenic shock refractory to conventional therapy with catecholamines and vasodilators. Enoximone led to an 88% increase in cardiac index (from 1.6 to 3.0 l/min.m2). Despite a noticeable rise in heart rate, stroke index increased by 57%. Systemic vascular resistance decreased by 48% without any relevant change in mean arterial pressure. Cardiac filling pressures remained high. Oxygen transport doubled and oxygen extraction ratio decreased by 10%. Apart from a decrease in arterial oxygen tension (from 15.8 to 12.8 kPa [119 to 96 mm Hg]), no other side effects were noted. Withdrawal of catecholamine therapy did not cause any relevant haemodynamic changes. Although complications arose from an uncontrolled septic state, orthotopic heart transplantation was performed with success 74 hours after initiation of enoximone therapy. As the PDE III inhibitor enoximone exerts its potent inotropic and vasodilating effects without requiring adrenergic receptor activation, it may be used as an alternative to mechanical support in patients who develop cardiogenic shock resistant to catecholamines while awaiting heart transplantation.

Adult↗
PubMed1989

[Degree of arteriosclerosis of the internal mammary artery and of the coronary arteries in 45-to-75-year-old men. An autopsy study].

In the last ten years the internal mammary artery (IMA) has, thanks to its higher patency rate, been increasingly used for revascularization of the coronary arteries in preference to the saphenous vein. However, uncertainty about atherosclerosis in the IMA has continued to be voiced, and to clarify the issue we investigated post mortem the IMA and left anterior descending (LAD) coronary artery in 48 male patients who died aged 45-75 years. Six segments of the IMA and 4 of the LAD, totalling 465 histologic cross sections, were estimated quantitatively. The result was unequivocal: the tendency to stenosing intimal sclerosis is much more marked in the coronary artery than in the IMA. The IMA is not immune to intimal thickening, but even in patients with severe coronary artery disease the degree of atherosclerosis in the IMA is not of functional relevance. This fact makes the IMA the vessel of choice for coronary bypass surgery.

Aged↗
PubMed1989

[Heart valve replacement in active infectious endocarditis].

A material of 87 patients who underwent cardiac surgery for active infective endocarditis from 1975 to 1987 is analyzed retrospectively. 91 emergency operations were performed in 19 women and 68 men with a mean age of 48 years. 72 native valves and 19 prosthetic valves were involved. Streptococci (41%) and staphylococci (27%) were the most frequent bacteriological isolates, whereas 19% of the cultures remained negative. Heart failure (52%), embolism (21%), uncontrolled infection (11%), prosthetic valve endocarditis (10%), atrioventricular block (4%) and ventricular septal defect (2%) were the indications for surgery an average of 22 days after diagnosis. 17 patients (19%) died, 9 during hospitalization from heart failure or septicemia and 8 in the later course. 16 patients required reoperation for valvular incompetence (5), paravalvular leak (4) or prosthesis infection (7). Five relapses (5.5%) and two reinfections (2.5%) were treated surgically while two reinfections responded to medical therapy alone. Postoperatively, 34 patients (39%) suffered severe complications such as neurological deficits, prosthetic valve endocarditis or anticoagulant haemorrhage. After a mean observation period of 52 months (range 1-147 months) 64 (91%) of the surviving patients were in NYHA classes I + II and 6 (9%) in NYHA classes III + IV.

Adolescent↗
PubMed1989

[Hepatic veno-occlusive disease: indication for liver transplantation?].

Since 1976 liver replacement has become a widespread and successful procedure in the management of acute or chronic Budd-Chiari syndrome. Since transcaval resection of the liver with direct hepato-atrial anastomosis provides a less formidable method of treating Budd-Chiari syndrome, we consider liver transplantation only in cases with thrombosis of central liver veins (veno-occlusive disease). Even in such a desperate situation liver transplantation can be very helpful, as documented in this report.

Adult↗
PubMed1989

Effects of ischemia, bypass surgery and past infarction on myocardial contraction, relaxation and compliance during exercise.

Abnormalities of left ventricular function during ischemia have been described in animal models and in humans. Exercise, while a physiologic means of inducing ischemia, has a complex effect on left ventricular function by itself. In addition, patients with coronary artery disease have a diversity of chronic changes in myocardial structure and function. Therefore, with use of micromanometer left ventricular pressure measurements and ventricular volumes, calculated from biplane cineangiograms, left ventricular function at rest and during exercise was studied in 57 patients. Exercise-induced ischemia produced a decrease in ejection fraction, an increase in end-systolic volume, dramatic increases in diastolic pressures and an upward shift in the diastolic pressure-volume relation. Central to these changes was abnormal myocardial contraction and relaxation, with reduced regional shortening and impaired left ventricular pressure decay. However, nonischemic areas were capable of augmented shortening, and global pressure decay did accelerate slightly. These findings demonstrate that exercise-induced adjustments in contraction and relaxation are intertwined with ischemia-related abnormalities. Exercise studies in patients after bypass surgery and in patients with scars from distant myocardial infarction were useful in clarifying confounding factors. For example, asynchrony of contraction and relaxation, and chronic changes in passive chamber properties, also compromise systolic and diastolic function during exercise. In patients with coronary artery disease without ischemia during exercise, left ventricular end-diastolic pressure, but not early diastolic pressure, increased during exercise. The increase in pressure was appropriate for a slight increase in end-diastolic volume in a ventricle with a steep pressure-volume relation. Furthermore, end-systolic volume, while maintained during exercise, was not reduced, as occurs normally.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Catheterization↗
PubMed1989

Deleterious effects of shock in internal mammary artery anastomoses.

Internal mammary arteries (IMAs) are increasingly used for coronary artery revascularization. However, spastic reactions after IMA-coronary artery anastomoses have been reported. Internal mammary artery flow and the effects of sudden hypovolemia, gradual hypovolemia, papaverine hydrochloride, nitrates, and epinephrine were evaluated in a canine model (n = 10) (body weight, 19 +/- 5 kg) without interference from coronary artery resistance by dissecting the IMA as a pedicle, calibrating the flowmeter during free IMA flow, and anastomosing the IMA to the right atrium. Sudden hypovolemia (withdrawal of 20% of circulating blood volume over 90 seconds) caused significant modifications (p less than 0.01) of the following hemodynamic variables: heart rate (+12%), right atrial pressure (-17%), pulmonary artery pressure (-20%), wedge pressure (-30%), aortic pressure (-49%), cardiac output (-33%), distal IMA pressure (-54%), and IMA flow (-85%). During hypovolemia, IMA flow could not be increased with topical application of papaverine, but baseline values were achieved after retransfusion of the withdrawn blood volume. Gradual hypovolemia and application of large doses of nitrates showed less dramatic effects, and injection of an epinephrine bolus under normovolemic conditions increased aortic pressure and IMA flow. Under sever hypovolemia, however, administration of an epinephrine bolus provoked only a minimal increase in aortic pressure and a contrasting decrease in IMA flow. We conclude that sudden, severe hypovolemia can lead to disproportionate IMA flow reduction and that pharmacological interventions are delicate under these circumstances.

Animals↗
PubMed1989

Late failure of systemic ventricle after atrial correction for transposition of great arteries.

The incidence of late systemic ventricular failure (SVF) was determined in 220 early survivors of atrial correction for transposition of great arteries (TGA), operated upon between 1964 and 1985. SVF was defined as either severe heart failure (NYHA class III or IV) or death due to the same cause, in the absence of other haemodynamic disturbances. The actuarial survival rate was 96% after 1, 94% after 5 and 87% after 10 years. SVF occurred in 16/220 patients (7.2%). SVF was more common in complex TGA (TGA + VSD or PS or both) with 11/99 patients (11%) than in simple TGA with 5/121 patients (4.1%), P less than 0.01. Actuarial freedom from SVF was 97% at 5, and 92.5% at 10 years. SVF caused 10/25 (40%) late deaths. SVF occurred from the 1st postoperative year up to 20 years after correction (average interval 6.3 years). In 1 of 2 patients a systemic atrioventricular (AV) valve annuloplasty did not improve SVF. Heart transplantation was performed in 2 patients and 1 is on the waiting list. SVF is a rare late complication of atrial correction for TGA with a constant incidence in the late course. SVF is more common in complex TGA.

Actuarial Analysis↗
PubMed1989

An improved procedure for enzymatic harvesting of highly purified canine venous endothelial cells for experimental small diameter vascular prostheses.

We developed a new device, the vein holder, to improve yield and purity of enzymatic harvests of venous endothelial cells. External jugular veins of mongrel dogs were dissected by a no-touch technique. In vitro length and circumference of the vein segments were decreased to about half of the in situ dimensions. The vein holder enabled mounting of the veins at 80% of their in situ length during endothelial cell harvesting. Trypan blue staining and scanning electron microscopic observations revealed that vein eversion as well as the new vein holder technique successfully removed the endothelium. Endothelial cell harvests by the eversion technique were, however, low and varied in size, viability, and purity. In contrast, the defined handling by the new vein holder technique regularly provided markedly increased amounts of endothelial cells. Most of the cells attached and developed cultures consisting of endothelial cells only, as shown by the uptake of DilAcLDL. Prostacyclin production of confluent cultures was similar to that of native veins. It is concluded that minimal handling, defined mounting, and prevention of overfilling the vein markedly improves endothelial cell harvests, providing greater amounts of viable and purified endothelial cells.

Animals↗
PubMed1989

Postinfarction ventricular septal defect--surgical strategies and results.

Twenty consecutive patients with postinfarction ventricular septal defect (VSD) were subjected to surgery: there were 8 females and 12 males with a mean age of 67 +/- 9 years. Nine acute patients developed cardiogenic shock, and intra-aortic balloon pump was started before surgery (with IABP). Eight acute patients showed preoperatively relatively stable hemodynamics, and surgery was feasible without previous use of the intra-aortic balloon pump (without IABP). The interval between myocardial infarction and surgery was 13 days for 17 acute cases. In the group with IABP the interval was 8 +/- 5 days versus 19 +/- 11 days in the group without IABP (p less than 0.025). VSD patch closure was performed in 20/20, resection of infarct in 10/20, transventricular approach without resection of infarct in 3/20, patch enlargement of the left ventricle in 2/20, plicature of an aneurysm in 3/20, aorto-coronary bypass in 10/20 (number of bypasses: 2.1 +/- 1.3) and mitral annuloplasty in 1/20. The perioperative 30 days mortality was 5/20 (25%) for the whole series. In the group with IABP mortality was 4/9 (44%) versus 1/8 (13%) in the group of acute patients without IABP (p less than 0.05). Mean follow-up for the 15 surviving patients was 1.7 +/- 1.0 years. Two patients died during the first year, one of them due to carcinoma. After 1 year, mean NYHA functional class was assessed 1.5 +/- 0.6. One patient showed a residual VSD which was closed surgically. Immediate closure of a postinfarction ventricular septal defect is the therapy of choice of this complication of acute myocardial infarct with a natural history showing an extremely high mortality.

Aged↗
PubMed1989

Retrograde internal mammary to coronary artery anastomoses.

In an effort to expand the utilization of the internal mammary artery (IMA) for revascularization of the distal coronary artery branches, distally pedicled retrograde internal mammary arteries (retro-IMA) were evaluated in 10 mongrel dogs with a mean weight of 38 +/- 13 kg. One IMA was transected at it's origin (retro-IMA) and compared to the contralateral IMA which was transected at the level of the 5th intercostal space. At a mean systemic pressure of 68 +/- 15 mmHg the mean pressure measured at the tip of the IMAs with antegrade flow was 63 +/- 14 mmHg in the retro-IMAs with retrograde flow (p less than 0.05; pressure ratio 0.8). With the same mean systemic pressure, mean antegrade free flow of the IMAs was assessed 97 +/- 43 ml/min versus 48 +/- 13 ml/min in the retro-IMAs with retrograde flow (p less than 0.005; flow ratio 0.5). Left retro-IMA to coronary artery anastomosis was performed in 6 animals to the distal left anterior descending (LAD) coronary artery and in 2 animals to the distal left obtuse marginal branch. Right retro-IMA to coronary artery anastomosis to the right posterior descending coronary artery was performed in 2 animals. The LAD coronary artery was ligated proximally to the retro-IMA to coronary artery anastomosis while the retro-IMA remained crossclamped. After documentation of significant ischemia (EKG, left atrial pressure), the crossclamp of the retro-IMA graft was removed. Subsequent normalisation of EKG and left atrial pressure occurred in all animals. We conclude that the canine retro-IMA delivers significant retrograde flow and discuss a possible use in humans.

Anastomosis, Surgical↗
PubMed1989

Internal-mammary coronary artery grafts: is their superiority also due to a basically intact endothelium?

The internal mammary artery (IMA) is a superior conduit for coronary artery revascularization and many factors have been suggested for explanation of this superiority. IMA and saphenous vein grafts have been systematically analysed with scanning electron microscopy (SEM) in a series of 11 patients undergoing coronary artery revascularization. At the time of implantation endothelial damage is almost absent in internal-mammary-artery (IMA) grafts; small areas of exposed subendothelial matrix may be present but are essentially non-thrombogenic as reflected by the lack of clots in these areas. In contrast the endothelium of harvested human saphenous veins (SV) shows large thrombogenic defects with exposed collagenous fibrils. The extent and deepness of the defects deteriorated in the period between removal of the vein and its attachment to the aorta. We conclude that long-term superiority of IMA grafts may also be due to the lack of primary intimal defects.

Adult↗
PubMed1989

Indications for pericardial glutaraldehyde-preserved xenograft in repair of congenital heart disease.

A glutaraldehyde-preserved equine pericardial xenograft was implanted in 370 patients between 1981 and 1987; pericardial sac closure in 320 (mainly over Dacron implants), atrial repairs in 19, arterial reconstructions in 22 (right outflow tract in 19, Konno's procedure in three), control of bleeding after surgery for thoracic aneurysms in seven, control of plasma leaking PTFE graft in one, and repair of diaphragmal agenesia in one. Overall infection rate was 3/370 (0.8%). Epicardial adhesions (12) at reoperation for orthotopical implants were graded 1.3 +/- 0.9 on a scale of 6 (0 = no adhesions, 5 = calcified or ossified adhesions) after 4 +/- 2 months. Shrinkage of xenograft occurred in 3/19 (16%) atrial repairs and lesser degree aneurysmal dilatation appeared in 1/19 (5%) reconstructions of the right outflow tract. No complications occurred in the implants without direct exposure to the blood stream. We recommend pericardial xenograft for Konno's procedure and control of bleeding. It should not be used routinely in the low pressure side.

Bioprosthesis↗
PubMed1989

Determination of the ratio of pulmonary blood flow to systemic blood flow by derivation of amplitude weighted mean velocity from continuous wave Doppler spectra.

Conventional Doppler echocardiographic techniques for the estimation of blood flow ratios depend on the precise measurement of the diameters of the aorta and the pulmonary artery and the mean blood flow velocities in these vessels. A simpler and quicker method is described, based on the calculation of the systolic time integrals of the amplitude weighted mean velocities from continuous wave Doppler spectra within the great arteries. In 30 controls the mean (2 SD) ratio of pulmonary to systemic blood flow averaged 0.952 (0.085). The results of the new technique showed a good agreement with those of quantitative dye dilution and oximetry in 16 patients with intracardiac left to right shunts.

Adolescent↗
PubMed1989

Wolff-Parkinson-White syndrome after transplantation of the heart.

The classic features of Wolff-Parkinson-White syndrome developed in a 49 year old man after he was given the heart of a donor who had had a normal electrocardiogram. The recipient showed type A pre-excitation on the surface electrocardiogram and clinically important paroxysmal supraventricular tachycardia. An electrophysiological study showed a left sided accessory pathway and dissociation between donor and recipient atrial activity during tachycardia. The arrhythmia was controlled by flecainide.

Electrocardiography↗
PubMed1989

Left ventricular myocardial structure in aortic valve disease before, intermediate, and late after aortic valve replacement.

Left ventricular biplane cineangiography, micromanometry, and endomyocardial biopsies were performed in 27 patients with aortic stenosis (AS) and in 17 patients with aortic insufficiency (AI). Twenty-three patients with AS and 15 with AI were restudied at an intermediate time (18 months after successful valve replacement), and nine patients with AS and six with AI were restudied late (70 and 62 months after surgery). Biopsy samples were evaluated for muscle fiber diameter, percent interstitial fibrosis, and volume fraction of myofibrils. In control biopsy samples obtained from five donor hearts at transplantation, these morphometric variables averaged 21.2 microns, 7.0%, and 57.2%, respectively. After surgery, mass determined by cineangiography decreased from 186 to 115 and 94 g/m2 in patients with AS and from 201 to 131 and 93 g/m2 in patients with AI. At the three studies, muscle fiber diameter was 30.9, 28.0, and 28.7 microns in patients with AS and was 31.4, 27.6, and 26.4 microns in patients with AI. Percent interstitial fibrosis was 18.2, 25.8, and 13.7% in patients with AS and was 20.4, 23.7, and 19.2% in patients with AI. Left ventricular fibrous content decreased from 34.2 to 29.8 and to 12.7 g/m2 in patients with AS and from 42.1 to 28.9 and to 18.9 g/m2 in patients with AI. Volume fraction of myofibrils was 57.7, 56.8, and 49.0% in patients with AS and was 56.8, 56.6 and 48.8% in patients with AI. Thus, the decrease of muscle mass determined by cineangiography at the intermediate time after valve replacement is mediated by regression of myocardial cellular hypertrophy in patients with AS and AI and in addition by a decrease of fibrous content in patients with AI. Late after surgery, left ventricular fibrous content also decreases in patients with AS. This late decrease associated with minor changes of end-diastolic volume may be important for improvement of increased diastolic myocardial stiffness. Even 6-7 years after valve replacement, incomplete regression of structural abnormalities of left ventricular hypertrophy still exists compared with the normal myocardium. The residually increased relative interstitial fibrosis and the small late postoperative decrease of volume fraction of myofibrils, associated with a prosthesis-related slight left ventricular pressure increase, are at the origin of a persistent systolic overload at the myofibrillar level.

Adult↗
PubMed1989

Endothelium-derived relaxing factor and protection against contractions induced by histamine and serotonin in the human internal mammary artery and in the saphenous vein.

We investigated the release of endothelium-derived relaxing factor (EDRF) in response to serotonin and histamine in the human internal mammary artery and saphenous vein. The arteries and veins were obtained intraoperatively and were suspended in organ chambers to record isometric tension. In mammary arteries, histamine (10(-8) to 3 X 10(-6) M) induced relaxations in rings with (70 +/- 5%, IC50, 6.5 +/- 0.2) but not without endothelium (p less than 0.005 for rings with compared with those without endothelium, n = 7-10). The response was inhibited by methylene blue or hemoglobin, but not meclofenamate, and, therefore, EDRF was delineated as the mediator. Because chlorpheniramine but not cimetidine inhibited the response, EDRF was released by the H1-histaminergic receptor (n = 5-8). In contrast, in saphenous veins, histamine caused only weak or absent endothelium-dependent relaxations, but contractions were enhanced in rings with endothelium (p less than 0.05, n = 6). Serotonin did not induce endothelium-dependent relaxations, but contractions were markedly greater in veins compared with arteries (p less than 0.005, n = 6). The endothelium inhibited the maximal contraction to serotonin in arteries (p less than 0.034) but not in veins. Thus, EDRF protects against contractions induced by histamine and serotonin in the mammary artery but not in the saphenous vein. This may be important for improved graft function and patency of the artery compared with that of the vein.

Endothelium, Vascular↗
PubMed1989

[Blood replacement in heart transplantation].

Transfusion of blood and blood products in orthotopic heart transplantations were analysed in a series of 31 consecutive patients operated upon between September 1985 and December 1987. Mean age of the 29 men and 2 women was 41 +/- 12 years (range: 15-63). All patients had to be assigned to NYHA functional class IV before operation and their mean left ventricular fraction was 20%. The etiologies of cardiac disease leading to transplantation in this series were: cardiomyopathy in 19/31 patients (61%), ischemic heart disease in 7/31 (23%), valvular disease in 2/31 (6%), life threatening arrythmias in 2/31 (6%) and primary cardiac tumor in 1/31 (3%). Previous cardiac surgery had been performed in 6/31 patients (19%). Full anticoagulation with coumarines was observed in 24/31 patients (77%) at the time of surgery when mean PT was 33 +/- 12% and mean hematocrit was 40 +/- 4%. Mean blood products transfusion requirements in patients receiving an orthotopic heart transplant were 24.2 +/- 14.7 units (range 7-67 units) during the entire hospital stay. These figures are even higher if compiled in function of the number of donors of the transfused blood products: 29.2 +/- 22.4 (range 7-105). The following mean number of blood and blood components was perfused per patient: Red cells (hematocrit 50 +/- 10%) 4.4 +/- 3.9, concentrated red cells (hematocrit 70 + 10%) 5.9 +/- 4.3, fresh frozen plasma 7.4 +/- 3.3, platelets 3.9 +/- 4.1, and others (factor 8, 9 etc) 0.6 +/- 1.6. In-hospital mortality was 1/31 patients (3%) and actuarial survival is 27/31 (87%) at 33 months of follow-up (mean 17 +/- 7 months). However, 7/27 survivors (26%) had to be treated for cytomegaly acquired during or after the heart transplantation. Therefore transfusion of cytomegaly free blood products has to be recommended.

Adult↗