PubMed Health⌕ Search

Biomedical subjects

S Wos

Publications and source records attributed to S Wos.

12 recordsLinked to original sources
PubMed2004

Early regional assessment of LV mass regression and function after stentless valve replacement: comparative randomized study.

Early regional performance and hypertrophy regression after stentless aortic valve replacement are still incompletely characterized. We compared early postoperative changes of segmental thickness and function after stentless and stented aortic valve replacement as assessed by cardiac magnetic resonance (CMR). In 16 patients randomly assigned to stented (Mosaic, 8 patients) and stentless (Freestyle, 8 patients) groups, 4 parallel short-axis images at the level of the apex (slice 4), midventricle (slices 2-3), and mitral valve (slice 1) were obtained with a 1.5 T CMR scanner (Magnetom Sonata, Siemens) before and 1 month after surgery. Cine images were obtained using an echo gradient sequence. Left ventricle mass was calculated as the difference between the left ventricular end-diastolic volume at the epicardial and endocardial borders multiplied by a myocardium density factor (1.05). Each slice was divided into 8 segments (octants) from anterior (octant I-II) to septal (octant V-VIII). A total of 32 segments encompassed the entire heart. From each of these elements end diastolic thickness and systolic function (fractional thickening) were calculated. In stentless valves significant reduction of septal octant thickness on the midventricular slice was noted. There was no difference in regional systolic function-segment thickening. In stented valves no segmental thickness changes were observed. In stentless valves there was early postoperative thickness reduction of septal segments at the midventricular level. However, this finding did not coincide with changes in segmental function.

Aged↗
PubMed2002

Hemodynamic performance after stented vs stentless aortic valve replacement.

BACKGROUND: Stentless bioprostheses are anticipated to cause improved hemodynamics and increased longevity over stented bioprosthesis. We have compared echocardiographic analysis of stented bioprosthesis "Freestyle" with stented "Mosaic" bioprosthesis. Because of similar technology (0 pressure fixation, anticalcification) any differences may relate to stent. METHODS: Twenty-eight patients undergoing AVR were randomly assigned to receive either stented or stentless. Echocardiograms, by means of M-mode and Doppler were performed early, 3-6 months and 1 year postoperatively. RESULTS: The peak flow velocity was significantly lower in the stentless group, especially 1 week and 6 months after surgery. Mean transvalvular gradient dropped significantly in stentless group and did not change in stented group. EOA did not change significantly in either of groups. AoV velocity time integral was increasing in stentless group. LV mass had fallen significantly in both groups but degree of mass reduction was comparable. CONCLUSIONS: There are marked improvements of stentless valves hemodynamics. However it is not necessary equal to higher degree of LV mass reduction during 1 year follow-up.

Aortic Valve↗
PubMed2000

Comparison of retrograde vs simultaneous ante/retrograde cold blood cardioplegia.

BACKGROUND: To evaluate the homeostasis of myocardium during simultaneous continuous retrograde and antegrade cardioplegia vs retrograde continuous cardioplegia. METHODS: 40 patients who underwent elective operation of coronary arteries bypass grafting were randomly assigned to 2 groups: group one consisted of 24 patients who received retrograde continuous blood cardioplegia; group two consisted of 16 patients who received simultaneous continuous ante/retrograde cardioplegia. The following measurements were taken: acidosis, oxygen content, oxygen extraction and oxygen consumption; they were taken before and after cross-clamp releasing from coronary sinus effluent and from arterial line. Incidence of low cardiac output, ventricular fibrillation, raised cardiac enzymes and ischemic changes on ECG was noted. RESULTS: In simultaneous group such parameters as acidosis, oxygen content, oxygen extraction and myocardial oxygen consumption recovered after cross-clamping and changes of their values were respectively: 0.0005, 0.87 ml/100 ml, 0.098 and 1.4 ml/min. The same parameters didn't recovered in retrograde group and changes were respectively: 0.05 - p=0.2; 3.7 ml/100 ml - p=0.006, 0.29 p=0.006 and 7.4 ml/min - p=0.03. These changes were significant between groups. CONCLUSIONS: Metabolic viability of myocardium measured with oxygen utilisation is better preserved with simultaneous antegrade and retrograde cardioplegia.

Adult↗
PubMed1997

Internal mammary artery graft function is not affected in hypertensive patients on therapy.

Results are presented which assess the reactivity of isolated human internal mammary artery fragments from non-hypertensive and treated hypertensive patients in vitro. Material from three patient groups was examined: group I, no hypertension; group II, arterial hypertension treated with ACE inhibitors; and group III, arterial hypertension treated with nifedipine. Responses to KCl, norepinephrine and acetylcholine, as well as the influence of N(G)-monomethyl-L-arginine (L-NMMA) on the effects of norepinephrine were tested. Response to KCl was highest in group III, while the contractile reactivity to norepinephrine was depressed in group II. Relaxation after acetylcholine was enhanced in groups II and III. Incubation of vessel fragments with L-NMMA sensitized the tissue to norepinephrine in the order of potency group II>group III>group I. Internal mammary artery function as the graft, and particularly in terms of endothelial function, is not adversely affected in arterial hypertension, although proper antihypertensive treatment may be essential.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1997

Gastric tonometry as a method of visceral oxygenation monitoring in patients undergoing coronary revascularisation.

OBJECTIVE: The aim of the study was to assess gastric mucosal pH during certain parts of a major cardiac procedure (hypo- and normothermic), and then throughout the first postoperative day. METHODS: Gastric mucosal pH was measured using a tonometer, in 15 patients subjected to elective CABG procedures. The patients were also assessed haemodynamically and serum lactate concentrations were measured. RESULTS: It was found that cardiopulmonary bypass did not suppress visceral perfusion. The most critical was the period between 4th and 12th postbypass hour when a tendency towards decreased cardiac output and oxygen delivery was noted. At the same time oxygen consumption was increasing which resulted in triggering of anaerobic metabolic pathways, that was mirrored by significant rise in serum lactate levels. During this period of time the lowest, although not critical levels of gastric mucosal pH were recorded, suggesting a relative decrease in splanchnic perfusion. CONCLUSION: Extracorporeal circulation does not significantly compromise splanchnic perfusion. Tonometry is a valuable, non-invasive method of visceral oxygenation monitoring. The first postoperative day is an especially critical time for a cardiac patient--a frequent control of haemodynamic and acid-base balance parameters is absolutely mandatory.

Coronary Artery Bypass↗
PubMed1997

Comparison of retrograde versus antegrade cold blood cardioplegia: randomized trial in elective coronary artery bypass patients.

OBJECTIVE: Myocardial areas distal to complete coronary artery occlusion are poorly protected by antegrade cardioplegia. Hence, retrograde cardioplegia becomes an important adjunct in myocardial protection. An aim of the study was to compare both methods prospectively. METHODS: 158 coronary artery bypass grafting (CABG) patients were randomly assigned to two groups according to myocardial protection technique: 89 patients to group 1--retrograde cold blood cardioplegia (RCBC); and 69 patients to group 2--antegrade cold blood cardioplegia (ACBC). Preoperative parameters were similar but cross-clamp time and volume of cardioplegia needed were higher in the retrograde group. The results were assessed on the basis of: (1) clinical outcome; (2) ECG and enzymatic parameters of ischemia; (3) assessment of early systolic function by means of cardiac output (CO), stroke work index (SWI), left ventricular stroke work index (LVSWI) and right ventricular stroke work index (RVSWI) taken before, and 1 and 5 h after coming off bypass; (4) late systolic and diastolic function by echo assessment of segmental contractility of 17 segments and indexes of peak transmitral flow (TMI) taken 7 days and 6 months after operation. RESULTS: Ischemic events, inotropes and ventricular fibrillation on reperfusion were significantly more frequent in the antegrade group. Sinus rhythm at an early stage postoperatively was found more frequently in the retrograde group. All these parameters became comparable 24 h after operation. Early myocardial recovery was better in the retrograde group where intraoperative improvement in CO and SWI was significant. At the same time, SWI decreased significantly in the antegrade group. RVSWI changes were similar in both groups. There were no differences in mortality and perioperative MI. Late myocardial performance by segmental contractility and diastolic transmitral flow were similar in both groups. CONCLUSIONS: Retrograde continuous blood cardioplegia reduces ischemic injury and permits better early recovery of myocardial function. There is no difference, however, regarding long-term assessment of myocardial recovery.

Blood↗
PubMed1996

Results of mechanical prosthetic valve replacement in active valvular endocarditis.

UNLABELLED: To evaluate the results of mechanical prosthetic valve replacement for active endocarditis 71 patients were reviewed. They were treated surgically between 1988 and 1993 in our institution. Mechanical valves were used in 54 patients (group 1) and bioprosthetic valves were used in 17 patients (group 2). In terms of demographic, clinical and surgical variables prior to operation groups were statistically the same. Follow up ranged from 2-63 months averaged 21 months. This study was carried out to: asses cardiac status postoperatively and assess the rate of mortality, recurrency and reoperations. METHODS: Evaluation of cardiac status was assessed on the basis of symptoms and findings by examination, ECG, X-ray, echocardiography, and laboratory tests. Data analysis was done by means of statistical tests like: Student's "t"-test, Fisher exact test, one sided test of difference between two percentages, Kaplan Meyer survival analysis and Cox test. RESULTS: 4-year mortality was 20% in group 1 comparing to 28,6% in group 2, when early mortality were 13% in group 1 comparing to 17% in group 2. These differences were not significant. The recurrency rate was 8,5% in group 1 comparing to 28,6% in group 2 which was statistically significant (p=0.028). Especially early recurrency rates differed significantly between groups and were 4,2% in group 1 comparing to 21% in group 2 (p=0.022). The reoperations rate was 4,2% in group 1 comparing to 21% in group 2 which was statistically significant (p=0.022). Clinical status showed satisfactory values and significant improvement in both groups, slightly better after mechanical valve replacement. CONCLUSION: It is concluded that mechanical valve is recommended for valve replacement in active valvular endocarditis first of all due to low recurrency and reoperation rate.

Adult↗
PubMed1996

Surgical treatment of atrial septal aneurysm.

The atrial septal aneurysm (ASA) is a morphologic abnormality known to cause peripheral and pulmonary embolism. 28-52% patients with ASA have embolic events. However ASA -- with no other concomittant cardiac patology has rarely been reported as the indication for open heart surgery. In this work, five cases of patients operated for ASA are presented. Embolic complications with cerebral symptoms were presented in three cases. The diagnosis of ASA was established with the use of transesophageal echocardiography. The surgical correction of the defect was performed in extracorporeal circulation. The aneurysmal part of interatrial septum was excised and replaced with a pericardial patch. The postoperative course was uneventful. The patients have no new embolic events during the follow up period of one year.

Adult↗
PubMed1990

Immunodepletion in xenotransplantation.

Xenograft transplantation is perhaps the most immunologically difficult problem in transplantation today. An overwhelming hyperacute rejection reaction (HAR) occurs within minutes of organ implantation. Preformed antibodies are thought to initiate this process. We used a pig-to-dog renal xenograft transplant model and investigated methods of decreasing the severity of hyperacute rejection. Female pigs weighing 15-20 kg were used as donors. Recipients were mongrel dogs weighing 15-25 kg. Experimental dogs were all given a number of treatments of IgG depletion using an antibody removal system (Dupont-Excorim). This machine immunoadsorbs plasma against a column containing immobilized staphylococcal protein A, which is known to bind the IgG Fc receptor. An 84% reduction in the IgG levels and a 71% reduction in IgM levels was achieved. Postoperative assessment was made of urine output, time to onset of HAR, and histopathological examination of the rejected kidneys. Although cross-matches between donor lymphocytes and recipient sera remained strongly positive in the treated dogs, there was a two- to fourfold reduction in the titers. The time to onset of HAR was prolonged in the experimental group, and the urine output was increased slightly. The histopathologic changes in the experimental group generally showed signs of HAR, but of less intensity than in the nonimmunodepleted control group.

Animals↗
PubMedDate not supplied

Does simultaneous antegrade and retrograde cardioplegia improve functional recovery and myocardial homeostasis?

BACKGROUND: The purpose of our research was to evaluate the functional recovery and homeostasis of myocardium during simultaneous continuous retrograde and antegrade cardioplegia versus continuous retrograde cardioplegia. METHODS: Forty patients who underwent elective coronary artery bypass grafting (CABG) were prospectively assigned to two clinically matched groups and analyzed in respect to cardioplegia protocol. Group I consisted of 24 patients who received continuous retrograde blood cardioplegia; Group II consisted of 16 patients who received simultaneous continuous ante- and retrograde cardioplegia. Hydrogen ion release, carbon dioxide, lactate concentration oxygen content, and oxygen extraction were measured from coronary sinus effluent and from the arterial line before and after cross-clamping of the aorta. Median changes of these parameters were reported. Cardiac output was measured and left and right ventricle stroke works were calculated. Incidence of low cardiac output, ventricular fibrillation, raised cardiac enzymes, and ischemic changes on electrocardiogram (ECG) were noted. RESULTS: In the simultaneous group, oxygen content and oxygen extraction recovered well after cross-clamping. The same parameters did not recover to the same extent in the retrograde group. These changes were notable between groups. Hydrogen ion, carbon dioxide, and lactate releases were comparable between groups. Trend toward better recovery of left ventricle stroke work index was encountered in the simultaneous group. CONCLUSIONS: Viability of myocardium measured with oxygen utilization and functional recovery is better preserved with simultaneous antegrade and retrograde cardioplegia. However, there is no difference in anaerobic metabolism markers. Thus simultaneous ante- and retrograde cardioplegia is probably advantageous over retrograde alone.

Adult↗
PubMedDate not supplied

Metabolic effects of long-term arterialization of portal blood.

In nine splenectomized male dogs a splenic artery, -splenic vein shunt was made. Before splenectomy and 3, 6 and 18 months after arterialization of portal blood, different metabolic and endocrine parameters were estimated. Long-term arterialization of portal blood was followed by only insignificant increase of portal vein pressure but a significant drop of pCO2 and increase of pO2 in portal blood was recorded. Simultaneously, a significant decrease of the erythrocyte count, hematocrit value, serum cholesterol and uric acid levels, and a shortening of the T1/2 of insulin and glucagon were found. In contrast, long-term arterialization of portal blood was followed by a significant increase of serum triglycerides, alpha2-globulins, plasma renin activity, cortisol, gastrin and 25-hydroxyvitamin D, and by slight carbohydrate intolerance. No morphological abnormalities in the liver and kidney tissue were found. Data presented in this paper suggest usefulness of a splenic artery-splenic vein shunt in the treatment of some metabolic disorders and of the failing hepatocytes.

Animals↗