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At least 487 records · Page 27Linked to original sources
PubMed1985

Cardiac valve area formula for the assessment of aortic stenosis based upon evaluation of left ventricular wall stress in diastole.

We have investigated the application of an hydraulic orifice equation employing aortic valve pressure gradient derived from ventricular diastolic wall stress measurements to estimate obstructive orifice area in aortic stenosis. The expression is given by A = SV square root (D/W)/(750t), where A is the aortic valve area in cm2, SV is the stroke volume in ml, D is the left ventricular minor axis dimension in diastole, W is the left ventricular posterior wall thickness in diastole and t is the systolic ejection period in sec. Valve areas computed by this expression using diastolic wall stress measurements correspond with valve areas derived from the Gorlin formula at a level characterized by a correlation coefficient of r = 0.95 and a standard error of SE = 0.16 cm2, N = 13 for a series of catheterization studies. All the parameters that enter the new expression may be estimated by conventional echocardiographic techniques.

Aortic Valve↗
PubMed1998

Factors affecting the yield of cardiac valve allografts from living unrelated donors.

OBJECTIVE: Allografts are the valve of choice for fertile women, patients with infective endocarditis and those with small aortic roots. However, the supply of valves is problematic and widespread usage is restricted by limited availability. Allograft valves are available from cadaveric donors and from the explanted hearts of transplant recipients. Potentially, hearts from these patients could be an excellent source of usable aortic and pulmonary valves. However, little information is available on the suitability of such donors, the procurement rate of allograft valves from this source, or the factors that limit the yield of implantable valves from explanted hearts. METHOD: In order to examine some of these issues, we have carried out a retrospective study on the explanted hearts offered to the East Anglian Tissue Bank by Papworth hospital. Papworth hospital carries out approximately 90 heart and heart/lung transplants per year. Over a 2 year period, the tissue bank was offered 72 hearts from this programme. RESULTS: Of the 72 hearts offered, 58 were accepted for subsequent dissection and further examination. A total of 14 hearts were refused. The main reasons for refusal were extensive cardiectomy trauma (4 hearts) and abnormal valve morphology (four hearts). Of the 116 valves from those hearts accepted for dissection, 55 valves were rejected upon further examination. Reasons for rejection included: cardiectomy trauma (26 valves), abnormal morphology (22 valves), procurement/dissection trauma (7 valves). Of the 61 valves banked, four were subsequently rejected due to positive or incomplete microbiology. Procurement trauma fell to 0% in the last 12 months of the study but cardiectomy trauma remained constant and was related to previous cardiac surgery. Overall, the yield of implantable valves was 0.8 valves/donor. However, the yield showed considerable variation, from 1.0 valves/donor for donors diagnosed as cardiomyopathy to 0.5 valves/donor for donors with ischaemic heart disease who had undergone previous cardiac surgery. CONCLUSION: It is possible to predict the likely yield of explanted heart valves from different groups of heart transplant recipients, based on diagnosis and previous history. The yield of usable valves could be increased by avoidance of injury, both during cardiectomy and subsequent removal of the valves; this is achievable through appropriate training.

Adolescent↗
PubMed1990

Endocarditis associated with prosthetic cardiac valves.

Clinical features, microbiology, therapy and outcome of 26 episodes of prosthetic valve endocarditis occurring at Westmead Hospital from 1979 to 1989 were examined retrospectively. Presentation with a new or changed cardiac murmur was associated with early onset infection (within 12 months of prosthetic valve insertion; P = 0.0033). Corynebacteria were the commonest cause of early onset endocarditis (4 of 11 episodes) and Streptococcus viridans of late onset endocarditis (4 of 15 episodes). Nine of 11 episodes responded to antimicrobial therapy and 12 of 15 to medical-surgical therapy. There was a trend towards increased mortality in patients with early onset endocarditis presenting with a new or changed cardiac murmur (4 of 9 v. 1 of 17, P = 0.068), suggesting early surgery should be considered in this group. Analysis of antibiograms and published reports indicated that vancomycin and an aminoglycoside should be recommended as empirical therapy for endocarditis occurring 12 to 18 months after prosthetic valve insertion.

Aminoglycosides↗
PubMed2004

Changes in type B natriuretic peptide (BNP) concentrations during cardiac valve replacement.

OBJECTIVE: The aim of our study was to investigate the ability of BNP levels to reveal the immediate post-surgery cardiac function improvement. We measured the perioperative variations in BNP concentrations in patients scheduled for cardiac surgery with cardiopulmonary bypass (CPB), chronic mitral regurgitation, valvular aortic stenosis, or myocardial ischaemia. METHODS: Three groups were included: patients with coronary artery bypass graft (CABG, group I, n = 14), aortic (AVR, group II, n = 14) or mitral (MVR, group III, n = 7) valve replacement. BNP assay was performed at the induction of anesthesia, immediately after the CPB, at the arrival in the intensive care unit, 4 h, 8 h and 12 h after the arrival in ICU. RESULTS AND CONCLUSION: The occurring variation in BNP levels after the operation is an increase whatever the corrective surgery, underlying the relative lack of specificity of BNP with regard to the cardiac pathology. Besides iatrogenic cardioplegia one can supposes that cardiac surgery involves other major stimuli such as anesthesia, sternotomia, hemodynamics, post-operative that could influence in a non specific way BNP levels.

Aged↗
PubMed1975

[Reversibility or irreversibility of pulmonary function changes after cardiac surgery on insufficient or stenotic cardiac valves (author's transl)].

In 69 patients with mitral- or aortic valves disease lung function tests were made preoperatively and 2 to 4 years after cardiac surgery. We wanted to demonstrate the extent and the improvement of restriction, obstruction and disturbed diffusing capacity of the separate diseases with different severities. We found correlations between the clinical grade of the disease and the changes in lung function. In particular grade III of the mitral stenosis showed severe restriction, obstruction and disturbed diffusing capacity. Patients with mitral insufficiency III had changes of mild degree, aortic diseases were without disturbed lung function. All detected changes of lung function were irreversible and could not be influenced by postoperative hemodynamic improvements.

Aortic Valve↗