Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “HEART VALVE DISEASES”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 415 records · Page 23Linked to original sources
PubMed1996

Magnetic resonance imaging of blood velocity distribution around St. Jude medical aortic valves in patients.

BACKGROUND AND AIMS OF THE STUDY: Complications after replacement of diseased heart valves with mechanical prostheses may be related to fluid dynamic disturbances. Magnetic resonance velocity mapping may allow quantitative, non-invasive, serial assessment of the blood velocity distribution around prosthetic heart valves in patients. MATERIAL AND METHODS: Velocity mapping was performed in six patients with aortic St. Jude Medical valves. Axial velocity components were measured at three positions near the valve and correlated with earlier in vitro results and with earlier invasive measurements. RESULTS: The velocity profiles downstream of the valve prostheses reflected the valve design and thus confirmed previous findings. In the one diameter downstream position blood flow velocities accelerated initially through the lateral orifices of the valve. Later in the acceleration phase the velocity profile became skewed and the antegrade velocity components increased in the part of the vessel corresponding to the central slit of the valve. Retrograde velocities occurred in part of the lateral orifice regions. CONCLUSIONS: MR velocity mapping provides valuable information on velocity fields around prosthetic bileaflet aortic valves. The velocity fields from the present study disclose qualitative similarity to those previously obtained. The present study, however, suggests a more skewed velocity profile than predicted from former studies. More extensive studies on larger patient groups should be performed, also with other valve types in order to establish a bank of reference data.

Adult↗
PubMed1997

Treating the non-electrical risks of atrial fibrillation.

Atrial fibrillation is a common condition and carries a risk of thromboembolism. There is general acceptance that those patients with atrial fibrillation secondary to valvular (and in particular mitral) heart disease or following valve replacement require anticoagulation. Since patients with non-valvular causes of atrial fibrillation are a more heterogeneous group, the indications for anticoagulation have been less clear. A number of benchmark studies clearly indicate that the risk of stroke can be reduced by up to 70% in those treated with warfarin, but only by a variable 30% with aspirin. Problems with interpretation of the results of these studies relate to the younger age range included and a low recruitment rate, leading to a possible under-estimate of the bleeding risk. Subgroup analysis provides risk stratification for patients with non-valvular atrial fibrillation so that those with three or more of any of the five following risk factors: congestive heart failure, hypertension, previous stroke, left atrial enlargement or left ventricular hypertrophy, have an 18% chance of new thromboembolic events, whereas this falls to one third of this with only one or two risk factors, and 1% with none. Those with so-called lone atrial fibrillation aged < 60 years have a very low incidence of atrial fibrillation and can be considered for aspirin alone. The trials supporting in these statements are presented.

Aged↗
PubMed1991

[Prognosis of long-term results of aortic and mitral valve prosthesis by the data of treadmill test].

The treadmill test was conducted in 328 patients who underwent prosthetics of the aortic or mitral valve for rheumatic heart disease. The object of the test was evaluation of the heart pumping function according to the dynamics of the oxygen debt, pulmonary hypertension according to the pseudoanaerobic threshold, and decompensation of metabolic acidosis according to the appearance of the hypocapnic reaction. The findings were compared with the results of preoperative examination. The results of the preoperative treadmill test were found to be in accord with the probability of a positive effect of prosthetics. Depending on an increase of the critical loads level this probability rose from 2 to 87% in mitral and from 25 to 100% in aortic prosthetics. It is shown that development of lactoacidosis decompensation in addition to the heart pumping function defect significantly aggravates the late-term results of the operation.

Aortic Valve↗
PubMed2006

Extracellular matrix remodeling and organization in developing and diseased aortic valves.

Heart valve disease is an important cause of morbidity and mortality worldwide. Little is known about valve disease pathogenesis, but increasing evidence implicates a genetic basis for valve disease, suggesting a developmental origin. Although the cellular and molecular processes involved in early valvulogenesis have been well described, less is known about the regulation of valve extracellular matrix (ECM) organization and valvular interstitial cell (VIC) distribution that characterize the mature valve structure. Histochemistry, immunohistochemistry, and electron microscopy were used to examine ECM organization, VIC distribution, and cell proliferation during late valvulogenesis in chicken and mouse. In mature valves, ECM organization is conserved across species, and developmental studies demonstrate that ECM stratification begins during late embryonic cusp remodeling and continues into postnatal life. Cell proliferation decreases concomitant with ECM stratification and VIC compartmentalization. Explanted, stenotic bicuspid aortic valves (BAVs) from pediatric patients were also examined. The diseased valves exhibited disruption of the highly organized ECM and VIC distribution seen in normal valves. Cusps from diseased valves were thickened with increased and disorganized collagens and proteoglycans, decreased and fragmented elastic fibers, and cellular disarray without calcification or cell proliferation. Taken together, these studies show that normal valve development is characterized by spatiotemporal coordination of ECM organization and VIC compartmentalization and that these developmental processes are disrupted in pediatric patients with diseased BAVs.

Aging↗
PubMed1998

Preconditioning enhances myocardial protection in patients undergoing open heart surgery.

To date, ischemic preconditioning is regarded as the most powerful form of endogenous myocardial protection. For the purpose of surgical myocardial protection, a few clinical studies have investigated the effects of ischemic preconditioning in conjunction with hypothermia or blood cardioplegia during open heart surgery, but the results were controversial. We now tested the hypothesis that preconditioning improves myocardial protection in patients undergoing cold crystalloid cardioplegic arrest. 36 patients needing mitral prosthetic valve replacement for rheumatic heart disease were studied. Patients were evenly divided into two groups at random. Preconditioning was elicited by two cycles of 3 minutes ischemia by occlusion of vena cava and aortic cross-clamping followed by 2 minutes reperfusion under cardiopulmonary bypass. All hearts were arrested using 4 degrees C St. Thomas' Hospital solution before the intracardiac operative program. Myocardial protective effects were mainly assessed by electrocardiac activities, leakage of myocardial enzymes, myocardial contractility, and early postoperative recovery. The results indicated that there was a significant reduction of ST-segment shifting (ST-segment elevation, 0.07 +/- 0.02 vs 0.22 +/- 0.07 mV, p < 0.05, at 4 hours post reperfusion) and smaller release of creatine kinase-MB (87 +/- 11.5 vs 143 +/- 17.2 IU/L, p < 0.05, at 12 hours post reperfusion) in the preconditioning group. Preconditioning also enhanced myocardial contractility (dp/dtmax = 1490 +/- 75 vs 1280 +/- 88 mmHg/sec, at 30 minutes post reperfusion, p < 0.05) and promoted early postoperative recovery. The present study suggests that ischemic preconditioning reduces ischemia-reperfusion injury in human hearts even when combined with cold crystalloid cardioplegia.

Adult↗
PubMed1982

[Abnormal communications in acute bacterial endocarditis of the aortic valve].

Abnormal communications acquired during acute aortic valve bacterial endocarditis are rare but serious complications. Seven cases are reported; between the left ventricle and right atrium (3 cases), the left and right ventricles (2 cases), the aorta and right atrium (I case) and the aorta and left atrium (I case). The usual causal organisms is a staphylococcus (4 out of 7). The diagnosis is suspected on the development of atrio-ventricular block, a parasystolic murmur and sudden severe cardiac failure, but can only be confirmed by catheterisation and angiocardiography (impractical in our patients because of their poor condition). Echocardiography is of great diagnostic value. Surgical cure involves a double approach aortotomy and opening the other chamber involved), with extensive excision of the infected tissues, closure of the perforation, reconstruction of the aortic ring and implantation of an aortic valve prosthesis. The extent of the anatomical lesions affects the choice of the mode of reparation. There was no operative mortality in our series but two patients have persistent diastolic murmurs due to perivalvular leaks. In one case, recurrent infection led to the implantation of an apico-aortic tube with a fatal outcome.

Adult↗
PubMed1990

[The value of using transesophageal echocardiographic Doppler color flow imaging in patients undergoing cardiac valvular surgery].

To assess the value of intraoperative transesophageal echocardiographical Doppler color flow imaging (TEE-DCFI) during cardiac valvular surgery, 85 consecutive patients with 102 diseased valves for surgery were studied with pre-and post-operative TEE-DCFI. There were 34 women and 51 men with an age range of 15 to 55 years (mean age, 34.91 +/- 9.33 years). The etiology of valve lesion was rheumatic in 57 (AV 10, MV 47), prolapse in 9 (AV 2, MV 7), endocarditis in 21 (AV 12, MV 3, PV 2, prosthetic infection 4), prosthetic dysfunction in 14 (AV 5, MV 9), congenital in 1 (TV). Preoperative TEE-DCFI findings were helpful either in completing with some new information or changing the operation plan in 29 valves (28.43%) including abscess at aortic root in 1, perforation of aortic valve in 2, perforation of mitral valve leaflets in 5 patients with aortic valvular endocarditis, regurgitation or perivalvular leak of prosthetic valve in 4 MVs and 4AVs, left atrial thrombus detected in 8 and excluded in 3 patients with MV disease, small calcified vegetation on PV with normal valve function in 2 patients with congenital heart disease. Postoperative TEE-DCFI evaluation was performed in 53 patients with 70 diseased valves. There was only one mild regurgitation of mitral bioprosthesis and one mild perivalvular leak of aortic prosthesis detected among 40 replaced prosthetic valves. Of 30 valves repaired 23 (77%) valves had trivial or mild residual regurgitation (Group A) and 7 (23%) had moderate residual regurgitation (Group B). Postoperative congestive heart failure was seen in 6 (26.09%) of Group A and 5 (71.43%) of Group B (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1996

Prevention of thromboembolic events in valvular heart disease.

Thromboembolic events are major causes of morbidity and mortality in patients with native heart valve disease and artificial heart valves. Oral anticoagulation can reduce these complications. The indication for and intensity of oral anticoagulation depends on both, the risk for thromboembolic events and the risk of hemorrhage. The indications for oral anticoagulation in the various pathological conditions are defined. Risk factor adjusted intensity of oral anticoagulation and risk factor modification are new and very important aspects in the management of these patients which may lead to a reduction in anticoagulation associated complications and an improvement in antithrombotic effectivity. Further studies to identify the optimal therapeutic ranges of anticoagulation for the individual patient are needed. Multi-centre prospective randomized studies in this field should help us to answer the still open questions including new hemostatic molecular markers to further identify patients with different risk profiles.

Anticoagulants↗