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PubMed1983

[Cardiac valve replacement and simultaneous myocardial revascularization].

Between 1974 and 1981, 84 patients underwent cardiac valve replacement and simultaneous myocardial revascularization. 77 patients had rheumatic valve disease with coexisting coronary artery disease (group I). Single valve replacement was performed in 67 patients, double valve replacement in 9 patients, and triple valve replacement in 1 patient. A second group consisted of 7 patients with severe coronary artery disease: in 6 of them papillary muscle necrosis necessitated mitral valve replacement, and in 1 patient hemodynamic reasons made aortic valve replacement necessary. The mean number of coronary artery bypass grafts performed was 1.7 in group I and 2.4 in group II. 56 patients were classified as NYHA grade III, 28 as grade IV. 8 patients (9.4%) died within 32 days after operation (7 from group I, 1 from group II). Follow-up averaged 20 months. There were 3 late deaths; 35 of the survivors underwent clinical reexamination, and all 73 completed questionnaires. Symptomatic improvement was found to be excellent: 97% of the patients examined had improved at least by one functional class. It is our impression that simultaneously performed myocardial revascularization does not substantially increase the risk of cardiac valve replacement, and yields good late results.

Adult↗
PubMed1987

Cardiac valve surgery combined with aortocoronary bypass.

An analysis of the experience obtained in combined cardiac valve and coronary artery surgery in 23 patients was performed. The dominant feature of their clinical symptomatology was valvular disease in the majority of patients, even though angina pectoris was present in 14 of them. In all patients, cardiac valve surgery was carried out together with coronary reconstruction in the form of a single to triple bypass. The procedure involved, in two cases, simultaneous removal of a left ventricular aneurysm and, in one patient, closure of a postinfarction lesion of the interventricular septum. One patient died in the postoperative period displaying signs of the low cardiac output syndrome. Long-term follow-up included 20 patients operated on. Improvement of a varying degree was observed in 19 patients.

Adult↗
PubMed1974

Cardiac valve replacement. The rationale for earlier operation.

Cardiac valve replacement (single or double) was carried out in 138 consecutive patients with valvular heart disease over a six-year period at the Wadsworth Veterans Administration Hospital. All but a few had functional class III or IV disease. Hospital mortality was 3.6 percent.Normothermia, coronary perfusion and beating of the heart were maintained throughout the procedure. All patients were followed at least one year and the average follow-up was four and a half years. The late mortality was 27 percent. Seventy-five percent of the late deaths were due to progressive cardiac disease. The mortality due to prosthetic valve dysfunction was 4 percent. Subjective evaluation of survivors revealed that a high percentage remained symptomatic. Only 50 percent of the total group of patients were significantly improved. The high incidence of late mortality and poor long-term functional results are contrasted to the low operative risk and improved reliability of prosthetic valves. The rationale of delaying operation until functional class III limitation develops is questioned. Earlier operation is recommended before irreversible myocardial hypertrophy and fibrosis develop.

Heart Valve Prosthesis↗
PubMedDate not supplied

Thrombolytic therapy for prosthetic cardiac valve thrombosis.

During 1992-93 12 patients (5 males, 7 females) with thrombosed prosthetic cardiac valves were treated with streptokinase on 13 occasions (one patient with prosthetic tricuspid valve had two thrombotic episodes). Their age ranged from 14 to 52 years (median 39). Two valves were in aortic position, six in mitral and four in tricuspid position. Eight were Bjork-Shiley prosthesis, three were Medtronic Hall valves and one was a St. Jude Valve. Timing of prosthetic valve thrombosis ranged from 3 months to 12 years after valve replacement surgery. Duration of symptoms due to valve thrombosis ranged from 1-4 months with tricuspid valve thrombosis and 1-14 days with left sided valve thrombosis. Five were in functional class II and four each were in functional class III and class IV. All patients were evaluated by echo Doppler and cine fluoroscopy. Loading dose of streptokinase was 2.5 lakh units in 4 patients and 1 lakh units in 9 patients. Maintenance infusion was at 1000 units/Kg/hour in 11 patients and 1 lakh units/hour in 2 patients. Duration of streptokinase infusion ranged from 3 hr to 38 hr. Thrombolytic therapy was successful (clinical, echo Doppler and fluoroscopy) in 12 out of 13 cases (92%). It was unsuccessful in a patient with valve at tricuspid position in whom infusion had to be stopped after 24 hour due to bleeding gums. One patient developed intracerebral bleed and expired. In conclusion streptokinase therapy is useful for prosthetic cardiac valve thrombosis.

Adolescent↗
PubMed1994

Prevalence and characteristics of intracranial microemboli signals in patients with different types of prosthetic cardiac valves.

BACKGROUND AND PURPOSE: Transcranial Doppler detection of microemboli is widely described, but there is no clear evidence of the clinical significance or nature of the embolic material in vivo. Thromboembolism is a major cause of morbidity in patients with prosthetic cardiac valves. We undertook this study to evaluate the prevalence and the acoustic characteristics of microembolic signals in three groups of patients with different prosthetic valves. METHODS: One hundred seventy-nine patients with prosthetic cardiac valves (85 Björk-Shiley, 56 Medtronic-Hall, and 38 Carpentier-Edwards) and 25 normal subjects were examined using transcranial Doppler. Monitoring time was 30 minutes over the right middle cerebral artery. RESULTS: The prevalence and numbers of embolic signals were significantly higher in patients with Björk-Shiley compared with those with Medtronic-Hall and Carpentier-Edwards valves (89% versus 50% and 53%, respectively; P < .001, chi 2; 156 [112, 204] versus 2 [1, 4] and 2 [1, 4] signals/h, respectively; median [95% nonparametric confidence interval], both P < .001, multiple comparisons, Bonferroni correction). The signal intensity was significantly higher in patients with Björk-Shiley and Medtronic-Hall valves than patients with Carpentier-Edwards valves (2435 [2345, 2527] and 2120 [1745, 2483] versus 225 [184, 287] power units, median [95% confidence interval], both P < .001). No correlation was found between embolic signal numbers and clinical parameters including history of neurological deficit, cardiac rhythm, duration of artificial valve, previous cardiac operations, or intensity of anticoagulation. Embolic signals were not detected in any of the control subjects. CONCLUSIONS: Our data showed that the prevalence, quantity, and acoustic characteristics of Doppler embolic signals differ in patients having three different types of prosthetic heart valves. However, no correlation with clinical parameters was identified.

Adult↗
PubMed1977

Universal cardiac valve holder.

A valve holder has been designed to facilitate the insertion of porcine cardiac valves. This holder allows a return to the operative technique established with the earlier generation of mechanical cardiac valves.

Animals↗
PubMed1981

Platelet and coagulation function in patients with abnormal cardiac valves treated with sulphinpyrazone.

Eight patients on warfarin with rheumatic heart disease and prosthetic cardiac valves were selected for study on the basis of persistently elevated plasma beta-thromboglobulin (beta-tg) and platelet factor 4 (PF4) concentrations. Platelet mean lifespan and fibrinogen half life were short, and positively correlated, and both were inversely related to the plasma concentration of the platelet specific proteins. Antithrombin III (ATIII) levels were also reduced. Treatment with sulphinpyrazone resulted in lengthening of both platelet and fibrinogen survival, a rise in ATIII but no change in the beta tg or PF4 concentrations. It is concluded that patients with abnormal cardiac valves and raised plasma levels of beta tg or PF4 have, despite warfarin, a consumption coagulopathy that can be inhibited by sulphinpyrazone.

Adult↗
PubMed1983

Physical, psychologic, social, and economic outcomes after cardiac valve surgery.

Eighty-nine patients receiving cardiac valve replacement or surgery consisting of valve replacement and coronary artery bypass grafts in four teaching hospitals were studied before surgery and again six months after surgery. More than 60 indicators of the quality of life were assessed. The majority of persons showed improvement in physical function, emotional states, and social activity. Of those with exertional angina or dyspnea before surgery, about two thirds were completely relieved at six months after surgery. There was a substantial reduction in number (from 31 to seven) of persons with five or more days of disability per month due to cardiac symptoms. The majority remained the same in their usual level of physical activity, most psychological traits, and attitudes and social support networks. Most previously employed persons returned to work. Improvements in the conditions of patients who had valve surgery closely paralleled those of patients who had undergone coronary artery bypass surgery in the same hospitals.

Activities of Daily Living↗
PubMed2005

Small ischemic brain lesions after cardiac valve replacement detected by diffusion-weighted magnetic resonance imaging: relation to neurocognitive function.

OBJECTIVE: Following coronary artery bypass graft surgery, some studies using magnetic resonance imaging (MRI) have demonstrated new small ischemic brain lesions in patients without apparent neurological deficits. We aimed to prospectively evaluate brain injury after cardiac valve replacement using MRI and to determine the relationship to neurocognitive function. METHODS: Thirty patients with a mean age of 64.9+/-9.8 years (range, 32-82, 12 female) receiving cardiac valve replacement (aortic valve replacement [AVR], n = 24; mitral valve replacement [MVR], n = 2; AVR and MVR, n = 2; AVR and mitral valve repair, n = 2) were investigated. Study protocol included neurological examination, comprehensive neuropsychological assessment and diffusion-weighted (DW) MRI. The investigations were performed before surgery and 5 days and 4 months after surgery. RESULTS: Postoperative DW MRI detected new focal brain lesions in 14 patients (47%). No patient revealed a focal neurological deficit. Six patients (43%) had multiple (> or = 3) lesions (range, 1-7). Lesion volume ranged from 50-500 mm3 except 1 territorial infarct of 1900 mm3. Of a total of 41 lesions, 27 (66%) were located in the right hemisphere and 32 in a subcortical location. By 5 days postoperatively, significant neurocognitive decline was observed in 5 of 13 tests affecting memory, attention and rate of information processing. By 4 months, dysfunction had recovered in all cognitive areas. The presence of new ischemic lesions was not associated with neurocognitive decline at discharge. There was also no significant correlation between clinical and operative variables and the presence of new DW lesions or neuropsychological outcome. CONCLUSIONS: Following cardiac valve replacement, new small ischemic brain lesions were detected by diffusion-weighted MRI. Neurocognitive decline was present early after operation, but resolved within 4 months. A correlation of new ischemic lesions to postoperative cognitive dysfunction or clinical variables was not found.

Adult↗
PubMed1991

A numerical analysis of the backflow between the leaflets of a St Jude Medical cardiac valve prosthesis.

Clinically significant, unexplained hemolysis has been reported to occur in St Jude Medical (SJM) cardiac valve prostheses. The leakage phase of backflow is identified as having the most hemolytic potential, when compared with the other phases of the cardiac cycle. A two-dimensional, laminar, constant fluid property finite element analysis (FEA) is used to calculate the peak shear stress obtained in the flow through the narrow slit formed by the closed leaflets of an idealized size 29 mm (tissue annulus diameter) SJM cardiac valve prosthesis, during the leakage phase of backflow. The flow geometry was such that the simple laminar flow theory (SLFT) could be used to model the flow through the region of peak shear stresses with reasonable accuracy. The SLFT predicts that the maximum shear stress depends upon the thickness of the clearance space and the average velocity through that space. These results suggest that the magnitude of the peak shear stress is of the order of 700-1000 Pa for a duration of the order of 0.5-0.4 ms for pressure drops across the valve of 150-300 torr. This suggests that hemolysis is possible for certain unfortunate combinations of clearances and pressure conditions. However, further research is needed before this flow phenomenon can be associated with the reported clinical hemolysis.

Biomechanical Phenomena↗
PubMed1992

Transesophageal color Doppler flow imaging in the evaluation of prosthetic cardiac valves.

To determine the value of transesophageal echocardiography in the assessment of prosthetic cardiac valves, 11 patients with clinically suspected cardiac prosthetic valve dysfunction were studied by transesophageal two-dimensional imaging, as well as by color Doppler flow mapping. Among these 11 patients, there were 10 with biological tissue valves and 3 with metallic valves (1 Bjork-Shiley, 2 St. Jude). Nine patients had replacement of mitral valves alone. The remaining two had received both mitral and aortic prostheses. The degree of mitral regurgitation was graded by transesophageal color Doppler according to the area of the regurgitant jet visualized. The degree of aortic regurgitation was graded by the jet height/left ventricular outflow height ratio method. All transesophageal studies were performed without complication and all were well tolerated. The pathological morphology of the cardiac prosthesis was clearly visualized by transesophageal two-dimensional imaging and subsequently proven at surgery. Of those tested, one patient was found to have a torn leaflet, one had a dislodged leaflet, one patient had paravalvular leakage, four had cusp vegetations, and five patients had prosthetic degeneration for other reasons. Mitral regurgitation was graded as absent in one patient, mild in two patients, moderate in two patients, and severe in six patients. Aortic regurgitation was graded as severe in both patients with aortic prostheses. We conclude that in patients with clinically suspected cardiac prosthetic dysfunction, transesophageal two-dimensional imaging combined with color Doppler can provide reliable information that corresponds to surgical findings.

Adult↗
PubMed1996

Donor-specific cellular immune response against human cardiac valve allografts.

We studied the presence of donor-specific T lymphocytes in explanted human cardiac valve allografts in vivo. From five of seven explants we propagated lymphocyte cultures in an interleukin-2 conditioned medium. Phenotyping revealed the presence of T-cell receptors in more than 95% of the lymphocytes obtained in each culture. Donor-specific cytotoxicity was demonstrated in three patients with known HLA status of the donor. Cytotoxicity was directed against only HLA class I in one patient, and against class I and/or class II in the others. These results indicate that donor-specific cellular reactivity can be induced by transplantation of human cardiac valve allografts.

Adult↗
PubMed1984

The problem of cardiac valve prostheses, anticoagulants, and pregnancy.

To assess the maternal and fetal risks in patients with cardiac valve prostheses, a series of 223 pregnancies in 156 women was studied. In 68 pregnancies (group I) treatment with antiplatelet agents was substituted for that with coumarinics from the first trimester on. Group II (128 pregnancies) received coumarinics through the thirty-eighth week of gestation. Three patients in group I died as a result of thrombosis of their caged-ball valves. The incidence of cerebral embolism was 25.0% in group I and 2.3% in group II patients, while that of spontaneous abortion was 10.3% and 28.1%, respectively. Coumarin embryopathy was found in 7.9% of group II infants. Fetal death did not occur in the 12 cases in which subcutaneous heparin was substituted for the coumarin derivative in the first trimester and the last 2 weeks of pregnancy (group III), but maternal cerebral embolism developed in 8.3% of the patients. Finally, uneventful pregnancies and deliveries were observed in 12 of 15 mothers (group IV) with biological prostheses who received no anticoagulants. It is concluded that (1) women with cardiac valve prostheses should be counseled against becoming pregnant, (2) antiplatelet agents do not provide protection against thromboembolism in these patients, (3) because of the high incidence of fetal death and birth defects use of coumarinics is contraindicated in the first trimester and the last weeks of pregnancy, (4) the substitution of heparin at these times may decrease the incidence of these complications, and (5) bioprostheses are indicated in women who wish to bear children.

Acenocoumarol↗
PubMed1979

A new cardiac prosthesis: the St. Jude Medical cardiac valve: in vivo results.

The St. Jude Medical cardiac valve prosthesis is a low profile, lightweight, bi-leaflet, central-flow device constructed entirely of pyrolytic carbon. In vivo testing was performed in 24 cows in which the tricuspid valve (n = 14) or mitral valve (n = 10) was replaced by a St. Jude Medical prosthesis with a 26 mm tissue annulus diameter. Eight animals died in the operative period. The 16 surviving animals were sacrificed at 4, 8, 12, or 18 weeks. There were no valve-related deaths nor mechanical valve failures. Anticoagulation was not used in the postoperative period during which time monthly laboratory parameters were obtained including hemoglobin, hematocrit, white cell count, red cell count and indices, lactic acid dehydrogenase, serum haptoglobin, and, additionally at sacrifice, platelet and red cell morphology. Values indicated this prosthesis did not cause hemolysis. At sacrifice the pulmonary arterial tree and peripheral organs showed no evidence of thromboemboli. There was smooth endocardial ingrowth on all valve sewing rings. One valve had thrombus formation on the valve sewing ring. Nine animals were anesthetized prior to sacrifice and underwent open cardiac catheterization. Ventriculography (n = 6) showed minimal transvalvar reflux, and atriograms (n = 6) demonstrated central flow. Transvalvar gradients were 0 to 22 mm Hg (n = 9). One valve of an 18-week tricuspid implant was examined for wear; valve life was calculated to be greater than 2500 years. These data in conjunction with in vitro test results justify clinical trial of the St. Jude Medical prosthesis.

Animals↗
PubMed1979

Cardiac valve replacement in congestive heart failure due to infective endocarditis.

From January 1961 to July 1974, 138 patients underwent cardiac valve replacement because of complications of infective endocarditis. The overall operative mortality was higher in patients with Class IV cardiac functional disability (17%) than in patients with Class III (7%) or II (8%). The mortality for patients who had undergone aortic valve replacement with Class IV disability was higher (22%) than that for patients with Class III (0) or II (6%). When compared with patients without infective endocarditis who had undergone cardiac valve replacement, the operative mortality per valve replacement was approximately the same when the degree of cardiac disability was the same at the time of surgery for both groups of patients. Patients with aortic regurgitant murmurs caused by infective endocarditis should be observed closely for the onset of heart failure, especially during the first month of disease. In patients with aortic or mitral incompetence, if heart failure develops or progresses during the first month, we believe that prompt cardiac valve replacement should be considered, because even heart failure that may initially appear mild often progresses to severe heart failure during this period.

Aortic Valve Insufficiency↗
PubMed1984

A modified nonpulsatile flow system for the in vitro study of cardiac valve prostheses.

An in vitro system was constructed for measurements of resistance to forward flow by cardiac valve prostheses at a wide spectrum of flow rates. There was a close correlation between the known area of constriction (valvular orifice) and that calculated from the flow/pressure relationship using derivations of the Bernoulli equation. This simple setup appears particularly suited to determine hydrodynamic efficiency of various cardiac valve concepts on a comparative basis.

Heart Valve Prosthesis↗
PubMed1993

Ventilatory anaerobic threshold before and after cardiac valve surgery.

The purpose of this study was to objectively assess exercise tolerance before and after cardiac valve surgery by using an objectively determined ventilatory anaerobic threshold (AT). Nine patients (mean age: 38.2 +/- 8.1 years) with predominantly mitral regurgitant lesions were studied by a symptomatic maximal treadmill exercise test which included a determination of AT. The mean lengths of time from preoperative exercise testing to cardiac surgery, and from surgery to postoperative exercise testing were 5.9 +/- 4.0 and 12.1 +/- 8.3 months, respectively. The determination of AT on data plots was performed after blinding to patient identification and pre- vs postoperative status. After surgery, the clinical symptoms and NYHA class improved significantly with a decrease in the cardio-thoracic ratio and echocardiographic diastolic dimensions. The mean peak VO2 (ml/kg/min) increased significantly from 20.2 +/- 7.1 to 29.7 +/- 7.9 (p < 0.01). Together with these changes, AT (ml/kg/min in VO2) increased from a mean of 14.8 +/- 4.8 to 22.8 +/- 5.5 (p < 0.01). In conclusion, symptomatic improvement and an increase in peak oxygen uptake after cardiac valve surgery were accompanied by a significant increase in the objectively determined AT. AT determined in a blind manner provides an objective means of evaluating exercise tolerance when a double-blind intervention cannot be performed.

Adult↗