Early result comparison following mitral valve replacement with partial or entire subvalvular structure preservation

21 patients after mitral valve replacement with partial subvalvular structure preservation and 20 patients with entire subvalvular structure preservation were compared with 26 patients after mitral valve replacement with entire subvalvular structure excision. We found that patients after mitral valve replacement with partial or entire subvalvular structure preservation had a more uneventful postoperative course with less inotropic therapy and more decreased left atrial dimension when compared to those with conventional mitral valve replacement. But the patients after mitral valve replacement with entire mitral structure preservation had more decreased left ventricular dimension and short hospital stay when compared to those of the other two groups. The authors suggest that mitral subvalvular structure should be preserved, and we especially recommend the procedure of intravalvular implantation of mitral prosthesis with entire mitral subvalvular structure preservation.     

Mitral subvalvular apparatus: different functions of primary and secondary chordae

BACKGROUND: The aim of this study was to compare the function of the primary chordae attached to the free edge with that of the secondary chordae attached to the ventricular surface of the anterior mitral leaflet. METHODS AND RESULTS: An isolated working pig heart model was used. Three groups of 7 hearts were compared: Group A was the control group with intact leaflets. In group B, the primary chordae of the anterior leaflet were sectioned and the secondary chordae were left intact before assembly of the working heart model. In group C, the secondary chordae were sectioned and the primary chordae left intact. In group B, atrial and ventricular pressure evidenced dramatic mitral regurgitation. Video monitoring showed significant prolapse of the free edge of the anterior leaflet. Acute mitral regurgitation accounted for the decrease in aortic flow rate to 30 mL/min, significantly lower than in the control group (P=.006). In group C, sectioning of the secondary chordae left a competent mitral valve together with good coaptation of the anterior and posterior leaflets shown by video monitoring. However, aortic flow was lower than in the control group (P=.007), and ultrasonomicrometry evidenced impaired function (P=.009). CONCLUSIONS: This study suggests that the primary and secondary chordae of the mitral subvalvular apparatus have different functions. The primary chordae of the anterior leaflet appeared to be more involved in mitral valve competence, whereas the secondary chordae appeared to be more involved in left ventricular geometry and function.     

Blood rheology in patients with native heart valve disease and after valve replacement

Patients with heart valve disease have rheologic abnormalities that are more pronounced in double valve disease than in mitral or aortic valve disease; after valve replacement surgery, the degree of rheologic abnormality is more pronounced in patients with mechanical and biological prostheses than in those with homografts and pulmonary autografts. Rheologic abnormalities seen in these patients might be related to the different incidences of thromboembolism in the presence of various valve defects and various types of prostheses.     

Mitral valve replacement using a cryopreserved mitral homograft

Mitral valve replacement, using a cryopreserved mitral homograft, was performed in a 49-year-old patient with calcified mitral stenosis. Postoperative course was uneventful. Transesophageal echocardiography performed 6 months later showed normal function of the mitral homograft.     

Mitral valve replacement under beating heart in 137 cases

To avoid damage of myocardial ischemia, myocardial hypoxia and reperfusion injury, we designed mitral valve replacement in beating heart under extracorporeal circulation with low dose temperature of 31 degrees C to 35 degrees C in 137 cases of rheumatic heart disease, congenital heart disease mitral stenosis and mitral insufficiency, or concurrent aortic insufficiency. The patients were rept in unblocking aorta, unfilling cardiac arrest perfusion, idle pulse and dradycardia of 40-50 times/min, nose temperature of 32 +/- 1 degrees C. Patients with concurrent aortic insufficiency should first undergo replacement of aorta under cold cardiac arrest and then replacement mitral valve under beating heart to reduce the time of cold heart ischemia. Plastic surgery for tricuspid valve was done under beating heart. Good postoperative prognosis was nated: an average arterial pressure of 9.5-10.5 kPa (70 to 80 mmHg), dose of dopamine was obviously reduced. No low cardiac output syndrome, acute renal failure and severe arrythmia were observed in 137 cases, except 4 deaths due to infection and blood coagulation (2.9%). A left cardiac chamber no-level air removal device and aorta perfusioner leading flow device were designed for exsufflation of left pneumatocardia.     

Mitral valve repair vs replacement. Current recommendations and long-term results

Techniques now exist to correct abnormalities of all components of the mitral valvular apparatus except extensive loss of pliable leaflet area. Thus, paradoxically, myxomatous valves with redundant leaflets represent the ideal candidates for mitral valve repair. Repair for mitral insufficiency can be performed for some rheumatic valves, but patient selection is critical. Loss of leaflet area, leaflet thickening, and extensive calcification of the leaflets or commissures are contraindications to repair. The abnormalities of the subvalvular apparatus are less important because a complete set of new chordae can be reconstructed using PTFE suture material. Some cases of endocarditis are ideal for repair using localized débridement and pericardial patch repair with or without PTFE chordal replacement. True ischemic mitral regurgitation of the Carpentier type I category is still something of a surgical enigma. Because it is a restrictive leaflet motion problem, annuloplasty alone is not always effective, and the outcome of any given repair attempt is less predictable. Repairs in patients with small annuli and multiple leaflet defects requiring complex series of maneuvers have a low probability of success. Furthermore, such patients with small left ventricular cavities are more prone to experience SAM. Several factors contributing to which therapy is chosen for mitral valve disease are summarized in Table 1. Patient selection, accurate evaluation of the cause or causes of mitral regurgitation, and well-executed application of the appropriate techniques for repair are all critical factors in the early and late success of mitral valve repair.     

Plausibility in selecting the method of mitral valve replacement preserving the posterior subvalvular tissue

Seizures are the most common serious complication of flumazenil usage in adults. We report a prolonged seizure in an 11-month-old child that occurred immediately after the administration of 0.3 mg of flumazenil. Precautions recommended for the administration of flumazenil in adults should also be used in pediatric patients.     

Results of Biocor stentless valve replacement for infective endocarditis of the native aortic valve

The mid-term results in a selected group of 9 patients with native aortic valve endocarditis managed by aortic valve replacement (with or without complex annular reconstruction) using a totally biological stentless valve are outlined. At a mean follow-up of 48 months, there are currently 7 survivors (2 late noncardiac deaths) with 100% freedom from reoperation, valve-related complication, and endocarditis.     

Venous gangrene of the lower limbs following aortic valve replacement for native valve endocarditis

Single-shot spin-echo diffusion-weighted echo-planar imaging using a phased-array multicoil was performed to distinguish between normal and cirrhotic livers. Sets of 6 images with different b-values were acquired with breath-holding. Significant differences were observed between controls and cirrhosis cases in the signal ratios when the b-value was 383 s/mm2, and apparent diffusion coefficients.     

Comparative evaluation of left ventricular performance after mitral valve repair or valve replacement with or without chordal preservation

Germinating barley produces two alpha-amylase isozymes, AMY1 and AMY2, having 80% amino acid (aa) sequence identity and differing with respect to a number of functional properties. Recombinant AMY1 (re-AMY1) and AMY2 (re-AMY2) are produced in yeast, but whereas all re-AMY1 is secreted, re-AMY2 accumulates within the cell and only traces are secreted. Expression of AMY1::AMY2 hybrid cDNAs may provide a means of understanding the difference in secretion efficiency between the two isozymes. Here, the efficient homologous recombination system of the yeast, Saccharomyces cerevisiae, was used to generate hybrids of barley AMY with the N-terminal portion derived from AMY1, including the signal peptide (SP), and the C-terminal portion from AMY2. Hybrid cDNAs were thus generated that encode either the SP alone, or the SP followed by the N-terminal 21, 26, 53, 67 or 90 aa from AMY1 and the complementary C-terminal sequences from AMY2. Larger amounts of re-AMY are secreted by hybrids containing, in addition to the SP, 53 or more aa of AMY1. In contrast, only traces of re-AMY are secreted for hybrids having 26 or fewer aa of AMY1. In this case, re-AMY hybrid accumulates intracellularly. Transformants secreting hybrid enzymes also accumulated some re-AMY within the cell. The AMY1 SP, therefore, does not ensure re-AMY2 secretion and a certain portion of the N-terminal sequence of AMY1 is required for secretion of a re-AMY1::AMY2 hybrid.     

Mitral valve replacement with the St. Jude Medical prosthesis: a 15-year follow-up

BACKGROUND: A retrospective study was conducted to analyze the results of St. Jude Medical mitral valve replacement. METHODS: From January 1979 to December 1989, 870 patients (54% women, 46% men; mean age, 55.8 +/- 6.2 years) underwent mitral valve replacement with the St. Jude Medical prosthesis. Of these operations 616 were isolated mitral valve replacements and 254 were double valve replacements. Coronary artery bypass grafting was performed concomitantly in 55 patients (6.3%). RESULTS: Overall, early mortality was 5.05%, with 4.2% for the isolated mitral valve procedure and 7.08% for the double valve replacement. Follow-up at 15 years was complete in 859 patients (98.74%). Mean follow-up time was 93.5 months, for a total of 6,436 years. Actuarial survival at 15 years was 59.5% +/- 5%, 60.5% +/- 6%, and 56.9% +/- 9%, for the entire group, the isolated mitral valve and double valve procedures, respectively. Multivariate analysis identified age, sex, hospital stay, and preoperative mitral regurgitation as independent prognosis factors for overall mortality. Of 606 patients alive at the latest follow-up, the New York Heart Association class improved significantly (from 67% class III/IV before the operation to 88% class I/II after the operation). All patients received warfarin to maintain an international normalized ratio between 3.5 and 4. The linearized rates (% per patient-year) of thrombosis, thromboembolism, and major hemorrhage were, respectively, 0.21, 0.75, and 0.94 for the entire group; 0.18, 0.67, and 0.88 for the isolated mitral valve operation; and 0.15, 0.92, and 1.08 for the double valve replacement. For the entire group the freedom from thrombosis and thromboembolism at 15 years was 98.1% +/- 1% and 88% +/- 4%, respectively. No case of structural dysfunction occurred. The freedom from paravalvular leak and endocarditis at 15 years was 95.3% +/- 2% and 97.3% +/- 2.4%, respectively. The probability of remaining free from reoperation at 15 years was therefore 95.6% +/- 2.5%. CONCLUSIONS: These results confirm that the St. Jude Medical valve is a reliable prosthesis with very low thrombosis and thromboembolism rates, allowing the use of a low dose of anticoagulation with an international normalized ratio of about 3.     

Mitral valve replacement: randomized trial of St. Jude and Medtronic Hall prostheses

BACKGROUND: This study was designed to better define the merits of the bileaflet and tilting-disc valves. METHODS: We prospectively randomized 156 patients (mean age, 59 years) to receive either the St. Jude (n = 80) or the Medtronic Hall (n = 76) mitral valve prosthesis between September 1986 and December 1997. The two groups were not significantly different with respect to preoperative New York Heart Association class, left ventricular ejection fraction, incidence of mitral stenosis or insufficiency, extent of coronary artery disease, completeness of revascularization, or cross-clamp or bypass time. RESULTS: The operative mortality (11.2% versus 13.1%, St. Jude versus Medtronic Hall, respectively) and late mortality (27% versus 22%, St. Jude versus Medtronic Hall, respectively) were not significantly different. Follow-up was complete in all hospital survivors with a mean of 60.7 months (range, 1 to 133 months). The analysis of 10-year actuarial survival and freedom from valve-related events demonstrated no significant differences between the cohorts. Freedom from reoperation was higher in the St. Jude group (p < 0.01). Comparisons of patient functional status and echocardiographic hemodynamic parameters obtained at the time of follow-up demonstrated no significant differences between the two prostheses. CONCLUSIONS: This study suggests that there is no difference between the St. Jude and Medtronic Hall prostheses with respect to late clinical performance or hemodynamic results and therefore does not support the preferential selection of either prosthesis.     

Mitral valve replacement and coronary artery bypass grafting for postinfarction mitral papillary muscle rupture

A 79-year-old man was admitted to our hospital with heart failure following acute inferior myocardial infarction. An echocardiogram demonstrated severe mitral insufficiency, and coronary arteriography revealed double vesel disease. Following diagnosis of ischemic papillary muscle dysfunction, PTCA was performed, but the mitral insufficiency was not eliminated. Follow-up echocardiography disclosed rupture of the posterior papillary muscle. He underwent surgery on the 30th day after onset of acute myocardial infarction. Partial rupture of the posterior papillary muscle was found at surgery, and mitral valve replacement and single coronary artery bypass to Lcx were performed. His postoperative course was uneventful, and he was discharged on the 46th day after operation.     

Evaluating techniques of myocardial preservation for aortic valve replacement: operative risk

The authors observed two cases of hyperprolinaemia (one of type I and the other of type II) which were asymptomatic. The anomalies described up to the present time in association with hyperprolinaemia are inconstant, nonspecific, and extremely heterogeneous. This suggests that the relationship between hyperprolinaemia and other anomalies is purely coincidental, and that a therapeutic approach by diet is unjustified.     

A generalized consideration of myocardial preservation with cold crystalloid versus warm blood cardioplegia in heart valve replacement

The spontaneous as well as mitogen-induced in vitro production of interleukin-6 (IL-6) was studied in cultures of peripheral blood mononuclear cells (PBMC) from 14 children with marginal protein-energy malnutrition, 43 children with definite protein-energy malnutrition and 38 eutrophic controls of similar age, sex, race and socioeconomical condition. PBMC were cultured without added mitogen or stimulated with either lipopolysaccharide (LPS) or phytohemagglutinin (PHA). After 48 h incubation, cell-free culture supernatants were collected and stored at -70 degrees C. The amount of IL-6 in the supernatants was determined by a specific bioassay based on the proliferation of B9 hybridoma cells using human rIL-6 as standard. The mean level of IL-6 was significantly increased in supernatants from nonstimulated PBMC cultures from definitely malnourished children as compared with that observed in those of the controls. Stimulation with either LPS or PHA induced a rise in cytokine bioactivity in the supernatants of PBMC cultures from the different nutritional groups tested. Interestingly, IL-6 was significantly increased in the supernatants of PHA-stimulated cultures from malnourished children as compared with those of the controls.     

Aortic valve replacement with biological substitute

In the quest for an ideal aortic valve substitute, homografts and autografts are well-established options. We reviewed our results with homografts and autografts for aortic valve replacement during the last 5 years. From March 1992 through July 1997, 189 patients (138 male and 51 female), age 8 months to 68 years (mean 31.0+/-4.2 years), underwent aortic valve replacement with a human biological substitute. Of these, 93 patients received a cryopreserved or antibiotic-preserved aortic/pulmonary homograft, whereas 96 patients underwent a Ross procedure. Etiology was rheumatic in 143 (75.6%) patients, bicuspid aortic valve in 40 (21.2%), Marfan's disease in 5 (2.6%), and myxomatous aortitis in 1 (0.5%). Among the homograft group, a scalloped subcoronary implantation technique was used in 54 patients, whereas 32 patients underwent root replacement. Five patients required aortic root and ascending aortia replacement for annuloaortic ectasia. In all patients undergoing the Ross procedure, a root replacement technique was used. Operative mortality was 7.4% (14 patients). Late mortality was 5.3% (10 patients). Follow-up ranged from 1 to 46 months postoperatively. In patients with homograft aortic valve replacement, 76 patients (91.5%) had trivial to mild aortic regurgitation, while 7 patients (8.4%) had important aortic regurgitation. In patients with the Ross procedure, 78 patients (89.6%) had trivial to mild regurgitation. Moderate to severe aortic regurgitation was present in 9 patients (10.3%), all of whom had rheumatic heart disease and were young (< 30 years at surgery). We conclude that homografts and autografts provide an excellent substitute for the diseased aortic valve. Young age (< 30 years) with rheumatic etiology is a major risk factor for early progressive aortic regurgitation in patients undergoing the Ross procedure.