Allograft valves for aortic and mitral valve replacement

OBJECTIVE: To evaluate nuclear grading on fine needle cytopunctures of breast carcinoma, which is of special interest when neoadjuvant chemotherapy is planned. STUDY DESIGN: In a prospective study, we compared cytologic grading, based on nuclear parameters (pleomorphism and mitosis), to modified Scarff-Bloom-Richardson histologic grading in 105 primary operable breast carcinomas. The results of these two nuclear grading systems were compared to Feulgen image analysis data from the corresponding cytologic samples. RESULTS: The concordance rate between the two grading systems was 76%. Concordance between cytologic and histologic grading was observed more frequently in purely invasive carcinomas (85%) than in cases combining invasive and in situ components (56%). A highly significant relationship was observed between the two grading systems and indices of proliferative activity (S-phase fraction, proliferation index, 5c exceeding rate and endoreduplication rate), particularly in concordant grading. Furthermore, nuclear area correlated with the results of the two grading systems. CONCLUSION: Cytologic nuclear grading appeared to be a reliable tool for a large proportion of breast tumors. Despite difficulties related to tumor heterogeneity, which could be detected by careful cytologic examination, it is a useful alternative to histologic grading.     

Improvement in mitral regurgitation after aortic valve replacement

This study sought to determine whether there is a quantitative improvement in mitral regurgitation (MR) after aortic valve replacement (AVR) for aortic stenosis (AS) and, if so, the mechanisms for this change. MR frequently accompanies AS. The addition of mitral valve replacement to AVR significantly increases the risk of surgery. Although previous studies have suggested a qualitative improvement in MR severity after AVR, semiquantitative analysis of this improvement has not been documented nor have the underlying mechanisms been examined. We evaluated 28 patients who had undergone 2-dimensional echo and color flow Doppler imaging an average of 1.5 +/- 2.5 months before and 2.5 +/- 4.2 months after AVR. Maximum MR area, MR percentage (MR area/left atrial area), mitral annular area, left atrial area, aortic gradient, and parameters of left ventricular geometry were measured to evaluate MR severity and to assess functional mechanisms for improvement in MR. There was a significant decrease in MR area (5.5 +/- 2.8 cm2 vs 2.5 +/- 1.9 cm2, p < or =0.0001) and MR percentage (25 +/- 11% vs 12 +/- 10% after operation, p < or =0.0001) between preoperative and postoperative studies. There was a significant reduction in aortic gradient, mitral annular area, left atrial area, and left ventricular length postoperatively. In univariate analysis, MR improvement was related to the lower preoperative left ventricular fractional area change (p = 0.027) and to the changes in fractional area change (p = 0.001) and left ventricular systolic area (p = 0.001). Thus, improvement in MR after AVR is related to changes in left ventricular function postoperatively. These data suggest that reduction in MR is due not only to decreased intraventricular pressure, but also to changes in ventricular morphology.     

Effects of valve replacement on ventricular mechanics in mitral regurgitation and aortic stenosis

BACKGROUND: This study in humans assessed changes in left ventricular function early and late after correction of mitral regurgitation (MR) (n = 9) or aortic stenosis (AS) (n = 10). METHODS: Ventricular function was measured with radionuclide and micromanometer-derived pressure-volume loops during preload manipulation, thermodilution cardiac outputs, and echocardiograms. Late radionuclide and echocardiographic data were acquired at 24 hours and 20 months. RESULTS: Perioperative left ventricular performance (stroke work-end-diastolic volume relationship) did not change for patients with MR or AS. Significant changes in afterload occurred: ejection fraction (MR, 0.49 to 0.37; AS, 0.54 to 0.60; both, p = 0.013), mean left ventricular ejection pressure (MR, 73 to 91 mm Hg; AS, 138 to 93 mm Hg; both, p < 0.01), and end-systolic wall stress (MR, 26 to 42 x 10(3) dynes/cm2; AS, 37 to 22 x 10(3) dynes/cm2; both, p < 0.01). Ejection efficiency improved for MR patients (0.69 +/- 0.26 to 1.0 +/- 0.15; p < 0.05). The 20-month data showed improved New York Heart Association functional class, normal resting ejection fraction, and normal exercise response for both groups. CONCLUSIONS: Early after operation, a significant change in left ventricular load was seen with correction of MR and AS. Data obtained late after operation showed improvement consistent with ventricular remodeling.     

Successful aorto-circumflex coronary bypass grafting through left thoracotomy following aortic and mitral valve replacement

We report successful descending thoracic aorto-circumflex coronary artery bypass grafting using a saphenous vein graft through left thoracotomy in a 44-year-old female. The patient developed severe angina attack after aortic and mitral valve replacement. Coronary angiography showed 99% stenosis of the circumflex coronary artery. Under general anesthesia, left femoral vein to arterial partial cardiopulmonary bypass was performed via left 4 th intercostal space. Body temperature was lowered to 22 degrees centigrade, and spontaneous cardiac fibrillation occurred. After minimal exposure by pericardial dissection of the circumflex coronary artery, distal anastomosis and then proximal anastomosis at the descending thoracic aorta was carried out under cardiac fibrillation. This surgery was done with minimal intra-and postoperative bleeding. Postoperative course was very smooth, and the patient was discharged and leading a normal life for 6 months after surgery.     

Long-term Doppler echocardiographic results of aortic or mitral valve replacement with Biocor porcine bioprosthesis

OBJECTIVES: Our objectives were to evaluate the long-term bioprosthetic and cardiac functional outcome after insertion (over a 10-year period) of a new-generation porcine zero pressure-fixed Biocor bioprosthesis, as well as to determine the echocardiographic accuracy for selection of patients requiring reoperation. The long-term systematic Doppler echocardiographic assessment after valve replacement with this bioprosthesis is lacking. METHODS: Between January 1983 and January 1993, we inserted 756 Biocor prostheses in the aortic (619) or mitral (137) positions. All 51 patients who had a reoperation during the follow-up time were evaluated echocardiographically before reoperation. Additionally, 263 of 446 patients (59%) with aortic bioprostheses and 42 of 74 patients (57%) with mitral bioprostheses who were alive in January 1993 had long-term echocardiographic follow-up. RESULTS: Group A: Normally functioning bioprostheses were found in the aortic position in 242 of 263 patients and in the mitral position in 33 of 42 patients. Group B: Thirty patients had abnormal bioprosthetic function. Eleven patients had regurgitation, 3 had a combined lesion, and signs of calcification appeared in 16 patients with aortic valves, all with a peak gradient of above 60 mm Hg. Group C: Patients who had a reoperation (41 aortic and 10 mitral) within the follow-up period were followed up echocardiographically from the detection of a possible valve dysfunction until reoperation, and the findings accorded well with those at operation in 49 of 51 patients. CONCLUSIONS: These findings suggest that, during a long-term follow-up, most bioprostheses function normally, facilitating improved heart function. Abnormalities in a bioprosthesis usually develop gradually, enabling their detection by Doppler echocardiographic evaluations performed regularly or in case of any symptomatic deterioration.     

Combined tracheal resection and aortic valve replacement with a cryopreserved aortic valve allograft

A 69-year-old patient presented with an association of tracheal squamous cell carcinoma and severe aortic valve stenosis. As there was no evidence of metastatic spread a potentially curative resection could be considered. The patient underwent tracheal resection and aortic valve replacement in a one-stage procedure. In light of the potential risk of infection to a prosthetic valve, a cryopreserved aortic valve homograft was implanted. The patient made a full recovery and is doing well after 2 years of follow-up.     

Left ventricular rupture following mitral valve replacement

During a 10-year period, we have encountered 6 patients (mean age, 61.2 years) with left ventricular rupture following mitral valve replacement, with an overall incidence of 1.8 percent. Four patients had early rupture, one had delayed rupture, and one had late rupture with a false aneurysm formation. Among four patients with early rupture, there were two patients with external repair by using a large ventricular patch and two patients with internal and the external repair by removing the prosthetic valve and patching both the inside and outside of the ventricle. In a patient with delayed rupture, bleeding from an epicardial hematoma was recognized along the atrioventricular groove in the intensive care unit. It was possible to control bleeding by packing the gauze, hemostatic cellulose [Surgical], and fibrin glue. Late rupture was recognized as a false aneurysm; however, there were no clinical symptoms. All patients survived the surgery, but two patients with early rupture subsequently died. One of these died of renal failure and the other died of multiple organ failure. The sites of rupture in all patients were in accordance with type 1 rupture (Treasure's classification); however, an autopsy review demonstrated the initial laceration in one case was recognized in the membranous septum 5 mm below the mitral ring and extended to the posterior atrioventricular groove. These findings suggest that the injury in the anterior mitral annulus could lead to type 1 rupture, although in the posterior mitral annulus more commonly. Since 1987, we have preserved the posterior leaflet with attached chordae when the mitral valve was fragile and myxomatous. As a result, no instances of left ventricular rupture were encountered.     

Left ventricular rupture following mitral valve replacement

Rupture of the posterior wall of the left ventricle is an unusual but often lethal complication following mitral valve replacement. The incidence is about 1% of MVRs. Most of the ruptures are attributed either to technical maneuvers in the operation or to stretch injury produced by removal of the mural leaflet of the mitral valve. Surgical repair of the rupture requires the cardiopulmonary bypass, and it seems to be suited that we select extracardiac approach to type 2 or 3 rupture and intracardiac approach to type 1 rupture. Preventive measures include the modifications in operative techniques, reduction of pre and afterload of the left ventricle, and retention of posterior mitral leaflet.     

Successful surgical treatment for type B aortic dissection with Marfan's syndrome after aortic root and mitral valve replacement: report of a case

A 30-year-old female with Marfan's syndrome underwent aortic root replacement for annuloaortic ectasia and mitral valve replacement for mitral regurgitation. She remained well until 16 months postoperatively when she had sudden onset of pain. Preoperative angiogram showed Stanford B aortic dissection. Thoracoabdominal aortic replacement was performed successfully under deep hypothermic bypass.     

Reoperation for mitral regurgitation 13 years after aortic valve replacement and manouguian's anulus enlargement: report of a case

The patient was 22-year-old female. She had undergone aortic valve replacement and Manouguian's anulus enlargement with low porosity woven Dacron patch for congenital aortic stenosis 13 years ago, and developed mitral regurgitation 9 years after that operation. Two regurgitant flow were observed. One was originated from the orifice due to mitral prolapse. The other was from a tear in the anterior leaflet. It was around the tip of the prosthetic patch, approximately 7 mm in size, and was repaired easily. But the mitral valve itself was found to be malformed and prolapsed, requiring mitral valve replacement. Her postoperative course was uneventful.     

Bentall operation, total aortic replacement and mitral valve replacement for a young adult with Marfan syndrome: a case of three-staged operation

BACKGROUND: Early postpartum discharge of babies was gradually introduced in Sweden in the 1980s on ideological grounds, based on the premise that maternity wards were unnatural settings for mothers and babies and hampered breastfeeding. From about 1990, early discharge was used as a means to reduce costs. The purpose of this study was to examine if mandated early discharge at Central Hospital of Karlstad, Sweden, influenced subsequent breastfeeding. METHOD: Breastfeeding outcomes of infants up to six months of age of all births in 1993 (n = 3231) were compared with the outcome of newborns in 1990 (n = 1462). RESULTS: Breastfeeding at six months postpartum continued to increase during the early 1990s for both healthy and sick infants, irrespective of whether or not they were discharged early. In infants born in 1995 the breastfeeding rate at six months was 64 percent for healthy newborns and 53 percent for sick newborns. CONCLUSION: Factors other than the time of discharge, most likely a positive change of attitude in society and vigorous introduction of the Baby Friendly Hospital Initiative, seem to have been more important for successful breastfeeding.     

25 years of aortic valve replacement using mechanical valves. Risk factors for early and late mortality

This study describes the changes that have taken place in patient characteristics in 25 years of aortic valve replacement using mechanical valves, and looks for risk factors for early and late mortality. During this period, 1449 mechanical valves were implanted. Overall early mortality (< 30 days) was 5.3% and for aortic valve replacement without concomitant procedures 3.9%. Overall survival rates at 5, 10 and 15 years were 80%, 63% and 49%, respectively. Despite an increased proportion of higher risk patients (older age, more reoperations, more concomitant coronary bypass surgery) survival rates improved throughout the study period. Early mortality was related to an early year of operation, urgency, reoperation and concomitant surgery to the tricuspid valve or ascending aorta. Late mortality was higher for patients of older age, with an early year of operation, male gender, concomitant coronary bypass surgery, mitral valve surgery or replacement of the ascending aorta. Aortic regurgitation did not have a major influence on early nor late mortality. The improvement in early and late mortality in more recent years was largely the result of the introduction of cardioplegia. A changing, non-proportional effect was observed for several risk factors during the follow-up period. This study illustrates the changes and improvements in medical care that have taken place in patients requiring aortic valve replacement.     

Regression of left ventricular hypertrophy after aortic valve replacement for aortic stenosis with different valve substitutes

OBJECTIVE: Stentless biologic aortic valves are less obstructive than stented biologic or mechanical valves. Their superior hemodynamic performances are expected to reflect in better regression of left ventricular hypertrophy. We compared the regression of left ventricular hypertrophy in 3 groups of patients undergoing aortic valve replacement for severe aortic stenosis. Group I (10 patients) received stentless biologic aortic valves, group II (10 patients) received stented biologic aortic valves, and group III (10 patients) received bileaflet mechanical aortic valves. METHODS: Echocardiographic evaluations were performed before the operation and after 1 year, and the results were compared with those of a control group. Left ventricular diameters and function, left ventricular wall thickness, and left ventricular mass were assessed by echocardiography. RESULTS: Group I patients had a significantly lower maximum and mean transprosthetic gradient than the other valve groups (P = .001). One year after operation there was a significant reduction in left ventricular mass for all patient groups (P < .01), but mass did not reach normal values (P = .05). Although the rate of regression in the interventricular septum and posterior wall thickness differed slightly among groups, their values at follow-up were comparable and still higher than control values (P = .002). The ratio between interventricular septum and posterior wall and the ratio between wall thickness and chamber radius did not change significantly at follow-up. CONCLUSIONS: Because the number of patients was relatively small, we could not use left ventricular mass regression after I year to distinguish among patients undergoing aortic valve replacement for aortic stenosis by means of valve prostheses with different hemodynamic performances.