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Objective: Because of its durability, the mechanical valve is typically chosen for young patients undergoing mitral valve replacement (MVR). However, a bioprosthetic valve might have the benefit of valve-in-valve transcatheter valve replacement when valve failure occurs. We examined the outcomes in patients who had undergone mechanical valve MVR (MVRm) versus bioprosthetic valve MVR (MVRb) in patients aged <65 years., Methods: A total of 768 consecutive patients aged <65 years, who had undergone MVR from January 1991 to June 2012 were identified. Propensity matching was used to derive a case-control subset for analysis. Long-term outcomes were collected by chart review, routine patient follow-up, and query of the Social Security Death Index. The postoperative and long-term outcomes of interest included combined stroke and embolic events, reoperations, and mortality., Results: Of 768 consecutive patients, 627 were in the MVRm and 141 in the MVRb group. Propensity score matching yielded a cohort of 125 MVRb (89%) and 125 control MVRm patients with similar etiology mixes. The groups were similar in age (MVRm, 53.2 ± 9.0 years; MVRb, 53.8 ± 10.6 years; P = .617) and other preoperative characteristics. The postoperative outcomes were also similar between the 2 groups, including reoperation for bleeding, stroke, deep sternal infection, sepsis, and length of hospital stay. The operative mortality was also similar (MVRm, 5.6%; MVRb, 8.0%; P = .617). However, Kaplan-Meier analysis showed the MVRb group had a greater reoperation rate (P = .001) and shorter estimated survival (11.3 vs 13.5 years, P = .004). The incidence of bleeding and stroke or embolic events between the 2 groups was similar., Conclusions: In the present report, MVRb for patients <65 years old was associated with a high reoperation rate and decreased survival. Although a future transcatheter valve-in-valve technique for a failed bioprosthetic valve might reduce the risk of reoperation, this finding confirms the safety of mechanical valves in this group., (Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)

Objective: The natural history of medically treated multivalvular endocarditis is associated with dismal short and long term survival. However, the impact of surgical intervention on these results is relatively unknown. The objective of this retrospective study was to report our long-term results in patients requiring multivalve surgery for multivalvular endocarditis., Methods and Results: Over a 24 year period beginning in 1972, multivalve surgical procedures were performed on 63 patients for infective endocarditis. Prosthetic valve endocarditis was present in 25 (40%), and acute or active endocarditis in 38 (60%). The early mortality was 16%. Out of 53 patients discharged from the hospital 87+/-4% were alive at 5 years and 64+/-9% at 10 years. There was no difference in early or late mortality between patients with prosthetic and native endocarditis (P=0.15 and P=0.77 for early and late mortality, respectively). The presence of active endocarditis did not affect operative outcome or late mortality. Twenty-one patients (88%) were in NYHA FC I, and none were in NYHA FC IV. The only prognostic factor of early and late mortality was the presence of an abscess at the time of the surgery., Conclusions: These results indicate that multivalve infective endocarditis treated surgically is associated with acceptable early and late mortality and excellent postoperative functional status. The early surgical intervention prior to an abscess formation offers the best chance for survival of patients with multivalve endocarditis.

Objective: Ideal management of the elderly patient with a small aortic root remains controversial. This retrospective analysis was performed to determine whether small prosthetic valve size is related to outcome in patients 70 years of age or older undergoing aortic valve replacement for aortic stenosis., Methods: Between December 1991 and July 1998, 366 patients 70 years of age or older (median age 77 years, range 73-81 years, 49% male) underwent isolated aortic valve replacement or aortic valve replacement with coronary bypass grafting with standard Carpentier-Edwards bovine pericardial valves (Baxter Healthcare Corp, Edwards Division, Santa Ana, Calif) (n = 277; 76%) or St Jude Medical mechanical valves (St Jude Medical, Inc, St Paul, Minn) (n = 89; 24%). Propensity scoring and multivariable regression models were used to evaluate the risks associated with implantation of 19-mm valves., Results: Operative mortality was 16.7% (17/102) in patients who received 19-mm valves and 3% (8/264) among those receiving >/=21-mm valves (P /=21-mm valves was 6.4 (95% CI 2.7, 15.4; P

Background: The entire experience with the Hancock modified orifice porcine bioprosthetic aortic valve from 1976 to 1996 at the Brigham and Women's Hospital has been reviewed. Eight hundred forty-three patients received this valve with a total follow-up of 61,114 months, and a mean follow-up of approximately 72.5 months. There were 490 men and 353 women, and the predominate lesion was aortic stenosis (636 of 843); 365 (43%) patients required a concomitant coronary artery bypass graft operation., Methods: Patients were followed prospectively in the Brigham Cardiac Valve Data Registry, and the data were analyzed by the SAS statistical package, using actuarial survival curves and incidence per patient-year of morbidity and mortality., Results: The overall operative mortality was 45 of 843 (5.3%) with 23 of 478 (4.8%) for isolated aortic valve replacement and 22 of 365 (6.0%) for aortic valve plus coronary artery bypass graft operation. The major morbidity of this valve was structural valve dysfunction, which was significantly related to the age of the patient in whom the valve was placed. Actuarial probability of freedom from structural valve degeneration at 5, 10, and 15 years overall was 99%+/-1%, 79%+/-3% and 57%+/-4%, at 15 years, respectively. In patients younger than 50 years, freedom from structural valve dysfunction was 16%+/-8%, whereas in the age group older than 70 years it was 87%+/-5% (p = 0.0005). Thromboembolism at 10 and 15 years was 81%+/-3% overall, 84%+/-2% in patients in normal sinus rhythm, and 57%+/-13% in patients with chronic atrial fibrillation., Conclusions: The Hancock modified orifice aortic valve, despite its more complicated fabrication, has been a reliable porcine bioprosthetic valve and can be used reliably in patients older than 70 years because of its low structural valve degeneration rate, and protection from stroke and anticoagulant hemorrhage in those patients in sinus rhythm.

Background: Aortic valve replacement remains the treatment of choice for aortic valve disease, even in the extreme elderly who may present with advanced symptoms. Defining risk factors for short-term survival was the object of this study., Methods and Results: This was a retrospective analysis of 717 patients at least 70 years of age who underwent aortic valve replacement alone or with coronary artery bypass graft between 1980 and 1992. Age range was 70 to 95 years, and mean age was 77 years; there were 529 septuagenarians (74%); 188 were octogenarians (26%); 326 were women (45%); and 386 patients (54%) had aortic valve replacement and coronary artery bypass graft. Atrial fibrillation/flutter or heart block was present in 16%, and 34% of patients were in New York Heart Association (NYHA) functional class IV. Aortic stenosis was present in 88%, and mechanical prostheses were used in 22% of patients. There were 47 deaths, giving an overall operative mortality of 6.6%, with 4.2% for aortic valve replacement and 8.8% for aortic valve replacement and coronary artery bypass graft (P = .01). The operative mortality for aortic valve replacement was 2.9% versus 10.3% for aortic valve replacement and coronary artery bypass graft in women (P = .006). The corresponding values for men were 5.6% and 7.4% (P = .31). Multivariate logistic regression showed coronary artery bypass graft and NYHA class IV to be significant predictors of operative mortality in women. The significant predictors in men were NYHA class IV, atrial fibrillation/flutter or heart block rhythm, and the use of mechanical prosthesis. Age was not a predictor of operative mortality in either sex., Conclusions: Aortic valve replacement carries an acceptable mortality rate in elderly patients. Female gender was a significant predictor of operative mortality in the concomitant coronary artery bypass graft group; however, gender was not a predictor of operative mortality in the isolated aortic valve replacement group. Advance stage of the disease process represented by NYHA class IV was a significant predictor of mortality for the whole group, stressing the need for earlier referral for surgery.

The Hancock Modified Orifice valve is a specially fabricated, trileaflet porcine valve, which has been in clinical use at the Brigham and Women's Hospital since 1976. Three hundred seventy-nine aortic valve replacements with this device were implanted from 1976 to 1985; 305 were isolated aortic valve replacements and 74 were in association with a mitral valve bioprosthesis. The 305 patients undergoing isolated aortic valve replacement, a Food and Drug Administration patient group, are the subject of this article. The mean valve size was 22.5 mm, with 115 21-mm valves used. The mean functional preoperative class was 3.2; 99 of 305 patients (32.5%) underwent concomitant coronary artery bypass grafting. There were six operative deaths (2%). Patients were followed from 6-14 years (mean 7.4 years), and analysis was completed in early 1991. The 10-year actuarial calculation of survival freedom from reoperation, thromboembolism, structural valve degeneration, perivalvular leak, infectious valve degeneration, and total morbidity and mortality are presented.

The Hancock porcine xenograft valve was the first commercially prepared, quality-controlled tissue valve. The National Institutes of Health group began implantation of this valve in 1970 and reported on the first 5 years of their results, which was one of the longest follow-ups of that valve at that particular time. Since then there have been a number of centers that have had long-term experience with thousands of these valves. In retrospect, it is now clear that some of the conclusions made by the National Institutes of Health group have not come to pass, such as this valve being the "valve of choice" for all patients. "Valve of choice" is a relative term and may be one valve for one patient and another valve for another patient. This report was important in bringing together some of the first medium-term data and pointing out that, even in this valve, there was some small degree of thromboembolism. The paper also provided a historical look at the methods of data analysis that were in use in the early 1970s compared with those now used in 1991. Actuarial curves were not yet commonly used, nor were percent/patient-year linearized results. Valve types were mixed as well. Hemodynamic data, always a strong point of National Institutes of Health data analysis, were excellent. The use of this valve became a fairly standard device and has been retrospectively analyzed by a number of centers, suggesting that now it is better used in the older patient or in patients who cannot take warfarin sodium.(ABSTRACT TRUNCATED AT 250 WORDS)

The collection of clinical cardiac surgical articles published in the last year about valvular heart disease emphasizes the continuing accrual of data that compare prosthetic and bioprosthetic valves and suggest advantages and disadvantages of both: the indications for and long-term results of aortic valve replacement, particularly in patients with left ventricular dysfunction; newer elements of mitral valve reconstruction; and debate about the best operation for the tricuspid valve. A miscellaneous collection of interesting articles discusses endocarditis and anticoagulation in the pregnant patient who undergoes heart surgery.

To study the natural history of the hemodynamic performance of bioprosthetic heart valves, Doppler echocardiograms were recorded in a group of clinically stable patients at 2 and 5 years after replacement of native aortic valves with bioprosthetic valves. Eighteen patients completed a 2-year and 26 patients a 5-year follow-up examination. The effective orifice areas of identical models of bioprosthetic valves (Hancock II) were determined in vitro in a left-sided heart pulse duplicator system. In vivo Doppler-derived effective orifice areas were compared with the in vitro measurements for the same valve size. At both the 2- and 5-year follow-up examinations, the Doppler-derived effective orifice area was significantly less than the in vitro area (p less than 0.0001 at each interval). Ten of 16 valves evaluated serially decreased greater than 0.20 cm2 in the Doppler-derived effective orifice area between studies. The mean decrease in effective orifice area in valves evaluated serially was 0.25 +/- 0.29 cm2 (p less than 0.005). The peak transaortic gradient increased from 21 +/- 6 to 27 +/- 8 mm Hg (p less than 0.01). The mean transaortic gradient increased from 12 +/- 4 to 15 +/- 7 mm Hg (p less than 0.05). It is concluded that serial Doppler echocardiographic studies demonstrate a deterioration in the hemodynamic performance of bioprosthetic valves over time in patients with no symptoms or signs of valvular dysfunction and that Doppler echocardiography may be useful for identifying subclinical bioprosthetic valvular dysfunction.

A 25-year-old woman with active systemic lupus erythematosus and infective endocarditis was seen initially with porcine aortic bioprosthetic stenosis, perivalvar regurgitation, and native mitral regurgitation 9 years after aortic valve replacement for lupus endocarditis. Double-valve replacement was performed with St. Jude Medical mechanical prostheses. After operation the patient developed fever and an elevated white blood cell count. One month later she had increasing mitral and aortic perivalvular regurgitation and intermittent complete heart block. At reoperation both annuli showed evidence of continued infection, and she underwent annular reconstructions with pericardium and double-valve re-replacement. Cultures grew Mycoplasma hominis. Despite long-term therapy with appropriate antibiotics, within 2 months she developed recurrent perivalvar regurgitation with congestive heart failure. Orthotopic heart transplantation was performed. The postoperative course was notable for significant leukocytosis and spontaneous culture negative hemothorax that required thoracotomy for drainage. The patient recovered and is now well 14 months after operation.

To ascertain relations among site, incidence, and mechanisms of clinically evident failure of porcine bioprosthetic heart valves, the frequency of failure of 1,110 valves in 1,001 adult operative survivors from January 1972 to January 1982 was reviewed and correlated with the pathologic features of 22 consecutive dysfunctional valves. There were 373 mitral, 519 aortic, and 109 double replacements, yielding for study 482 mitral and 628 aortic valves at risk. Infective endocarditis occurred in 1.9% (8 mitral, 7 aortic, and 4 double). Twenty-three valves (13 mitral and 10 aortic) with documented primary dysfunction were explanted, a mean of 55 months (range 9 to 94) after surgery. The primary dysfunction rate for the 333 valves implanted for greater than or equal to 5 years was 6.8% (11 of 161) for mitral and 4.1% (7 of 172) for aortic valves. Valves implanted for less than 5 years had a failure rate of 0.7%. The actuarially determined freedom from primary valve failure was 98 +/- 1% for mitral and 98 +/- 1% for aortic valves at 5 years and 79 +/- 7% for mitral and 91 +/- 4% for aortic valves at 10 years. Recovered valves (12 mitral and 10 aortic) with detailed morphologic analysis were functioning for a mean duration of 52 months (range 12 to 87). Causes of failure included calcification-related tears in 7 (4 mitral and 3 aortic, mean 66 months), tear without calcium deposits in 4 (4 mitral, mean 44 months), cuspal stiffening without tear but with calcium deposits in 2 (1 mitral and 1 aortic, mean 80 months) and thrombosis in 1 (aortic). Late primary dysfunction was most frequently a result of degenerative processes, especially calcification, often with secondary tears, but cuspal tears in the absence of calcium deposits and thrombosis predominated at shorter intervals.

To evaluate the clinical course after porcine heart-valve replacement, we followed 128 patients for five to eight years after surgery. Aortic-valve replacement was performed in 47 patients, mitral-valve replacement in 62, and combined aortic-valve and mitral-valve replacement in 19. Four patients died within 30 days of surgery (operative mortality, 3 per cent), and 20 died later (16 per cent); the actuarial probability of survival at eight years for all patients was 80 +/- 4 per cent (mean +/- S.E.M.). Thromboemboli were found in two of 43 patients after aortic-valve replacement, in nine of 62 after mitral-valve replacement, and in four of 18 after combined aortic-valve and mitral-valve replacement. Valve dysfunction resulted from bacterial endocarditis in five patients (4 per cent) and from primary valve dysfunction in another five.

This study investigated the in vivo hemodynamics and pathologic changes of a unileaflet pericardial bioprosthetic valve 3 to 5 months after implantation in juvenile sheep. Group 1 had 10 sheep with tricuspid valve replacement. Group 2 had nine sheep with mitral valve replacement. Group 3 served as a control with 10 sheep that had tricuspid valve replacement with a trileaflet porcine bioprosthesis. Hemodynamic performance was satisfactory in all three groups despite prominent pathologic changes, particularly in unileaflet valves. Intrinsic cuspal calcification was present in 66% of the unileaflet tricuspid, 88% unileaflet mitral, and 25% porcine tricuspid valves. Neither cuspal tearing nor perforations were found. However, cuspal stretching and redundancy of the mobile cusp was present in six tricuspid, seven mitral unileaflet valves, and no porcine valves. Gross pericardial redundancy correlated with the microscopic appearance of distorted and separated collagen bundles. These findings suggest that multiple modes of primary tissue failure may limit the durability of this unileaflet pericardial valve.

Aortic valve replacement was performed in 912 consecutive patients from January, 1972, to January, 1983. The 616 male and 296 female patients, whose ages ranged from 16 to 95 years (mean 60.6 years and median 63 years), received 663 bioprosthetic valves and 249 tilting disc valves. A higher incidence of Functional Class IV heart disease and ascending aortic aneurysms was noted in the group receiving the tilting disc valve. Six hundred fifty-seven patients had primarily aortic stenosis and 255 had primarily aortic regurgitation. Associated procedures were done in 308 patients (33%): 233 had coronary bypass grafting, 46 had replacement of ascending aortic aneurysms, and 29 had miscellaneous procedures. The overall operative mortality was 6.4% (59/912). The operative mortality was 4.5% (29/640) for isolated aortic valve replacement, 4.2% (21/233) for valve replacement plus coronary bypass, and 17% (8/46) for valve replacement plus replacement of an ascending aortic aneurysm. The mortality was 4.2% (20/663) for the group receiving bioprostheses and 12.4% (31/249) for those receiving tilting disc valves. The operative mortality for 1983 for all aortic valve replacement procedures was 2.1%; for isolated valve replacement, 1%; for valve replacement plus coronary bypass, 4.4%; and for valve replacement plus aortic aneurysm replacement, 0%. The long-term follow-up was analyzed as of Jan. 1, 1984, so that there was a minimum follow-up of 12 months (mean 55 months and median 51 months). The actuarial survival rate at 108 months for all patients was 67% +/- 2%; for valve replacement alone, 71% +/- 3%; for valve replacement plus coronary bypass, 58% +/- 7%; for valve replacement plus ascending aortic aneurysm replacement, 45% +/- 10%; for aortic stenosis, 70% +/- 3%; for aortic regurgitation, 61% +/- 4%; for Functional Classes I to III, 77% +/- 3%; for Class IV, 53% +/- 4%; for age less than 63 years, 75% +/- 3%; and for age greater than 63 years, 57% +/- 4%. At 108 months, the probability of freedom from thromboembolism was 85% +/- 3% after bioprosthetic valve replacement and 83% +/- 3% after replacement with a tilting disc valve (p = NS). The probability of freedom from hemorrhage at 108 months was 98.6% +/- 7% for the bioprosthetic valve group and 89% +/- 2% for the tilting disc valve group (p less than 0.001). The valve thrombosis rate was 0.34% per patient-year for the tilting disc valves and 0.07% per patient-year for the bioprostheses.(ABSTRACT TRUNCATED AT 400 WORDS)

A consecutive series of 706 mitral valve replacements was performed from January, 1972, to January, 1984. The follow-up ranged from 6 to 150 months with a mean of 50 and a median of 43 months. Seven percent (50) of the patient were lost to follow-up. There were 243 men and 463 women, whose ages ranged from 17 to 86 years (mean 58). A porcine bioprosthetic valve was implanted in 528 patients (514 Hancock and 14 Carpentier-Edwards valves) and a prosthetic disc valve in 178 patients (102 standard disc Björk-Shiley, 34 Beall, and 42 Harken disc valves). Seven patients were in Functional Class II, 325 in Class III, and 374 in Class IV. A concomitant operative procedure was performed in 253 of the 706 patients (36%). Mitral regurgitation was the primary hemodynamic lesion in 363 and mitral stenosis in 343. Operative mortality figures were as follows: 77 of 706 (11%) for the overall group, 34 of 453 (7.5%) for isolated mitral valve replacement, 30 of 169 (17.5%, p = 0.001) for mitral replacement plus coronary bypass, 49 of 528 (9%) for the bioprosthetic valve group, and 28 of 178 (16%) for the prosthetic disc valve group (p = 0.01). After the operation, 262 patients were in Functional Class I, 99 in Class II, and 18 in Class III. The long-term survival rate was significantly lower in patients who had an associated procedure (45% +/- 6%), who had mitral regurgitation rather than mitral stenosis (53% +/- 5% versus 67% +/- 4%) (p = 0.002), who were in Functional Class IV rather than Classes I to III (51% +/- 4% versus 70% +/- 4%) (p = 0.001), and who received a prosthetic disc valve rather than a bioprosthesis (40% +/- 6% versus 67% +/- 4%) (p = 0.001). Thromboembolic rates were significantly higher with prosthetic valves than with bioprosthetic valves (4.6% +/- 0.22% versus 2.4% +/- 0.5% per patient-year of follow-up), and the incidence of anticoagulant-related hemorrhage was significantly higher in the prosthetic valve group (1.65% versus 0.43% per patient-year). Primary valve dysfunction was significantly more common in the bioprostheses (1.23% versus 0.40% per patient-year).(ABSTRACT TRUNCATED AT 400 WORDS)

The Hancock modified-orifice porcine valve was fabricated as a result of documented obstruction of the Hancock standard porcine valve in small sizes related to the retained muscle bar of the right coronary cusp. We implanted the first clinical Hancock modified-orifice valve in 1976, and have used this valve for aortic valve replacement to the present time. This analysis compares and contrasts the clinical performance of 401 Hancock standard and 385 Hancock modified-orifice valves over a period of 10 years. Statistical significance in actuarial curves at 120 months was noted in long-term survival and thromboemboli. There was a slightly smaller amount of structural valve degeneration and incidence of reoperation with the modified-orifice valve compared with the standard valve. The Hancock modified-orifice valve has proven to be a satisfactory aortic valve replacement device, and its complex fabrication has withstood the test of time.

The Hancock porcine valve was the first commercially available biologic heart valve and has been in continuous use at the Brigham and Women's Hospital since January 1972. Through December 1987 we implanted 1678 valves in 1533 patients (885 male; 648 female; 17 to 95 years of age, with a mean of 60 years). There were 825 aortic valve replacements (AVR), 562 isolated mitral valve replacements (MVR), and 146 aortic mitral replacements (DVR). Ninety-four per cent of the patients were functional class III or IV. Associated coronary bypass was done in 25% of patients. Four per cent of patients were lost to follow up during a 1- to 16-year period with a mean of 6 years. Morbidity and mortality rates on a actuarial basis were calculated 10 and 15 years after operation for AVR, MVR, and DVR. The data indicates that the probability of reoperation for structural valve failure is quite reasonable as of 10 years, but from 10 to 15 years the numbers sharply fall off so that the probable effective life of the valve is 10 years. However in the elderly age group (equal to or greater than 70 years of age) the incidence of structural valve degeneration is markedly diminished, making this an ideal valve substitute for the elderly. It is also an ideal valve substitute in any patient who has a contraindication to long-term anticoagulation because of current medical or surgical problems.

Infective endocarditis, both in the native and prosthetic valve, presents a tremendous challenge to the cardiologist and cardiovascular surgeon, as well as the infection specialist. The timing of surgery is critical but it would appear that aggressive surgical intervention is indicated when there is persistent sepsis, continuing congestive heart failure, signs of nonfatal emboli, or in association with certain organisms such as staphylococcus, pseudomonas, or fungal organisms. Cardiac catheterization would not appear to add greatly to the diagnosis except to document the presence of coronary artery disease. The risk of surgery in patients with no annular abscess is low but the recurrence rate tends to be highly dependent on the organism. Similarly, patients who have annular abscesses tend to provide the greatest challenge for the surgeon and despite the use of newer prosthetic and biological prostheses and an overall more aggressive approach, this pathological entity, particularly in conjunction with prosthetic valve endocarditis, has a high mortality and a high recurrence rate.

From January 1, 1972, to January 1, 1981, 1282 consecutive valve replacements were performed at the Peter Bent Brigham Hospital. Fifty-eight of these (4.5%) were rereplacements: 14 for prosthetic valve subacute bacterial endocarditis (SBE), 29 for primary valve dysfunction (PVD) and 15 for perivalvular leak (PVL). Aortic rereplacement was done in 27 patients (eight for SBE, 10 for PVD and nine for PVL) and mitral rereplacement in 31 patients (six for SBE, 19 for PVD and six for PVL). Twenty-six patients were in New York Heart Association functional class III and 32 were in class IV. Ten class IV patients underwent emergency valve replacement (three for SBE, two for PVD and five for PVL). The overall in-hospital mortality rate for valve rereplacement was 14% (eight of 58 patients). For mitral valve rereplacement it was 13% (four of 31), compared with 6.4% (19 of 295) for initial mitral valve replacement. For aortic valve rereplacement, the mortality rate was 15% (four of 27), compared with 5.2% (23 of 440) for initial aortic valve replacement. The cause of death was low cardiac output in six patients, hemorrhage in one patient and sepsis in one patient. All of the patients who died were in functional class IV (p = 0.018). The in-hospital risk for rereplacement of a dysfunctional aortic or mitral valve is no different from that for primary valve replacement unless the patient deteriorates to class IV and requires an emergent operation.

The debate between reconstructive versus replacement operations for the diseased mitral valve has taken on new importance as the late results for survival, thromboembolic phenomena and incidence of reoperation from a variety of prosthetic and bioprosthetic cardiac valves have now become available. Three series of patients at the Brigham and Women's Hospital from 1972-84, representing 120 patients undergoing open mitral valve reconstruction for mitral stenosis, 348 patients undergoing mitral valve replacement for mitral stenosis, and 363 patients undergoing mitral valve replacement for mitral valve regurgitation are presented. The operative mortality in the reconstruction group was 0, there were 5 late deaths, all non-cardiac, 9 patients had a thromboembolism (1.8%/pt year), and 9 patients required reoperation (1.7%/pt year). For those who had mitral valve replacement for mitral stenosis the operative mortality was 10%, 6% for isolated replacement, 20% if this included a coronary artery bypass. At 9 years the long-term survival was 68 +/- 4%, freedom from thromboembolism 80 +/- 4%, and freedom from valve dysfunction 87 +/- 4%. In the replacement group for mitral regurgitation operative mortality was 11%, 20% with coronary artery bypass. Operative survival was 53 +/- 5% at 9 years, freedom from thromboembolism was 87 +/- 3%, and freedom from valve dysfunction was 91 +/- 4%.

Ten patients underwent mitral valve re-replacement for the third to sixth time through a right thoracotomy using one-lung anesthesia, femorofemoral bypass, profound systemic hypothermia, and low-flow perfusion without aortic cross-clamping or cardioplegia. The indications for this approach were previous mediastinitis, severe right ventricular hypertension with multiple previous sternotomies, intact coronary artery bypass graft, or previous aortic valve replacement. There was 1 operative death, which was due to end-stage pulmonary hypertension and intractable right heart failure. Blood loss was minimal, and there was no major postoperative morbidity in the 9 surviving patients except for supraventricular arrhythmias.

The fabrication of the Hancock modified-orifice valve raised questions about its long-term durability. Since 1976, 315 patients (206 male, 109 female) with a mean age of 63 years underwent aortic valve replacement with 21 mm (n = 120), 23 mm (n = 153), 25 mm (n = 36), and 27 mm (n = 6) Hancock modified-orifice valves. There were five operative deaths (1.6% mortality). Two hundred sixty-two patients are alive 2 to 117 (mean 53) months postoperatively. Actuarial probability of survival at 96 months was 78% +/- 3%. Two hundred twenty-two survivors are in Functional Class I or II. Forty-three patients have had valve-related complications: thromboembolism in 25 (1.9%/pt-yr), primary valve dysfunction in eight (0.6%/pt-yr), and endocarditis in 11 (0.8%/pt-yr). Twelve patients have required reoperation (0.8%/pt-yr) for primary valve dysfunction (four patients), for endocarditis (five patients), and for perivalvular leak (three patients). At 96 months the actuarial probability of freedom from thromboembolism was 87% +/- 3%, from primary valve dysfunction 97% +/- 2%, and from endocarditis 92% +/- 3%. The probability of freedom from all valve-related complications was 78% +/- 4% and from reoperation 94% +/- 2%. The performance of this prosthesis justifies its continued use for aortic valve replacement.

The degree of progressive inward deflection of the stent posts ("stent creep") during function of Hancock standard orifice porcine aortic valve bioprostheses is unknown. The present investigation determines, using a quantitative geometric analysis of clinically removed bioprostheses, the contribution of stent creep to progressive reduction in the outflow orifice area of these valves. Fifty-four Hancock standard orifice porcine aortic valve bioprostheses obtained at reoperation or at autopsy of 50 patients were studied; 47 of these were removed more than 21 months postoperatively. The projected geometric outflow orifice area of each prosthesis was planimetrically measured. To compare prostheses through the entire range of available sizes, this measured area was divided by that of an unimplanted valve of the same size to calculate a ratio designated the "normalized outflow area ratio" (NOAR). Thus, by definition, for all unimplanted standards, NOAR was 1.00. In 7 prostheses in place for less than 1 month, the NOAR was 1.00 +/- 0.03 (mean +/- standard deviation). In 47 prostheses removed 21 to 126 months postoperative, the NOAR was 0.91 +/- 0.08. The relation between NOAR and duration of function determined by linear regression was NOAR = 0.955 - 4.560 X 10(-4) X Duration (in months). The minimum NOAR found was 0.74; the NOAR was less than 0.80 in 4 prostheses (8% of long-term valves). Thus, stent creep is usually not prominent after long-term function of Hancock standard orifice procine bioprostheses and suggests that clinically important progressive reduction of the geometric outflow orifice is infrequent.