PubMed Health⌕ Search

Biomedical subjects

W W Angell

Publications and source records attributed to W W Angell.

At least 19 recordsLinked to original sources
PubMed1995

Bioprosthetic valve longevity in the elderly: an 18-year longitudinal study.

The issue of bioprosthetic valve durability has become of critical importance as the number of elderly patients requiring valve operation has continued to increase. Our previous study showed bioprosthetic valve durability to be in excess of 83% at 13 years for patients 70 years of age and older at the time of implantation. There is limited follow-up data in the literature beyond this time point, however. Accordingly a retrospective analysis was conducted of all patients with bioprosthetic valves who were 70 years of age and over at the time of implantation. From September 1974 to April 1994, 1007 patients 70 years of age and over underwent valve replacement using a porcine bioprosthesis. The patients ranged in age from 70 to 104 years (mean, 75.6 +/- 4.3 years). There were 549 men (54.5%) and 458 women (45.5%). Preoperatively 98.8% of the patients were in New York Heart Association functional class III or IV. Operation was performed as an emergency in 66 patients (6.6%). The hospital mortality was 10.9% (110 patients), with 897 hospital survivors. There were 961 valves at risk. Follow-up extended from 1 month to 18.8 years (mean, 56.6 months). The cumulative follow-up is 4232.3 patient-years. A total of 31 valves failed, 12 in the aortic position and 19 in the mitral position (p < 0.0024). The causes of valve failure have included structural deterioration (16 valves), prosthetic endocarditis (7 valves), nonstructural dysfunction (5 valves), prosthetic thrombosis (1 valve), and other (2 valves).(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1995

Influence of coronary artery disease on structural deterioration of porcine bioprostheses.

The number of patients undergoing valve replacement and concomitant coronary artery bypass grafting (CABG) is increasing. To further evaluate the indications for the use of the porcine bioprosthesis, this retrospective comparative analysis of valve structural deterioration was conducted in patients with and without concomitant CABG. From September 1974 to October 1993, 1,567 patients underwent valve replacement using a porcine xenograft. The series was divided into two groups: patients with isolated valve replacement (VR; n = 876) and those with VR and CABG (VR + CABG; n = 691). Aortic valve replacement was performed in 938 patients, mitral valve in 518, tricuspid in 2, and multiple valve replacement in 109 patients. The mean age for the series was 70.7 years (range, 50 to 104 years). The hospital mortality was 8.8% (138 patients). The hospital mortality for the VR group was 7.4% (65 deaths) and the VR + CABG group, 10.6% (73 deaths) p = 0.0365. There were 1,429 patients discharged from the hospital with 1,489 valves at risk. Follow-up extended from 1 month to 17.9 years with a mean of 66.9 months and was 98.3% complete. The cumulative follow-up was 7,927.1 patient-years. Structural deterioration was found to be significantly greater in the VR group for the age category 50 to 59 years (p = 0.0121) and the 60 to 69 years (p = 0.0230). No significant difference in the rate of structural deterioration was found for the two groups for the age category 70 years and older.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMed1995

Sequential internal mammary artery grafting: a viable alternative in myocardial revascularization.

The internal mammary artery has become the conduit of choice in myocardial revascularization. The expanded use of this ideal conduit for sequential grafting has enhanced its application. Between March 1985 and June 1993, 245 consecutive patients underwent revascularization of the myocardium with internal mammary artery bypass grafts with at least one sequential anastomosis. There were 186 men and 59 women, with a mean age of 65.1 (range 40-82) years. Unstable angina was present in 141 patients (57.6%) and 36 patients (14.7%) had left main coronary artery stenosis (> 50%). Before surgery, five patients (2.0%) were in New York Heart Association (NYHA) class II, 113 (46.1%) in class III, and 127 (51.8%) in class IV. There were a total of 1041 coronary artery grafts, mean 4.2 (range 2-7) grafts per patient and 528 sequential left internal mammary artery anastomoses, mean 2.2 per patient. Hospital mortality rate was 2.4% (six patients). Almost two-thirds of the patients experienced no hospital complications. The most frequent complication included arrhythmia in 36 patients (14.7%), respiratory insufficiency in 15 (6.1)% and temporary left phrenic nerve palsy in ten (4.1%). Mean follow-up was 37.0 (range 1-94.2) months. The mean(s.e.m.) actuarial survival rate for patients discharged from hospital was 94.8(1.6)% at 36 months and 82.4(5.0)% at 72 months. At follow-up of 222 patients, 185 (83.3%) were symptom-free in NYHA class I and 27(12.2%) were in class II. Though technically demanding, multiple sequential internal mammary artery grafting is feasible and can be accomplished with low hospital mortality and morbidity.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Aortic valve replacement: procedure of choice in elderly patients with aortic stenosis.

Aortic valve replacement is the treatment of choice for elderly patients with aortic stenosis. It can be accomplished with excellent immediate and long-term results with significant functional improvement. Unfortunately, the literature is replete with enthusiastic reports of aortic catheter balloon valvotomy. Initial findings were controversial and the long-term results have been poor due to early valve restenosis. A retrospective analysis of our surgical experience with aortic valve replacement in the elderly seems appropriate in an effort to put this issue in proper perspective. From January 1973 to June 1993, 200 consecutive patients 70 years of age and older with severe aortic stenosis underwent surgical correction. There were 105 men (52.5%) and 95 women (47.5%), with a mean age of 76.2 years (range 70 to 89). Preoperatively, 195 patients (97.5%) were in New York Heart Association (NYHA) Class III or IV. Over one half (61.0%) of the patients experienced no hospital complications. The hospital mortality was 9.0% (18 patients). This included 14 patients in NYHA Class IV. The mean follow-up was 69.3 months and ranged from 1 to 215 months. The actuarial survival for 182 patients discharged from the hospital was 70.8% +/- 4.0% (SEM) at 72 months (73 patients at risk) and 35.2% +/- 5.4% at 144 months (20 patients at risk). Considering the advanced age and preoperative functional classification in this patient group, the results of aortic valve replacement have been excellent. The survival of patients discharged from the hospital compares favorably with a normal population matched for age and sex. The results of aortic balloon valvotomy have been disappointing.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Ischemic mitral valve disease: classification and systemic approach to management.

One hundred sixty-nine consecutive patients with coronary artery disease and mitral valve pathology operated during the past 5 years were reviewed (98% follow-up). Eighty-seven patients underwent mitral valve repair and 82 mitral valve replacement with concomitant coronary artery bypass grafting (number of AV grafts = 3). An analysis of these patients (age range 48 to 92 [mean 69]) and a classification based on anatomic pathology of the mitral apparatus is presented. Flexible ring annuloplasty was utilized in all repairs and chordal-sparing techniques in all valve replacements. There was equal mortality for replacement and repair in this subset of high risk patients. Structural valve dysfunction of repaired valves was more common (5/81 [6.0]) than primary tissue valve failure after mitral valve replacement (0 patients).

Aged↗
PubMed1993

Implantation of the unstented bioprosthetic aortic root: an improved method.

The problem of early onset aortic insufficiency as seen with the scalloped, subcoronary homograft aortic valve replacement is reduced with the use of a total root replacement. In addition, the naturally competent aortic root is more durable. From September 1985 to April 1991, 26 consecutive patients underwent aortic root replacement with 10 autografts, 14 homografts, and 2 xenografts using a modified implantation method. Twenty-five patients were discharged from the hospital. This partial inclusion root technique for implanting unstented valves in the aortic position decreases the probability of early failure secondary to technical malalignment at the time of implantation. In contrast to total root replacement, it avoids the need to destroy the recipient aortic root. A longitudinal aortotomy is performed to the aortic annulus in the mid-portion of the noncoronary sinus. The proximal suture line is interrupted with the valve oriented in the anatomical position. Circumferential running monofilament side-to-side anastomoses approximate the donor coronary ostia to the recipient. A running medial and lateral posterior suture line to the lateral superior portions of the aortotomy completes the integrity of the anterior wall of the implantation. One autograft attempt failed and one homograft patient died postoperatively. Follow-up ranges from 1 to 6 years in 24 patients. Postoperative aortic insufficiency was significant in one case due to inappropriate sizing of the proximal aortic suture line. There has been no evidence of progressive aortic insufficiency detected by the early onset of diastolic murmurs or echocardiograms as was our previous experience with the scalloped subcoronary method.

Adolescent↗
PubMed1993

Partial inclusion aortic root replacement with the pulmonary autograft valve.

The expanded use of autografts for aortic valve replacement has focused attention on developing an improved implantation technique with the aim of reducing the incidence of early insufficiency. While the technique for total root replacement with nonstented tissue valves is a proven and established method, it is, however, not generally accepted for use in all clinical circumstances. Through the use of a partial inclusion technique, we propose to modify the standard method of extended aortic root replacement and pedicle coronary implantation. This approach also has the advantage of leaving the recipient aortic root intact. Unlike traditional scalloped subcoronary homograft implantation, it does not enclose the transplanted valve totally within the recipient aorta. Thus, there is preservation of the patient's aorta without distortion of the transplanted valve which occurs when it is forced completely into the closed recipient aortic root. While this partial inclusion method is not as simple as total root replacement, preservation of the recipient root is generally more acceptable to implanting surgeons. Either perfection of this proposed method or the acceptance of a traditional extended aortic root replacement will result in correction of the persistent problem of early aortic insufficiency following the use of autograft valves. Decreasing valve incompetence will have the desired effect of increasing the indication for the use of autografts for aortic valve replacement in young patients.

Anastomosis, Surgical↗
PubMed1992

Universal method for insertion of unstented aortic autografts, homografts, and xenografts.

Since the advent of homograft aortic valve replacement surgery in the early 1960s, this procedure has been plagued by early aortic insufficiency. This problem has not been observed with total aortic root replacement. From September 1985 to April 1991, a modified method was used in 25 of 39 consecutive patients having aortic root replacement--seven having autografts, 30 having homografts, and two having xenografts. This technique is a new approach for implanting unstented valves in the aortic position. It decreases the probability of early failure resulting from technical malalignment of the valve during implantation. Further, it avoids the need to destroy the recipient aortic root. Whether the valve being used is an autograft, homograft, or xenograft, this method standardizes the insertion technique regardless of the anatomy or disease. Salient features of the method include the following: a longitudinal aortotomy to the aortic anulus in the midportion of the noncoronary sinus; a proximal interrupted suture line with the valve oriented in the anatomic position; and circumferential running monofilament side-to-side approximation of the donor coronary ostia to the recipient coronary ostia. The two anterior commissures are left untethered by nonclosure of the recipient aortotomy. Preliminary results have been impressive, with follow-up ranging from 1 to 3 years in 30 of these patients. Postoperative aortic insufficiency was significant in only two cases. There has been no progression of aortic insufficiency detectable by diastolic murmur or echocardiogram. Late complications have been minimal, and the overall clinical results have been excellent.

Adolescent↗
PubMed1991

Bioprosthetic valve durability in the elderly: the second decade.

With an increasing number of elderly patients requiring cardiac valve surgery, the topic of bioprosthetic durability becomes critically important. Previous reports have shown expected survival of bioprosthetic valves to be in excess of 95% at 9 years. However, primary tissue failure appears to accelerate at the end of the first decade and there is limited data into the second decade. With this in mind, we proceeded to analyze all bioprosthetic valves implanted in patients 70 years of age and older. From September 1974 to December 1990, 781 patients underwent valve replacement using a bioprosthesis. Ages ranged from 70 to 88 years with a mean of 75.1. There were 423 males (54.2%) and 358 females (45.8%). Preoperatively, 99.0% of the patients were in either New York Heart Association functional Class III or IV. Fifty-nine patients (7.6%) were done as emergencies. Six hundred ninety-four patients left the hospital (30-day overall mortality 11.1%). In this cohort, there were 733 valves at risk. Follow-up extended from 1 to 186.0 months with a mean of 52.9, which resulted in 3,059.9 patient-years of cumulative follow-up. Bioprosthetic Survival: A total of 23 valves failed in the series; 15 primary tissue failures, seven from endocarditis, and one perivalvular leak. Actuarial survival at 7 years was 94.5% +/- 1.4% standard error of the mean (SEM; 168 valves at risk) and at 13 years, 83.7% +/- 4.8% SEM (11 valves at risk). This analysis provides further documentation of the long-term favorable durability of the bioprosthesis when utilized in patients 70 years of age and over.

Actuarial Analysis↗
PubMed1991

Effect of stent mounting on tissue valves for aortic valve replacement.

Stent mounting of homograft valves was first reported by our group in 1968. Since then, there has been question as to whether or not stent mounting of bioprostheses adversely affects the incidence of structural deterioration in aortic valve replacement. Between November 1967 and July 1988, 571 consecutive patients underwent valve replacement with a stented or unstented homograft. There were 351 men (61.5%) and 220 women (38.5%). The mean age of the group was 49.2 years (range 18 to 79 years). Five hundred thirty-four patients left the hospital (30-day overall mortality 6.5%). Follow-up extends from 6 months to 22 years with a mean of 7.6 years. The cumulative follow-up for the series was 4,095.9 patient-years. Hospital mortality, early technical failure, and prosthetic valve endocarditis were considered censoring events and excluded from this study. Actuarial analysis revealed a significant difference (p less than 0.02) in the freedom from structural valve deterioration for unstented and stended isolated aortic valve replacement. Age (50 and under, and over 50) does not appear to be a factor in structural deterioration in unstented homografts but does influence the rate of failure in stented homografts (p less than 0.05). These results clearly indicate that stent mounting adversely affects tissue valve durability with aortic valve replacement. Moreover, age correlates with structural deterioration if valves are stented and does not if they are unstented. Based on these results, the use of unstented bioprostheses should be reevaluated, along with the design of porcine valve stents.

Adolescent↗
PubMed1991

Unstented and partial stented bioprostheses for aortic valve replacement--up to 6 years of follow-up.

Since January 8, 1985, three different designs of unstented (type A, n = 9) and partial stented (type B, n = 4; and type C, n = 3) glutaraldehyde preserved porcine aortic valves were used for aortic valve replacement in 16 patients with acquired aortic valve lesions. Type A and type B prostheses were implanted using a two suture row technique. In type C prostheses, only a single suture row was necessary for implantation, facilitating surgery considerably. In all patients, the fully flexible commissures of the bioprostheses were secured to the aortic wall of the recipient. There was no hospital mortality. Two patients with type A bioprostheses died due to noncardiac causes, 4 and 24 months postoperatively. One bioprosthesis in this group had to be replaced after 3 months because of insufficiency. Serial Doppler echocardiographic studies were performed up to 6 years after implantation. No significant leaflet calcification was observed. In three type A bioprostheses, a mild insufficiency without progression was recorded. The latest mean/peak transprosthetic pressure gradients were: type A: 6 +/- 4 mmHg/12 +/- 6 mmHg; type B: 6 +/- 3 mmHg/14 +/- 5 mmHg; and type C: 11 +/- 5 mmHg/18 +/- 8 mmHg. The functional results of the type A and type B bioprostheses have proven to be satisfactory. The slightly higher pressure gradients in patients with a type C bioprosthesis give rise to further refinements of its design. These results confirm the usefulness of imitating normal anatomy by using unstented or partial stented bioprostheses.

Adult↗
PubMed1989

Twenty-year comparison of the human allograft and porcine xenograft.

This study compares a retrospective consecutive series of human allografts and concurrent porcine xenografts implanted over a 10-year interval. There were 571 allograft valves and 1,351 xenograft valves implanted in the aortic and mitral position with mean follow-up of 12.8 years for the allografts and 6.2 years for the xenografts. This study compares the incidence of structural deterioration over long-term follow-up. We found that there was no significant difference between four manufacturers of porcine xenografts, in spite of substantial differences in processing techniques. We found that there was a significant difference in allografts that were premounted on stents as compared with allografts that were not premounted on stents for aortic valve replacement. We found that there was no significant difference between allografts for aortic valve replacement that were not premounted on stents and porcine xenografts implanted in the aortic position. These findings are in marked contrast to those of other reported series with the use of allograft valves.

Animals↗
PubMed1989

Durability of the viable aortic allograft.

Of 581 aortic allografts implanted since 1967, 421 were analyzed for structural deterioration. This series is unique in that it includes patients from the early allograft experience. All allografts were cleanly procured, antibiotic sterilized, and either stored at 4 degrees C for up to 8 weeks or frozen to liquid nitrogen temperatures with cryopreservation to preserve the viable cusp fibroblasts. There were 25 frozen mounted aortic valves with a median time to valve failure of 12.1 years, which was not significantly different from the 12.5-year period for 114 fresh free-sewn aortic valves. The median time to valve failure was 6.6 years for 90 fresh-mounted aortic valves and 8.6 years for 192 fresh-mounted mitral valves (p = 0.05). The difference between all mounted and unmounted grafts was significant (p = 0.0001). In all groups, viable fibroblasts were present in specimens explanted up to 5 years after the operation. All specimens returned after more than 10 years were almost totally acellular. Evidence of increased collagen, suggesting that the fibroblasts survive implantation and then gradually die, was present in all specimens. This series suggests that durability of the unmounted viable allograft for aortic valve replacement is greater than for other types of tissue valves. Pre-mounted allografts for aortic or mitral valve replacement have a median survival of 8 years and are not more durable than other tissue valves.

Aortic Valve↗
PubMed1988

The cryopreserved homograft valve in the pulmonary position: early results and technical considerations.

Since September, 1985, 20 patients have undergone implantation of a homograft valve in the pulmonary position (16 pulmonary, 4 aortic). There were 11 primary operations and 9 reoperations. In 7 of 11 primary operations the homograft valve was utilized as a composite conduit with a short Dacron extension. In four of five reoperations for a failed porcine valved conduit, a composite homograft conduit was used. Four patients underwent implantation of a free homograft in a previously repaired right ventricular outflow tract (RVOT). Age ranged from 15 days to 22 years. There was one operative death (5%), a seven-week-old infant with truncus arteriosus. Long-term follow-up ranges from 1 to 30 months. Clinical performance has been satisfactory in 18 of 19 patients. One patient undergoing free implantation of a pulmonary valve in the RVOT required replacement at 18 months with a porcine valve. In this patient, pulmonary insufficiency was caused by distortion of the annulus secondary to dilatation and pulmonary hypertension. Nine of 18 survivors do not require medication. Eleven of 18 have trivial to mild pulmonary insufficiency murmurs without symptomatology. The homograft valve is extremely useful in reconstruction of the right heart, however, early insufficiency murmurs have been noted. Distortion of the valve annulus may contribute to the early onset of a benign insufficiency murmur. Residual distal obstruction or pulmonary hypertension may be a contraindication to the use of a free homograft in the orthotopic position.

Adolescent↗
PubMed1988

Long-term fate of valve cusp patches for right ventricular outflow tract reconstruction.

Six patients with tetralogy of Fallot, pulmonary atresia, or absent pulmonary valve syndrome were operated with a RVOT patch containing a single aortic allograft cusp from an adult donor. The method was based on animal work with similar patches implanted in growing puppies and proved that the single cusp functioned as an effective RV outflow valve for several weeks after surgery. Postoperative angiograms in the animals confirmed nearly completely competent valves. Sacrifice of animals at 3 months documented that the allograft tissue was flexible without early deterioration or calcification. Clinical application of this method raised several questions regarding the procedure, its efficacy, and subsequent fate of the allograft valve in children requiring RVOT reconstruction. There were six children age 19 months to 10 years who required division of the pulmonary valve annulus to relieve pulmonary outflow obstruction or with absent pulmonary valve syndrome and compromised airways from pulmonary insufficiency. One patient had a positive culture from the valve and required immediate removal of the infected allograft. Patients had clinically competent pulmonary valves immediately after surgery with decreased right ventricular systolic and end-diastolic pressures when compared with patients in whom nonvalve patches were inserted. All patients had some degree of pulmonary insufficiency, but no symptoms. Follow-up up of five patients available 4 to 6 years after surgery revealed no patients with stenosis of the valve cusps, although two patients have severe, one moderate, and two mild pulmonary insufficiency. We conclude that a patch containing a single adult allograft valve cusp should be considered for all patients requiring reconstruction of the RVOT, particularly if RV overload is expected to compromise the immediate postoperative result.

Animals↗
PubMed1988

Comparison of Hancock I and Hancock II bioprostheses.

The Hancock II bioprosthesis was developed in order to provide the advantageous low pressure fixation, improved delrin stent design, and anticalcification treatment. These changes were made 6 years ago after 10 years of experience with the high pressure fixed rigid implantation ring and polypropylene stent used in the Hancock I valve. In 1983, based on our own experience with low pressure fixed valves in 76 patients, we began early clinical trials with the Hancock II valve. All valves were studied postoperatively by intraoperative catheterization and followed up with postoperative echocardiograms for measurement of valve gradients and areas. This series of 104 patients with Hancock II valves was then compared retrospectively with 119 patients receiving Hancock I valves from 1975 to 1983. A comparison of mortality, thromboembolism, and hemorrhage rates was not significantly different between groups and the valve failure incidence of Hancock I valves was an anticipated 2.34% per patient-year. There has been one primary tissue failure in the Hancock II series. This patient had fibrinous excrescences on the outflow surface of the valve in the aortic position. These nodules were compatible with an old thrombotic process of ill-defined nature. Further investigation resulted in reports of this phenomenon, which had resulted in early valve stenosis, from other centers implanting the Hancock II valve. In conclusion, the Hancock II bioprosthesis has theoretical advantages over the Hancock I in stent design, fixation pressure, and anticalcification potential. There is an unusual thrombotic process in aortic valve replacements that we have not observed in the Hancock I group or in our experience with other porcine xenografts.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗