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Biomedical subjects

W W Angell

Publications and source records attributed to W W Angell.

At least 37 records · Page 2Linked to original sources
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↗
PubMed1988

Experience with Damus procedure.

Sixteen patients with complex cyanotic congenital heart disease underwent an operation involving the use of the aorta and the main pulmonary artery as the egress for systemic arterial blood flow (the Damus-Kaye-Stansell operation, modified as discussed). The indication for this approach was either preoperative aortic outlet obstruction or likelihood that the repair would produce such obstruction. A modification of the original technique is introduced that involves transection of both great arteries, anastomosis of the contiguous aortic and pulmonic walls, and connection of the distal aorta to the perimeter of the new (bivalved) great artery. Eleven of the 16 patients survived operation: six of six who underwent a concurrent Fontan operation, four of six who underwent a concurrent right-ventricle-to-pulmonary-artery-conduit procedure, and one of four who underwent a concurrent systemic-pulmonary shunt procedure. Postoperative status in the 11 survivors is good: one patient has a gradient from the left ventricle to the aorta, 10 of 11 have little or no aortic regurgitation, and the remaining patients have a normal physiological status. We conclude that the Damus procedure is a useful addition to the surgical armamentarium for treatment of certain types of cyanotic congenital heart disease.

Angiography↗
PubMed1987

A comparison of replacement and reconstruction in patients with mitral regurgitation.

The factors that make mitral reconstruction an attractive alternative to valve replacement are increased anatomical valve orifice, preservation of the valvular apparatus, improved longevity over porcine xenografts, and no requirement for long-term anticoagulation. In our experience the majority of patients with mitral regurgitation have degenerative valve disease. This comparative series of patients operated on over a 10 year interval includes 72 with replacement and 112 with reconstruction. The average cross-clamp times were 69 minutes for reconstruction and 44 minutes for replacement. The hospital mortalities were 3.6% and 18.1%, respectively. Postoperative valve areas as determined by Doppler echocardiography were 2.69 cm2 for replacement and 2.67 cm2 for reconstruction (p = 0.9). The valve failure rate was 2.0% per patient-year for reconstruction and there were no failures in the replacement group. The reoperation incidence for reconstruction was 20% at 10 years. The remaining patients, although clinically well, had varying degrees of stable, nonprogressive mitral regurgitation. Forty-five percent had mild to trivial regurgitation detectable by echocardiographic studies. The decision between mitral valve reconstruction and mitral valve replacement remains a highly controversial issue. The failure of our data to demonstrate superior valve function for patients with mitral regurgitation undergoing valve reconstruction suggests a need for careful analysis of reconstruction with respect to effective valve orifice and incidence of regurgitation.

Bioprosthesis↗
PubMed1987

Long-term follow-up of viable frozen aortic homografts. A viable homograft valve bank.

There is currently a renewed interest in the use of both fresh and commercially available frozen homograft valves for children and young adults. This has prompted us to review a series of 32 patients who received frozen homograft valves for aortic replacement between 1973 and 1975. The cryogenic technique evolved to include the use of selected antibiotics and equilibrated dimethyl sulfoxide solution to freeze homografts at a rate of 1 degrees C per minute to liquid nitrogen temperatures of -196 degrees C. Histologic sections of experimental frozen valves explanted 6 months postoperatively revealed the presence of viable donor cells, and tissue culture demonstrated the reproductive capacity of cusp fibroblasts. Of the 32 frozen viable homografts implanted in this series, 23 were inserted as free-sewn aortic replacements and nine were premounted on stents before implantation in the aortic position. There were two operative deaths, and three valves failed as a result of the technical problems of mounting in one patient and surgical insertion of a free graft in two patients. Of the 22 patients who remained at long-term risk, 13% with free-sewn grafts and 57% with premounted valves underwent reoperation for valve failure. After 10 years of follow-up, 15 (68%) of these patients, 12 (80%) with free-sewn and three (43%) with premounted valves, are alive with their original valve in place. Actuarial analysis shows that 58% of the 32 valves implanted are functional at the beginning of the eleventh year. There have been six late deaths resulting in an overall actuarial patient survival rate of 79% at 10 years and 69% after 13 years. These clinical results are believed to add support to our current application of the frozen homograft in selected patients.

Adult↗
PubMed1982

Twelve-year experience with glutaraldehyde-preserved porcine xenografts.

Three hundred fifty-two patients underwent aortic (AVR) or mitral (MVR) valve replacement with a glutaraldehyde-preserved porcine xenograft from 1970 to 1980. Analysis of this series revealed the following information: hospital mortality, 11.6% (41/352); late mortality, 5.5% per patient-year (60/1,090.7); actuarial 5 year survival rate, 70%; incidence of thromboembolism and hemorrhage, 1.4% per patient-year (15/1,090.7); incidence of spontaneous degeneration, 1.1% per patient-year (12/1,090.7); and transvalvular gradient. AVR 16 mm Hg and MVR 4.6 mm Hg. These results compare favorably with results from other porcine xenograft series and with those reported for prosthetic valves. There is no apparent difference in the type of xenograft used with the exception that spontaneous degeneration occurred less frequently in mitral valves that had not undergone pressure fixation than in those that had. The use of flexible stents improved the ease of valve implantation but did not affect leaflet durability as anticipated. Calcification occurred randomly with no relationship to time of implantation. Reoperation was for spontaneous valve deterioration by calcification or collagen degeneration in 11 cases, paravalvular leak in 13 cases, and implantation of an undersized valve in four cases; there was one reoperation for infection. Results support the continued use of porcine xenografts and suggest that improved manufacturing techniques will reduce the incidence of spontaneous, sterile deterioration, which is the only serious drawback to routine use of the porcine xenograft.

Aged↗
PubMed1979

The Angell-Shiley porcine xenograft.

A 4-year clinical experience with fresh allograft tissue valves prompted a trial of 0.5% buffered glutaraldehyde as a valve fixative and sterilant. Tanned allograft and porcine xenograft valves were inserted into experimental animals, and, beginning in 1970, similar valves were implanted in a series of patients now totaling 312. The clinical results are excellent. The 5-year valve-related mortality is 6% for patients who had mitral valve replacement and 16% for those with aortic valve replacement. To date, the incidence of thromboembolism is 1.3% per patient-year, and valve-related morbidity and mortality for the combined groups is 27.4%. Valve stent design has evolved from symmetrically configured metal to anatomically molded plastic. The maintenance of natural valve configuration has optimized leaflet coaptation and support, decreased tissue stress, and eliminated valve-stent dehiscence and tissue rupture seen in valves deformed to fit symmetrical stents. Stent design, controlled glutaraldehyde solutions, and fixation techniques have improved leaflet flexibility and reduced valve orifice to annulus diameter ratios, thus producing transvalvular gradients comparable to both mechanical and modified orifice tissue valves. To date, tissue failure, observed in only 1.0% (3 of 287) of patients, is the result of calcification (2 patients) and cusp rupture due to incomplete fixation (1 patient).

Adult↗
PubMed1977

Unstable angina: comparison of medical and surgical management.

Medical versus surgical treatment of unstable angina was compared in a prospective nonrandomized study of 118 patients. Acute transient ST-T wave changes were present during chest pain in all patients. Acute infarction was excluded by serial electrocardiograms and enzyme studies. All patients admitted to the coronary care unit from 1970 to 1975 who fulfilled the entry criteria were included in the study. The starting point for data evaluation was 5 days after hospital admission. Characteristics at entry were similar in 66 medically treated patients and 52 patients who had coronary bypass vein graft surgery. During a mean follow-up period of 23 months in 66 medically treated patients with unstable angina the incidence rate of nonfatal myocardial infarction was 17% and the total mortality rate 21 percent compared with respective rates of 19% and 5.8% in 52 surgically treated patients. In the surgical group 8 patients (15%) had a perioperative infarction and only 2 (4%) had a late infarction; one patient (2%) died at operation. Symptomatic improvement was observed more frequently in the surgically treated group. Sixty percent of surgically treated patients were free of angina compared with 21% of medically treated patients. Eight medically treated patients (12%) required late surgical treatment for persistent severe angina despite optimal medical management.

Angina Pectoris↗
PubMed1977

Acute myocardial infarction and ischemic injury during surgery for coronary artery disease.

The incidence of myocardial infarction, acute ischemic injury, and associated serum enzyme abnormalities has been evaluated in four operations involving the coronary circulation. The highest incidence of infarction was associated with internal mammary implantation (Vineberg procedure). There was no significant difference in the incidence of infarction, ischemic injury, or abnormal enzyme levels between patients with stable angina and those with unstable angina who had vein bypass surgery. In operations involving combined vein bypass grafting and valve replacement surgery, the incidence of abnormal serum enzyme elevations was higher than in any other procedure. The incidence of infarction and acute ischemic injury in combined operations was similar to that in other procedures but this may have been due to the difficulty in the ECG diagnosis of infarction in this group of patients, most of whom had abnormal preoperative ECGs.

Acute Disease↗
PubMed1977

The saphenous vein versus internal mammary artery as a coronary bypass graft.

Controversy persists as regards the efficacy of aortocoronary saphenous vein bypass graft (SVBG) compared to direct internal mammary artery (IMA) anastomosis. In general, the IMA graft (IMAG) is considered to be superior as regards postoperative patency. To avoid preselection bias, 74 consecutive, unselected patients with bypassable lesions of the left anterior descending artery (LAD) were randomized to undergo either SVBG or IMAG to the LAD in 1972-1974. The majority of patients had, in addition, SVBGs to other vessels. Postoperative angiograms, an average of 6 months after surgery, were obtained in two-thirds of the patients. The following observations were made: (formula: see text). In this series there is no clear advantage of the IMAG over the SVBG. The preparation of the internal mammary artery for grafting is tedious and the anastomosis more difficult to perform. The resultant flow in the internal mammary artery graft is less overall than in the SVBG. In over 400 unselected SVBGs to the LAD that have been restudied thus far in our practice, an 86% patency rate has been achieved.

Angina Pectoris↗
PubMed1977

Section of tissue or prosthetic valve. A five-year prospective, randomized comparison.

After considerable experience, controversy persists between the selection of a tissue or prosthetic valve. In order to provide a nonbiased comparison, we designed a prospective, randomized study in September of 1970. Ninety-nine consecutive patients with isolated primary single valve replacement were randomized to tissue or prosthetic valves. The Tissue Bank supplied homografts which were either mounted for mitral replacement or used as free grafts for patients with small aortic roots. Starr-Edwards clot-covered prostheses were used for comparison. There was an even distribution of patients by age, sex, valve lesion, and New York Heart Classification attesting to the accuracy of the random selection. Anticoagulants were used in 33 patients who had operative or embolic evidence of atrial cloth or else history of thromboembolism. Thirty-five patients have undergone postoperative catheterization. Causes of death and valve failure are presented on an actuarial basis. Death in the Starr-Edwards patient group was sudden or due to fabric wear with subsequent thromboembolism, hemorrhage, or infection. We conclude that the tissue valve is a better choice for valve replacement. While there is no significant functional or hemodynamic apparent difference between the tissue and prosthetic valve, there is improvement in patient morbidity and mortality rate with the use of homografts, particularly in the aortic position. The primary cause of complications in the homograft is tissue deterioration, and this problem has been markedly reduced with advent of glutaraldehyde fixation. No such advance in solving the problem of host incompatability with the prosthesis has been forthcoming.

Aorta↗
PubMed1977

Coronary artery spasm. medical management, surgical denervation, and autotransplantation.

Coronary artery spasm was induced by intravascular administration of ergonovine maleate (Ergotrate) during cardiac catheterization. In 78 patients suspected to have Prinzmetal's angina, no morbidity or death has resulted despite complete occlusive spasm in two and three coronary arteries. Typical EKG changes and akinesia of the myocardium in the distribution of the occluded vessels documented functional myocardial ischemia during spasm. The occlusive spasm is readily reversed by sublingual or intravascular nitroglycerin, and ventricular contractility returns to normal following relief of spasm. Occlusive spasm has been demonstrated in 15 patients with clinical evidence of Prinzmetal's angina. Symptoms have been effectively relieved by coronary vasodilators in 10 patients. Of the 5 patients in whom medical therapy failed, 4 were treated surgically. These 4 patients were in the intensive care unit with protracted, prolonged pain, subendocardial infarctions, and persistent failure of coronary vasodilators. Aorta-coronary bypass grafts have been combined with total cardiac denervation by autotransplantation (one patient) and total cardiac denervation by stripping of the great vessels (3 patients). Two of the patients treated by cardiac denervation died in the early postoperative period. The patient treated by autotransplantation has total relief of symptoms but persistent spasm on angiography. The angiographic demonstration of occlusive coronary spasm remains a valuable diagnostic tool to document definitively the presence of spasm. The surgical results question the value of surgical intervention in this disease.

Adult↗
PubMed1976

Acute coronary embolism complicating bacterial endocarditis: operative treatment.

A patient with bacterial endocarditis and no previous history of angina substained an acute anterolateral myocardial infarction while awaiting surgery. Selective coronary arteriography revealed a filling defect in the left anterior descending coronary artery with limited flow beyond the area of occlusion. A calcific embolus from the infected aortic valve was removed at the time of valve replacement, and the patient had an uneventful immediate postoperative course. Late postoperatively paravalvular aortic regurgitation recurred before and after a second repair.

Acute Disease↗
PubMed1975

Myocardial damage in combined valvular and coronary bypass surgery.

The incidence of perioperative myocardial infarction (MI) and acute ischemic injury was determined in 44 patients having aortic valve replacement plus aortocoronary vein grafts (AVR + CABG) and in 22 patients having mitral valve repair or replacement plus aortocoronary vein grafts (MVR + CABG). These data were correlated with aortic cross-clamp time, fibrillation time, presence of left ventricular hypertrophy, and, in selected cases, left ventricular biopsy. Perioperative MI occurred in 21% (9/44) of the AVR + CABG patients and 5% (1/22) of MVR + CABG patients. In contrast, the MI rate for isolated valve replacement was 7% (15/213), and for isolated CABG 14% (16/112). In the AVR + CABG group, 100% (5/5) of patients with combined cross-clamp and fibrillation times greater than 120 minutes suffered MI. These results indicate that patients with combined AVR + CABG are subject to substantially greater risk of perioperative myocardial damage than the other groups. Excessive aortic cross-clamp times and fibrillation plus aortic cross-clamp times should be avoided in AVR + CABG patients.

Aortic Valve↗