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Biomedical subjects

B W Lytle

Publications and source records attributed to B W Lytle.

At least 145 records · Page 8Linked to original sources
PubMed1985

Does mammary artery grafting increase surgical risk?

From 1980 through 1982, 7105 patients underwent primary isolated myocardial revascularization. Of these, 49.2% received only vein grafts and 50.2% received at least one internal mammary artery graft. The incidence of mammary artery grafting increased from 33.5% in 1980 to 67.1% in 1982. The operative mortality rate was 1.4% in the vein group and 0.2% in the mammary artery group (p less than .0001). A multivariate analysis identified six incremental risk factors for operative mortality. After adjusting for these risk factors, the use of vein grafts only was found to be an incremental risk factor (p less than .0001). In a subset of patients without major risk factors, there was no difference in the incidence of perioperative infarction, respiratory insufficiency, wound complication, stroke, use of intra-aortic balloon, reoperation for bleeding, or blood requirements. We conclude that internal mammary artery grafting is safe and is not associated with increased surgical morbidity or mortality.

Adult↗
PubMed1985

Myocardial revascularization: evolution of a surgical procedure.

Since its inception, myocardial revascularization has steadily evolved. The patient population is older with more extensive cardiac disease. Surgical mortality is currently 1% with a less than 1% perioperative myocardial infarction rate. The number of grafts done per patient has increased to more than three with 80% of the patients being completely revascularized. Ninety percent of the patients receive at least one internal mammary artery graft. With more complete revascularization and greater use of the internal mammary artery, the prospects for long-term survival and palliation have improved.

Adult↗
PubMed1985

In vivo hemodynamic comparison of porcine and pericardial valves.

The bovine pericardial valve and the SupraAnnular valve have been developed to improve the hemodynamic function of tissue valves. Hemodynamic performances of the standard Carpentier-Edwards porcine valve, the Carpentier-Edwards SupraAnnular valve, and the Carpentier-Edwards bovine pericardial valve were compared in the aortic position. One hundred patients undergoing aortic valve replacement were studied intraoperatively. Mean gradient across the valve decreased for standard and pericardial valves as valve size increased. At the same flow rate, the 23 mm pericardial valve had larger valve orifice areas, higher performance indices, and lower gradients than the 23 mm SupraAnnular valve. The SupraAnnular valve is hemodynamically superior to the standard Carpentier-Edwards porcine bioprosthesis. The Carpentier-Edwards pericardial valve, however, is less obstructive in the aortic position than either of the porcine valves.

Aortic Valve↗
PubMed1985

Hemodynamic performance of the Carpentier-Edwards pericardial valve in the aortic position in vivo.

The bovine pericardial valve was developed to improve the hemodynamic function of tissue valves. Eighty-one patients undergoing aortic valve replacement with the Carpentier-Edwards pericardial valve in the aortic position were studied intraoperatively. Mean gradient across the valve (mm Hg) decreased as valve size increased: size 19, 23.0 +/- 7.8; size 21, 19.7 +/- 6.6; size 23, 15.2 +/- 8.6; size 25, 13 +/- 4.0. Mean valve orifice area (cm2) increased as valve size increased: size 19, 1.1 +/- 0.4; size 21, 1.4 +/- 0.6; size 23, 2.0 +/- 0.7; size 25, 2.1 +/- 0.7. The mean transvalvular gradient, valve orifice area, and performance index increased as mean flow increased. The Carpentier-Edwards pericardial valve provides excellent hemodynamic performance that is acceptable even in size 19.

Animals↗
PubMed1984

Young adults with coronary atherosclerosis: 10 year results of surgical myocardial revascularization.

This study reviews data on 107 patients, aged 35 years or younger, who underwent surgical coronary revascularization from 1971 to 1975. Early clinical events included one operative death and five nonfatal perioperative myocardial infarctions. Late follow-up (mean interval after operation 115 months) demonstrated actuarial survival rates of 94% at 5 years and 85% at 10 years. Fifteen late deaths, 23 nonfatal myocardial infarctions, 13 reoperations and return of severe angina in 10 patients were considered late clinical events. Actuarial survival free of early or late clinical events was 77% at 5 years and 53% at 10 postoperative years. Testing of clinical, angiographic and operative variables for influence on survival and event-free survival showed that survival was decreased by multivessel disease and impaired left ventricular function; event-free survival was decreased by a family history of coronary disease and cigarette smoking. Both survival and event-free survival were decreased by diabetes and elevated serum cholesterol. Postoperative cardiac catheterization (64 patients, mean postoperative interval 47 months) demonstrated that mammary artery graft patency (25 of 27, 93%) exceeded vein graft patency (49 of 88, 56%, p less than 0.01). The atherogenic diatheses of young adults may compromise the operative result, whereas use of internal mammary artery grafts may enhance the palliation of bypass surgery.

Adult↗
PubMed1984

Primary myocardial revascularization. Trends in surgical mortality.

From 1970 to 1982, 24,672 patients underwent primary isolated myocardial revascularization: Group I, 4,517 patients operated upon from 1970 to 1973; Group II, 6,181 patients from 1974 to 1976; Group III, 6,869 patients from 1977 to 1979; and Group IV, 7,105 patients from 1980 to 1982. Operative mortality was 1.2% for the entire experience and 1.2%, 1.4%, 1.6%, and 0.8% for Groups I to IV, respectively. Mortality for Group IV was significantly lower (p less than 0.001). In decreasing order of significance, the risk factors were emergency operation, congestive heart failure, left main disease, female gender, history of congestive heart failure, advancing age, normothermic arrest, number of grafts, poor ventricular function, and incomplete revascularization. The same analysis of Groups I to IV demonstrated that advanced age, emergency operation, female gender, and congestive heart failure persisted as risk factors while incomplete revascularization and abnormal electrocardiogram emerged as new risk factors. Cardiac causes accounted for 203 (66.2%) patient deaths. This gradually decreased from 75.3% in Group II to 58.5% in Group IV. Neurological deficit was the second most frequent cause of death, 29 (9.6%), reaching a high in Group IV (18.9%). We conclude that (1) morbidity and mortality have decreased significantly despite increasing risk factors; (2) congestive heart failure has replaced emergency operation as the principal risk factor; (3) left main disease, number of grafts, and poor ventricular function have been neutralized as risk factors; and (4) cardiac causes of death are decreasing and being replaced by other system failure.

Age Factors↗
PubMed1983

Trends in selection and results of coronary artery reoperations.

The first 1,000 patients undergoing isolated coronary artery reoperation were divided into four cohorts of 250 patients each: 1969 to 1976; 1976 to 1979; 1979 to 1981; and 1981 into 1982. Graft failure as an indication for reoperation rose from 26% in Group 1 to 40% in Group 4, and the interval lengthened from 17 to 61 months, presumably a result of late closures 5 to 10 years postoperatively. Progressive atherosclerosis in previously ungrafted vessels has decreased from 62% in Group 1 to 23% in Group 4, a decline attributed to more complete revascularization initially. The frequency of three-vessel disease, stenosis of the left main coronary artery, and left ventricular impairment continues to rise in candidates for reoperation. Yet, operative mortality has declined from 5% to 2%, and most other forms of perioperative morbidity have decreased significantly when the early years are compared with the later experience. The number of grafts per patient has increased from 1.4 to 2.3, and complete revascularization in reoperations has increased from 65% to 76%. After a mean of 29 months, graft patency was 81% overall in 154 patients restudied after reoperation. Patency was similar for grafts to arteries previously involved with graft failure and to arteries not previously grafted. Five-year actuarial survival for patients in the first three cohorts (mean, 57 months) was 89%.(ABSTRACT TRUNCATED AT 250 WORDS)

Arteriosclerosis↗
PubMed1983

Multivessel coronary revascularization without saphenous vein: long-term results of bilateral internal mammary artery grafting.

When the saphenous vein is absent or inadequate, options for multivessel coronary revascularization include bilateral mammary artery grafting and the use of conduits of unproven durability (arm vein, homologous umbilical vein, prosthetic graft). To evaluate the long-term effectiveness of bilateral mammary artery grafting, we reviewed the cases of 76 consecutive patients with multivessel disease (33 with two-vessel disease, 43 with three-vessel disease) who underwent revascularization with bilateral mammary artery grafts only during the period from 1971 to 1980. No hospital deaths occurred. Thirty-three free and 119 in situ grafts were used. Late follow-up was complete, ranging from 12 to 132 months (mean interval, 67 months) and revealed improvement by at least one New York Heart Association functional class in 59 of 71 survivors. Postoperative arteriograms (mean interval, 26 months) of 55 grafts in 28 patients showed that 49 grafts were patent (89%). Five late deaths (2 noncardiac) occurred. Actuarial survival was 97.2% to seven years and 90.2% at nine years after operation. Bilateral mammary artery grafting yielded excellent graft patency, relief of symptoms, and long-term survival. When saphenous vein is unsuitable for grafting, bilateral mammary artery grafts should be utilized before other conduits are considered.

Actuarial Analysis↗
PubMed1983

Coronary artery surgery in women compared with men: analyses of risks and long-term results.

A surgical experience with 2,445 consecutive women who underwent isolated bypass grafting was analyzed for comparison with 18,079 consecutive men. Severe or unstable angina occurred preoperatively in 60% of women and 45% of men (p less than 0.001). Despite less three vessel disease (44 versus 56%, p less than 0.001) and better left ventricular contraction (normal in 60% of women and 53% of men [p less than 0.001]), women had a higher operative mortality rate (2.9 versus 1.3%). When matched for age, severity of angina and extent of coronary atherosclerosis, women still had twice the operative mortality of men. In matched patients, body surface area was the strongest predictor of operative risk, even when the model was adjusted for gender. When the model was adjusted for body surface area, gender was not an important predictor of operative death. The smaller size of women, rather than their sex, appears to explain the difference in operative mortality. After a mean interval of 2 years, women had a lower overall graft patency rate (76.4%) than men (82.1%) (p less than 0.001). At 5 and 10 years postoperatively, a higher percent of men were angina-free. Yet, survival for women (90.6%) and for men (93.0%) at 5 years, and at 10 years (78.6 and 78.2%, respectively) was not dissimilar.

Adolescent↗
PubMed1983

Replacement of aortic valve combined with myocardial revascularization: determinants of early and late risk for 500 patients, 1967-1981.

Five hundred consecutive patients underwent aortic valve replacement and coronary revascularization in the years from 1967 to 1981, with 29 (5.9%) in-hospital deaths. Current operative mortality (1978-1981) is 3.4%. Univariate and multivariate analyses were used to identify determinants of early and late risk. Female sex, aortic insufficiency, and advanced age increased in-hospital mortality, whereas use of cardioplegia decreased it. At follow-up of 471 patients who survived hospitalization for 1 to 135 months (mean 41) after surgery, 96 late deaths were documented. Survival rates were 87%, 80%, and 55%, and event-free survival rates were 80%, 65%, and 39% at 2, 5, and 10 years after surgery, respectively. The late survival rate was unfavorably influenced by the presence of moderately or severely impaired left ventricular function and double-vessel coronary disease; the rate was enhanced for patients in age group from 50 to 59 years old and was not influenced by the method of myocardial protection. The event-free survival rate decreased with the presence of moderately or severely impaired left ventricular function and was enhanced for patients with New York Heart Association class I or II symptoms before surgery. Patients with bioprostheses who did not receive anticoagulants had higher survival and event-free survival rates than did either patients with bioprostheses who received anticoagulants or patients with mechanical valves, whether they received anticoagulants or not.

Age Factors↗
PubMed1982

Early clinical evaluation after aortic valve replacement with the St. Jude Medical valve in patients with a small aortic root.

Forty-three patients, nine men and 34 women, mean age 60 years (range 23-81 years), who had small aortic roots underwent aortic valve replacement with a St. Jude Medical valve. Preoperatively, five patients were in New York Heart Association (NYHA) class I, 19 were in class II, 15 were in class III and four were in class IV. In 30 of 36 patients with aortic stenosis, the mean gradient was 102 mm Hg (range 52-175 mm Hg; in six patients with aortic stenosis, the gradient was not measured. Seven patients underwent surgery for aortic regurgitation. Ten patients received a 19-mm valve, 29 a 21-mm valve and nine a 23-mm valve. Two patients (4.6%) died in the hospital, one immediately postoperatively and the other from low cardiac output 9 days postoperatively. There are 670 patient-months of follow-up (mean 17 months). Thirty-six patients are NYHA class I and two patients are in class II. There have been no thromboembolic episodes in 605 months of follow-up for patients maintained on warfarin. There was one partial valve thrombosis among eight patients being managed without warfarin. No mechanical valve failures have occurred. The St. Jude Medical valve provides a satisfactory early result when used to replace the aortic valve of patients who have a small aortic root.

Adult↗
PubMed1981

Late clinical and arteriographic results in 500 coronary artery reoperations.

The incidence of coronary artery reoperations averaged 2.7% from 1967 through 1979. In a mean interval of 51 months between operations, three-vessel disease increased from 24% to 63%, and 31% of these 500 consecutive patients lost previously normal left ventricular function. Three angiographic indication groups were identified: (1) progressive coronary atherosclerosis, 247 (51%); (2) graft failure, 147 (29%); and (3) a combination of progressive coronary atherosclerosis and graft failure, 96 (19%). Angina recurred earlier in patient with graft failure, mean 17 months compared with a mean of 37 months for the other groups. Twenty (4%) operative deaths occurred. The series is divided into 387 patients operated upon under normothermic anoxic arrest and 113 with systemic hypothermia and cold cardioplegia. In the cardioplegia group, perioperative myocardial infarction was 2.7% in comparison with 7.8% for patients with anoxic arrest (p = 0.055). The number of grafts per patient increased from 1.0 to 1.9 and blood usage decreased from 11 units to 2.7 units. After a mean follow-up of 42 months, angina was relieved or improved in 86%. Recatheterization of 104 patients after a mean interval of 19 months showed a 79% vein graft patency rate and a 97% mammary artery graft patency rate. Grafting performed for graft failure (47) yielded an 85% patency rate. Actuarial 5 year survival was 87.4% for those with progressive atherosclerosis, 89.4% for patients with graft failure, and 91.5% for the combined indication group. Clinical improvement, graft patency, and long-term survival are nearly equal among the indication groups. Palliation derived from these reoperations approaches that achieved after primary revascularization.

Adult↗