Search PubMed⌕ Search

Biomedical subjects

B W Lytle

Publications and source records attributed to B W Lytle.

At least 109 records · Page 6Linked to original sources
PubMed1990

Reoperation for coronary atherosclerosis. Changing practice in 2509 consecutive patients.

We analyzed trends in clinical, angiographic, and operative variables and documented long-term survival in 2509 consecutive patients who underwent reoperation for myocardial revascularization at The Cleveland Clinic during a 20-year period (1967 to 1987). The patients were grouped into four cohorts by year of surgery. This analysis showed that vein graft atherosclerosis has become the leading indication for reoperation, and patient age and interval between operations continue to increase. Mortality rates ranged from 2% to 5% and, despite increasing comorbidity, more extensive coronary atherosclerosis, and worse left ventricular function, the hospital mortality rate was 2.9% from 1985 to 1987. Perioperative new Q-wave myocardial infarction occurred in 7% to 8% of patients from 1967 to 1984 but decreased to 4% in the 1985 to 1987 period (p = 0.04). Internal thoracic artery graft usage in reoperations increased from 27% in the 1967 to 1978 period to 67% in the 1985 to 1987 period. Advanced age and presence of left main coronary artery disease adversely influenced late survival more consistently than other factors. Patients operated on in 1967 to 1978 had fewer risk factors, which explains their higher survival rate compared with more recent cohorts. Factors associated with improved 10-year actuarial survival included age younger than 65 years, mild angina, no major comorbidity, no left main coronary artery disease, good left ventricular performance, and an internal thoracic artery graft.

Coronary Artery Disease↗
PubMed1990

Intraoperative Doppler color flow mapping for decision-making in valve repair for mitral regurgitation. Technique and results in 100 patients.

Mitral valve repair provides substantial advantages over mitral valve replacement in patients with severe mitral regurgitation. However, because of the possibility of persistent regurgitation, an intraoperative technique is needed to provide an immediate and accurate assessment of the adequacy of the repair before closure of the chest. One hundred patients with pure mitral regurgitation were studied with intraoperative epicardial Doppler color flow mapping immediately before and after valve repair. Intraoperative assessment of the severity of mitral regurgitation showed good agreement with preoperative left ventriculography and with standard precordial Doppler echocardiography before and after surgery. Postrepair intraoperative Doppler studies showed satisfactory surgical results in 92 patients. Postrepair intraoperative Doppler studies in the remaining eight patients demonstrated unsatisfactory results: persistent significant regurgitation in four, systolic anterior motion of the mitral valve with dynamic left ventricular outflow tract obstruction in three, and a persistent flail leaflet in one. In six of the eight patients, further surgery was performed during the same thoracotomy. In two patients, the intraoperative postrepair Doppler findings of persistent regurgitation were confirmed on precordial Doppler studies within 5 days, and mitral reoperation was required. Intraoperative epicardial Doppler color flow mapping provided a "safety net" that ensured a successful outcome in all 100 patients by providing the surgeon with a direct means to assess the success of the operation and the need for further surgery.

Echocardiography, Doppler↗
PubMed1990

Replacement of the ascending aorta. Early and late results.

From 1978 through 1987, 225 patients underwent operations that included replacement of the ascending aorta. One hundred twenty-three patients underwent composite aortic valve and ascending aortic replacement, 30 had aortic valve replacement with separate graft replacement of the ascending aorta, and 72 underwent replacement of the ascending aorta without aortic valve replacement. Thirty-one (13.8%) in-hospital deaths occurred. Univariate testing of preoperative and operative variables followed by logistic regression analyses identified miscellaneous aortic disease, coronary artery bypass grafting, aortic arch replacement, emergency operation, surgical date (1978 to 1983), and age (all p less than 0.05) as factors having independent association with in-hospital mortality. Follow-up of in-hospital survivors (mean interval 46 months, range 8 to 123 months) documented an overall 5-year survival rate of 76%, 83% after primary operation and 37% after reoperation. Univariate analyses followed by multivariate testing indicated that previous operation (p less than 0.0001) and a history of preoperative neurologic symptoms (p = 0.021) were associated with decreased late survival. At follow-up 88% of late survivors were free of symptoms. Seven patients have undergone reoperation 1 day to 69 months postoperatively. Although the in-hospital mortality for operations that include ascending aortic replacement exceeds that for isolated aortic valve replacement, the late death rate and rate of reoperation are low.

Adult↗
PubMed1989

Marfan's syndrome: natural history and long-term follow-up of cardiovascular involvement.

A retrospective analysis was undertaken to define the natural history and long-term follow-up of a group of patients with Marfan's syndrome. Eighty-four patients were diagnosed between January 1959 and June 1987 as having Marfan's syndrome; 68% were male; their ages ranged from 2 to 67 years (mean 26.6). Sixteen patients constituted the early surgical group (those who underwent surgery before 1979; mean age 36.1 years). Nineteen patients constituted the late surgical group (surgery in 1979 or later; mean age 33.3 years). The nonsurgical group comprised 49 patients (mean age 19.3 years). Fifty-seven percent of the patients had a diastolic murmur and 38% had cardiomegaly at presentation. Fifty-seven percent underwent cardiac catheterization, which revealed aortic root dilation (85%), aortic regurgitation (73%), aortic dissection (33%) and mitral regurgitation (36%). Thirteen of the 19 patients in the late surgical group received a composite graft repair of the ascending aorta as compared with only 2 of the 16 in the early surgical group. Follow-up information was obtained on 81 (96%) of 84 patients; the follow-up time was 2 to 332 months (mean 99). Thirty-one of the 81 patients died at age 3 to 63 years (mean age 35 years); 87% of the known causes of death were related to the cardiovascular system. Sixty-one percent of deaths were the result of aortic dissection or rupture or sudden cardiac death. Of the 50 survivors, 98%, including all patients in the late surgical group, were in functional class I or II. Overall survival at 5, 10 and 15 years after operation was 78.4%, 57.1% and 49.5%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Primary isolated aortic valve replacement. Early and late results.

A total of 1689 consecutive patients underwent isolated aortic valve replacement at the Cleveland Clinic Foundation from 1972 through 1986. There were 57 (3.4%) in-hospital deaths. Multivariate analysis identified advanced age (p = 0.0014), preoperative blood urea nitrogen level greater than 25 mg/100 ml (p = 0.008), New York Heart Association function class (p = 0.015), and preoperative atrial fibrillation (p = 0.04) as independent variables associated with increased in-hospital mortality and the use of cardioplegia for myocardial protection (p = 0.006) as a factor decreasing mortality. Follow-up documented survival rates of 85% and 66% and event-free survival rates of 71% and 43% at 5 and 10 postoperative years, respectively. Advanced age, moderate or severe impairment of left ventricular function, coronary artery disease, and preoperative blood urea nitrogen level greater than 25 mg/100 ml were associated with decreased late survival and event-free survival (all p less than 0.05). Patients with bioprostheses had better survival (p = 0.003) and event-free survival (p = 0.0007) rates than patients with mechanical valves. Patients with bioprostheses had superior results only if not receiving warfarin, and they experienced more reoperations and endocarditis; those with mechanical prostheses had more strokes, myocardial infarctions, bleeding complications, and thromboembolic events. Analysis of patients grouped according to age at operation showed that bioprostheses were associated with improved survival and event-free survival for patients 40 years older or older. Younger patients experienced more reoperations and episodes of endocarditis, and older patients more thromboembolic complications. We conclude that 10-year results after isolated aortic valve replacement are influenced by both patient-related and management-related variables, and the impact of these factors is different for patients of different ages.

Adult↗
PubMed1989

Ventricular aneurysm resection. Trends in surgical risk.

From 1972 to 1987, 1,183 patients underwent ventricular aneurysm resection. At 4-year intervals, this series was divided into four subsets that differed in patient and management-related variables. Comparison of patients seen from 1972 to 1975 with those seen in 1984-1987 shows a significant increase in mean age to 59.4 years, with 31.6% older than 65 years, an increase to 43.4% of patients with congestive heart failure, and a decrease to 42.8% of patients with angina. In the most recent interval, 30.7% of patients had mammary grafts, 81.1% had associated grafts, and 47.2% of patients were completely revascularized. Mortality rate, however, increased to 8%. Deaths were attributed to cardiac causes in 59.7% of cases. Multivariate analysis identified emergent procedures, advancing age, left main trunk disease, and history of congestive heart failure as risk factors. We conclude that the incidence of aneurysm resection is decreasing and operative risk has been constant despite advancing patient age and more extensive operative procedure.

Aged↗
PubMed1989

New arteries for old.

The internal thoracic artery has emerged as the coronary bypass graft of choice. Initially it was favored because of proximity to the anterior descending artery, little discrepancy in size between graft and recipient vessels, and high early patency rate. Later investigation showed relative freedom from arterial degeneration. In contrast to the 40-60% patency rate for vein grafts at 10-12 years postoperatively, the arterial graft patency exceeds 90%. Theories about protection from atherosclerosis are now directed toward vasoactive properties of the arterial wall. Exercise scintigraphic studies indicate that flow from a thoracic artery graft to the anterior descending artery relieves ischemia at peak myocardial demand. As expected, an arterial conduit that provides consistently high long-term patency also significantly improves 10-year survival in patients with one-, two-, or three-vessel disease. This extended longevity applies to patients with normal and abnormal left ventricular function. Late myocardial infarction, reoperation, and hospitalization for cardiac causes are significantly reduced by performance of an internal thoracic artery graft to the anterior descending coronary artery. These results have stimulated greater usage of these arterial grafts as bilateral, free, and sequential anastomoses. Preliminary reports indicate that patency related to expanded use is similar to that obtained with an in situ left thoracic artery graft. Indications and relative contraindications to arterial grafting in context of these current findings are discussed in this overview.

Coronary Artery Bypass↗
PubMed1989

Coronary artery bypass grafting with the right gastroepiploic artery.

The excellent results of coronary artery bypass with the internal mammary artery and the increasing numbers of patients who need coronary reoperations, but for whom conventional bypass conduits are not available, have prompted us to evaluate alternative arterial bypass conduits. The right gastroepiploic artery has been used as a coronary bypass graft in 36 patients (32 men), whose ages ranged from 29 to 71 years. Twenty-two patients had had previous coronary bypass grafting and six of these were undergoing their third bypass operation. The right gastroepiploic artery was used as an in situ graft to the right coronary artery or circumflex branches for 17 patients and as an aorta-coronary ("free") graft in 19 patients, six to the left anterior descending or diagonal, six to the circumflex, and seven to the right coronary artery. In conjunction with right gastroepiploic artery grafting, 16 patients received bilateral internal mammary artery grafts and 17 received one internal mammary artery graft. Histologically, right gastroepiploic artery segments from 18 patients could not be distinguished from internal mammary artery segments, and no evidence of atherosclerosis was found. Two patients died in the hospital, one intraoperatively and one 3 months after the operation, of a perioperative stroke. Perioperative morbidity included wound complication in three and reexploration for bleeding in two. At late follow-up 1 to 38 months after operation, two late deaths had occurred and 21 patients were free of symptoms. Postoperative angiography (postoperative interval 1 week to 13 months) was performed in nine grafts, three in situ grafts to the right coronary artery and six free grafts that included two to the left anterior descending, three to the circumflex, and one to the right coronary artery. All right gastroepiploic artery grafts were patient. The right gastroepiploic artery is an arterial conduit that can be used as an in situ graft to posterior coronary vessels and as a free graft to any coronary arterial system. Early graft patency has been excellent, and the histologic similarity between the right gastroepiploic artery and the internal mammary artery suggest that the long-term results will be favorable.

Adult↗
PubMed1988

Applicability of mitral valvuloplasty techniques in a North American population.

Records of 520 patients who underwent mitral valve operations were reviewed to determine the pathophysiology, etiology, anatomy of the valve lesion and use of valvuloplasty techniques. Pure mitral regurgitation, present in 269 patients (52%), was the most common lesion while rheumatic valvulitis, seen in 286 patients (55%), was the most common etiology. Degenerative lesions were found in 168 patients, 33% of the total and 63% of the pure mitral regurgitation group. Two-hundred seventy patients (52%) were treated with valvuloplasty techniques. The incidence of reconstructive procedures was determined for each of the various patient subsets. Overall hospital mortality was 5.6% in the series: 8.4% for mitral replacement compared with 3% for mitral valvuloplasty (p = 0.007). Among patients undergoing primary isolated mitral procedures, hospital mortality for replacement was 7.5% compared with 1.4% for valvuloplasty (p = 0.018). Mitral valvuloplasty seems to provide a therapeutic alternative applicable to the spectrum of mitral valve pathology seen in a North American population.

Female↗
PubMed1988

Coronary reoperations.

As coronary bypass surgery evolved from a procedure offered to good-risk patients into an intervention that is now applied to a spectrum of patients with many high-risk characteristics, so, too, reoperation for coronary surgery is now applied to an aging population with complicated atherosclerosis and abnormal left ventricular function. Despite our increased understanding of the factors that generate a need for reoperations and some potential avenues for preventing or delaying reoperations, the number of reoperations seems likely to increase. It is clear that the consistency of intraoperative myocardial protection must be improved; however, the favorable long-term results for these patients solidify the role of reoperation as an applicable intervention for patients with severe coronary atherosclerosis.

Aged↗
PubMed1988

Aortic valve replacement and coronary bypass grafting for patients with aortic stenosis and coronary artery disease: early and late results.

From 1967 to 1981, 294 patients (group A) with aortic stenosis and coronary atherosclerosis underwent aortic valve replacement (AVR) combined with bypass grafting; there were 13 (4.4%) in-hospital deaths. Follow-up of the in-hospital survivors documented late survival of 89%, 79%, and 52% at 2, 5, and 10 postoperative years, respectively. Univariate and multivariate testing identified age greater than or equal to 70 years (P = 0.02) and Class IV symptoms (P = 0.002) as factors decreasing late survival. Patients with bioprostheses who did not take warfarin had the best late survival (P = 0.03) and event-free survival (P = 0.05) and patients with mechanical prostheses who did not take warfarin had the worst (P less than 0.0001) (P = 0.001). From 1981 to 1986, 375 further patients (group B) with aortic stenosis and coronary artery disease underwent AVR and bypass grafting with 20 (5.3%) in-hospital deaths. Group B contained more patients greater than or equal to 70 years (35% vs. 16%) than did group A. Logistic regression analysis identified patients with moderate or severe impairment of left ventricular function and women as sub-groups with increased in-hospital mortality in group B. Patients with aortic stenosis and coronary artery disease can undergo AVR and bypass grafting with a risk slightly increased over that for isolated AVR. Bioprostheses enhance late survival and event-free survival.

Adult↗
PubMed1988

Intrathecal papaverine for the prevention of paraplegia after operation on the thoracic or thoracoabdominal aorta.

Eleven patients undergoing operation on the descending or thoracoabdominal aorta were administered papaverine intrathecally in an attempt to protect the spinal cord from ischemic damage. Concurrently, 19 patients, also undergoing operation on the thoracic or thoracoabdominal aorta, were operated on with a variety of conventional techniques, including distal aortic perfusion, but were not given intrathecal papaverine. No signs of early neurologic injury developed in any of the patients in the intrathecal papaverine group, although delayed paraparesis developed in one of the patients (9%; 70% confidence limits = 1% to 28%). On the other hand, eight of 19 patients undergoing operation with conventional techniques had either lower extremity paraparesis or paraplegia postoperatively (42%; 70% confidence limits = 29% to 57%; p = 0.058). Intrathecal papaverine appeared to provide spinal cord protection during thoracic aortic operations, particularly during prolonged periods of aortic cross-clamping. Papaverine was not associated with increased risk and may be superior to other conventionally used modalities. We conclude that continued evaluation of this technique is justified.

Adult↗
PubMed1988

Aortic valve replacement combined with myocardial revascularization. Late results and determinants of risk for 471 in-hospital survivors.

Among 500 patients consecutively undergoing primary aortic valve replacement combined with coronary bypass grafting from 1967 to 1981, there were 29 (5.8%) perioperative deaths. Follow-up of the late survivors ranged from 43 to 181 months (mean 85 months); actuarial survival rates were 88%, 77%, and 52% and event-free survival rates were 80%, 65%, and 32% at 2, 5, and 10 postoperative years. Cox proportional hazard analyses were used to identify determinants of late risk. Patient-related variables associated with decreased late survival rates included advanced age, cardiothoracic ratio 50% or greater, and preoperative New York Heart Association class III or IV symptoms. Moderate or severe impairment of left ventricular function as determined by angiography and advanced age were variables that decreased late event-free survival rates. Patients with bioprostheses had better survival rates (p less than 0.001) and event-free survival rates (p = 0.012) than did patients with mechanical valves. Analyses of subgroups according to the type of valve and postoperative anticoagulant management showed that both survival and event-free survival rates were decreased for patients with mechanical valves who were not taking warfarin and were enhanced for patients with bioprostheses who were not taking warfarin.

Aged↗
PubMed1988

Does bilateral internal mammary artery grafting increase surgical risk?

The risk of bilateral internal mammary artery grafting was studied in three groups of patients who were computer matched for recognized risk factors: year of operation, age, gender, extent of coronary artery disease, left ventricular function, completeness of myocardial revascularization, and history of congestive heart failure. The patient groups differed in the fact that they received veins only, one internal mammary artery graft, or two internal mammary artery grafts. The operative mortality rates for these three groups were 1.8%, 0.3%, and 0.9%, respectively (no significant difference). Analysis of perioperative morbidity demonstrated no significant differences except for a slight increase in transfusion requirements in the group receiving two internal mammary artery grafts (p = 0.04). None of the patients with only vein grafts had wound complications. One patient in the group with one internal mammary artery graft had a wound complication (0.03%). Eight patients receiving two internal mammary artery grafts had wound complications (2.4%) (p = 0.002). The prevalence of wound complications in patients with diabetes mellitus was 5.7% and in those without diabetes mellitus, 0.3% (p = 0.01). The prevalence of wound complications in patients less than 60 years of age was 0.2%, in patients in their 60s, 1.6%, and in patients older than 70, 3.1% (p = 0.01). Multivariate logistic regression analysis identified diabetes mellitus and age and not bilateral internal mammary artery grafting as risk factors for wound complications. We conclude that bilateral internal mammary artery grafting does not increase surgical mortality and increases surgical morbidity by a slight increase in the mean transfusion requirement.

Blood Transfusion↗
PubMed1987

Evaluation of normal prosthetic valve function by Doppler echocardiography.

Previous investigations have suggested that Doppler echocardiography is useful in detecting dysfunction in aortic (AVR) and mitral prostheses (MVR). However, to diagnose abnormalities, the spectrum of normal velocities through these valves must be established. Therefore, we used Doppler echocardiography to study 100 patients with 105 prosthetic valves that had no clinical evidence of valve dysfunction 9 +/- 8 days postoperatively. There were 66 Carpentier-Edwards (C-E), 23 St. Jude (S-J), and 16 Ionescu-Shiley (I-S) valves. In 70 AVR, the peak instantaneous gradient was 26.4 +/- 8.2 Hg, mean systolic gradient was 15.6 +/- 5 mm Hg, and gradients varied inversely with valve size, although differences were significant only when comparing the smallest vs the largest valve sizes (p less than or equal to 0.03). Peak instantaneous gradients greater than 36 mm Hg occurred only in AVR size 23 or smaller. There were no significant differences in gradients among C-E, S-J, and I-S AVR. In 35 MVR, mean gradient was 6.9 +/- 2.3 mm Hg and valve area was 2.7 +/- 0.8 cm2; neither varied significantly with valve size. However, S-J MVR group had smaller mean gradients and larger effective valve area than C-E bioprosthetic MVR (p = 0.01 and p = 0.05, respectively). Regurgitation was more common in AVR (26%) than in MVR (9%), p = 0.04, although all instances were mild and clinically silent. We conclude that normal AVR and MVR of a given size and type have a predictable range of Doppler echocardiographic parameters. Doppler evidence of mild regurgitation is a frequent finding in normal AVR and MVR.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗