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Biomedical subjects

W G Marshall

Publications and source records attributed to W G Marshall.

At least 19 recordsLinked to original sources
PubMed1990

Risks of bilateral internal mammary artery bypass grafting.

Although use of one internal mammary artery (IMA) for coronary artery bypass grafting does not appear to be associated with increased risk, the results with both IMAs are less certain; the potential for a higher incidence of sternal wound infection as a result of devascularization of the sternum is a major concern. During a 42-month interval ending July 1988, 1,566 patients had coronary artery bypass grafting alone or in combination with other procedures: 633 received only vein grafts, 687 had unilateral IMA grafting, and 246 had bilateral IMA grafting. The IMA patients were younger, were more often male, had better cardiac function, and underwent fewer emergent, urgent, or combined procedures than the patients receiving vein grafts (p less than 0.05). Thirty-day mortality was lower among the IMA patients (unilateral IMA group, 2.8%; bilateral IMA group, 3.7%; and vein graft group, 7.9%; p = 0.001). With the exception of sternal wound problems, occurrence rates for postoperative complications among the IMA patients did not differ significantly from or were lower (p less than 0.05) than those among the patients with vein grafts. Sternal infections occurred with greater frequency among the bilateral IMA patients (6.9%) than among the unilateral IMA (1.9%) or vein graft (1.3%) patients (p = 0.001). By univariate analysis, obesity, diabetes, bilateral IMA grafting, and need for prolonged (greater than 48 hours) mechanical ventilation were associated with a significantly higher incidence of sternal infection (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

Increased complications and prolonged hospital stay in elderly cardiac surgical patients with low serum albumin.

Cardiac surgery in elderly patients is associated with acceptable operative mortality but an increased complication rate. Malnutrition is common in the elderly and may adversely affect surgical outcome. To determine the effect of hypoalbuminemia on postoperative complications, 92 patients greater than or equal to 75 years (range 75 to 90) undergoing a variety of major cardiac surgical procedures were evaluated. Thirteen patients (14%) had a serum albumin level less than 3.5 g/dl preoperatively. Compared to patients with normal albumin, hypoalbuminemic patients had an increased frequency of postoperative confusion, congestive heart failure, low cardiac output, renal dysfunction and gastrointestinal complications (all p less than 0.05). Mean postoperative length of stay was markedly prolonged in these patients (27 vs 12 days; p less than 0.001), and mortality also tended to be higher (31 vs 13%; p = 0.11). Using multivariate analysis, albumin less than 3.5 g/dl was the most powerful predictor of postoperative renal dysfunction (p less than 0.01), and was also an independent predictor of increased length of stay (p less than 0.01) and gastrointestinal disorders (p less than 0.05). Thus, hypoalbuminemia is a powerful indicator of an increased risk of perioperative complications in elderly patients undergoing cardiac surgery. Increased attention to nutritional factors is warranted in these patients.

Aged↗
PubMed1989

Intraoperative ultrasonic imaging of the ascending aorta.

Embolization of atherosclerotic material from the ascending aorta resulting from placement of cannulas or vascular clamps is a major cause of stroke during cardiac surgical procedures. In an effort to identify atherosclerotic disease of the ascending aorta which might predispose to embolization, intraoperative B-mode ultrasonography was performed in 50 patients. The aorta was imaged from the aortic annulus to the origin of the innominate artery in transverse and longitudinal views. The results were compared with visual and tactile examination of the aorta for the presence of atherosclerosis. Ultrasonic imaging demonstrated atherosclerotic disease in 29 patients (58%). Visual examination and palpation identified atherosclerosis in 12 patients (24%). The amount and location of plaque was sufficient to require a change in the site of arterial cannulation or the proximal vein graft anastomoses or the technique of cardiopulmonary perfusion in 12 of the 50 patients (24%). All 12 patients were 65 years of age or older. Palpation underestimates the presence of atherosclerotic disease in the ascending aorta. Intraoperative ultrasonography accurately identifies patients with atherosclerotic disease of the ascending aorta. This allows the surgeon to modify cannulation, perfusion, and operative techniques to reduce the risk of perioperative stroke due to the embolization of atherosclerotic debris from the ascending aorta.

Aged↗
PubMed1989

Avoidance of embolic complications by ultrasonic characterization of the ascending aorta.

Surgical manipulation of the atherosclerotic ascending aorta in elderly patients is often accompanied by serious complications. To reduce the risk of disrupting highly degenerated but nonpalpable plaques, we used quantitative ultrasonic techniques to intraoperatively image the ascending aorta in 33 patients (mean age, 71 years) as a guide to selection of cross-clamping or cannulation sites. Two-dimensional, integrated backscatter images (integration time, 1.6 mu sec) were obtained with a 5-MHz transducer wrapped in a sterile sheath and placed directly on the aorta. Significant atherosclerotic disease was detected in 18 patients. Calcified lesions were found in 13 patients, and fibrofatty lesions were found in five. In four patients undergoing repair of degenerative aneurysms, the extent and distribution of ultrasonically delineated regions of calcification and fibrosis were confirmed histologically. In eight (24%) patients, the composition, severity, and location of plaques delineated ultrasonically led to selection of alternate cannulation sites without resultant atheroembolism. Thus, ultrasonic tissue characterization sensitively delineates the extent of aortic atherosclerosis, and its use may decrease the risk of atheroembolism.

Aged↗
PubMed1989

Coronary artery bypass grafting for postinfarction angina pectoris.

The variables that predict increased operative risk and postoperative morbidity among patients who undergo coronary artery bypass grafting (CABG) early after myocardial infarction for persistent or recurrent ischemia are incompletely defined. In a recent 3-year interval (1985-1987), 240 patients underwent CABG within 30 days of a documented myocardial infarction. Thirty-day mortality was 3.3% (eight patients). Twenty variables were examined by univariate and multivariate analysis for their effects on early mortality. Left main coronary artery disease (p = 0.0003), female sex (p = 0.0059), and preoperative left ventricular dysfunction (increased left ventricular wall motion score) (p = 0.0135) were significant independent predictors of increased 30-day mortality. Postoperative inotropic support for low cardiac output was required for 55.6% of patients operated upon within 24 hours of infarction as compared with 11.6% of patients operated upon between 1 and 30 days (p less than 0.01). Significantly more patients undergoing emergent CABG required postoperative intra-aortic balloon pumping and inotropic support than those patients who underwent urgent or elective operation (23.8% vs. 4.6% and 52.4% vs. 10%, respectively) (p less than 0.01). Other studies confirm that preoperative left ventricular dysfunction, presence of cardiogenic shock, or intra-aortic balloon pumping are important predictors of operative risk. Other variables that may be important include advanced age, female sex, left main coronary artery disease, and anterior transmural infarction. The timing and urgency of operation have not been shown to be significant and independent determinants of increased operative risk.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Vasorelaxant effects of atriopeptins in human internal mammary artery.

The vasorelaxant effects of the atriopeptins, AP-(103-126) and AP-(103-123) were compared in human internal mammary artery (IMA) rings which had been contracted with norepinephrine. AP-(103-126) completely relaxed the IMA with an IC50 within the physiologically relevant range (15 nM). However, relaxation with AP-(103-123) was greatly reduced compared to AP-(103-126), with complete relaxation observed in only half of the vessels tested and only at concentrations of 10-50 microM. These results indicate that the atriopeptin (AP) receptor in human arteries may be more similar to the AP receptor in rabbit rather than rat arteries.

Adult↗
PubMed1988

Coronary artery bypass grafting in patients with a tracheostoma: use of a bilateral thoracotomy incision.

The performance of cardiac surgical procedures via median sternotomy in patients with a tracheostoma can present difficult problems, including stomal necrosis, mediastinitis, and inadequate operative exposure. Bilateral thoracotomy is an alternative approach in such patients. This approach separates the stoma from the operative field and provides satisfactory exposure for internal mammary artery dissection and performance of coronary artery bypass grafting.

Aged↗
PubMed1988

Morbidity and mortality of coronary bypass surgery in patients 75 years of age or older.

To determine factors associated with an increased risk of postoperative complications in elderly patients, 60 consecutive patients 75 years of age or older undergoing isolated coronary artery bypass grafting (CABG) were evaluated. Thirty-nine patients (65.0%) had at least one major postoperative complication, including 2 deaths (3.3%). Low body weight was the only univariate predictor (p less than 0.05) of an increased likelihood of complications overall. Prior cardiac operation, low serum cholesterol value, and prolonged cardiopulmonary bypass time were associated with increased bleeding. Electrocardiographic evidence of left ventricular hypertrophy was associated with prolonged postoperative confusion. Age of 80 years or more and increased cross-clamp time were predictive of pulmonary dysfunction. Low cardiac output occurred more frequently in patients with nonsinus rhythm, prior cardiac operation, recent congestive heart failure, or elevated level of blood urea nitrogen. Identification of risk factors for specific complications should prompt further studies to define ways of reducing morbidity and the resultant high cost associated with CABG in elderly patients.

Aged↗
PubMed1988

The coronary-subclavian steal syndrome: report of a case and recommendations for prevention and management.

The coronary-subclavian steal syndrome involves the siphoning of blood from the myocardium through an internal mammary artery graft because of a proximal subclavian artery stenosis or occlusion, and results in myocardial ischemia. With the increased use of the internal mammary artery for myocardial revascularization, the potential exists for recurrence of angina pectoris in patients who have or in whom develops high-grade stenosis or occlusion of the subclavian artery, because of the coronary-subclavian steal syndrome. The coronary-subclavian steal syndrome can be prevented by the identification of patients with or at risk to develop subclavian artery occlusive disease. All patients undergoing cardiac catheterization prior to coronary artery bypass grafting in which use of the internal mammary artery is anticipated should be evaluated for the presence of upper extremity and cerebrovascular ischemia, the presence of cervical or supraclavicular bruits, and an upper extremity blood pressure differential of 20 mm Hg or greater. Patients with these findings or with evidence of diffuse atherosclerotic vascular disease should have brachiocephalic arteriography at the time of coronary arteriography to identify significant subclavian artery occlusive disease. When this is demonstrated, use of the internal mammary artery as a free graft instead of an in situ graft or use of saphenous vein grafts is indicated. Patients in whom recurrent angina develops following coronary artery bypass grafting that included an internal mammary artery graft should have coronary arteriography to evaluate the presence of coronary-subclavian steal syndrome, and brachiocephalic arteriography. Carotid-subclavian bypass grafting, probably best done with a prosthetic conduit, is the procedure of choice for management of the coronary-subclavian steal syndrome.

Angina Pectoris↗
PubMed1988

Management of recurrent superior vena caval syndrome with an externally supported femoral vein bypass graft.

Management of superior vena caval syndrome with an autogenous vein bypass graft can be complicated by occlusion of the bypass graft. The case of a patient with recurrent superior vena caval syndrome due to occlusion of a spiraled saphenous vein graft who was managed with a femoral vein graft supported externally by a sleeve of ringed polytetrafluoroethylene is presented. A venogram demonstrated patency of the graft 11 months postoperatively, and the patient remains free from clinically apparent superior vena caval obstruction 18 months postoperatively.

Adult↗
PubMed1988

Carotid endarterectomy based on duplex scanning without preoperative arteriography.

Between July 1985 and September 1987, 25 patients underwent 26 carotid endarterectomies based on an abnormal duplex scan (B-mode ultrasonography and pulsed-Doppler sound spectral analysis) indicative of severe stenosis or ulceration. Arteriography was not performed because of severe unstable angina requiring coronary artery bypass grafting (23 patients) or patient preference (two). Twelve patients were symptomatic, and 13 were asymptomatic but had severe (greater than or equal to 75%) bilateral or unilateral carotid artery stenosis. Operative and pathological analyses confirmed the duplex-scan findings in all 25 cases. All 25 patients survived the operation. One patient had a transient ipsilateral neurological deficit, and one had a permanent contralateral neurological deficit. Five patients died of ventricular arrhythmias within 30 days of operation. Duplex scanning is an accurate method for determining the presence of clinically and hemodynamically significant carotid arterial occlusive disease. Duplex scanning also serves as an alternative method for evaluating patients for whom carotid arteriography may be associated with significant risk.

Aged↗
PubMed1986

Management during reoperation of aortocoronary saphenous vein grafts with minimal atherosclerosis by angiography.

The proper management of saphenous vein grafts showing minimal angiographic evidence of atherosclerosis at the time of reoperation for progressive atherosclerosis in the native coronary circulation or for severe atherosclerosis in other saphenous vein grafts is uncertain. Following the occlusion of vein grafts in 2 patients 7 and 12 years after operation but only 2 years after arteriography demonstrated no major abnormalities in the grafts, we adopted a policy of elective replacement of all saphenous vein grafts, irrespective of angiographic findings, when reoperation was necessary 5 or more years after the initial operation. Between July, 1984, and May, 1985, 16 patients had repeat coronary artery bypass grafting 6 to 13 years (mean, 9 years) after the initial procedure. Complete revascularization was carried out in all patients. In each, it included replacement of at least 1 saphenous vein graft showing no severe obstruction (less than 30% of the luminal diameter) and no (5 patients), minimal (8), or moderate (3) luminal irregularities by angiography. By pathological examination, 3 of the grafts had minimal, 5 had moderate, and 8 had severe atherosclerotic changes present. These changes were generally more diffuse than those observed by angiography. Because angiography underestimates the severity of the atherosclerotic degeneration in saphenous vein grafts and because of the propensity of the atherosclerotic disease to progress at an unpredictable rate, we recommend routine replacement of all saphenous vein grafts at the time of reoperation if done 5 or more years after the initial procedure.

Adult↗
PubMed1986

Coronary artery bypass grafting in dialysis patients.

Cardiac disease continues to be a major cause of death in patients undergoing long-term hemodialysis. The results of coronary artery bypass grafting (CABG) for severe coronary artery disease in long-term hemodialysis patients have been studied in a group of 12 patients who underwent CABG between January 1979 and December 1983. Hospital mortality was 8% (1 of 12 patients). This patient died of ventricular arrhythmia. Two late deaths occurred, 1 from peritonitis in a patient undergoing long-term peritoneal hemodialysis and 1 from metastatic renal cell carcinoma. The two postoperative complications (morbidity 17%) consisted of a sternal dehiscence secondary to mediastinitis and a perioperative cerebrovascular accident. Ten of the 11 hospital survivors experienced complete relief from angina. In the other patient the angina became easier to control with medication. Combining this series of patients with those previously reported in the literature allows determination of actuarial survival in a group of 25 patients followed up for 1 to 79 months (mean, 33 months). Actuarial survival was 83% at one year, 69% at three years, and 48% at five years. This is not significantly different from the survival of long-term hemodialysis patients who have coronary disease but have not undergone CABG. It appears that CABG, when performed in long-term hemodialysis patients, is associated with an only slightly greater risk of mortality and morbidity than CABG performed in routine patients. Although CABG provides considerable symptomatic relief of angina, no statistically significant change in actuarial survival can be demonstrated.

Aged↗
PubMed1986

Eleven-year experience with composite graft replacement of the ascending aorta and aortic valve.

Between September, 1974, and December, 1985, 127 patients had replacement of the ascending aorta and aortic valve with a composite graft. Annuloaortic ectasia was the most common indication for operation (69 patients), followed by aortic dissection (51 patients). Twenty-four patients (19%) had the Marfan syndrome. Hospital mortality was 4.7%. Emergent operation for acute dissection was the only independent predictor of hospital death (p = 0.03). Reoperation for postoperative hemorrhage was required in 15 patients (11.8%) and for prosthesis-related complications (pseudoaneurysm, prosthetic endocarditis, technical problems, and valve thrombosis) in 16 patients (12.6%). Since we adopted a technique of preclotting the prosthesis with whole blood or albumin plus autoclaving and abandoned the inclusion technique, the reoperation rate has declined substantially. At 5 years, the actuarial freedom from reoperation for any reason on the ascending aorta or aortic valve for the 24 patients in whom this modification was used was 90% and for the remaining 103 patients, 73% (p = 0.17). No reoperations for pseudoaneurysms or technical problems were required in these 24 patients, whereas 10 reoperations for these complications were necessary in the other patients. The mean duration of follow-up was 54 months. The actuarial survival rate at 7 years for the entire group was 65%; for the patients with annuloaortic ectasia, 70%; for those with aortic dissection, 61%; for the patients with the Marfan syndrome, 57%. Actuarial freedom from operation on the remainder of the aorta at 7 years was 89%, but it was 78% for the subgroup with the Marfan syndrome. The satisfactory results with extended follow-up support the continued use of the composite graft technique as the preferred method of treatment for patients with annuloaortic ectasia or recurrent aneurysms of the sinuses of Valsalva and for patients with aortic dissection who require aortic valve replacement.

Actuarial Analysis↗
PubMed1984

Early results of valve replacement with the Björk-Shiley convexoconcave prosthesis.

The Björk-Shiley convexoconcave prosthetic valve has design characteristics that may result in a lower incidence of thromboembolic complications than the conventional spherical Björk-Shiley prosthesis. We evaluated the results of valve replacement with the convexoconcave prosthesis in 248 patients receiving 301 prosthetic valves between March, 1979, and June, 1981. One hundred thirteen patients had aortic valve replacement (AVR), 73 had mitral valve replacement (MVR), and 62 had multiple valve replacement. Two hundred nine (84%) were in New York Heart Association Class III or IV. The median duration of follow-up was 13 months, and follow-up information was available for 246 (99%) of the patients. The actuarial incidence of freedom from thromboembolism at two years was 98% in the AVR group, 97% in the MVR group, and 87% in the group having multiple valve replacement. There were no documented episodes of valve thrombosis or mechanical failure and no fatal thromboembolic complications. The absence of valve thrombosis is in marked contrast to the results reported with the spherical disc valve. Although longer follow-up is necessary, it appears that the convexoconcave design represents a major improvement in the Björk-Shiley prosthesis.

Adolescent↗