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Biomedical subjects

T B Ferguson

Publications and source records attributed to T B Ferguson.

At least 73 records · Page 4Linked to original sources
PubMed1989

Blood conservation in cardiac surgery. Preliminary results with an institutional commitment.

To evaluate the effect of blood conservation in cardiac surgery, use of blood products was analyzed in patients undergoing CABG before and after implementation of blood conservation techniques. Age, sex, coronary anatomy, ejection fraction, cardiopulmonary bypass time, and the preoperative hematocrit, platelet count, and clotting studies were similar in both groups. Methods of blood conservation included autologous transfusion of blood withdrawn before bypass, autotransfusion of shed mediastinal blood, strict protocols for transfusion, and acceptance of normovolemic anemia. With blood conservation, 25.5% of patients received no transfusions and 54.9% received blood only. Significant reductions (p less than 0.001) were achieved in the transfusion of blood from 6.8 +/- 2.4 to 2.3 +/- 2.6 units per patient and of plasma from 2.5 +/- 2.2 to 0.6 +/- 2.0 units per patient. Reductions in the use of platelets and cryoprecipitate were substantial, although not significant. Total donor exposure was reduced significantly from 13.1 +/- 7.3 to 4.3 +/- 6.7 donors per patient. The postoperative hematocrit was significantly lower and remained so at discharge. However, 30 days later there was no difference. This reduction in transfusion requirements decreased costs and donor exposure.

Aged↗
PubMed1988

Right ventricular free wall isolation: effects on regional myocardial blood flow.

The right ventricular isolation procedure was developed to treat medically refractory, nonischemic right ventricular tachycardia. The effect of this procedure on regional myocardial blood flow to the isolated right ventricle was evaluated in 10 adult mongrel dogs. There were no significant changes in aortic pressure, right ventricular systolic or diastolic pressure, or cardiac index following right ventricular isolation when the left ventricle and right ventricular free wall were synchronously paced. Myocardial blood flow to the isolated right ventricle was unchanged following the procedure (0.85 +/- 0.07 ml/min/gm to 0.87 +/- 0.08 ml/min/gm; p = not significant). Analysis of regional flow revealed that only a thin rim of right ventricular tissue near the ventriculotomy showed a significant decrease in blood flow (1.10 +/- 0.1 ml/min/gm to 0.29 +/- 0.04 ml/min/gm; p less than 0.05). Thus, this procedure leaves intact the blood supply to the great percentage of the right ventricular free wall. This finding supports the concept that the right ventricular isolation procedure is effective in isolating abnormal electrical activity without compromising regional myocardial blood flow.

Animals↗
PubMed1988

Hemodynamic consequences of right ventricular isolation: the contribution of the right ventricular free wall to cardiac performance.

Surgical isolation of the right ventricular free wall was performed in 10 dogs to evaluate both the hemodynamic effects of the procedure and the postoperative contribution of right ventricular free wall contraction to overall cardiac performance. Following the procedure, there was no significant differences in peak right ventricular systolic pressure, right atrial pressure, right ventricular stroke volume, or cardiac index. Cardiac index remained at preoperative levels over a wide range of filling pressures. However, there was a significant decrease in right ventricular stroke work (6.0 +/- 1.3 gm-m/m2 to 5.1 +/- 0.5 gm-m/m2; p less than 0.05). Pacing the isolated right ventricular free wall resulted in marked hemodynamic improvement compared with an electrically silent right ventricular free wall. Cardiac index increased from 1.7 +/- 0.2 L/min/m2 to 2.6 +/- 0.2 L/min/m2 (p less than 0.0005), and right ventricular stroke work went from 3.0 +/- 0.6 gm-m/m2 to 6.4 +/- 0.9 gm-m/m2 (p less than 0.0005). Right ventricular performance was also significantly related to the timing of right ventricular free wall contraction. Thus, the right ventricular free wall played an important role in the maintenance of normal cardiac hemodynamics.

Animals↗
PubMed1988

Coronary bypass grafting after failed elective and failed emergent percutaneous angioplasty. Relative risks of emergent surgical intervention.

Emergency coronary artery bypass grafting after failed elective percutaneous transluminal coronary angioplasty can be performed with acceptable complication rates. Recently, however, a new class of patients with unsuccessful angioplasty has evolved with the use of thrombolytic therapy and emergent angioplasty as treatment for developing acute myocardial infarction. The efficacy of surgical intervention after failure of angioplasty in this setting has not been demonstrated. This report compares the results of coronary bypass done emergently after either failed elective or failed emergent angioplasty. Between March 1984 and September 1986; 1350 angioplasty procedures were performed at our institution, 393 for acute myocardial infarction. Of the 111 patients who came to operation, 42 had had unsuccessful elective angioplasty and 69 unsuccessful angioplasty done in the clinical setting of an evolving acute myocardial infarction detected by electrocardiographic criteria. Twenty-one of the 42 patients having unsuccessful elective angioplasty (group I) and 32 of the 69 with unsuccessful emergent angioplasty (group II) underwent emergency coronary artery bypass grafting. A retrospective nonparametric statistical comparison of the two groups was performed. Age, preoperative ejection fraction, distribution of vessels undergoing angioplasty, and number of vessels bypassed were not statistically different. All group II patients received thrombolytic therapy, and a reperfusion catheter was used in over half the patients in each group. Three group I and six group II patients required a preoperative balloon pump, and half the patients in each group required postoperative inotropic support. One patient in group I (4.7%) and two patients in group II (6.2%) died (no significant difference). Only five patients in group I (23.8%) and 11 in group II (34.3%) had enzymatic and electrocardiographic evidence of an acute myocardial infarction at discharge. Six patients in group II (15.6%) required reexploration for bleeding, versus none in group I (p = 0.04). Nonhemorrhagic complication rates, mean in-patient and acute care days, total hospital charges, and blood product utilization rates were not statistically different. These data indicate that emergency coronary artery bypass grafting can be performed when necessary in the setting of failed emergent percutaneous transluminal coronary angioplasty with results comparable to coronary bypass after failed elective angioplasty.

Angioplasty, Balloon↗
PubMed1987

Electrical activity in the heart during hyperkalemic hypothermic cardioplegic arrest: site of origin and relationship to specialized conduction tissue.

Previous studies from this laboratory have shown that low-amplitude electrical activity (LEA) may occur during standard hyperkalemic hypothermic cardioplegic arrest and be undetected by routine monitoring techniques. The present study was designed to elucidate the electrophysiological nature of LEA. Ten dogs were monitored continuously during standard cardioplegic arrest using a 32-channel data acquisition system. In 7 animals (Part I), electrophysiological mapping of the lower right atrial septum during arrest was performed. The initial site of activation of LEA was consistently recorded from the region of the lower atrial septum prior to atrial or ventricular electrical activation. The site of origin of LEA was thus localized to the anatomical region of the atrial septum containing the atrioventricular nodal conduction tissue. In Part II, the electrophysiological mechanism of LEA was investigated in the remaining 3 animals utilizing an intrinsic property of specialized conduction tissue. Inclusion of a calcium channel-blocking agent in standard cardioplegic solution completely prevented the development of LEA in all 3 animals, which is in contrast to findings in previous studies using standard cardioplegic solution alone. These data suggest that LEA may be related to calcium-mediated activation of specialized conduction tissue. This mechanism of activation may explain why LEA cannot be detected by the intraoperative monitoring techniques routinely employed.

Animals↗
PubMed1987

Juvenile secretory carcinoma and juvenile papillomatosis: diagnosis and treatment.

Carcinoma of the breast in the child is a rare pathologic entity, constitutes less than 1% of all breast lesions in this age group. The case of a girl with a left breast mass first noticed at 4.5 years of age is presented. An eccentric subareolar mass was excised at 6 years of age, sparing her breast bud. This biopsy contained juvenile secretory carcinoma, with additional pathologic changes characteristic of juvenile papillomatosis. Both the juvenile papillomatosis component as well as the juvenile secretory carcinoma component were devoid of estrogen and progesterone receptors in contrast to nondiseased breast tissue. The assay for these receptors was performed using a new antireceptor monoclonal antibody technique. Simple mastectomy was performed after completion excision demonstrated tumor at the pectoralis major fascia.

Antibodies, Monoclonal↗
PubMed1987

Airway obstruction by vascular anomalies. Importance of telescopic bronchoscopy.

This review of 28 cases of airway obstruction by vascular anomalies in the past 6 years emphasizes the importance of these anomalies as causes of obstruction, stridor, and apnea in infants as well as the important contribution of telescopic bronchoscopy to the recognition of these lesions, especially compression of the trachea by the innominate artery. There were 20 patients with compression by the innominate artery; four were surgically corrected. Seven vascular ring anomalies were all corrected by operation as was an enlarged left atrium and malformed mitral valve in one patient. Vascular anomalies caused 26% of the obstructive airway lesions in a series of infants who had bronchoscopy for obstruction, stridor, or apnea. Failure to diagnose and treat these entities may result in progressive respiratory embarrassment and even death. Barium esophagogram and aortic arch arteriogram, the traditional modalities for diagnosing vascular rings, may fail to identify tracheal compression by enlarged cardiac chambers or the more common "anomalous" innominate artery. Telescopic bronchoscopy will identify tracheal compression by the innominate artery; furthermore, it will identify the area of compression by the vascular ring. Observation of the compressed area during corrective surgery ensures that the operative manipulations are appropriate and successful in relieving the obstruction. This observation can be facilitated by televised monitoring and videotaping.

Airway Obstruction↗
PubMed1986

Catheter reperfusion to allow optimal coronary bypass grafting following failed transluminal coronary angioplasty.

At present, intimal dissection, restenosis, or vessel closure occurs in approximately 5 to 10% of patients undergoing percutaneous transluminal coronary angioplasty. Coronary artery bypass grafting is usually required to remedy this complication and prevent substantial myocardial damage. The results of these revascularization procedures, however, are less satisfactory than those of elective coronary bypass grafting. Hemodynamic instability of the patients and the presence of ongoing myocardial ischemia usually necessitate that the operations be performed on an emergent basis. This report describes a series of 9 patients who had either dissected or re-stenosed coronary arteries at the time of angioplasty, as well as acute onset of ischemic symptoms. All underwent emergent coronary bypass grafting, but once it became apparent that angioplasty had failed, a specially designed reperfusion catheter was placed across the coronary lesion to reestablish blood flow to the ischemic area of myocardium. This catheter was removed after aortic cross-clamping and delivery of cardioplegic solution. The presence of the catheter thus reduced the ischemic period to the interval from the onset of dissection until the positioning of the catheter across the lesion. In all patients, the catheter temporarily reestablished coronary blood flow to the region of ischemic myocardium, thereby producing resolution of symptoms, and allowed antegrade delivery of cardioplegic solution infused into the aortic root to this area of myocardium. This, in turn, made it possible to perform the subsequent coronary bypass operation as a controlled, optimal revascularization procedure.

Angioplasty, Balloon↗
PubMed1986

Electrophysiologic effects of surgical isolation of the right ventricle.

Surgical isolation of the entire right ventricular free-wall was performed in ten dogs to evaluate the effects of the procedure on a variety of electrophysiologic measurements. Complete surgical isolation of the right ventricle was confirmed by determining that right ventricular electrical activity was not conducted to the remainder of the heart and that electrical activity in the atria or left ventricle did not conduct to the right ventricle. Right ventricular isolation caused no change in right ventricular or left ventricular pacing thresholds, in effective refractory periods of the right ventricle or left ventricle, or in right ventricular free-wall conduction time. Moreover, the normal conduction time from the right atrium to the left ventricle was 139 +/- 5 msec (mean +/- standard error) preoperatively and 135 +/- 5 msec postoperatively (p is not significant), showing that atrial-to-left ventricular synchrony was unaltered by isolation of the right ventricle. However, following isolation, the right ventricle could not be electrically fibrillated in 9 of 10 animals, a finding that may have important implications in the future development of surgical procedures to control chronic, life-threatening ventricular tachyarrhythmias.

Animals↗
PubMed1986

The electrophysiological effects of calcium channel blockade during standard hyperkalemic hypothermic cardioplegic arrest.

The addition of calcium channel-blocking agents to a standard hyperkalemic hypothermic cardioplegic solution has been examined both experimentally and clinically. None of these studies, however, have investigated the effect of calcium blockade during cardioplegic arrest on the specialized cardiac conduction tissues and on the subsequent development of arrhythmias after arrest. The present study examined the effect of adding nifedipine to standard cardioplegic solution administered in a canine experimental preparation modeled on routine clinical techniques. The time to and duration of electrical arrest following the administration of cardioplegia and the functional electrophysiological variables before and after arrest were measured using a 32-channel data acquisition system. The addition of nifedipine shortened the time to electrical arrest and prolonged the duration of arrest compared with standard potassium cardioplegic solution alone, without a deleterious effect on conduction function immediately after arrest. The occurrence of low-amplitude electrical activity (LEA) in both atria and ventricles during arrest was significantly reduced by the addition of nifedipine, thereby suggesting a possible correlation between LEA and calcium-mediated conduction occurring under conditions of standard cardioplegic arrest.

Animals↗
PubMed1986

Clinical and angiographic assessment of complex mammary artery bypass grafting.

The internal mammary artery has become the coronary bypass graft of choice in recent years because of enhanced long-term patency. Along with this trend, sequential, bilateral, and free mammary grafts have been employed more frequently in an effort to maximize the number of distal internal mammary anastomoses. This approach of maximally using the internal mammary artery (complex mammary grafting) seems logical, but at present little information about patency of the newer types of internal mammary artery grafts is available to justify the more complicated procedures. Over a 15 month period, 207 patients underwent bypass graft angiography from 1 to 32 weeks after operation. This is an 85% restudy rate for a consecutive series of coronary bypass procedures. Patency was defined as complete filling of the graft and distal vessel bypassed. A total of 841 distal vessels were grafted, or 4.1 per patient. The overall patency rate was 91% for 503 distal vein graft anastomoses and 99% for 338 internal mammary artery grafts. Individual patency rates of distal anastomoses, expressed as number patent/total (percent patent), were as follows: simple vein grafts, 262/285 (92%); sequential vein grafts, 196/218 (90%); left internal mammary artery to left anterior descending coronary artery, 109/110 (99%); left internal mammary to circumflex marginal artery, 14/14 (100%); right internal mammary to right coronary artery, 19/20 (95%); right internal mammary to left anterior descending coronary artery, 10/10 (100%); right internal mammary to circumflex marginal artery via transverse sinus, 18/20 (90%); sequential left internal mammary artery to left anterior descending system, 133/134 (99%); sequential left internal mammary to circumflex marginal system, 15/15 (100%); free internal mammary artery, 9/9 (100%); free sequential internal mammary artery, 6/6 (100%). Of the 18 patent transverse sinus right internal mammary grafts to the circumflex marginal artery, three exhibited very slow flow and probably were not functional. The hospital mortality associated with internal mammary revascularizations was 0.4% for nonemergency cases and 3.1% for emergency procedures. On the basis of clinical and postoperative graft patency data, expanded use of more complicated types of mammary grafts seems justified. Function of the right internal mammary graft to the circumflex marginal artery was suboptimal, and this method has been discontinued. All other complex mammary techniques had excellent patency rates as compared to vein grafts, and these differences may become even more significant in the late postoperative period.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1986

The effects of cardioplegic potassium concentration and myocardial temperature on electrical activity in the heart during elective cardioplegic arrest.

A major objective of cardioplegic arrest for protection of the heart during cardiac operations is total electromechanical quiescence. Recent studies from our laboratory in which we used multiple bipolar intracardiac and unipolar intramural electrodes have detected the presence of electrical activity in the lower atrial septum, the atrioventricular node-His bundle complex, and in ventricular myocardium during elective cardioplegic arrest that cannot be detected on the limb-lead electrocardiogram. Moreover, this low-amplitude electrical activity is not associated with visible mechanical activity of the heart and occurs at ventricular septal temperatures previously thought to be adequate for myocardial protection. The present study was designed to determine the effect of cardioplegic solution potassium concentration and myocardial temperature on the occurrence and duration of low-amplitude electrical activity during elective cardioplegic arrest. Fifty adult mongrel dogs were subjected to two consecutive 20 minute periods of cardioplegic arrest. The animals were divided into six groups, depending upon the cardioplegic solution potassium concentration they received and on whether or not topical cooling techniques were employed. The probability of occurrence of low-amplitude electrical activity during the arrest interval was significantly decreased by application of topical hypothermic techniques and reinfusion of hyperkalemic, as compared to normokalemic, cardioplegic solution. These effects of hyperkalemic cardioplegic solution and myocardial hypothermia acted synergistically, but independently, to decrease the likelihood of low-amplitude electrical activity occurring during the period of cardioplegic arrest. Nevertheless, low-amplitude electrical activity did occur in all groups after each cardioplegic solution administration and was not detected by routine monitoring techniques. This suggests that low-amplitude electrical activity may represent a fundamental type of metabolic activity that can be recorded from the heart during arrest and may be responsible for the temporary depression in ventricular function that frequently follows a period of elective cardioplegic arrest.

Animals↗