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Biomedical subjects

T D Ivey

Publications and source records attributed to T D Ivey.

68 records · Page 4Linked to original sources
PubMed1982

Dacron patch closure of aortic annulus mycotic aneurysms.

Six patients with large mycotic aortic annular aneurysms were successfully operated on over a 3-year period. Aortic valve replacement was facilitated in all six patients by closing the orifice of the abscess with a Dacron patch and then seating the prosthetic valve at the level of the aortic annulus. In each case, a portion of the prosthetic valve ring was sutured directly to the patch. No patient has clinical evidence of a perivalvular leak 18-48 months after operation. One patient required reoperation to close a ventricular septal defect caused by partial patch dehiscence. Dacron patch closure has been highly effective in our experience and is simpler than many other options.

Adult↗
PubMed1981

Boerhaave syndrome. Successful conservative management in three patients with late presentation.

Three patients with Boerhaave syndrome were successfully managed with nonoperative treatment. The diagnosis was delayed 5 days in one patient and 10 days in the other two. None of the patients appeared septic. Their conditions had been misdiagnosed as myocardial infarction, pneumonia and pulmonary embolism. Treatment consisted of intravenous hyperalimentation and administration of antacids and antibiotics. Cimetidine was also used in one patient. Two patients were discharged 14 days after diagnosis and the third on the 20th hospital day. Follow-up barium swallows showed complete healing in 2 months in all three patients. Conservative management of spontaneous esophageal perforation is feasible when (1) the perforation is already 5 days old, (2) there are no signs of severe sepsis, (3) esophageal barium study shows a wide-mouthed cavity draining freely back into the esophagus, and (4) the pleural space is not contaminated. When the diagnosis is made promptly, surgical therapy remains the treatment of choice, and patients managed conservatively who show signs of sepsis should be operated on without hesitation. Follow-up esophageal evaluation should be performed to confirm complete healing and to evaluate underlying disease.

Antacids↗
PubMed1981

Echocardiographic appearance of the Chiari network: differentiation from right-heart pathology.

As echocardiography is being used more often, its value and accuracy are becoming more fully appreciated. Coincident with wider application of this imaging technique is the potential for identifying normal anatomic variants and their possible erroneous interpretation as pathologic states. In this report we describe the M-mode and two-dimensional echocardiographic features of a congenital remnant known as the Chiari network. This structure can present as a highly mobile, highly reflectant echo target that can be seen in several locations in the right atrium. We report here an index case that could be well examined echocardiographically and that was a cause of considerable concern due to the presence of congestive heart failure and a history of staphylococcal endocarditis. The presence of the Chiari network was confirmed pathologically. Subsequently, we found similar echocardiographic findings in 19 of 1248 patients (1.5%) studied in our laboratory. This congenital remnant, which is found pathologically in 2-3% of normal hearts, could be confused with valve disruption, vegetation or other mass lesion, particularly when associated with a suggestive clinical situation.

Adult↗
PubMed1981

Risks of coronary arteriography and bypass surgery in patients with left main coronary artery stenosis.

The risk of coronary arteriography is considerably increased in patients who have left main coronary artery stenosis (LMCAS). Among 1,060 patients undergoing coronary arteriography over a three-year period, 83 were found to have LMCAS and three of these patients died (3.6 percent) during or shortly after the arteriographic procedure. Bypass surgery, however, can now be carried out at a very low risk irrespective of the degree of coronary disease present--there was no hospital mortality in 74 patients with LMCAS undergoing bypass surgery at our institution during this period. In addition to careful attention to detail, techniques that can minimize the risk of both of these procedures in patients with LMCAS include invasive hemodynamic monitoring and various pharmacologic manipulations to prevent myocardial ischemia. In a small percentage of patients, rest angina may prove refractory to inhospital medical treatment, and intraaortic balloon pumping may be necessary to stabilize the conditions of these patients before proceeding with arteriography and myocardial revascularization.

Adult↗
PubMed1981

The practice of coronary artery bypass surgery in 1980.

We obtained information from 677 cardiac surgeons in the United States on the type of practice, case load, and techniques currently used for coronary bypass operations. These surgeons collectively performed 93,000 bypass operations in 1979. Less than 25% of these procedures were done in university or federal hospitals; the majority were performed in the private sector by surgeons engaged in a single specialty group practice. The mean case load in 1979 was 137 operations per surgeon, and only 46 (6.8%) did fewer than 25 bypass operations during that year. These surgeons devote a relatively small percentage of their professional activity to other areas in thoracic surgery--the majority do not perform congenital heart surgery and two thirds devote less than 10% of their professional activity to general thoracic surgery. Compared with our previous national survey done in 1975, techniques used for bypass grafting have changed considerably over the past 5 years. An increasing number of surgeons conduct cardiopulmonary bypass with an arterial input line introduced into the ascending aorta and with a single cannula for venous drainage and do not routinely vent the left ventricle. Cold chemical cardioplegia has become the technique of choice (by 91% of surgeons) for myocardial protection, sequential bypass grafts are now widely employed, and 83.2% of surgeons perform all distal anastomoses during a single period of cardioplegic arrest.

Cardiac Surgical Procedures↗
PubMed1981

Carotid arterial disease in patients undergoing coronary artery bypass operations.

The occurrence of stroke associated with coronary artery bypass operations is approximately 2%. In an attempt to reduce this incidence some centers have proposed carotid thromboendarterectomy for symptomatic and asymptomatic carotid arterial disease in patients undergoing a coronary artery bypass operation. To obtain a better understanding of the incidence of carotid occlusive disease in candidates for the coronary bypass operation and to evaluate the practical use of a noninvasive method to screen patients preoperatively, we evaluated 102 patients preoperatively with an ultrasonic Duplex scanner; 24 studies were requested on the basis of either previous neurologic problems or the presence of a bruit and 78 patients were evaluated as part of a study protocol. In the unrequested group 6% (5/78) of the patients had a stenosis of 50% diameter reduction or more. In the requested group 54% (13/24) had a stenosis of 50% diameter reduction or more. In the postoperative phase one stroke and one transient ischemic attack were noted among the unrequested group and none in those suspected of having carotid disease on clinical grounds. Neither affected patient had a high-grade stenosis. There is little evidence to support the contention that noninvasive screening of patients free of symptoms or signs of carotid disease prior to coronary artery bypass operation is a valuable method of screening for patients who will sustain a focal neurologic event.

Carotid Artery Diseases↗
PubMed1980

Selection of patients for coronary artery bypass operations.

Bypass operations have proved to be an effective treatment for advanced coronary artery disease. Randomized clinical trials have now shown that compared with medical treatment, bypass operations enhance survival in patients who have three-vessel disease or left main coronary stenosis. The goals of both medical and surgical treatment should be to improve a patient's quality of life, extend survival and reduce medical care costs. Preliminary data suggest that bypass operations may be less costly than medical treatment in patients with severe angina that requires repeated or prolonged stays in hospital.

Coronary Artery Bypass↗
PubMed1980

Membrane versus bubble oxygenator for cardiac operations. A prospective randomized study.

The advantages of membrane oxygenators over bubble oxygenators for cardiopulmonary bypass during clinical cardiac operations are controversial. A prospective randomized double-blind experimental design was utilized in 64 adult patients undergoing elective cardiac operations with either the Travenol microporous polyprolyene membrane oxygenator or the Bentley Q-100 bubble oxygenator. Sixteen patients in each group underwent coronary artery bypass grafting (CABG) and 16 underwent valvular or other types of operation. The two oxygenator groups were comparable in terms of patient characteristics and perioperative management. Both oxygenators functioned acceptably for an average duration of 115 minutes. Higher relative platelet counts (percent of control) were observed immediately after bypass in CABG patients in whom the membrane oxygenator was used. Otherwise, no significant differences were noted in objectively assessed results between the two oxygenators in regards to bleeding, pulmonary, renal, cardiac, and neurologic function, duration of ICU stay, and postoperative hospital stay. Thus no significant advantages in terms of clinical results could be detected with this type of membrane oxygenator versus another type of bubble oxygenator for elective cardiac operations in adults.

Adult↗
PubMed1979

Does preservation of the posterior chordae tendineae enhance survival during mitral valve replacement?

During a 30-month period, 51 patients underwent mitral valve replacement. There were 3 hospital deaths (5.9%), 2 of which were due to ventricular rupture. The 3 patients who died were among 13 patients in whom mitral valve replacement was combined with tricuspid or aortic valve operation or both. Postmortem findings in the 2 patients who died of ventricular rupture showed that the ventricular tears were located between the atrioventricular groove and the unresected papillary muscle stumps, in an area of ventricle formerly tethered by the posterior chordae tendineae. In the last 14 patients in the series, the posterior leaflet of the mitral valve and its chordae tendineae were left intact, and there was no mortality or prosthetic valve dysfunction. In patients with myxomatous or ischemic disease, the posterior leaflet was left completely intact. For patients with fibrocalcific rheumatic disease, we have developed a technique of partial excision and debridement of the posterior leaflet, preserving the intermediate and basal chordae tendineae attachments. With the techniques described, preservation of all or part of the posterior leaflet and its chordae tendineae does not appear to interfere with prosthetic valve function and, by reducing the risk of ventricular rupture, should enhance survival after mitral valve replacement.

Adult↗
PubMedDate not supplied

Effect of verapamil on regional myocardial contraction during graded ischemia in the dog.

Verapamil benefits patients with angina pectoris during exercise. The mechanism underlying this effect is controversial. A direct oxygen-sparing effect on ischemic myocardium has been proposed, but previous studies seeking to demonstrate this effect have been inconclusive because of inadequate control of systemic hemodynamics. This study has assessed the direct effects of verapamil on regional myocardial contraction during graded coronary flow reductions while blood pressure and heart rate were held constant. Verapamil caused a decrease in regional contraction at normal levels of coronary flow, a finding consistent with a negative inotropic effect. At lower coronary flows, however, ischemic dysfunction was similar in the presence and absence of verapamil. These findings fail to support the concept that verapamil either selectively depresses ischemic myocardium or enhances myocardial function during ischemia. Thus, these direct mechanisms would seem unlikely causes of the observed beneficial effect during exercise in patients with coronary artery disease.

Angina Pectoris↗
PubMedDate not supplied

Diastolic mechanical properties of the left ventricle after global ischemia.

The purpose of this study was to evaluate left ventricular (LV) diastolic mechanical properties after induced global ischemia using reliable new methods. The diastolic function of nonoxygenated crystalloid solution (CC sO2) was compared with those of oxygenated crystalloid (CC cO2) and oxygenated fluorocarbon cardioplegic (FC cO2) solutions. Postischemic ventricular performance was studied in 3 equal (no. 7) groups of dogs subjected to 120 minutes of global ischemia induced at an average myocardial temperature of 18.5 +/- 1.4 degrees C. LV diastolic function (chamber and myocardial stiffness) and relaxation (the exponential fall in LV pressure) were evaluated by sonomicrometry and Millar micrometers before ischemia and at 45 and 60 minutes after ischemia. LV chamber and myocardial stiffness in the CC sO2 group was significantly (p less than 0.05) elevated after ischemia, while the CC cO2 and FC cO2 groups did not show increases in LV chamber and myocardial stiffness after ischemia. LV relaxation before and after ischemia was not changed in any group. The myocardial water content of the CC sO2 group was significantly higher than that of the CC cO2 and FC cO2 groups (p less than 0.05). We conclude that (1) the postischemic increase in LV chamber stiffness in the CC sO2 group was dependent not only on the increase in intrinsic myocardial stiffness but also due to an increase in myocardial edema, and (2) there was no correlation between the LV relaxation rate and the leftward shift of diastolic compliance curves in the CC sO2 group.

Animals↗
PubMedDate not supplied

Mixed venous oxygen saturation and oxygen partial pressure as predictors of cardiac index after coronary artery bypass grafting.

OBJECTIVE: To determine the relationship between the mixed venous oxygen saturation (SvO2) and the cardiac index (CI) in individuals during the first 8 hours after coronary artery bypass grafting. DESIGN: Descriptive with a correlational design. SETTING: Cardiac intensive care unit at a university medical center in the midwestern United States. SUBJECTS: Twenty-one subjects (16 men and 5 women) undergoing coronary artery bypass grafting. OUTCOME MEASURES: SvO2, thermodilution cardiac output and CI measured every 2 hours during the first 8 hours after surgery. INTERVENTION: Elective coronary artery bypass grafting. RESULTS: Significant (p < 0.05) but moderate correlations between SvO2 and CI were found only at 6 and 8 hours after surgery (r = 0.66, p = 0.001; r = 0.44, p = 0.47). Secondary analysis determined that in subjects without lung disease, mixed venous oxygen tension (PvO2) had significant correlation with CI at all data collection times (r = 0.54 to 0.72; p = 0.003 to 0.02). CONCLUSIONS: The results of this study indicate that immediately after coronary artery bypass grafting, SvO2 cannot reliably predict CI. Although statistically significant results were found for the correlation between PvO2 and CI at all data collection times, the correlations were too low to support the use of the PvO2 as a reliable clinical predictor of CI without further study.

Adult↗