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Biomedical subjects

T M Bateman

Publications and source records attributed to T M Bateman.

At least 55 records · Page 3Linked to original sources
PubMed1984

Detection of occult pericardial hemorrhage early after open-heart surgery using technetium-99m red blood cell radionuclide ventriculography.

Pericardial or mediastinal hemorrhage requiring reoperation occurs in 2% to 5% of patients, usually early (0 to 48 hours), after open-heart surgery. This hemorrhage may be occult, and resulting cardiac tamponade may easily be misinterpreted as ventricular dysfunction, common early postoperatively. In such cases, appropriate and timely intervention may not occur. Of 50 patients evaluated by technetium-99m red blood cell gated equilibrium radionuclide ventriculography (RNV) because of early postoperative cardiogenic shock of uncertain etiology, 17 had unique scintigraphic images suggestive of intrathoracic hemorrhage. Of these 17, 5 had a generalized "halo" of abnormal radioactivity surrounding small hyperdynamic right and left ventricles, 11 had localized regions of intense blood pool activity outside the cardiac chambers (two with compression of single chambers), and one demonstrated marked radionuclide activity in the right hemithorax (2000 ml of blood at reoperation). Twelve patients had exploratory reoperation for control of hemorrhage as a direct result of the scintigraphic findings, three were successfully treated with fresh frozen plasma and platelet infusions along with medical interventions to optimize cardiac performance, and two patients died in cardiogenic shock (presumed tamponade) without reoperation. In the 12 reoperated patients, all were confirmed to have active pericardial bleeding. Scintigraphic localization of abnormal blood pools within the pericardium corresponded to the sites at which active bleeding was witnessed at reoperation. The abnormal bleeding was etiologically related to the tamponade state, with marked improvement in hemodynamics after reoperation. Nine additional patients were reoperated for presumed tamponade after RNV revealed an exaggerated halo of photon deficiency surrounding the cardiac chambers.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiac Surgical Procedures↗
PubMed1984

Myocardial infarction during coronary artery bypass surgery--benign event or prognostic omen?

Our observations and experience suggest that an adverse outcome from perioperative infarction occurs predominantly in a defined population of patients. A worsened prognosis and special postoperative interventions need not be anticipated in patients who have simply developed new Q waves after bypass surgery and are free of malignant ventricular arrhythmias and severe degrees of myocardial dysfunction. Furthermore, our data indicates that repeat throacotomy because of bleeding or tamponade early after sustaining a perioperative infarction will adversely affect the outcome of that infarction.

Aged↗
PubMed1984

Diffuse slow washout of myocardial thallium-201: a new scintigraphic indicator of extensive coronary artery disease.

When coronary artery disease is extensive and of relatively uniform severity, regional myocardial hypoperfusion may be balanced during stress, precluding development of spatially relative perfusion defects. Assessment of the washout of thallium-201 from myocardial regions may provide diagnostic assistance in these cases because washout analysis is spatially nonrelative and hypoperfused myocardial regions manifest a slow thallium-201 washout rate. In 1,265 consecutive patients having quantitatively analyzed stress-redistribution scintigraphy, 46 had a diffuse slow washout pattern with no or a maximum of one regional perfusion defect. Thirty-two underwent clinically indicated coronary angiography, and 23 (72%) of these were found to have three vessel or left main disease. Of 30 similar patients without a diffuse slow washout pattern and with no or a maximum of one perfusion defect, only 5 (17%) had extensive coronary disease. An independent relation between diffuse slow washout and extensive coronary disease was demonstrated by a Mantel- Haentzel chi-square analysis of a wide variety of other indexes of extensive disease. A diffuse washout abnormality, even in the absence of other scintigraphic, clinical or electrocardiographic indicators, carries a high predictive value for three vessel or left main coronary artery disease. The predictive value is maintained when the exercise level achieved is submaximal. Although an infrequent occurrence (3.6% of tested patients), a diffuse slow washout pattern without other scintigraphic indications of extensive coronary disease should lead to further diagnostic testing.

Coronary Angiography↗
PubMed1984

The St. Jude Medical bileaflet valve prosthesis. A 5 year experience.

A 5 year experience with the bileaflet St. Jude Medical valve is reported. Between March, 1978, and June, 1982, 198 patients received 233 such valves (90 mitral, 73 aortic, and 35 double mitral-aortic valve replacements). Total follow-up was 4,896 patient-months; survivors were followed up for 1 to 5 years (mean 35 months). Early (30 day) mortality was 6.6% overall and 11.1% after mitral, 2.7% after aortic, and 2.9% after double valve replacement. Total late mortality was 15.2%; the actuarial survival rate at 4 years was 67% after mitral, 79% after aortic, and 79% after double valve replacement. Ischemic mitral valve disease was associated with an early mortality of 26.7% and a 4 year survival rate of 34%; without this high-risk subset, early mortality was 3.3% and the 4 year survival rate was 77% after mitral valve replacement. A multivariate logistic regression model identified three preoperative patient characteristics associated with increased postoperative mortality: ischemic mitral valve disease (p less than 0.001), a depressed left ventricular ejection fraction (less than 55%; p less than 0.05), and advanced New York Heart Association class (IV; p less than 0.05). Valve-related complications occurred in 14 patients (3.4% per patient-year). There were no instances of primary structural failure or hemolysis. Thromboembolism (nine patients, 2.2% per patient-year) occurred more frequently after double (3.7% per patient-year) or mitral valve replacement (2.3% per patient-year) than after aortic valve replacement (1.3% per patient-year) and more frequently in 12 patients receiving aspirin and dipyridamole (6.5% per patient-year) than in 173 patients receiving warfarin (1.9% per patient-year). No thromboembolic event was fatal. Reoperation was necessary because of one valve thrombosis, one valve erosion, and two perivalvular leaks due to endocarditis; three of the four patients survived reoperation (one valve-related death, 0.5%). Of 154 patients alive at latest follow-up, 85% were in New York Heart Association Class I or II, and 90% had improved by at least one class. This intermediate experience with the St. Jude Medical valve indicates that, in addition to its previously demonstrated excellent hemodynamic performance, there have been no instances of primary structural failure or hemolysis. Warfarin anticoagulation is recommended in all patients.

Adolescent↗
PubMed1984

Mitral valve replacement: impact of coronary artery disease and determinants of prognosis after revascularization.

From 1969 to 1982, 419 patients underwent single mitral valve replacement; of these, 48% had associated coronary artery disease (9% single vessel, 8% double vessel, 28% triple vessel, 3% left main). In 216 patients with no associated coronary disease, in 179 patients with coronary disease that was revascularized, and in 24 patients with coronary disease that was not revascularized, the 30 day mortalities were 4.2%, 13.9%, and 29.2% (p less than .05) after valve replacement. Actuarial survivals at 8 years were 68%, 44%, and 15%, respectively (p less than .01), with 1 to 165 months of follow-up (mean 52). After matching the three cohorts of patients in age, sex, left ventricular ejection fraction, and valve lesion, the presence of associated coronary artery disease decreased long-term survival and revascularization improved survival (p less than .05 for both). Incidental coronary disease in patients with rheumatic mitral valve disease had a significant negative influence on survival if left unbypassed (p less than .05); after revascularization and valve replacement, the 30 day mortality was 7.3% and the 8 year survival was 52%. Coronary disease etiologically related to ischemic mitral regurgitation identified a high-risk group of patients, with a 30 day mortality of 19.6% and an 8 year survival of 37% after the combined procedure. A multivariate logistic regression model was used to determine which preoperative and intraoperative variables predicted early and late outcome after combined mitral valve replacement and coronary revascularization. Predictors of early death were advanced age (greater than 60 years), New York Heart Association functional class (IV), an ischemic etiology of the mitral valve disease, and a depressed left ventricular ejection fraction (less than 55%). Predictors of late death were triple-vessel or left main coronary disease, increased left ventricular end-diastolic volume (greater than 120 ml/m2), and depressed left ventricular ejection fraction (less than 55%). These findings highlight the important etiologic and prognostic role of coronary artery disease in patients requiring mitral valve replacement.

Adolescent↗
PubMed1983

Regional distribution of pulmonary blood volume: an index of pulmonary capillary wedge pressure determined from blood pool scintigraphy.

Progressive redistribution of pulmonary blood flow to the lung apices occurs with increasing degrees of left ventricular failure, and correlates with increasing pulmonary capillary wedge pressure (PCWP). If similar changes in pulmonary blood volume (PBV) occur, then technetium-99m equilibrium blood pool scintigraphy, by assessing relative distribution of PBV, may allow prediction of PCWP. Therefore 30 patients being monitored with pulmonary artery balloon flotation catheters underwent imaging. PCWP was compared with the average radioactive count density arising from apical (A) and basal (B) regions of interest within the right lung, expressed as an A/B ratio. Correlation was strong for patients imaged erect, either posteriorly (r = 0.864, p = 0.001) or in the 45 degrees left anterior oblique position (r = 0.842, p = 0.001), and only slightly less impressive for patients imaged supine (r = 0.678, p = 0.001). Especially when imaging was performed with patients erect, an A/B ratio greater than unity identified with high sensitivity (100%) and specificity (83 to 88%) an abnormally elevated PCWP (greater than 12 mm Hg). Moreover, directional changes in the A/B ratio reflected concomitant changes in PCWP after intervention. Thus, analysis of lung A/B radioactive count ratios obtained by equilibrium blood pool scintigraphy may be used to evaluate PCWP.

Adult↗
PubMed1983

Noninvasive detection of active pericardial bleeding using cardiac blood pool scintigraphy.

The diagnosis of active pericardial bleeding has traditionally depended on an invasive documentation by needle aspiration, angiography, or direct inspection. Blood pool scintigraphy performed in 2 patients just before and after the development of hemopericardium revealed unique images in which acute pericardial bleeding manifested itself by an additional blood pool adjacent to the cardiac chambers. With appropriate attention to technical factors, such distinctive images should be highly specific for active bleeding into the pericardial sac.

Aged↗
PubMed1983

Thermodilution cardiac output determination in hypothermic postcardiac surgery patients: room vs ice temperature injectate.

In normothermic patients, room temperature and ice temperature injectate have been shown to result in comparable thermodilution cardiac output measurements. However, room temperature injectate may give inaccurate results in hypothermic patients, particularly if the injectate volume is small, because of the lower injectate-to-blood temperature differential. We compared determinations of cardiac output using 10- and 5-ml volumes of room temperature (19-25 degrees C) injectate to those using 10-ml volumes of ice temperature (0-5 degrees C) injectate in 26 hypothermic (32.7 +/- 1.2 degrees C) postcardiac surgery patients. The cardiac outputs ranged from 1.8 to 5.3 L/min. Regression analysis demonstrated a close relationship between the cardiac outputs measured using room temperature injectate compared to those using ice temperature injectate (0.951 for the 10-ml volumes, 0.925 for the 5-ml volumes). We conclude that the room temperature injectate method is acceptable for determining thermodilution cardiac outputs in moderately hypothermic patients.

Adult↗
PubMed1983

Coronary artery stenoses. Relationship between angiographic severity and impact on mean diastolic pressure gradient.

Coronary angiography provides important anatomic information about coronary artery stenoses. However, it is unclear whether specific assumptions about hemodynamic impact can be made from the angiogram. We therefore studied the relationship between angiographic severity of coronary stenoses and the mean diastolic pressure gradient measured directly at coronary bypass operation. We studied 29 stenoses selected because they were the only lesions in a given vessel, they were well seen in two angiographic views, and there was no change in clinical status of the patient between angiographic and surgical procedures. Fourteen stenoses were in the left anterior descending artery, nine were in the right coronary artery, and six were in the left circumflex artery. Correlation between mean diastolic gradient and percent stenosis was good (r = 0.78, p = 0.001) and especially so for lesions in the left anterior descending artery (r = 0.84, p = 0.001). Lesions over 90% had a wide range of gradients, while lesions less than 90% tended to have more predictable gradients. Collaterals invariably identified vessels with stenoses causing major pressure gradients. History of myocardial infarction was associated with major gradients in supplying vessels. Length of stenosis was not an important influence on gradient over a stenosis. We conclude that in some defined instances, generalizations about hemodynamic (and presumed functional) impact of stenoses can be made from the angiographic assessment, but precise assumptions are not possible.

Adult↗
PubMed1983

Arrhythmias and conduction disturbances following cardiac operation for the removal of left atrial myxomas.

Between September, 1971, and April, 1982, 11 patients (seven female) with left atrial myxomas underwent surgical resection at Cedars-Sinai Medical Center. The tumors ranged in size from 4 to 9 cm (mean 6.3 cm) and were attached to the interatrial septum (four superiorly, four inferiorly), the free atrial wall (one posteriorly, one at the dome), or both (one). Although all patients were symptomatic preoperatively, arrhythmias were uncommon; only one had chronic atrial fibrillation, and two others had had single episodes of paroxysmal atrial fibrillation in the immediate preoperative period. Early postoperatively, all but one patient had episodes of atrial fibrillation (eight patients), atrial flutter (four patients), junctional rhythm (six patients), sinus arrest (two patients), or complete heart block (three patients). Ten patients required antiarrhythmic therapy, and two required permanent pacemaker implantation. After a mean follow-up of 48 months (range 7 to 124), seven patients continue to have episodic or chronic supraventricular arrhythmias, with only three patients not using antiarrhythmic drugs regularly. The pathophysiological basis for these arrhythmias is unclear, but some patients appear to have sustained injury to the sinus node or atrioventricular node, while others have developed interatrial or intra-atrial conduction delays. Attention should be directed to the basis of these arrhythmias and conduction disturbances, as surgical technique may be the major determinant of this early and late postoperative complication.

Adult↗
PubMedDate not supplied

Factors influencing myocardial salvage with primary angioplasty.

BACKGROUND: The purpose of this study was to evaluate the factors influencing the salvage of jeopardized myocardium in patients treated with primary angioplasty for acute myocardial infarction. METHODS AND RESULTS: This multicenter study involved 59 patients with acute myocardial infarction who underwent primary angioplasty without antecedent thrombolytic therapy and paired baseline (before angioplasty) and predischarge tomographic perfusion imaging by quantitative 99mTc-labeled sestamibi techniques for assessing the initial area at risk and eventual infarct size. Of the 59 patients who underwent primary angioplasty, Thrombolysis In Myocardial Infarction (TIMI) level 3 perfusion was restored in the infarct vessel in 54 patients (92%). On average, approximately one third of the left ventricular myocardial mass was initially jeopardized by the infarction in progress; eventual infarct size was 18% +/- 15% of the left ventricle; myocardial salvage was 16% +/- 17% of the left ventricle. Primary angioplasty salvaged 46% +/- 50% of initially jeopardized myocardium. Factors correlated with myocardial salvage included elapsed time from onset of pain to reperfusion, infarct location (anterior infarcts had more myocardial salvage than inferior infarcts), and residual flow to the infarct zone at preangioplasty baseline levels. In the five patients reperfused less than 2 hours from onset of pain, 80% of the jeopardized myocardium was salvaged. Myocardial salvage beyond 2 hours was much more variable. CONCLUSIONS: Primary angioplasty was highly effective at restoring normal perfusion in the infarct vessel and salvaging jeopardized myocardium. The myocardial salvage was highly variable and correlated with elapsed time to reperfusion, baseline residual flow to the infarct zone, and infarct location.

Adult↗
PubMedDate not supplied

Coronary angiographic rates after stress single-photon emission computed tomographic scintigraphy.

BACKGROUND: There is speculation that coronary angiography may be overused for the assessment of coronary artery disease. Because of its proved ability to differentiate high- and low-risk subsets of patients with coronary artery disease, myocardial perfusion scintigraphy should be an effective strategy in patient selection for angiography. This retrospective clinical study analyzed the relation between scintigraphic findings and subsequent angiography. METHODS AND RESULTS: Coronary angiographic rates were determined by following up on all stress single-photon emission computed tomographic (SPECT) myocardial perfusion studies performed in a cardiology practice nuclear laboratory during a 26-month interval. All patients were followed up for at least 3 months; mean follow-up was 8.9 months. Subsequent angiography was determined from catheterization laboratory logs, medical records, and telephone contact. Scintigraphic studies were graded according to presence or absence of reversible perfusion defects, affected coronary territories, and lung uptake of 201Tl. Scans were categorized high risk if more than two of the following three criteria were met: reversibility of left anterior descending or multivessel distributions or abnormal lung uptake of thallium. Of 4162 studies, 60% had reversible perfusion defects. Of such studies, 32% were followed up by angiography versus 3.5% without reversible defects. Among studies with reversible defects, the subsequent angiography rate was 60% for those showing high-risk reversibility, compared with 9% for all other studies demonstrating reversibility. Multivariate logistic regression identified high-risk reversibility (odds ratio 20.96) and any reversibility (odds ratio 8.22) as the strongest predictors of angiography. Other correlates of lesser statistical significance were angina and absence of prior infarction or coronary bypass. CONCLUSION: In this large retrospective study, the results of SPECT scintigraphy overpowered all other clinical and treadmill characteristics in determining the likelihood of subsequent coronary angiography. Only rarely were patients categorized as relatively low risk by scintigraphy referred for angiography. As such, SPECT scintigraphy as used in a private practice, self-referral environment appears to be effective in stratifying potential candidates for coronary angiography.

Adult↗
PubMedDate not supplied

Design and implementation of a nuclear cardiology testing facility in a private-practice cardiology office setting.

Nuclear cardiology services increasingly are being provided in private-practice cardiology office settings. Because training programs are hospital based, trainees in nuclear cardiology may find only limited guidance on how to set up a private-practice nuclear laboratory. Furthermore, there is no literature to date advancing "models" for such facilities that might be useful for practice managers. The purpose of this review is to address common issues related to setting up and administering a nuclear cardiology laboratory in a private-practice cardiology office.

Cardiology↗