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Prediction of reversible myocardial dysfunction by positron emission tomography, low-dose dobutamine echocardiography, resting ECG, and exercise testing.

We studied different algorithms to identify patients with heart failure who could potentially benefit from revascularization. Thirty-five coronary artery bypass (graft) patients with an ejection fraction of 35 +/- 7% underwent preoperative 18F-fluoro-2-deoxyglucose positron emission tomography (PET), low-dose dobutamine echocardiography (LDDE), and exercise testing. Follow-up by echocardiography and coronary angiography was performed 6 months after coronary artery bypass grafting. The sensitivity for prediction of reversible myocardial dysfunction was highest for PET and for ST depression or angina pectoris during exercise testing (100 and 93%, p = NS), 71% for LDDE (p < 0.05 vs. PET), and 50% for resting ECG (p < 0.02 vs. PET and exercise test). The specificity did not differ between LDDE (81%), PET (67%), and resting ECG (71%), but was lowest for exercise testing (33%; p < 0.02 vs. PET, LDDE, and resting ECG). Accuracies were: PET 80%, LDDE 77%, exercise testing 62%, and resting ECG 58% (p < 0.05 vs. PET). In patients with a negative exercise test, recovery was unlikely, and further viability testing may not be needed. In patients with a positive test, recovery may occur, and additional PET or LDDE should be performed. In these cases, PET with an 18F-fluoro-deoxyglucose uptake of > or =70% as the criterion for viability yields optimum diagnostic characteristics. This strategy awaits further evaluation in larger patient populations with heart failure.

Aged↗

Visualization of the temporal bone of the Chinese Visible Human.

Temporal bone anatomy is very difficult to understand. After dataset acquisition of the first Chinese Visible Human, we processed the two-dimensional images to build a digitized visible model of the temporal bone and explore the role of virtual endoscopy in the inner ear. On a SGI workstation three-dimensional computer reconstructions of the ear were generated from the Chinese visible human dataset, viewing the middle and inner ear imitating the traditional otoscopy. The three-dimensional data of the temporal bone were then converted to STL format, and the temporal bone replica were fabricated with rapid prototyping by laminated object manufacturing. The virtual model of the ear was successfully completed, and the virtual endoscopy improved three-dimensional visualization of the middle and inner ear. Physical replica of the temporal bone were built with paper; the accuracy was +/-0.2 mm. The reconstructed model and the replica of the temporal bone can be used to make preoperative plans in the complicated otoneurosurgical operations, allowing various surgical exercises to be carried out on the three-dimensional stereophysical model. The virtual endoscopy stands as a promising new visualization technique for elucidation of the middle and inner ear and reveals a tremendous potential in both clinical and educational settings, providing morphological data for the image diagnosis and otoneurosurgery.

Anatomy, Cross-Sectional↗

Computer-derived treadmill exercise score quantifies the degree of revascularization and improved exercise performance after coronary artery bypass surgery.

A computer-derived treadmill exercise score (TES) that quantifies the severity of the ischemic ST response to exercise was used to detect noninvasively graft occlusion or the progression of new lesions after coronary artery bypass surgery. Three months after surgery TES completely normalized in 68% of patients and improved by more than 70% in another 18% of patients, thus reflecting excellent improvement in exercise-induced ischemia in 87% of patients. Surgical results correlated well with completeness of revascularization as shown by repeat coronary angiography. When TES, done serially up to 4 years after surgery, remained unchanged, grafts were patent and no new critical lesions had occurred. Deterioration in TES always predicted either late graft occlusion or appearance of new, high-grade lesions in the native vessels. Thus TES provides a new, accurate method that quantifies the ischemic response to exercise and detects graft occlusion or new obstructive lesions in the native coronary arteries.

Arterial Occlusive Diseases↗

A stepwise strategy for coronary risk assessment for noncardiac surgery.

Physicians should adapt a systematic approach to cardiac risk stratification for patients being considered for noncardiac surgery, involving clinical evaluation, functional assessment, and surgical risk assessment for all patients and then deciding which patient needs to undergo noninvasive testing, coronary angiography and revascularization, perioperative monitoring, and aggressive postoperative care.

Coronary Disease↗

Variant petrotympanic fissure as possible cause of an otologic complication during TMJ arthroscopy. A case report.

In this reported case, a variant petrotympanic fissure--opening at the height of the orifice of the Eustachian tube into the hypotympanon--was identified by high resolution computed tomography (CT) as the possible cause of a tympanic membrane perforation. Inner ear function was preserved by an otosclerotic stapes which prevented destruction of the labyrinth. The perforation was closed by a myringoplasty and was to be followed by a stapedectomy after six months to restore normal hearing. Surgeons performing temporomandibular joint arthroscopy should be aware that in a small percentage of patients a variant anatomy of the tympanic plate exists and, therefore, great care must be exercised in the manipulation of instruments near this structure. A preoperative high resolution CT with thin slices of the temporal bone might allow identification of these high risk patients.

Adult↗

Prognostic value of stress echocardiography in stable angina or after myocardial infarction.

Stress echocardiography is increasingly used for the assessment of coronary artery disease and is valuable in the treatment of patients with known disease as well. Although several studies are available on the accuracy of stress echocardiography in the detection of coronary artery disease and evaluation of its severity, studies on the use of this technique for evaluation of prognosis are just now emerging. Over the past decade, few studies have investigated its prognostic value in different patient populations. The versatility and advantage of stress echocardiography lie in the fact that it provides information on both resting ventricular function and stress-induced ischemia, two important determinants of cardiac events. Exercise echocardiography with the bicycle or posttreadmill approach is used in subjects who can exercise and provides important additional prognostic data from physiologic exercise variables. In patients unable to exercise, pharmacologic stress echocardiography with dobutamine or vasodilators is used. Stress echocardiography has been shown to identify different populations of patients at risk of cardiac events, including those with stable or suspected coronary artery disease, those with acute myocardial infarction, and those scheduled for major noncardiac surgery. In the early postinfarct setting, exercise and vasodilator stress have been used more often, whereas dobutamine echocardiography has been used predominantly at low doses for the assessment of residual myocardial viability. This review focuses on recently published investigations evaluating the prognostic effect of stress echocardiography in patients with stable coronary artery disease or acute myocardial infarction.

Angina Pectoris↗

The effect of operative position and short-segment fusion on maintenance of sagittal alignment of the lumbar spine.

STUDY DESIGN: A retrospective radiographic assessment of the maintenance of sagittal alignment in patients undergoing short-segment instrumented fusions in a knee-chest position. OBJECTIVE: To determine whether the use of the knee-chest position adversely effects the maintenance of lumbar sagittal alignment in patients undergoing short-segment instrumented fusions of the lumbar spine. SUMMARY OF BACKGROUND DATA: Previous authors have demonstrated that lumbar lordosis is reduced in the knee-chest position, but it is unknown whether the kneeling position adversely affects the maintenance of lumbar lordosis in short-segment instrumented fusions during the follow-up period. METHODS: Twenty-eight patients (17 men and 11 women, 20-72 years of age) were reviewed retrospectively, having undergone short-segment fusions in the kneeling position. Seven patients underwent posterior spinal fusion from L4 to L5, 13 patients from L5 to S1, and 8 patients from L4 to S1. Transpedicular instrumentation and autogenous iliac crest bone grafting was used in all cases. Radiographs were assessed for sacral tilt, lumbar lordosis, and intervertebral angulation. Data were analyzed with repeated measures analysis of variance. RESULTS: The minimum follow-up period was 33 months. For all 28 patients, lumbar lordosis measured 51 degrees before surgery, 37 degrees during surgery (P = 0.0001), and 50 degrees after surgery (P = 0.6135). In patients undergoing L4-S1 posterior spinal fusion, sacral tilt measured 49 degrees before surgery and 45 degrees after surgery (P = 0.039). Although overall lumbar lordosis was maintained, lordosis was shifted proximally in the lumbar spine, increasing at L1-L4 from 19 degrees before surgery to 24 degrees after surgery, while decreasing at L4-S1 from 32 degrees before surgery to 26 degrees after surgery. CONCLUSION: Overall lumbar lordosis is well maintained in patients undergoing short-segment instrumented fusion in the kneeling position. With compensatory lordosis being shifted proximally and sacral tilt not returning to the preoperative status in L4 to S1 fusions, caution should be exercised in using the kneeling position for longer instrumented lumbar fusions.

Adult↗

Propranolol dosage in thyrotoxicosis.

Eighteen thyrotoxic patients receiving chronic treatment with propranolol (160 mg/day) were studied to determine the relationship between plasma propranolol concentration and drug effect. There was a considerable interindividual variability in both the plasma propranolol steady state concentration and the degree of beta-adrenergic blockade. The plasma propranolol steady state concentration correlated significantly with both beta-adrenergic blockage and weight change but not with the degree of subjective improvement. In a group of 40 patients, including 10 severely thyrotoxic patients, who had the dosage of propranolol titrated objectively preoperatively to bring about a greater than 25% reduction in exercise heart rate at the end of a dosage interval, no case of thyroid storm was encountered. Many patients, the younger and severely thyrotoxic in particular, require doses in excess of 160 mg/day to achieve this degree of beta-adrenergic blockade.

Adolescent↗

[The blood flow in the peripheral arterial occlusive disease--investigation by 133Xe clearance method].

The blood flow in the lower extremities was investigated before and after surgery on patients with peripheral arterial occlusive disease by 133Xe clearance method in order to evaluate results of sympathectomy and reconstructive arterial surgery. Sixty-four patients, 54 with arteriosclerosis obliterans, 7 with thromboangiitis obliterans and 3 with Raynaud's disease were divided in two groups. Skin blood flow was measured in one group and muscle blood flow in another one. Flow was measured at rest in the former, while at rest, during and after exercise in the latter. The following results were obtained. The preoperative clearance was correlated with severity of the disease. Skin blood flow increased after sympathectomy more than reconstructive arterial surgery. Muscle blood flow before and after reconstructive surgery increased adequately at rest and under reactive hyperemia. The 133Xe clearance method is a simple and reliable test for evaluation of the blood flow in the extremities.

Adult↗

The relative importance of incompetent communicating veins in the production of varicose veins and venous ulcers.

To investigate the possible anatomic and hemodynamic reasons for the variability in response to surgery for venous insufficiency (a 50% ulcer recurrence rate following ligation of incompetent perforating veins), we performed phlebography and venous pressure measurements in 109 legs of 77 patients and in 30 healthy volunteers. Patients were divided into five groups: saphenofemoral incompetence alone (group 1), saphenopopliteal incompetence (group 2), incompetent lower leg communicating veins alone (group 3), calf communicating veins and saphenous incompetence (group 4), and postthrombotic limbs (group 5). Patients in groups 1 through 4 had phlebographically normal deep veins. As compared to the normal controls (68%), preoperative pressure measurements revealed a significantly smaller pressure fall during exercise (deltaVPex) in all groups, which was the least marked in groups 3 (26%) and 5 (17%). These latter two groups failed to increase their pressure fall with thigh tourniquet. deltaVPex 3 months after operation demonstrated normalization in groups 1, 2, and 4 (52%, 57% and 59% respectively). Groups 3 and 5 improved little following surgical ligation. Whenever saphenous vein incompetence coexists with lower leg communicating vein incompetence, the former appears to be the dominant cause of the pressure abnormalities. Based on venous pressure measurements and phlebography, patients with normal deep veins and who increase their deltaVPex with a thigh tourniquet should respond favourably to orthodox surgical ligation of the saphenofemoral or saphenopopliteal junction. By contrast, if no change in deltaVPex is noted in patients with incompetent perforating veins and the deep veins look abnormal on the phlebogram, then ligation of the incompetent communicating veins would appear to be associated with a high recurrence rate.

Adult↗