Left ventricular performance after coronary artery bypass surgery. Prediction of functional benefit.

Global left ventricular performance (ejection fraction) and regional function were studied by rest-exercise radionuclide ventriculography in 36 patients before and after (23 +/- 8.5 wk) they had coronary artery bypass surgery for stable angina pectoris. The exercise ejection fraction was less than the resting ejection fraction before surgery (n = 36,p = 0.006), but not after surgery. The degree of postoperative improvement correlated with the degree of preoperative dysfunction (r = 0.55, n = 36, p less than 0.001). Improvement was most likely to occur if exercise-induced dysfunction was present preoperatively (n = 15,p = 0.001), even with old myocardial infarction. Regional dysfunction during preoperative exercise was also likely to improve postoperatively (n = 18, p = 0.001). Protocol design is important in determining the results and their interpretation. Matching postoperative exercise loads to preoperative loads and using regional analysis with two imaging projections improved judgment of the results. Regional dysfunction was commoner than global dysfunction and was less sensitive to workloads than was ejection fraction. This study shows that coronary artery bypass surgery can improve left ventricular performance on exercise if preoperative tests indicate the presence of ischemia-induced dysfunction.

Lymphoscintigraphy as an adjunctive procedure in the perioperative assessment of patients undergoing microlymphaticovenous anastomoses.

Microlymphaticovenous anastomoses provide a potential for reducing lymphedema of the upper extremity complicating radical mastectomy or irradiation. Lymphoscintigraphy is a valuable investigative modality in the perioperative evaluation of patients undergoing this surgical procedure. The radionuclide studies provide information regarding structural change and physiologic derangement with a low radiation dose to the patient. It is a simple, painless procedure requiring minimal skill and no surgical intervention. In addition, a reproducible method for preparing a radiocolloid suitable for lymphatic imaging using an approved drug as a precursor has been developed.

Radionuclide stroke count ratios for assessment of right and left ventricular volume overload in children.

The ratio of left ventricular to right ventricular stroke counts measured by radionuclide angiography has been used in adults to estimate the severity of left-sided valvular regurgitation. The validation of this technique in children for assessment of right and left ventricular volume overload is reported herein. Radionuclide stroke count ratios in 60 children aged 0.5 to 19 years (mean 11) were determined. Based on their diagnoses, the patients were divided into 3 groups: (1) normal--40 patients with no shunts or valvular regurgitation, (2) left ventricular volume overload--13 patients with mitral or aortic regurgitation, or both, and (3) right ventricular volume overload--7 patients, 2 with severe tricuspid regurgitation, 3 with atrial septal defects, and 2 with total anomalous pulmonary venous drainage. The radionuclide stroke count ratio clearly differentiated these groups (p less than 0.05): normal patients had a stroke count ratio of 1.04 +/- 0.17 (mean +/- 1 standard deviation), the left ventricular volume overload group had a stroke count ratio of 2.43 +/- 0.86, and the right ventricular volume overload group had a stroke count ratio of 0.44 +/- 0.17. In 22 of our 60 patients, radionuclide stroke count ratios were compared with cineangiographic stroke volume ratios, resulting in a correlation coefficient of 0.88. It is concluded that radionuclide ventriculography is an excellent tool for qualitative and quantitative assessment of valvular regurgitation in children.

Thallium-201 uptake in variant angina: probable demonstration of myocardial reactive hyperemia in man.

Myocardial thallium scintigraphy was performed in four subjects with variant angina and in one subject with isolated, fixed coronary obstruction. Three subjects with variant angina had short episodes of ischemic ST-segment elevation that lasted 20--100 seconds. Thallium scintigrams demonstrated excess uptake in regions judged to be ischemic by angiographic and electrocardiographic criteria. Two subjects, one with variant angina and the other with a fixed coronary lesion, had prolonged episodes of ischemia that lasted 390--900 seconds. Both had reduced thallium uptake in the ischemic regions. We conclude that myocardial reactive hyperemia is the cause of excess thallium uptake in patients with variant angina who have short episodes of myocardial ischemia.

Radionuclide ventriculography for assessment of absolute right and left ventricular volumes in children.

We determined absolute right and left ventricular volumes and cardiac output from the equilibrium radionuclide angiogram in 26 children, ages 3 months to 18 years, with diverse types of heart disease. We validated these results by comparing them with left ventricular (20 patients) and right ventricular (16 patients) cineangiographic volumes and cardiac output. Radionuclide volumes and cardiac outputs were determined in two ways: by a geometric method (area-length for left ventricle, Simpson's rule for right ventricle) and by a count-based method (correcting ventricular regional counts for frame duration, acquisition time, venous blood counts and attenuation). Both methods for estimating left ventricular end-diastolic volume compared favorably with cineangiography (correlation coefficients greater than 0.90). The count-based method also correlated well for the right ventricle. End-systolic measurements were not possible. Count-based assessment of cardiac output also correlated well with cineangiographic values. We conclude that right and left ventricular volumes and cardiac output can be reliably measured in children with equilibrium radionuclide ventriculography.

Radionuclide evaluation of right and left ventricular function in children: validation of methodology.

Validation of an equilibrium radionuclide technique for assessing right and left ventricle function has not been reported in children with heart disease. Resting equilibrium radionuclide ventriculograms were performed in 71 children with diverse types of heart disease (age range 1 to 19 years, mean 10.2) with exercise studies in 52 of the children. Cardiac catheterization was performed in 39 of the 71 children within 2 weeks of radionuclide study. Resting left and right ventricular ejection fractions from radionuclide study and catheterization were compared by linear regression analysis: right ventricular ejection fraction, r = 0.83; left ventricular ejection fraction, r = 0.90. Interobserver correlations for right and left ventricular ejection fractions were 0.93 and 0.94, respectively. With exercise, the interobserver correlations for right and left ventricle were 0.97 and 0.92, respectively. Thus, right and left ventricular ejection fractions showed good correlations with cineangiographic ejection fractions. Furthermore, it was possible to perform this study in exercising children with no deterioration in interobserver correlations. This technique can provide important information on ventricular function in children and aid in long-term evaluation of current methods of treatment for several congenital heart defects.

Radionuclide ventriculography: evaluation of automated and visual methods for regional wall motion analysis.

Regional wall motion (RWM) abnormalities are sensitive indicators of left ventricular (LV) dysfunction, but quantitation of RWM with gated radionuclide ventriculography (RVG) has been limited, particularly in the left anterior oblique (LAO) projection. Regional LV performance was studied in 18 patients undergoing LAO RVG immediately prior to contrast ventriculography (CVG). Wall motion was analyzed by semiautomated and visual methods using several coordinate systems. For semiautomated methods, RVG and CVG wall motion were closely related in the two 90 degrees polar sectors at the apex and posterior wall (r = .85) and in the five 45 degrees polar sectors from midseptum through posterior wall (r = .82). The basal sectors on RVG had weak relationship to CVG, due to adjacent vascular structures. Semiautomated and visual grades for polar sectors on both CVG and RVG were closely related (r = .88- .94). Measured regional wall motion on LAO RVG compared favorably with near-simultaneous CVG in nonoverlapping portions of the LV and allowed objective quantitation of regional LV performance.

Management of major thromboembolic complications of umbilical artery catheters.

Over the last 9 yr approximately 4000 infants have had physiologic monitoring with UAC at Vanderbilt University Medical Center. A larger number of them had minor ischemic complications prompting removal of the catheter, but 41 patients had major thromboembolic problems requiring varying degrees of surgical management. The place of surgery is clear in patients with catheter emboli or bleeding due to vascular avulsion related to catheter removal. Patients with arterial occlusion distal to the femoral artery may be treated expectantly although significant skin loss may occur. Occlusions at the femoral level allow limb survival, but the long-term outlook is not known; perhaps these patients may better be subjected to femoral thrombectomy in the future. Peripheral pulses are not normal early and Doppler studies suggest that collateral circulation is responsible for limb survival. Whether this will be sufficient to support adequate limb growth and function remains to be seen. Patients with signs of aortoiliac or mesenteric occlusion should be rapidly investigated and operated upon if survival is to be obtained. This study suggests that an aggressive surgical approach is in order. Computer-assisted radionuclide flow studies are helpful in diagnosing major aortic occlusion, as well as for followup.

Experimental study of double staple lines in gastric partitions.

Results of this study suggest that, when separated by 1 centimeter, the gastric wall situated between the two staple lines is relatively ischemic compared with the gastric wall outside the staple lines. The potential for perforation within this isolated segment is consequently greater. Therefore, placing two rows of staples 1 centimeter apart is dangerous and should be avoided. On the other hand, the gastric partitions can be safely reinforced by placing a double row of staples immediately adjacent to each other. Although placing two rows of staples 2 centimeters apart may be safe, there is little, if any, reinforcement of the proximal suture line, and it is not recommended.

Comparison of radionuclide and contrast ventriculography for detection and quantitation of regions of myocardial ischemia in dogs.

Radionuclide and contrast ventriculography were evaluated for their ability to estimate myocardial ischemia. In 14 closed-chest, sedated dogs, a small and larger region of ischemia were produced by inflating balloon occluders on the left anterior descending coronary artery. The systemic arterial pressure, atrial-paced heart rate, global ejection fraction by radionuclide and contrast ventriculography, regional wall-motion abnormalities (as the percentage of abnormally contracting segments), and regional myocardial blood flow (using the microsphere technique) were measured during an initial control period, two separate ischemic periods, and a final control period. The regional ischemic weights based on myocardial blood flow ranged from 0 to 38.5 g and were grouped as zero, small (range 0 to less than 10 g, mean 3.40 g), and large regions of ischemia (greater than 10 g, mean 24.8 g). Regional wall-motion abnormalities were sensitive qualitative indicators of ischemia. Receiver operating characteristic analysis showed that both ventriculographic methods were highly sensitive, specific, and accurate for detecting regional ischemia. Contrast ventriculography was slightly superior for detecting small regions less than 4 g, but the methods were equal for regions greater than 4 g. The arterial pressure and heart rate were unchanged during ischemia. For small regions of ischemia, the global ejection fraction did not fall using either the contrast or radionuclide technique, but it fell significantly when large regions were produced. There was a quantitative relationship between the percentage of abnormally contracting segments and the grams of myocardial ischemia (for radionuclide ventriculography, r = 0.65, P = 0.003, and for contrast ventriculography, r = 0.75, P less than 0.001), but for many small regions of ischemia, wall-motion changes were greater than anticipated, suggesting hypofunction of the continguous normal tissue. This study demonstrated that both radionuclide and contrast ventriculography were quite sensitive and specific for detecting measured amounts of regional ischemia. The functional changes resulting from ischemia are quantitatively related to the extent of regional ischemia, small areas resulting in regional wall motion abnormalities, and large areas producing both reduced global ejection fraction and wall motion changes.

Radionuclide evaluation of renal artery dilatation.

Radionuclide studies were sued in three patients to evaluate renal perfusion and function within 24 hours following transluminal dilatation. In one patient, technetium-99 m pertechnetate showed good renal perfusion one and 12 hours after a post-dilatation arteriogram had shown a renal artery intimal defect. Improved clearance of iodine-131 ortho-iodohippurate from the blood demonstrated an increase in renal function 18 hours following dilatation of a stenosis at a renal allograft anastomosis in the second patient, while technetium-99 m-labeled DTPA showed an improved total glomerular filtration rate 24-hours after dilatation of a saphenous vein bypass graft in the third patient. It was concluded that renal radionuclide studies are of benefit in evaluating patients in the immediate post-dilatation period.

Gallium bone scan in myelofibrosis: case report.

When gallium is injected into a patient who has received many transfusions, the resultant scan appears similar to a bone scan with renal excretion. This case report presents a 51-year-old man with myelofibrosis and myeloid metaplasia. Gullium-67 and 52Fe scans with 99mTc-pyrophosphate bone scintigrams are included.