An estimate of the prevalence of reversible left ventricular dysfunction in patients referred for coronary artery bypass surgery

Background  The prevalence of reversible left ventricular function through revascularization has been difficult to assess because of the referral bias inherent in patients undergoing viability-targeted preoperative testing. Methods and Results  Rest and exercise gated equilibrium radionuclide angiography was performed in 86 patients within 6 months before and any time after coronary artery bypass. Clinical characteristics were recorded for each patient before each of the two radionuclide ventriculograms. Global left ventricular ejection fraction (LVEF) was calculated for each patient at rest. A definite change in LVEF was defined as 0.08 or more points and a probable change as 0.04 or more points. Only patients with a resting LVEF of 0.50 or less were eligible for the study. There was no significant group change in LVEF (0.39±0.08 before surgery vs 0.38±0.11 after surgery; difference not significant). However, a definite improvement in LVEF was seen in 18 patients (21%) and a probable change in an additional 10 (12%). Consequently, one third of the patients had at least a probable improvement in resting left ventricular function. These prevalences were not related to any change in medical therapy. Conclusion  According to a test not specifically designed to evaluate myocardial viability, the prevalence of reversible left ventricular dysfunction is not uncommon, occurring in up to one third of patients referred for coronary revascularization.     

Technetium-99m teboroxime scintigraphy. Clinical experience in patients referred for myocardial perfusion evaluation

In order to evaluate the clinical value of a new myocardial perfusion tracer, a series of 30 patients (25 male, 5 female, mean age 56 years) referred for thallium 201 stress/redistribution scintigraphy has been studied using stress/rest (n = 7) or rest/stress (n = 23) protocols with technetium 99m teboroxime (Cardiotec SQUIBB). In all cases coronary artery disease was known or highly probable, with a history of myocardial infarction in 18 cases. Medical treatment was not discontinued at the time of stress testing, and coronary angiography was available in 27 patients. Exercise tests for both tracers were carried out on a bicycle ergometer during the same day, and the levels of exercise achieved for the 201Tl study were very similar to those achieved for 99mTc-teboroxime. Studies performed in three planar projections were evaluated using a model with four territories: septal and anterior assumed to correspond to the left anterior descending artery, lateral and latero-posterior (left circonflex), inferior and posterior (right coronary artery) and apex. Classification of results was: normal, ischaemic, infarcted and infarcted with ischaemia. On comparison with the 201Tl results, agreement was found in 86% (37/43) of normal regions and in 82% (63/77) of abnormal regions. Relative to documented coronary artery lesions (27 patients), sensitivity and specificity of 201Tl and 99mTc-teboroxime for exact correspondence between arteries and territories were respectively: 201Tl: sensitivity 64%, specificity 60%; 99mTc-teboroxime: sensitivity 62%, specificity 77%.(ABSTRACT TRUNCATED AT 250 WORDS)     

Predicting the outcome of distraction osteogenesis by 3-phase bone scintigraphy.

Distraction osteogenesis is an effective method for lengthening long bones and filling bone defects that result from bone resection. Insufficiency of bone consolidation in the distraction segment is problematic. In this study, we examined whether 3-phase bone scintigraphy can predict the outcome of distraction osteogenesis. We also investigated the effects of chemotherapy and surgical treatment on distraction osteogenesis. METHODS: We performed 3-phase bone scintigraphy on 60 patients (9 high-grade malignant bone tumors as group A, 11 low-grade malignant or benign tumors as group B, 40 nontumoral conditions as group C) with distraction osteogenesis at the lengthening phase of the long bones. By setting the region of interest on the distraction segment and contralateral normal area, we calculated the perfusion index (PI), the uptake ratio of the blood-pool image (BPR), and the uptake ratio of the delayed image (DR). Patients were classified into poor and good consolidation groups from the radiographic findings of the distraction segment. RESULTS: Good to fair correlations were obtained between the PI and BPR, the PI and DR, and the BPR and DR (r = 0.65, 0.45, and 0.57, respectively). The PI and BPR indicated no significant differences among group A-C (1.7 +/- 0.6, 2.1 +/- 0.7, and 1.8 +/- 0.8 in PI, respectively; 1.8 +/- 1.1, 1.9 +/- 0.5, and 2.0 +/- 0.7, in BPR, respectively). The DR of group A (2.4 +/- 1.2) was significantly lower than that of group B (6.3 +/- 1.8; P = 0.001) and group C (5.9 +/- 2.8; P < 0.001). Eleven patients were classified in the poor consolidation group. The other 49 patients showed good consolidation. The poor consolidation group showed lower values in all indices obtained by 3-phase bone scintigraphy than the good consolidation group. The optimal cutoff levels, sensitivity, specificity, and accuracy of each index for detection of patients with poor consolidation were as follows: 1.1, 36%, 90%, and 80% in the PI, respectively; 1.2, 55%, 94%, and 87% in the BPR, respectively; and 2.2, 82%, 96%, and 93% in the DR, respectively. CONCLUSION: Three-phase bone scintigraphy is a promising method for the assessment of distraction osteogenesis. The delayed image of 3-phase bone scintigraphy, especially, is an excellent modality for predicting the outcome of distraction osteogenesis.     

Incidence of adrenal masses in patients referred for renal artery stenosis screening MR

RATIONALE AND OBJECTIVES: Prior work has shown the efficacy of magnetic resonance (MR) in renal artery stenosis evaluation. The increasing role of renal artery stenosis in the differential diagnostic evaluation of hypertension raises the question of whether MR should be used as a screening modality. This project evaluated the additional potential benefits of MR by determining the incidence of adrenal masses in this selected population. METHODS: A 2-year retrospective study analysis of patients who failed to respond to antihypertensive medical management and were referred for renal MR for hypertension amassed 77 subjects ranging in age from 18 to 88 years. A masked analysis for adrenal masses was performed on this data set. Magnetic resonance techniques included T2-weighted turbo spin-echo (repetition time [TR] 2000-4000 ms, echo time [TE] 80-100 ms, turbo factor 2-16), T1-weighted spin-echo (TR 200-500 ms, TE 10-30 ms), gradient-echo time-of-flight (TR 26 ms, TE 6.9 ms, 40 degrees flip angle, 2 excitations), and dynamic gadopentetate dimeglumine-enhanced MR angiography (three-dimensional gradient recalled echo, TR 10 ms, TE 3 ms, 40 degrees flip angle, 1 excitation). RESULTS: Thirty-three patients had renal artery disease, 44 had normal renal arteries, and 7 had adrenal masses. Forty-three percent of patients who underwent renal MR had disease of the renal arteries detected, and 9% of patients referred for MR had adrenal masses that would have been missed with scintigraphy and/or angiography, of which 57% were responsible for hypertension. CONCLUSIONS: The ability to evaluate renal artery and adrenal anatomy globally can be useful, as exemplified in the current series, and the adrenals should be examined carefully in any renal MR in a hypertensive patient.     

Diagnostic accuracy of MDCT coronary angiography in patients referred for heart valve surgery

Purpose

The aim of our study was to evaluate the role of multidetector-row computed tomography (MDCT) in patients referred for heart valve surgery. We studied the diagnostic performance of CT coronary angiography (CTCA) compared with conventional coronary angiography (CCA) before valve surgery.

Materials and methods

During a 13-month period, 55 consecutive patients under evaluation for aortic (40/55) or mitral valve (15/55) disease before potential valve replacement underwent CTCA using a 64-detector-row scanner within 2 months of CCA for comparative purposes. All 17 major coronary artery segments were evaluated by one observer and compared with the reference standard. Patient-based, vessel-based and segment-based analyses of the data were performed.

Results

Prevalence of significant coronary artery disease, defined as having at least one stenosis ≥50% per patient, was 36%. On a patient-based analysis, sensitivity, specificity and positive and negative predictive values were 100%, 91%, 83% and 100%, respectively.

Conclusions

The diagnostic accuracy of 64-row CTCA for ruling out the presence of significant coronary stenoses in patients undergoing valve surgery is excellent and allows CTCA to be used as a gatekeeper for invasive CCA in these patients. MDCT is a necessary preoperative examination that provides useful information for identifying potential operative complications of surgical procedures.     

Nuclear imaging as a screening test for patients referred for intraarticular facet block

Our experience, in a group of 25 patients with chronic low back pain, shows that nuclear imaging of the spine with 99mTc-methylene diphosphonate is of no benefit in predicting the sites at which intraarticular facet blocks may be successful.     

Techniques for reducing interventional neuroradiologic skin dose: tube position rotation and supplemental beam filtration.

PURPOSETo limit the side effects of interventional neuroradiologic radiation, such as epilation, by applying a technique involving tube position rotation and by adding a supplemental inexpensive primary beam filter; and to show the dose effect of modifying technical factors.METHODSCombined skin dose from fluoroscopy and digital subtraction angiography was measured with an array of 16 thermoluminescent dosimeters during interventional neuroradiologic procedures in 12 control subjects, in 18 patients whose procedures included addition of an inexpensive primary beam filter (0.5 mm aluminum/0.076 mm copper), and in 10 patients in whom the tube position was rotated, additional primary beam filtration was used, and close attention was paid to technique.RESULTSMaximum thermoluminescent dosimetric measurements obtained with existing machine filtration ranged from 0.31 to 2.70 Gy in the control group (mean, 1.51 +/- 0.88); 0.25 to 2.42 Gy in the group with additional filtration alone (mean 0.96 + 0.64; average dose reduction, 36%); and 0.13 to 1.23 Gy in the group with additional filtration, tube position rotation, and close attention to technique (mean, 0.58 +/- 0.34; average dose reduction, 63%). Differences were statistically significant.CONCLUSIONSGreater than 50% skin dose reductions were documented during interventional neuroradiologic procedures by combining tube position rotation, supplemental primary beam filtration, and technical modifications.     

Circumferential segmental vessel-wall enhancement on black blood MRI in patients referred for the evaluation of vasculopathy

BackgroundHigh resolution intracranial vessel wall magnetic resonance imaging, or black blood MRI, has recently gained traction as an adjunct to computed tomography angiography, magnetic resonance angiography, and digital subtraction angiography in the characterization of atherosclerosis, vasculitides, and inflammatory changes in the aneurysm wall. However, the occurrence of uniform circumferential segmental arterial vessel wall enhancement (CSWE) in patients without these diagnoses has not previously been studied. The purpose of this study is twofold: 1) to evaluate the prevalence of CSWE in the major intracranial arteries in patients without vasculitides, symptomatic atherosclerosis, or aneurysmal subarachnoid hemorrhage and 2) to determine the association, if any, between such enhancement and risk factors for cerebrovascular atherosclerotic disease.Materials & methodsA retrospective study of vessel wall magnetic resonance imaging examinations was performed to evaluate for CSWE in 26 patients without known vessel wall pathology such as aneurysms or vasculitides and intracranial hemorrhage. Further evaluation of CSWE association with major intracranial atherosclerotic disease risk factors including hypertension, hyperlipidemia, diabetes mellitus and cigarette smoking was performed.Results and conclusion46% of the cohort of patients demonstrated CSWE. Among the patients with CSWE, there was increased prevalence of CSWE in the posterior circulation vasculature with particular predilection to the V4 vertebral artery segments (92%), although there was greater association of anterior circulation CSWE with risk factors for atherosclerosis. Patients with anterior circulation CSWE also demonstrated the most number of segments with CSWE. We therefore propose that CSWE, particularly in the anterior circulation, may portend early atherosclerosis.     

Impact of diabetes mellitus on prediction of clinical outcome after coronary revascularization by 18F-FDG SPECT in patients with ischemic left ventricular dysfunction.

Nuclear imaging using (18)F-FDG is an established method for the noninvasive assessment of myocardial viability. Data on the value of (18)F-FDG imaging in patients with diabetes mellitus are scarce. The aim of this study was to assess whether, in patients with diabetes mellitus and ischemic left ventricular (LV) dysfunction, (18)F-FDG imaging can predict improvement of LV function and heart failure symptoms after coronary revascularization. METHODS: A total of 130 consecutive patients with ischemic LV dysfunction who were already scheduled for surgical revascularization were studied; 34 of the patients had diabetes mellitus. All patients underwent radionuclide ventriculography to assess left ventricular ejection fraction (LVEF), resting 2-dimensional echocardiography to identify dysfunctional myocardial tissue, and dual-isotope (18)F-FDG/(99m)Tc-tetrofosmin SPECT after oral administration of acipimox. Nine to 12 mo after coronary revascularization, radionuclide ventriculography and echocardiography were repeated. An improvement in LVEF by at least 5% was considered significant. RESULTS: (18)F-FDG SPECT demonstrated that 610 (50%) of 1,212 dysfunctional segments were viable. Patients with and without diabetes mellitus had a comparable number of dysfunctional but viable segments per patient. Also, the number of patients with a substantial amount of dysfunctional but viable myocardium (>or=4 viable segments) was comparable between the groups with and without diabetes mellitus. The presence of substantial viability on (18)F-FDG SPECT was predictive of improvement in LVEF and heart failure symptoms postoperatively (sensitivity and specificity of 82% and 89%, respectively, in patients with diabetes and 83% and 93%, respectively, in patients without diabetes; not statistically significant). CONCLUSION: (18)F-FDG SPECT is practical for routine assessment of myocardial viability in patients with ischemic LV dysfunction with or without diabetes mellitus. Patients with substantial myocardial viability on (18)F-FDG SPECT have a high probability of improvement of LV function and symptoms after coronary revascularization, irrespective of the absence or presence of diabetes mellitus.     

Anatomical and morphological factors correlating with rupture of intracranial aneurysms in patients referred for endovascular treatment

The size of intracranial aneurysms is the only characteristic shown to correlate with their rupture. However, the critical size for rupture has varied considerably among previous accounts and remains a point of controversy. Our goal was to identify statistically significant clinical and morphological factors predictive of the occurrence of rupture and aneurysm size in patients referred for endovascular treatment. We retrospectively recorded the following factors from 74 patients who presented with ruptured (40) or unruptured (34) aneurysms: aneurysm morphology (uni/multilobulated), location (anterior/posterior), maximum diameter, diameter of the neck, and the patient's age and sex. We performed stepwise discriminant, and stepwise and logistic regression analysis to identify factors predicting rupture and the size of the aneurysm at rupture. The mean diameter of the ruptured aneurysms was 11.9 ± 6.3 mm, range 3.0–33.0 mm, and that of the unruptured aneurysm 13.5 ± 5.8 mm, range 5.0–30 mm. Stepwise discriminant analysis identified aneurysm morphology (P < 0.001) and location in the intracranial circulation (P < 0.001) as statistically significant factors in predicting rupture. Stepwise regression analysis revealed that aneurysm morphology and the size of the neck were predictors of aneurysm size at rupture. Received: 30 December 1997 Accepted: 28 April 1998     

BMIPP imaging to improve the value of sestamibi scintigraphy for predicting functional outcome in severe chronic ischemic left ventricular dysfunction.

Mismatching between beta-methyl-p-iodophenyl-pentadecanoic acid (BMIPP) and perfusion accurately predicts functional outcome after acute myocardial infarction. The current investigation was aimed at evaluating the value of this method to predict the evolution of global function according to the applied treatment in patients with chronic ischemic heart disease. METHODS: Twenty patients with infarction and chronic left ventricular dysfunction were studied (median infarction age 12 wk, range 2 wk-15 y). Radionuclide angiography, two-dimensional echocardiography and BMIPP and gated sestamibi scintigraphy were performed with the patient at rest before and >6 mo after treatment (revascularization in 13 patients and conservative therapy in 7 patients). In 7 patients, radionuclide angiography was repeated after 1 y. RESULTS: On a patient basis, mismatching with BMIPP less than sestamibi was noted in 15 patients at baseline. Of these 15 patients, 11 had significant functional improvement at follow-up versus only 1 of the 5 patients with a matched decreased uptake. Hence, the combined sestamibi/BMIPP was 73% positive and 80% negative in predicting functional outcome, with a global accuracy of 75%. On a segmental basis, using an optimal threshold of uptake defined by receiver operating characteristic curve analysis, sestamibi was only 63% accurate in predicting regional outcome. Adding BMIPP improved the accuracy to 80% (P = 0.001). At follow-up, significant mismatching was still noted in 7 patients in the revascularized group and 1 in the medically treated group. The mismatch was associated with a further increase in ejection fraction at 1-y follow-up in only the revascularized group. CONCLUSION: In patients with chronic left ventricular dysfunction after infarction, a mismatching with BMIPP less than sestamibi reliably identifies jeopardized but viable myocardium and predicts functional recovery with an accuracy similar to that reported in the acute and subacute phases of the infarction.