Colonic responses to gas loads in subgroups of patients with abdominal bloating

OBJECTIVES

We sought to evaluate colonic gas accommodation, ileocecal competence, and colonic clearance in subgroups patients with abdominal bloating.

METHODS

Thirty-six patients complaining of abdominal bloating (12 constipation-predominant irritable bowel syndrome (IBS-C), 12 diarrhea-predominant irritable bowel syndrome (IBS-D), and 12 functional bloating) and 18 healthy controls were studied. Abdominal perception and girth were measured during: (i) 1 h continuous infusion of gas at 24 ml/min into the rectum (accommodation period) and (ii) 30 min free rectal gas evacuation (clearance period). In eight patients and eight healthy subjects, the gas infused was labeled with radioactive xenon (74 MBq (133)Xe), and gas distribution was determined by scintigraphy.

RESULTS

Colonic gas accommodation produced significantly more abdominal symptoms and distension in patients than in healthy subjects (3.8+/-0.2 vs. 2.4+/-0.3 perception score; P<0.001; 10.9+/-0.6 vs. 8.3+/-0.5 mm girth increment; P=0.009). Scintigraphy showed no differences in colonic gas distribution and no ileal gas reflux, but patients exhibited impaired gas clearance from the proximal colon (63%+/-10% clearance in 30 min vs. 80%+/-2% in health; P=0.042), resulting in more residual gas (506+/-46 vs. 174+/-47 ml; P<0.001), perception (1.9+/-0.2 vs. 1.0+/-0.2 score; P=0.015), and girth increment (4.2+/-0.7 vs. 2.2+/-0.5 mm; P=0.024); IBS-C patients exhibited increased sensation and objective distension, as opposed to sensation only in IBS-D and distension only in functional bloating.

CONCLUSIONS

Patients with abdominal bloating have normal colonic accommodation and ileocecal competence but impaired gas clearance from the proximal colon after retrograde infusion, and the consequences of this dysfunction are related to bowel habit.

Effect of clinical variables on the correlation between amount of ST elevation and myocardial scintigraphic perfusion defect during coronary occlusion

PURPOSE

We investigated if the correlation between the amount of ST elevation (STE) and myocardial ischemia could be altered by variables such as hypertension or body mass index (BMI).

METHODS

A 12-lead electrocardiogram and a technetium-99m tetrofosmin injection were performed during balloon coronary occlusion in 34 patients with single-vessel disease.

RESULTS

The sum of STE correlated with scintigraphic extent of ischemia (r = 0.441; P = .009), but this correlation improved significantly in men and patients with BMI of 28 kg/m2 or less and was highest in nonhypertensive patients (r = 0.763; P < .001). In contrast, it was poor in women and patients with BMI greater than 28 kg/m2 or arterial hypertension, being lowest in the latter subset (r = 0.110; P = .664). Moreover, 8 (80%) of 10 patients with extensive hypoperfusion but with low SigmaSTE (< or =20 mm) were hypertensive.

CONCLUSIONS

If confirmed by larger studies, electrocardiographic underestimation of transmural ischemia during coronary occlusion in patients with hypertension or increased BMI may lead to adjustments in STE criteria for reperfusion therapy.

Impaired viscerosomatic reflexes and abdominal-wall dystony associated with bloating

BACKGROUND & AIMS

Abdominal bloating is a frequent complaint in irritable bowel syndrome (IBS), but its underlying mechanism remains uncertain. Our aim was to determine whether the abdominal wall, specifically its adaptation to intra-abdominal volumes, plays a role.

METHODS

In 12 patients complaining of abdominal bloating (8 IBS and 4 functional bloating) and in 12 healthy controls, the effect of colonic gas load (24 mL/min rectal gas infusion for 1 hour) on perception (measured by a 0-6 scale), abdominal girth, and muscular activity was tested. With the participants sitting on an ergonomic chair and the trunk erect, multichannel electromyography was measured via bipolar surface electrodes located over the upper and lower rectus abdominis, and the external and internal oblique bilaterally.

RESULTS

In healthy controls, colonic gas loads produced subjective symptoms (score, 3.0 +/- 0.3), objective abdominal distention (girth increment, 6 +/- 1 mm), and increased the activity of the abdominal muscles (external oblique activity, 11% +/- 3% in; P < .05 vs basal). At the same infused gas volumes, the patients developed significantly more symptoms (score, 4.5 +/- 0.4) and abdominal distention (11 +/- 1 mm; P < .05 vs healthy for both). These abnormal responses were associated with failed tonic contraction of the abdominal wall (external oblique activity change, -1% +/- 4%; P value not significant vs basal) and paradoxic relaxation of the internal oblique (activity reduction, 26% +/- 7%; P < .01 vs basal).

CONCLUSIONS

In patients with bloating, abdominal perception and distention in response to intra-abdominal volume increments are exaggerated markedly and associated with muscular dystony of the abdominal wall.

Relation of myocardial perfusion defects and nonsignificant coronary lesions by angiography with insights from intravascular ultrasound and coronary pressure measurements

Several studies have demonstrated a correlation between myocardial ischemia and severity of coronary lesions as determined by intravascular ultrasound (IVUS) and fractional flow reserve (FFR) measurements. However, their value for the assessment of mild coronary stenoses that are associated with myocardial perfusion abnormalities has not been well studied. The objective of this study was to prospectively compare the results of myocardial perfusion as determined by exercise/dipyridamole myocardial single-photon emission computed tomography with IVUS and FFR measurements in patients who had angiographically mild coronary stenosis (< 50% diameter stenosis by quantitative coronary angiography). Forty-eight patients who had stable coronary disease (61 +/- 11 years of age; 6 women) were included. All had mild coronary stenosis in the proximal/middle segment of > or = 1 coronary artery and had undergone maximal exercise myocardial technetium-99m tetrofosmin single-photon emission computed tomography within 48 hours before coronary angiography. IVUS measurements included lesion lumen area, external elastic membrane area, lesion plaque burden (calculated as external elastic membrane minus lumen area, divided by external elastic membrane, and multiplied by 100), and lumen area stenosis (calculated as reference lumen area minus lesion lumen area, divided by reference lumen area, multiplied by 100). Fifty-three coronary lesions were studied, with a mean percent diameter stenosis of 34.9 +/- 7.9% on angiography. Myocardial perfusion defects were demonstrated by single-photon emission computed tomography in 11 patients (12 myocardial regions) with no differences in lesion percent diameter stenosis compared with those without perfusion defects. The presence of reversible perfusion defects was associated with a higher lesion plaque burden as evaluated by IVUS (67.4 +/- 8.1% vs 60.2 +/- 9.3%, p = 0.01). FFR values did not differ in the presence or absence of perfusion defects (0.90 +/- 0.06 vs 0.92 +/- 0.07, respectively; p = NS). In conclusion, plaque burden as determined by IVUS may partly explain the presence of myocardial perfusion defects in cases of angiographically nonsignificant coronary lesions. However, the high FFR values associated with these lesions suggest that other mechanisms, such as endothelial/microvascular dysfunction, might also account for perfusion abnormalities in these patients.

Do myocardial perfusion SPECT and radionuclide angiography studies in adult patients with hypertrophic cardiomyopathy have prognostic implications?

BACKGROUND

Some myocardial perfusion single photon emission computed tomography (SPECT) and radionuclide ventriculography studies have suggested that the presence of regional perfusion defects and diastolic abnormalities could have prognostic implications in patients with hypertrophic cardiomyopathy (HC). The aim of this prospective study was to analyze the prognostic value of these techniques in adult patients with HC.

METHODS AND RESULTS

One hundred one patients with HC (44 women; mean age, 54 +/- 16 years; 55% obstructive) were prospectively studied by means of myocardial perfusion SPECT and radionuclide angiography. Of these patients, 55 (54.4%) had an abnormal myocardial perfusion SPECT study: 28 (27.7%) had fixed defects and 41 (40.6%) had reversible defects; 15 (14.8%) of these patients had both types of defect. Of the patients, 16% had left ventricular ejection fraction lower than 60%, 25.7% had an abnormal peak filling rate, and 51% had an abnormal time to peak filling rate. During 5.6 +/- 2.7 years of follow-up, 13 patients (12.8%) died (heart failure 8 and sudden death in 5) and 14 had one or more severe complications develop (syncope in 6, angina III-IV in 4, dyspnea III-IV in 10, and acute myocardial infarction in 3). The summed difference score was higher in patients with cardiac death (2.2 +/- 2.3 vs 1.1 +/- 1.3, P = .008), and fixed defects were more prevalent in patients with severe complications (57% vs 21%, P = .01). In the Kaplan-Meier survival plot analysis, severe complications were more likely in patients with fixed defects (P = .01) or ejection fraction lower than 60% ( P = .01).

CONCLUSIONS

Prognostic information from myocardial perfusion SPECT and radionuclide angiography has limited clinical significance with regard to cardiac death in adult patients with HC. However, the presence of fixed defects and lower ejection fraction in these patients has an adverse prognostic meaning for severe complications.

Intestinal gas distribution determines abdominal symptoms

BACKGROUND

Patients with functional gut disorders manifest poor tolerance to intestinal gas loads but the mechanism of this dysfunction is unknown.

AIM

Our aims were firstly, to explore the relative importance of the amount of intestinal gas versus its distribution on symptom production, and secondly, to correlate gut motility and perception of gas loads.

SUBJECTS

Fourteen healthy subjects with no gastrointestinal symptoms.

METHODS

In each subject a gas mixture was infused (12 ml/min) either into the jejunum or rectum for one hour during blocked rectal gas outflow, and subsequently gas clearance was measured over one hour of free rectal evacuation. We measured abdominal perception, distension, and gut tone by duodenal and rectal barostats.

RESULTS

Similar magnitude of gas retention (720 ml) produced significantly more abdominal symptoms with jejunal compared with rectal infusion (perception score 4.4 (0.4) v 1.5 (0.5), respectively; p<0.01) whereas abdominal distension was similar (15 (2) mm and 14 (1) mm girth increment, respectively). Jejunal gas loads were associated with proximal contraction (by 57 (5)%) and colonic loads with distal relaxation (by 99 (20)%).

CONCLUSION

The volume of gas within the gut determines abdominal distension whereas symptom perception depends on intraluminal gas distribution and possibly also on the gut motor response to gas loads.

Nebulized amphotericin B concentration and distribution in the respiratory tract of lung-transplanted patients

BACKGROUND

A criticism of using nebulized amphotericin B (nAB) as prophylaxis against Aspergillus infection after lung transplantation is the lack of knowledge of its pharmacokinetics and distribution in the lung. The aim of this study was to ascertain the concentrations and distribution of nAB in the respiratory tract of patients receiving lung transplantations.

METHODS

In the drug-concentration study, 120 bronchoscopies were performed in 39 patients receiving lung transplantions after administration of 6 mg of nAB once daily for a minimum of 7 days. Mean nAB concentration in bronchial aspirated secretions (BAS) and bronchoalveolar lavage (BAL) was determined at 4, 12, 24, and 48 hours postnebulization. In the distribution study, 17 patients inhaled 6 mg of 99m technetium-labeled AB, and pulmonary distribution was measured using a gamma camera. Pulmonary perfusion was also measured. Both tests were quantitatively evaluated.

RESULTS

In the drug-concentration study, mean concentrations of 1.46 microg/mL in BAS and 15.75 microg/mL in BAL were reached at 4 hours. At 24 hours, concentrations were 0.37 microg/m and 11.02 microg/mL in BAS and BAL, respectively. In the distribution study, 99m technetium-labeled AB distribution was uniform in 12 of 13 allografts without bronchiolitis obliterans syndrome (BOS) and in 1 of 4 allografts with BOS. A close correlation was observed between regional drug distribution and regional perfusion (r=0.82, P<0.01).

CONCLUSIONS

nAB concentrations remained high for the first 24 hours in BAL and for less time in BAS, with distribution of the drug being uniform in patients without BOS. Furthermore, lung-perfusion studies appear to be useful to ascertain nAB distribution in patients receiving lung transplantions.

[Exercise-induced left bundle-branch block in patients with coronary artery disease versus patients with normal coronary arteries]

INTRODUCTION AND OBJECTIVES

Exercise-induced left bundle-branch block does not always denote the presence of underlying coronary artery disease. The aim of this study was to analyze the clinical characteristics and evolution of patients with rate-dependent left bundle-branch block.

PATIENTS AND METHOD

9,318 consecutive exercise stress studies were reviewed. The clinical characteristics and evolution (mean follow-up: 6.9 years) of 20 patients with exercise-induced left bundle-branch block in which coronary angiography had been performed were analyzed.

RESULTS

Eight out of 20 patients had normal coronary arteries (group A) and 12 had coronary artery disease (group B). Peak O2 consumption, peak myocardial O2 consumption, and heart rate when block appeared (132 20 vs. 95.4 23 beats/min; p = 0.002) were significantly higher in group A. Seven of the 8 patients with normal coronary arteries had chest pain coinciding with the first beat of left bundle-branch block. There were no deaths during follow-up in group A, but permanent left bundle-branch block appeared in 5 patients of this group who experienced disappearance of exercise-related pain. There were 3 deaths in group B and 2 patients had acute myocardial infarction during follow-up. One patient in each group developed atrioventricular block and required pacemaker implantation.

CONCLUSIONS

In contrast with patients with left bundle-branch block and coronary artery disease, the prognosis of patients with painful left bundle-branch block and normal coronary arteries is good. However, the development of permanent left bundle-branch block is frequent. Atrioventricular block, although rare, may occur.

[Exercise-induced left bundle-branch block in patients with coronary artery disease versus patients with normal coronary arteries]

INTRODUCTION AND OBJECTIVES

Exercise-induced left bundle-branch block does not always denote the presence of underlying coronary artery disease. The aim of this study was to analyze the clinical characteristics and evolution of patients with rate-dependent left bundle-branch block.

PATIENTS AND METHOD

9,318 consecutive exercise stress studies were reviewed. The clinical characteristics and evolution (mean follow-up: 6.9 years) of 20 patients with exercise-induced left bundle-branch block in which coronary angiography had been performed were analyzed.

RESULTS

Eight out of 20 patients had normal coronary arteries (group A) and 12 had coronary artery disease (group B). Peak O2 consumption, peak myocardial O2 consumption, and heart rate when block appeared (132 20 vs. 95.4 23 beats/min; p = 0.002) were significantly higher in group A. Seven of the 8 patients with normal coronary arteries had chest pain coinciding with the first beat of left bundle-branch block. There were no deaths during follow-up in group A, but permanent left bundle-branch block appeared in 5 patients of this group who experienced disappearance of exercise-related pain. There were 3 deaths in group B and 2 patients had acute myocardial infarction during follow-up. One patient in each group developed atrioventricular block and required pacemaker implantation.

CONCLUSIONS

In contrast with patients with left bundle-branch block and coronary artery disease, the prognosis of patients with painful left bundle-branch block and normal coronary arteries is good. However, the development of permanent left bundle-branch block is frequent. Atrioventricular block, although rare, may occur.

[Unified three-dimensional images of myocardial perfusion and coronary angiography]

INTRODUCTION AND OBJECTIVES

In everyday clinical practice, the cardiologist needs to integrate anatomical and functional information from patients with coronary artery disease. The aim of this study is to present a way to unify, in three-dimensional images, anatomical information from coronary angiography with physiological information from myocardial perfusion scintigraphy.

METHODS

Three patients with one vessel disease (left anterior descending, right coronary and left circumflex arteries, respectively) scheduled for percutaneous coronary revascularization were selected. Two-dimensional angiographic images were obtained before and after revascularization. 99mTc-tetrofosmin was administered during coronary occlusion and tomographic images corresponding to the occlusion were detected after coronary dilatation. Control rest scintigraphic images were obtained after two days. The three-dimensional coronary tree from coronary angiography was superposed on the epicardial contours of the myocardial perfusion images following a method of our own.

RESULTS

A correct three-dimensional reconstruction of myocardial contour and coronary tree was achieved for each patient. The three-dimensional unified images showed excellent concordance between the extent of perfusion defects and the anatomic distribution of the occluded vessel.

CONCLUSIONS

Three-dimensional unification of myocardial perfusion images and coronary angiography is technically possible. This technology integrates anatomical and functional information to facilitate the cardiologist's decision-making and so improve coronary patient management.

[Myocardial perfusion SPECT and isotopic ventriculography in obstructive and non-obstructive hypertrophic myocardiopathy]

OBJECTIVE

To evaluate the role of myocardial perfusion SPET and radionuclide ventriculography in patients with hypertrophic cardiomyopathy (HC).

METHODS

Exercise myocardial perfusion SPET with 99mTc-tetrofosmin and radionuclide ventriculography were performed in a consecutive series of 101 patients (54 15 years, 50 women, 55 with dynamic obstruction) diagnosed of HC by echo. Follow-up from the diagnosis was 9,9 6,7 years (1 to 28 years).

RESULTS

Thirty six percent of patients had perfusion defects (non reversible in 15 and reversible in 21). In non obstructive HC higher number of patients with non reversible defects (p = 0.01 was obseved and in patients with no reversible defects higher incidence of pathologic Q waves in ECG (p = 0.01), Higher ventricular volumes (p < 0.05), lower ejection fraction (p = 0,0001) and longer time to peak emptying velocity (p < 0.05). There were 4 cardiac deaths, 15 syncopes, 18 pacemakers and 6 myectomy. Ejection fraction was higher in patients with syncope (p = 0,034) and there was no isotopic variable predictive of mortality, pacemaker or myectomy.

CONCLUSIONS

Neither SPET nor radionuclide ventriculography have a prognostic role in patients with HC, but patients with syncope have higher values of ejection fraction. Patients with non reversible defects have higher rate of pathologic Q waves in ECG, higher ventricular volumes and lower ejection fraction. This is indicative of evolution to dilated form of HC.

[Prognostic value of cardiac perfusion scintigraphy associated with the dobutamine test in acute coronary syndromes]

OBJECTIVES

This study aimed to establish the value of myocardial ischemia induced by the dobutamine infusion test associated to 99m technetium isonitrile single photon emission computed tomography in patients with unstable angina or non Q-wave infarction during the first days in the Coronary Care Unit.

METHODS

Fifty three patients with unstable coronary syndromes and common medical treatment were studied with a moderate-dose dobutamine test (5 to 20 microgram/Kg/min) using a 99mTc-MIBI SPECT. The results were correlated with the incidence of recurrent angina, infarction, death or revascularization.

RESULTS

The dobutamine test induced a reversible perfusion defect in 36 patients (68%) and angina in 12 of them (12/36, 33%). However, the patients who had a positive test had a similar incidence of events as those with a negative test (58% vs 59%). Thus, while the sensitivity of the dobutamine test to identify patients at risk was relatively high (68%), its specificity (32%) and its negative predictive value (41%) were low. The patients with dobutamine-induced angina, however, had a higher scintigraphy score (3.0 +/- 1,7 vs 1.6 +/- 1.8, p < 0.02) and a higher incidence of recurrent angina (8/12, 67% vs 13/41, 31%, p < 0.04) than those without, at a comparable double product.

CONCLUSIONS

In conventionally treated patients with unstable coronary syndromes, the specificity of the inducible scintigraphic ischemia with moderate dose of dobutamine performed during the first days is too low to be used as a marker for in-hospital events. However, inducible angina with dobutamine suggests an extensive jeopardized area and/or a particularly reduced ischemic threshold.

[Tomographic studies of myocardial perfusion normality with 99m Tc-Tetrofosmin. Spanish multicenter study]

As a first phase in a nationwide multicenter study to obtain myocardial perfusion normality patterns, this work presents the study design and quality control methodology used to guarantee that the gammacameras fulfilled some minimum quality requirements. The following aspects were considered in the study design in order to guarantee the homogeneity and interchangeability of the results: creation and structure of the work group, data interchange system, data selection and acquisition, centralized archiving and processing, assessment system, study acceptance criteria and distribution of the results. To carry out the instrumental quality control, three phantom studies were established, one to control the rotation center, another to verify tomographic uniformity and a third to simulate the shape and orientation of the left ventricle. The three phantoms circulated through all of the 18 participating centers in this project, which corresponded to 19 gammacameras. Very strict guidelines had to be followed in the acquisition and processing of these phantom studies. If any camera and/or center did not fulfill the criteria established, it was advised of the problem detected in order to correct it. Once the defect was repaired, all the phantoms were sent again for verification. Uniformity of the rotation center was quantified by means of the eccentricity of a 360 degrees orbit, admitting up to a maximum of 10%. Tomographic uniformity was visually assessed, taking in account the number of slices with rings and their contrast and finally no artifacts could be present in the reconstructed study of the ventricle. The center of rotation was within limits in all the cameras except one case while the tomographic uniformity was incorrect in 6 cases. All the departments, except one, corrected the defects detected, and passed the acceptance test. The results made it possible to guarantee adequate homogeneity and instrumental quality in this multicenter study.

[Tomographic studies of myocardial perfusion normality with 99m Tc-Tetrofosmin. Spanish multicenter study]

This objective of this study was to obtain a pool of Myocardial Perfusion SPECTs with a 99mTetrofosmin stress/rest one day protocol in normal volunteers having a less than or equal to 5% likelihood of coronary artery disease that represents normalcy in the Spanish population. A total of 169 volunteers from 15 hospitals were studied. The volunteers were divided into 5 groups: Groups 1, 2 or 3 corresponding to men < 30 years (n = 33), men between 30 and 50 years (n = 32), or men > 50 years (n = 31); Groups 4 or 5: premenopausal (n = 38) or postmenopausal women (n = 35). A clinical history, physical examination, clinical laboratory parameters, echocardiography and a symptom limited exercise stress test were performed in all of them and had to be normal. The mean likelihood of coronary artery disease was 1.15 +/- 1.07%.Twenty-four segments were analyzed in each study and were classified into 5 grades of uptake (1 = normal, 2, 3, 4 = mild, moderate or severe defect and 5 = no uptake). Defects were then analyzed according to sex and location. Considering the stress and rest studies separately (8,112 segments), only 19 moderate and 75 mild defects were found, these corresponding to 16 volunteers, with more inferior defects in men and anterior defects in women. These data validate the normalcy of our population. A pool of Myocardial Perfusion SPECTs with a 99mTetrofosmin stress/rest one day protocol in normal volunteers that represents Spanish normal values was obtained.

Prognostic assessment of uncomplicated first myocardial infarction by exercise echocardiography and Tc-99m tetrofosmin gated SPECT

BACKGROUND

We evaluate the prognostic value of stress echo and gated single photon emission computed tomography (SPECT) after a first uncomplicated acute myocardial infarction.

METHODS AND RESULTS

We used predischarge maximal subjective exercise echocardiography and gated SPECT with technetium 99m tetrofosmin to prospectively study 103 patients younger than 70 years with a first acute myocardial infarction. During a 12-month follow-up period, 2 patients died, 9 had heart failure, and 29 had ischemic complications (4 reinfarction and 25 angina). Predictive variables for heart failure in multivariate analysis were ejection fraction evaluated by echocardiography (odds ratio [OR] 8.5, P =.016) or by gated SPECT (OR 10.7, P =.009). Predictive variables for ischemic complications in multivariate analysis were less than 5 metabolic equivalents (METS) in exercise test (OR 5.2, P =.007) and greater than 15% ischemic extent in the polar map (OR 3.6, P =.04) of SPECT.

CONCLUSIONS

Exercise echocardiography and Tc-99m tetrofosmin gated SPECT were predictive for heart failure, but exercise SPECT was the only test with predictive power for ischemic complications.

[Significance of segmentary reversal defects in the myocardial SPECT with 99mTC-tetrofosmin myocardial SPECT]

OBJECTIVES

To evaluate segmentary reverse defects (RD) (uptake higher in exercise than in rest) in 99mTc-tetrofosmin SPECT.

METHODS AND RESULTS

1,124 consecutive SPECT studies were reviewed and 80 (7%) segmentary RD were identified. Thirty-eight patients with RD attributed to artifact (extra cardiac uptake) were excluded. Thus, 42 patients (3.6%), 21 with and 21 without previous infarct, were studied. Thirteen out of 21 RD in patients without previous infarct corresponded to inferior region and 8 to the anterior region. In three out of 8 patients in whom the coronary angiography was performed, the coronary arteries were angiographically normal and 5 had stenosis of between 50% to 70% of coronary arteries corresponding to RD. Of the 21 RD in patients with previous infarct, the RD site corresponded to the same region of the necrosis (15 inferior and 6 anterior). All had viability criteria (uptake higher than 40% in more than 50% of the region) in rest uptake SPECT quantification. In nine out of 11 patients in whom a coronary angiography was carried out, patency of the artery responsible for the infarct was verified.

CONCLUSIONS

3.6% of segmentary RD, which were not attributed to the artifact, were observed in myocardial perfusion 99mTc-tetrofosmin SPECT studies. Half of these cases corresponded to regions without previous infarct and with normal coronary arteries or non-severe coronary stenosis. The remaining corresponded to regions with previous infarct and with viability criteria.

[Quantification of left-to-right shunt in atrial septal defect using oximetry, isotopes, and Doppler echocardiography. Is there a method of reference?]

INTRODUCTION

Determination of pulmonary to systemic blood flow ratio (QP/QS) is considered to be important for the management of patients with atrial septal defect. The QP/QS provides information on shunt severity and is usually determined by three methods: oximetry, first-pass radionuclide angiocardiography and Doppler echocardiography. The aim of the present study was to assess the accuracy and concordance level of these three methods in QP/QS quantification in atrial septal defects.

PATIENTS AND METHODS

Sixty-four adult atrial septal defects patients in whom QP/QS was determined by these three methods with a 6 month interval were studied. Nuclear and echocardiographic post-surgical studies were repeated in 36 patients.

RESULTS

QP/QS values determined by the three techniques had a low correlation between them: oximetry (r = 0.52; SEE = 0.74); radionuclide angiocardiography (r = 0.40; SEE = 0.79) and Doppler echocardiography (r = 0.72; SEE = 0.57). Radionuclide angiocardiography underestimated QP/QS > 3 (-0.61 +/- 1.21; p < 0.01). Only in 33% of studies there concordance (differences < 0.5) among the three methods and in 58% between two methods. Right ventricular dilatation and tricuspid regurgitation influenced radionuclide accuracy. Nevertheless, the correlation between this technique and echocardiography was satisfactory when the 36 post-surgical were included (r = 0.75); both techniques agreed in the diagnosis of the two cases with residual post-surgical shunt.

CONCLUSIONS

Inter-method disparity in QP/QS quantification is high and no method can be used as a gold standard; clinical decisions therefore based on QP/QS quantification by one technique alone are ill-advised.

[Prognosis of patients with angina pectoris or silent ischemia: exercise 99mTC-MIBI SPECT]

INTRODUCTION AND OBJECTIVES

Although different reports have compared the extent of the myocardial ischemia in patients with or without angina during exercise test, there have been few publications which have studied their prognosis. The aim of this study is to analyze the prognostic value of the presence of angina during 99mTc-MIBI SPECT in patients with proven coronary artery disease without previous myocardial infarction.

PATIENTS AND METHODS

We studied 82 patients prospectively with at least one coronary stenosis > 70% and with reversible perfusion defects in 99mTc-MIBI SPECT (long protocol). Twenty two of these patients had angina during exercise test. The extension of ischemia was quantified on SPECT and the severity of coronary stenoses on coronary angiography. The mean follow-up period was 3.2 years.

RESULTS

The angina patients showed a significantly lower coronary reserve (exercise duration: 6.3 min vs 8 min; p = 0.03), a lower maximal O2 consumption (5.8 METs vs 6.2 METs; p = 0.04), a higher rate of ST depression > 1 mm (64% vs 19%; p = 0.006) and a higher degree of ST depression (0.9 mm vs 0.4 mm; p = 0.01) than those patients without angina. There were no significant differences in the extent of ischemia in SPECT or in the angiographic severity of coronary disease between either groups. During the follow-up period the presence of severe complications (myocardial infarction or death) tended to be higher (27% vs 17%; NS) in patients with angina and the indication of surgical revascularization was also significantly higher (50% vs 17%; p = 0.002) in this group.

CONCLUSIONS

Presence of angina during 99mTc-MIBI SPECT portends a higher risk of medium and long term complications, mainly due to surgical revascularization.

Comparison of patients with anterior wall healed myocardial infarction with and without exercise-induced ST-segment elevation

To assess the extent of myocardial necrosis and ischemia in patients with anterior wall healed myocardial infarction depending on whether ST-segment elevation was present on precordial leads during exercise testing, 62 consecutive patients (49 men and 13 women, age [mean +/- SD] 56 +/- 11 years) with anterior wall infarcts were assessed with exercise technetium-99m (Tc-99m) methoxy-isobutyl-isonitrile single-photon emission computed tomography and quantification of the extent of necrosis and ischemia on polar maps: 22 patients had > or = 1 mm ST-segment elevation during exercise, and 40 did not. The extent of the necrosis in the anteroseptal (p = 0.001) and apical (p = 0.002) regions, the extent of ischemia in the lateral region (p = 0.003) on polar maps, and the frequency of ventricular aneurysm as shown by cardiac catheterization (p = 0.001) were significantly greater in patients with ST-segment elevation. In a multiple logistic regression model, both extent of necrosis in the anteroseptal region (odds ratio 10.8; 95% confidence interval 2.7 to 44.0) and extent of ischemia in the lateral region (odds ratio 7.25; 95% confidence interval 1.6 to 32.7) were associated with exercise-induced ST-segment elevation. These data suggest that ST-segment elevation in anterior infarctions is associated with wider necrosis in the anteroseptal and apical regions, with a wider extent of ischemia in the lateral region and a higher frequency of ventricular aneurysm. Consequently, it cannot be used as a marker of viability.

Myocardial necrosis by electrocution: evaluation of noninvasive methods

We present the case of a young man who suffered severe anteroapical myocardial necrosis caused by electrocution. In addition to the enzymatic and electrocardiographic changes suggesting necrosis, a clear positive segmental image on 99mTc-pyrophosphate scintigraphy and a defect on a 201Tl SPECT scan at rest were also found. Although these tests were indicative of extensive anteroapical transmural myocardial necrosis, the echocardiographic study only revealed mild anteroapical hypokinesia.

[Myocardial contractility and viability. A radionuclide tomography study using technetium-99m labeled isonitriles]

BACKGROUND

There are comparatively few studies evaluating the patterns of myocardial viability and its relation with contractility in patients with coronary artery disease. The aim of the present study was to quantify the viable and nonviable myocardium, using 99m-technetium isonitriles SPET, as related with left ventricular regional wall motion abnormalities.

METHOD

61 consecutive patients with coronary artery disease were investigated. The severity and extension of the defects were evaluated using a qualitative and quantitative analysis of the 99mTc-isonitriles SPET and compared with ventricular wall motion in contrast ventriculography. An uptake level of 40% of peak uptake or higher was considered as indicating viable myocardium.

RESULTS

Of the 244 evaluated regions (4 per patient), 72 (29%) had normal perfusion, 100 (41%) were ischemic, 25 (10%) had a mild irreversible defect and 47 (19%) had a severe irreversible defect. Wall motion was normal in 176 regions (72%), 29 (12%) were hypokinetic, and 39 (16%) were akinetic of dyskinetic. The amount of viable myocardium in akinetic and dyskinetic regions (64.8%) was significantly different (p < 0.05) from that in hypokinetic (86.1%) and normokinetic (98.8%) regions. Visual assessment of uptake underestimated myocardial viability, as quantitative analysis disclosed that in 61% of akinetic and dyskinetic regions with severe irreversible defects there was more than 50% of viable myocardium.

CONCLUSIONS

In 61% of akinetic and dyskinetic regions with a severe irreversible defect in perfusion scintigraphy positive viability criteria were found. Therefore, visual assessment of the myocardial perfusion studies using 99mTc-MIBI SPET underestimates viable myocardium. Tomographic studies with quantification of the uptake and defect extension are required for a proper evaluation of viable myocardium.

[Subtraction scintigraphy with thallium-201 chloride and technetium-99m pertechnetate versus high resolution ultrasonography in the localization of the parathyroid glands in primary hyperparathyroidism]

BACKGROUND

The aim of this study was to evaluate the use of scintigraphy with thallium-201 chloride (201 Tl) and technetium-99m pertechnetate (99mTc) in the diagnosis of the localization of the pathological parathyroid glands in primary hyperparathyroidism and compare the results with those of high resolution ultrasonography.

METHODS

Twelve patients of 56.1 +/- 7.8 years of age diagnosed with primary hyperparathyroidism were studied between March 1987 and June 1990. High resolution ultrasonography with a 7.5 MHz transducer and scintigraphy of digital subtraction with 201Tl-99mTc were carried out preoperatively in all the patients. None of the patients had had previous cervical surgery and diagnosis was proven following surgery by histopathologic study.

RESULTS

Ultrasonography detected 9 out of 11 adenomas and 3 out of 4 hyperplastic glands. Scintigraphy identified 9 adenomas and only 2 of the hyperplastic glands. With this latter technique there was one false positive. The sensitivity of ultrasonography was 80% and that of scintigraphy was 73% with specificity being 100% vs 96.9%, respectively.

CONCLUSIONS

Subtraction 201 Tl-99mTc scintigraphy is useful in the diagnosis of the localization of pathologic parathyroid glands in patients with no previous cervical surgery although in this series this technique did not surpass that of high resolution ultrasonography.

[Renal transplantation in children: punction-aspiration biopsy and renogram with 99mTc-DTPA]

BACKGROUND

Renal transplantation in children raises numerous diagnostic problems. The renography obtained with diethyltriaminopentaacetic acid marked with (99mTc metastable technetium (99mTc-DTPA) was compared with fine needle aspiration biopsy (FNAB) in search of a better interpretation of post-transplant crisis: rejection, acute tubular necrosis, toxicity by cyclosporin A and infection.

METHODS

Sixteen acute post-transplant episodes were studied in 13 children submitted to renal transplantation. The post-transplant time was 6 days to 2.5 years. The basal renography and FNAB were carried out following the initial clinical manifestations and over a period of less than one week. The vascular and renographic phases were evaluated by interpreting the renography and were compared to previous renographies. The diagnosis of the aspiration biopsy was expressed as: normal, acute tubular necrosis, total necrosis, toxicity by cyclosporin A, viral infection and rejection.

RESULTS

Results agreed in 14 out of 16 cases: 1 normal, 3 acute tubular necrosis by renography and cellular necrosis by cytology, 9 rejections and 1 infection (increase in renal transit time). In the 2 cases with total necrosis of 100% followed by loss of renal allograft, the renographic diagnosis was severe vascular rejection with a negative prognosis.

CONCLUSIONS

In this series FNAB confirmed the renography as useful in the early diagnosis of complications which may appear in children undergoing renal transplantation.

Intestinal permeability to 99mTc-diethylenetriaminopentaacetic acid in inflammatory bowel disease

Intestinal permeability in inflammatory bowel disease and its relation to periods of disease activity has been investigated by measuring the urinary excretion of DTPA labeled with 99mTc. Urine excretion in 10 control subjects was 2.7 +/- 1% of the test dose. Twelve patients with ulcerative colitis excreted 5.08 +/- 1.6% in remission, 10.61 +/- 2% during periods of mild activity, 19.41 +/- 0.9% during moderate activity, and 15.41 +/- 6.3% with severe activity. Sixteen patients with Crohn's disease excreted 5.7 +/- 1.9% in remission, 8.47 +/- 2.8% during mild activity of the disease, and 14.29 +/- 5.8% during moderate activity. No differences were observed between ulcerative colitis and Crohn's disease, or between ileal and colonic forms of Crohn's disease. Excretion in remission was significantly greater than in control subjects and there was a correlation between excretion and disease activity. In serial determinations done in seven patients we found that urine excretion of the test substance correlated with disease activity. We also studied DTPA excretion in 10 cases with gastric or duodenal ulcer (2.28 +/- 1.4%), six cases of acute gastroenteritis (4.87 +/- 3.1%) and nine cases with other intestinal diseases (3.6 +/- 1.1%). In all these cases, DTPA excretion was lower than in inflammatory bowel disease. Our results show that the urinary excretion of DTPA is a simple test that measures accurately the degree of activity of inflammatory bowel disease. The test is useful in Crohn's disease as well as in ulcerative colitis, and detects intestinal permeability abnormalities even in clinical remission. Significantly lower excretions are found in other intestinal diseases. The test may be recommended as a screening test for use in clinical practice.