Omission of bone scanning according to staging guidelines leads to futile therapy in non-small cell lung cancer

The leading European and American professional societies recommend that bone scans (BS) should be performed in the staging of lung cancer only in those patients with bone pain. This prospective study investigated the sensitivity of conventional skeletal scintigraphy in detecting osseous metastases in patients with lung cancer and addressed the potential consequences of failure to use this method in the work-up of asymptomatic patients. Subsequent to initial diagnosis of non-small cell lung cancer, 100 patients were examined and questioned regarding skeletal complaints. Two specialists in internal medicine decided whether they would recommend a bone scan on the basis of the clinical evaluation. Skeletal scintigraphy was then performed blinded to the findings of history and physical examination. The combined results of magnetic resonance imaging (MRI) of the vertebral column, positron emission tomography (PET) of skeletal bone and the subsequent clinical course served as the gold standard for the identification of osseous metastases. Bone scintigraphy showed an 87% sensitivity in the detection of bone metastases. Failure to perform skeletal scintigraphy in asymptomatic patients reduced the sensitivity of the method, depending on the interpretation of the symptoms, to 19-39%. Without the findings of skeletal scintigraphy and the gold standard methods, 14-22% of patients would have undergone unnecessary surgery or neoadjuvant therapy. On this basis it is concluded that bone scans should not be omitted in asymptomatic patients.

F-18 NaF PET for detection of bone metastases in lung cancer: accuracy, cost-effectiveness, and impact on patient management

As bone metastases might be present in lung cancer despite a normal bone scan, we examined various alternatives prospectively. Positron emission tomography using F-18 sodium fluoride (PET) and single photon emission tomography (SPECT) were more sensitive than a planar bone scan. PET was more accurate with a shorter examination time than SPECT but had higher incremental costs.

INTRODUCTION

Previous studies have shown that vertebral bone metastases not seen on planar bone scans may be present on F-18 fluoride positron emission tomography (PET) scan or single photon emission computed tomography (SPECT). The purpose of this study was to measure the accuracy, clinical value and cost-effectiveness of tomographic bone imaging.

MATERIALS AND METHODS

A total of 103 patients with initial diagnosis of lung cancer was prospectively examined with planar bone scintigraphy (BS), SPECT of the vertebral column and PET using F-18 sodium fluoride (F-18 PET). Receiver operating characteristic (ROC) curve analysis was used for determination of the diagnostic accuracy. A decision-analysis model and the national charge schedule of the German Hospital Association were used for determination of the cost-effectiveness.

RESULTS

Thirteen of 33 patients with bone metastases were false negative on BS, 4 on SPECT, and 2 on F-18 PET. The area under the ROC curve was 0.771 for BS, 0.875 for SPECT, and 0.989 for F-18 PET (p < 0.05). As a result of SPECT and F-18 PET imaging, clinical management was changed in 8 (7.8%) and 10 (9.7%) patients. Compared with BS, the costs per additional correctly diagnosed patient were 1272 Euro with SPECT and 2861 Euro with F-18 PET. The threshold for the costs of F-18 PET being more cost-effective than SPECT was 345 EUR.

CONCLUSION

Routine performance of tomographic bone imaging improves the therapeutic strategy because of detection of otherwise missed metastases. F-18 PET is more effective than SPECT but is associated with higher incremental costs.

Imaging proliferation in lung tumors with PET: 18F-FLT versus 18F-FDG

Recently, the thymidine analog 3'-deoxy-3'-(18)F-fluorothymidine (FLT) was suggested for imaging tumoral proliferation. In this prospective study, we examined whether (18)F-FLT better determines proliferative activity in newly diagnosed lung nodules than does (18)F-FDG.

METHODS

Twenty-six patients with pulmonary nodules on chest CT were examined with PET and the tracers (18)F-FDG and (18)F-FLT. Tumoral uptake was determined by calculation of standardized uptake value (SUV). Within 2 wk, patients underwent resective surgery or had core biopsy. Proliferative activity was estimated by counting nuclei stained with the Ki-67-specific monoclonal antibody MIB-1 per total number of nuclei in representative tissue specimens. The correlation between the percentage of proliferating cells and the SUVs for (18)F-FLT and (18)F-FDG was determined using linear regression analysis.

RESULTS

Eighteen patients had malignant tumors (13 with non-small cell lung cancer [NSCLC], 1 with small cell lung cancer, and 4 with pulmonary metastases from extrapulmonary tumors); 8 had benign lesions. In all visible lesions, mean (18)F-FDG uptake was 4.1 (median, 4.4; SD, 3.0; range, 1.0-10.6), and mean (18)F-FLT uptake was 1.8 (median, 1.2; SD, 2.0; range, 0.8-6.4). Statistical analysis revealed a significantly higher uptake of (18)F-FDG than of (18)F-FLT (Mann-Whitney U test, P < 0.05). (18)F-FLT SUV correlated better with proliferation index (P < 0.0001; r = 0.92) than did (18)F-FDG SUV (P < 0.001; r = 0.59). With the exception of 1 carcinoma in situ, all malignant tumors showed increased (18)F-FDG PET uptake. (18)F-FLT PET was false-negative in the carcinoma in situ, in another NSCLC with a low proliferation index, and in a patient with lung metastases from colorectal cancer. Increased (18)F-FLT uptake was related exclusively to malignant tumors. By contrast, (18)F-FDG PET was false-positive in 4 of 8 patients with benign lesions.

CONCLUSION

(18)F-FLT uptake correlates better with proliferation of lung tumors than does uptake of (18)F-FDG and might be more useful as a selective biomarker for tumor proliferation.

Inhibition of MMP-9 expression by PPARgamma activators in human bronchial epithelial cells

BACKGROUND

The release of matrix degrading enzymes such as matrix metalloproteinase 9 (MMP-9) from bronchial epithelial cells is critically involved in airway wall remodelling in chronic inflammatory processes of the respiratory system. MMP-9 expression is induced by inflammatory mediators such as tumour necrosis factor (TNF)-alpha, but to date nothing is known about the mechanisms of inhibition of MMP-9 expression in these cells.

METHODS

A study was undertaken to examine whether activators of the nuclear transcription factor peroxisome proliferator activated receptor gamma (PPARgamma) might modulate MMP-9 expression in two different bronchial epithelial cell lines.

RESULTS

PPARgamma was expressed and was functionally active in NL20 and BEAS cells. Activation of PPARgamma by rosiglitazone or pioglitazone significantly reduced TNF-alpha and PMA induced MMP-9 gelatinolytic activity in a concentration dependent manner in both cell lines, but did not alter the expression of tissue inhibitor of MMPs type 1 (TIMP-1), the local inhibitor of MMP-9. Northern blot analysis revealed a decrease in MMP-9 mRNA expression following treatment with PPARgamma which resulted from the inhibition of NF-kappaB activation in these cells, as determined by transient transfection assays and electromobility shift assays.

CONCLUSION

Activation of PPARgamma in human bronchial epithelial cells limits the expression of matrix degrading MMP-9. This might have therapeutic applications in chronic inflammatory processes of the respiratory system.

Pulmonary Hemodynamics in Obstructive Sleep Apnea: Frequency and Causes of Pulmonary Hypertension

The association between nocturnal apneas and transient pulmonary hypertension (PHT) has been well documented. However, there is controversy over the frequency and pathophysiological mechanisms of daytime pulmonary hypertension in patients with obstructive sleep apnea (OSAS). The present study sought to evaluate frequency and mechanisms of pulmonary hypertension in patients with OSAS. It included 49 consecutive patients with polysomnographically proven OSAS without pathological lung function testing. All patients performed daytime measurements of pulmonary hemodynamics at rest and during exercise (50-75W). Six patients (12%) had resting PHT mean pulmonary of artery pressure (PAPM) of >20 mmHg), whereas 39 patients (80%) showed PHT during exercise (PAPM >30 mmHg). Multiple regression analysis revealed 3 independent contributing factors for mean pulmonary artery pressure during exercise (PAPMmax): body mass index, age and total lung capacity % of predicted. Twenty-five of the 39 patients with pathologically high PAPMmax (64%) showed elevated pulmonary capillary wedge pressures (PCWPmax > 20 mmHg), whereas no patient had elevated pulmonary vascular resistance (PVRmax > 120 dynes x s x cm(-5)). In conclusion, daytime PHT during exercise is frequently seen in patients with OSAS and normal lung function testing and is mainly caused by abnormally high PCWP, whereas PVR seems to play a minor role.

Chronic granulomatous lung infection caused by the dimorphic fungus Emmonsia sp

A 64-year old farmer developed cough, dyspnoea on exertion, and recurrent febrile episodes. X-ray and CT scan revealed bilateral lower lobe opacities in his lungs. A transbronchial biopsy was performed and histopathological findings were interpreted as consistent with a pulmonary necrotizing clear-cell carcinoma and later as a Pneumocystis carinii pneumonia. Due to persistence of symptoms, six months later another lung biopsy was performed and a mould was cultured which was identified by 18S rDNA sequencing as Emmonsia sp. The patient showed some improvement under itraconazole treatment. This is the first description of a human infection with Emmonsia sp. in Germany.

Evaluation of two modified cardiac troponin I enzyme immunoassays

One of the major challenges for manufacturers of troponin immunoassays is to optimize the low-end of the assays because diagnostic and therapeutic interventions are based on decreasing cutpoints. Recently published consensus documents of the European Society of Cardiology and the American College of Cardiology recommended the 99th percentile of a reference control group as cut-off for increased troponin I levels and suggested that imprecision at the 99th percentile for each assay should be < or = 10%. In this study, we have evaluated two newly modified cardiac troponin I (cTnI) enzyme immunoassays (Dimension cTnI assay, Dade Behring, Germany and AIA-PACK cTnI 2nd-Gen, Eurogenetics Tosoh, Belgium). With both assays all measured cTnI values in plasma and serum samples of apparently healthy volunteers were within the reference ranges given by the manufacturers. Intra-assay coefficients of variation of cTnI concentrations above the 99th percentile (given by the manufacturers) were below 17% and decreased with increasing cTnI concentrations. In most samples, the AIA-PACK cTnI assay yielded higher results; however, a close correlation between both assays was observed. Both tests exhibit acceptable overall performance, but (especially the Dimension cTnI assay) do not yet meet the above-mentioned precision in the low-end assay range. These data emphasize the need for cTnI assay standardization and for further optimization at clinical decision levels.

3-deoxy-3-[(18)F]fluorothymidine-positron emission tomography for noninvasive assessment of proliferation in pulmonary nodules

We investigated whether uptake of the thymidine analogue 3-deoxy-3-[(18)F]fluorothymidine ([(18)F]FLT) reflects proliferation in solitary pulmonary nodules (SPNs). Thirty patients with SPNs were prospectively examined with positron emission tomography. Standardized uptake values were calculated for quantification of FLT uptake. Histopathology revealed 22 malignant and 8 benign lesions. Proliferation was evaluated by Ki-67 immunostaining and showed a mean proliferation fraction of 30.9% (range, 1-65%) in malignant SPNs and <5% in benign lesions. Linear regression analysis indicated a significant correlation between FLT-standardized uptake values and proliferative activity (P < 0.0001; r = 0.87). FLT uptake was specific for malignant lesions and may be used for differential diagnosis of SPNs, assessment of proliferation, and estimation of prognosis.

Prospective evaluation of the clinical value of planar bone scans, SPECT, and (18)F-labeled NaF PET in newly diagnosed lung cancer

Previous studies have shown that vertebral bone metastases (BM) not seen on planar bone scintigraphy (BS) might be present on (18)F-fluoride PET scans or at MRI. Therefore, we evaluated the effect of SPECT or (18)F-labeled NaF PET ((18)F PET) imaging on the management of patients with newly diagnosed lung cancer.

METHODS

Fifty-three patients with small cell lung cancer or locally advanced non-small cell lung cancer were prospectively examined with planar BS, SPECT of the vertebral column, and (18)F PET. MRI and all available imaging methods, as well as the clinical course, were used as reference methods. BS with and without SPECT and (18)F PET were compared using a 5-point scale for receiver operating characteristic (ROC) curve analysis.

RESULTS

Twelve patients had BM. BS produced 6 false-negatives, SPECT produced 1 false-negative, and (18)F PET produced no false-negatives. The area under the ROC curve was 0.779 for BS, 0.944 for SPECT, and 0.993 for (18)F PET. The areas under the ROC curve of (18)F PET and BS complemented by SPECT were not significantly different, and both tomographic methods were significantly more accurate than planar BS. As a result of SPECT or (18)F PET imaging, clinical management was changed in 5 patients (9%) or 6 patients (11%), respectively.

CONCLUSION

As indicated by the area under the ROC curve analysis, (18)F PET is the most accurate whole-body imaging modality for screening for BM. Routinely performed SPECT imaging is practicable, is cost-effective, and improves the accuracy of BS.

Effects of chronic nitrate therapy on left-ventricular volume in patients with heart failure secondary to coronary disease already treated with captopril: a withdrawal study

OBJECTIVE

This randomized, double-blind, placebo-controlled study with treatment lasting 16 weeks and withdrawal lasting 6 weeks tried to determine whether stopping nitrates has an effect on left-ventricular end-systolic volume in patients with heart failure who were chronically treated with captopril and diuretics.

PATIENTS AND METHODS

The study group comprised 29 patients with previous myocardial infarction, symptoms of mild-to-moderate heart failure, ejection fraction below 40%, no exercise-induced angina and no electrocardiographic signs of ischemia. After all patients had been treated with captopril (target dose: 25 mg twice daily), diuretics and the study drug (target dose: 40 mg isosorbide dinitrate twice daily or placebo) for 16 weeks, the study drug was withdrawn. The patients were then maintained on captopril and diuretics at constant doses for a 6-week withdrawal period. Radionuclide ventriculography with right-heart catheterization was performed at rest and during supine bicycle exercise after 16 weeks of double-blind treatment and at the end of the 6-week withdrawal period.

RESULTS

The changes in resting parameters following the withdrawal of the study drug were not different between the groups. At comparable maximum workload (placebo group 68 +/- 15 W, nitrate group 68 +/- 20 W), nitrate withdrawal caused a decrease in ejection fraction (placebo withdrawal: +0.8 +/- 4.0%; nitrate withdrawal: -2.7 +/- 4.3%, p < 0.02) and increases in left-ventricular end-diastolic volume (-9 +/- 35 vs. 23 +/- 48 ml, p < 0.02) and end-systolic volume (-9 +/- 33 vs. +24 +/- 47 ml; p < 0.01).

CONCLUSION

The addition of nitrates to a baseline therapy with captopril and diuretics might reduce exercise-induced left-ventricular dilatation in patients with heart failure from coronary disease.

An unusual case of Hughes-Stovin syndrome

In 1959 HUGHES and STOVIN described a syndrome consisting of multiple pulmonary aneurysms and peripheral venous thrombosis. Since that time several cases of the Hughes-Stovin syndrome have been published. We present the case of a 25 yr old man who, in addition to the classical symptoms, had multiple aneurysms of the bronchial arteries, which were the cause of severe haemoptysis. An aneurysm of the left hepatic artery was also detected. To our knowledge this is the first description of aneurysms of the bronchial arteries in Hughes-Stovin syndrome. Bleeding was successfully treated by double embolization of bronchial arteries via transfemoral catheter.

Prognostic value of bisoprolol-induced hemodynamic effects in heart failure during the Cardiac Insufficiency BIsoprolol Study (CIBIS)

BACKGROUND

To further evaluate the mechanism of beta-blocker-induced benefits in heart failure, the relationships between bisoprolol-induced hemodynamic effects and survival were studied during the Cardiac Insufficiency BIsoprolol Study (CIBIS).

METHODS AND RESULTS

In 557 patients studied, bisoprolol significantly reduced heart rate (-16.3+/-15.3 versus -1.6+/-13.4 bpm, respectively; P<.001) compared with placebo at 2 months after inclusion in the study. Heart rate change over time had the highest predictive value for survival (P<.01). Left ventricular fractional shortening (LVFS) significantly increased in the bisoprolol group compared with the placebo group 5 months after inclusion (+0.04+/-0.06 versus -0.001+/-0.05, respectively; P<.001; n=160). LVFS change over time was also significantly correlated with further survival (P<.02 by Cox analysis). Using a nonparametric approach, we demonstrated a significant interaction between study treatment group and LVFS over time. Patients who demonstrated improvement of LVFS over time (82% and 51% of patients in the bisoprolol and the placebo groups, respectively; P<.02) were at lower risk, but the hazard did not further decrease with a further increase of fractional shortening, and there was no significant difference between study treatment groups. Finally, it could be demonstrated that each of the three factors (heart rate change over time, LVFS change over time, and bisoprolol treatment) made a specific contribution to mortality rate.

CONCLUSIONS

Preservation of left ventricular function appears to play a key role in the bisoprolol-induced beneficial effects on prognosis in heart failure. Short-term beta-blocker-induced cardiac effects could provide a means to identify those patients who will experience improved survival over the long term.

Defining the roles of high dose rate endobronchial brachytherapy and laser resection for recurrent bronchial malignancy

Endobronchial therapy is commonly used in the palliative management of malignant disease, but the optimal combinations of treatment modalities (laser, brachytherapy, external beam radiotherapy) have not been defined. We have undertaken a prospective analysis of symptom response, duration of response, and prognostic factors for 117 patients treated with brachytherapy at a single centre, to identify hypotheses suitable for prospective randomised studies. All but one patient had received previous treatment. The percentage of patients with scores of 0 or 1 (none or mild) for each symptom pre-treatment and at 3 months were as follows: cough 62% to 77% (43% improving by at least one grade, N.S.); dyspnoea 32% to 56% (50% improvement by at least one grade, P = 0.0063); haemoptysis 78% to 97%; performance status 65% to 84% (54% by at least one grade, P = 0.0417). An actuarial risk of fatal haemoptysis at 2 years of 20% was associated with prior laser resection (P = 0.048). Death before 2 months was associated with dyspnoea scores of 3 or 4. Suggestions for randomised studies are made to address some of the uncertainties revealed by the analysis.

Reproducibility of left ventricular volume measurements at rest and during bicycle exercise in patients with congestive heart failure: a combined radionuclide and haemodynamic study

A series of 14 patients with heart failure due to coronary artery disease and impaired left ventricular function underwent radionuclide ventriculography with simultaneous thermodilution measurement of cardiac output by pulmonary artery catheter on two occasions (m1, m2) separated by 6 weeks in order to determine the reproducibility of haemodynamic and left ventricular volume measurements at rest and during supine bicycle exercise. The patients were in NYHA grade II or III and had baseline left ventricular ejection fractions below 40%. Derived haemodynamic variables were calculated from the thermodilution cardiac output and from the radionuclide ejection fraction as follows: stroke volume = thermodilution cardiac output/heart rate; left ventricular end-diastolic volume = stroke volume/ejection fraction; left ventricular end-systolic volume = end-diastolic volume - stroke volume. The percentage difference (PD) between each pair of data (m1, m2) was calculated using the following formula: PD = 100% x (m2-m1)/m1. The data showed that reproducible measurements of left ventricular volume can be obtained at rest and during exercise. The mean (+/- S.D.) PD values for end-systolic volume and end-diastolic volume at rest were - 0.1 +/- 17% and - 0.2 +/- 13%, respectively. The mean PD values for end-systolic volume and end-diastolic volume during exercise were - 0.3 +/- 19% and - 0.7 +/- 15%, respectively. By contrast, the reproducibility of the pulmonary capillary wedge pressure measurements was poor, as reflected by a PD value of 14 +/- 51% for exercise pulmonary capillary pressure. Combining radionuclide ventriculography and the thermodilution measurement of cardiac output is useful for measuring left ventricular volume at rest and during exercise in patients with heart failure. This minimally invasive technique allows for a comprehensive assessment of left ventricular performance and appears to be particularly suited for assessing the effects of therapeutic interventions aimed at minimizing the progressive left ventricular enlargement in heart failure.

Effects of bisoprolol on heart rate variability in heart failure

Analysis of heart rate variability (HRV) provides a non-invasive index of autonomic nervous system activity. HRV has been shown to be reduced in heart failure. Preliminary data indicate that beta blockers improve clinical status in patients with heart failure, but HRV improvement remains to be demonstrated. Fifty-four patients from the randomized double-blind, placebo-controlled Cardiac Insufficiency Bisoprolol Study were included in the HRV study. The bisoprolol daily dose was 5 mg once daily. We assessed HRV during 24-hour Holter recordings before randomization and after 2 months of treatment. HRV as measured in the time domain by root-mean-square successive differences (rMSSD), the percentage of adjacent RR differences >50 ms (pNN50), and the SD of RR intervals (SDNN), and in the frequency domain by high-frequency (0.16 to 0.40 Hz) and low-frequency (0.04 to 0.15 Hz) power. Most patients were in New York Heart Association functional class III. The mean left ventricular ejection fraction was 27 +/- 7%, and heart failure was idiopathic or ischemic. After 2 months, the patients receiving bisoprolol had a reduced mean heart rate compared with that in placebo patients (p=0.0004). Bisoprolol increased 24-hour rMSSD (p=0.04) and 24-hour pNN50 (p=0.04), daytime SDNN (p=0.05), and daytime high-frequency power (p=0.03) power. Bisoprolol induced a significant increase in HRV parameters related to parasympathetic activity in heart failure. Increased vagal tone may contribute to the protective effect of beta blockers and may have prognostic implications.

[Microbiological studies of a nasal positive pressure respirator with and without a humidifier system]

13 patients with obstructive sleep apnea syndrome treated with CPAP-therapy and complicating affections of the nasal and pharyngeal mucosa were enrolled in a randomized cross-over study comparing therapy with a heated humidifier (HC 100, company Fisher & Paykel) and treatment with a heat and moisture exchanger (Typ I, company Dahlhausen). We assessed the bacterial and fungal colonisation of the nasal masks of all patients. Samples of mask rinses were taken after the two treatment periods (2 weeks each) and the period without humidification in between. All microbes were found to have pathological potency. There was no significant difference in the total concentration of the microbes in the different treatment modalities. In a few cases however, gram negative bacteria were detected on the masks during humidification with a heated humidifier, but not with heat and moisture exchangers. Legionella spec. were not detectable in any of the samples. Candida albicans was the only fungus detectable. No patient had any infection of the upper or lower respiratory system associated with humidification therapy.

Diagnosis of ornithosis by cell culture and polymerase chain reaction in a patient with chronic pneumonia

We report the case of a woman who had pneumonia due to Chlamydia psittaci. A Chlamydia species was determined to be the causative agent of the pneumonia because it was isolated from bronchoalveolar lavage fluid, because it could be detected in lung biopsy specimens by the direct immunofluorescence technique, and because Chlamydia-specific antibodies could be detected by ELISA and microimmunofluorescence. The infectious agent could not be identified at the species level with use of serological techniques, but the isolate was determined to be C. psittaci by PCR with use of species- and genus-specific sequences within the chlamydial lipopolysaccharide biosynthesis gene gseA. The case reported herein exemplifies the problems encountered in diagnosing ornithosis and shows that isolation of the etiologic agent followed by identification of the species by PCR is helpful in diagnosing this rare disease. In addition, the findings in our case show that laboratory personnel who are conducting tests for Chlamydia pneumoniae should be aware of the risk of accidentally isolating highly infectious C. psittaci organisms.

Lack of effect of nitrates on exercise tolerance in patients with mild to moderate heart failure caused by coronary disease already treated with captopril

OBJECTIVE

To test the hypothesis that the addition of nitrates improves exercise tolerance in patients with heart failure caused by coronary artery disease already treated with an angiotensin converting enzyme inhibitor and diuretics.

DESIGN

Randomised, double blind, placebo controlled, 16 week treatment periods.

SETTING

Outpatient clinic at a university hospital.

PATIENTS

54 patients with previous myocardial infarction, symptoms of mild to moderate heart failure, left ventricular ejection fraction below 40%, no exercise-induced angina or electrocardiographic signs of ischaemia. Four patients in the nitrate group (n = 24) and one patient of the placebo group (n = 25) were withdrawn from the study.

INTERVENTION

After the patients had been on constant doses of captopril and diuretics for at least 2 weeks, they were randomised to receive a target dose of 40 mg isosorbide dinitrate twice daily or placebo in addition to the continuation of captopril and diuretics.

MEASUREMENTS

Bicycle exercise tests with measurement of gas exchange were carried out before randomisation and after 1, 6, 12, and 16 weeks of the double blind treatment. The change in peak oxygen uptake from control to week 16 was prospectively defined as the main outcome measure.

RESULTS

The increase in peak oxygen uptake from before randomisation tended to be greater in the placebo group (before randomisation 17.4 (3.4) ml/min/kg) than in the nitrate group (before randomisation 17.1 (3.5) ml/min/kg) after 12 weeks (mean increase 1.1 (2.7) v 0.0 (2.7) ml/min/kg, p < 0.12) and 16 weeks (1.7 (3.0) v 0.3 (2.6) ml/min/kg, p < 0.14) of treatment.

CONCLUSION

The addition of nitrates to a baseline treatment consisting of captopril and diuretics did not improve exercise tolerance.

Short-term reproducibility of gas exchange measurements during bicycle exercise in patients with mild to moderate congestive heart failure

A series of 45 patients with congestive heart failure due to coronary disease had semisupine bicycle exercise tests (ramp protocol, 10 W/min) on two occasions separated by 3 to 7 days in order to determine the short-term reproducibility of gas exchange measurements during symptom-limited exercise. The percentage difference (PD) between each pair of measurements (m1, m2; PD = 100%.(m2-m1): m1) were calculated. The mean PD values (+/- 1 sigma) and the single determination standard deviations (SDSD) for exercise tolerance (ET, W), peak heart rate (pHR, 1/min), peak oxygen uptake (pVO2, ml/min/kg), peak carbon dioxide output (pVCO2, ml/min/kg), and peak minute ventilation (pVE, l/min) were as follows: [table: see text] No patient reached a plateau of oxygen uptake during the last portion of the ramp exercise test. Thus, pVO2 is not an objective endpoint. The single determination standard deviations show that exercise tolerance and peak oxygen uptake do not differ as to their reproducibility. The absolute values of PD were not a function of exercise tolerance for any of the parameters studied. The PD values for ET and pVO2 were normally distributed. The data suggest that a change in ET and pVO2 must exceed 27% and 28% between two sequential studies in an individual patient in order to be significant at the 5% level, respectively. For the one-tailed test situation, the changes in ET or pVO2 must be greater than 23% in order to be significant.