Impact of exercise single-photon emission computed tomographic imaging on appropriateness of coronary revascularization

The Prognostic Value of Normal Exercise Myocardial Perfusion Imaging and Exercise Echocardiography

OBJECTIVES

The purpose of this work was to determine the prognostic value of normal exercise myocardial perfusion imaging (MPI) tests and exercise echocardiography tests, and to determine the prognostic value of these imaging modalities in women and men.

BACKGROUND

Exercise MPI and exercise echocardiography provide prognostic information that is useful in the risk stratification of patients with suspected coronary artery disease (CAD).

METHODS

We searched the PubMed, Cochrane, and DARE databases between January 1990 and May 2005, and reviewed bibliographies of articles obtained. We included prospective cohort studies of subjects who underwent exercise MPI or exercise echocardiography for known or suspected CAD, and provided data on primary outcomes of myocardial infarction (MI) and cardiac death with at least 3 months of follow-up. Secondary outcomes (unstable angina, revascularization procedures) were abstracted if provided. Studies performed exclusively in patients with CAD were excluded.

RESULTS

The negative predictive value (NPV) for MI and cardiac death was 98.8% (95% confidence interval [CI] 98.5 to 99.0) over 36 months of follow-up for MPI, and 98.4% (95% CI 97.9 to 98.9) over 33 months for echocardiography. The corresponding annualized event rates were 0.45% per year for MPI and 0.54% per year for echocardiography. In subgroup analyses, annualized event rates were <1% for each MPI isotope, and were similar for women and men. For secondary events, MPI and echocardiography had annualized event rates of 1.25% and 0.95%, respectively.

CONCLUSIONS

Both exercise MPI and exercise echocardiography have high NPVs for primary and secondary cardiac events. The prognostic utility of both modalities is similar for both men and women.

Diagnostic accuracy of myocardial perfusion imaging in a study population without post-test referral bias

BACKGROUND

Most previous studies on the accuracy of myocardial perfusion imaging (MPI) are hampered by post-test referral bias, in that referral for coronary angiography was influenced by the MPI result. In this way, patients with a normal MPI result less frequently underwent catheterization, a tendency supposed to cause an underestimation of test specificity and an overestimation of test sensitivity.

METHODS AND RESULTS

MPI by use of a gated dual-isotope protocol was undertaken before angiography in 357 patients referred for angiography for suspected stable angina pectoris. The MPI reports were kept secret to prevent post-test referral bias. The MPI study was normal in 215 patients (60%) and showed reversible perfusion abnormalities in 118 (33%) and fixed defects in 24 (7%). Angiography was normal in 231 patients (65%) and revealed 1 or more significant stenoses in 126 (35%). With angiography as the reference, the sensitivity and specificity of MPI for detecting significant coronary artery stenosis were 75% and 79%, respectively.

CONCLUSIONS

In this prospective study without post-test referral bias, we found a lower sensitivity and slightly higher specificity than in studies with post-test referral bias. The imperfect accuracy may reflect differences between anatomic and physiologic imaging.

Predictors of Revascularization Among Emergency Department Patients who are Evaluated for Acute Coronary Syndrome

BACKGROUND

To determine, among patients who present to the emergency department with symptoms suggestive of acute coronary syndrome (ACS), predictors of short-term revascularization.

METHODS

A prospective descriptive trial was performed. Potential predictors for revascularization were measured by means of a questionnaire of providers, serum for cardiac biomarkers, and an initial ECG. The primary outcome of revascularization (coronary bypass graft or percutaneous intervention) was determined through a medical record review. Potential predictors of revascularization were entered into a family of logistic regressions.

RESULTS

341 eligible subjects were enrolled, of whom 14% underwent revascularization. The predictors of revascularization included ST elevation on initial ECG (odds ratio 12.0), and an elevation in troponin I (odds ratio 8.9), CKMB (odds ratio 6.8), or myoglobin (odds ratio 4.7) on admission. When all three biomarkers competed in the same model, troponin I appeared to be the strongest predictor of short-term revascularization.

CONCLUSION

In a single site study, among emergency department patients with symptoms suggestive of ACS, ST elevation on initial ECG and an elevation in troponin I, CK-MB, and myoglobin upon presentation all predicted short -term revascularization. Among the three biomarkers, elevation in troponin I was the strongest predictor. ABBREVIATED ABSTRACT: We conducted a prospective descriptive trial to identify predictors of short-term revascularization among 341 emergency department patients who presented with symptoms suggestive of ACS. Fourteen percent of the study population received revascularization. Predictors of revascularization included ST elevation on initial ECG (odds ratio 12.0.), and an elevation in troponin I (odds ratio 8.9), CKMB (odds ratio 6.8), or myoglobin (odds ratio 4.7) on admission. When all three biomarkers competed in the same model, troponin I appeared to be the strongest predictor of short-term revascularization.

Evaluation of the pathophysiology of odontogenic maxillary sinusitis using bone scintigraphy

The inflammatory changes in the maxillary sinus mucosa and wall (mucosal and bony lesions) were evaluated to identify the pathophysiology of odontogenic maxillary sinusitis. Out of 80 patients who underwent CT, 32 patients were examined using single photon emission computerized tomography (SPECT) bone scintigraphy (bone SPECT) with 99mTc-hydroxymethylene-diphosphonate. Mucosal and bony lesions were evaluated morphologically on both images. SPECT data were used to assess the bone activity by calculating the count ratios of the causative alveolar process over the cervical vertebrae. The relationships with clinical symptoms, mucosal changes around the maxillary ostium (ostial lesions), and radiolucencies around the causal teeth (periapical lesions) were assessed. Bone SPECT showing the causal site was valuable for aiding a definitive diagnosis. Mucosal lesions tended to exceed bony lesions horizontally and vertically. Bony lesions tended to extend posteriorly and then anteriorly. The vertical extent of mucosal lesions and the horizontal and vertical extent of bony lesions were correlated with the presence of facial symptoms, ostial lesions, and periapical lesions. Bone activity was significantly correlated with the horizontal and vertical extent of mucosal lesions, horizontal extent of bony lesions, and presence of infraorbital symptoms, ostial lesions, and periapical lesions. Bone activity caused by alveolitis affects the pathophysiology of this disease.

Diagnostic value of spect bone scintigraphy for odontogenic maxillary sinusitis

PURPOSE

The aim of this study was to assess the diagnostic value of bone SPECT for odontogenic maxillary sinusitis and bone activity in the alveolar process to clarify the pathophysiologic nature of the disease.

MATERIALS AND METHODS

Computed tomography and bone SPECT with Tc-99m HMDP were performed in 28 patients with odontogenic maxillary sinusitis. Based on the findings of the computed tomographic images, the inflammatory changes in the maxillary sinus mucosa (mucosal lesions) were evaluated horizontally and vertically. For the initial diagnosis, visualization of the causative site by bone SPECT was compared with conventional radiographic and planar findings. SPECT data were used to assess bone activity by calculating the mean count ratios of the alveolar process over the cervical vertebrae. The relation of bone activity to the structure of the mucosal lesions, the presence of clinical symptoms, mucosal changes around the maxillary ostium (ostial lesions), and conventional radiolucent images around the causative teeth (periapical lesions) were assessed.

RESULTS

Identification of the causative site was sufficiently specific in bone SPECT images. Bone activity was significantly correlated with the structure of the mucosal lesions, both horizontally and vertically, and with the presence of infraorbital symptoms, ostial lesions, and periapical lesions.

CONCLUSIONS

It is important to view odontogenic maxillary sinusitis as a bone disease in which the bone activity associated with alveolar osteitis affects the pathophysiologic nature of the disease. Bone SPECT is valuable to make a more precise diagnosis, thereby allowing more appropriate treatment of the disease.