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

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.

[Silent ischemia versus angina in Tl-201 tomoscintigraphy]

INTRODUCTION

The aim of this work was to describe the variables associated to silent ischemia in patients with reversible perfusion defects in poststress myocardial perfusion scintigraphy.

METHODS

Tl-201 myocardial perfusion SPECT of 522 patients showing total or partially reversible perfusion defects after exercise testing were quantitatively analyzed retrospectively. Relationship between silent ischemia, size of perfusion defect and presence of risk factors was performed.

RESULTS

Ischemia was silent in 412 (73 %) patients. In 176 (33 %) patients exercise test was electrically positive. There were no differences in perfusion defect size between patients with and without angina in exercise test (27 +/- 12 vs 27 +/- 14), but patients with angina had a greater degree of reversibility, in left descending artery (LDA) territory (56 +/- 40 vs 45 +/- 40 p < 0.01). Silent ischemia was more frequently observed in patients with previous acute myocardial infarction (46 % vs 35 %). There was no relationship between the production of exertional angina and the presence of risk factors.

CONCLUSIONS

A high number of patients with reversible perfusion defects on SPECT had silent ischemia. Patients with angina during exercise test had more defect reversibility in LDA territory. Silent ischemia is more frequent in patients with previous acute myocardial infarction.

[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.

[Morphologic classification of hypertrophic cardiomyopathy with myocardial single photon emission tomography. Comparison with echocardiographic classification]

INTRODUCTION AND OBJECTIVES

The aim of this study was to compare different morphologic types of hypertrophic cardiomyopathy obtained by single photon emission tomography to those obtained by echocardiogram.

MATERIALS AND METHODS

In 76 (64%) out of 119 patients with hypertrophic cardiomyopathy the echocardiogram permitted an optimal visualization of all left ventricular segments in the short axis view and consequent classification to one of the six morphological types: type I (septal anterior hypertrophy), type II (septal anterior and septal posterior hypertrophy), type III (septal and antero-lateral hypertrophy), type IV (antero-lateral and/or septal posterior hypertrophy), type V (concentric hypertrophy) and type VI (apical hypertrophy). Without knowledge of echo data, two experienced observers included the short axis of single photon emission tomography images at rest (99mTc-tetrofosmin) to one of those types.

RESULTS

Global concordance between echocardiogram and single photon emission tomography was 75%. Type III was the most frequent both in echo (76%) and in single photon emission tomography (74%) and type III produced the majority of discrepancies. SPET identified 4 patients with a predominant septal and inferior hypertrophy, that did not correspond to any of the 6 types of echocardiographic classification and had been previously classified as type III by echo in 3 cases and as type V in 1 case.

CONCLUSIONS

There was agreement between echo and single photon emission tomography in the morphological classification of most of the patients (75%) with hypertrophic cardiomyopathy. Nevertheless, some discrepancies were observed for the type III echocardiogram.