Hypertensive patients with false-positive thallium-201 scintigraphic results in the infero-posterior wall are in high risk for coronary artery disease development

Myocardial perfusion scintigraphy and echocardiography for detecting coronary artery disease in hypertensive patients: a meta-analysis

PURPOSE

This meta-analysis summarized the accuracy of stress myocardial perfusion scintigraphy (MPS) and stress echocardiography for the diagnosis of coronary artery disease (CAD) in patients with arterial hypertension.

METHODS

We searched for studies in which stress MPS or stress echocardiography were performed to detect CAD in hypertensive patients, with coronary angiography used as the reference test, published from January 1980 to December 2010. Studies performed in patients with known CAD, acute coronary syndrome and previous revascularization procedures were excluded.

RESULTS

Of 1,263 studies, 13 met the inclusion criteria. Pooled summary estimates showed that stress MPS had a sensitivity of 0.90 [95% confidence interval (CI) 0.82-0.95] and a specificity of 0.63 (95% CI 0.53-0.72). For stress MPS, the area under the curve (AUC) at the summary receiver-operating characteristic (SROC) graph was 0.83 (95% CI 0.80-0.86). At meta-regression analysis, the presence of positive stress electrocardiography as inclusion criterion was the only significant effect modifier (p < 0.01). Pooled summary estimates showed that stress echocardiography had a sensitivity of 0.77 (95% CI 0.69-0.83) and a specificity of 0.89 (95% CI 0.83-0.93). For stress echocardiography, the AUC at SROC was 0.91 (95% CI 0.88-0.93). At the meta-regression analysis no significant effect modifier was detected.

CONCLUSION

MPS has high sensitivity for detecting CAD in hypertensive patients, with specificity comparable to that reported in the general population, whereas stress echocardiography shows higher specificity but substantially reduced sensitivity compared to MPS.

Noninvasive techniques to assess myocardial ischemia in hypertensive patients

Hypertensive patients are more affected by coronary artery disease (CAD) than normotensive patients. Currently, established techniques are able to diagnose myocardial ischemia/CAD in hypertensive patients with suspected CAD. An irrevocable role remains for exercise electrocardiogram (ECG) owing to the many parameters evaluated under physiologic conditions. However, the suboptimal specificity of a positive exercise ECG demands further examination of hypertensive patients with either myocardial single-photon emission computed tomography (SPECT) or stress echocardiography, both more specific than exercise ECG in diagnosing CAD. The high specificity of imaging techniques also makes them highly predictive of cardiac events. Additional techniques to help diagnose CAD are available. Tissue Doppler imaging, strain and other echo-derived techniques may add quantitative elements to recognize CAD in hypertensive hearts. The accuracy of MRI is improving to study myocardial function and perfusion. Positron emission tomography and multislice computed tomography, also in-built with fusion scanners, are playing roles in combining coronary angiography and myocardial function/ischemia assessment. However, no significant application of these additional techniques is available for hypertensive patients. Epicardial CAD assessed by coronary angiography remains the gold standard to decide for revascularization procedures. The presence of microcirculatory dysfunction, a symptom typical of hypertensive hearts, is opening up new areas of noninvasive diagnostic techniques for the detection of coronary flow reserve (CFR) and related myocardial ischemia. The quantification of CFR may render this parameter pivotal to deciding the need for revascularization procedures of intermediate coronary stenosis and it may become an additional gold standard in evaluating coronary vessels. Moreover, even with normal epicardial coronary arteries, microcirculation dysfunction bears prognostic stratification capabilities for hypertensive patients and it may become a promising therapeutic target in the near future.