Myocardial perfusion abnormalities in treated hypertensive patients without known coronary artery disease

Non-invasive diagnostic testing for coronary artery disease in the hypertensive patient: potential advantages of a risk estimation-based algorithm

Hypertension is a major risk factor for cardiovascular disease, including coronary atherosclerosis and its clinical manifestations. Non-invasive diagnosis of coronary artery disease in hypertension, however, remains a major clinical challenge. Chest pain frequently occurs in hypertensive patients with and without impairment of coronary blood flow supply. Electrocardiographic abnormalities are also common in these patients, thereby leading to further diagnostic difficulty. On the other hand, international guidelines are rather elusive on the recommended diagnostic pathway for coronary artery disease detection in hypertensive patients.In this article, we review the strengths and limitations of current diagnostic methods used to properly identifying coronary artery disease in hypertensive patients. Furthermore, we analyze the usefulness of adopting preliminary and comprehensive cardiovascular risk stratification, together with the evaluation of markers of organ damage, in order to improve the diagnostic efficacy.Despite the high prevalence of arterial hypertension, we still lack a strategy which would lead to validated and cost-effective clinical decision-making processes in hypertensive patients, which help clinicians to minimize useless, ineffective and expensive diagnostic steps. For this purpose, future guidelines should address the issue of diagnostic strategies for an early identification of hypertensive patients at risk of coronary artery disease. This may facilitate appropriate therapeutic choices to optimize the clinical management of coronary disease in hypertension.

Simultaneous echocardiography and myocardial perfusion single photon emission computed tomography associated with dobutamine stress to predict long-term cardiac mortality in normotensive and hypertensive patients

BACKGROUND

Echocardiography and myocardial scintigraphy associated with dobutamine stress are used for assessing risk in coronary artery disease. We compared the accuracy of the two modalities applied simultaneously for predicting long-term cardiac mortality in normotensive and hypertensive patients.

METHODS

Three hundred and fifty-one consecutive patients underwent dobutamine stress with simultaneous echocardiography and Tc-sestamibi single photon emission computed tomography (SPECT). Fifty patients underwent early (<60 days) revascularization and were excluded; the analysis is based on 301 patients (131 hypertensives and 170 normotensives).

RESULTS

The prevalence of additional risk factors, heart failure, prior myocardial infarction and prior revascularization was similar in the two groups of patients. An abnormal stress echocardiogram was detected in 101 (59%) normotensives and 80 (61%) hypertensives (NS), while 113 (66%) normotensives and 83 (63%) hypertensives (NS) showed abnormal myocardial perfusion. The agreement was 81% (kappa = 0.59) in hypertensives and 82% (kappa = 0.62) in normotensives. During 7.3 +/- 2.8 years of follow-up, 17 (13%) hypertensives and 26 (15%) normotensives died from cardiac causes (P = 0.62). In normotensives, the annual mortality rate was 0.8 for normal echo and 1.3 for normal scan, 2.8 for abnormal echo and 2.6 for abnormal scan. In hypertensives, it was 0.5 for normal echo, 0% for normal scan, 2.6 for abnormal echo and 2.8 for abnormal scan. Each test was associated with higher survival in the case of negative compared to positive results in both normotensive and hypertensive patients (log-rank chi-square 16.4, P < 0.001).

CONCLUSIONS

Dobutamine stress echocardiography and SPECT are equally effective in predicting long-term cardiac death in both normotensive and hypertensive patients.

Prediction of cardiac death in hypertensive patients with suspected or known coronary artery disease by stress technetium-99m tetrofosmin myocardial perfusion imaging

BACKGROUND

There are currently insufficient data to indicate a role for stress myocardial perfusion imaging as a prognostic tool in hypertensive patients.

OBJECTIVES

To assess the incremental value of stress myocardial perfusion imaging for the prediction of cardiac death in hypertensive patients relative to clinical data.

PATIENTS

We studied 601 hypertensive patients (aged 59 +/- 10 years, 387 men) who underwent exercise bicycle or dobutamine (up to 40 microg/kg per min) stress technetium-99m tetrofosmin single photon emission computed tomography (SPECT) for evaluation of coronary artery disease.

OUTCOME

Cardiac death during follow-up. RESULTS; An abnormal scan (reversible or fixed perfusion abnormalities) was detected in 293 (49%) patients (134 had reversible abnormalities). During a mean follow-up period of 3.1 +/- 1.3 years, 109 (18%) patients died; of whom, 42 patients (39%) died due to cardiac causes. Independent predictors of cardiac death were age [hazard ratio = 1.04, 95% confidence interval (CI) 1.01-1.08], history of previous myocardial infarction (hazard ratio = 2, CI 1.1-3.7), stress rate-pressure product (hazard ratio = 0.94, CI 0.87-0.98) and abnormal scan (hazard ratio = 4.7 CI 1.9-11.4). Both reversible and fixed abnormalities were predictive of death. The annual cardiac death rate was 5.3% in patients with an abnormal and 0.5% in patients with a normal perfusion scan.

CONCLUSION

Stress technetium-99m tetrofosmin myocardial perfusion imaging provides prognostic information incremental to clinical data for the prediction of cardiac death in hypertensive patients with known or suspected coronary artery disease.

The diagnosis of coronary artery disease in hypertensive patients with chest pain and complete left bundle branch block: utility of adenosine Tc-99m tetrofosmin SPECT

PURPOSE

Hypertensive patients with complete left bundle branch block who experience chest pain present special problems in the radionuclide diagnosis of coronary artery disease (CAD). The aim of this study was to assess the utility of Tc-99m tetrofosmin SPECT for the diagnosis of CAD in 35 hypertensive patients with left bundle branch block hospitalized for chest pain.

MATERIALS AND METHODS

Images were analyzed semiquantitatively for the presence of both fixed or reversible perfusion defects (method A) or only reversible defects (method B) in the distribution of the left anterior descending artery (LAD) territory. Perfusion defects observed in the territory of any other coronary artery were always considered. Thirty-five patients without infarction underwent adenosine Tc-99m tetrofosmin SPECT, transthoracic echocardiography, and coronary angiography.

RESULTS

The mean left ventricular ejection fraction was calculated as 39.9% +/- 11.6%, and the prevalence of CAD was 29%. The sensitivity of SPECT was identical for the two methods at 89%. The specificity increased 19% with method A and 54% with method B. The positive predictive value remained unsatisfactorily low with both methods (27% for method A and 40% for method B), and the negative predictive value improved from 83% with method A to 93% with method B.

CONCLUSIONS

Only reversible perfusion defects in the LAD territory should be considered significant for CAD, and these patients should undergo coronary angiography. Reversible or fixed perfusion defects in the left circumflex and right coronary artery territories should be evaluated according to other clinical parameters (global left ventricular ejection fraction, extension of perfusion defects). The highly negative predictive value of adenosine SPECT could help in the exclusion of CAD.

Impact of hypertension on the accuracy of exercise stress myocardial perfusion imaging for the diagnosis of coronary artery disease

AIM

To compare the accuracy of exercise stress myocardial perfusion single photon emission computed tomography (SPECT) imaging for the diagnosis of coronary artery disease in patients with and without hypertension.

METHODS

A symptom limited bicycle exercise stress test in conjunction with 99m technetium sestamibi or tetrofosmin SPECT imaging was performed in 332 patients (mean (SD) age, 57 (10) years; 257 men, 75 women) without previous myocardial infarction who underwent coronary angiography. Of these, 137 (41%) had hypertension. Rest SPECT images were acquired 24 hours after the stress test. An abnormal scan was defined as one with reversible or fixed perfusion defects.

RESULTS

In hypertensive patients, myocardial perfusion abnormalities were detected in 79 of 102 patients with significant coronary artery disease and in nine of 35 patients without. In normotensive patients, myocardial perfusion abnormalities were detected in 104 of 138 patients with significant coronary artery disease and in 16 of 57 patients without. There were no differences between normotensive and hypertensive patients in sensitivity (77% (95% confidence interval (CI) 69% to 86%) v 75% (95% CI 68% to 83%)), specificity (74% (95% CI 60% to 89%) v 72% (95% CI 60% to 84%)), and accuracy (77% (95% CI 70% to 84%) v 74% (95% CI 68% to 80%)) of exercise SPECT for diagnosing coronary artery disease. The accuracy of SPECT was greater than electrocardiography, both in hypertensive patients (p = 0.005) and in normotensive patients (p = 0.0001). For the detection of coronary artery disease in individual vessels, sensitivity was 58% (95% CI 51% to 65%) v 57% (95% CI 51% to 64%), specificity was 86% (95% CI 82% to 90%) v 85% (95% CI 81% to 89%), and accuracy was 74% (95% CI 70% to 78%) v 74% (95% CI 70% to 78%) in patients with and without hypertension (NS).

CONCLUSIONS

In the usual clinical setting, the value of exercise myocardial perfusion scintigraphy for diagnosing coronary artery disease is not degraded by the presence of hypertension.