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

Diagnostic Value of Single-Photon Emission Tomography Stress Test in Patients With Suspected Coronary Artery Disease in Saudi Arabia

Background

Invasive coronary angiography (ICA) is the gold standard procedure for the diagnosis of coronary artery disease (CAD). ICA allows for clear visualization of the coronary arterial blood flow. Single-photon emission computed tomography (SPECT) is currently in widespread use to non-invasively evaluate patients known or suspected of coronary artery disease (CAD). This study aimed to examine the association between (SPECT) stress test and elective ICA in terms of diagnostic value in patients suspected of coronary artery disease at the King Faisal Cardiac Center (KFCC), Jeddah, Saudi Arabia.

Methods

This study is a retrospective diagnostic validation study using a consecutive sampling technique to select the study sample at KFCC. The study included all patients who presented with chest pain that were investigated with either exercise or pharmacologic myocardial perfusion SPECT study followed by elective ICA within six months from January 2015 to January 2020.

Results

A total of 207 patients met the inclusion criteria, where 43% (n = 90) of patients were females and 57% (n = 117) were males; 68% (n = 141) of the patients had both test results concordant (both SPECT and ICA results were in agreement). In 32% of the patients (n = 66), there was a discordant result (discrepant result between SPECT and ICA). SPECT had a sensitivity of 92.4% and a specificity of 26.3%. SPECT had a negative predictive value of 0.68 and a positive predictive value of 0.66 compared to ICA. There was a low degree of reliability between SPECT and ICA.

Conclusion

Reliability between the SPECT and ICA in exclusion of significant CAD is high. The rate of false-positive tests was high while the accuracy of SPECT in detecting CAD in patients with diabetes and hypertension was high. The overall reliability of SPECT to ICA in the Saudi population was low.

Predictors of silent myocardial ischemia in resistant hypertensive patients

BACKGROUND

Hypertension is the most prevalent and significant modifiable risk factor for coronary heart disease. A portion of patients with uncontrolled hypertension are considered to have resistant hypertension (RHTN). Myocardial ischemia incidence increases along with blood pressure (BP) levels. However, the prevalence of myocardial ischemia in patients with RHTN, as well as the factors associated with it, is unknown.

METHODS

We enrolled 129 patients with true RHTN regularly followed in our specialty hypertension clinic and evaluated then by resting and dipyridamole pharmacological stress myocardial perfusion scintigraphy. Patients were then divided into 2 groups: those with (I-RHTN; n = 36) and those without (NI-RHTN; n = 93) myocardial ischemia. Echocardiography, 24-hour ambulatory BP monitoring (ABPM), and flow mediated dilation (FMD) were also evaluated.

RESULTS

Thirty six (28%) patients had myocardial ischemia. There was no difference between groups regarding age, sex, biochemical parameters, office, and 24-hour ABPM levels. Patients in the I-RHTN group were more likely diabetic (31% vs. 11%; P < 0.05) and obese (75% vs. 40%; P < 0.001). Adjusting for age and body mass index, multiple logistic regression showed that diabetes (odds ratio (OR) = 6.5; 95% confidence interval (CI) = 1.06-40.14; P = 0.04), FMD (OR = 0.18; 95% CI = 0.07-0.41; P < 0.001), heart rate (OR = 1.23; 95% CI = 1.11-1.36; P < 0.001), left ventricular mass index (OR = 1.02; 95% CI = 1.01-1.04; P = 0.04), and microalbuminuria (OR = 1.02; 95% CI = 1.01-1.04; P = 0.002) were independent predictors of ischemia.

CONCLUSIONS

In conclusion, there is a high prevalence of myocardial ischemia in patients with RHTN. Increased microalbuminuria, heart rate, endothelial dysfunction, and left ventricular mass can be useful to guide the investigation for myocardial ischemia in these high risk patients.

A head-to-head comparison of the coronary calcium score by computed tomography with myocardial perfusion imaging in predicting coronary artery disease

Objectives

The coronary artery calcium (CAC) score has been shown to predict future cardiac events. However the extent to which the added value of a CAC score to the diagnostic performance of myocardial perfusion imaging (MPI) by single photon emission computed tomography (SPECT) is unclear. The purpose of this study is to investigate the correlation between CAC score and SPECT in patients with suspected coronary artery disease.

Methods

A retrospective review of the CAC scores by use of the Agatston calcium scoring method and cardiac SPECT diagnostic reports was conducted in 48 patients, who underwent both coronary computed tomography (CT) and SPECT examinations due to suspected coronary artery disease. A Pearson correlation test was used to determine the relation between CAC scores and MPI-SPECT assessments with regard to the evaluation of the extent of disease.

Results

Forty-seven percent of the patients had CAC scores more than 100, while 42% of these patients demonstrated abnormal, or probably abnormal, MPI-SPECT. Of the 23% of patients with a zero CAC score, only 7% had normal MPI-SPECT findings. No significant correlation was found between the CAC scores and MPI-SPECT assessments (r value ranged from 0.012 to 0.080), regardless of the degree of coronary calcification.

Conclusions

There is a lack of correlation between the CAC scores and the MPI-SPECT findings in the assessment of the extent of coronary artery disease. CAC scores and MPI-SPECT should be considered complementary approaches in the evaluation of patients with suspected 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.

Early detection of coronary artery flow and myocardial perfusion impairment in hypertensive patients evidenced by myocardial blush grade (MBG) and thrombolysis in myocardial infarction (TIMI) frame count (TFC)

OBJECTIVE

In hypertensive patients with typical chest pain but absence of coronary stenosis the coronary microcirculation may be impaired, thus, our study aimed to appraise, in these subjects, the role of the coronary microcirculation, assessed by Myocardial Blush Grade (MBG) and Thrombolysis in Myocardial Infarction (TIMI) Frame Count (TFC).

METHODS

A total of 95 subjects with chest pain and uninjured coronary arteries were recruited into the study: 80 subjects were hypertensive while 15 subjects were normotensive. The hypertensive subjects were divided into two subgroups: hypertensive subjects with positive scintigraphy and hypertensive subjects with negative scintigraphy. The TFC, a quantitative method of assessing coronary artery flow, the MBG, an assessment of the level of tissue perfusion, and the Total Myocardial Blush Score (TMBS), the sum of the myocardial blush grades of each coronary territory, were evaluated on the coronary angiogram of every patient.

RESULTS

The TFC was higher (p<0.05) in hypertensive subjects than in normotensive subjects. The MBG and the TMBS were lower (p<0.05) in hypertensive subjects than in normotensive subjects. The TFC was higher (p<0.05) in positive scintigraphy than in negative scintigraphy. The MBG was lower (p<0.05) in positive scintigraphy than in negative scintigraphy. The Spearman rank correlation test showed that the TFC and the MBG was inversely associated.

CONCLUSION

The hypertensive subjects had impaired coronary artery flow and myocardial perfusion, documented by the TFC, MBG and myocardial perfusion scintigraphy. These methods may be universally applicable, in fact they are validated and most catheterization laboratories have access to them.

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.

Myocardial perfusion imaging analysis in patients with regurgitant valvular heart disease

BACKGROUND/AIM

We noticed that there was decreased correlation of the findings from myocardial perfusion imaging (MPI) and cardiac catheterization (CATH) in patients with mitral regurgitation (MR) and aortic regurgitation (AR) compared to patients without valve disease.

METHODS

Through a systematic review of MPI records at the Harry S. Truman Memorial Veterans' Hospital between 1998 and 2008, we identified 58 patients with at least moderate MR or AR by echocardiogram who underwent cardiac catheterization within 6 months of the MPI study. A control group was formulated with 60 patients who did not have significant MR or AR on echocardiogram and who had both MPI and CATH. Correlation between MPI and CATH was graded as complete, partial, or absent.

RESULTS

Correlation between MPI and CATH was lower in the valve disease patients (study group) when compared to controls. Correlation was complete in 76% of study patients and 90% of controls, partial in 15% of study patients and 5% of controls, and absent in 9% of study patients and 5% of controls. Differences between the groups were significant (P < .05).

CONCLUSIONS

Patients with regurgitant valvular heart disease may have myocardial perfusion abnormalities that are not associated with angiographic critical coronary stenosis.

Diagnostic value of SPECT, PET and PET/CT in the diagnosis of coronary artery disease: A systematic review

PURPOSE

The purpose of the study was to investigate the diagnostic value of SPECT, PET and PET/CT in the diagnosis of coronary artery disease, based on a systematic review.

MATERIAL AND METHODS

A search of PubMed/Medline and Sciencedirect databases in the English-language literature published over the last 24 years was performed. Only studies with at least 10 patients comparing SPECT, PET or combined PET/CT with invasive coronary angiography in the diagnosis of coronary artery disease (50% stenosis) were included for analysis. Sensitivities and specificities estimates pooled across studies were analysed using a Chi-square test.

RESULTS

Twenty-five studies met the selection criteria and were included for the analysis. Ten studies were performed with SPECT alone; while another six studies were performed with PET alone. Five studies were carried out with both PET and SPECT modalities, and the remaining four studies were investigated with integrated PET-CT. The mean value of sensitivity, specificity and accuracy of these imaging modalities for the diagnosis of coronary artery disease was 82% (95%CI: 76 to 88), 76% (95%CI: 70 to 82) and 83% (95%CI: 77 to 89) for SPECT; 91% (95%CI: 85 to 97), 89% (95%CI: 83 to 95) and 89% (95%CI: 83 to 95) for PET; and 85% (95%CI: 79 to 90), 83% (95%CI: 77 to 89) and 88% (95%CI: 82 to 94) for PET/CT, respectively. The diagnostic accuracy of these imaging modalities was dependent on the radiotracers used in these studies, with ammonia resulting in the highest diagnostic value.

CONCLUSION

Our review shows that PET has high diagnostic value for diagnosing coronary artery disease, and this indicates that it is a valuable technique for both detection and prediction of coronary artery disease.

Clinical utility of estimated glomerular filtration rate in patients undergoing gated SPECT

BACKGROUND

Chronic kidney disease is a major risk factor for coronary artery disease (CAD). The aim of the study was to examine the association between estimated glomerular filtration rate (GFR), presence of CAD, and prognosis in patients with reversible perfusion defects at gated single-photon emission computed tomography (g-SPECT).

METHODS

Six hundred fifty-eight subjects who had undergone stress/rest g-SPECT for evaluation of myocardial ischemia were divided into two groups according to the presence of CAD, defined by a 70% diameter stenosis in at least one major vessel or principal side branch at coronary angiography.

RESULTS

GFR was lower in patients with CAD and after adjusting for several clinical characteristics through multivariate logistic regression analysis, reduced (<60 mL/min/1.73 m(2)) GFR remained a significant predictor of CAD (HR 1.80, 95% CI 1.04 to 3.12, P = .036). In addition, reduced GFR was associated with a greater extent of myocardial ischemia, assessed through the summed difference score, as well as with an increase in both total and cardiac mortality.

CONCLUSIONS

In patients with a positive g-SPECT scan, GFR is an accurate marker of CAD and is directly correlated to the extent of myocardial ischemia. Furthermore, reduced GFR had an adverse impact on survival in this particular population.

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.

Hypertensive response with exercise does not increase the prevalence of abnormal Tc-99m SPECT stress perfusion images

BACKGROUND

Systemic hypertension and an exaggerated blood pressure (BP) response with exercise have been associated with 'false-positive' findings on stress electrocardiography and echocardiography; however, limited data is available for stress myocardial perfusion imaging (MPI). The purpose of this study was to investigate whether an exaggerated elevation in BP with exercise is associated with an increased prevalence of abnormal MPI.

METHODS

BP responses to exercise were assessed in a cohort of 7,205 patients who underwent stress testing with technetium 99m-SPECT MPI (7/1999-6/2005) for the evaluation of chest pain or dyspnea.

RESULTS

A hypertensive response, defined as a peak systolic BP > or = 220 mmHg, occurred in 355 (4.9%) and was not associated with higher rates of ischemic ECG changes (16.1 versus 16.6%; P = .7), differences in Duke treadmill scores (4.7 +/- 4 versus 5.1 +/- 5; P = .3) or an increased prevalence of abnormal perfusion images (30.1% versus 32.9%; P = .3) to those without a hypertensive exercise response. Patients with a hypertensive response and either intermediate or high-risk MPI (on the basis of summed-difference-scores) referred for coronary angiography, had a high prevalence of coronary artery disease which was similar to those without a hypertensive response (88% versus 83%; P = .5). In an analysis of a community-based patient subset, a hypertensive response was not associated with a difference in either all-cause mortality or subsequent myocardial infarction, coronary revascularization or cardiac death (8% versus 9%; P = .7).

CONCLUSION

A hypertensive BP response to exercise is not associated with increased rates of ischemic ECG changes, higher-risk Duke treadmill scores, greater degrees of abnormal MPI or worse clinical outcome.

High probability of disease in angina pectoris patients: is clinical estimation reliable?

BACKGROUND

According to most current guidelines, stable angina pectoris patients with a high probability of having coronary artery disease can be reliably identified clinically.

OBJECTIVES

To examine the reliability of clinical evaluation with or without an at-rest electrocardiogram (ECG) in patients with a high probability of coronary artery disease.

PATIENTS AND METHODS

A prospective series of 357 patients referred for coronary angiography (CA) for suspected stable angina pectoris were examined by a trained physician who judged their type of pain and Canadian Cardiovascular Society grade of pain. Pretest likelihood of disease was estimated, and all patients underwent myocardial perfusion scintigraphy (MPS) followed by CA an average of 78 days later. For analysis, the investigators focused on the approximate groups of patients with more severe disease, ie, typical angina (n=187), Canadian Cardiovascular Society grade 2 pain or higher (n=176) or high (higher than 85%) estimated pretest likelihood of disease (n=142).

RESULTS

In the three groups, 34% to 39% of male patients and 65% to 69% of female patients had normal MPS, while 37% to 38% and 60% to 71%, respectively, had insignificant findings on CA. Of the patients who had also an abnormal at-rest ECG, 14% to 21% of men and 42% to 57% of women had normal MPS. Sex-related differences were statistically significant.

CONCLUSIONS

Clinical prediction appears to be unreliable. Addition of at-rest ECG data results in some improvement, particularly in male patients, but it makes the high probability groups so small that the addition appears to be of limited clinical relevance.

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.

Usefulness of the exercise electrocardiogram in diagnosing ischemic or coronary heart disease in patients with chest pain

We compared exercise electrocardiograms with myocardial perfusion images and coronary angiograms in 186 patients who had been referred to coronary angiography for stable angina pectoris. All had normal electrocardiographic findings at rest, and none had undergone coronary revascularization. Sensitivity, specificity, and positive and negative predictive values with the exercise electrocardiogram for prediction of reversible and/or irreversible hypoperfusion were 58%, 89%, 76%, and 77% and 70%, 88%, 72%, and 87%, respectively, for prediction of reversibility only. Corresponding values for comparison with coronary angiography were 65%, 89%, 74%, and 83%, respectively. Sensitivities were considerably lower in women than in men. Exercise electrocardiographic findings were normal in 50% of women and 25% of men who had reversible perfusion defects.

Prognostic value of dobutamine stress echocardiography in patients with systemic hypertension and known or suspected coronary artery disease

Currently, there are no outcome data to suggest an incremental value of stress echocardiography in the risk stratification of patients who have hypertension after controlling for the left ventricular mass index (LVMI). This study assessed the incremental value of dobutamine stress echocardiography (DSE) for the prediction of mortality rate and cardiac events in patients who have hypertension. We studied 596 patients who had hypertension (mean age 62 +/- 12 years; 382 men) and who underwent DSE for evaluation of known or suspected coronary artery disease. End points during follow-up were hard cardiac events (cardiac death and nonfatal myocardial infarction) and total mortality rate. Left ventricular hypertrophy was detected by echocardiography in 119 patients (20%). During a median follow-up of 3 years, 101 patients (17%) died (43 cardiac deaths) and 19 patients had nonfatal myocardial infarction. In an incremental multivariate analysis model, clinical predictors of hard cardiac events were age, history of congestive heart failure, and LVMI. The percentage of abnormal myocardial segments examined with DSE was incremental to the clinical model (chi square 41 vs 27, p <0.001). Clinical predictors of total mortality rate were age, smoking, hypercholesterolemia, history of congestive heart failure, and LVMI. The peak wall motion score index was incremental to the clinical model (chi square 45 vs 40, p <0.05). DSE provides incremental data for the prediction of mortality rate and hard cardiac events in patients who have hypertension after adjustment for clinical data and LVMI.

The use of "overall accuracy" to evaluate the validity of screening or diagnostic tests

OBJECTIVE

Evaluations of screening or diagnostic tests sometimes incorporate measures of overall accuracy, diagnostic accuracy, or test efficiency. These terms refer to a single summary measurement calculated from 2 x 2 contingency tables that is the overall probability that a patient will be correctly classified by a screening or diagnostic test. We assessed the value of overall accuracy in studies of test validity, a topic that has not received adequate emphasis in the clinical literature.

DESIGN

Guided by previous reports, we summarize the issues concerning the use of overall accuracy. To document its use in contemporary studies, a search was performed for test evaluation studies published in the clinical literature from 2000 to 2002 in which overall accuracy derived from a 2 x 2 contingency table was reported.

MEASUREMENTS AND MAIN RESULTS

Overall accuracy is the weighted average of a test's sensitivity and specificity, where sensitivity is weighted by prevalence and specificity is weighted by the complement of prevalence. Overall accuracy becomes particularly problematic as a measure of validity as 1) the difference between sensitivity and specificity increases and/or 2) the prevalence deviates away from 50%. Both situations lead to an increasing deviation between overall accuracy and either sensitivity or specificity. A summary of results from published studies (N = 25) illustrated that the prevalence-dependent nature of overall accuracy has potentially negative consequences that can lead to a distorted impression of the validity of a screening or diagnostic test.

CONCLUSIONS

Despite the intuitive appeal of overall accuracy as a single measure of test validity, its dependence on prevalence renders it inferior to the careful and balanced consideration of sensitivity and specificity.

Prognostic significance of fixed perfusion abnormalities on stress technetium-99m sestamibi single-photon emission computed tomography in patients without known coronary artery disease

Fixed perfusion abnormalities in patients with known coronary artery disease (CAD) are associated with myocardial damage and adverse outcomes. However, the significance of these abnormalities in patients without known CAD is unclear. The aim of this study was to assess the prognostic significance of fixed versus reversible perfusion abnormalities in patients without known CAD. We studied 327 patients (58 +/- 11 years of age; 215 men) with no history of myocardial infarction or revascularization, who demonstrated myocardial perfusion abnormalities on stress (exercise or dobutamine) sestamibi tomographic imaging. Follow-up end points were all-cause mortality and hard cardiac events (cardiac death and nonfatal myocardial infarction). Myocardial perfusion abnormalities were reversible in 226 patients (69%) and fixed in 101 patients (31%). During a mean follow-up of 7 years, 72 patients (22%) died (cardiac death in 30) and 15 patients had nonfatal myocardial infarctions. The annual mortality rate was higher in patients with fixed abnormalities than in those with reversible abnormalities (4.4% vs 2.7%, p <0.01), whereas the annual hard cardiac event rate was not significantly different between the 2 groups (2.5% vs 2%). In a multivariate analysis model, the summed stress score was an independent predictor of hard cardiac events (risk ratio 1.7, 95% confidence interval 1.3 to 5.4). The presence of a fixed perfusion abnormality was independently associated with an increased risk of death after adjustment for clinical and stress test data and the summed stress score (risk ratio 2.5, 95% confidence interval 1.3 to 3.7). In patients with suspected, but no history of CAD, fixed perfusion abnormalities were associated with a higher risk of death compared with reversible perfusion abnormalities.

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.