How can we diagnose coronary heart disease in hypertensive patients?

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.

The contribution of hypertension to black-white differences in likelihood of coronary artery disease detected during elective angiography

BACKGROUND

Black patients in the United States undergoing angiography for suspected coronary artery disease (CAD) have consistently been found to have less disease than whites. As the effects of hypertension are greater in blacks than whites, and hypertensive heart disease may mimic CAD and lead to catheterization, we examined the association between race and hypertension as an explanation for the disparities in angiographic CAD.

METHODS

Using an academic hospital's institutional database, we studied patients undergoing first-time elective angiography from 2001 to 2008. Using multivariable logistic regression with data on patient demographics, CAD risk factors, and coronary stenoses, we compared rates of angiographic disease for blacks and whites, creating models separately for patients with and without hypertension. We then tested the significance of an interaction term between race and hypertension on angiographic findings.

RESULTS

We identified 1,203 black and 2,538 white patients who underwent initial elective angiography. Black patients were less likely to have a significant stenotic lesion (≥50% stenosis in the left main artery or ≥70% stenosis elsewhere) than whites (adjusted risk ratio 0.65; 95% confidence interval (CI) 0.55-0.75). Among patients with hypertension this difference was exaggerated (adjusted risk ratio 0.60; 95% CI 0.51-0.71). However, among patients without hypertension, the risk of having a significant lesion was similar in blacks and whites (adjusted risk ratio 0.97; 95% CI 0.67-1.37). The interaction term for race and hypertension was confirmed as statistically significant.

CONCLUSIONS

Among patients electively referred for angiography, hypertension, and its effects may contribute to the lower rate of CAD found in blacks compared to whites.

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.

Usefulness of stress echocardiography for risk stratification and prognosis of patients with left ventricular hypertrophy

The purpose of this study was to evaluate the role of stress echocardiography in the risk stratification and prognosis of patients with left ventricular (LV) hypertrophy. One thousand two patients (mean age 62 +/- 13 years, 35% men) with LV hypertrophy (defined by LV mass index >115 g/m(2) for men and >95 g/m(2) for women) were evaluated. LV mass was calculated using the linear dimension method, as recommended by the American Society of Echocardiography. The calculation of relative wall thickness was performed using the formula (2 x posterior wall thickness)/LV internal diameter. Concentric and eccentric LV hypertrophy were defined as relative wall thicknesses > or =0.42 and <0.42 cm, respectively. Follow-up (2.6 +/- 1.1 years) for confirmed myocardial infarction and cardiac death (n = 71) was obtained. Four hundred seventy-three patients (47%) had concentric hypertrophy, and 529 patients (53%) had eccentric hypertrophy. In patients with either concentric or eccentric LV hypertrophy, stress echocardiography was able to effectively risk-stratify normal versus abnormal subgroups (event rate 1.1% vs 4.9% per year, p <0.0001), whereas stress electrocardiography was unable to do so. In the cohort with normal stress echocardiographic results, patients with concentric LV hypertrophy had an event rate 5 times higher than those with eccentric LV hypertrophy (event rate 1.7% vs 0.3% per year, p = 0.007). In conclusion, stress echocardiography effectively risk-stratifies patients with LV hypertrophy compared with stress electrocardiography. Normal stress echocardiographic results in patients with concentric LV hypertrophy indicate a worse prognosis than in patients with eccentric LV hypertrophy, probably reflecting decreased sensitivity in this cohort. However, abnormal stress echocardiographic results portend a worse prognosis in patients with either concentric or eccentric LV hypertrophy.

Aortic Dissection

Aortic root enlargement is generally asymptomatic, with few clinical clues, but may be observed as an incidental finding on a chest x-ray, echocardiogram, or contrast-enhanced computerized tomogram of the chest. Aortic dissection is one of the most feared complications of hypertension. A history of hypertension is commonly present, but the systolic blood pressure in type A dissection (proximal to the left subclavian artery) has been found to be less than 150 mm Hg in 64% of patients. However, 71% of type B dissections (distal to the left subclavian artery) present with a systolic blood pressure 150 mm Hg or higher (International Registry of Acute Aortic Dissection). Most frequently, onset of symptoms is in the daytime, especially between 6 a.m. and noon. Severe sharp chest pain that is abrupt in onset is the most likely presentation. Migrating pain is uncommon. Although a pulse deficit with decreased or absent carotid, brachial, or femoral pulses occurs in only 30% of patients, three or more deficits predict an in-house mortality of about 60%. A chest x-ray finding of a widened mediastinum is present in 62.6% of type A and 56% of type B dissections. Contrast-enhanced computerized tomography or transesophageal echocardiography is the most commonly performed procedure for diagnosis. In-house mortality has been found to be 32.5% in type A dissections and 13% in type B dissections.

Hypertensive heart disease

Hypertensive heart disease encompasses anatomical changes and altered physiology of heart muscle, coronary arteries, and great vessels. Left ventricular hypertrophy is not only a target organ response to increased afterload, but is also the most potent cardiovascular risk factor. Regression of hypertrophy reduces morbidity and mortality. Heart failure may be present in the absence of a reduction of myocardial contractility. Ischemic heart disease occurs in the absence of epicardial coronary disease. Left atrial size and atrial fibrillation are associated. Potentially lethal ventricular arrhythmias and sudden cardiac death are more common in hypertensive patients. The relationship of aortic root size to blood pressure is weaker than expected; however, the relationship to aortic dissection is stronger. Careful attention and treatment of left ventricular hypertrophy, heart failure, ischemic heart disease, and atrial fibrillation will improve survival.

Exercise versus recovery electrocardiography for predicting outcome in hypertensive patients with chest pain

BACKGROUND

Exercise electrocardiography has limited prognostic accuracy in hypertensives because of unsatisfactory specificity. We prospectively used comparative stress-recovery heart rate-adjusted ST (ST/HR) analysis to predict mortality in a consecutive population of hypertensives with chest pain.

METHODS

The stress-recovery index (SRI), defined as the difference between ST/HR areas during exercise and recovery, was derived in 460 hypertensive with known (n=360, 78%) or suspected (n=100, 22%) coronary artery disease. To assess whether it added prognostic information to routinely obtained information, clinical data, the resting ejection fraction, and exercise testing data were entered into a sequential Cox's model; the SRI was entered last. Model validation was performed by bootstrap adjusted by the degree of optimism in estimates. Survival analysis was performed using the product-limit Kaplan-Meier method.

RESULTS

During a median follow-up of 28 months (interquartile range, 13-44 months), 32 (7%) patients died, 23 (5%) suffered from acute myocardial infarction and 60 (13%) underwent late (> 3 months) revascularization. Male gender (hazard ratio, 1.53; 95% confidence interval, 1.01-2.34), peak double product (hazard ratio, 0.70; 95% confidence interval, 0.54-0.90) and the SRI (hazard ratio, 0.69; 95% confidence interval, 0.59-0.81 for interquartile difference) were independent predictors of outcome. The SRI increased the prognostic power of the model on top of clinical and exercise testing variables (concordance index, + 10%; discrimination index, + 32%) and showed the widest area under the ROC curve to predict outcome as compared with exercise-only ST analysis and the ST/HR index. Moreover, it provided a significant discrimination of survival.

CONCLUSIONS

The SRI predicts all-cause mortality in hypertensive patients with chest pain and provides additional prognostic information over clinical and standard exercise testing data.

Advantages of exercise echocardiography in comparison to dobutamine echocardiography in the diagnosis of coronary artery disease in hypertensive subjects

OBJECTIVE

The aim of the study was to compare the efficacy and safety of two stress echocardiography methods, exercise and dobutamine, in the diagnosis of coronary artery disease in hypertensive patients with angina.

PATIENTS AND METHODS

A total of 197 treated hypertensive patients, age 53 +/- 9 years (65 women) with no history of myocardial infarction referred for coronary angiography were prospectively investigated with exercise electrocardiography (ECG), exercise and dobutamine echocardiography.

RESULTS

Sensitivity of the exercise ECG, exercise echocardiography and dobutamine echocardiography did not differ (77%, 82% and 75%). Negative predictive value of exercise ECG was significantly lower than exercise echocardiography (64% vs 79%, P < 0.01). Specificity and positive predictive value of exercise ECG were markedly lower than exercise and dobutamine echocardiography (57%, 96%, 98% and 72%, 97%, 98%, P < 0.0001 for both stress echocardiography vs ECG). Specificity and sensitivity of diagnostic methods were not influenced by the presence of echocardiographic left ventricular hypertrophy. Dobutamine infusion in comparison to exercise was more often associated with substantial arterial blood pressure rise or fall (7% vs 2%, P < 0.05) and with simple ventricular ectopy (15,7% vs 6,1%, P < 0.05).

CONCLUSIONS

In hypertensive patients with the symptoms of angina, both stress echo methods are significantly more specific than the exercise ECG test. Maximal exercise is associated with less frequent side effects than infusion of dobutamine, so exercise echocardiography may be preferred in the diagnosis of angina in hypertensive patients.

Diagnosis of myocardial ischemia in hypertensive patients

Arterial hypertension can provoke a reduction in coronary flow reserve through several mechanisms that are not mutually exclusive (i.e. epicardial coronary artery disease (CAD), left ventricular hypertrophy and structural and/or functional microvascular disease). These different targets of arterial hypertension should be explored with different diagnostic markers. In fact, stress-induced wall motion abnormalities are highly specific for angiographically assessed epicardial CAD, whereas ST segment depression and/or myocardial perfusion abnormalities are frequently found with angiographically normal coronary arteries associated with left ventricular hypertrophy and/or microvascular disease. Exercise-electrocardiography stress test can be used to screen patients with negative maximal test due to its excellent negative predictive value, which is high and comparable in normotensives and hypertensives. When exercise-electrocardiography stress test is positive (or uninterpretable or ambiguous), an imaging stress-echo test is warranted for a reliable identification of significant, prognostically malignant epicardial CAD in view of an ischemia-guided revascularization.

Safety, feasibility, and prognostic implications of pharmacologic stress echocardiography in 1482 patients evaluated in an ambulatory setting

BACKGROUND

The outpatient prognostic assessment of coronary artery disease (CAD) by exercise electrocardiography has limitations, including the feasibility of the test and its low positive predictive value in several clinical conditions. In the current study we investigated the safety, feasibility, and prognostic value of pharmacologic stress echocardiography in a large cohort of ambulatory patients.

METHODS

The study group was made of 1482 ambulatory patients (969 men, aged 60 +/- 10 years) who underwent stress echocardiography with either dipyridamole (n = 846) or dobutamine (n = 636) for evaluation of suspected or known stable CAD. The pretest likelihood of CAD was intermediate (<70%) in 709 patients and high (> or =70%) in 773 patients.

RESULTS

There was no complication during the dipyridamole test, whereas 2 ischemia-dependent, sustained ventricular tachycardias occurred during the dobutamine test. Limiting side effects were observed in 2% of dipyridamole and in 3% of dobutamine stresses. The echocardiogram was positive in 459 patients. During a mean follow-up of 28 +/- 24 months, 58 patients died, 33 had a nonfatal myocardial infarction, and 158 underwent early (< or =3 months) and 64 late (>3 months) revascularization. Multivariate predictors of hard events (death, infarction) were positive echocardiographic results (hazard ratio [HR] 2.9) and resting wall motion score index (WMSI) (HR 2.3). In considering major events (death, infarction, late revascularization) as end points, positive echocardiographic result (HR 4.3), scar (HR 2.2), and resting WMSI (HR 1.7) were independent prognostic predictors. The 5-year survival rates for the ischemic and nonischemic groups were, respectively, 80% and 91% (HR 3.6, 95% confidence interval [CI] 3.8-8.4; P <.0001) considering hard cardiac events and 65% and 88% (HR 2.6, 95% CI 2.1-5.9; P <.0001) considering major events. Multivariate predictors of major events were positive echocardiographic results (HR 8.2) and male sex (HR 2.5) for the intermediate-risk group and positive echocardiographic results (HR 2.9), resting WMSI (HR 1.8), and prior Q-wave myocardial infarction (HR 1.8) for the high-risk group.

CONCLUSIONS

Pharmacologic stress echocardiography is safe, highly feasible, and effective in prognostic assessment of ambulatory patients when both a general population and groups selected on the basis of pretest likelihood of CAD are analyzed. It represents a valid complementary tool to exercise electrocardiography for prognostic purposes in outpatients.

Dipyridamole-atropine stress echocardiography versus exercise SPECT scintigraphy for detection of coronary artery disease in hypertensives with positive exercise test

OBJECTIVES

Many different stress echocardiographic and radionuclide perfusion imaging tests have been proposed for detecting epicardial coronary artery disease (CAD) in hypertensive patients. Their relative diagnostic and prognostic value has not been exactly established.

BACKGROUND

A positive exercise electrocardiography test has a low diagnostic specificity in hypertensive patients and warrants for a complementary imaging test to confirm the diagnosis of coronary artery disease.

METHODS

Hypertensive patients (n = 53), (29 males, aged 58 +/- 10 years) with normal left ventricular function detected by echocardiography and previous positive exercise test ( > or = 0.15 mV of ST segment depression on 12 lead electrocardiogram) underwent dipyridamole-atropine stress echocardiography (DASE) and thallium-201 stress/ rest myocardial single-photon emission computed tomography (SPECT). All patients had coronary angiography within 15 days and independently of imaging test results.

RESULTS

Coronary angiogram showed significant ( > or = 50% qualitatively assessed diameter reduction) epicardial coronary artery disease in 23 (43%) patients. Sensitivity for detection of coronary artery disease was significantly higher for scintigraphy (DASE = 78% versus SPECT = 100%, P < 0.05) while specificity was higher for echo (DASE = 100% versus SPECT = 47%, P < 0.00001). Diagnostic accuracy was also higher for echo (DASE = 91% versus SPECT = 70%, P < 0.01).

CONCLUSION

In patients with exercise-nduced ST segment depression, dipyridamole stress echo and SPECT perfusion scintigraphy are both good diagnostic options, with DASE characterized by higher specificity, lower sensitivity, and at least comparable diagnostic accuracy than SPECT.

Is rest or exercise hypertension a cause of a false-positive exercise test?

STUDY OBJECTIVES

To determine if a history of hypertension or an exaggerated rise in exercise systolic BP is associated with a false-positive exercise ECG.

DESIGN, SETTING, AND PATIENTS

Retrospective analysis of the associations between exercise-induced ST-segment depression and a history of hypertension, exercise systolic BP, and several other clinical and exercise test variables. Among 20,097 patients referred for exercise tomographic thallium imaging in a nuclear cardiology laboratory at a tertiary care center, 1,873 patients met inclusion criteria for this study, which included no history of myocardial infarction or coronary artery revascularization, a normal resting ECG, and normal exercise thallium images.

RESULTS

False-positive ST-segment depression occurred in 20% of the population. A history of hypertension was actually associated with a lower likelihood of ST-segment depression (odds ratio, 0.70; 95% confidence interval [CI], 0.55 to 0.89; p = 0. 004). A higher peak exercise systolic BP was associated with a higher likelihood of ST-segment depression (odds ratio, 1.08 for each 10-mm Hg increase in systolic BP; 95% CI, 1.03 to 1.14; p < 0. 001). However, the association between peak exercise systolic BP and ST-segment depression was so weak that this measurement could not be predictive in the individual patient (R(2) = 0.2%). For every 20-mm Hg increase in peak exercise systolic BP, the percentage of patients with ST-segment depression increased by only 3%.

CONCLUSIONS

In patients with normal resting ECGs, we conclude the following: (1) a history of hypertension is not a cause of a false-positive exercise test, and (2) higher exercise systolic BP is a significant but weak predictor of ST-segment depression.

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

OBJECTIVE

Myocardial perfusion abnormalities may occur in hypertensive patients in absence of significant coronary artery disease. However, it is not well established whether hypertensive patients without known coronary artery disease have a higher prevalence or extent of myocardial perfusion abnormalities compared with normotensive patients with similar clinical features.

DESIGN

This study compares the prevalence and extent of rest and stress-induced myocardial perfusion abnormalities in patients with and without hypertension.

METHODS

Dobutamine (up to 40 microg/kg per min) stress technetium-99m myocardial perfusion SPECT imaging was performed for evaluation of myocardial ischaemia in 350 patients (mean age = 60+/-13 years, 146 men) without known coronary artery disease. One hundred and forty-eight patients were hypertensive. Rest SPECT images were acquired 24 h after the test Abnormal perfusion was defined as the presence of reversible or fixed perfusion defects.

RESULTS

No significant difference was detected between patients with and without hypertension regarding gender, prevalence of symptoms, risk factors, pretest probability of coronary artery disease (52+/-28 versus 53+/-29%), peak rate pressure product (21040+/-4755 versus 20774+/-4865) or number of patients achieving the target heart rate during stress (85 versus 86%). Hypertensive patients were significantly older (62+/-11 versus 58+/-13 years, P = 0.005) and were receiving beta-blockers more frequently (34 versus 18%, P = 0.0001). The prevalence of myocardial perfusion abnormalities was similar in patients with and without hypertension (28 versus 31% in patients with low, 38 versus 33% in patients with intermediate and 60 versus 58% in patients with high pretest probability of coronary artery disease, respectively). No significant difference was detected between the two groups regarding stress perfusion defect score (1.45+/-2.5 versus 1.50+/-2.6) or rest score (0.72+/-1.8 versus 0.68+/-1.6).

CONCLUSION

Treated hypertensive patients without known coronary artery disease have a similar prevalence and severity of myocardial perfusion abnormalities at rest and at dobutamine stress compared with normotensive patients with similar clinical characteristics.

Comparison of stress/rest myocardial perfusion tomography, dipyridamole and dobutamine stress echocardiography for the detection of coronary disease in hypertensive patients with chest pain and positive exercise test

OBJECTIVES

Although different noninvasive tests have been proposed for detecting coronary artery disease (CAD) in patients with hypertension and chest pain symptoms, the relative performance of the available techniques has not been systematically assessed.

BACKGROUND

Patients with hypertension frequently complain of chest pain and exhibit ischemic-like ST segment changes on the exercise electrocardiogram (ECG). However, the specificity of such changes for predicting significant CAD is very low, because these patients often exhibit a normal coronary angiogram.

METHODS

In 101 patients with hypertension, chest pain and positive exercise ECG, we performed stress/rest myocardial single photon emission computed tomography with 99mTc-MIBI, dipyridamole and dobutamine stress echocardiography and coronary angiography. All patients had normal global ventricular function and 57 had left ventricular hypertrophy. All were kept on ACE inhibitors during the study period.

RESULTS

No patients had significant side effects during perfusion scintigraphy. Dose-limiting side effects were observed in five patients with dipyridamole and in seven patients with dobutamine. Only 56% of study patients exhibited significant CAD. Sensitivity, specificity, accuracy, positive and negative predictive values were, respectively, 98%, 36%, 71%, 67% and 94% for perfusion scintigraphy, 61%, 91%, 74%, 90% and 64% for dipyridamole and 88%, 80%, 84%, 85% and 83% for dobutamine stress echocardiography.

CONCLUSIONS

This study shows that stress echo in patients with hypertension yields a satisfactory diagnostic accuracy for identifying significant epicardial CAD. Our results indicate that dobutamine might be superior to dipyridamole. The low specificity of myocardial scintigraphy probably relates to the fact that this method traces perfusion abnormalities, not necessarily caused by epicardial CAD, possibly due to microvascular disease and not causing obvious wall motion abnormalities.

Relation of exercise-induced myocardial ischemia to cardiac and carotid structure

There is a strong relation of carotid atherosclerosis to coronary artery disease and left ventricular hypertrophy. In addition, abnormalities of carotid structure are strongly associated with abnormal left ventricular geometry and structure. However, little is known regarding the relation of exercise-induced ST depression to carotid atherosclerosis, carotid, or left ventricular structure in the absence of apparent coronary disease. The relationship of exercise ECG myocardial ischemia to the presence of carotid atherosclerosis and to carotid and left ventricular structure was assessed in 204 asymptomatic subjects free of clinical evidence of cardiovascular disease. Myocardial ischemia on the exercise ECG, defined by a chronotropically adjusted ST/HR slope of >3.47 microV/bpm, was associated with a nearly threefold greater likelihood of discrete carotid atherosclerosis (50% [6 of 12] versus 17% [29 of 192], P=.007) and with older age, male sex, higher systolic and diastolic blood pressures, greater left ventricular mass and mass index, and greater common carotid artery intimal-medial thickness and cross-sectional area index. Stepwise logistic regression analyses, including standard risk factors, revealed that only carotid artery cross-sectional area index (P=.0007) and systolic blood pressure (P=.005) independently predicted an abnormal chronotropically adjusted ST/heart rate slope. Moreover, among 132 subjects with > or = 10 microV of ST-segment depression, only left ventricular mass index and carotid artery cross-sectional area index were significant predictors of the chronotropically adjusted ST/heart rate slope response. Subendocardial ischemia on the exercise ECG is strongly associated with the presence of carotid atherosclerosis and is related to systolic blood pressure, carotid artery cross-sectional area index, and left ventricular mass index, independent of age, sex, and other cardiac risk factors. These findings provide additional insights into the relation between coronary and carotid atherosclerosis and suggest that an association among ischemia and left ventricular and carotid structural abnormalities may contribute to the pathogenesis of coronary events.

Technetium-99m sestamibi myocardial tomography based on dipyridamole echocardiography testing in hypertensive patients with chest pain

The non-invasive diagnosis of coronary artery disease in hypertensives with chest pain is an important clinical concern because all exercise-dependent tests display limited feasibility and diagnostic accuracy; by contrast, dipyridamole echocardiography testing has been shown to have a similar feasibility and accuracy in hypertensive and normotensive subjects. The aim of this study was to evaluate the diagnostic capability of technetium-99m sestamibi tomography based on dipyridamole echocardiography testing in hypertensives with chest pain, and to compare the scintigraphic results with those of coronary angiography, exercise electrocardiography and dipyridamole echocardiography. Forty subjects with mild to moderate hypertension, chest pain and no previous myocardial infarction were submitted to 99mTc-sestamibi tomography (at rest and after high-dose dipyridamole echocardiography) and to exercise electrocardiography testing. At coronary angiography 22 patients (group A) had significant epicardial coronary artery disease (>/=70% stenosis of at least one major vessel) and 18 normal main coronary vessels (group B). Dipyridamole 99mTc-sestamibi imaging was positive in 21/22 patients of group A and in 5/18 of group B. Dipyridamole echocardiography was positive in 18/22 patients of group A and in 5/18 of group B. Exercise electrocardiography was positive in 15/22 patients of group A and in 11/18 of group B. Four out of five subjects in group B with positive results in all the tests showed a slow run-off of angiographic contrast medium, probably due to small-vessel disease. Significant epicardial coronary artery disease in hypertensives with chest pain is unlikely when dipyridamole 99mTc-sestamibi tomography is negative. When scintigraphy is positive, either epicardial coronary artery disease or a small-vessel disease condition is possible. The association of scintigraphy with dipyridamole echocardiography testing allows the assessment of contractile function and myocardial perfusion by a single pharmacological stress.

Influence of left ventricular hypertrophy on detection of coronary artery disease using exercise echocardiography

OBJECTIVES

This study examined the influence of left ventricular hypertrophy on the accuracy of exercise electrocardiography and echocardiography for detection of coronary artery disease.

BACKGROUND

Electrocardiographic repolarization abnormalities caused by left ventricular hypertrophy compromise the diagnostic accuracy of exercise electrocardiography but not of exercise echocardiography. The relative merits of these investigations are less well defined in patients with hypertrophy but without electrocardiographic (ECG) changes.

METHODS

We prospectively evaluated 147 consecutive patients without prior myocardial infarction undergoing both exercise echocardiography and coronary arteriography. Coronary stenoses > 50% diameter were present in 62 patients (42%). Positive test results were defined by a new or worsening wall motion abnormality or > 0.1 mV of ST depression. Echocardiographic left ventricular hypertrophy (mass > 131 g/m2 in men, > 100 g/m2 in women) was identified in 68 patients. A subgroup with clinically suspected hypertrophy was defined according to the presence of ECG evidence of hypertrophy, hypertension or aortic stenosis.

RESULTS

The overall sensitivity of exercise echocardiography exceeded that of exercise electrocardiography (71% vs. 54%, p = 0.06). Echocardiographic hypertrophy had no significant effect on the sensitivity of either test. The specificity of exercise echocardiography exceeded that of exercise electrocardiography (91 vs. 74%, p = 0.01). In patients with hypertrophy, the specificity of exercise echocardiography exceeded that of exercise electrocardiography (95% vs. 69%, p < 0.01), whereas among patients without hypertrophy, the specificities (respectively, 87% and 78%) were more comparable. The accuracy of exercise echocardiography exceeded that of the exercise ECG in the overall group (82% vs. 65%, p = 0.002) and in patients with hypertrophy (85% vs. 60%, p = 0.004), but this difference was less prominent in patients without hypertrophy (80% vs. 69%, p = NS). In patients with clinically suspected hypertrophy, exercise echocardiography demonstrated a higher sensitivity, specificity and accuracy than exercise electrocardiography. The cost incurred in the identification of coronary disease was least with a strategy involving use of the exercise echocardiogram instead of routine exercise testing in patients with known or clinically suspected left ventricular hypertrophy.

CONCLUSIONS

Exercise echocardiography is more accurate than exercise electrocardiography for the detection of coronary artery disease in patients with known or clinically suspected left ventricular hypertrophy.

Scintigraphic and electrocardiographic evidence of silent coronary artery disease in asymptomatic hypertension: a case-control study

OBJECTIVES

This study was conducted to determine the incidence of physiologically significant coronary artery disease in a group of asymptomatic high risk men with essential hypertension and to assess the validity of noninvasive tests in a subset of these patients undergoing coronary arteriography.

METHODS

Two hundred twenty-six asymptomatic men (mean age 61 +/- 8 years) with essential hypertension and no clinical evidence of coronary artery disease but with at least one additional coronary risk factor were studied prospectively. Fifty age- and risk factor-matched normotensive subjects were evaluated as a control group. After a minimum of 4 days without medication, subjects underwent stress thallium-201 scintigraphy, exercise and 48-h ambulatory electrocardiography, and echocardiography. Coronary angiography was performed in a subset of 34 (40%) of 84 patients with one or more positive test results.

RESULTS

A positive thallium-201 scintigram (18% vs. 6%; odds ratio 3.4, confidence interval 0.95 to 10.8, p = 0.056), exercise electrocardiograms (ECGs) (37% vs. 13%; odds ratio 4.1, confidence interval 1.5 to 11.2, p < 0.003) and ambulatory ECG (15% vs. 0%, p < 0.05) were more common in the hypertensive group than in the control group. In the cohort undergoing coronary angiography, thallium-201 scintigraphy was both sensitive and specific for epicardial atherosclerotic coronary disease (90% and 79%, respectively), but positive exercise and ambulatory ECGs occurred frequently in the absence of significant coronary stenoses. In the 39% of hypertensive patients who had mild to moderate left ventricular hypertrophy, positive exercise and ambulatory ECGs occurred at a higher rate.

CONCLUSIONS

These findings suggest that physiologically significant coronary artery disease occurs more frequently in asymptomatic hypertensive men than in comparable normotensive control subjects. In the subgroup undergoing coronary arteriography, reversible scintigraphic defects were both sensitive and specific for diagnosing epicardial coronary artery disease, but exercise and ambulatory ECGs appeared to yield frequent false positive results, especially when left ventricular hypertrophy was present. These results indicate that patients with "silent" coronary artery disease can be identified among high risk hypertensive patients, but the appropriate application of such screening in clinical practice remains to be determined.

Assessment of electrocardiographic ischemia in hypertensive patients treated with isradipine or placebo

A total of 203 patients with hypertension (supine diastolic blood pressure of 100-119 mm Hg) from six centers entered into a 3-week placebo baseline followed by 5 weeks of active treatment (either placebo or isradipine 2.5, 5, 7.5, or 10 mg BID) to determine the effectiveness of isradipine on blood pressure control. Electrocardiographic criteria for left-ventricular ischemia were coded blindly using the Minnesota Codes 4-1 to 4-4 and 5-1 to 5-3 at the end of baseline and active treatment periods. One hundred seventy patients with hypertension and matching and complete electrocardiograms completed the study for analysis: 63 (37%) were white and 117 (69%) were men. They were 52.1 +/- 10.3 years old mean +/- SD; range: 22-77 years). No myocardial infarction occurred during the active phase. Fifty-eight of 170 (34%) at baseline and 54 of 116 (32%) at week 5 had left atrial enlargement. Romhilt-Estes left-ventricular hypertrophy was not significantly different at baseline versus active treatment: 14 of 170 (8.2%) versus 15 of 170 (8.8%). At baseline, the rate of active ischemia was 28.2% (48/170): 27.8% (10/36) were randomized to receive placebo during active treatment and 28.4% (38/134) were given isradipine (P = NS). For those without ischemia at baseline, the rate of change to electrocardiographic ischemia during active treatment was 0% (0/26) for those receiving placebo and 3.1% (3/96) for those taking isradipine (P = NS). For those with ischemia at baseline, the rate of change to no ischemia during active treatment was 20% (2/10) for those receiving placebo and 10.5% (4/38) for those taking isradipine (P = NS).(ABSTRACT TRUNCATED AT 250 WORDS)

Hypertensive heart disease: relationship of silent ischemia to coronary artery disease and left ventricular hypertrophy

ECG evidence of silent ischemia occurs commonly in patients with systemic hypertension, but its relationship to left ventricular hypertrophy (LVH), large-vessel coronary artery disease (CAD), and neurohumoral factors remains unclear. Accordingly we validated the results of the echocardiographic method used to measure left ventricular (LV) mass in the Soviet Union by comparison with necropsy measurements in 30 patients, and we examined the relationships in 46 men with essential hypertension among ST segment depression during ambulatory monitoring, exercise stress and transesophageal pacing (n = 38), and LV mass, catheterization evidence of CAD (n = 25), and neurohumoral factors (plasma catecholamines and platelet aggregability). Echocardiographic measurements of LV mass by both the Soviet and Penn methods were closely correlated with necropsy values (r = 0.78 and 90, respectively; both p less than 0.001). During ambulatory monitoring from 1 to 17 episodes of greater than or equal to 1 mm ST depression occurred in 26 of 46 (65%) patients with hypertension; ischemia was also provoked by exercise or pacing stress in most but not all of these patients (65% and 80%, respectively). Neither ST depression nor the occurrence of additional episodes of symptomatic angina was related to the presence of coronary obstruction at catheterization; patients with and without ST depression did not differ in age, blood pressure, or LV mass.(ABSTRACT TRUNCATED AT 250 WORDS)

How can we diagnose coronary heart disease in hypertensive patients?

Chest pain is a common complaint among hypertensive patients. Hypertension and coronary heart disease each may present with symptoms and signs that are clinically indistinguishable. Noninvasive testing by routine exercise stress testing and stress radionuclide angiography are not reliably predictive of ischemia resulting from obstructive epicardial coronary artery disease and should be abandoned for that diagnostic purpose. Noninvasive thallium-201 myocardial perfusion imaging for this purpose may prove to be a valuable tool, avoiding the risk and expense of coronary arteriography. However, carefully performed prospective studies are not available. Because of the high prevalence of both diseases, a high priority must be given to obtaining these data and evaluating other noninvasive methods (especially positron emission tomography) if they appear promising.