Prediction of outcomes in hypertensive patients with suspected coronary disease

[The Clinical use of Stress Echocardiography in Ischemic Heart Disease Cardiovascular Ultrasound (2017)15:7. Translation authors: Arystan A.Zh., Fettser D.V.]

Stress echocardiography is an established technique for the assessment of extent and severity of coronary artery disease. The combination of echocardiography with a physical, pharmacological or electrical stress allows detecting myocardial ischemia with an excellent accuracy. A transient worsening of regional function during stress is the hallmark of inducible ischemia. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging or magnetic resonance, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician. The evidence on its clinical impact has been collected over 35 years, based on solid experimental, pathophysiological, technological and clinical foundations. There is the need to implement the combination of wall motion and coronary flow reserve, assessed in the left anterior descending artery, into a single test. The improvement of technology and in imaging quality will make this approach more and more feasible. The future issues in stress echo will be the possibility of obtaining quantitative information translating the current qualitative assessment of regional wall motion into a number. The next challenge for stress echocardiography is to overcome its main weaknesses: dependence on operator expertise, the lack of outcome data (a widespread problem in clinical imaging) to document the improvement of patient outcomes. This paper summarizes the main indications for the clinical applications of stress echocardiography to ischemic heart disease.

The clinical use of stress echocardiography in ischemic heart disease

Stress echocardiography is an established technique for the assessment of extent and severity of coronary artery disease. The combination of echocardiography with a physical, pharmacological or electrical stress allows to detect myocardial ischemia with an excellent accuracy. A transient worsening of regional function during stress is the hallmark of inducible ischemia. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging or magnetic resonance, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician.

The evidence on its clinical impact has been collected over 35 years, based on solid experimental, pathophysiological, technological and clinical foundations. There is the need to implement the combination of wall motion and coronary flow reserve, assessed in the left anterior descending artery, into a single test. The improvement of technology and in imaging quality will make this approach more and more feasible. The future issues in stress echo will be the possibility of obtaining quantitative information translating the current qualitative assessment of regional wall motion into a number. The next challenge for stress echocardiography is to overcome its main weaknesses: dependance on operator expertise, the lack of outcome data (a widesperad problem in clinical imaging) to document the improvement of patient outcomes. This paper summarizes the main indications for the clinical applications of stress echocardiography to ischemic heart disease.

Treadmill exercise echocardiography as a predictor of events in patients with left ventricular hypertrophy

BACKGROUND

Exercise echocardiography (EE) is recommended for patients with known/suspected coronary artery disease (CAD) and electrocardiogram (ECG) abnormalities. Left ventricular hypertrophy (LVH) is associated with worse outcome and patients with LVH have frequently resting ECG abnormalities. We sought to assess the value of EE for predicting outcome in patients with known/suspected CAD and LVH.

METHODS

Retrospective analysis over 1,058 patients, classified according to the presence (n = 557) or absence (n = 501) of LVH (LV mass > or =163 g for women, > or =225 g for men) who underwent EE. Wall motion score index (WMSI) was evaluated at rest and with exercise. Ischemia was defined as the development of new or worsening wall motion abnormalities (WMA) with exercise. The endpoints were all-cause mortality and major cardiac events (MACE). Overall, 352 patients (33%) developed new/worsening WMA.

RESULTS

During a follow-up of 4.6 +/- 4.0 years, 178 patients died and 129 had a MACE. The 5-year mortality and MACE rates were 6.4 and 7.1% in patients without ischemia vs. 15.3 and 13.6% in those with ischemia, respectively (P < 0.001). In the multivariable analysis, LV mass (hazard ratio (HR) 1.03, 95% confidence interval (CI) 1.02-1.04, P = 0.008) and DeltaWMSI (HR 1.94, 95% CI 1.12-3.35, P = 0.02) were independent predictors of mortality. DeltaWMSI was also an independent predictor of MACE in the overall population (P = 0.002) and in patients with LVH (P = 0.04).

CONCLUSION

LV mass independently predicts mortality, even when EE data are considered. EE provides significant information for predicting events in patients with LVH and known/suspected CAD.

Customized exercise echocardiography: beyond detection of coronary artery disease

Exercise echocardiography has been established as a reliable diagnostic tool for assessment of myocardial ischemia. However, more recent advances in its technique have expanded its routine clinical use to include quantification of exercise-induced diastolic dysfunction, exercise-induced pulmonary hypertension, and dynamic assessment of mitral and aortic valve function. The indications for exercise echocardiography have increased to include cardiac symptoms such as exertional dyspnea, fatigue, and limited exercise capacity. In light of its expanded capability for evaluating cardiovascular function, we believe that exercise echocardiography should be utilized in a new paradigm of personalized cardiology, in which we regularly investigate individual patient symptoms for endpoints beyond critical myocardial ischemia, for example, exercise-induced pulmonary hypertension. We refer to this refocused use of exercise echocardiography as "customized exercise echocardiography." In this review article, we present current scientific evidence to support our proposed role and discuss the logistical requirements for proper test performance of customized exercise echocardiography.

Prognostic value of exercise echocardiography in patients with atrial fibrillation

AIMS

Non-invasive imaging techniques for the detection of coronary artery disease (CAD) may have technical problems in patients with atrial fibrillation (AF). Although the prognostic value of exercise echocardiography (ExEcho) has been well established in several subgroups of patients, it has not yet been specifically evaluated in these patients.

METHODS AND RESULTS

From a population of 8095 patients with known or suspected CAD referred for ExEcho, 419 had AF at the time of the tests. Ischaemia was defined as the development of new or worsening wall motion abnormalities with exercise. Endpoints were hard cardiac events (i.e. cardiac death or non-fatal myocardial infarction). Mean age was 68.4 +/- 8.5 years, and 256 patients (61.1%) were men. Ischaemia was detected in 92 patients (22%). Over a mean follow-up of 3.10 +/- 2.98 years, 59 hard cardiac events occurred. The 5-year hard cardiac event rate was 37.3% in patients with ischaemia, when compared with 14.5% in patients without ischaemia (P < 0.001). In multivariate analysis, ischaemia on ExEcho remained an independent predictor of hard cardiac events (hazard ratio 1.99, 95% confidence interval 1.06-3.74, P = 0.03), and also provided incremental value over clinical, resting echocardiographic and treadmill exercise data for the prediction of hard cardiac events (P = 0.04).

CONCLUSION

ExEcho provides significant prognostic information for predicting hard cardiac events in patients with AF.

Stress echocardiography in the district hospital setting: a cost-saving analysis

AIMS

Accurate and cost-effective techniques are required for investigating patients experiencing chest pain, given the significant workload this patient cohort represents. We determined the cost impact of stress echocardiography compared with myocardial perfusion scintigraphy and coronary angiography in the investigation of patients with chest pain deemed unsuitable for exercise treadmill testing.

METHODS AND RESULTS

A total of 200 patients with chest pain-with a low-intermediate probability of coronary artery disease-consecutively referred for stress echocardiography were recruited. Referring clinicians were asked which management strategy they would have chosen were the stress echocardiography service unavailable. The cost saving of stress echocardiography, an accuracy analysis, and adverse outcomes at 6 and 24 months follow-up were determined. The total cost attributable to the stress echocardiography service was Pound Sterling 58 368. If unavailable, 78 (39%) patients would have been referred for angiography and 122 (61%) for perfusion scintigraphy at a cost of Pound Sterling 56 316 and Pound Sterling 42 090, respectively, with a total cost of Pound Sterling 98 406. This represents a cost saving of Pound Sterling 40 038.

CONCLUSION

Stress echocardiography is a cost saving method for the investigation of chest pain in patients with low-intermediate risk of flow limiting coronary artery disease in the district hospital setting.

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.

Stress echocardiography expert consensus statement: European Association of Echocardiography (EAE) (a registered branch of the ESC)

Stress echocardiography is the combination of 2D echocardiography with a physical, pharmacological or electrical stress. The diagnostic end point for the detection of myocardial ischemia is the induction of a transient worsening in regional function during stress. Stress echocardiography provides similar diagnostic and prognostic accuracy as radionuclide stress perfusion imaging, but at a substantially lower cost, without environmental impact, and with no biohazards for the patient and the physician. Among different stresses of comparable diagnostic and prognostic accuracy, semisupine exercise is the most used, dobutamine the best test for viability, and dipyridamole the safest and simplest pharmacological stress and the most suitable for combined wall motion coronary flow reserve assessment. The additional clinical benefit of myocardial perfusion contrast echocardiography and myocardial velocity imaging has been inconsistent to date, whereas the potential of adding - coronary flow reserve evaluation of left anterior descending coronary artery by transthoracic Doppler echocardiography adds another potentially important dimension to stress echocardiography. New emerging fields of application taking advantage from the versatility of the technique are Doppler stress echo in valvular heart disease and in dilated cardiomyopathy. In spite of its dependence upon operator's training, stress echocardiography is today the best (most cost-effective and risk-effective) possible imaging choice to achieve the still elusive target of sustainable cardiac imaging in the field of noninvasive diagnosis of coronary artery disease.

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.

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.

Combined assessment of left ventricular perfusion and function by gated single-photon emission computed tomography for the risk stratification of high-risk hypertensive patients

OBJECTIVE

This study was aimed at verifying whether combined information on left ventricular perfusion and function by electrocardiogram-gated single-photon emission computed tomography (SPECT) retains its known prognostic value in patients with systemic hypertension.

METHODS

A total of 415 hypertensive patients underwent rest and stress (exercise in 278 and dipyridamole in 137) gated 99mTc-sestamibi SPECT and prospective follow-up for the composite endpoint of death and acute coronary syndrome. Patients undergoing revascularization were censored. The individual effect of clinical and stress imaging data on outcome was evaluated by Cox regression analysis. Model validation was performed using bootstrap methods 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 24 months, 12 cardiac deaths and 32 acute coronary syndromes occurred. After adjusting for the most significant covariates, age [hazard ratio (HR) 1.62, 95% confidence interval (CI) 1.02-2.57], diabetes (HR 7.51, 95% CI 1.61-35.2), summed stress score (HR 2.06, 95% CI 1.07-4), and peak end-systolic volume (HR 3.62, 95% CI 1.35-9.69) were multivariable predictors of outcome. The normal perfusion pattern was associated with a low event rate independently of peak end-systolic volume. Conversely, in the case of moderate to severe perfusion abnormalities, a peak end-systolic volume greater than 74 ml was able to identify an increased risk of adverse outcome. Moreover, peak end-systolic volume was significantly higher among patients who died of a cardiac cause compared with those with different outcomes.

CONCLUSION

A combined assessment of left ventricular perfusion and function by gated SPECT significantly improves risk stratification in hypertensive patients.

The use of stress echocardiography for prognostication in coronary artery disease: an overview

PURPOSE OF REVIEW

Stress echocardiography has a high accuracy for the detection of coronary artery disease. Additionally, it provides clinically useful prognostic information, such as resting left ventricular function, myocardial viability, stress-induced ischemia, vascular extent of wall motion abnormalities, and changes in end-systolic volume and ejection fraction with stress.

RECENT DEVELOPMENTS

The timing, extent, and severity of the stress-induced wall motion abnormalities are important determinants of long-term prognosis. Previous studies have shown the efficacy of stress echocardiography in predicting long-term cardiac events in mixed patient groups and the value of this test in selected patient subsets.

SUMMARY

This review attempts to define the role of stress echocardiography for prognostication in coronary artery disease, pointing out the ability of this technique to identify low-risk and high-risk subsets among patients with known or suspected coronary artery disease and thus guide patient management decisions.

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.

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.

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.

Clinical, exercise electrocardiographic, and pharmacologic stress echocardiographic findings for risk stratification of hypertensive patients with chest pain

Exercise electrocardiography (ECG) is of limited usefulness in hypertensive patients, whereas pharmacologic stress echocardiography can provide diagnostic and prognostic information. The aim of this study was to compare the prognostic value of clinical data, exercise ECG, and pharmacologic stress echocardiography in hypertensive patients with chest pain and to identify the best strategy for their risk stratification. Three hundred sixty-seven hypertensive patients (189 men, age 61 +/- 9 years) with chest pain of unknown origin underwent exercise ECG and pharmacologic stress echocardiography (237 with dipyridamole and 130 with dobutamine) and were followed up for 31 +/- 24 months. Positive exercise ECG (ST-segment shift of > or =1 mm at 80 ms after the J point) and stress echocardiography (new wall motion abnormalities) were found in 130 (35%) and 86 (23%) patients, respectively. During follow-up, there were 13 deaths and 16 myocardial infarctions. Additionally, 43 patients underwent coronary revascularization and were censored accordingly. Of 12 clinical, electrocardiographic, and echocardiographic variables analyzed, a positive result of stress echocardiography was the only multivariate predictor of either death (hazard ratio [HR] 4.7, 95% confidence interval [CI] 1.5 to 14.5, p = 0.007) or hard events (death, myocardial infarction) (HR 4.1, 95% CI 1.8 to 9.3, p = 0.0009). Using an interactive stepwise procedure, stress echocardiography provided additional prognostic information to clinical evaluation and exercise ECG. However, the negative predictive value of the 2 tests was similarly (p = NS) high in assessing 4-year event-free survival. In conclusion, a negative exercise electrocardiographic test identifies low-risk hypertensive patients with chest pain and should be the first-line approach for risk stratification. In contrast, positive exercise ECG is unable to distinguish between patients with different levels of risk. In this case, stress echocardiography provides strong and incremental prognostic power over clinical and exercise electrocardiographic data.