Prognostic importance of dipyridamole-echocardiography test in coronary artery disease

Comparison of the different anti-CD16 antibody clones in the activation and expansion of peripheral blood NK cells

Natural killer (NK) cells are promising tool for cancer treatment. Methods have been developed for large-scale NK cell expansion, including feeder cell-based methods or methods involving stimulation with NK cell activating signals, such as anti-CD16 antibodies. Different clones of anti-CD16 antibodies are available; however, a comprehensive comparison of their differential effects on inducing NK cell activation and expansion has not been conducted among these various clones under the same experimental conditions. Herein, we found that the NK cell expansion rate differed depending on the various anti-CD16 antibodies (CB16, 3G8, B73.1, and MEM-154) coated on microbeads when stimulated with genetically engineered feeder cells, K562‑membrane-bound IL‑18, and mbIL‑21 (K562‑mbIL‑18/-21). Only the CB16 clone combination caused enhanced NK cell expansion over K562‑mbIL‑18/-21 stimulation alone with similar NK cell functionality. Treatment with the CB16 clone once on the initial day of NK cell expansion was sufficient to maximize the combination effect. Overall, we developed a more enhanced NK expansion system by merging a feeder to effectively stimulate CD16 with the CB16 clone.

Apparent Declining Prognostic Value of a Negative Stress Echocardiography Based on Regional Wall Motion Abnormalities in Patients With Normal Resting Left Ventricular Function Due to the Changing Referral Profile of the Population Under Study

Background Cardiology guidelines identify the low-risk response during stress echocardiography as the absence of regional wall motion abnormalities. Methods From 1983 to 2016, we enrolled 5817 patients (age 63±12 years; 2830 males) with suspected coronary artery disease, normal regional, and global left ventricular function at rest and during stress (exercise in 692, dipyridamole in 4291, and dobutamine in 834). Based on timing of enrollment, 4 groups were identified in chronological order of recruitment: years 1983 to 1989, group 1 (n=211); years 1990 to 1999, group 2 (n=1491); years 2000 to 2009, group 3 (n=3285); and years 2010 to 2016, group 4 (n=830). Results There were 240 (4%) events (119 deaths and 121 infarctions) in the follow-up. At 1-year follow-up, the event rate was 0.5% (95% CI, 0.05-0.95), 1.5% (95% CI, -1.18 to 1.82), 1.9% (95% CI, 1.63-2.17), and 1.7% (95% CI, 1.01-2.39; χ², 9.0; P=0.03) in groups 1 to 4, respectively. At multivariable Cox analysis, independent predictors of future events were age (hazard ratio (HR), 1.05; 95% CI, 1.04-1.07; P<0.0001), male sex (HR, 1.57; 95% CI, 1.20-2.04; P=0.001), diabetes mellitus (HR, 1.78; 95% CI, 1.34-2.37; P<0.0001), smoking habit (HR, 1.40; 95% CI, 1.05-1.85; P=0.02), and ongoing anti-ischemic therapy (HR, 1.50; 95% CI, 1.15-1.97; P=0.003) Conclusions Over the past 3 decades, we observed a progressive decline in the prognostic value of a negative test based on regional wall motion abnormalities, likely reflecting both an increase in risk in patients, as well as a potential decrease in test performance due to concomitant anti-ischemic therapy.

[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.

Stress Echocardiography Positivity Predicts Cancer Death

BACKGROUND

Stress echocardiography (SE) predicts cardiac death, but an increasing share of cardiac patients eventually die of cancer. The aim of the study was to assess whether SE positivity predicts cancer death.

METHODS AND RESULTS

In a retrospective analysis of prospectively acquired single-center, observational data, we evaluated 4673 consecutive patients who underwent SE from 1983 to 2009. All patients were cancer-free at index SE and were followed up for a median of 131 months (interquartile range 134). We separately analyzed predetermined end points: cardiovascular, cancer, and noncardiovascular, noncancer death, with and without competing risk. SE was positive in 1757 and negative in 2916 patients; 869 cardiovascular, 418 cancer, and 625 noncardiovascular, noncancer deaths were registered. The 25-year mortality was higher in SE-positive than in SE-negative patients, considering cardiovascular (40% versus 31%; P<0.001) and cancer mortality (26% versus 17%; P<0.01). SE positivity was a strong predictor of cancer (cause-specific hazard ratio 1.19; 95% confidence interval, 1.16-1.73; P=0.05) and cardiovascular mortality (1.18; 95% confidence interval, 1.03-1.35; P=0.02). Fine-Gray analysis to account for competing risk gave similar results. Cancer risk diverged after 15 years, whereas differences were already significant at 5 years for cardiovascular risk.

CONCLUSIONS

SE results predict cardiovascular and cancer mortality. SE may act as a proxy of the shared risk factor milieu for cancer or cardiovascular death.

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.

Prognostic models in coronary artery disease: Cox and network approaches

Predictive assessment of the risk of developing cardiovascular diseases is usually provided by computational approaches centred on Cox models. The complex interdependence structure underlying clinical data patterns can limit the performance of Cox analysis and complicate the interpretation of results, thus calling for complementary and integrative methods. Prognostic models are proposed for studying the risk associated with patients with known or suspected coronary artery disease (CAD) undergoing vasodilator stress echocardiography, an established technique for CAD detection and prognostication. In order to complement standard Cox models, network inference is considered a possible solution to quantify the complex relationships between heterogeneous data categories. In particular, a mutual information network is designed to explore the paths linking patient-associated variables to endpoint events, to reveal prognostic factors and to identify the best possible predictors of death. Data from a prospective, multicentre, observational study are available from a previous study, based on 4313 patients (2532 men; 64±11 years) with known (n=1547) or suspected (n=2766) CAD, who underwent high-dose dipyridamole (0.84 mg kg(-1) over 6 min) stress echocardiography with coronary flow reserve (CFR) evaluation of left anterior descending (LAD) artery by Doppler. The overall mortality was the only endpoint analysed by Cox models. The estimated connectivity between clinical variables assigns a complementary value to the proposed network approach in relation to the established Cox model, for instance revealing connectivity paths. Depending on the use of multiple metrics, the constraints of regression analysis in measuring the association strength among clinical variables can be relaxed, and identification of communities and prognostic paths can be provided. On the basis of evidence from various model comparisons, we show in this CAD study that there may be characteristic factors involved in prognostic stratification whose complexity suggests an exploration beyond the analysis provided by the still fundamental Cox approach.

Stress echocardiography

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. In spite of its dependence upon operator's training, it is the best possible choice to achieve the still elusive target of sustainable cardiac imaging in the field of noninvasive diagnosis of coronary artery disease.

Trends of increasing medical radiation exposure in a population hospitalized for cardiovascular disease (1970-2009)

BACKGROUND

High radiation doses employed in cardiac imaging may increase cancer frequency in exposed patients after decades. The aim of this study was to evaluate the relative trends in medical radiation exposure in a population hospitalized for cardiovascular disease.

METHODS AND RESULTS

An observational single-center study was conducted to examine 16,431 consecutive patients with heart disease admitted to the Italian National Research Council Institute of Clinical Physiology between January 1970 and December 2009. In all patients, the cumulative estimated effective dose was obtained from data mining of electronic records of hospital admissions, adopting the effective dose typical values of the American Heart Association 2009 statement and Mettler's 2008 catalog of doses. Cumulative estimated effective dose per patient in the last 5 years was 22 (12-42) mSv (median, 25(th)-75(th) percentiles), with higher values in ischemic heart disease (IHD), 37 (20-59) vs non-IHD, 13 (8-22) mSv, p<0.001. Trends in radiation exposure showed a steady increase in IHD and a flat trend in non-IHD patients, with variation from 1970-74 to 2005-2009 of +155% for IHD (p<0.001) and -1% in non-IHD (NS). The relative contribution of different imaging techniques was remodeled over time, with nuclear cardiology dominating in 1970s (23% of individual exposure) and invasive fluoroscopy in the last decade (90% of individual exposure).

CONCLUSION

A progressive increase in cumulative estimated effective dose is observed in hospitalized IHD patients. The growing medical radiation exposure may encourage a more careful justification policy regarding ionizing imaging in cardiology patients applying the two main principles of radiation protection: appropriate justification for ordering and performing each procedure, and careful optimization of the radiation dose used during each procedure.

Downstream procedures and outcomes after stress testing for chest pain without known coronary artery disease in the United States

BACKGROUND

Millions of Americans with suspected coronary artery disease undergo noninvasive cardiac stress testing annually. Downstream procedures and subsequent outcomes among symptomatic patients without known coronary disease referred for stress testing are not well characterized in contemporary community practice.

METHODS

We examined administrative insurance billing data from a national insurance provider from November 2004 through June 2007. After excluding patients with prior cardiac disease or chest pain evaluation, we identified 80,676 people age 40 to 64 years with outpatient cardiac stress testing within 30 days after an office visit for chest pain. We evaluated rates of invasive coronary angiography, coronary revascularization, and cardiovascular events after stress testing.

RESULTS

Within 60 days, only 8.8% of stress test patients underwent cardiac catheterization and only 2.7% underwent revascularization; within 1 year, only 0.5% died and had myocardial infarction or stroke. There were marked geographic variations in 1-year rates of catheterization (3.8%-14.8%) and revascularization (1.2%-3.0%) across 20 hospital referral regions.

CONCLUSIONS

In this large national cohort of middle-aged patients without previously coded cardiac diagnosis who were referred for stress testing after outpatient chest pain evaluation, few proceeded to invasive angiography or revascularization, and subsequent cardiovascular events were infrequent.

Imaging techniques in coronary atherosclerotic disease: dobutamine stress echocardiography--evidence and perspectives

Dobutamine stress echocardiography is the most widely disseminated noninvasive technique for the assessment of coronary artery disease. Its results are important for clinical decisions. It is a versatile technique with high sensitivity and specificity for detecting viable myocardium at jeopardy. More recently, strain rate imaging has been applied to stress echocardiography. This approach relies on tissue Doppler or two-dimensional strain imaging to quantify myocardial deformation. The application of contrast echocardiographic techniques to stress echocardiography enables left ventricular opacification for border enhancement and myocardial perfusion imaging. Thus, this application is not limited to stress echocardiography, but has utility whenever image quality adversely affects wall motion assessment. Recently, three-dimensional stress echocardiography imaging has been proposed as an alternative approach to assess myocardial ischemia.

Stress echocardiography as a gatekeeper to donation in aged marginal donor hearts: anatomic and pathologic correlations of abnormal stress echocardiography results

BACKGROUND

Owing to the shortage of donor hearts, the criteria for acceptance have been considerably expanded. Pharmacologic stress echocardiography is highly accurate in identifying prognostically significant coronary artery disease, but brain death and catecholamine storm in potential heart donors may substantially alter the cardiovascular response to stress. This study assessed correlates of an abnormal resting/stress echocardiography results in potential donors.

METHODS

From April 2005 to December 2007, 18 marginal candidate donors (9 men) aged 58 +/- 5 years were initially enrolled. After legal declaration of brain death, all marginal donors underwent bedside echocardiography, with baseline and (when resting echocardiography was normal) dipyridamole (0.84 mg/kg in 6 min) or dobutamine (up to 40 microg/kg/min) stress echo. Non-eligible hearts (with abnormal rest or stress echo findings) were excluded and underwent cardioautoptic verification.

RESULTS

Resting echocardiography showed wall motion abnormalities in 5 patients (excluded from donation). Stress echocardiography was performed in the remaining 13 (dipyridamole in 11; dobutamine in 2). Results were normal in 7, of which 6 were uneventfully transplanted in marginal recipients. Results were abnormal in 6, and autoptic verification performed showed coronary artery disease in 5, and initial cardiomyopathy in 1.

CONCLUSIONS

Bedside pharmacologic stress echocardiography can safely be performed in candidate heart donors, is able to unmask occult coronary artery disease or cardiomyopathy, and shows potential to extend donor criteria in heart transplantation. Further experience with using marginal donors is needed before exact guidelines can be established.

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.

Short-term Risk Stratification with Accelerated High-dose Dipyridamole Stress Echocardiography: Follow-up into 301 Consecutive Outpatients

AIM

This study aimed to assess the short-term predictive value of a pharmacologic stress echocardiography test performed with accelerated high-dose dipyridamole (0.84 mg/kg over 6 minutes).

METHODS

In all, 301 patients (161 men, mean age 61.41 +/- 11.62 years) were scheduled for accelerated high-dose dipyridamole stress test. A total of 22 tests were interrupted prematurely because of side effects (overall feasibility 92.7%). The patients were followed up for nonfatal myocardial infarction, unstable angina, myocardial revascularization, and sudden death at first and third months and each 6 months (maximum 18 months).

RESULTS

A positive echocardiographic response was found in 25 patients. Six patients with negative stress test experienced events. Eight patients with positive stress test went to coronary revascularization procedure. Negative predictive value was 97.8%, positive predictive value was 32%, sensitivity was 57%, and specificity was 94%.

CONCLUSIONS

Risk stratification with accelerated high-dose dipyridamole stress echocardiography is effective. A negative test predicts favorable short-term cardiovascular prognosis.

Correlation between myocardial perfusion abnormalities detected with intermittent imaging using intravenous perfluorocarbon microbubbles and radioisotope imaging during high-dose dipyridamole stress echo

BACKGROUND

The clinical accuracy of myocardial contrast echocardiography (MCE) using intermittent harmonic imaging and intravenous perfluorocarbon containing microbubbles during dipyridamole stress has not been evaluated in a multicenter setting.

HYPOTHESIS

The accuracy of dipyridamole stress contrast echo in the detection of coronary artery disease (CAD) using myocardial perfusion images is high in comparison with technetium-99 (99Tc) sestamibi single-photon emission computed tomography (MIBI SPECT) and increases the accuracy of wall motion data.

METHODS

In 68 consecutive nonselected patients (46 men; mean age 66 years) from three different institutions in two countries. dipyridamole stress echo and SPECT with 99mTc MIBI were compared. Continuous intravenous (IV) infusion of perfluorocarbon exposed sonicated dextrose albumin (PESDA) (2-5 cc/min) was administered for baseline myocardial perfusion using triggered harmonic end systolic frames. Real-time digitized images were used for wall motion analysis. Dipyridamole was then injected in two steps: (1) 0.56 mg/kg for 3 min, (2) 0.28 mg/kg for 1 min, if the first step was negative for an inducible wall motion abnormality. After dipyridamole injection, myocardial contrast enhancement and wall motion were analyzed again by the same methodology.

RESULTS

There were 35 patients with perfusion defects by SPECT. Wall motion was abnormal in 22, while MCE was abnormal in 32. Wall motion and MCE each had one false positive. The proportion of correctly assigned patients was significantly better with MCE than with wall motion (p = 0.03; chi square test).

CONCLUSIONS

Myocardial contrast echocardiography, using intermittent harmonic imaging and intravenous perfluorocarbon containing microbubbles, is a very effective method for detecting coronary artery disease during dipyridamole stress echo.

A meta-analytic comparison of echocardiographic stressors

BACKGROUND

The relative performance of alternative stressors for stress echocardiography for the diagnosis of coronary artery disease (CAD) is not well established.

METHODS

All studies published between 1981 to December 2001 who met inclusion criteria were included in this analysis. We performed a summary receiver operator characteristic (SROC) analysis and calculated weighted mean of the likelihood ratio and sensitivity/specificity. A covariate analysis using meta-regression methods was also performed.

RESULTS

Forty-four studies presented data on Exercise, 11 on Adenosine, 80 on Dobutamine, 40 on Dipyridamole, 16 on transatrial pacing transesophageal echocardiography (Tap-TEE), and 7 on transatrial pacing transthorasic echocardiography (Tap-TTE). SROC analysis showed that the following order of most discriminatory to least: Tap-TEE, Exercise, Dipyridamole, Dobutamine and Adenosine. Weighted means sensitivity/specificity were Exercise: 82.6/84.4%, Adenosine: 68.4/80.9%, Dobutamine: 79.6/85.1%, Dipyridamole: 71.0/92.2%, Tap-TTE: 90.7/86.1%, and Tap-TEE: 86.2/91.3%. Covariate analysis showed that the discriminatory power of Exercise decreased with increasing mean age.

CONCLUSIONS

Tap-TEE is a very accurate test for both ruling in and ruling out CAD although its invasiveness may limit its clinical acceptability. Exercise is a well-balanced satisfactory test for both ruling in and ruling out but performance might be lower for the elderly. Dobutamine offers a reasonable compromise for Exercise. Dipyridamole might be good for ruling in but not for ruling out CAD. The incapability in ruling-out CAD was a major problem in clinical application of the stress. Adenosine was the least useful stressor in diagnosing CAD.

Long-term Prognostic Value of Transesophageal Atrial Pacing Stress Echocardiography

OBJECTIVE

The aim of our study was to evaluate the long-term prognostic value of transesophageal atrial pacing stress echocardiography (TAPSE) for the prediction of cardiovascular events (myocardial infarction) and mortality at 10-year follow-up.

METHODS

TAPSE was applied as a diagnostic modality in 93 consecutive patients (mean age 45 +/- 8 years) who were diagnosed for the cause of chest pain. Long-term follow-up data were obtained from 87 (94%) patients with a mean duration of follow-up of 92 +/- 4 months. Stress echocardiography was performed using TAPSE with a mean pacing rate of 142 +/- 18/min.

RESULTS

Predefined cardiac events occurred during the follow-up period in 45 (52%) patients, including 24 (28%) with hard end points: 10 (12%) with nonfatal myocardial infarction and 17 who died (events overlap). Positive result of TAPSE was found in 47 (54%) patients and among those with positive TAPSE result, 16 died (94% of total mortality) and 21 had a hard event (death or infarction-88% of total prevalence). Survival free from hard events was noted in 37 (92%) patients with negative TAPSE and only in 26 (55%) of those with positive TAPSE ( P = .001). Independent predictive factors for mortality were TAPSE positivity (relative risk with 95% confidence interval [RR/CI] = 39.6 [36.3-42.9], P = .0006) and diabetes (RR/CI = 10.2 [8.6-11.8], P = .0026). Independent predictive factors for myocardial infarction were diabetes (RR/CI = 8.1 [6.3-9.9], P = .0186) and significant coronary stenosis in angiography (RR/CI = 9.0 [6.8-11.2], P = .0479). Independent predictive factors for death or nonfatal myocardial infarction were TAPSE positivity (RR/CI = 12.3 [11.1-13.3], P = .0001) and diabetes (RR/CI = 7.0 [5.8-8.2], P = .0018).

CONCLUSIONS

Positive TAPSE result carries long-term prognostic information regarding mortality and risk of myocardial infarction that can be used to identify patients requiring more aggressive treatment. Negative TAPSE allows highly accurate definition of low-risk population with discriminating power maintained during the 10-year period. TAPSE result and diabetes are the strongest independent predictors for long-term mortality in multivariate analysis.

Diagnostic value of stress echocardiography for the detection of restenosis after PTCA

Stress echocardiography (SE) has become a widely accepted clinical tool for the non-invasive diagnosis of coronary artery disease (CAD). Previous studies have confirmed that SE has superior diagnostic value compared to exercise ECG testing. SE has also emerged as a cost-effective alternative to nuclear imaging techniques in patients where symptoms and/or conventional ECG stress testing have provided ambiguous results. Several studies have investigated the value of SE to detect significant restenosis after PTCA. However, in these studies, different methods have been used to induce cardiovascular stress such as physical exercise by bicycle or treadmill, pharmacologic stress testing (with dipyridamole or dobutamine) or transoesphageal atrial pacing. This review evaluates the published database of SE to detect restenosis in patients after successful PTCA. It includes 13 studies with a total of 989 patients performed at 3-6 months after the primary intervention. The diagnostic value, utility and limitations of SE is presented and discussed. The data show that SE has a high diagnostic value for detecting significant restenosis after PTCA. Mean sensitivity of SE was 74% (CI 69-79%), mean specificity was 87% (CI 84-89%). The positive predictive value (PPV) of SE was 83%, the overall negative predictive value (NPV) 97%. We conclude that, in the follow-up of patients after PTCA, SE has distinct advantages over other non-invasive methods and is a recommended method for the detection of those to be considered for repeat angiography.

Long-term prognostic importance of transient left ventricular dilation during pharmacologic stress echocardiography

OBJECTIVES

We sought to evaluate the prognostic significance of left ventricular (LV) transient ischemic dilation (TID) for patients with a positive stress echocardiogram (SE).

BACKGROUND

TID during SE has been related to the presence of extensive coronary artery disease, but its long-term prognostic implications have not been reported.

METHODS

In all, 99 consecutive patients with a positive SE comprised the study group. LV volumes were evaluated according to the modified Simpson's rule. TID during SE was defined as the presence of an increase in LV end-diastolic volume during the stress test. A clinical history was fulfilled for each patient and all of them were followed up.

RESULTS

Of 99 patients, 32 (32.3%) showed TID. Mean age was 65.8 +/- 9.8 years for non-TID group and 70.2 +/- 8.4 for TID group (P = .048). Baseline characteristics and subsequent treatment were similar in both groups. Mean follow-up was 21.4 +/- 15.8 months. In non-TID group the mean survival free of acute myocardial infarction was 47.28 months and 39.7 months in TID group (log rank = 0.012). In the univariate and multivariate analysis only TID and the wall motion score index were found as independent predictors related to long-term prognosis (risk ratio = 6.9; 95% confidence interval = 0.8-59.6; P = .042; and risk ratio = 0.4; 95% confidence interval = 0.18-0.89; P = .047, respectively).

CONCLUSIONS

LV TID during SE is an easy and independent prognostic marker. It helps to select patients with increased risk.

Pharmacologic stress echocardiography predicts total mortality early after acute myocardial infarction

OBJECTIVE

The aim of this multicenter, prospective, observational study was to assess the value of inducible ischemia in a large population of survivors of a first uncomplicated myocardial infarction (MI).

METHODS AND RESULTS

Pharmacologic stress echocardiography either with high-dose dipyridamole (0.84 mg/kg over 10 minutes) or high-dose dobutamine (up to 40 microg/kg over 3 minutes) (DET) was performed 9 +/- 10 days after a first acute uncomplicated MI in 1681 patients (1499 males; 57 +/- 10 years) with technically satisfactory rest echocardiographic study. Patients were followed up for a mean of 16 +/- 18 months (range: 1-122). DET was positive for myocardial ischemia in 884 (52.5%) and negative in 797 (47.5%) patients. During the follow-up there were 49 deaths for all-cause mortality (2.9% of the total population), 22 of which were cardiac; 62 (3.6%) nonfatal MIs; and 164 (9.7%) hospital readmissions for unstable angina. In all, 376 patients (22%) underwent coronary revascularization (bypass operation or angioplasty).

RESULTS

Hard events occurred in 71 of the 884 patients with positive and in 40 of the 797 patients with negative DET (8% vs 5%, P =.014). Using the Cox proportional hazards model, age (relative risk [RR] 1.07, 95% confidence interval [CI] 1.03-1.1), history of angina (RR 3.8, 95% CI 1.6-8.6), peak wall-motion score index (RR 2.2, 95% CI 1.1-4.4), and pharmacologic dose at ischemia (RR 1.5, 95% CI 1.04-2.3) were independent predictors of all-cause death.

CONCLUSIONS

In survivors of a first acute uncomplicated MI DET allows effective risk stratification on the basis of the presence, severity, and extent the induced ischemia.

Stress echocardiography for risk stratification of patients with chest pain and normal or slightly narrowed coronary arteries

One hundred twenty-five patients (60 +/- 10 years old, 60 women) with known (35, previous myocardial infarction) or suspected (90) coronary artery disease (CAD) and no more than 50% coronary stenoses underwent pharmacologic (48 dipyridamole and 77 dobutamine) stress echocardiography (SE) and prospective follow-up (36 +/- 22 months) for cardiac death, nonfatal infarction, and unstable angina. The ability of clinical and SE variables to predict the outcome was assessed by the Cox model. A significant increase in the global chi-square of the model indicated an incremental prognostic value. Nine events occurred: 2 fatal and 5 nonfatal infarctions and 2 hospitalizations for unstable angina. Hypertension, positive SE, and peak wall motion score index were multivariate predictors of outcome, but SE provided an 87.5% increase in the global chi-square (P <.001). Patients with positive SE had a significantly lower event-free survival compared with those with negative SE. Therefore, we conclude that SE provides incremental prognostic information in patients with chest pain without critical coronary artery disease.

Non-invasive prediction of angiographic progression of coronary artery disease by dipyridamole-stress echocardiography

BACKGROUND

Coronary angiography is the currently accepted standard means for assessing progression of coronary artery disease. A dipyridamole-echocardiography test (DET) might provide an alternative non-invasive functional imaging method for this purpose.

OBJECTIVE

To assess whether variations in results of serial DET match variations in angiographic assessments of coronary artery disease.

METHODS

From the Pisa Institute of Clinical Physiology stress-echocardiography data bank (1983-1998), we selected 60 patients satisfying the inclusion criteria of coronary angiography and DET having each been performed and interpreted twice independently and within 1 week. The second angiographic and stress-echocardiographic assessment was performed 45+/-31 months after the initial one. Angiographic progressors were defined a priori as patients with any progression of stenosis to occlusion and those with any stenosis > 30% with > 20% progression of stenosis measured by visual and quantitative coronary angiography. Stress-echocardiography progressors were defined as those patients who had previously had a negative test of a test having a positive result and those patients who had positive results of tests both in initial testing and in a second session of testing with the latter having a peak wall-motion-score index > 0.12 (on a scale of 1, normal to 4, dyskinetic in a 16-segment model) larger than the former.

RESULTS

Of the 60 patients, 44 were angiographic 'progressors' and 16 were 'non progressors'. Stress-echocardiographic responses were concordant with angiographic identification for 39 of 44 progressors and 15 of 16 non-progressors, with an overall concordance of 90%.

CONCLUSIONS

Measurement of dipyridamole-stress-echocardiographic response allows one to separate angiographic progressors and non-progressors efficiently, simply by taking into account the presence, extent and severity of stress-induced abnormalities of wall motion.

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.

Molecular Mechanism of Cardiac Hypertrophy and Development

Congestive heart failure is a major issues for cardiologists and to fully understand heart failure, it is important to understand the mechanism of the development of cardiac hypertrophy. Hemodynamic overload, namely mechanical stress, is a major cause of cardiac hypertrophy and to dissect the signaling pathways from mechanical stress to cardiac hypertrophy, an in-vitro device by which mechanical stress can be imposed on cardiac myocytes of neonatal rats cultured in serum-free conditions has been developed. Passively stretching cardiac myocytes cultured on silicone membranes induced various hypertrophic responses, such as activation of the phosphorylation cascades of many protein kinases, expression of specific genes and an increase in protein synthesis. During this process, secretion and production of vasoactive peptides, such as angiotensin II and endothelin-1, were increased and they played critical roles in the induction of these hypertrophic responses. Candidates for the 'mechanoreceptor' that receives the mechanical stress and converts it into intracellular biochemical signals have been recently demonstrated. Gene therapy and cell transplantation are hopeful strategies for the treatment of heart failure and require an understanding of how normal cardiac myocytes are differentiated. A key gene that plays a critical role in cardiac development has been isolated. The cardiac homeobox-containing gene Csx is expressed in the heart and the heart progenitor cells from the very early developmental stage, and targeted disruption of the murine Csx results in embryonic lethality because of the abnormal looping morphogenesis of the primary heart tube. With a cardiac zinc finger protein GATA4, Csx induces cardiomyocyte differentiation of teratocarcinoma cells as well as upregulation of cardiac genes. Mutations of human CSX cause various congenital heart diseases including atrial septal defect, ventricular septal defect, tricuspid valve abnormalities and atrioventricular block.

The influence of left ventricular geometry on coronary vasomotion in patients with essential hypertension

The objective of this study was to assess the influence of left ventricular (LV) geometric pattern on coronary vasomotion in patients with essential hypertension. We studied 34 hypertensive patients, who had never been treated, with angiographically normal coronary arteries. Patients were classified into four LV geometric patterns by echocardiography: normal, concentric remodeling, eccentric hypertrophy, and concentric hypertrophy. The responses of coronary vasomotion in left anterior descending artery to vasoactive agents (acetylcholine, isosorbide dinitrate, adenosine triphosphate) were examined using a Doppler guidewire and quantitative coronary angiography. The percent increase in coronary blood flow evoked with acetylcholine (endothelium-dependent vasomotion) showed lowest in concentric hypertrophy, followed by eccentric hypertrophy, concentric remodeling, and normal geometry. The significant linear relationship between acetylcholine-induced coronary blood flow and LV mass was noted. There was no difference in the percent increase in coronary blood flow evoked with isosorbide dinitrate (endothelium-independent vasomotion of conduit vessel) among the four groups. The percent increase in coronary blood flow evoked with adenosine triphosphate (endothelium-independent vasomotion of resistant vessel) was significantly lower in patients with concentric hypertrophy than in the other three groups. The results in this study suggest that coronary vasomotion may be associated with LV geometry in patients with hypertension. The endothelium-dependent vasodilation is impaired progressively as LV hypertrophy advances. The endothelium-independent vasodilation of microvessels is impaired only in concentric hypertrophy. This advanced abnormality of coronary vasomotion may contribute to the high cardiovascular morbidity and mortality in patients with concentric hypertrophy.

Diagnostic and prognostic use of stress echocardiography in stable patients

Stress echocardiography is an effective diagnostic and prognostic technique in stable patients with known or suspected coronary artery disease (CAD), myocardial infarction, or chronic left ventricular dysfunction and those undergoing noncardiac surgery. Stress echocardiography is sensitive and specific for the detection and extent of CAD. Negative tests confer a high negative predictive value for cardiac events regardless of the clinical risk. Positive studies confer a high positive predictive value for ischemic events in patients with intermediate to high clinical risk. Stress echocardiography provides incremental prognostic information relative to clinical, resting echocardiographic, and angiographic data. Meta-analysis studies have shown that the diagnostic and prognostic information provided by stress echocardiography is comparable to that from radionuclide scintigraphic stress tests. Stress echocardiography may be more specific for the detection and extent of CAD, whereas radionuclide scintigraphy may be more sensitive for one-vessel disease. Sensitivities are similar for the detection and extent of disease in patients with multivessel CAD.

Molecular mechanism of mechanical stress-induced cardiac hypertrophy

Mechanical stress is a major cause of cardiac hypertrophy. Although the mechanisms by which mechanical load induces cardiomyocyte hypertrophy have long been a subject of great interest for cardiologists, the lack of a good in vitro system has hampered the understanding of the biochemical mechanisms. For these past several years, however, an in vitro neonatal cardiocyte culture system has made it possible to examine the biochemical basis for the signal transduction of mechanical stress. Passive stretch of cardiac myocytes cultured on silicone membranes activates phosphorylation cascades of many protein kinases including protein kinase C, Raf-1 kinase and extracellular signal regulated kinases, and induces the expression of specific genes as well as an increase in protein synthesis. During that process, the secretion and production of vasoactive peptides such as angiotensin II and endothelin, are increased and they play critical roles in the induction of these hypertrophic responses. Although the involvement of vasoactive peptides in the development of cardiac hypertrophy is clinically important, the "mechanoreceptor" which receives the mechanical stress and converts it into intracellular biochemical signals remained unknown. We have recently obtained evidence suggesting that ion channels and integrins may be the "mechanoreceptor", the activation of which leads to cardiac hypertrophy.

Diagnostic and Prognostic Use of Stress Echocardiography and Radionuclide Scintigraphy

Stress echocardiography and radionuclide scintigraphy are effective diagnostic and prognostic techniques in patients with known or suspected coronary artery disease (CAD), myocardial infarction (MI), chronic left ventricular dysfunction (LVD), and those undergoing noncardiac surgery. Both are sensitive and specific for the detection and extent of CAD. Negative tests confer a high negative predictive value for cardiac events irrespective of clinical risk. Positive studies confer a high positive predictive value for ischemic events in patients with intermediate to high clinical risk. Both provide incremental diagnostic and prognostic information relative to clinical, resting echocardiographic, and angiographic data. Meta-analysis studies have shown that the diagnostic and prognostic information provided by stress echocardiography is comparable with radionuclide scintigraphic stress tests. Stress echocardiography may be more specific for the detection and extent of CAD, whereas radionuclide scintigraphy may be more sensitive for single-vessel disease. Sensitivities are similar for the detection and extent of disease in patients with multivessel CAD.

Stress myocardial perfusion imaging versus echocardiography for the diagnosis and risk stratification of patients with known or suspected coronary artery disease

Stress perfusion imaging and stress echocardiography (ECHO) are both very useful for assessment of diagnosis and risk stratification of patients with coronary artery disease (CAD). Both techniques have been well validated during exercise and inotropic stress, but coronary vasodilation stress is better used in combination with perfusion imaging. The overall sensitivity for detection of CAD is slightly higher by single photon emission computed tomography (SPECT) than by two-dimensional (2D) ECHO during all stress modalities, whereas the specificity is slightly higher by ECHO, although the differences in general are not statistically significant. SPECT, however, appears to be superior to ECHO in the diagnosis of isolated circumflex stenosis, as well as for the correct identification of multivessel CAD. A substantially greater amount of information is available regarding risk stratification with SPECT than with 2D ECHO. Although the data suggest that both techniques are very useful for risk stratification of patients with stable CAD, after myocardial infarction, and for preoperative risk stratification, the risk for cardiac events is lower in the presence of a normal stress SPECT study than of a normal stress ECHO.

Diagnostic and prognostic value of vasodilator stress echocardiography in asymptomatic Type 2 diabetic patients with positive exercise thallium scintigraphy: a pilot study

AIM

To assess the diagnostic and prognostic value of vasodilator stress echocardiography in Type 2 diabetic patients with positive exercise perfusion scintigraphy.

METHODS

Of an initial cohort of 50 asymptomatic Type 2 diabetic patients undergoing exercise single photon emission computed tomography (SPECT) thallium scintigraphy, 24 had a positive thallium scan, with a reversible perfusion defect. All these 24 underwent high dose (up to 0.84 mg/kg in 10 min) dipyridamole echocardiography and coronary angiography independently of stress echocardiography results. All patients were then followed for 61+/-22 months.

RESULTS

Coronary angiography showed normal coronary arteries in 11 patients and significant (> 50% visually assessed diameter reduction in a major vessel) coronary artery disease in 13. Stress echocardiography showed 92% sensitivity and 100% specificity for non-invasive detection of coronary artery disease. During follow-up, five patients experienced cardiac events: heart failure in one, angina with subsequent revascularization in two, and myocardial infarction in two. Event-free survival was 100% in the 12 patients with negative and 58% in the 12 patients with positive stress echocardiography (P = 0.08 by Mantel-Cox test).

CONCLUSIONS

In asymptomatic Type 2 diabetic patients with stress-induced perfusion defects, vasodilator stress echocardiography is an excellent diagnostic and prognostic tool proven with long-term follow-up.

Dipyridamole stress echocardiography

Dipyridamole stress is the forerunner and prototype of pharmacological stress echo tests in the diagnosis of coronary artery disease. The safety of this test has been conclusively demonstrated as a result of extensive experience in large-scale multicenter projects. The diagnostic accuracy of dipyridamole stress echo is comparable to dobutamine and largely a function of the employed dose. Higher dosages (up to 0.84 mg/kg) are being required to achieve good sensitivity. The prognostic value has been shown to be independent and additive to clinical, exercise echocardiogram, and angiographic data. The test positive response should be titrated on the basis of severity, extent, and timing of induced dyssynergy with low positivity being associated to more anatomically and functionally severe forms of disease. Multicenter, randomized, prospective, international studies on cost-effectiveness directly comparing a noninvasive strategy centered on stress echo versus an invasive strategy centered on coronary angiography are currently ongoing.

Hyper-responsiveness to angiotensin II is related to cardiac structural adaptation in hypertensive subjects

BACKGROUND

Angiotensin II has been found to be a growth stimulating factor for myocardial cells. In humans, angiotensin II infusion causes vasoconstriction in systemic and renal vasculature and leads to aldosterone secretion. Our hypothesis was that hyper-responsiveness to angiotensin II is related to left ventricular mass in human essential hypertension.

METHODS AND RESULTS

In 30 normotensive individuals and 30 subjects with mild essential hypertension (white men, mean age 26+/-3 years), the responsiveness to angiotensin II was assessed by measuring changes in mean arterial pressure, renal blood flow, glomerular filtration rate and aldosterone secretion in response to i.v. angiotensin II infusion (0.5 and 3.0 ng/kg per min). The provoked changes to angiotensin II infusion were similar in the normotensive and hypertensive group with the exception of an exaggerated increase in mean arterial pressure in hypertensives (14+/-5 versus 10+/-5 mm Hg, P<0.001 at 3.0 ng/kg per min angiotensin II). The increase in mean arterial pressure was correlated with left ventricular mass in hypertensive subjects (angiotensin II 0.5 ng/kg per min: r = 0.49, P<0.005; angiotensin II 3.0 ng/kg per min: r = 0.35, P<0.05); no such correlation was found in the normotensive group. After taking into account baseline mean arterial pressure and body mass index, the increase in mean arterial pressure to angiotensin II 0.5 ng/kg per min was still correlated with left ventricular mass (partial r = 0.50, P<0.01). Similarly, the change of glomerular filtration rate but not of renal blood flow in response to angiotensin II 0.5 ng/kg per min was correlated with left ventricular mass, (r = 0.42, P<0.02) in the hypertensive group but not in the normotensive one. This relationship remained significant even after taking baseline glomerular filtration rate, mean arterial pressure and body mass index into account (partial r = 0.43, P<0.05).

CONCLUSION

Hyper-responsiveness to angiotensin II is related to an increased left ventricular mass in hypertensive subjects independent of blood pressure.

Significance of myocardial ischemic electrocardiographic changes during dipyridamole stress echocardiography

The aim of this study was to assess the diagnostic and prognostic value of the presence and characteristics of ischemic electrocardiographic (ECG) changes during dipyridamole stress echocardiography. The ECG response in 178 patients with echocardiographic evidence of myocardial ischemia during dipyridamole stress testing was analyzed. ECG changes occurred in 105 patients (59%). Patients with ECG changes had a higher incidence of echocardiographic signs of ischemia at a low dose than patients with an unchanged electrocardiogram (50% vs 23%; p = 0.0002). Three-vessel and/or left main coronary artery disease (CAD) was found in 41% of patients with and in 21% of patients without ECG changes (p = 0.029). During follow-up (33 +/- 19 months), 30 cardiac events occurred: 10 deaths, 6 infarctions, and 14 unstable anginas. Coronary revascularization was performed in 48 patients with and in 17 patients without ECG changes (p = 0.0022). The univariate predictors of cardiac events were: presence of ischemia in > or =4 ECG leads (p = 0.0004), echocardiographic evidence of ischemia at a low dose (p = 0.0062), ST-segment shift on precordial leads (p = 0.0094), family history of CAD (p = 0.0115), coexistence of > or =3 cardiovascular risk factors (p = 0.0156), ST-segment depression (p = 0.0172), and ECG changes during testing (p = 0.0335). At Cox analysis, occurrence of ischemia at a low dose (odds ratio 3.0; 95% confidence interval 1.3 to 6.8) and the presence of ischemia in > or =4 ECG leads (odds ratio 3.5; 95% confidence interval 1.3 to 9.3) had an independent prognostic importance. In conclusion, the presence and characteristics of ischemic ECG changes are associated with more extensive CAD and worse prognostic outlook than are echocardiographic changes alone during dipyridamole stress echocardiography.

Stress Echocardiography: A Review of the Principles and Practice

Stress echocardiography, both pharmacologic and physiological, is an established noninvasive diagnostic method of detecting coronary artery disease. It also has a role in the assessment of patients with chest pain, the assessment of cardiovascular risk before noncardiac surgery, the assessment of patients after a myocardial infarction, the detection of viability in dysfunctional myocardium, and the prediction of functional recovery. The prognostic value of stress echocardiography is emerging. In this article, we discuss the methodology, diagnostic accuracy, and various clinical applications of stress echocardiography. We also review its limitations and compared it with other noninvasive methods of assessing patients with coronary artery disease.

Value of pharmacologic stress echocardiography in risk stratification of patients with single-vessel disease: a report from the Echo-Persantine and Echo-Dobutamine International Cooperative Studies

OBJECTIVES

This study sought to verify the effectiveness of pharmacologic stress echocardiography in risk stratification of patients with single-vessel disease.

BACKGROUND

Noninvasive prognostic assessment of single-vessel disease is an unresolved issue to date.

METHODS

The study evaluated prospectively collected data from 754 patients with angiographic single-vessel disease who underwent either dipyridamole (n = 576) or dobutamine (n = 178) stress echocardiography. Invasive treatment (coronary revascularization within 3 months of stress testing) was performed in 260 patients and medical treatment in 494.

RESULTS

Echocardiographic positivity was observed in 421 patients (56%). Patients treated invasively had a higher incidence of stress test positivity (69% vs. 49%, p < 0.001) and left anterior descending coronary artery involvement (60% vs. 46%, p < 0.001) than patients maintained with medical therapy. During a mean follow-up of 37 months, 54 hard cardiac events occurred (14 deaths, 40 nonfatal infarctions): 37 in medically and 17 in invasively treated patients (7.5% vs. 6.5%, p = NS). On Cox analysis, a positive result on stress testing was the only independent prognostic predictor in medically treated patients (relative risk 2.92, 95% confidence interval 1.29 to 6.59). The 4-year infarction-free survival rate was higher for a negative than a positive stress test result in medically (93.9% vs. 87.3%, p = 0.009) but not invasively treated patients (92.7% vs. 97.1%, p = 0.545). Moreover, a significantly higher 4-year infarction-free survival rate was found in invasively versus medically treated patients with a positive (p = 0.012), but not in those with a negative, stress test result (p = 0.853).

CONCLUSIONS

Pharmacologic stress echocardiography is effective in risk stratification of single-vessel disease and can accurately discriminate patients in whom coronary revascularization can have the maximal beneficial effect. These findings have a potential favorable impact on the cost-effectiveness of invasive procedures.

Diagnostic and prognostic implications of left ventricular cavity obliteration response to dobutamine echocardiography

Left ventricular (LV) cavity obliteration during dobutamine echocardiography (DE) indicates a vigorous inotropic response to stress. Such a response may suggest the absence of coronary artery disease (CAD), but a small LV cavity may also preclude recognition of wall motion abnormalities. We sought to determine the frequency, correlates, accuracy, and prognostic value of the LV cavity obliteration response in 336 consecutive patients who underwent coronary angiography within 1 year of DE. Cavity obliteration was defined by contact of the opposite walls in the apical views during DE, and ischemia by detection of a new or worsening wall motion abnormality. Sensitivity was based on comparison with coronary anatomy in 220 patients without prior revascularization. The prognostic implications of cavity obliteration were examined by follow-up of 324 patients (96%) over 23 +/- 9 months for death, myocardial infarction, and late revascularization. Cavity obliteration was present in 86 of the 336 DE studies (26%). Baseline and stress hemodynamics were not predictive of cavity obliteration, which was associated with LV hypertrophy and female gender (p <0.0001), and inversely related to LV systolic dysfunction and use of angiotensin-converting enzyme inhibitors or diuretics (p <0.02). The sensitivity of DE was less in patients with cavity obliteration than the remainder, especially in single vessel (46% vs 92%, p <0.001) but also in multivessel CAD (73% vs 95%, p = 0.01). Irrespective of DE and angiographic results, cavity obliteration was a negative predictor for cardiac events (RR 0.42, 95% confidence interval [CI] 0.21 to 0.87, p = 0.02) and death (RR 0.14, 95% CI 0.02 to 1.09, p = 0.06). Even after exclusion of patients with LV dysfunction, cavity obliteration was an independent predictor of freedom from events (RR 0.41, 95% CI 0.19 to 0.88, p = 0.02). Thus, LV cavity obliteration is a frequent response to DE, which compromises the sensitivity of DE but is correlated paradoxically with a favorable clinical outcome.

ECG in stress testing: child of a lesser diagnostic god?

When new technologies are added to the previously existing ones, the latter can be prematurely discarded and judged obsolete not only on the basis of rational scientific facts, but also on irrational trends. Old techniques, like electrocardiography, suffer from diagnostic ambiguities that can be solved by combination with a cardiac imaging technique, like stress echocardiography. ECG monitoring during all forms of stress testing can still offer surprising dividends for a better understanding of the complex physiology of coronary artery disease, a better clinical characterization of patients with microvascular angina, and may serve as an important adjunct marker to cardiac imaging techniques.

Use of exercise echocardiography for prognostic evaluation of patients with known or suspected coronary artery disease

OBJECTIVES

This study prospectively compared the incremental prognostic benefit of exercise echocardiography with that of exercise testing in a large cohort.

BACKGROUND

Exercise echocardiography is widely accepted as a diagnostic tool, but the prognostic information provided by this test, incremental to clinical and stress testing evaluation, is ill-defined.

METHODS

Clinical, exercise and echocardiographic variables were studied in a consecutive group of 500 patients undergoing exercise echocardiography. After exclusion of patients who underwent revascularization within 3 months of the stress test (n = 16, 3%) and those lost to follow-up (n = 21, 4%), the remaining 463 patients (mean [+/-SD] age 57 +/- 12 years, 302 men) were followed-up for 44 +/- 11 months. Outcome was related to the exercise and echocardiographic findings, and the incremental prognostic benefit of exercise echocardiography was compared with that of standard exercise testing.

RESULTS

Cardiac events occurred in 81 patients (17%), including 33 (7%) with spontaneous events (cardiac death, myocardial infarction and unstable angina) and 48 with late revascularizations due to progressive symptoms. In a multivariate Cox proportional hazards model, the likelihood of any cardiac event was increased in the presence of ischemia (relative risk [RR] 5.06, 95% confidence interval [CI] 3.09 to 8.29, p < 0.001) and lessened by more maximal stress, measured as percent age-predicted maximal heart rate (RR per 5% increment 0.84, 95% CI 0.77 to 0.92, p < 0.001). Spontaneous events were more strongly predicted by ischemia (RR 8.20, 95% CI 3.41 to 19.71, p < 0.001) and percent age-predicted maximal heart rate (RR per 5% increment 0.78, 95% CI 0.67 to 0.91, p < 0.001). An interactive logistic regression model showed that the addition of echocardiographic to exercise and clinical data offered incremental predictive value.

CONCLUSIONS

The presence of ischemia on the exercise echocardiogram can predict whether patients will experience an event. This relation is independent of, and incremental to, clinical and exercise data.

Detection of patients with restenosis after PTCA by dipyridamole-atropine-stress-echocardiography

Stress-echocardiography (SE) has been proven to be a valuable method for the diagnosis of coronary artery disease. For patients who cannot exercise, pharmacological stress-echocardiography represents an alternative method for the induction of cardiovascular stress. Few studies exist concerning the value of dipyridamole-SE for the detection of restenosis in patients after primary successful PTCA. It has been demonstrated that the addition of atropine can significantly increase the diagnostic potential of dipyridamole-SE, especially in patients with 1- or 2-vessel disease. The purpose of our study was to investigate the diagnostic value of high-dose dipyridamole-SE plus atropine (DASE) for the detection of restenosis after primary successful PTCA. We investigated 65 patients 3-6 months after PTCA before a control angiography was performed. Restenosis was defined as > 70% lumen narrowing, determined by quantitative coronary angiography. In 20/27 patients with restenosis, the DASE was pathological (sensitivity 74%); in 34/38 patients without restenosis the DASE was normal or showed no induced WMA (specificity 89%). Patients with tight restenosis (> 90%) were always correctly detected by DASE. Concerning the different vessels, restenosis of the LAD was correctly predicted by DASE in 11/12 patients, restenosis of the LCX in 6/9 patients and restenosis of the RCA in 8/11 patients. From the results of our study we conclude that DASE is a reliable diagnostic method for the non-invasive evaluation of patients after PTCA. DASE can identify patients with relevant restenosis after PTCA and help to select those patients who will probably benefit from further coronary interventions, for repeat angiography.

Prognostic value of dobutamine echocardiography early after uncomplicated acute myocardial infarction: a comparison with exercise electrocardiography

OBJECTIVES

This study sought to assess the relative prognostic power of dobutamine echocardiography and exercise electrocardiography after acute myocardial infarction.

BACKGROUND

The prognostic value of dobutamine echocardiography early after acute myocardial infarction has not yet been reported.

METHODS

One hundred seventy-eight patients (mean age 58 +/- 9 years) with a first uncomplicated acute myocardial infarction underwent predischarge dobutamine echocardiography (5 to 40 micrograms/kg body weight per min, plus atropine if needed) and symptom-limited bicycle exercise electrocardiography and were followed up for 17 +/- 13 months. Stress-induced dyssynergy and ST segment depression > 1 mm were considered criteria of positivity for dobutamine echocardiography and exercise electrocardiography, respectively.

RESULTS

Dobutamine echocardiography was positive in 83 patients and exercise electrocardiography in 60. At follow-up there were 5 deaths, 6 nonfatal myocardial infarctions (11 hard events) and 20 cases of unstable angina. Dobutamine echocardiography and exercise electrocardiography had similar negative predictive values both for all events (88% and 86%, respectively) and for hard events (98% and 95%, respectively). The hard events rate was significantly higher in patients with positive rather than negative dobutamine echocardiography (relative risk [RR] 5.15, 95% confidence interval [CI] 1.14 to 23.16), although there was no difference between patients with positive and negative exercise electrocardiograms. When Cox analysis was performed, dobutamine echocardiography had an independent prognostic value both for all events (RR 2.88, 95% CI 1.37 to 6.08) and for hard events (RR 6.56, 95% CI 1.42 to 30.46).

CONCLUSIONS

After uncomplicated acute myocardial infarction, dobutamine echocardiography and exercise electrocardiography have a similar high negative predictive value for both all events and hard events only. Positive dobutamine echocardiography, but not positive exercise electrocardiography, identifies a group of patients at higher risk of subsequent cardiac events.

Continuous measurement of hemodynamic alterations during pharmacologic cardiovascular stress using automated impedance cardiography

The contribution of computerized impedance cardiography in monitoring and differentiating cardiovascular responses to pharmacologic stress after the administration of dipyridamole (group 1, n = 24) or dobutamine (group 2, n = 26) was investigated during stress echocardiography. Heart rate, stroke volume index, cardiac index and systemic vascular resistance index were evaluated continuously with an automated, computerized, signal-averaged impedance cardiography system. Dipyridamole had little average effect on heart rate, stroke volume index, and cardiac index. The responses were similar in patients with positive (n = 9) or negative (n = 15) stress echocardiography test results (as characterized by echocardiographic wall-motion abnormalities). Dobutamine induced a similar mean increase in heart rate in patients with negative (n = 13) or positive (n = 13) results on stress echocardiography. The mean increase in stroke volume index induced by dobutamine was greater in patients with negative stress echocardiography test results than in patients with stress-induced wall-motion abnormalities. This distinction was also seen in the cardiac index; the mean change in patients with negative stress echocardiography test results was larger than in patients with positive results. It is concluded that automated computerized impedance cardiography not only allows surveying and monitoring hemodynamic changes during pharmacologic stress echocardiography but also contributes to differentiation of pathologic stress responses.

Usefulness of dipyridamole transesophageal echocardiography in the evaluation of myocardial ischemia and coronary artery flow

High-dose dipyridamole transesophageal stress echocardiography has recently been proposed as a useful and safe method to assess myocardial ischemia in patients with poor transthoracic acoustic window. It has also been shown that transesophageal echocardiography (TEE) allows the study of coronary blood flow reserve (CBFR) in the left anterior descending artery (LAD). The aim of our study was to assess whether the morphologic information and pathophysiologic data on CBFR and myocardial ischemia can be collected by a single stress TEE without comprimizing its feasibility, safety and accuracy. We studied, 29 patient with known or suspected CAD (previous myocardial infarction or angina) (Group A), and as a control group, we studied 11 patients with mitral disease or mitral prostheses (Group B). All patients underwent the coronary angiography. None of Group B patients showed significant coronary artery stenosis (> 70%). In baseline conditions left ventricular wall motion and LAD coronary blood flow velocity (CBFV) were also evaluated. The following CBFV parameters were measured: maximal diastolic velocity (MaxDV), mean diastolic velocity (MnDV), maximal systolic velocity (MaxSV), mean systolic velocity (MnSV). The ratios of dipyridamole to rest maximal and o mean to diastolic velocities (MaxDV-Dip/Max DV-rest; MnDv-Dip/MnDV-rest) were measured as indexes of CBFR. No side effects were observed and the test could be completed in all patients (feasibility 100%). Wall motion analysis was adequate in all patients (feasibility 100%). Comparison between wall motion analysis was obtained and angiographic findings shown that the overall sensitivity and specificity of TEE were 84% and 93% respectively. Sensitivity for one, two and three vessel disease was 60%, 70% and 100%, respectively. LAD CBFV was adequately recorded in 85% of patients. CBFR parameters showed a significant difference between the two groups (Max DV-Dip/Max DV-rest: 1.67 +/- 0.7 vs. 2.73 +/- 0.6, P < 0.001); comparison between Group B patients and those of Group A with angiographically documented LAD stenosis showed a statistically significant difference in CBFR parameters (MaxDV-Dip/MnDV-rest, 2.73 +/- 0.6 vs. 1.65 +/- 0.7, P < 0.001, MnDV-Dip/MnDV-rest, 2.56 +/- 0.5 vs. 1.69 +/- 0.6 < 0.001). We conclude that transesophageal stress echocardiography is a useful method to study CAD and that it is possible to assess both morphologic and pathophysiologic information during a single examination.