Prognostic Value of Pharmacological Stress Echocardiography Is Affected by Concomitant Antiischemic Therapy at the Time of Testing

The Hypoxia-Adenosine Link during Myocardial Ischemia-Reperfusion Injury

Despite increasing availability and more successful interventional approaches to restore coronary reperfusion, myocardial ischemia-reperfusion injury is a substantial cause of morbidity and mortality worldwide. During myocardial ischemia, the myocardium becomes profoundly hypoxic, thus causing stabilization of hypoxia-inducible transcription factors (HIF). Stabilization of HIF leads to a transcriptional program that promotes adaptation to hypoxia and cellular survival. Transcriptional consequences of HIF stabilization include increases in extracellular production and signaling effects of adenosine. Extracellular adenosine functions as a signaling molecule via the activation of adenosine receptors. Several studies implicated adenosine signaling in cardioprotection, particularly through the activation of the Adora2a and Adora2b receptors. Adenosine receptor activation can lead to metabolic adaptation to enhance ischemia tolerance or dampen myocardial reperfusion injury via signaling events on immune cells. Many studies highlight that clinical strategies to target the hypoxia-adenosine link could be considered for clinical trials. This could be achieved by using pharmacologic HIF activators or by directly enhancing extracellular adenosine production or signaling as a therapy for patients with acute myocardial infarction, or undergoing cardiac surgery.

Changing Paradigms in the Diagnosis of Ischemic Heart Disease by Multimodality Imaging

Coronary artery disease (CAD) represents the most common cardiovascular disease, with high morbidity and mortality. Historically patients with chest pain of suspected coronary origin have been assessed with functional tests, capable to detect haemodynamic consequences of coronary obstructions through depiction of electrocardiographic changes, myocardial perfusion defects or regional wall motion abnormalities under stress condition. Stress echocardiography (SE), single-photon emission computed tomography (SPECT), positron emission tomography (PET) and cardiovascular magnetic resonance (CMR) represent the functional techniques currently available, and technical developments contributed to increased diagnostic performance of these techniques. More recently, cardiac computed tomography angiography (cCTA) has been developed as a non-invasive anatomical test for a direct visualisation of coronary vessels and detailed description of atherosclerotic burden. Cardiovascular imaging techniques have dramatically enhanced our knowledge regarding physiological aspects and myocardial implications of CAD. Recently, after the publication of important trials, international guidelines recognised these changes, updating indications and level of recommendations. This review aims to summarise current standards with main novelties and specific limitations, and a diagnostic algorithm for up-to-date clinical management is also proposed.

Preoperative cardiac assessment in liver transplant candidates

New and extended indications, older age, higher cardiovascular risk, and the long-standing cirrhosis-associated complications mandate specific skills for an appropriate preoperative assessment of the liver transplant (LT) candidate. The incidence of cardiac diseases (dysrhythmias, cardiomyopathies, coronary artery disease, valvular heart disease) are increasing among LT recipients: however, no consensus exists among clinical practice guidelines for cardiovascular screening and risk stratification. In spite of different "transplant center-centered protocols", basic "pillars" are common (electrocardiography, baseline echocardiography, functional assessment). Owing to intrinsic limitations, yields and relevance of noninvasive stress tests, under constant scrutiny even if used, are discussed, focusing the definition of the "high risk" candidate and exploring noninvasive imaging and new forms of stress imaging. The aim is to find an appropriate and rational stepwise algorithm. The final commitment is to select the right candidate for a finite resource, the graft, able to save (and change) lives.

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.

Drop-off in positivity rate of stress echocardiography based on regional wall motion abnormalities over the last three decades

Previous studies have suggested a decline in positivity of stress cardiac imaging based on regional wall motion abnormalities (RWMA). To assess the rate of RWMA positivity of stress echocardiography (SE) over 3 decades in the same primary care SE lab. We retrospectively assessed the rate of SE positivity in 7626 SE tests (dipyridamole in 5053, dobutamine in 2496, exercise in 77) in consecutive patients with known or suspected coronary artery disease and /or heart failure who performed SE in a primary care referral center from April 1991 to May 2018. Starting April 2005, SE based on RWMA was complemented by assessment of coronary flow velocity reserve (CFVR) of the left anterior descending coronary artery. Starting October 2016, we added left ventricular contractile reserve (LVCR). Starting October 2016, we also added B-lines by lung ultrasound. There was a progressive decline over time in the rate of SE positivity based on RWMA from 24% (1991-1999) to 10% (2000-2009) down to 4% (2010-2018) (p < 0.0001). Positivity rate was 29% with CFVR, 16% with LVCR, and 12% with B-lines. Over three decades, we observed a dramatic decline in SE positivity rate based on classical RWMA. In the last decade, the positivity rate rose sharply thanks to the stepwise introduction of CFVR, LVCR and B-lines as additional positivity criteria in integrated quadruple SE.

The new clinical standard of integrated quadruple stress echocardiography with ABCD protocol

BACKGROUND

The detection of regional wall motion abnormalities is the cornerstone of stress echocardiography. Today, stress echo shows increasing trends of utilization due to growing concerns for radiation risk, higher cost and stronger environmental impact of competing techniques. However, it has also limitations: underused ability to identify factors of clinical vulnerability outside coronary artery stenosis; operator-dependence; low positivity rate in contemporary populations; intermediate risk associated with a negative test; limited value of wall motion beyond coronary artery disease. Nevertheless, stress echo has potential to adapt to a changing environment and overcome its current limitations.

INTEGRATED-QUADRUPLE STRESS-ECHO

Four parameters now converge conceptually, logistically, and methodologically in the Integrated Quadruple (IQ)-stress echo. They are: 1- regional wall motion abnormalities; 2-B-lines measured by lung ultrasound; 3-left ventricular contractile reserve assessed as the stress/rest ratio of force (systolic arterial pressure by cuff sphygmomanometer/end-systolic volume from 2D); 4- coronary flow velocity reserve on left anterior descending coronary artery (with color-Doppler guided pulsed wave Doppler). IQ-Stress echo allows a synoptic functional assessment of epicardial coronary artery stenosis (wall motion), lung water (B-lines), myocardial function (left ventricular contractile reserve) and coronary small vessels (coronary flow velocity reserve in mid or distal left anterior descending artery). In "ABCD" protocol, A stands for Asynergy (ischemic vs non-ischemic heart); B for B-lines (wet vs dry lung); C for Contractile reserve (weak vs strong heart); D for Doppler flowmetry (warm vs cold heart, since the hyperemic blood flow increases the local temperature of the myocardium). From the technical (acquisition/analysis) viewpoint and required training, B-lines are the kindergarten, left ventricular contractile reserve the primary (for acquisition) and secondary (for analysis) school, wall motion the university, and coronary flow velocity reserve the PhD program of stress echo.

CONCLUSION

Stress echo is changing. As an old landline telephone with only one function, yesterday stress echo used one sign (regional wall motion abnormalities) for one patient with coronary artery disease. As a versatile smart-phone with multiple applications, stress echo today uses many signs for different pathophysiological and clinical targets. Large scale effectiveness studies are now in progress in the Stress Echo2020 project with the omnivorous "ABCD" protocol.

Integrated quadruple stress echocardiography

Stress echocardiography (SE) is an established diagnostic technique. For 40 years, the cornerstone of the technique has been the detection of regional wall motion abnormalities (RWMA), due to the underlying physiologically-relevant epicardial coronary artery stenosis. In the last decade, three new parameters (more objective than RWMA) have shown the potential to integrate and complement RWMA: 1) B-lines, also known as ultrasound lung comets, as a marker of extravascular lung water, measured using lung ultrasound with the 4-site simplified scan symmetrically of the antero-lateral thorax on the third intercostal space, from mid-axillary to anterior axillary and mid-clavicular line; 2) left ventricular contractile reserve (LVCR), assessed as the peak stress/rest ratio of left ventricular force, also known as elastance (systolic arterial pressure by cuff sphygmomanometer/end-systolic volume from 2D echocardiography); 3) coronary flow velocity reserve (CFVR) on left anterior descending coronary artery, calculated as peak stress/rest ratio of diastolic peak flow velocity assessed using pulsed-wave Doppler. The 4 parameters (RWMA, B-lines, LVCR and CFVR) now converge conceptually, logistically, and methodologically in the Integrated Quadruple (IQ)-SE. IQ-SE optimizes the versatility of SE to include in a one-stop shop the core "ABCD" (asynergy+B-lines+contractile reserve+Doppler flowmetry) protocol. It allows a synoptic assessment of parameters mirroring the epicardial artery stenosis (RWMA), interstitial lung water (B-lines), myocardial function (LVCR) and small coronary vessels (CFVR). Each variable has a clear clinical correlate, different and complementary to all others: RWMA identify an ischemic vs. non-ischemic heart; B-lines a wet vs. dry lung; LVCR a strong vs. weak heart; CFVR a warm vs. cold heart. IQ-SE is highly feasible, with minimal increase in the imaging and analysis time, and obvious diagnostic and prognostic impact also beyond coronary artery disease - especially in heart failure. Large scale effectiveness studies with IQ-SE are now under way with the Stress Echo 2020 Study, and will provide the necessary evidence base prior to large scale acceptance of the technique.

Baseline mitral regurgitation predicts outcome in patients referred for dobutamine stress echocardiography

A number of parameters recorded during dobutamine stress echocardiography (DSE) are associated with worse outcome. However, the relative importance of baseline mitral regurgitation (MR) is unknown. The aim of this study was to assess the prevalence and associated implications of functional MR with long-term mortality in a large cohort of patients referred for DSE. 6745 patients (mean age 64.9 ± 12.2 years) were studied. Demographic, baseline and peak DSE data were collected. All-cause mortality was retrospectively analyzed. DSE was successfully completed in all patients with no adverse outcomes. MR was present in 1019 (15.1%) patients. During a mean follow up of 5.1 ± 1.8 years, 1642 (24.3%) patients died and MR was significantly associated with increased all-cause mortality (p < 0.001). With Kaplan-Meier analysis, survival was significantly worse for patients with moderate and severe MR (p < 0.001). With multivariate Cox regression analysis, moderate and severe MR (HR 2.78; 95% CI 2.17-3.57 and HR 3.62; 95% CI 2.89-4.53, respectively) were independently associated with all-cause mortality. The addition of MR to C statistic models significantly improved discrimination. MR is associated with all-cause mortality and adds incremental prognostic information among patients referred for DSE. The presence of MR should be taken into account when evaluating the prognostic significance of DSE results.

Simple six-item clinical score improves risk prediction capability of stress echocardiography

Objectives

To assess the value of a simple score integrating non-ischaemia-related variables in expanding the wall motion abnormalities risk power during stress echocardiography (SE).

Methods

Study includes 14 279 patients who underwent SE for evaluation of coronary artery disease. All-cause death was the end point. Patients were randomly divided into the modelling and validation group of equal size. In the modelling group, multivariate analysis was conducted using clinical, rest and SE data, and a score was obtained from the number of non-ischaemia-related independent prognostic predictors. The score prognostic capability was compared in both groups.

Results

During a median follow-up of 31 months, 1230 patients died: 622 (9%) in the modelling and 608 (9%) in the validation group (p=0.68). Independent predictors of mortality were ischaemia at SE (HR 1.77, 95% CI 1.49 to 2.12; p<0.0001) and six other parameters: age>65 years, wall motion at rest, diabetes, left bundle branch block, anti-ischaemic therapy and male sex. Risk score resulted prognostically effective in the modelling and validation groups, both with and without inducible ischaemia subset. When risk score was included in the multivariate analysis, besides ischaemia at SE it was the only independent predictor of mortality in the modelling (HR 1.70, 95% CI 1.60 to 1.82; p<0.0001), in the validation (HR 1.77, 95% CI 1.65 to 1.90; p<0.0001) and in the overall group (HR 1.73, 95% CI 1.66 to 1.82; p<0.0001).

Conclusions

Simple clinical variables may be able to optimise SE risk stratification.

Feasibility, symptoms, adverse effects, and complications associated with noninvasive assessment of coronary flow velocity reserve in women with suspected or known coronary artery disease

BACKGROUND

Microvascular coronary impairment, defined as reduced coronary flow reserve, represents the predominant etiologic mechanism of ischemia in women with chest pain and no obstructive coronary artery disease. Transthoracic echocardiography (TTE) is a noninvasive method for assessing coronary flow velocity reserve (CFVR) in the left anterior descending coronary artery (LAD). The purpose of this investigation was to define the safety profile, feasibility, adverse events, and rate of complications of the test in women with suspected CAD.

METHODS

We evaluated CFVR in LAD with TTE during adenosine infusion in 1455 women aged 66.4±11.9 years.

RESULTS

A complete CFVR study was achieved in 1429 pts (feasibility 98.2%), the test being performed also in the early phase of acute coronary syndrome and on obese patients. Minor symptoms or adverse effects occurred in 43.7% of patients not requiring test termination: hyperpnea (16.7%), flushing (9.4%), atypical chest pain (9.9%), headache (6.6%), minor arrhythmias (2.9%), chest pain with EKG changes (1.5%) were the symptoms reported. No major complications were observed.

CONCLUSIONS

Noninvasive assessment of CFVR in LAD by TTE is a very feasible method with very low incidence of adverse events and complications in women with suspected or known CAD. It is safe and can be used when evaluating female patients with atherosclerotic LAD disease or with coronary microvascular impairment.

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.

Stress echo 2020: the international stress echo study in ischemic and non-ischemic heart disease

BACKGROUND

Stress echocardiography (SE) has an established role in evidence-based guidelines, but recently its breadth and variety of applications have extended well beyond coronary artery disease (CAD). We lack a prospective research study of SE applications, in and beyond CAD, also considering a variety of signs in addition to regional wall motion abnormalities.

METHODS

In a prospective, multicenter, international, observational study design, > 100 certified high-volume SE labs (initially from Italy, Brazil, Hungary, and Serbia) will be networked with an organized system of clinical, laboratory and imaging data collection at the time of physical or pharmacological SE, with structured follow-up information. The study is endorsed by the Italian Society of Cardiovascular Echography and organized in 10 subprojects focusing on: contractile reserve for prediction of cardiac resynchronization or medical therapy response; stress B-lines in heart failure; hypertrophic cardiomyopathy; heart failure with preserved ejection fraction; mitral regurgitation after either transcatheter or surgical aortic valve replacement; outdoor SE in extreme physiology; right ventricular contractile reserve in repaired Tetralogy of Fallot; suspected or initial pulmonary arterial hypertension; coronary flow velocity, left ventricular elastance reserve and B-lines in known or suspected CAD; identification of subclinical familial disease in genotype-positive, phenotype- negative healthy relatives of inherited disease (such as hypertrophic cardiomyopathy).

RESULTS

We expect to recruit about 10,000 patients over a 5-year period (2016-2020), with sample sizes ranging from 5,000 for coronary flow velocity/ left ventricular elastance/ B-lines in CAD to around 250 for hypertrophic cardiomyopathy or repaired Tetralogy of Fallot. This data-base will allow to investigate technical questions such as feasibility and reproducibility of various SE parameters and to assess their prognostic value in different clinical scenarios.

CONCLUSIONS

The study will create the cultural, informatic and scientific infrastructure connecting high-volume, accredited SE labs, sharing common criteria of indication, execution, reporting and image storage of SE to obtain original safety, feasibility, and outcome data in evidence-poor diagnostic fields, also outside the established core application of SE in CAD based on regional wall motion abnormalities. The study will standardize procedures, validate emerging signs, and integrate the new information with established knowledge, helping to build a next-generation SE lab without inner walls.

Prognostic value of cardiac power output to left ventricular mass in patients with left ventricular dysfunction and dobutamine stress echo negative by wall motion criteria

AIMS

Cardiac power output to left ventricular mass (power/mass) is an index of myocardial efficiency reflecting the rate at which cardiac work is delivered with respect to the potential energy stored in the left ventricular mass. In the present study, we sought to investigate the capability of power/mass assessed at peak of dobutamine stress echocardiography to predict mortality in patients with ischaemic cardiomyopathy and no inducible ischaemia.

METHODS AND RESULTS

One-hundred eleven patients (95 males; age 68 ± 10 years) with 35 ± 7% mean left ventricular ejection fraction and a dobutamine stress echocardiography (up to 40 µg/kg/min) negative by wall motion criteria formed the study population. Power/mass at peak stress was obtained as the product of a constant (K = 2.22 × 10^-1) with cardiac output and the mean arterial pressure divided by left ventricular mass to convert the units to W/100 g. Patients were followed up for a median of 29 months (inter-quartile range 16-72 months). All-cause mortality was the only accepted clinical end point. Mean peak-stress power/mass was 0.70 ± 0.31 W/100 g. During follow-up, 29 deaths (26%) were registered. With a receiver operating characteristic analysis, a peak-stress power/mass ≤0.50 W/100 g [area under curve 0.72 (95% CI 0.63; 0.80), sensitivity 59%, specificity 80%] was the best value for predicting mortality. Univariate prognostic indicators were age, male sex, peak-stress ejection fraction, peak-stress stroke volume, peak-stress cardiac output, peak-stress cardiac power output ≤1.48 W, and peak-stress power/mass ≤0.50 W/100 g. At multivariate analysis, age (HR 1.08, 95% CI 1.04; 1.14; P = 0.004) and peak-stress power/mass ≤0.50 W/100 g (HR 4.05, 95% CI 1.36; 12.00; P = 0.01) provided independent prognostic information. Three-year mortality was 14% in patients with peak-stress power/mass >0.50 W/100 g and 47% in those with peak-stress power/mass ≤0.50 W/100 g (log-rank 20.4; P < 0.0001).

CONCLUSION

Power/mass assessed at peak of dobutamine stress echocardiography allows effective prognostication in patients with ischaemic cardiomyopathy and test result negative by wall motion criteria. In particular, a peak-stress power/mass ≤50 W/100 g is a strong and multivariable predictor of mortality.

Prediction of mortality by stress echocardiography in 2835 diabetic and 11 305 nondiabetic patients

BACKGROUND

To compare the capability by stress echocardiography results to predict overall mortality in a large unselected cohort of diabetic and nondiabetic patients.

METHODS AND RESULTS

The study group comprised 14 140 patients (2835 diabetics and 11 305 nondiabetics) who underwent stress echocardiography for evaluation of known (n=5671) or suspected (n=8469) coronary artery disease. Ischemia at stress echocardiography was observed in 768 (27%) diabetics and 2644 (23%) nondiabetics. During a median follow-up of 30 months (first quartile, 9; third quartile, 63), 1213 patients died. In diabetics, multivariable indicators of mortality were age (hazard ratio [HR], 1.07, 95% confidence interval [CI], 1.06-1.09), rest wall motion abnormality (HR, 2.43; 95% CI, 1.83-3.22), and ischemia at stress echocardiography (HR, 1.71; 95% CI, 1.34-2.18). In nondiabetics, multivariable indicators of mortality were age (HR, 1.07; 95% CI, 1.06-1.08), rest wall motion abnormality (HR, 2.19; 95% CI, 1.86-2.57), male sex (HR, 1.65; 95% CI, 1.41-1.93), ischemia at stress echocardiography (HR, 1.54; 95% CI, 1.32-1.80), and antischemic therapy at the time of test (HR, 1.15; 95% CI, 1.00-1.32). In stress echo negative subjects for ischemia, antischemic therapy showed increased annual mortality in nondiabetic patients with (3.8% versus 3.1%; P=0.04) or without rest wall motion abnormality (1.6% versus 0.9%; P<0.0001); it failed to do so in diabetic patients with (5.7% versus 5.8%; P=0.89) or without rest wall motion abnormality (2.6% versus 1.9%; P=0.10).

CONCLUSIONS

Ischemia at stress echocardiography is a strong and independent predictor of total mortality in diabetic as well as nondiabetic patients. Antischemic therapy markedly affects the negative predictive value of stress echocardiography in nondiabetic patients, whereas it is prognostically neutral in the diabetic population.

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.

Prognostic effect of coronary flow reserve in women versus men with chest pain syndrome and normal dipyridamole stress echocardiography

The aim of this study was to investigate the prognostic effect of coronary flow reserve (CFR) on left anterior descending artery (LAD) in women and men with chest pain of unknown origin and normal stress echocardiogram. The study population consisted of 1,660 patients (906 women, 754 men) with chest pain syndrome, no wall motion abnormality on echocardiogram at rest, and dipyridamole (up to 0.84 mg/kg over 6 minutes) stress echocardiogram negative for wall motion criteria. All had undergone stress echocardiography with combined evaluation of CFR on LAD by Doppler. A CFR value ≤2.0 was considered abnormal. Median duration of follow-up was 19 months (interquartile range 10 to 34). Abnormal CFR was assessed in 171 women (19%) and 147 men (19%, p = 0.80). During follow-up, 80 events (20 deaths, 13 ST-elevation myocardial infarctions, and 47 non-ST-elevation myocardial infarctions) occurred. In addition, 128 patients underwent revascularization and were censored. CFR ≤2.0 on LAD was independently associated with prognosis in women (hazard ratio [HR] 16.48, 95% confidence interval [CI] 7.17 to 37.85, p <0.0001) and in men (HR 6.23, 95% CI 3.42 to 11.33, p <0.0001). Antianginal therapy at time of testing (HR 2.11, 95% CI 1.14 to 3.90, p = 0.02) was also a multivariable prognostic predictor in men. Four-year event rate associated with CFR values ≤2.0 and >2.0 were, respectively, 27% and 2% in women (p <0.0001) and 42% and 8% in men (p <0.0001). In conclusion, decreased CFR on LAD is associated with markedly increased risk in women and men with chest pain syndrome and a normal result of dipyridamole stress echocardiography. Conversely, preserved CFR on LAD predicts excellent survival, particularly in women.

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.

Prognostic value of dobutamine stress echocardiography with early injection of atropine with versus without chronic beta-blocker therapy in patients with known or suspected coronary heart disease

Although a new protocol of dobutamine stress echocardiography with the early injection of atropine (EA-DSE) has been demonstrated to be useful in reducing adverse effects and increasing the number of effective tests and to have similar accuracy for detecting coronary artery disease (CAD) compared with conventional protocols, no data exist regarding its ability to predict long-term events. The aim of this study was to determine the prognostic value of EA-DSE and the effects of the long-term use of beta blockers on it. A retrospective evaluation of 844 patients who underwent EA-DSE for known or suspected CAD was performed; 309 (37%) were receiving beta blockers. During a median follow-up period of 24 months, 102 events (12%) occurred. On univariate analysis, predictors of events were the ejection fraction (p <0.001), male gender (p <0.001), previous myocardial infarction (p <0.001), angiotensin-converting enzyme inhibitor therapy (p = 0.021), calcium channel blocker therapy (p = 0.034), and abnormal results on EA-DSE (p <0.001). On multivariate analysis, the independent predictors of events were male gender (relative risk [RR] 1.78, 95% confidence interval [CI] 1.13 to 2.81, p = 0.013) and abnormal results on EA-DSE (RR 4.45, 95% CI 2.84 to 7.01, p <0.0001). Normal results on EA-DSE with beta blockers were associated with a nonsignificant higher incidence of events than normal results on EA-DSE without beta blockers (RR 1.29, 95% CI 0.58 to 2.87, p = 0.54). Abnormal results on EA-DSE with beta blockers had an RR of 4.97 (95% CI 2.79 to 8.87, p <0.001) compared with normal results, while abnormal results on EA-DSE without beta blockers had an RR of 5.96 (95% CI 3.41 to 10.44, p <0.001) for events, with no difference between groups (p = 0.36). In conclusion, the detection of fixed or inducible wall motion abnormalities during EA-DSE was an independent predictor of long-term events in patients with known or suspected CAD. The prognostic value of EA-DSE was not affected by the long-term use of beta blockers.

The prognostic value of Doppler echocardiographic-derived coronary flow reserve is not affected by concomitant antiischemic therapy at the time of testing

BACKGROUND

When wall motion abnormality is the diagnostic end point, concomitant antiischemic therapy heavily modulates the prognostic value of dipyridamole echocardiography test (DET). A negative test result is less benign, and a positive test result is more malignant if performed under therapy. Recently, coronary flow reserve (CFR) was added to wall motion in dual imaging DET. The aim of the study was to determine whether antianginal medications affect the prognostic value of Doppler echocardiographic-derived CFR in patients with known or suspected coronary artery disease undergoing DET.

METHODS

In a prospective, multicenter, observational study, we evaluated 1,779 patients (1,072 males; 64 +/- 11 years) who underwent high-dose dipyridamole (0.84 mg/kg for 6 minutes) stress echo with CFR evaluation of left anterior descending (LAD) artery by Doppler.

RESULTS

Seven hundred thirty-three (41%) patients were on antiischemic therapy at time of testing (nitrates and/or calcium antagonists and/or beta-blockers). Mean CFR was 2.3. +/- 0.6. At individual patient analysis, 1,141 patients had normal (CFR >2.0) and 638 had abnormal (CFR <or=2.0) CFR on LAD. During a median follow-up of 36 months, 263 events occurred as follows: 36 deaths and 59 ST-elevation myocardial infarctions (STEMIs) and 168 non-STEMIs (NSTEMIs). Survival was highest in patients with normal CFR and lowest in patients with abnormal CFR (87% vs 34%, P = .0001). Survival was comparable in patients with normal CFR on and off therapy and in patients with abnormal CFR on and off therapy. At multivariable analysis, hypertension (hazard ratio [HR] 1.5, 95% CI 1.0-1.9, P = .010), DET positivity for regional wall motion abnormalities (HR 5.7, 95% CI 4.3-7.4, P = .000), an abnormal CFR on LAD (HR 3.3, 95% CI 2.5-4.4, P = .000) were independent prognostic predictors of hard cardiac events.

CONCLUSION

Ongoing antiischemic therapy at the time of testing does not modulate the prognostic value of Doppler echocardiographic-derived coronary flow reserve.

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.

Ischemia induced by transesophageal atrial pacing stress echocardiography predicts long-term mortality

OBJECTIVES

It was the aim of this study to investigate the long-term value of transesophageal atrial pacing in predicting death in patients with known or suspected coronary artery disease.

BACKGROUND

Exercise, dobutamine and dipyridamole stress echocardiography are all effective in predicting cardiac death. Transesophageal atrial pacing stress echocardiography (TAPSE) is a safe alternative to pharmacologic tests, but no information is available on prognosis with TAPSE.

METHODS

One thousand and ten TAPSE were performed in 975 consecutive patients. TAPSE was feasible in 970 tests (96%); after exclusion of the 35 patients with more than 1 TAPSE and those 42 lost at follow-up (mean 4.5 +/- 3.7 years, median 6 years), the final population consisted of 857 patients (675 males, 58 +/- 9 years old). The Cox model was used to analyze the association of clinical, resting and TAPSE variables with cardiac death.

RESULTS

TAPSE was abnormal in 281 (32%) patients. There were 46 cardiac-related deaths (5%), 25 among the 281 patients with an abnormal test (8.9%) and 21 among the 576 patients with a normal test (3.6%). The predictors of cardiac death were age, previous revascularization, resting wall motion score index and its variation during TAPSE. Abnormal TAPSE significantly increases the value of models predicting cardiac death. Moreover, cardiac mortality increased progressively with the extent of the induced ischemia.

CONCLUSIONS

TAPSE is a useful tool in predicting death in patients with known or suspected coronary artery disease and might be considered an alternative to pharmacologic stressors.

Head to head comparison between perfusion and function during accelerated high-dose dipyridamole magnetic resonance stress for the detection of coronary artery disease

The aim of this study was to compare the diagnostic accuracy of perfusion and wall motion (WM) during dipyridamole magnetic resonance in patients with chest pain syndrome. Ninety-three patients with normal baseline left ventricular function were referred for coronary angiography. Additional dipyridamole stress magnetic resonance testing (0.84 mg/kg over 6 minutes; using a Signa Cvi scanner) was performed. Cardiac-gated fast gradient-echo train sequences with a first pass of gadolinium contrast medium were used to assess myocardial perfusion. A perfusion reserve index was calculated as the ratio of dipyridamole to rest upslope. A perfusion reserve index value <1.54 in 2 contiguous myocardial segments was the perfusion positivity criterion. The WM positivity criterion was a segmental score increase of > or =1 grade in > or =2 segments. WM and the perfusion reserve index showed similar diagnostic accuracy for >50% quantitatively assessed coronary diameter reduction (86% for both), with WM having higher specificity (96% vs 66%, p <0.01) and lower sensitivity (82% vs 93%, p <0.05) than the perfusion reserve index. Perfusion had the highest accuracy values for coronary stenoses <75% (cutoff 59%) and WM for coronary stenoses > or =75% (cutoff 84%) (p <0.001). In conclusion, during dipyridamole magnetic resonance stress testing, perfusion and WM abnormalities have similar diagnostic accuracy, with perfusion showing higher sensitivity, particularly in the detection of moderate stenoses, and WM showing higher specificity.

Comparison of prognostic value of pharmacologic stress echocardiography in chest pain patients with versus without diabetes mellitus and positive exercise electrocardiography

The aim of this study was to compare the prognostic value of pharmacologic stress echocardiography in diabetic and nondiabetic patients with chest pain and intermediate- to high-threshold positive exercise electrocardiographic results. A total of 935 patients with chest pain (131 diabetic patients) with ST-segment depression > or =1 mm on exercise electrocardiography at > or =75-W workload underwent dipyridamole (n = 786) or dobutamine (n = 149) stress echocardiography and were followed up for the occurence of hard (death and infarction) and major events (death, infarction, and late revascularization). During a median follow-up of 26 months, 158 events (51 deaths, 28 myocardial infarctions, and 79 late revascularizations) occurred: 34 in diabetic and 124 in nondiabetic patients (26% vs 15%, p = 0.003). Independent predictors of hard events were age, diabetes, and ischemia at stress echocardiography. Five-year hard event rates were 24% in patients with and 4% in those without ischemia (p <0.0001). Independent predictors of major events were age, diabetes, hypercholesterolemia, smoking habit, antianginal therapy at the time of testing, and ischemia at stress echocardiography. Five-year major event rates were 46% in patients with and 7% in those without ischemia (p <0.0001). Stress echocardiography results yielded effective prognostic information in diabetic and nondiabetic patients. However, the latter had worse outcomes in both the presence and absence of ischemia. Nevertheless, a nonischemic test result predicted an uneventful 6-month period and 2% major event rate at 1-year follow-up in both populations. In conclusion, stress echocardiography was effective in risk stratifying diabetic and nondiabetic patients with intermediate- to high-threshold ischemic exercise electrocardiographic results. However, major event rates associated with a nonischemic test result were similar in diabetic and nondiabetic patients during the first year of follow-up and markedly increased in the former thereafter.

Cardiac functional stress imaging: a sequential approach with stress echo and cardiovascular magnetic resonance

AIMS

The aim of the study was to assess the feasibility and accuracy of an integrated stress imaging algorithm with echo first and second-line Cardiac Magnetic Resonance (CMR) in selected cases. Stress echo (SE) is widely used for non-invasive diagnosis of coronary artery disease (CAD), but difficult patients and ambiguous responses may be met even with top-level technology and expertise. CMR might ideally complement SE in well-selected cases with unfeasible and/or ambiguous and/or submaximal results.

METHODS AND RESULTS

152 in-hospital patients with chest pain and normal baseline function were referred for SE and coronary angiography. Of the initial population, 33 were shunted to CMR due to poor acoustic window or ambiguous or submaximal SE test. The only criterion of positivity for both techniques was the presence of regional wall motion abnormalities in at least 2 contiguous segments. Coronary angiography was performed independently of test results. Significant CAD was identified by a >50% quantitatively assessed diameter reduction in at least 1 major coronary vessel.CAD was present in 88 patients. Interpretable and diagnostic stress test were obtained in 143 patients with the sequential algorithm. The sequential (SE in 110 + CMR in 33 patients) algorithm showed a sensitivity of 76% (95% CI 66% to 85%) specificity of 87% (95% CI 76% to 95%) and accuracy of 80% (95% CI 73% to 86%).

CONCLUSION

A sequential functional stress imaging algorithm with stress echo first and stress CMR in selected cases is feasible, clinically realistic and allows an efficient, radiation-free diagnosis of CAD.

Prognostic value of coronary flow reserve in medically treated patients with left anterior descending coronary disease with stenosis 51% to 75% in diameter

According to American College of Cardiology/American Heart Association/Society for Cardiovascular Angiography and Interventions 2005 guidelines on percutaneous intervention, intracoronary physiologic measurement in the assessment of effects of intermediate coronary stenoses in patients with anginal symptoms is a class IIa indication. This study assessed the additional prognostic value of Doppler echocardiographically derived coronary flow reserve (CFR) in patients with single-vessel disease and intermediate stenosis severity. We enrolled 86 patients (44 men; 66 +/- 10 years of age) with angiographically assessed single-vessel coronary artery disease of the left anterior descending coronary artery (LAD) with quantitatively assessed diameter stenosis severity 50% to 75%. All patients underwent dipyridamole (up to 0.84 mg/kg over 6 minutes) stress echocardiography with wall motion analysis by 2-dimensional echocardiography and CFR evaluation of the affected artery by Doppler. All patients were followed up for a median of 14 months (first quartile 10, third quartile 18) after diagnostic coronary angiography (without percutaneous intervention for a clinically driven decision). Mean diameter stenosis of the LAD was 58 +/- 10%. Mean CFR of the LAD was 2.09 +/- 0.5. Regional wall motion abnormality at peak stress was present in 17 patients. During follow-up, 24 events occurred: 6 nonfatal ST-elevation myocardial infarctions and 18 non-ST-elevation myocardial infarctions. Thirty-month spontaneous event-free survival was higher in patients with normal CFR and lower in patients with decreased CFR (86% vs 30%, p = 0.0001). At Cox analysis, a CFR <2 (hazard ratio 24.2, 95% confidence interval 3.2 to 179.7, p = 0.002) was the only independent prognostic predictor of outcome. In conclusion, in medically treated patients with single-vessel disease of intermediate severity, decreased CFR is associated with a worse outcome.

Additional prognostic value of coronary flow reserve in diabetic and nondiabetic patients with negative dipyridamole stress echocardiography by wall motion criteria

OBJECTIVES

The aim of this prospective, multicenter, observational study was to compare the prognostic value of Doppler echocardiographic-derived coronary flow reserve (CFR) in diabetic and nondiabetic patients with known or suspected coronary artery disease and negative dipyridamole stress echocardiography.

BACKGROUND

The prognostic value of CFR in diabetic patients with negative stress echocardiography remains unknown.

METHODS

The study group consisted of 1,130 patients (207 diabetics) with known (n = 418) or suspected (n = 712) coronary artery disease and negative stress echocardiography by wall motion criteria. All underwent dipyridamole (up to 0.84 mg/kg over 6 min) echocardiography with CFR evaluation of left anterior descending artery by Doppler. A value of CFR < or =2.0 was considered abnormal.

RESULTS

Coronary flow reserve was abnormal in 309 (27%) patients. During a median follow-up of 16 months, 98 events (8 deaths, 24 ST-segment elevation myocardial infarctions, and 66 non-ST-segment elevation myocardial infarctions) occurred. In addition, 101 patients underwent revascularization and were censored. Multivariable prognostic indicators were abnormal CFR (p < 0.0001), anti-ischemic therapy at the time of testing (p = 0.002), age (p = 0.02), and resting wall motion abnormality (p = 0.05). The event rate was markedly higher (p < 0.0001) for both diabetic and nondiabetic patients with abnormal CFR as compared with diabetic and nondiabetic patients with normal CFR. Of note, a preserved CFR off therapy identified diabetic and nondiabetic patients with better survival and comparable yearly event rates (2.2% vs. 2.0%, p = 0.80).

CONCLUSIONS

Coronary flow reserve provides independent prognostic information in diabetic and nondiabetic patients with known or suspected coronary artery disease and negative dipyridamole stress echocardiography. In particular, a normal CFR off therapy is associated with better and similar survival in the 2 populations.

Physiological roles of vascular nucleoside transporters

Nucleoside transporters (NTs) comprise 2 widely expressed families, the equilibrative nucleoside transporters (diffusion-limited channels) and concentrative nucleoside transporters (sodium-dependent transporters). Because of their anatomic position at the blood-tissue interface, vascular NTs are in an ideal position to influence vascular nucleoside levels, particularly adenosine, which among others plays an important role in tissue protection during acute injury. For example, endothelial NTs contribute to preserving the vascular integrity during conditions of limited oxygen availability (hypoxia). Indeed, hypoxia-inducible factor-1-dependent repression of NTs results in enhanced extracellular adenosine signaling and thus attenuates hypoxia-associated increases in vascular leakage. In addition, vascular NTs also contribute to cardiac ischemic preconditioning, coronary vasodilation, and inhibition of platelet aggregation. Moreover, vascular nucleoside uptake via NTs is important for nucleoside recovery, particularly in cells lacking de novo nucleotide synthesis pathways (erythrocytes, leukocytes). Taken together, vascular NTs are critical in modulating adenosine-mediated responses during conditions such as inflammation or hypoxia.

Hemodynamic responses and long-term follow-up results in patients using chronic beta 1-selective and nonselective beta-blockers during dobutamine stress echocardiography

OBJECTIVE

This study was undertaken to determine to what extent hemodynamic responses to dobutamine infusion between patients using concomitant beta1-selective or nonselective beta-blockers differ and whether this difference affects the long-term prognostic value of dobutamine stress echocardiography with respect to cardiac events.

DESIGN

Single center, observational study.

METHODS

A total of 1234 patients using chronic beta-blockers underwent dobutamine stress echocardiography and were prospectively included in the study. Heart rate and blood pressure responses were measured during the dobutamine stress echocardiography protocol. During a median follow-up time of 4 years (range: 0.5-14 years), overall and cardiac mortality and nonfatal myocardial infarction were noted.

RESULTS

A total of 954 and 280 patients were using beta1-selective and nonselective beta-blockers, respectively. During dobutamine stress echocardiography, the heart rate response was significantly higher, systolic and diastolic blood pressure responses were significantly lower and the double product of heart rate and systolic blood pressure was similar in patients using beta1-selective than in patients using nonselective beta-blockers. In patients with and without new wall motion abnormalities during dobutamine stress echocardiography, a similar cardiac event-free survival was observed irrespective of the selectivity of beta-blockers (P=0.9 and 0.3, respectively).

CONCLUSION

During dobutamine stress echocardiography, heart rate and blood pressure response was different, but the double product was similar in patients using beta1-selective or nonselective beta-blockers, which may explain why the long-term prognostic value of dobutamine stress echocardiography is similar in these two groups.

Coronary flow reserve evaluation in stress-echocardiography laboratory

The assessment of coronary flow reserve by transthoracic echocardiography has recently been introduced into clinical practice with good results for the diagnosis of left anterior descending artery disease and fairly promising results for posterior descending coronary artery disease. By looking at what is behind wall motion, we may realize a sonographer's dream and, in particular, the addition of coronary flow reserve to regional wall motion analysis allows us to have - in the same sitting - high specificity (regional wall motion) and a highly sensitive (coronary flow reserve) diagnostic marker, with an improvement in overall diagnostic accuracy. Coronary flow reserve evaluation may shift the balance of stress choice in favor of vasodilators, which are easier to perform with dual imaging than dobutamine or exercise coronary flow reserve evaluation and may shift the choice in favor of dipyridamole or adenosine stress tests, which are also easier to perform with dual imaging than those using dobutamine or exercise. Lastly, it adds quantitative support to the exquisitely qualitative assessment of wall motion analysis, thereby facilitating the communication of stress echo results to the cardiological world outside the echo laboratory.

Recruitment of aged donor heart with pharmacological stress echo. A case report

Background

The heart transplant is a treatment of the heart failure, which is not responding to medications, and its efficiency is already proved: unfortunately, organ donation is a limiting step of this life-saving procedure.

To counteract heart donor shortage, we should screen aged potential donor hearts for initial cardiomyopathy and functionally significant coronary artery disease.

Donors with a history of cardiac disease are generally excluded. Coronary angiography is recommended for most male donors older than 45 years and female donors older than 50 years to evaluate coronary artery stenoses. A simpler way to screen aged potential donor hearts for initial cardiomyopathy and functionally significant coronary artery disease should be stress echocardiography.

Case report

A marginal donor (A 57 year old woman meeting legal requirements for brain death) underwent a transesophageal (TE) Dipyridamole stress echo (6 minutes accelerated protocol) to rule out moderate or severe heart and coronary artery disease. Wall motion was normal at baseline and at peak stress (WMSI = 1 at baseline and peak stress, without signs of stress inducible ischemia). The pressure/volume ratio was 9.6 mmHg/ml/m² at baseline, increasing to 14 mmHg/ml/m² at peak stress, demonstrating absence of latent myocardial dysfunction.

The marginal donor heart was transplanted to a recipient "marginal" for co-morbidity ( a 63 year old man with multiple myeloma and cardiac amyloidosis , chronic severe heart failure, NYHA class IV).

Postoperative treatment and early immunosuppressant regimen were performed according to standard protocols.

The transplanted heart was assessed normal for dimensions and ventricular function at transthoracic (TT) echocardiography on post-transplant day 7.

Coronary artery disease was ruled out at coronary angiography one month after transplant; left ventriculography showed normal global and segmental LV function of the transplanted heart.

Conclusion

For the first time stress echo was successfully used in the critical theater of screening potential donor hearts. This method is enormously more feasible, less expensive, and more environmentally sustainable than any possible alternative strategy based on stress scintigraphy perfusion imaging or coronary angiography. The selection of hearts "too good to die" on the basis of bedside resting and stress echo can be a critical way to solve the mismatch between donor need and supply.

The additional prognostic value of coronary flow reserve on left anterior descending artery in patients with negative stress echo by wall motion criteria. A Transthoracic Vasodilator Stress Echocardiography Study

BACKGROUND

Vasodilator stress echocardiography allows imaging of left anterior descending (LAD) coronary flow reserve (CFR), which may provide additional prognostic information over regional wall motion.

AIM

To assess the prognostic value of CFR in patients with known or suspected coronary artery disease (CAD) and negative stress echo.

METHODS

We studied 329 consecutive patients (193 men, age 61 +/- 13 years) with known (n = 101) or suspected (n = 228) CAD and negative stress echo by standard wall motion criteria. All patients underwent dipyridamole (up to 0.84 mg/kg in 10 minutes) stress echo with CFR evaluation of LAD by Doppler.

RESULTS

During follow-up (28 +/- 10 months), 22 events occurred: 1 cardiac death, 6 nonfatal myocardial infarctions, 5 unstable anginas, and 10 late (> 6 months) coronary revascularizations. Moreover, 9 patients underwent early (< 6 months) revascularization and were censored. Using a receiver operating characteristic analysis, CFR < or = 1.92 was the best predictor of future events (area under the curve = 0.80, sensitivity = 77%, specificity = 85%) and was taken as criterion for reduced CFR accordingly. Sixty-three (19%) patients had reduced and 266 (81%) had normal CFR on LAD. The 36-month event-free survival was higher in patients with normal and lower in patients with reduced CFR (98% vs 64%, P < .0001). At Cox analysis, CFR of LAD (hazard ratio [HR] 16.52, 95% CI 5.76-47.40, P < .0001), left ventricular mass index (HR 1.03 per unit increment, 95% CI 1.00-1.05, P = .01), and smoking habit (HR 3.00, 95% CI 1.24-7.23, P = .01) were independent prognostic indicators. Using an interactive stepwise procedure, CFR on LAD provided additional prognostic information to clinical, resting echo, and angiographic findings.

CONCLUSIONS

In patients with known or suspected CAD and negative stress echocardiography by wall motion criteria, CFR provides independent information for prognostic stratification, and a reduced CFR is associated with a less benign long-term outcome.

Clinical and prognostic implications of angina pectoris developing during dobutamine stress echocardiography in the absence of inducible wall motion abnormalities

This study assessed the incidence, clinical correlates, and prognostic significance of angina during dobutamine stress echocardiography (DSE) in patients who did not have inducible wall motion abnormalities. We studied 2,117 patients (61 +/- 13 years of age; 1,149 men) who underwent large-dose DSE and had no new or worsening wall motion abnormalities during DSE. Follow-up events were hard cardiac events (cardiac death or nonfatal myocardial infarction) and myocardial revascularization. Angina was induced in 217 patients (10%) during stress. DSE was normal in 1,198 patients (57%), whereas 919 patients (43%) had fixed wall motion abnormalities. During a mean follow-up of 5.5 +/- 3.7 years, 143 patients (7%) died of cardiac causes and 78 (4%) had nonfatal myocardial infarction. Patients who developed angina during DSE were more likely to have a history of exertional angina (64% vs 16%, p <0.001) and had a higher wall motion score index at rest (1.29 +/- 0.5 vs 1.17 +/- 0.4, p = 0.01) compared with patients who did not have angina. Annual hard cardiac event rates were 2.2% in patients who had dobutamine-induced angina (DIA) and 2.1% in patients who did not (p = NS). Myocardial revascularization was performed more frequently in patients who had DIA than in those who did not (39% vs 14%, p <0.0001). In Cox's regression model, independent predictors of hard events were age (RR 1.03, 95% confidence interval [CI] 1.02 to 1.04), male gender (RR 1.6, 95% CI 1.1 to 2.2), smoking (RR 1.5, 95% CI 1.1 to 2.9), and wall motion score index at rest (RR 2.6, 95% CI 1.8 to 3.8). In conclusion, in patients who do not have ischemia by echocardiographic criteria during DSE, inducible angina pectoris is associated with a high incidence of revascularization during follow-up. However, the hard cardiac event rate does not differ in patients who develop DIA from those who do not.

Vascular surgery patients: perioperative and long-term risk according to the ACC/AHA guidelines, the additive role of post-operative troponin elevation

AIMS

The objectives of this study are to evaluate the prognostic role of pre-operative stratification in patients undergoing elective major vascular surgery, the timing of adverse outcomes, and the predictive role of troponin (cTn).

METHODS AND RESULTS

Consecutive vascular surgery candidates (n=391) were prospectively stratified and treated according to the ACC/AHA guidelines. The patients were categorized into three groups: (1) with coronary revascularization in the past 5 years, (2) with intermediate clinical risk predictors, and (3) with minor or no clinical risk predictors. cTnI was measured post-operatively. By 18 months, 18.7% of subjects had experienced death or acute myocardial infarction (MI) (by the ACC/ESC criteria). The hazard ratio (HR) was 5.21 (95% CI=2.60-10.43; P<0.0001) in group 1 and 2.58 (95% CI=1.27-4.38; P=0.004) in group 2 when compared with group 3. Most events occurred within 30 days. Elevations of cTnI were associated with adverse outcomes even after multivariable adjustment at long-term (adjusted overall HR=4.73, 95% CI=2.92-7.65; P<0.0001) and at 30 days (adjusted HR=5.52, 95% CI=3.23-9.42; P<0.0001).

CONCLUSION

After pre-operative stratification, patients undergoing elective major vascular surgery remain at high risk of MI and death. Events occur mainly early after surgery. cTnI elevations are frequent and independently associated with increased risk. These findings suggest the need for a major re-evaluation of our approach to these patients.

Coronary flow reserve in stress-echo lab. From pathophysiologic toy to diagnostic tool

The assessment of coronary flow reserve by transthoracic echocardiography has recently been introduced into clinical practice with gratifying results for the diagnosis of left anterior descending artery disease simultaneously reported by several independent laboratories. This technological novelty is changing the practice of stress echo for 3 main reasons. First, adding coronary flow reserve to regional wall motion allows us to have - in the same sitting - high specificity (regional wall motion) and a high sensitivity (coronary flow reserve) diagnostic marker, with an obvious improvement in overall diagnostic accuracy. Second, the technicalities of coronary flow reserve shift the balance of stress choice in favour of vasodilators, which are a more robust hyperemic stress and are substantially easier to perform with dual imaging than dobutamine or exercise. Third, the coronary flow reserve adds a quantitative support to the exquisitely qualitative assessment of wall motion analysis, thereby facilitating the communication of stress echo results to the cardiological world outside the echo lab. The next challenges involve the need to expand the exploration of coronary flow reserve to the right and circumflex coronary artery and to prove the additional prognostic value - if any - of coronary flow reserve over regional wall motion analysis, which remains the cornerstone of clinically-driven diagnosis in the stress echo lab.

Anti-ischemic therapy and stress testing: pathophysiologic, diagnostic and prognostic implications

Anti-ischemic therapy, in particular beta-blockers, is the most commonly employed drug for the control of myocardial ischemia in patients with stable coronary artery disease. Its widespread use also in patients with suspected coronary artery disease has important practical, clinical diagnostic and prognostic implications because diagnostic tests are heavily influenced by its effects. In the present review, the pathophysiological mechanisms of ischemia protection by antianginal therapy are described. Not all stressors are created equal in front of the different classes of antianginal drugs and on their turn the different classes of drugs exert different levels of protection on inducible ischemia. Several clinical implications can be drawn: From the diagnostic viewpoint antianginal therapy decreases test sensitivity, offsetting the real ischemic burden for a too high percentage of false negative tests. From the prognostic viewpoint test positivity in medical therapy identifies a group of subjects at higher risk of experiencing cardiac death and positivity on medical therapy can be considered a parameter of ischemia severity. Nonetheless in patients with known coronary artery disease the ability of antianginal therapy to modify the ischemic threshold at stress testing represent a powerful means to assess therapy efficacy. From a practical viewpoint, the use of antianginal therapy at time of testing has advantages and disadvantages which are largely dependent on the purpose a test is performed: if the purpose of testing is to diagnose ischemia, it should be performed in the absence of antianginal medications. If the purpose of testing is to assess the protective effects of antianginal therapy, the test should be performed on medications.