Abnormal Coronary Flow Reserve Research Articles

Incremental prognostic value of coronary flow reserve assessed with single-photon emission computed tomography

BackgroundWe assessed the prognostic value of coronary flow reserve (CFR) estimated by single-photon emission computed tomography (SPECT) in patients with suspected myocardial ischemia. Methods and ResultsMyocardial perfusion and CFR were assessed in 106 patients using dipyridamole/rest Tc-99m sestamibi SPECT and follow-up was obtained in 103 (97%) patients. Four early revascularized patients were excluded and 99 were assigned to normal (summed stress score <3) vs abnormal myocardial perfusion and to normal (≥2.0) vs abnormal CFR. During the follow-up (5.8 ± 2.1 years), 28 patients experienced a cardiac event (cardiac death, nonfatal myocardial infarction, and late revascularization). Abnormal perfusion (P < .01) and abnormal CFR (P < .05) were independent predictors of cardiac events at Cox proportional hazard regression analysis. Also in patients with normal perfusion, abnormal CFR was associated with a higher annual event rate compared with normal CFR (5.2% vs 0.7%; P < .05). CFR data improved the prognostic power of the model including clinical and myocardial perfusion data increasing the global chi-square from 18.6 to 22.8 (P < .05). Finally, at parametric survival analysis, in patients with normal perfusion the time to achieve ≥2% risk of events was >60 months in those with normal and <12 months in those with abnormal CFR. ConclusionsMyocardial perfusion findings and CFR at SPECT imaging are both independent predictors of cardiac events. Estimated CFR provides incremental prognostic information over those obtained from clinical and myocardial perfusion data, particularly in patients with normal perfusion findings.

Inflammation is Related to Coronary Flow Reserve Detected by Positron Emission Tomography in Asymptomatic Male Twins

This study sought to examine the relationship between inflammation and coronary microvascular function in asymptomatic individuals using positron emission tomography (PET) and assessment of coronary flow reserve (CFR). Coronary microvascular dysfunction is an early precursor of coronary artery disease (CAD) thought to result from endothelial cell activation and inflammation, but data are limited. We examined 268 asymptomatic male monozygotic and dizygotic twins. Plasma biomarkers of inflammation and endothelial cell activation included C-reactive protein (CRP), interleukin (IL)-6, white blood cell count (WBC), vascular cell adhesion molecule (VCAM)-1, and intercellular adhesion molecule (ICAM)-1. Blood flow quantitation was obtained with [¹³N] ammonia PET at rest and after adenosine stress. CFR was measured as the ratio of maximum flow to baseline flow at rest; abnormal CFR was defined as a ratio < 2.5. A summed stress score for visible perfusion defects was calculated. In within-pair analyses, all biomarkers, except VCAM-1, were higher in twins with lower CFR than their brothers with higher CFR (p < 0.05). This was observed in the entire sample, as well as within pairs discordant for a CFR of <2.5. Associations persisted after adjusting for summed stress score and CAD risk factors. In contrast no biomarker, except IL-6, was related to the summed stress score of visible defects. Even in asymptomatic subjects, a decrease in coronary microvascular function is accompanied by a systemic inflammatory response, independent of CAD risk factors. Our results, using a controlled twin design, highlight the importance of coronary microvascular function in the early phases of CAD.

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.

Cardiac syndrome X

Cardiac syndrome X (CSX) is a clinical condition characterized by the presence of typical exertional chest pain, a positive response to exercise stress testing, and normal coronary angiograms. The exact mechanism of CSX is not known and multiple pathophysiologic abnormalities have been reported in patients with CSX, including abnormal coronary flow reserve, insulin resistance, abnormal autonomic control, enhanced sodium–hydrogen exchange activity, abnormal cardiac sensitivity, and microvascular spasm [1].

Prognostic Value of Left and Right Coronary Flow Reserve Assessment in Nonischemic Dilated Cardiomyopathy by Transthoracic Doppler Echocardiography

Background Coronary flow reserve (CFR) in the left anterior descending artery (LAD) can be reduced in nonischemic dilated cardiomyopathy (DCM). The aim of this study was to assess the prognostic value of CFR in LAD and in the posterior descending artery (PD) in DCM patients. Methods Seventy-two DCM patients (44 men, mean age 64 ± 13 years) underwent dipyridamole (0.84 mg/kg in 6 minutes) stress echo. CFR was defined as the ratio between maximal vasodilation and rest peak diastolic flow velocity in LAD and PD. Results CFR was abnormal in LAD in 42 out of 72 patients and in PD in 31 out of 55. All patients completed the clinical follow-up, and 56 patients completed the echocardiographic follow-up. During median follow-up of 42 months, 33 events (7 deaths, 26 major cardiac events) occurred. Event rate was markedly higher for patients with reduced CFR compared with DCM patients with normal CRF in LAD (0 vs 19 events; P < .001) and in PD (1 vs 13 events; P < .001). CFR in LAD and in PD were significantly related to the change in end-systolic volume during follow-up ( r = −0.481, P < .001; and r = −0.407, P = .028; respectively). Preserved CFR in both LAD and PD was associated with better ( P < .0001) event-free survival compared with abnormal CFR (log rank: 28.1; P < .0001). Conclusions In DCM patients, impairment of CFR in LAD and PD is related to a worse outcome; CFR impairment is more relevant when it occurs in LAD. PD evaluation may be redundant and time-consuming, because the additive value is small and the feasibility suboptimal.

Persistent Abnormal Coronary Flow Reserve in Association with Abnormal Glucose Metabolism Affects Prognosis in Acute Myocardial Infarction

To evaluate changes in coronary flow reserve (CFR) over time after acute myocardial infarction (AMI) in relation to left ventricular (LV) function and glucometabolic state and prognostic implication of abnormal CFR. 154 patients with first time AMI had a comprehensive assessment of the LV function and CFR at baseline and after 3 months of follow-up. CFR was measured noninvasively in left descending artery by transthoracic echocardiography. Eighty-five patients had an abnormal CFR at baseline. At baseline patients with persistently normal CFR had higher wall motion score index (WMI), ejection fraction (EF) and S' compared with patients with abnormal CFR. At follow-up patients with persistently normal CFR had higher WMI, EF, S' and lower end-systolic diameter compared with patients with abnormal microcirculation. Performing univariate logistical regression baseline CFR (P = 0.004), S' (P = 0.045) and abnormal glucose metabolism (P = 0.001) were predictors of a decreased CFR at 3 months of follow-up. In multivariate analyses abnormal glucose metabolism (OR: 5.3; 95%CI: 1.9-14.4; P = 0.001) remained a predictor of decreased CFR at follow-up, furthermore baseline CFR (OR: 0.5; 95%CI: 0.25-0.94; P = 0.032) and S' (OR: 0.67; 95% CI: 0.47-0.94; P = 0.021) was predictors of decreased CFR. Finally, CFR was associated with a lower risk of cardiac events in patients with normal glucose metabolism (HR: 0.64; 95% CI: 0.22-1.9; P = 0.42) than in patients with abnormal glucose metabolism (HR: 2.9; 95% CI: 1.1-7.6; P = 0.03), suggesting significant effect modification (Pinteraction = 0.03). Abnormal glucose metabolism is associated with poorer recovery of microvascular integrity after AMI. In addition, there seem to exist a prognostic interaction between glucometabolic state and abnormal CFR.

Coronary flow reserve is impaired in patients with nonalcoholic fatty liver disease: Association with liver fibrosis

BackgroundNonalcoholic fatty liver disease (NAFLD) is associated with an increased risk of cardiovascular disease. Coronary flow reserve (CFR) is widely used to examine the integrity of coronary microvascular circulation. We evaluated the prevalence of impaired CFR in patients with biopsy-proven NAFLD. We also investigated the independent clinical, biochemical, and liver histology predictors of CFR in the setting of NAFLD. MethodsFifty-nine consecutive patients with NAFLD and 77 age- and gender-matched controls were evaluated. CFR recordings were performed by transthoracic Doppler harmonic echocardiography. CFR≥2.0 was considered normal. ResultsCFR was significantly lower in patients with NAFLD than in controls (2.11±0.45 vs. 2.52±0.62, P<0.001). An impaired CFR (i.e. <2) was found in 25 NAFLD patients (42.4%) whereas all controls had normal CFR values (P<0.001). A stepwise linear regression analysis in NAFLD patients identified liver fibrosis scores as the only independent predictor of CFR values (β=−0.60; t=−2.44, P=0.021). ConclusionOur findings indicate that in patients with biopsy-proven NAFLD: (a) an abnormal CFR is found in approximately 42.4% of cases, and (b) liver fibrosis scores are an independent predictor of depressed CFR.

Abstract 5518: Abnormal Coronary Flow Reserve is Related to Impairment of Left Ventricular Function During Adenosine Stress Echocardiography in Untreated Hypertensive Patients

Objective: Coronary microcirculation is disturbed in hypertensive patients. We investigated the effects of coronary flow reserve (CFR) on the response of Left Ventricular (LV) systolic and diastolic function as assessed by Tissue Doppler Imaging during adenosine stress echocardiography in never-treated hypertensive patients. Methods: We studied 43 patients (mean age: 53±12 years), with untreated arterial hypertension (clinic blood pressure &gt;140/90 mmHg and &gt;125/80 mmHg in 24hour ambulatory BP monitoring) by adenosine stress echocardiography and 22 healthy controls matched for sex, age and atherosclerotic factors. We measured: time integral (VTI-Vd) of diastolic (Vd) coronary blood flow velocity by transthoracic Doppler echocardiography of the LAD Ratio of VTI-Vd after adenosine infusion (140 μ g/kg/min) to VTI-Vd at baseline to assess CFR E and A doppler, Sm, Em, Am lateral mitral annulus velocities with TDI, Em/Am ratio and E/Em ratio before and during adenosine infusion to assess LV systolic and diastolic function, the percent % changes of the measured indices between baseline and peak adenosine infusion. Results: All patients had normal baseline ejection fraction. Compared to controls, hypertensives had lower CFR (2.3±0.7 vs. 2.9±0.9, p=0.03). At baseline, hypertensives compared to controls, had lower Em/Am ratio (0.9±0.3 vs. 1.3±0.4, p=0.002), Sm (8.7±1.7 vs. 9.7±2.6, p=0.07), Em (10.1±2.8 vs 12.1±3.5, p=0.03) and higher Am (11.1±2.5 vs. 9.5±2.0, p=0.03). At peak adenosine infusion there were an increase in Sm, Em and Am in all patients (p&lt;0.05). Furthermore a decreasing CFR was associated with a decreasing Em (r= 0.46, p=0.05), Em/Am (r=0.49, p=0.048) and increasing E/Em (r=−0.4, p=0.04). A reduced CFR was related with a smaller % increase of Sm (r= −0.40, p=0.049), % increase of Em (r=− 0.5, p=0.033) and higher % increase of E/Em (r=−.42, p=0.04) at peak stress. Patients with CFR&lt;2.5 (n=28), compared to those with CFR≥2.5 had lower % change of Sm (27±20% vs. 51±34% p=0.04), % change of Em (8±3% vs. 46 ±3%, p=0.05) and higher % increase of E/Em (24±3% vs −1±2%, p=0.04). Conclusions: An abnormal response of LV function during adenosine stress echocardiography is related with impaired CFR in untreated hypertensive patients.

Abstract 5510: Inflammation is Related to Coronary Flow Reserve Detected by Positron Emission Tomography in Healthy Twins

Introduction. Coronary microvascular dysfunction is an early precursor of CAD and is thought to result from endothelial cell activation and inflammation. Coronary flow reserve (CFR) is an index of microvascular dysfunction, but limited and conflicting data exist on the relationship between CFR and inflammation. Methods. We examined 292 healthy male twins selected from the Vietnam Era Twin Registry. Plasma biomarkers of inflammation and endothelial cell activation were assessed and included C-reactive protein (CRP), interleukin-6 (IL-6), total white blood cell count (WBC), sVCAM-1 and sICAM-1. We performed myocardial perfusion imaging and blood flow quantitation with [13N] ammonia positron emission tomography at rest and after adenosine stress. CFR was measured as the ratio of maximum flow to baseline flow at rest averaged across 20 myocardial regions; abnormal CFR was defined as &lt;2.5. A summed stress score for visible perfusion defects was also calculated. Traditional CAD risk factors were also measured. Mixed-effect and GEE models were used to conduct matched-pair analyses. Results. The twins had a mean age of 54 and 57% were monozygotic. In the overall sample, all biomarkers except sVCAM-1 were significantly correlated with CFR. In contrast, only IL-6 was correlated with the summed stress score of visible defects. Of 146 twin pairs, 138 were discordant for CFR (using no cutpoint) and 56 pairs were discordant for CFR &lt;2.5. Values of all biomarkers were higher in twins with lower CFR than their brothers with higher CFR (Table ). The associations persisted after adjusting for summed stress score and CAD risk factors; after stratifying by zygosity results were similar. Conclusions. Systemic inflammation and endothelial cell activation are associated with coronary microvascular dysfunction, independent of CAD risk factors. Our results using a highly controlled twin design highlight the importance of inflammatory processes in the early phases of CAD. Percent Higher Biomarker Level in Twin with Lower CFR Compared to Brother with Higher CFR This research has received full or partial funding support from the American Heart Association, National Center.

Influence of Abnormal Glucose Metabolism on Coronary Microvascular Function After a Recent Myocardial Infarction

This study sought to assess the association between abnormal glucose metabolism and abnormal coronary flow reserve (CFR) in patients with a recent acute myocardial infarction (AMI). Mortality and morbidity after AMI is high among patients with abnormal glucose metabolism, which may be related to abnormal microcirculation. We studied 183 patients with a first AMI. In 161 patients with no history of diabetes mellitus (DM), an oral glucose tolerance test was performed, and patients were categorized according to World Health Organization criteria for whole blood glucose into 3 groups. After coronary angiography and revascularization, a comprehensive transthoracic echocardiogram and noninvasive assessment of CFR was performed in the distal part of left descending artery, as an indicator of microvascular function. Adenosine was administered by intravenous infusion (140 microg/kg/min) to obtain the hyperemic flow profiles. The CFR was defined as the ratio of hyperemic to baseline peak diastolic coronary flow velocities. Median CFR was 1.9 (interquartile range [IQR] 1.4 to 2.4], and 109 (60%) patients had a CFR <or=2. The lowest CFR was seen in patients with a history of DM (1.4 [IQR 1.4 to 1.7], n = 22) and in patients with newly diagnosed DM (1.6 [IQR 1.3 to 2], n = 39), whereas CFR did not differ in patients with abnormal glucose tolerance (2.1 [IQR 1.4 to 2.6], n = 58) and in patients with normal glucose tolerance (2.2 [IQR 1.7 to 2.6], n = 62). In a stepwise logistic regression model adjusting for age, sex, site and size of AMI, heart rate, risk factors of the metabolic syndrome, degree of angiographic evidence of coronary artery disease, and medical therapy, newly diagnosed DM (odds ratio: 3.0) and a history of DM (odds ratio: 9.9) remained significant predictors of CFR <2, whereas impaired glucose tolerance was not. CFR is decreased in patients with known or newly diagnosed DM even after adjustment of possible confounders, whereas CFR in patients with impaired glucose tolerance seems less affected. (Coronary Flow Reserve and Glucometabolic State [CFRGS]; NCT00845468).

Myocardial Bridging

According to postmortem studies, coronary atherosclerosis can be substantial and reach a high prevalence of advanced lesions, including atheroma and fibroatheroma in young adults.1,2 Risk factors associated with coronary atherosclerosis such as dyslipidemia, smoking, diabetes mellitus, and hypertension have been identified. The development of atherosclerosis seems to be related to the magnitude and duration of exposure.3 Although research concentrates on identifying genetic markers in genome-wide association studies, there is still a lack of knowledge about the individual risk of developing coronary atherosclerosis.4 When atherosclerosis presents as acute coronary syndromes, mortality may be high.5 Plaque rupture and erosion have been identified as major underlying pathological-anatomic characteristics,6 but some suspect other mechanisms.7 In this issue of Circulation , Ishikawa et al8 present evidence that myocardial bridging may play a role as a congenital anatomic risk factor for coronary atherosclerosis and myocardial infarction. Article see p 376 Myocardial bridging results when myocardial tissue covers part of the left anterior descending coronary artery, resulting in a tunneled arterial segment, which can be regarded as a congenital variant.9–11 The prevalence is reported to be >50% at autopsy.12 Clinically, the diagnosis of myocardial bridging is established by coronary angiography demonstrating a systolic compression, described as a “milking effect,”13 but it was present in only <5% of cases recently in a large number of Chinese patients.14 When nitroglycerin was used as …

Long-Term Prognostic Value of 13N-Ammonia Myocardial Perfusion Positron Emission Tomography: Added Value of Coronary Flow Reserve

The goal of this study was to assess the predictive value of myocardial perfusion imaging with (13)N-ammonia positron emission tomography (PET) and coronary flow reserve (CFR) on long-term prognosis in patients with suspected myocardial ischemia. No prognostic data exist on the predictive value of CFR and (13)N-ammonia PET. Perfusion and CFR were assessed in 256 patients using (13)N-ammonia PET, and follow-up was obtained in 245 (96%) patients. Sixteen early revascularized patients were excluded and 229 were assigned to normal versus abnormal perfusion or normal versus abnormal CFR (<2.0). Major adverse cardiac events (MACE) (cardiac death, nonfatal myocardial infarction, late revascularization, or hospitalization for cardiac reasons) were assessed using the Kaplan-Meier method. Cox proportional hazard regression was used to identify independent predictors for cardiac events. During follow-up (5.4 +/- 2.2 years), 78 patients had at least 1 cardiac event, including 29 cardiac deaths. Abnormal perfusion (n = 126) was associated with a higher incidence of MACE (p < 0.001) and cardiac death (p < 0.05). In patients with normal perfusion, abnormal CFR was independently associated with a higher annual event rate over 3 years compared with normal CFR for MACE (1.4% vs. 6.3%; p < 0.05) and cardiac death (0.5% vs. 3.1%; p < 0.05). In abnormal perfusion, CFR remained predictive throughout the 10-year follow-up (p < 0.001). Perfusion findings in (13)N-ammonia PET and CFR are strong outcome predictors. CFR allows further risk stratification, suggesting a "warranty" period of 3 years if normal CFR is associated with normal perfusion. Conversely, in patients with abnormal perfusion, an impaired CFR has added value for predicting adverse outcomes.

Prognostic correlates of combined coronary flow reserve assessment on left anterior descending and right coronary artery in patients with negative stress echocardiography by wall motion criteria

Aims:To assess the prognostic correlates of Doppler echocardiographically derived coronary flow reserve (CFR) on two coronaries in patients with negative stress echo. Vasodilator stress echocardiography allows dual imaging of regional...

Additive Prognostic Value of Coronary Flow Reserve in Patients With Chest Pain Syndrome and Normal or Near-Normal Coronary Arteries

In patients with angiographically normal coronary arteries and chest pain, pharmacologic stress echocardiography can identify a subgroup of patients with a less benign prognosis. Coronary flow reserve (CFR) in the left anterior descending artery (LAD) can currently be combined with wall motion analysis during vasodilator stress echocardiography. The aim of this study was to assess the prognostic value of CFR response in patients with normal coronary arteries and normal wall motion during stress. We selected 394 patients (171 men, 61 +/- 11 years of age) who underwent dipyridamole stress echocardiography (0.84 mg/kg over 6 minutes) with 2-dimensional echocardiography and CFR evaluation of the LAD by Doppler. All had angiographically nonsignificant (<50% quantitatively assessed) stenosis in any major vessel, normal left ventricular function (wall motion score index 1), and test negativity for conventional wall motion criteria. Images were independently read by a core laboratory for wall motion and a core laboratory for CFR. Mean CFR was 2.5 +/- 0.6 and 87 patients (22%) had an abnormal CFR <2. During a median follow-up of 51 months, 31 events occurred, namely 4 deaths and 27 nonfatal myocardial infarctions (3 ST-elevated myocardial infarctions and 24 non-ST-elevated myocardial infarctions). Kaplan-Meier survival estimates for hard events showed a better outcome for those patients with a normal CFR compared with those with an abnormal CFR (96% vs 55%, p = 0.001, at 48 months of follow-up). In conclusion, in patients with angiographically normal or near-normal coronary arteries and preserved at-rest regional and global left ventricular function at baseline and during stress, CFR adds incremental value to the prognostic stratification achieved with clinical and angiographic data.

Prognostic Implications of Coronary Flow Reserve on Left Anterior Descending Coronary Artery in Hypertrophic Cardiomyopathy

The aim of the study was to prospectively evaluate a cohort of patients with hypertrophic cardiomyopathy (HC) after coronary flow reserve (CFR) assessment of the left anterior descending coronary artery. Sixty-eight patients with HC (40 men, mean +/- SD 58 +/- 12 years of age) underwent dipyridamole (up to 0.84 mg/kg over 6 minutes) echocardiography with CFR evaluation of the left anterior descending coronary artery by Doppler. Seventy-four age- and gender-matched, apparently healthy subjects served as controls. A CFR value <2.0 was considered abnormal. CFR was decreased in patients with HC versus controls (2.12 +/- 0.39 vs 2.78 +/- 0.58, p <0.0001). CFR was abnormal in 26 of 39 symptomatic and in 5 of 29 asymptomatic patients with HC (67% vs 17%, p <0.0001). In addition, patients with HC with left ventricular obstruction had decreased CFR (p <0.0001) compared with those without obstruction. During follow-up (22 +/- 13 months), 27 events occurred: 1 sudden death, 1 nonfatal myocardial infarction, 4 cardioverter-defibrillator implantations, 6 hospitalizations for heart failure, 5 unstable anginas, 2 syncopes, and 8 atrial fibrillations. Three-year event rate was markedly higher in patients with abnormal than in those with normal CFR (79% vs 17%, p <0.0001). Events were more frequent in symptomatic than in asymptomatic patients (62% vs 10%, p <0.0001). However, the latter had a 10-fold increased risk of events in the presence of abnormal CFR (40% vs 4%, p = 0.02). In conclusion, mean CFR is markedly lower in patients with HC than in apparently healthy subjects. Abnormal CFR is a strong and independent predictor of outcome in patients with HC.

The Future of Cardiovascular Imaging in the Diagnosis and Management of Heart Failure, Part 1

Radiographic, ultrasound, nuclear, and magnetic resonance methods have become indispensable in the management of heart failure (HF). Imaging is widely used in decision making in HF, not only in relation to left ventricular (LV) systolic and diastolic function but also in the selection of medical, device, and surgical therapy in HF and valvular heart disease. Future developments in the care of advanced heart disease, including stem cell therapy, device therapy to control remodeling, and percutaneous valve interventions, as well as the need to identify subclinical heart disease, are likely to expand this use. Moreover, the epidemic of diabesity (diabetes and obesity) will augment the existing epidemic of HF just when it appeared to have peaked.1 Large numbers of patients will need information from imaging to guide clinical decision making (Table 1). The sources of this information will need to be expeditious, inexpensive, and preferably objective and quantitative.2 View this table: Table 1. Established HF: What the Clinician Needs Although some of the measurements in HF patients are structural (LV mass and geometry), the main components of an imaging assessment in HF will continue to be primarily functional (LV ejection fraction, size, filling pressures, filling characteristics, and right ventricular [RV] function). A number of new technologies will enhance the future accuracy and reliability of these measures. ### LV Volumes and Ejection Fraction Routine techniques (contrast ventriculography, 2D echocardiography) provide real-time imaging in standard imaging planes. The only traditional method that has escaped this limitation has been radionuclide ventriculography, in which the ejection fraction is calculated from scintigraphic counts, but this introduces the separate potential problems of attenuation and overlying chambers. #### Limitations of 2D Imaging Two-dimensional imaging approaches require expert acquisition and observers and have limited reliability in obtaining appropriate cut planes in sequential studies. The limitation of requiring imaging planes in the correct axis is particularly an issue for 2D echocardiography, which …

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

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

Prognostic value of coronary flow reserve and aortic distensibility indices in patients with suspected coronary artery disease

In recent studies it has been demonstrated that a reduced coronary flow reserve (CFR) is independently associated with a less benign long-term outcome. Aortic stiffness is one of the most important cardiovascular risk factors predicting cardiovascular morbidity and mortality. Vasodilator stress transesophageal echocardiography (TEE) is a suitable method to evaluate simultaneously CFR and elastic properties of the descending thoracic aorta. The aim of the present study was to assess the relative prognostic value of simultaneously measured CFR and aortic elastic properties by pulsed-wave Doppler TEE in patients with suspected or known coronary artery disease (CAD). The study comprised 157 in-hospital patients with chest pain. In all patients, stress TEE was used for the simultaneous evaluation of CFR and aortic distensibility indices [elastic modulus E(p) and Young's circumferential static elastic modulus E(s)]. During a mean follow-up of 48 +/- 8 months, 13 patients suffered cardiovascular death. By univariate analysis older age, diabetes mellitus, increased left ventricular (LV) end-diastolic diameter, increased LV mass index, lower LV ejection fraction, and lower CFR were significant predictors of cardiovascular survival. Multivariate regression analysis showed that only CFR (hazard ratio [HR] 10.31, P = 0.04), age (HR 1.20, P = 0.001), and increased left ventricular (LV) end-diastolic diameter (HR 1.14, P = 0.02) were independent predictors of cardiovascular survival. Only in the small number of patients without CAD and abnormal CFR aortic distensibility seemed to provide complementary prognostic information over CFR. In the majority of patients aortic distensibility did not offer complementary prognostic information to CFR during vasodilator stress TEE testing.

Impact of Individual and Cumulative Coronary Risk Factors on Coronary Flow Reserve Assessed by Dobutamine Stress Echocardiography

Traditional cardiovascular risk factors have been shown to cause microvascular dysfunction. Most studies that have evaluated microcirculation rely on invasive measurement tools. We used dobutamine stress echocardiography, a validated method to measure coronary flow velocity (CFV) and coronary flow reserve (CFR), in a previously unstudied population without known significant coronary artery disease to determine the impact of traditional risk factors on CFR. Consecutive patients who had no evidence of regional wall motion abnormalities at rest or during dobutamine stress echocardiography were studied. Left anterior descending artery CFV was measured at baseline and at peak dobutamine stress and CFR was calculated as the ratio of peak stress CFV to baseline CFV. Fifty-nine consecutive patients (28 men) with mean age of 66.8+/-14.5 years were studied. CFR was lower in patients with diabetes mellitus (DM) compared with those without (1.7+/-0.74 vs 2.48+/-0.98, p<0.007), in patients with hypertension compared with those without (2+/-0.8 vs 2.6+/-0.9, p<0.02), and in obese patients compared with nonobese patients (1.6+/-0.5 vs 2+/-0.6, p<0.02). CFR was further impaired in the presence of DM with hypertension, DM with obesity, DM with a wide pulse pressure (>50 mm Hg), and obesity with a wide pulse pressure. In a multivariate model, DM, obesity, and wide pulse pressure were significantly associated with variation in CFR (p<0.0008). In conclusion, CFR was abnormal in patients with DM, hypertension, and obesity. CFR impairment is exaggerated as the number of risk factors increases. Despite a negative dobutamine stress echocardiographic result, aggressive risk factor assessment and control should be implemented in patients with coronary risk factors due to an underlying abnormal CFR.

The prognostic value of combined intracoronary pressure and blood flow velocity measurements after deferral of percutaneous coronary intervention

We evaluated deferral of PCI of intermediate coronary lesions (IL) using fractional (FFR) and coronary flow reserve (CFR) hyperemic stenosis resistance index (HSR) in patients with a negative or nondiagnostic and noninvasive stress tests. Outcome after deferral of PCI of IL with discordant results between FFR and CFR is unknown. PCI was deferred in 186 IL (mean diameter stenosis: 52%). Patients were divided according to the results of FFR and CFR in group A; FFR >or= 0.75 and CFR >or= 2.0 (n = 129), group B; FFR >or= 0.75 and CFR 2.0 (n = 28), group C; FFR 0.75 and CFR >or= 2.0 (n = 23) and group D; FFR 0.75 and CFR 2.0 (n = 6). Patients were followed for one year to document major adverse cardiac events (MACE). Nineteen MACEs (0 deaths, 4 myocardial infarctions, 1 CABG, and 14 PCIs) occurred during a follow up of 323 +/- 88 days. MACE rate was lowest (4.7%) when FFR, CFR, and HSR were normal. A higher MACE rate was observed when concordant abnormal (group D) or discordant results between FFR and CFR (group B and C) were compared to concordant normal values (group A, 33.3% vs. 19.7% vs. 5.4%, P = 0.008). Multivariate regression analysis showed a higher predictive power for HSR than for FFR and CFR. Abnormal FFR or abnormal CFR was documented in 31% of intermediate coronary lesions. Deferral of PCI in this group was associated with a high MACE rate, which underscores the rationale of combined pressure and flow measurements providing a stenosis resistance index that is better suited for clinical decision making in these lesions.