Prognostic Significance of Myocardial Fibrosis Quantification by Histopathology and Magnetic Resonance Imaging in Patients With Severe Aortic Valve Disease

OBJECTIVES: Does myocardial fibrosis (MF) in patients with severe aortic valve (AV) disease, assessed by histopathology or contrast-enhanced magnetic resonance imaging (ce-MRI), predict outcomes following surgical AV replacement?

METHODS: Fifty-four patients (mean age 46.8 years, 78% male) with symptomatic severe aortic regurgitation (n = 26) or aortic stenosis (n = 28) were prospectively evaluated. All patients underwent preoperative quantitative assessment of MF by ce-MRI and had myocardial tissue samples obtained during surgery for histopathologic evaluation. Patients were grouped based on degree of MF and were compared to assess for differences in left ventricular (LV) functional improvement and survival postoperatively.

RESULTS: ce-MRI assessment of MF correlated well with histopathology (r = 0.69, p < 0.0001), and the degree of MF was higher in the study group than in normal controls. LV functional changes were evaluated in 25 patients who underwent follow-up MRI; LV mass was decreased and LV ejection fraction (EF) improved (EF 54 ± 10% pre-op vs. 59 ± 14% post-op, p = 0.02). LVEF improvement was inversely related to the degree of pre-op MF. Overall, those who died had more MF, and this increased burden of MF was associated with lower postoperative survival. Finally, on multivariate analysis, the amount of MF, along with advanced age, independently predicted all-cause mortality.

CONCLUSIONS: In patients with severe AV disease, the amount of MF assessed by histopathology or ce-MRI is associated with LV function improvement and mortality. 

PMID: 20633819

Appropriate Use of Transthoracic Echocardiography

OBJECTIVES: The appropriateness criteria for echocardiography were published in 2007 and classified potential procedural indications as appropriate, uncertain, or inappropriate. The appropriate use rates for outpatient transthoracic echocardiography (TTE) by cardiologists have not been well defined. The objective of the present study was to prospectively determine the appropriate use rate of outpatient TTE in a large private practice group of >40 cardiologists (Cardiovascular Consultants, PA, Kansas City, Missouri).

METHODS: For each transthoracic echocardiographic study, we classified the stated reason for the examination into one of the 59 indications specified in the 2007 Appropriateness Criteria for Echocardiography publication. During the study period, 772 transthoracic echocardiographic studies were performed.

RESULTS: Adequate information was available to classify 716 (92.7%) of these studies. The transthoracic echocardiographic studies were appropriately ordered for 533 patients (74%). Symptoms of potential cardiac origin (eg, dyspnea) was the most common reason for TTE (n = 156, 21.8%). The most common inappropriate use was routine repeat evaluation of patients with heart failure and no change in clinical status (n = 74, 10.3%).

CONCLUSIONS: In conclusion, the appropriateness criteria for echocardiography were easily applied to real-world patients. Most patients in our series had undergone TTE for an appropriate indication.

PMID: 20494676

A Retrospective Comparison of Mortality in Critically Ill Hospitalized Patients Undergoing Echocardiography With and Without an Ultrasound Contrast Agent

OBJECTIVES: To compare acute mortality in critically ill hospitalized patients undergoing echocardiography with and without an ultrasound contrast agent (UCA).

BACKGROUND: Because of serious cardiopulmonary reactions reported immediately after administration of perflutren-containing UCAs, the FDA required a black box safety warning for this class of agents, including perflutren protein-type A microspheres injectable suspension.

METHODS: This study used the largest hospital service-level database in the U.S. All adult patients undergoing in-patient echocardiography between January 2003 and October 2005 were identified (n = 2,588,722, of which 22,499 received perflutren protein-type A microspheres injectable suspension). Of the 22,499 contrast echocardiography patients, 2,900 had diagnoses meeting criteria for critical illness (heart failure, acute myocardial infarction, arrhythmia, respiratory failure, pulmonary embolism, emphysema, and pulmonary hypertension). To control for the differences between the contrast and noncontrast patients, we used propensity score matching. Variables used in the construction of the propensity score included comorbidities, demographic factors, hospital-specific factors, level of care, and mechanical ventilation status. Patients receiving contrast echocardiography were matched to 4 control patients who received noncontrast echocardiography. Conditional logistic regression was used to estimate mortality effects.

RESULTS: There were 167 deaths in the study among critically ill patients, 38 of 2,900 from the contrast group and 129 of 11,600 from the control group. The contrast agent was not associated with an increase in same-day mortality (odds ratio: 1.18; 95% confidence interval: 0.82 to 1.71; p = 0.37). Before matching, contrast patients showed greater morbidity than noncontrast patients (Deyo-Charlson comorbidity score 2.45 vs. 2.25, p < 0.0001). After propensity score matching, these differences were significantly reduced, showing that both groups were well balanced.

CONCLUSIONS: There is no increase in mortality in critically ill patients undergoing echocardiography with the UCA compared with case-matched control patients.

PMID: 20541713

Independent Predictors of Survival in Primary Systemic (Al) Amyloidosis, Including Cardiac Biomarkers and Left Ventricular Strain Imaging: An Observational Cohort Study

OBJECTIVES: The prognostic value of Doppler myocardial imaging, including myocardial velocity imaging, strain, and strain rate imaging, in patients with primary (AL) amyloidosis is uncertain. The aim of this longitudinal study was to identify independent predictors of survival, comparing clinical data, hematologic and cardiac biomarkers, and standard echocardiographic and Doppler myocardial imaging measures in a cohort of patients with AL amyloidosis.

METHODS: A total of 249 consecutive patients with AL amyloidosis were prospectively enrolled. The primary end point was all-cause mortality, and during a median follow-up period of 18 months, 75 patients (30%) died. Clinical and electrocardiographic data, biomarkers (brain natriuretic peptide and cardiac troponin T) and standard echocardiographic and longitudinal systolic and diastolic Doppler myocardial imaging measurements for 16 left ventricular segments were tested as potential independent predictors of survival.

RESULTS: Age (hazard ratio [HR], 1.03; P = .03), New York Heart Association class III or IV (HR, 2.47; P = .01), the presence of pleural effusion (HR, 1.79; P = .08), brain natriuretic peptide level (HR, 1.29; P = .01), ejection time (HR, 0.99; P = .13), and peak longitudinal systolic strain of the basal anteroseptal segment (HR, 1.05; P = .02) were independent predictors in the final model.

CONCLUSIONS: Multivariate survival analysis identified independent predictors of clinical outcome in patients with AL amyloidosis: New York Heart Association class III or IV, presence of pleural effusion, brain natriuretic peptide level > 493 pg/mL, ejection time < 273 ms, and peak longitudinal systolic basal anteroseptal strain less negative than or equal to -7.5% defined a high-risk group of patients.

PMID: 20434879

Comprehensive Echocardiographic Assessment of Normal Mitral Medtronic Hancock II, Medtronic Mosaic, and Carpentier-Edwards Perimount Bioprostheses Early After Implantation

OBJECTIVES: Normal Doppler-derived hemodynamic data for mitral valve bioprostheses are limited.

METHODS: To establish parameters for identifying normal function for each of the 3 types of bioprostheses examined, we conducted a comprehensive, retrospective, two-dimensional, and Doppler echocardiographic assessment of 179 patients who underwent implantation of the Medtronic Hancock II or the Medtronic Mosaic (Medtronic, Inc, Minneapolis, MN) porcine mitral valve bioprosthesis or the Carpentier-Edwards Perimount (Edwards Lifesciences LLC, Irvine, CA) bovine pericardial mitral valve bioprosthesis.

RESULTS: All bioprostheses were normal by clinical examination, intraoperative transesophageal echocardiography, and postoperative transthoracic echocardiography. Regardless of valve type and body surface area, the pressure half-time was < 124 ms in all patients. Mean gradient < 9.5 mm Hg, mitral E velocity < 2.6 m/s, mitral valve prosthesis time-velocity integral < 69 cm, and ratio of the mitral valve prosthesis time-velocity integral to the left ventricular outflow tract time-velocity integral < 3.4 were recorded in nearly all patients.

CONCLUSIONS: These cutoff values (mean + 2 standard deviation) are specific, but not sensitive, for identifying mitral valve prosthesis dysfunction. Prostheses with hemodynamic values that are higher than these cutoff values are likely dysfunctional, but in select cases, mitral valve prosthesis dysfunction may be present even when hemodynamic values are lower than these thresholds.

PMID: 20497863

Comparison of Exercise Electrocardiography, Technetium-99m Sestamibi Single Photon Emission Computed Tomography, and Dobutamine and Dipyridamole Echocardiography for Detection of Coronary Artery disease in Hypertensive Women

OBJECTIVES: To assess the performance of currently used stress tests for the detection of coronary artery disease (CAD) in a series of female hypertensive patients.

METHODS: We performed exercise electrocardiography (ECG), technetium-99m sestamibi (MIBI) single photon emission computed tomography, dobutamine and dipyridamole echocardiography, and coronary angiography in 76 hypertensive women.

RESULTS: Of the 76 study patients, 31 (41%) had significant CAD. The sensitivity of exercise ECG (81%), MIBI scanning (90%), and dobutamine echocardiography (87%) was greater than that of dipyridamole echocardiography (61%). This finding resulted from the lower sensitivity of dipyridamole echocardiography in the detection of single-vessel CAD (47% vs 76%, 88%, and 82% for the other 3 methods). In contrast, the sensitivity of the 4 tests was similar in the detection of multivessel CAD. The specificity of exercise ECG (56%) and MIBI scanning (53%) was less than that of dobutamine (82%, both p <0.01) and dipyridamole (91%, both p <0.001) echocardiography. This finding related to the lower specificity of exercise ECG in patients with either left ventricular hypertrophy or ST-T abnormalities at rest compared to the specificity in patients without these disorders (33% vs 89%, p <0.01). A lower MIBI scan specificity was found only in patients with left ventricular hypertrophy (31% vs 66%, p <0.05). The overall accuracy of dobutamine echocardiography reached 84% compared to exercise ECG (66%, p <0.01), MIBI scan (68%, p <0.05), and dipyridamole echocardiography (79%, p <0.05).

CONLCUSIONS: In conclusion, dobutamine echocardiography yielded satisfactory diagnostic accuracy for identifying CAD in hypertensive women. Although dipyridamole echocardiography had the greatest specificity, it might be limited in detecting mild CAD. Both exercise ECG and MIBI scanning had fare sensitivity; however, our findings limit the usefulness of these 2 tests in unselected patients.

PMID: 20403475

Transthoracic and Transesophageal Echocardiography for the Indication of Suspected Infective Endocarditis: Vegetations, Blood Cultures and Imaging

OBJECTIVES: The aim of this study was to investigate the ability of transthoracic echocardiography (TTE) to detect vegetations and the relationship between blood cultures and transesophageal echocardiography (TEE).

METHODS: Five hundred eleven TTE and TEE pairs performed to evaluate endocarditis were retrospectively analyzed. Vegetation on TTE, prosthetic valve, change in regurgitation, and blood cultures were correlated with vegetation on TEE.

RESULTS: TTE detected 45% of vegetations seen on TEE. There was no difference for prosthetic valves. Prosthetic valves (odds ratio, 1.7; P = .03) and increased regurgitation (odds ratio, 1.7; P = .01) were associated with vegetations on TEE; staphylococcal bacteremia and fungemia were not. Negative blood cultures were associated with negative results on TEE (P < .0001), but 27% of patients with prosthetic valves had culture-negative endocarditis or nonbacterial thrombotic endocarditis, and 6% had abscesses missed by TTE.

CONCLUSIONS: This study demonstrates a limited capacity of TTE to detect vegetations. TEE may be an appropriate initial study to evaluate prosthetic valves. TEE for culture-negative endocarditis deserves further study.

PMID: 20138467

Prognostic Implications of Left Ventricular Filling Pressure With Exercise

OBJECTIVES:  The estimation of left ventricular (LV) filling pressure from the ratio of transmitral and annular velocities (E/e’) after exercise echocardiography may identify diastolic dysfunction in patients who complain of exertional dyspnea. This study sought to determine the relative contributions of exercise E/e’ and ischemia to outcomes in patients referred for exercise echocardiography.

METHODS:  Rest and exercise E/e’ were obtained in 522 patients referred for exercise echocardiography, who were followed for cardiovascular death and hospitalization over a median of 13.2 months. Exercise E/e’ >2 SD from normal was used to denote raised LV filling pressure with stress (n=75), and ischemia (n=250) was identified by inducible wall motion abnormalities.

RESULTS: There were 65 cardiovascular hospitalizations during the follow-up period. Survival analysis showed patients without ischemia and with normal exercise E/e’ to have a better prognosis than those with ischemia, with or without raised exercise E/e’ (P=0.003) and the outcomes of patients with isolated raised exercise E/e’ and isolated ischemia to be similar. Exercise E/e’ was most valuable in patients with normal resting E/e’; those with elevation with exercise had a worse outcome than those with normal exercise E/e’ (P=0.014). Exercise capacity (hazard ratio, 0.893; P=0.008), exercise wall motion score index (hazard ratio, 1.507; P<0.001), and exercise E/e’ >14.5 (hazard ratio, 2.988; P=0.002) were independent predictors of outcome. The addition of exercise E/e’ to exercise capacity and wall motion score index resulted in an increment in model power to predict adverse outcome (P=0.006).

CONCLUSIONS:  Exercise E/e’ is associated with cardiovascular hospitalization, independent of and incremental to inducible ischemia.

PMID: 20233862

Do Additional Echocardiographic Variables Increase the Accuracy of E/e’ for Predicting Left Ventricular Filling Pressure in Normal Ejection Fraction? An Echocardiographic and Invasive Hemodynamic Study

OBJECTIVIES: There are few data on adding left atrial volume index (LAVi) or pulmonary artery systolic pressure (PAP) to the ratio of early mitral inflow to mitral annular velocity (E/e’) for the estimation of left ventricular (LV) filling pressure in patients with preserved LV ejection fractions (LVEFs) (>50%).

METHODS: Patients underwent echocardiography within 20 minutes of cardiac catheterization. Echocardiographic variables were compared with invasively measured LV preatrial contraction pressure (pre-A).

RESULTS: Of the 122 patients studied (mean age, 55 +/- 9 years; mean LVEF, 61 +/- 6%), 67 (55%) were women, 108 (88%) had hypertension, and 79 (65%) had significant coronary artery disease at catheterization. E/e’ was significantly correlated with pre-A (R = 0.63, P < .0001) compared with LAVi (R = 0.49, P < .001) and PAP (R = 0.48, P < .001). E/e’ > 13 had sensitivity of 70% and specificity of 93% (area under the curve [AUC], 0.82; P < .0001), LAVi > 31 mL/m2 had sensitivity of 78% and specificity of 76% (AUC, 0.80, P < .001), and PAP > 28 mm Hg had sensitivity of 80% and specificity of 64% for pre-A > 15 mm Hg (AUC, 0.77, P < .001). Adding LAVi >31 mL/m2 for E/e’ = 8 to 13 significantly increased the accuracy of E/e’ > 13 alone (sensitivity, 87%; specificity, 88%; AUC, 0.89; P = .01 for comparison). However, adding PAP > 28 mm Hg for E/e’ = 8 to 13 did not significantly increase the accuracy of E/e’ > 13 alone (AUC, 0.82; sensitivity, 82%; specificity, 72%; P = NS for comparison).

CONCLUSIONS: In patients with preserved LVEFs, adding LAVi > 31 mL/m2 to E/e’ (when E/e’ was in the gray zone, but not when E/e’ was >13) significantly increased the accuracy of E/e’ alone for the estimation of LV filling pressure. These data support the notion of using several, rather than any single, Doppler echocardiographic parameter for the accurate assessment of LV diastolic function.

PMID: 20152696

Patent Foramen Ovale: Echocardiographic Detection and Clinical Relevance in Stroke

This article reviews the main clinical aspects of patent foramen ovale (PFO), such as its prevalence in the population, the diagnostic techniques to detect its presence, its role as a risk factor for ischemic stroke of otherwise unexplained origin, and its controversial association with migraine. Some cofactors possibly involved in the association between PFO and stroke are discussed, along with the various therapeutic options to prevent recurrent cerebral ischemic events in stroke patients with a PFO.

PMID: 20152695

Reference Values for Right Ventricular Volumes and Ejection Fraction With Real-Time Three-Dimensional Echocardiography: Evaluation in a Large Series of Normal Subjects

OBJECTIVES: The quantification of right ventricular (RV) size and function is of diagnostic and prognostic importance. Recently, new software for the analysis of RV geometry using three-dimensional (3D) echocardiographic images has been validated. The aim of this study was to provide normal reference values for RV volumes and function using this technique.

METHODS: A total of 245 subjects, including 15 to 20 subjects for each gender and age decile, were studied. Dedicated 3D acquisitions of the right ventricle were obtained in all subjects.

RESULTS: The mean RV end-diastolic and end-systolic volumes were 49 ± 10 and 16 ± 6 mL/m2 respectively, and the mean RV ejection fraction was 67 ± 8%. Significant correlations were observed between RV parameters and body surface area. Normalized RV volumes were significantly correlated with age and gender. RV ejection fractions were lower in men, but differences across age deciles were not evident.

CONCLUSIONS: The current study provides normal reference values for RV volumes and function that may be useful for the identification of clinical abnormalities.

PMID:

Viability Assessment With Global Left Ventricular Longitudinal Strain Predicts Recovery of Left Ventricular Function After Acute Myocardial Infarction

OBJECTIVES: The extent of viable myocardial tissue is recognized as a major determinant of recovery of left ventricular (LV) function after myocardial infarction. In the current study, the role of global LV strain assessed with novel automated function imaging (AFI) to predict functional recovery after acute infarction was evaluated.

METHODS: A total of 147 patients (mean age, 61±11 years) admitted for acute myocardial infarction were included. All patients underwent 2D echocardiography within 48 hours of admission.

RESULTS: Significant relations were observed between baseline AFI global LV strain and peak level of troponin T (r=0.64), peak level of creatine phosphokinase (r=0.62), wall motion score index (r=0.52), and viability index assessed with single-photon emission computed tomography (r=0.79). At 1-year follow-up, LV ejection fraction was reassessed. Patients with absolute improvement in LV ejection fraction >5% at 1-year follow-up (n=70; 48%) had a higher (more negative) baseline AFI global LV strain (P<0.0001). Baseline AFI global LV strain was a predictor for change in LV ejection fraction at 1-year follow-up. A cutoff value for baseline AFI global LV strain of –13.7% yielded a sensitivity of 86% and a specificity of 74% to predict LV functional recovery at 1-year follow-up.

CONCLUSIONS: AFI global LV strain early after acute myocardial infarction reflects myocardial viability and predicts recovery of LV function at 1-year follow-up.

PMID: 19820202

Left Ventricular Diastolic Function in Type 2 Diabetes Mellitus: Prevalence and Association With Myocardial and Vascular Disease

OBJECTIVES: Although type 2 diabetes mellitus is a risk factor for developing congestive heart failure, the mechanism leading to heart failure is unclear. We examined the prevalence of left ventricular (LV) systolic and diastolic dysfunction in patients with type 2 diabetes mellitus in relation to vascular function and myocardial perfusion.

METHODS: A prospective observational study of 305 patients with type 2 diabetes mellitus (diabetes duration, 4.5±5.3 years) referred consecutively to a diabetes clinic were screened for LV systolic and diastolic function by echocardiography. Vascular function was estimated using noninvasive estimation of pulse pressure, carotid arterial compliance, total arterial compliance, and valvulo-arterial impedance.

RESULTS: The prevalences of LV diastolic dysfunction and left atrial (LA) volume index >32 mL/m² were 40% and 32%, respectively. The prevalence of myocardial ischemia on myocardial perfusion scintigraphy was more frequent in patients with grade 2 diastolic dysfunction and LA volume index >32 mL/m² compared with those having normal or grade 1 diastolic dysfunction (P=0.002) or LA volume index < 32 mL/m² (P<0.001), respectively. Predictors of grade 2 diastolic dysfunction and LA dilation were summed stress score on myocardial perfusion scintigraphy, total arterial compliance, and valvulo-arterial impedance, whereas pulse pressure and carotid arterial compliance were not, after adjusting for age, sex, and diabetes duration. On multivariable modeling, summed stress score (P<0.001) and valvulo-arterial impedance (P=0.027) remained predictors of grade 2 diastolic dysfunction, and only summed stress score (P<0.001) was a predictor of LA dilation.

CONCLUSIONS: Abnormal LV filling is closely associated with abnormal myocardial perfusion on myocardial perfusion scintigraphy, whereas the association of LV filling with vascular function is less prominent.

PMID: 19846730

Echocardiographic Epicardial Fat: A Review of Research and Clinical Applications

Epicardial fat plays a role in cardiovascular diseases. Because of its anatomic and functional proximity to the myocardium and its intense metabolic activity, some interactions between the heart and its visceral fat depot have been suggested. Epicardial fat can be visualized and measured using standard two-dimensional echocardiography. Standard parasternal long-axis and short-axis views permit the most accurate measurement of epicardial fat thickness overlying the right ventricle. Epicardial fat thickness is generally identified as the echo-free space between the outer wall of the myocardium and the visceral layer of pericardium and is measured perpendicularly on the free wall of the right ventricle at end-systole. Echocardiographic epicardial fat thickness ranges from a minimum of 1 mm to a maximum of almost 23 mm. Echocardiographic epicardial fat thickness clearly reflects visceral adiposity rather than general obesity. It correlates with metabolic syndrome, insulin resistance, coronary artery disease, and subclinical atherosclerosis, and therefore it might serve as a simple tool for cardiometabolic risk prediction. Substantial changes in echocardiographic epicardial fat thickness during weight-loss strategies may also suggest its use as a marker of therapeutic effect. Echocardiographic epicardial fat measurement in both clinical and research scenarios has several advantages, including its low cost, easy accessibility, rapid applicability, and good reproducibility. However, more evidence is necessary to evaluate whether echocardiographic epicardial fat thickness may become a routine way of assessing cardiovascular risk in a clinical setting.

PMID: 19944955

Comparison of Multidetector-Row Computed Tomography to Echocardiography and Fluoroscopy for Evaluation of Patients with Mechanical Prosthetic Valve Obstruction

OBJECTIVES: For evaluation of prosthetic heart valve obstruction echocardiography and fluoroscopy provide primarily functional information, but may not unequivocally establish the cause of dysfunction. Our objective was to evaluate whether multidetector-row computed tomographic (MDCT) imaging could detect the morphologic substrate for such functional abnormalities.

METHODS: Thirteen patients with 15 prosthetic valves, in whom prosthetic valve obstruction was suspected from echocardiography or fluoroscopy, but no sufficient cause could be found, underwent electrocardiographically gated multidetector-row computed tomography. MDCT data were retrospectively reconstructed at every 10% of the electrocardiographic interval and analyzed using multiplanar reformatting in anatomically adapted planes. MDCT images were evaluated for morphologic prosthetic and periprosthetic abnormalities.

RESULTS: Results could be compared to intraoperative findings or autopsy in 7 patients. Multidetector-row computed tomography disclosed a morphologic substrate for obstruction in 8 of 13 patients. MDCT findings compatible with obstruction were confirmed at surgery or autopsy in 6 patients. In a seventh patient, incomplete leaflet closure found with multidetector-row computed tomography was confirmed at surgery. The most commonly identified causes for obstruction were subprosthetic tissue (6 patients) and abnormal anatomic orientation (3 patients). Despite an indication for surgery, 2 patients were not operated on due to recurrent bacteremias and prohibitive co-morbidity. Multidetector-row computed tomography detected leaflet motion restriction in 7 patients compared to 4 by fluoroscopy. Confirmation of leaflet restriction was available in 5 patients. Multidetector-row computed tomography missed a periprosthetic leak.

CONCLUSIONS: In conclusion, this initial experience demonstrates that multidetector-row computed tomography can identify causes of prosthetic valve obstruction that constitute indications for surgery, but are missed at echocardiography or fluoroscopy.

PMID: 19801036