Age alone is not a risk factor for left atrial thrombus in atrial fibrillation.

OBJECTIVE: Advanced age is an indication for anticoagulation in patients with atrial fibrillation though it is not clear that elderly patients have a higher prevalence of left atrial thrombus. The purpose of this study was to clarify whether advanced age represents a risk for left atrial thrombus formation irrespective of other clinical variables. DESIGN: Observational study in patients with atrial fibrillation undergoing a transoesophageal echo scan for various clinical indications. SETTING: University-affiliated cardiology service in a general hospital. PATIENTS: Results are reported in 381 patients, 257 aged less than 75 years (Gr. A) and 124 aged 75 years or more (Gr. B). RESULTS: Thrombi were detected by TOE in 30 patients (7.9%), 21 from group A and nine from group B (8.1% vs 7.2%, p = NS). No thrombi were detected in patients with lone atrial fibrillation. Among patients with either valvular or nonvalvular atrial fibrillation, left atrial thrombus presence was not related to age or anticoagulation status. CONCLUSIONS: In patients with atrial fibrillation, age itself does not predict the presence of left atrial thrombus and the only identifiable risk factor seems to be the existing cardiac pathology.

The peripheral vascular response to exercise is impaired in patients with risk factors for coronary artery disease.

BACKGROUND: Abnormal coronary and brachial artery responses have been described in individuals with risk factors for coronary artery disease (CAD). Peripheral arterial tonometry (PAT), a newly developed digital plethysmographic technique was used to assess peripheral vascular response to exercise in healthy controls and individuals with risk factors. METHODS AND RESULTS: Continuous finger PAT during Bruce protocol exercise test was performed in 30 subjects with risk factors for CAD and 30 healthy individuals. Compared with baseline, the PAT wave amplitude at peak exercise decreased in the subjects but increased in the controls: 83 +/- 28% vs. 114 +/- 40% respectively, p < 0.01. CONCLUSIONS: A different pattern of systemic vascular response to exercise was found in individuals with risk factors for atherosclerosis. Since the vascular behavior in these patients is probably related to endothelial dysfunction, it may be that peripheral arterial tonometry can be used as a simple, readily available technique to assess endothelial function.

Relation of coronary artery disease to atherosclerotic disease in the aorta, carotid, and femoral arteries evaluated by ultrasound.

This prospective study was conducted to correlate the presence of angiographically significant coronary artery disease (CAD) and atherosclerotic disease in the aorta, carotid, and femoral arteries as measured by ultrasound. One hundred two consecutive patients admitted for coronary angiography for suspected CAD participated in the study. All patients underwent transesophageal echocardiography for the evaluation of thoracic aortic atherosclerosis and B-mode ultrasound for evaluation of carotid and femoral atherosclerosis. Intimal-medial thickness > 1 mm in the thoracic aorta or peripheral vessels was considered as evidence of atherosclerosis. Patients with CAD (n = 64) had a significantly higher incidence of atherosclerotic plaques in the thoracic aorta, carotid, and femoral arteries than subjects with normal coronary arteries: 91%, 72%, 77% vs 31%, 47% and 42%, respectively. Extracoronary plaque was a stronger predictor of CAD than conventional risk factors. Evidence of plaque in patients younger than median age (64 years) had a higher specificity than in patients above median age (77% vs 40%, respectively, p <0.0001). Plaque score of the extracardiac vessels was significantly higher in patients with multivessel CAD than in patients with 1-vessel CAD disease and in subjects with normal coronary arteries (p <0.001). Thus, atherosclerotic plaques in the aortic and femoral arteries and, to a lesser extent, in the carotid arteries are strong predictors of CAD.

Influence of preexistent donor coronary artery disease on the progression of transplant vasculopathy. An intravascular ultrasound study.

BACKGROUND: Transplant vasculopathy (TxCAD) limits longterm survival of allograft recipients. The possibility that preexistent donor coronary disease (PEDD) might accelerate this process is of concern. The serial progression of sites with and without PEDD as assessed by intravascular ultrasonic imaging is explored in this study. METHODS AND RESULTS: Thirty patients with baseline intravascular imaging within 3 weeks of cardiac transplantation who had at least one annual follow-up study were included in this study. Vessel luminal area (LA), total area (TA), intimal index (II = TA - LA/TA), mean intimal thickness (MIT), and Stanford classification were expressed for each image site and for each patient at each study. Progression of sites and of patients with and without PEDD on the baseline study was compared. Patients with PEDD (n = 9) still had significantly more intimal disease than those without PEDD (n = 21) at the first follow-up study (MIT = 0.35 +/- 0.13 versus 0.13 +/- 0.11 mm; II = 0.29 +/- 0.11 versus 0.11 +/- 0.1; class = 3.7 +/- 0.5 versus 2.2 +/- 0.94; P < .001 for all comparisons). However, the increase in intimal thickness during the 1- year interval was not significantly different between the two groups. In 4 patients in whom both types of sites were present, no difference in progression was found. Data were similar for patients and sites studied over > 1 year. CONCLUSIONS: PEDD does not accelerate the progression of TxCAD within the first few years after cardiac transplantation. The pathophysiology of TxCAD is most likely immune mediated and does not seem to be accelerated by native coronary artery disease.

Incidence and severity of transplant coronary artery disease early and up to 15 years after transplantation as detected by intravascular ultrasound.

OBJECTIVES: The purpose of this study was to quantify the severity of transplant coronary artery disease and to assess lesion characteristics early and up to 15 years after heart transplantation by using intracoronary ultrasound. BACKGROUND: Intravascular ultrasound has the ability to measure the components of the arterial wall and has been shown to be a sensitive method for detection of transplant coronary artery disease. METHODS: A total of 304 intracoronary ultrasound studies were performed in 174 heart transplant recipients at baseline and up to 15 (mean 3.3 +/- 0.2) years after transplantation. Mean intimal thickness and an intimal index were calculated, and lesion characteristics (eccentricity, calcification) were assessed for all coronary sites imaged (mean 3.0 +/- 0.1 sites/study). The Stanford classification was used to grade lesion severity. RESULTS: Compared with findings in patients studied at baseline (< 2 months after transplantation, n = 50), mean intimal thickness (0.09 +/- 0.02 vs. 0.16 +/- 0.02 mm, p < 0.01), intimal index (0.07 +/- 0.01 vs. 0.14 +/- 0.02, p < 0.01) and mean severity class (1.5 +/- 0.2 vs. 2.3 +/- 0.2, p < 0.01) were significantly higher at year 1 (n = 52) after transplantation. Thereafter, all three variables further increased over time and reached highest values between years 5 and 15. Calcification of lesions was detected in 2% to 12% of studies up to 5 years after transplantation, with a significant increase to 24% at years 6 to 10 (p < 0.05). CONCLUSIONS: Severity of transplant coronary artery disease appeared to progress with time after transplantation in this cross-sectional study. This characteristic was most prominent during the 1st 2 years after transplantation, whereas calcification of plaques occurred to a significant extent only later in the process. These data may serve as a reference for comparison of intravascular ultrasound findings in other studies of patients with transplant coronary artery disease.

Distribution and morphologic features of coronary artery disease in cardiac allografts: an intracoronary ultrasound study.

The longitudinal distribution and circumferential pattern of coronary intimal proliferation were studied with intravascular ultrasonography in 135 patients after heart transplantation. Eighty-seven (64%) of 135 patients had significant intimal thickening, with most lesions (63%) concentric and free of fibrosis or calcification. Both diffuse and nonuniform longitudinal patterns of intimal thickening were found.

On-line estimation of cardiac output with a new automated border detection system using transesophageal echocardiography: a preliminary comparison with thermodilution.

Continuous estimation of cardiac output would be extremely useful for hemodynamic monitoring of patients in the operating room and intensive care settings. A recently developed echocardiographic imaging system provides real-time automated border detection (ABD) with the ability to measure cyclic changes in cavity area, and thus calculate changes in intracavitary volumes. Eight patients undergoing cardiac surgery were studied with intraoperative transesophageal (TEE), and cardiac outputs obtained with this new imaging system were compared with thermodilution (TD). Triplicate measurements were obtained simultaneously at five intraoperative times, three before and two after cardiopulmonary bypass. The 91 of 120 measurements with adequate TEE and TD data were analyzed. The average difference between the two techniques (bias) was -0.2 +/- 1.3 L/min. The limits of agreement (bias +/- 2 SD) were -2.8 L/min to 2.4 L/min. The average of the absolute value of the difference between measurements made with the two techniques was 0.9 +/- 0.8 L/min. Linear regression yielded the equation: ABD = 0.64TD + 1.57 L/min (r = 0.71). The average difference between the two techniques (bias) for detecting changes in cardiac output between sequential intraoperative times was 0.1 +/- 1.1 L/min. With further development, this new method shows promise for measurement of cardiac output in selected patient care settings.

Feasibility of serial intracoronary ultrasound imaging for assessment of progression of intimal proliferation in cardiac transplant recipients.

BACKGROUND: Serial quantitative coronary angiography is used to assess progression of coronary disease; however, pathology studies have demonstrated angiographic insensitivity for determining atheroma. Intracoronary ultrasound (ICUS) can define and measure the components of the arterial wall and offers the potential for precise quantitative assessment of disease progression on serial examinations. The present study was done to test the feasibility of serially assessing intimal proliferation at the same coronary site with ICUS imaging in cardiac transplant recipients. METHODS AND RESULTS: ICUS imaging was done with a 30-MHz, 5F or 4.3F ultrasound imaging catheter at the time of angiography in 70 cardiac allografts (3.8 sites per patient) initially and 1 year later. Mean intimal thickness (IT), luminal area (LA), and total area (TA) of lumen plus intima and an index of intimal thickness (II = TA - LA/TA) were measured at each site. Additionally, vessels were graded using a scale incorporating criteria of intimal thickness and circumferential involvement. Side-by-side comparisons of paired angiograms were performed both to verify the similarity of ICUS imaging site and to detect new angiographic abnormalities. At least one site could be assessed serially by ICUS in 100% of patients, but only 189 of the original 263 coronary sites (72%) (2.7 sites per patient) could be matched satisfactorily on the second study. Thirty-nine patients (56%) had mild IT and 31 patients (44%) had moderate or severe IT on the initial study. Both groups showed the same IT progression the following year (delta = 0.05 +/- 0.13 versus 0.07 +/- 0.15 mm; P = NS). Twenty-seven of the 70 patients (39%) showed progression by ICUS. The 23 patients with ICUS progression and angiographically normal vessels had the same progression in intimal thickening as the 4 patients with ICUS progression but showing angiographic disease (delta = 0.17 +/- 0.13 versus 0.22 +/- 0.10 mm; P = NS). CONCLUSIONS: Replication of the intracoronary imaging site by judgment of two observers at an initial study and at a second study 1 year later was possible in at least one vessel site in 100% of the 70 patients and in 72% (189 of 263) of the original imaging sites (2.7 sites per patient). Serial ICUS demonstrates progression of intimal thickening at specific sites in only some cardiac transplant patients. Progression of intimal proliferation can occur in individuals in the presence or absence of initially increased intimal thickening or of angiographic disease at the time of the initial studies. Angiography is insensitive for recognizing early intimal thickening of the coronary vessels.

Transesophageal echocardiography in the intensive care unit: impact on diagnosis and decision-making.

Transesophageal echocardiography (TEE) is widely used in the management of patients in intensive care units. The present study assesses the specific value of this technique in various categories of these patients. We reviewed 113 studies performed in 100 such patients for: suspected aortic dissection (25), suspected endocarditis (33), source of emboli assessment (19), hemodynamic instability (15), and miscellaneous (21). TEE provided diagnostic information in all patients with aortic dissection, in 53% of the cases with hemodynamic instability, in 50% of the cases with septic states with high likelihood of endocarditis, and in 29% of the cases where the question was the source of emboli. When the clinical probability for endocarditis was low, all transesophageal echocardiograms performed in septic patients were negative. The information provided by TEE was considered crucial in one-third of the positive cases; in about one-half of these special cases, the results were instrumental for further surgical management. There were no significant side effects related to the procedure. TEE is easily performed in the intensive care unit setting and yields useful information in almost half of the cases. Special benefit is expected in suspected aortic disease, hemodynamic instability, suspected endocarditis, and embolic events. The overall yield as screening procedure in febrile patients is low.

Effect of L-arginine on coronary endothelial function in cardiac transplant recipients. Relation to vessel wall morphology.

BACKGROUND: Coronary endothelial vasodilator dysfunction is a common finding in cardiac transplant recipients and may represent an early marker for the development of intimal thickening and graft atherosclerosis. The present study tested the hypothesis that endothelial dysfunction precedes intimal thickening and that administration of L-arginine, the precursor of endothelium-derived relaxing factor, improves endothelial vasodilator function of coronary conduit and resistance vessels if given at an early stage of graft atherosclerosis. METHODS AND RESULTS: Acetylcholine (10(-6), 10(-5), 10(-4) mol/L) was infused into the left anterior descending or circumflex artery and repeated after intravenous infusion of L-arginine (10 mg.kg-1.min-1 over 20 minutes) in 18 cardiac transplant recipients. Epicardial responses were evaluated by quantitative angiography, and the microcirculation was studied by determination of coronary blood flow with a Doppler flow velocity wire. Intimal thickening was assessed by intravascular ultrasound (n = 14). In epicardial coronary arteries, acetylcholine tended to elicit vasoconstriction. Epicardial coronary vasoconstriction elicited by acetylcholine was attenuated by infusion of L-arginine (10(-4) mol/L, -6.8% versus -2.8%; P < .01); this beneficial effect was observed predominantly in patients with normal intravascular ultrasound characteristics. In coronary resistance vessels, acetylcholine induced vasodilation, reflected by increases in coronary blood flow. The acetylcholine-induced increase in blood flow was significantly enhanced with L-arginine (at a dose of 10(-4) mol/L, + 121% versus 176%; before versus after L-arginine, P < .002). CONCLUSIONS: The coronary vasculature of cardiac transplant recipients exhibits a generalized endothelial dysfunction of conduit and resistance vessels. L-Arginine improves endothelial dysfunction of both coronary microvasculature and epicardial coronary arteries. The reversibility of epicardial endothelial dysfunction by L-arginine is more likely in vessels with normal wall morphology.

Balloon angioplasty results in increased segmental coronary distensibility: a likely mechanism of percutaneous transluminal coronary angioplasty.

OBJECTIVES: The purpose of this study was to evaluate the hypothesis that the increase in lumen area induced by percutaneous transluminal coronary angioplasty is secondary to a change in lesion (segmental) distensibility. BACKGROUND: Despite the widespread use of coronary angioplasty, the precise mechanism (or mechanisms) of lumen area improvement remains poorly understood. METHODS: Quantitative coronary angiography was used to measure the minimal (contrast agent filled) balloon diameters at 1 to 5 atm, inclusive, during the first and final balloon inflations in 24 lesions successfully treated with coronary angioplasty. To rule out possible confounding effects due to changes in balloon material distensibility during repeated inflations, five control balloons were studied ex vivo. In parallel, intravascular ultrasound imaging was utilized to compare the segmental distensibility (change in lumen area during the cardiac cycle) of eight disease-free and seven mildly diseased coronary segments and seven segments after successful balloon angioplasty. RESULTS: Minimal balloon diameters increased significantly between the first and final inflations (46%, 33%, 26%, 14% and 10% at 1, 2, 3, 4 and 5 atm, respectively, all p < 0.0001), demonstrating an increase in arterial distensibility after successful coronary angioplasty. No significant changes in balloon diameters were observed during sequential initial inflations at 1 and 2 atm (n = 5). Minimal increases in balloon diameters were observed during repeated balloon inflations in the ex vivo studies (4.9 +/- 1% [mean +/- SEM]). A distensibility index, derived from the intravascular ultrasound data, was not different between the balloon-dilated and the normal segments but was significantly lower in mildly diseased sites (14.7 +/- 2.2 vs. 12.9 +/- 1.2 vs. 6.9 +/- 1.9, respectively, p < 0.05) despite a smaller plaque area (7.3 +/- 1 vs. 11.3 +/- 1 mm2, proximal/nondilated vs. dilated segments, respectively, p < 0.05). CONCLUSIONS: Coronary distensibility is significantly impaired in atherosclerotically diseased coronary segments and increases significantly after balloon angioplasty. This increase in segmental coronary compliance after coronary angioplasty may create a larger lumen area by allowing the vessel to distend in response to normal intraarterial pressure.

Filling patterns in left ventricular hypertrophy: a combined acoustic quantification and Doppler study.

OBJECTIVES: The purpose of this study was to evaluate the potential of acoustic quantification compared with Doppler echocardiography for assessment of left ventricular diastolic dysfunction. BACKGROUND: Diastolic dysfunction usually accompanies left ventricular hypertrophy. Although Doppler echocardiography is widely used, it has known limitations in the diagnosis of diastolic abnormalities. The ventricular area-change waveform obtained with acoustic quantification technology may provide an alternative to assess diastolic dysfunction. METHODS: Potential acoustic quantification variables (peak rate of area change and mean slope of area change rate during rapid filling, amount of relative area change during rapid filling and atrial contraction) were obtained and compared with widely used Doppler indexes of ventricular filling (isovolumetric relaxation time, pressure half-time, peak early diastolic velocity/peak late diastolic velocity ratio, rapid filling, atrial contribution to filling) in 16 healthy volunteers and 30 patients with left ventricular hypertrophy. RESULTS: Criteria for abnormal relaxation were present in 68% of patients by acoustic quantification and in 64% of patients by Doppler echocardiography. However, abnormal relaxation was identified in 80% of patients by one or both methods. Acoustic quantification indicated abnormal relaxation in the presence of completely normalized Doppler patterns and in patients with mitral regurgitation or abnormal rhythm with unreliable Doppler patterns. CONCLUSIONS: Acoustic quantification potentially presents a new way to assess diastolic dysfunction. This technique may be regarded as complementary to Doppler echocardiography. The combined use of the methods may improve the diagnosis of left ventricular relaxation abnormalities.

Comparison of acoustic quantification and Doppler echocardiography in assessment of left ventricular diastolic variables.

OBJECTIVE: To assess the haemodynamic correlations of the waveforms of left ventricular area change obtained by automated boundary detection with newly developed acoustic quantification technology. DESIGN: The timing of events in the cardiac cycle was identified on the wave-form automated boundary detection and was correlated with the corresponding timing derived from pulsed wave Doppler flow velocity traces of the mitral valve and left ventricular outflow tract. The amounts of area change during the rapid filling phase and during atrial contraction were correlated with the time-velocity integrals of early and late diastolic ventricular filling obtained from Doppler tracings of the mitral inflow. SETTING: A university medical school echocardiography laboratory. SUBJECTS: 16 healthy volunteers and 19 patients referred for echocardiographic studies. RESULTS: A significant correlation was found between the methods for measurement of the time from the R wave to mitral valve opening (r = 0.72, p < 0.01), isovolumic relaxation time (r = 0.62, p < 0.01), and ejection time (r = 0.54, p < 0.01). The change of total area that occurred during rapid filling and atrial filling phases measured from the acoustic waveform correlated with the time-velocity integrals of the early and late diastolic mitral valve inflow velocity derived from Doppler echocardiography (r = 0.60 and r = 0.80, respectively). CONCLUSION: The waveform of left ventricular area obtained by the automated boundary detection technique identifies the phases of the cardiac cycle and correlates with Doppler values of left ventricular diastolic function. Therefore, this new method of automated boundary detection has potential uses in the assessment of left ventricular diastolic function.

Immediate and one-year safety of intracoronary ultrasonic imaging. Evaluation with serial quantitative angiography.

BACKGROUND: Intracoronary ultrasound (ICUS) has the ability to quantitatively evaluate vessel wall morphology and is well suited for serial studies of coronary artery disease regression and progression. However, the potential risk for catheter-induced endothelial damage and accelerated atherosclerosis in instrumented vessels is a concern. The acute effects as well as the 1-year safety of ICUS regarding its impact on the atherosclerotic process were assessed. METHODS AND RESULTS: The acute studies include 240 intracoronary studies performed in 170 cardiac transplant recipients. Patients were systematically heparinized. Only vessels > or = 2 mm in diameter were visualized. Coronary arteries of 38 patients were measured by quantitative coronary angiography in matched angiograms at an interval of 1 year after the initial ICUS examination was performed to assess long-term effects. The angiographic measurements in the previously instrumented and noninstrumented vessels were compared. Forty-nine vessels that had been imaged (IM) in these 38 patients with a 5F ICUS catheter were compared with 61 vessels not previously imaged (NIM) in the same patients. Absolute and percentage change in angiographically measured mean vessel diameters in the ICUS imaged and nonimaged segments were compared. Despite pretreatment with nitroglycerin, 20 patients (8.3%) had angiographically evident coronary spasm. In all cases, this was reversed by giving nitroglycerin. One year after the original imaging study, no difference was noted between imaged and nonimaged vessels in change in absolute vessel diameter (IM, -0.11 +/- 0.28 mm vs NIM, -0.07 +/- 0.22 mm; P = .49) or in percentage change in diameter (IM, -5 +/- 11% vs NIM, -3 +/- 7%; P = .32). CONCLUSIONS: Intracoronary ultrasound in cardiac transplant recipients was associated with no clinical morbidity and a low incidence of vessel spasm in large and medium-size coronary arteries. It does not accelerate progression of angiographically quantifiable coronary artery disease. This study suggests that ICUS can be safely used even in coronary arteries not undergoing interventions.

Biplane transesophageal echocardiography in the diagnosis of patent foramen ovale.

Patent foramen ovale is associated with unexplained systemic embolic events or persistent hypoxemia. The diagnosis of a patient foramen ovale is based on the existence of an interatrial right-to-left shunt. Biplane transesophageal echocardiography with its increased ability to provide accurate anatomic detail may allow the visualization of the actual opening of the patent foramen ovale. In 19 patients with transesophageal positive contrast studies, we assessed the value of the vertical versus the horizontal plane in the diagnosis of a patent foramen ovale. The patent foramen ovale opening could be seen and sized in the vertical plane in 10 studies (53%). In none of these 10 cases was the opening seen also in the horizontal plane. We conclude that in a significant number of cases, biplane transesophageal echocardiography adds morphological detail to the diagnosis of patent foramen ovale. The ability to size the actual opening may have therapeutic implications.

Doppler echocardiographic patterns of left ventricular filling in patients early after acute myocardial infarction.

Diastolic function is routinely assessed using Doppler-derived left ventricular (LV) filling patterns. Ratios between peak flow velocities during early filling and atrial contraction (E/A) of less than 1 are considered pathologic and diagnostic of impaired relaxation. Myocardial stiffness can normalize the E/A ratio, and thus, in some clinical settings, a normal E/A ratio may identify patients with high filling pressures. LV filling patterns were studied with Doppler echocardiography in 15 healthy subjects and 38 patients with recent acute myocardial infarction. The results were correlated with clinical and hemodynamic variables. E/A ratio less than 1 was found in 14 patients (37%) and in only 1 control subject; E/A ratio greater than 2 found in 5 patients (13%) and in only 1 control subject; 19 patients (50%) had an apparently normal E/A ratio. No correlation was found between LV filling pattern and ejection fraction or presence of diabetes or arterial hypertension. LV end-diastolic pressures were low to normal in patients with an E/A ratio less than 1 and were usually greater than 15 mm Hg in those with normal or abnormally increased (greater than 2) E/A ratios. Thus, an apparently normal E/A ratio in patients after myocardial infarction may identify those with more severe LV diastolic dysfunction and increased LV filling pressure.