New method of on-line quantification of regional wall motion with automated segmental motion analysis

We have recently developed an automated segmental motion analysis (A-SMA) system, based on an automatic "blood-tissue interface" detection technique, to provide real-time and on-line objective echocardiographic segmental wall motion analysis. To assess the feasibility of A-SMA in detecting regional left ventricular (LV) wall motion abnormalities, we performed 2-dimensional echocardiography with A-SMA in 13 healthy subjects, 22 patients with prior myocardial infarction (MI), and 9 with dilated cardiomyopathy (DCM). Midpapillary parasternal short-axis and apical 2- and 4-chamber views were obtained to clearly trace the blood-tissue interface. The LV cavity was then divided into 6 wedge-shaped segments by A-SMA. The area of each segment was calculated automatically throughout a cardiac cycle, and the area changes of each segment were displayed as bar graphs or time-area curves. The systolic fractional area change (FAC), peak ejection rate (PER), and filling rate (PFR) were also calculated with the use of A-SMA. In the control group, a uniform FAC was observed in real time among 6 segments in the short-axis view (60% +/- 10% to 78% +/- 9%), or among 5 segments in either the 2-chamber (59% +/- 12% to 75% +/- 16%) or 4-chamber view (58% +/- 13% to 72% +/- 12%). The variations of FAC, PER, and PFR were obviously decreased in infarct-related regions in the MI group and were globally decreased in the DCM group. We conclude that A-SMA is an objective and time-saving method for assessing regional wall motion abnormalities in real time. This method is a reliable new tool that provides on-line quantification of regional wall motion.

Predominant inner-half wall thickening of left ventricle is attenuated in dilated cardiomyopathy: an application of tissue Doppler tracking technique

The importance of the inner half (IH) of the left ventricular (LV) wall has been reported in hearts that contract normally. However, it is difficult to verify this fact in an in vivo human heart with clinical echocardiography. By using a recently developed tissue Doppler tracking technique, we could assess the systolic wall thickening of the IH and outer half (OH) of the LV wall in 11 normal and 7 dilated cardiomyopathic hearts. Percent wall thickening and the fractional contribution of the IH and OH to the transmural wall thickening were calculated. In healthy subjects, percent wall thickening of the IH, OH, and transmural wall of the left ventricle were 75.8% +/- 24.1%, 39.4% +/- 14.4% (P <.001 versus IH), and 57.6% +/- 17.6%, respectively. In patients with dilated cardiomyopathy, those values were 31.3% +/- 17.1%, 31.2% +/- 20.1% (not significant versus IH), and 31.2% +/- 16.5%, respectively. On the other hand, the fractional contributions of the IH and OH were 66.2% +/- 7.7% and 33.8% +/- 7.7% (P &lt.01 versus IH) in healthy subjects and 50.5% +/- 11.8% and 49.5% +/- 11.8% (not significant versus IH) in patients with dilated cardiomyopathy. Specifically, the IH contributed to the transmural wall thickening nearly twice as much as the OH did in healthy subjects, however, the predominance of IH contribution was attenuated in dilated cardiomyopathy. The tissue Doppler tracking technique is useful in assessing the IH and OH LV wall thickening separately in the clinical situation.

Usefulness of transesophageal echocardiographic monitoring in transluminal endovascular stent-graft repair for thoracic aortic aneurysm

The endovascular stent-graft has been devised for the treatment of thoracic aortic aneurysm (TAA) to reduce complications associated with conventional surgical repair. The present study assessed the usefulness of transesophageal echocardiography (TEE) for intra- and post-operative examinations in patients treated with transluminal endovascular stent-graft repair for TAA. Nine patients with TAA and 2 with chronic type B aortic dissection were studied. Immediately after stent-graft deployment, perigraft leakage was evaluated with both intraoperative TEE and aortography. In 9 of 11 patients, TEE and aortography immediately after stent-graft deployment revealed the same perigraft leakage results. TEE might therefore be useful for evaluating perigraft leakage and thrombus formation after stent-graft repair for TAA and could be an alternative to aortography, especially for patients with renal dysfunction who have the possibility of contrast agent-induced complications.

Assessment by transesophageal echography of atherosclerosis of the descending thoracic aorta in patients with hypercholesterolemia

This study assesses atheromatous lesions and aortic stiffness of the descending thoracic aorta (DTA) in patients with hyperlipidemia by transesophageal echography (TEE) and investigates the relations between atherosclerotic lesions and aging or serum cholesterol levels in these patients. Subjects included 16 patients with familial hypercholesterolemia (FH), 15 non-FH hyperlipidemic patients (non-FH), and 17 age-matched normal subjects. With use of TEE, the DTA was divided into 4 longitudinal portions of equal length, and the atheromatous lesions of each portion of DTA were scored according to their character and extension by biplane 2-dimensional TEE. The scores of atheromatous lesions from all 4 portions were added together to give the total atheromatous score. Then, after measuring the instantaneous dimensional changes of DTA in a cardiac cycle by M-mode TEE and blood pressure (BP) by a cuff method, we calculated the aortic stiffness parameter beta = ln(systolic BP/diastolic BP)/([Dmaximum - Dminimum]/Dminimum). The beta was significantly higher in FH and non-FH subjects than in normal subjects. In both FH and non-FH subjects, the total atheromatous score correlated with total serum cholesterol levels (r = 0.64 [p <0.01]; r = 0.58 [p <0.05], respectively). There were significant correlations between age and beta in all 3 groups (FH, r = 0.67 [p <0.005]; non-FH, r = 0.53 [p <0.05]; normal subjects, r = 0.49 [p <0.05]), and the slopes of the regression lines of FH and non-FH subjects were much steeper than those of normal subjects. The incidence of atherosis in the DTA was significantly higher in hyperlipidemic patients than in normal subjects, even among the younger members of the hyperlipidemic population with progressive aortic stiffness.

Echographical assessment of the early stage of experimental atherosclerosis of the descending aorta in rabbits

To assess the early stage of atherosclerosis of the thoracic descending aorta, we evaluated morphological atheromatous lesions (atherosis) and the stiffness parameter of the artery (beta; sclerosis) in 24 male rabbits using echography. Male Japanese white rabbits weighing 2.5-3.0 kg were fed a diet containing 1% cholesterol for 7 (n = 8) or 14 weeks (n = 8). Rabbits fed a normal diet were used as controls (n = 8). Atheromatous lesions were evaluated with intravascular ultrasound (IVUS: Aloka, 20 MHz, 6F). We also calculated beta using M-mode echography (7.5 or 10 MHz) and direct aortic pressure measurement. Thickening of the intima-media complex was clearly observed with IVUS in the 14-week group but was not detected in the others. Histologically, only a thin layer of foamy cells on the intima (thickness < 20 microns) was observed in the 7-week group. The value of beta was significantly increased in both the 7-week (4.7 +/- 2.2) and 14-week groups (4.5 +/- 0.8) compared with controls (1.7 +/- 0.9, both p < 0.01). These results suggest that the development of atherosis might be preceded by vascular sclerosis during the early stage of atherosclerosis when the serum cholesterol level is high: at a time when the thin layer of foamy cells could not be detected by conventional IVUS.

Improvement of atherosclerosis and stiffness of the thoracic descending aorta with cholesterol-lowering therapies in familial hypercholesterolemia

The thoracic aorta is frequently involved in atherosclerotic lesions associated with familial hypercholesterolemia (FH). Transesophageal echocardiography (TEE) allows quantitative evaluation of the wall properties of the thoracic aorta. Using TEE, we tested whether atherosclerosis of the thoracic aorta in FH could be improved by cholesterol-lowering therapies. The subjects investigated were 22 FH patients and 22 age-matched normal subjects. The descending aorta (DA) was divided into four longitudinal portions of equal length. Atheromatous lesions of each portion of the DA were scored by character and extension of lesions by biplane two-dimensional TEE. The scores of atheromatous lesions from all four portions of the DA were added together to give the total atheromatous score (TAS). We also measured instantaneous dimensional changes of the DA in a cardiac cycle by M-mode TEE and blood pressure by a cuff method and calculated the stiffness parameter beta (In[SBP/DBP]/[Dmax-Dmin]/Dmin), where SBP is the systolic arterial blood pressure, DBP is the diastolic arterial blood pressure, Dmax is the maximum aortic dimension during the ejection period, and Dmin is the minimum aortic dimension during the preejection period. TAS was higher in FH (3.70 +/- 1.32) than normal (0.62 +/- 0.54, P < .0001) subjects. Beta in FH (10.35 +/- 4.87) was greater than in normal (5.10 +/- 1.25, P < .0001) subjects, but there were no significant differences of DA dimensions between the groups. In both normal subjects and FH patients, beta correlated with age (r = .52, P < .02 and r = .59, P < .005, respectively). In FH patients, beta and TAS correlated well with pretreatment total cholesterol levels (r = .43, P < .05 and r = .60, P < .005, respectively). In 12 of 22 FH patients, strict cholesterol-lowering therapies with diet and cholesterol-lowering drugs (pravastatin and probucol) were undertaken for 13 months. Cholesterol levels were significantly decreased from 333 +/- 45 to 219 +/- 39 mg/dL (P < .0001); this was associated with significant decreases in beta and TAS (from 9.88 +/- 5.03 to 7.88 +/- 3.92, P < .005, and from 3.61 +/- 1.50 to 2.94 +/- 1.22, P < .0005, respectively). In FH patients, the incidence and severity of morphological and physiological atherosclerosis of the DA were significantly higher than in age-matched normal subjects. A significant regression of atherosclerosis was achieved by strict cholesterol-lowering therapies in relatively young FH patients.

Effects of nifedipine on mechanical properties of the normal and atherosclerotic descending aorta assessed by transesophageal echocardiography

We assessed the effects of calcium ion (Ca++) entry blockade (nifedipine) on the static elastic properties of the thoracic descending aorta in 60 subjects classified into 4 groups according to age and complications. The stiffness index (beta), which expresses the mechanical properties of the arterial wall, was calculated from the dimensional changes of the thoracic aorta by transesophageal echocardiography and blood pressure was determined by conventional cuff method. After administration of nifedipine, beta was significantly decreased in all groups. There was a significant correlation between beta at rest and the value of a decrease in beta after nifedipine in the relatively younger and the older groups with complications, but no significant correlation was observed in the older group without complications. Nifedipine directly reduces the stiffness of the descending aorta. The effect is stronger in relatively younger subjects, especially in subjects with risk factors of atherosclerosis and stiff descending aorta at rest. These results suggest that there may be a reversible sclerotic property of the descending aorta, probably caused by high smooth muscle tone before an irreversible atherosclerosis occurs in patients with risk factors promoting atherosclerosis.

Assessment of flow profile of left anterior descending coronary artery in hypertrophic cardiomyopathy by transesophageal pulsed Doppler echocardiography

This study assessed the flow velocity profiles of the left anterior descending coronary artery (LAD) in 7 patients with nonobstructive hypertrophic cardiomyopathy (HC) and in 6 normal subjects by transesophageal pulsed Doppler echocardiography, and evaluated their characteristics and the hemodynamic determinants. Systolic peak flow velocity of the LAD (7 +/- 30 cm/sec) was significantly lower in patients with HC than in normal subjects (34 +/- 11 cm/s, p < 0.05), and there was a significant inverse correlation between systolic peak flow velocity and the thickness of the ventricular septum (r = 0.81, p < 0.01). In 2 cases of HC with ventricular septal thickness of > 20 mm, a remarkable systolic reverse flow was observed in the LAD. However, there was no significant difference in diastolic peak flow velocity between HC and normal subjects. During early diastole, the acceleration time of LAD flow velocity was significantly prolonged (210 +/- 67 vs 95 +/- 15 ms, p < 0.01) and the acceleration rate was significantly decreased (3.6 +/- 2.0 vs 6.6 +/- 1.8 m/s2, p < 0.02) in patients with HC. The time constant of the left ventricular pressure decay was significantly prolonged in patients with HC (55 +/- 6 ms) compared with normal subjects (39 +/- 2 ms, p < 0.001). In HC, increased intramural perivascular pressure of the thickened ventricular septum during systole may be attributed to systolic LAD flow pattern. However, the early and mid-diastolic LAD flow pattern may be affected by impaired left ventricular relaxation.

Advances in transesophageal echocardiography for the evaluation of atherosclerotic lesions in thoracic aorta--the effects of hypertension, hypercholesterolemia, and aging on atherosclerotic lesions

We assessed atherosclerotic lesions in the thoracic aorta in 166 consecutive patients (aged 56 +/- 13 years) by transesophageal echocardiography, and investigated the influences of hypertension, hypercholesterolemia and age on the prevalence of such lesions. Satisfactory images were obtained of all the thoracic aorta, except for a small part of the ascending aorta, by use of a biplane transesophageal probe. We defined atherosclerotic lesions as increased echogenicity of the intima (intimal thickening), raised plaque, calcification, ulceration, or aneurysms. Lesions were observed in 97 patients (58%). The incidence of lesions in patients with hypertension (81%) or hypercholesterolemia (80%) was significantly greater than in those without both conditions (37%, p less than 0.005). The incidence of lesions was significantly increased among patients over 60 years old compared with that in patients under 60 (76% vs 42%, p less than 0.005). Patients without either hypertension or hypercholesterolemia showed a marked increase in the incidence of lesions with age (16% at less than 60 yrs vs. 67% at greater than 60 yrs), and no significant influence of these conditions on the incidence of lesions was found in patients over 60. We conclude that hypertension and hypercholesterolemia might be important risk factors for the development of atherosclerotic lesions in the thoracic aorta in relatively younger patients. Age appears to become a more important determinant of such lesions in Japanese patients over 60 years old irrespective of blood pressure and serum cholesterol levels.