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Biomedical subjects

D Kawanishi

Publications and source records attributed to D Kawanishi.

12 recordsLinked to original sources
PubMed1998

Comparison of intracoronary Doppler guide wire and transesophageal echocardiography in measurement of flow velocity and coronary flow reserve in the left anterior descending coronary artery.

BACKGROUND: The intracoronary Doppler tipped guide wire has been shown to be highly accurate in the measurement of coronary flow velocity (CFV). Recent studies have indicated that blood flow velocity in the left anterior descending coronary artery (LAD) can be determined by transesophageal echocardiography (TEE). The purpose of this study was to compare flow velocity recordings and coronary flow reserve measurements in the LAD by TEE with those obtained by Doppler guide wire. METHODS AND RESULTS: The study population consisted of 14 patients with chest pain and normal coronary arteriograms. After routine coronary arteriography was performed, a 0.014-inch Doppler guide wire was advanced into the proximal part of the LAD. After baseline measurement of coronary flow velocity (CFV) was obtained, 140 microg/kg/min adenosine was administered intravenously for 3 minutes, and the flow velocity was recorded. TEE was performed within 24 hours of the cardiac catheterization. After baseline measurements of CFV in the LAD, heart rate, and blood pressure were obtained, 140 microg/kg/min adenosine was administered intravenously, and the CFV was recorded. Coronary flow reserve was calculated as the ratio of the peak diastolic CFV during adenosine infusion to the peak diastolic CFV at baseline. A good correlation was found (r = 0.91, p < 0.0001) between CFV by Doppler guide wire and that determined by TEE. A good correlation was also found between the coronary flow reserve assessed by Doppler guide wire and that determined by TEE (r = 0.92, p < 0.0001). CONCLUSION: Our data indicate that CFV and coronary flow reserve in the LAD can be accurately measured by transesophageal echocardiography.

Adult↗
PubMed1991

Management of valvular heart disease: an illustrative cases approach.

As indicated by the 22 illustrative cases included in this monograph, a stepwise approach to the assessment of valvular heart disease provides the information necessary to make good clinical decisions. The ECG and chest x-ray add useful information to the history and physical examination. Echocardiography, Doppler, and color flow Doppler techniques have an important role in defining the presence and severity of valvular stenosis and regurgitation. Nuclear techniques provide useful information about global biventricular systolic function, regional wall motion, and myocardial perfusion. Exercise testing is most valuable in confirming objectively the patient's functional status and exercise tolerance. Newer imaging techniques, such as cine CT and MRI, are capable of displaying and measuring cardiac chamber size and myocardial thickness; however, visualization of the cardiac valves and demonstration of flow abnormalities are difficult, limiting the current usefulness of these techniques in patients with valvular heart disease.

Adult↗
PubMed1988

Impaired fibrinolysis in coronary artery disease.

We assessed endogenous endothelial-dependent fibrinolysis in 99 subjects with coronary artery disease (CAD) documented by angiography and in 28 control subjects with normal coronary arteries on angiography. We used specific, sensitive assays for plasma tissue-type plasminogen activator (t-PA) antigen, t-PA activity, plasminogen activator inhibitor (PAI) activity, plasminogen, and alpha-2 plasmin inhibitor (alpha-2 PI). Mean PAI activity was significantly higher, and mean t-PA activity after venous occlusion of the upper arm (a standard test of the capacity of vascular endothelium to release t-PA) was significantly lower in subjects with CAD than in subjects with normal coronary arteries. The mean increment in t-PA antigen after venous occlusion was significantly lower than normal in subjects with CAD with onset of symptoms before age 45 years. Subjects with CAD had a significantly increased mean plasma fibrinogen level compared with control subjects, and a significant positive correlation was observed between PAI activity and plasma fibrinogen in subjects with CAD. No significant abnormalities of plasminogen or alpha-2 PI were observed in any subset of subjects with CAD. These data support an association between impaired fibrinolysis and CAD, with contributions from both increased PAI activity and in younger subjects from reduced endothelial t-PA release.

Antigens↗
PubMed1986

Effects of nifedipine on hemodynamics and cardiac function in patients with normal left ventricular ejection fraction already treated with propranolol.

The interaction between nifedipine and propranolol on cardiac hemodynamics and function was investigated in 9 patients with normal left ventricular (LV) function who were undergoing cardiac catheterization for complaints of chest pain. Only 2 patients had angiographic evidence of significant coronary artery disease but no patient had clinical evidence of ischemia during the study. All patients were pre-treated with propranolol, 30 to 320 mg/day (mean +/- standard deviation 210 +/- 122); the propranolol serum level ranged from 43 to 246 ng/ml (mean 203 +/- 62). The administration of nifedipine resulted in a decrease in blood pressure (from 94 +/- 11 to 85 +/- 13 mm Hg, p less than 0.05), increase in heart rate (from 59 +/- 6 to 65 +/- 7 beats/min, p less than 0.05), and an increase in both mean right atrial and mean pulmonary artery wedge pressures (from 8 +/- 3 to 9 +/- 3 mm Hg and from 13 +/- 3 to 14 +/- 4 mm Hg, respectively, both p less than 0.05). Cardiac index increased (from 2.3 +/- 0.3 to 2.7 +/- 0.2 liters/min/m2, p less than 0.01). Stroke volume index also increased significantly (from 39 +/- 5 to 43 +/- 6 ml/m2) and systemic vascular resistance decreased (from 1,715 +/- 369 to 1,255 +/- 271 dynes s cm-5, p less than 0.01). No significant change was noted in pulmonary vascular resistance (148 +/- 94 vs 140 +/- 62 dynes s cm-5), LV stroke work index (44 +/- 9 vs 42 +/- 10 g-m/m2), LV end-diastolic pressure (15 +/- 2 vs 16 +/- 2 mm Hg).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Differentiation between acute and healed myocardial infarction by signal averaging and color encoding two-dimensional echocardiography.

To evaluate the ability of a system developed in our laboratory to differentiate between acute and healed myocardial infarction (MI), gated 2-dimensional echocardiography was performed in 10 patients with recent MI (within 48 hours) and 10 patients with healed MI (later than 4 weeks). The 2-dimensional echocardiographic images were digitized using a Datacube VG-120 videoframe digitizer and each digitized videoframe (320 X 240 matrix) was transmitted using a high-speed serial data link to a second computer and stored on floppy disc. Five gated video frames of each patient were time-averaged to give a smoothed digitized image. This image was displayed on high-resolution color monitor connected to a color graphic subsystem. Sixty-four colors indicated pixel intensity. The exact pixel value at any given location was determined using a high-resolution light pen. Color or pixel values were not significantly different between the area of acute MI (pixel intensity 23 +/- 3, mean +/- standard deviation) identified by a regional wall motion abnormality, and the adjacent normal muscle (23 +/- 4). In each patient with healed MI, an increase in color intensity and pixel value (43 +/- 6) was seen in the area of MI (i.e., area of regional wall motion abnormality) compared with adjacent normal muscle (23 +/- 2) (p less than 0.001). These preliminary data in selected patients indicate that this technique enables differentiation between acute and healed MI. It could be of value in management of patients with suspected MI.

Acute Disease↗
PubMed1984

Identification of the increased frequency of cardiovascular abnormalities associated with mitral valve prolapse by two-dimensional echocardiography.

Two-dimensional echocardiography (2-D echo) was performed in 86 consecutive patients with mitral valve prolapse (MVP) and in 25 normal subjects. In normal subjects, mitral leaflet thickness was 3.5 +/- 0.8 mm (mean +/- standard deviation) and the mitral leaflet thickness to aortic wall thickness ratio was 1.0 +/- 0.2. Patients with MVP were separated into 2 groups: those with normal mitral thickness (less than or equal to mean + 2 SD observed in normal subjects, i.e., less than or equal to 5.1 mm) and normal mitral thickness to aortic wall thickness ratio (less than or equal to mean + 2 SD observed in normal subjects, i.e., less than or equal to 1.4) (group I) and others in whom these values were increased (group II). In group I, mitral thickness was 3.6 +/- 0.6 mm and mitral thickness to aortic wall thickness ratio was 1.1 +/- 0.1, and in group II, mitral thickness was 8.8 +/- 1.2 mm and mitral thickness to aortic wall thickness ratio was 2.2 +/- 0.5. The only significant cardiovascular abnormalities in group I were mitral regurgitation in 2 patients and tricuspid valve prolapse in 1 patient. In group II, 7 patients had clinically significant mitral regurgitation, 8 had aortic root abnormalities, 4 had tricuspid valve prolapse and 6 had Marfan's syndrome. Cardiovascular abnormalities were present in 60% (18 of 30) of patients in group II and in 6% (3 of 56) of patients in group I (p less than 0.001). Two-dimensional echo enabled the identification of a subset of patients with MVP who had thickened mitral leaflets. These patients had an increased incidence of cardiovascular abnormalities.

Adult↗
PubMed1983

Application of 2-dimensional contrast studies during pericardiocentesis.

Two-dimensional echocardiographic contrast studies were performed in 16 patients with pericardial effusion. A 4-chamber view was obtained by positioning the transducer at the apex. The exploratory needle was visualized in 9 patients. Five milliliters of saline solution were injected through the exploring needle and a cloud of echoes indicated its position. Microbubbles were seen in all 16 patients. This technique enabled the operator to identify that the needle was inadvertently in the left ventricle in 2 patients and in the right ventricle in 1. Furthermore, in 2 patients, when fluid could not be aspirated, the contrast study confirmed that the needle was in the pericardial sac; in both cases, pericardial fluid could be aspirated with slight manipulation of the needle. In a patient with a stab wound a negative contrast effect indicated the probable site of laceration. Thus, 2-dimensional contrast echocardiography was useful in locating needle position, which facilitated pericardiocentesis.

Adult↗
PubMed1983

Echocardiographic detection of pneumomediastinum and pneumopericardium: the air gap sign.

Six patients referred for echocardiographic evaluation in whom an unusual echocardiographic sign resulted from air within the mediastinum or pericardium are described. Three patients had a pneumomediastinum that occurred after chest trauma and three patients had a pneumopericardium induced during a therapeutic pericardiocentesis. Important features included a broad band of echoes (air) recorded during held respiration which obscured the normal cardiac structures and dropout (gap) of echoes posteriorly. Between the cyclic appearance of the "air gap" sign, intracardiac structures were normally visualized. Echocardiographic recording of the air gap sign was identical in the six cases; it disappeared after resolution of clinical signs and symptoms of the pneumopericardium or pneumomediastinum. The pattern most likely resulted from air within the anterior mediastinum or pericardium interfering with the echographic beam and resulted in a cyclic appearance from systole to early diastole as the air was displaced by the changing cardiac size. Recognition of the air gap sign can be helpful in evaluating patients for pneumomediastinum or pneumopericardium after thoracic trauma.

Air↗