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Biomedical subjects

Y Yokote

Publications and source records attributed to Y Yokote.

At least 55 records · Page 3Linked to original sources
PubMed1997

[Serratia marcescens prosthetic mitral valve endocarditis associated with hemolytic anemia].

A 57-year-old female who had been performed mitral valve replacement (MVR) using 31 mm prosthetic valve 32 months before entered the hospital for the evaluation of long standing severe hemolytic anemia without infectious sign. Transesophageal echocardiogram revealed a moderate sized vegetation on the atrial site of the prosthetic valve. The size and number of the vegetation were increased after deterioration of infectious illness. Blood culture grew serratia marcessans and alpha-hemolytic Streptococcus. Re-MVR was carried out with the diagnosis of prosthetic valve endocarditis (PVE). As the symptom of PVE, hemolytic anemia without infectious sign is a rare condition. TEE is an useful method to make diagnosis of PVE by detecting the vegetations and evaluating their change of size and methods and to evaluate the effectiveness of the treatment.

Anemia, Hemolytic↗
PubMed1996

[Papillary muscle rupture complicating acute myocardial infarction--treatment with mitral valve replacement and coronary bypass surgery in acute phase].

Complete rupture of a papillary muscle following acute myocardial infarction is a severe complication that is typically associated with acute left ventricular failure, pulmonary edema, and relentless clinical deterioration. The reported mortality rates without surgical intervention is almost 90%, therefore, prompt operation without prolonged attempts at medical stabilization is the key to decrease operative mortality. Although the complete coronary revascularization in conjunction with mitral valve replacement is advocated in the western medical academic society, there is only a few case of conjunct surgery has been reported in Japan. Three successful cases of conjunct surgery of mitral valve replacement and coronary complete revascularization in acute phase within one week from the onset of acute myocardial infarction (AMI) are described. There were one male and two female patients with an average age of 60-year-old (range 48-67), who developed cardiogenic shock and admitted to our hospital. The average interval between onset of AMI and the appearance of mitral regurgitation (MR) was 38 hours, and that of the appearance of MR and admission was 40 hours. Surgeries were performed within 26 hours (average 13 hours) after admission. The mitral valve was replaced with a mechanical valve (St. Jude Medical Valve) and a complete coronary revasculatization was done using saphenous vein graft. The average period of operation time and aortic cross clamping time were 6 hours 22 minutes and 109 minutes respectively. The average number of coronary grafting was 2.3 (range 1-3). Postoperative recovery from cardiogenic shock was uneventful in all three patients. The average periods of ICU stay and hospital stay were 5 days and 43 days respectively. All patients have regained their social activities with mean follow up period of 52 months. Since ischemic heart disease remains the leading cause of death in such patients, it is suggested that complete coronary revascularization should be performed immediately in conjunction with valve replacement even in the acute phase after onset of AMI.

Aged↗
PubMed1995

[Left atrial ball thrombus in the SLE patient without organic mitral lesion].

A case of 77-year-old female patient with the left atrial ball thrombus without organic mitral valve lesion is reported. She had a history of SLE for one year and experienced pericarditis 2 months before this admission. A 2-D echo examination at that time did not show any abnormal shadow in the left atrium. The repeated 2-D echo on this admission demonstrated peduncular left atrial thrombus of 2 x 1.5 cm in size. Surgical removal of the thrombus was performed successfully. Her cardiac rhythm was atrial fibrillation, but other possible factors related to the intracardiac thrombus formation such as bradycardia, left atrial dilatation or low cardiac output were not noted. Although lupus anticoagulant and anticardiolipin antibody were negative before the operation, participation of SLE in formation of the left atrial thrombus was highly suspected.

Aged↗
PubMed1995

[Clinical result of left ventricular free wall rupture resulting from acute myocardial infarction].

We have treated 10 patients of left ventricular free wall rupture (LVFWR) resulting from acute myocardial infarction (AMI) in our intensive care unit (ICU) from Oct. 1984 to Dec. 1993. Nine of 10 patients underwent surgical repair, however, one patient was treated with pericardocentetesis in ICU and fibrin-glue was infused into the pericardial space (fibrin-glue therapy:FG therapy). The survival rate of surgical repair was only 33% (3/9), especially that was only 17% (1/6) when cardiopulmonary bypass (CPB) was required. One patient (49-year-old, male) suffered from cardiogenic shock following AMI in the posterior wall was performed coronary angioplasty (PTCA) in emergency and IABP support was required. Fourth day after PTCA, a sudden hemodynamical collapse had occurred on this patient due to cardiac tamponade. This patient was treated with pericardiocentetesis in ICU and FG therapy was performed, because all surgical teams were occupied in their operations. After FG therapy hemodynamical stability was obtained, the patient was survived and discharged at 2 months after LVFWR. In conclusion, the surgical result of LVFWR is still not good, especially when CPB was utilized. FG therapy was successful in one patient, suggesting FG therapy can be an alternative therapy for LVFWR when surgical team is not available.

Aged↗
PubMed1993

Reduction of reperfusion injury by recombinant human superoxide dismutase administered intravenously just prior to reperfusion.

The reduction of reperfusion injury by intravenous administration of recombinant human superoxide dismutase (r-hSOD) was evaluated in a dog model. Two hours of left anterior coronary artery clamping were followed by 30 min of partial reperfusion and 30 min of full reperfusion. In the SOD group, r-hSOD (100,000 U/kg) was given intravenously 5 min before reperfusion. Measured left ventricular (LV) segments were classified thermographically by temperature drop into central (> or = 2 degrees C) and marginal (< 2 degrees C) areas. The regional LV functions were evaluated by percentages of both segmental (%SS) and active (%AS) shortening. In the central area, the %SS values after reperfusion were -9% in the control group and -3% in the SOD group (p < 0.05). The respective %AS values were 6 and 29% (p < 0.01). In the marginal area, both groups had %SS values of -3% and respective %AS values of 34 and 22% (all not significant) after reperfusion. In the central area, there was significantly better LV function recovery in the SOD group than in the control group.

Animals↗
PubMed1993

[Cerebral protection with selective cold blood cerebral perfusion by gravity during aortic arch reconstruction].

Selective cold blood cerebral perfusion by gravity using specially designed reservoir with a built-in heat exchanger was applied to 30 consecutive patients who required aortic arch reconstruction. Rectal and brain temperature during cerebral perfusion were maintained at 22 degrees C and 16 degrees C respectively. Patients were divided into two groups according to postoperative condition of consciousness. Twenty three patients had uneventful recovery of consciousness (Group-1), and 7 patients showed delayed recovery or disturbance of consciousness (Group-2). Age, sex, causes of aneurysm, rectal temperature and conditions of cerebral perfusate were not statistically significant in both groups. Selective cerebral perfusion time in Group-1 was 68 +/- 36 min and 85 +/- 31 min in Group-2 (statistically not significant). Extracorporeal circulation time in Group-2 (243 +/- 61 min) was significantly longer than in Group-1 (187 +/- 56 min) (p < 0.05). Five of seven patients (71%) in Group-2 were in shock pre- or early post-operative period contrary to 0% in Group-1 (p < 0.001). These results suggest that selective cold blood cerebral perfusion protects effectively the brain during aortic arch reconstruction in the patients without hemodynamic deterioration.

Adult↗
PubMed1992

Evaluation of biplane color Doppler transesophageal echocardiography in 200 consecutive patients.

BACKGROUND: We developed the first biplane transesophageal echocardiography (TEE) probe with two orthogonal transducers, allowing synchronous side-by-side displays of the heart on a monitor TV, and compared its diagnostic value with that of conventional single-plane TEE using commercially available Doppler equipment in 200 consecutive patients intraoperatively, perioperatively, or on an outpatient basis. METHODS AND RESULTS: Insertion was easy, except in one patient with a mediastinal tumor, and no complications were encountered. Both transverse and longitudinal scans allowed correct identification of true and false lumina in all 30 aortic dissection examinations, but longitudinal scanning was slightly superior in detecting types I and III entry sites. Three entries that were not detected by transverse scanning (two of DeBakey type I and one of type III) were visualized by longitudinal scanning. Among 37 cases of mitral regurgitation (MR), longitudinal scans were significantly superior (p less than 0.05) in revealing multiple jets (nine compared with two with transverse scanning). Although both planes yielded almost identical mean values for the maximum jet areas, a difference of over 50% in jet area size on the two planes was observed in 19 cases. The measured jet areas showed significant correlation with the angiographic MR grading, especially for the larger of the biplane measurements (p less than 0.01), and different grades showed little overlap. Longitudinal images increased the acoustic window of the heart and aorta from the esophagus. Moreover, longitudinal scanning provided good visualization of both ventricular outflow tracts, the ascending aorta, main pulmonary artery, and superior vena cava. CONCLUSIONS: This modality greatly facilitates a three-dimensional comprehension of cardiovascular lesions and flow dynamics, especially in aortic dissection and MR, and its safety was demonstrated. Our data demonstrate the usefulness of this new technique in comparison with conventional single-plane TEE.

Aortic Dissection↗
PubMed1992

Outcome of Stanford type B acute aortic dissection.

BACKGROUND: The optimal timing of surgery in patients with Stanford type B aortic dissection remains controversial. This report reviews retrospectively early and long-term outcomes of patients with Stanford type B acute aortic dissections at our institute. METHODS AND RESULTS: From April 1979 through January 1991, 75 patients were diagnosed with Stanford type B aortic dissection, and 58 of them were hospitalized within 2 weeks from onset. They were treated initially as follows: emergent surgery was performed in 13 patients for rupture or impending rupture, and the remaining 45 were treated medically. In the former group, nine patients (69%) died; in the latter, eight (18%) needed surgery because of enlargement or rupture of the aneurysm in the follow-up period, and only one of these (13%) died. Of the other 37 patients treated medically, three (8%) died within 2 weeks and seven died (19%) in the chronic phase, four of them from rupture. Among 42 discharged patients initially treated medically, rupture occurred in 11.9% (five of 42). CONCLUSIONS: In acute-phase cases, surgical mortality is so high that medical treatment is preferable unless there are major complications. However, even in patients who had undergone successful initial medical treatment, expansion of the aneurysm, requiring surgery, often occurred. If careful observation reveals any sign of expansion, because elective surgery can be performed at low risk, it should be considered as soon as possible before a rupture develops.

Actuarial Analysis↗
PubMed1992

Intraoperative echocardiography for diagnosis and treatment of aortic dissection. Utility of color flow mapping for surgical decision making in acute stage.

In the past eight years until July 1992, 92 patients were admitted in the acute state of aortic dissection within two weeks from the onset of symptoms. 41 were diagnosed as Stanford type A and 51 were type B by transthoracic and transesophageal echography, computer tomography, and surgery. Sensitivity of transesophageal echography to detect the intimal flap and the false lumen was 97.6% in patients with Stanford type A and 100% in patients with Stanford type B. The surgical decision making has been mostly depending on the transesophageal echographic diagnosis. When the intimal flap was detected in the ascending aorta (Stanford type A) surgery was performed in emergency regardless of any evidence of rupture, cardiac tamponade, and severe aortic regurgitation. When the aortic dissection was detected only in the descending aorta (Stanford type B) the main course of therapeutic strategy in our institute was medical treatment. Surgery was performed on 37 patients of type A and nine patients of type B with mortality of 18.9% and 55.5% respectively. Four patients of type A and 42 patients of type B were treated medically with a mortality of 75.0% and 2.2% respectively. The relatively large leakages from the anastomosis of the aortic clamp site were repaired secondarily in two patients, and fenestration of the superior mesenteric artery was performed on one patient due to ischemia of the small intestine depending on the intraoperative direct scanning of color flow mapping. Coronary artery involvement of dissection was strongly suspected in two patients by intraoperative transesophageal echography and aortocoronary bypass grafting was performed on these patients. Perfusion problems was encountered in five of 37 patients with type A aortic dissection (13.5%) during cardiopulmonary bypass. Intraoperative transesophageal echography could clearly detect the hemodynamic changes in the descending aorta resulting from inadequate perfusion which was useful for the management of perfusion control during cardiopulmonary bypass. Secondary repair of the aortic arch was required due to ischemia of the aortic arch vessels in two patients after the primary surgery. The extension of the dissection into the aortic arch vessels can be promptly diagnosed with the combination of transesophageal echography and transcutaneous echography. In conclusion, transesophageal Doppler echography is the most rapid diagnostic tool for decision making in acute aortic dissection, and intraoperative transesophageal echo can provide useful information to resolve the perfusion difficulties during cardiopulmonary bypass.(ABSTRACT TRUNCATED AT 400 WORDS)

Acute Disease↗
PubMed1992

[Estimation of peripheral metabolism under cardiopulmonary bypass by measuring ketone bodies, lactate, and pyruvate].

Both ketone body ratio (KBR) and pyruvate/lactate ratio (P/L) are metabolic indicators related to NAD-linked dehydrogenase system according to the REDOX THEORY. In order to estimate the peripheral metabolic state under the cardiopulmonary bypass (CPB) which is considered to be a moderate and controllable shock state, we measured the pyruvate (P), lactate (L) and ketone bodies (acetoacetate [ACA], 3-hydroxybutyrate[HOB]) pre, during, and post-CPB in 20 open heart surgical patients (Group 1). We also measured ketone bodies in another group (Group 2: 22 patients) of elective coronary artery bypass surgery (CABG). Five patients in Group 2 who developed postoperative organ failure (Group 2-A) were compared with the other 17 cases with uneventful postoperative course (Group 2-B). In Group 1, P and L concentrations progressively increased until the end of CPB, thereafter decreased (P less than 0.001). HOB and TKB significantly increased immediately after the start of CPB, afterward which declined during CPB and returned to the control level after CPB. Both KBR and P/L regression analysis reveal the significant correlation between P/L and KBR (r = 0.51, P less than 0.001). KBR at 1 hour after CPB returned to the control level, however, P/L at 1 hour after CPB still stayed in the significant lower level than the control (P less than 0.001). KBR at the aortic declamping in group 2-A was significantly lower than that in group 2-B. In conclusion, P/L and KBR changed in relation to hemodynamic change during CPB.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Hemodynamic response to dietary sodium loading in essential hypertension studied with Doppler echocardiography.

The cardiac response to dietary salt loading was assessed by Doppler echocardiography during various sodium intakes (52-345 mEg per day) in 30 patients with essential hypertension. The Mitral flow velocity integral in the rapid filling phase (IntR) and the atrial contraction phase (IntA) was measured from the transmitral flow pattern, and the sum of IntR and IntA (IntR + IntA), the ratio of IntA to IntR (IntA/IntR), cardiac output (CO) and total peripheral resistance (TPR) were calculated. With salt loading, the mitral flow pattern remained almost unchanged in the nonsalt-sensitive (NSS) patients. Fourteen of the 19 salt-sensitive (SS) patients showed significant increases in IntR + IntA and CO with salt loading (IntR + IntA, from 13.9 +/- 2.8 to 17.9 +/- 3.6 cm, p less than 0.01; CO, from 6021 +/- 2130 to 8305 +/- 1699 ml/min, p less than 0.01), and were termed "salt-sensitive CO-dependent" (SS [COdep]), suggesting that the apparent pressor response to sodium loading was mediated by an increased CO. In the remaining five SS patients termed "salt-sensitive CO-independent" (SS [COindep]), IntA/IntR increased significantly with sodium repletion (from 0.66 +/- 0.23 to 0.90 +/- 0.31, p less than 0.01), without a significant change in IntR + IntA. Increments in IntA/IntR observed in the SS [COindep] patients were considered to be due to an elevation of total peripheral resistance (TPR), since changes in IntA/IntR were significantly correlated with those in TPR in all subjects (r = 0.617, p less than 0.01).

Adult↗
PubMed1991

[Regional myocardial perfusion and function after coronary bypass surgery: evaluation using handgrip exercise Doppler echocardiography].

To evaluate myocardial perfusion and function of the interventricular septum after coronary artery bypass surgery, 29 patients with internal mammary artery grafts (IMAG) were examined using handgrip exercise Doppler echocardiography. IMAG flow was measured by color flow Doppler. Septal excursion and percent thickening of the interventricular septum during systole were measured as indicators of regional left ventricular function by M-mode echocardiography. Myocardial perfusion was estimated by thallium-201 exercise myocardial scintigraphy using a treadmill. 1. At rest, there were no significant correlations between IMAG flow and septal excursion and percent thickening or myocardial perfusion. 2. After the isometric handgrip exercise test, IMAG flow increased 20.0 +/- 3.9% from at rest, and the percentage of change in IMAG flow correlated significantly with changes in septal excursion (r = 0.63) and percent thickening (r = 0.72). It was found that a response of bypass graft flow to exercise has a correlation with contractility of cardiac muscle. 3. The rate of increase in IMAG flow in patients with normal myocardial scintigraphic findings (31.8 +/- 6.2%) was higher than that in patients with ischemia (15.3 +/- 5.6%) or infarction (15.0 +/- 11.3%). 4. A greater increase of percent thickening was observed in patients with normal exercise myocardial scintigraphic findings. These results suggest that the responses of the bypass graft flow to handgrip exercise may reflect viability and contractility of cardiac muscles perfused by the graft. Thus, exercise Doppler echocardiography is useful for evaluating regional myocardial perfusion and function of the interventricular septum after coronary artery bypass surgery.

Adult↗
PubMed1991

[Diagnosis of acute aortic dissection with transesophageal echocardiography and results of surgical treatment].

Forty-four consecutive patients with acute aortic dissection from April 1987 to April 1990 were diagnosed with the use of transesophageal echocardiography (TEE) and treated at our institute. In 43 of them (98%, type A: 22 cases, type B: 21 cases), diagnosis was accurate and there were no complications. In one patient with type A dissection, the small intimal flap could not be detected. Emergency operations were performed in the patient with type A and ruptured type B. In type A, operated before cardiac arrest, the operative mortality rate was 20% (4/20). In ruptured type B, the operative mortality rate was 50% (2/4). The result of conservative therapy in the patient with nonruptured type B (17 cases) was satisfactory. The investigation by TEE was carried out without difficulty at the bed side and in the operating room as well, giving precise and rapid information and could be a useful diagnostic mean for acute aortic dissection.

Acute Disease↗
PubMed1991

Emergency surgical intervention of acute aortic dissection with the rapid diagnosis by transesophageal echocardiography.

Forty-five serial patients with acute aortic dissection were examined by transesophageal color Doppler echocardiography (TEE), and the diagnosis was made without aortography. No complications related to TEE occurred. Sufficient information for surgery was immediately obtained at the bedside by the TEE examination. Forty-four of 45 patients (98%) were diagnosed accurately, and 20 emergency operations for patients with type A aortic dissection and six emergency operations for patients with type B aortic dissection were performed. In only one patient, a small intimal flap in the ascending aorta was not detected by TEE. The operative mortality rate was 20% and 50% for types A and B aortic dissections, respectively. As a result of the progress of biplanar TEE technology, an easier and more accurate diagnosis of patients with acute aortic dissection can be achieved. The immediate and accurate diagnosis of acute aortic dissection can be achieved by TEE at the bedside, and treatment strategy can be more precisely determined.

Adult↗
PubMed1990

[Left atrial systolic time intervals: their relations to left atrial preload, afterload and acute left ventricular pressure loading].

Using pulsed Doppler echocardiography, the left atrial pre-ejection period (LAPEP) and left atrial ejection time (LAET) were studied in relation to left atrial loading and acute left ventricular pressure loading conditions in 17 patients with various heart diseases. LAPEP was defined as the time interval from the onset of a right atrial pacing pulse to the upstroke in the atrial contraction phase on the mitral flow velocity pattern; LAET was defined as the duration of left ventricular filling due to atrial contraction. 1. LAPEP did not correlate significantly with mean pulmonary capillary wedge pressure (mPCWP) indicating preload for the left atrium, nor with left ventricular end-diastolic pressure (LVEDP) indicating afterload for the left atrium. There were significant inverse correlations of LAET with mPCWP (r = -0.72) and with LVEDP (r = -0.75). 2. LAPEP, LAET and LAPEP/LAET correlated significantly with the ratio of the peak velocity in the atrial contraction phase and to that in the rapid filling phase (r = -0.62, -0.50 and -0.59, respectively). There was a significant inverse correlation of LAPEP/LAET with the left ventricular ejection fraction (r = -0.62). 3. When left ventricular systolic pressure became elevated by 25% of its basal value at a constant right atrial pacing rate, LAPEP decreased from 110 +/- 21 msec to 103 +/- 22 msec (p less than 0.05), LAET increased from 123 +/- 33 msec to 129 +/- 24 msec and LAPEP/LAET decreased from 0.95 +/- 0.37 to 0.84 +/- 0.32 (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[Evaluation of patency of internal mammary artery grafts: a comparison of two-dimensional Doppler echocardiography with coronary angiography].

To examine the clinical feasibility of color flow mapping Doppler echocardiography (CFM) in diagnosing the patency of internal mammary artery (IMA) grafts, 41 patients who had had coronary bypass surgery were examined by both CFM and coronary angiography (CAG) within one week of the CFM examination. Coronary bypass surgery was performed one to eight months prior to this study, and the average number of bypass grafts was 2.7 +/- 0.7. The patency of the IMA grafts was confirmed in all except one patient by CAG; whereas, the flow in the IMA grafts was clearly visualized in all 22 patients by CFM from the left parasternal echo window. Peak velocities of the IMA graft flow in the 22 patients were 31.7 +/- 12.0 (19-49) cm/sec in diastole and 14.9 +/- 8.5 (5-36) cm/sec in systole. No false positive diagnosis was made in the CFM examination. The sensitivity, specificity, negative predictive value, and positive predictive value of CFM in the diagnosis of IMA graft patency were 55%, 100%, 5.3% and 100% respectively. In conclusion, although the sensitivity of color Doppler still remains relatively low, its specificity in the diagnosis of IMA graft patency is 100%. Thus, color Doppler is expected to be valuable for long-term follow-up of IMA graft patencies.

Adult↗
PubMed1990

[Advantages of transesophageal color Doppler echocardiography in the diagnosis and surgical treatment of cardiac masses].

To determine the clinical advantages of transesophageal color Doppler echocardiography (TEE) for imaging cardiac tumors and left atrial thrombi, 24 cases with intra- or extracardiac masses were examined by transthoracic color Doppler echocardiography (TTE) and TEE before and after cardiac surgery. Five with left atrial myxomas, two with lung tumors, five with mediastinal tumors and 12 with mitral stenosis coexisting left atrial thrombi were included in this study. The echocardiographic findings of the cardiac masses were compared with the surgical findings in all cases. In all of the five cases with left atrial myxomas, the tumors were detected. However, the sites of attachment and a stalk in three cases were not observed by TTE. TEE clearly imaged the left atrial myxomas, and evaluated the size and shape of the tumors, the sites of their attachment and a stalk arising from the interatrial septum, and mobility in four cases, except for one in which there was a broad attachment to the endocardium. Mitral regurgitation was detected in only two cases using the color Doppler mode of TTE, but in all cases using TEE. Both techniques failed to recognize tissue characterization. Among seven cases with secondary cardiac tumors or mediastinal tumors, extracardiac masses were detected in five; however, an intracardiac tumor attached to the interatrial septum and an extracardiac tumor extending to the superior vena cava and an upper part of the right atrium could not be imaged using TTE. TEE detected all tumors at all sites in the heart and vessels, and estimates of their extents were in accord with the operative findings in 17 of 18 sites. One exceptional case had a tumor which extended to the right ventricle. Neither technique could detect infiltration of the heart which was present in five of the seven cases. Multiple left atrial thrombi were observed in eight of 12 cases, resulting in 21 thrombi and they were diagnosed by TEE in six of 12 cases. Thrombi, when attached to the left atrial posterior or inferior walls, were easily detected in four of five cases, but were not identified in four of six and in eight of nine cases at the lateral wall or in the left atrial appendage by TTE. However, TEE detected all thrombi in every site in the left atrium and left atrial appendage in 11 of 12 cases. TEE was thus superior to TTE in detecting cardiac masses, recognizing abnormal flow and estimating anatomical relationship between tumors or thrombi and cardiac structures.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗