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Biomedical subjects

Yuji Yokote

Publications and source records attributed to Yuji Yokote.

At least 19 recordsLinked to original sources
PubMed2006

Cardiac rest and reserve function in patients with Fontan circulation.

OBJECTIVES: In the present study, we systematically tested cardiac rest and reserve function in patients with Fontan physiology to check for inherent limitations of this circulation. BACKGROUND: Details of the mechanisms of cardiac performance that could account for adverse outcome after Fontan surgery are not well understood. METHODS: The subjects were 17 Fontan patients with good functional status (Fontan group) and 20 patients with normal two-ventricle circulation (control group). We examined baseline ventricular contractility, diastolic function, and loading factors, and examined changes in those parameters in response to increased heart rate (HR) due to atrial pacing and in response to beta-adrenergic stimulation, using ventricular pressure-area relationships during preload reduction. RESULTS: At baseline, the Fontan patients exhibited minimal abnormality of cardiac properties, but the significant increase in afterload resulted in decreased cardiac index. In addition, Fontan circulation was associated with limited inotropic response and worsening of diastolic filling with increased HR, leading to decreased systolic pressure and elevation of central venous pressure at higher HRs (p < 0.05 vs. control). Furthermore, beta-adrenergic reserve was markedly decreased in the Fontan group, compared with controls, owing to limited preload reserve rather than limited contractile reserve. CONCLUSIONS: Because normal ventricular-vascular interaction and augmentation of cardiac performance during increased HR and adrenergic stimulation are important for maintaining cardiac output and exercise capacity, the present results may have important implications for the mechanisms underlying adverse outcome after Fontan surgery. Thus, improvement of long-term prognosis of patients after Fontan surgery requires the development of medical interventions that can overcome such limitations inherent in Fontan circulation.

Child↗
PubMed2006

[Successful salvage of a patient with cardiac arrest caused by multiple pulmonary emboli and lung abscesses due to infective endocarditis of the tricuspid valve: a case report].

A 28-year-old female developed infective endocarditis in the tricuspid valve and multiple lung abscesses due to septic pulmonary emboli early after intensive therapy for ulcerative colitis. The pathogen was methicillin-resistant Staphylococcus aureus. Usual antibiotic agents and linezolid were administered. Three weeks later, she fell into cardiopulmonary arrest due to further pulmonary emboli and required mechanical circulatory assist. Fatal brain damage was suggested at first. Two days later, she fully regained consciousness and underwent tricuspid valve replacement using mechanical valve and extirpation of septic pulmonary embolus. Mechanical circulatory assist was discontinued on the next day. After strenuous administration of linezolid and other drugs for 9 weeks, she was discharged from hospital on foot. We believe that early surgical intervention should be considered in patients with infective endocarditis in the right heart and subsequent septic pulmonary emboli. Linezolid was very useful in this patient.

Acetamides↗
PubMed2005

Arterial hemodynamics in patients after Kawasaki disease.

BACKGROUND: Histopathological findings in the acute stage of Kawasaki disease (KD) indicate widespread vascular inflammation that involves not only coronary arteries but also systemic arteries. This may cause changes in systemic arterial wall properties after KD, which could have adverse effects on arterial hemodynamics (an important predictor of cardiovascular morbidity and mortality). METHODS AND RESULTS: Systemic arterial hemodynamics were investigated by measuring aortic input impedance during cardiac catheterization in 42 KD patients who had developed coronary artery lesions (CALs) in the acute stage of KD. The KD patients were subdivided into 2 groups according to the angiographic findings (group 1A, 26 patients with persistent CALs; group 1B, 16 patients with regressed CALs), and results were compared with those of 36 referents (group 2). Compared with referents, characteristic impedance was significantly higher for KD patients (137.0+/-5.1, 125.7+/-8.2, and 97.9+/-4.1 dyne x s x cm(-5) x m2 for group 1A, group 1B, and group 2, respectively), and total peripheral arterial compliance indexed to age-specific values was significantly lower for KD patients (group 1A 72.9+/-4.2% of normal; group 1B 70.6+/-5.9% of normal; group 2 97.7+/-4.0% of normal; for both variables, P<0.05 for each KD group versus group 2; P=NS between KD groups), which suggests that both central and peripheral arterial wall stiffness increase after KD regardless of persistence of CALs. Also, indices of arterial wave reflection (reflection coefficient, reflection factor, and augmentation index) were all significantly higher in KD patients than in referents (P<0.05), with the result that the aortic pressure waveforms of the present KD patients resembled those generally observed in the elderly. In addition, levels of circulating markers of endothelial dysfunction (ACE and von Willebrand factor) were associated with increased vascular stiffening in KD patients but not in referents. CONCLUSIONS: These results indicating abnormal arterial hemodynamics after KD highlight the importance of regular monitoring of the systemic arterial bed and potentially relevant cardiovascular events in long-term follow-up of KD.

Adolescent↗
PubMed2005

Impact of postoperative blood pressure control on regression of left ventricular mass following valve replacement for aortic stenosis.

OBJECTIVE: Considerable left ventricular (LV) hypertrophy sometimes remains after aortic valve replacement (AVR) for aortic stenosis. For this issue, most previous studies have focused solely on transprosthetic pressure gradient, although true problem is not the pressure gradient itself but an elevated LV pressure. This study investigated the impact of blood pressure on postoperative LV mass regression, which had been overlooked in previous studies. METHODS: Seventy-nine adult patients with pure aortic stenosis who were treated with AVR using bileaflet mechanical valves underwent echocardiography before surgery, around 6 months later ('early'), and 2-3 years later (31.7+/-14.7 months, 'late'). Patients were divided into two groups whether postoperative systolic blood pressure was below (n=47; N group) or above 130 mmHg (n=32; H group) following recommendation of WHO-ISH and JNC 7th report. Preoperative LV mass (g/m2) did not differ significantly (232+/-80 vs. 243+/-76, P=0.91). RESULTS: LV mass became significantly smaller and regression was significantly more effective in N group than in H group both at 'early' (145+/-43 vs. 180+/-54, regression against preoperative value 34.6+/-19.1 vs. 19.9+/-26.6%, P=0.007) and 'late' (132+/-41 vs. 178+/-51, regression 41.1+/-16.0 vs. 21.0+/-27.0%, P<0.001) evaluations. Regression between 'early' and 'late' evaluations was significant only in N group (P=0.012). The LV mass index returned to the normal range at 'late' evaluation in 52.1% of N group and 12.5% of H group patients (P<0.001), and 25 out of 29 patients without residual LV hypertrophy were N group patients. Multivariate analyses revealed that preoperative LV mass index (P<0.001) and postoperative systolic blood pressure (P=0.007) showed significant influence on postoperative LV mass index, and postoperative systolic blood pressure alone significantly (P<0.001) influenced the regression ratio of the LV mass against the preoperative value. No prosthesis related variables (size, orifice area index, pressure gradient) had significant influence. CONCLUSIONS: For LV mass regression after AVR, postoperative blood pressure appeared to be more important than prosthesis selection. Controlling the systolic blood pressure below 130 mmHg was beneficial, which coincided with recommendation of WHO-ISH and JNC 7th report despite the pressure drop due to prosthesis in the aortic position.

Aged↗
PubMed2005

Usefulness of selective contrast echocardiography and selective scintigraphy for the evaluation of pulmonary arteriovenous fistula in a patient with systemic arterial supply to a normal lung.

To determine a surgical procedure for the correction of a systemic arterial supply to a normal lung, it is important to evaluate whether the patient has a pulmonary arteriovenous fistula. In this article, the authors report for the first time a patient in which selective contrast echocardiography and selective perfusion scintigraphy from an abnormal artery clearly demonstrated and quantified the pulmonary arteriovenous fistula. The authors believe that these methods are useful in determining the appropriate operative procedure for this condition.

Aorta, Thoracic↗
PubMed2005

Vasopressin in the treatment of vasodilatory shock in children.

BACKGROUND: Many recent studies suggest that vasopressin deficiency is an important cause of catecholamine-resistant hypotension with vasodilation in adults, but little is known about vasopressin deficiency in children. METHODS: To clarify the usefulness of vasopressin administration in pediatric cathecolamine-resistant hypotension with preserved ventricular contractility, urinary output and blood pressure response to vasopressin were retrospectively analyzed in 12 consecutive patients (15 instances) who were treated with vasopressin. The causes of vasodilation were central nervous system disturbance (n = 5), side-effect of drug (n = 5), and infection (n = 5). Plasma vasopressin concentration was measured six times before vasopressin administration and five times during vasopressin administration. RESULTS: Patients were divided into four groups according to their response to vasopressin administration. In group 1 (n = 5), urinary output increased to > 3 mL/kg per h within 3 h after vasopressin administration. In group 2 (n = 4), urinary output increased to > 3 mL/kg per h from 3 to 5 h after vasopressin administration. In group 3 (n = 4), urinary output did not increase to > 3 mL/kg per min within 5 h after vasopressin administration, but systolic blood pressure increased to > 120% of the level at the time of vasopressin administration. All remaining patients were classified into group 4 (n = 3). Plasma vasopressin concentration were low considering the markedly hypotensive state in all six instances. Plasma vasopressin concentration during vasopressin administration were significantly increased compared with before administration (P < 0.05). No apparent side-effects were observed in this series. CONCLUSION: Vasopressin deficiency may occur in catecholamine-resistant hypotension of pediatric patients due to various causes including central nervous system disturbance, drug induced hypotension and sepsis. Small doses of vasopressin administration seems to be very effective in such conditions by increasing blood pressure and urinary output.

Adolescent↗
PubMed2005

[Coronary artery bypass grafting in patients undergoing chronic hemodialysis: importance of wound healing and hypoproteinemia].

OBJECTIVES: Outcome of coronary artery bypass grafting (CABG) in patients undergoing chronic hemodialysis was studied. METHODS: Between January 1996 and August 2004, 49 consecutive hemodialysis patients [38 males and 11 females, mean age 60.0 years (range 47-74 years)] underwent CABG using cardiopulmonary bypass. Duration of hemodialysis was 5.2 years (range 1 month-21 years), and 32 patients were diabetics. Surgery was conducted on the emergency/urgency basis in 12 patients, and intraaortic balloon pumping was placed in 7. Left ventricular ejection fraction was 57.7 +/- 16.3% (range 27-84%). Nine patients underwent concomitant valve surgery. CABG was performed under hypothermic cardiopulmonary bypass and ventricular fibrillation except in one patient, and intraoperative hemodialysis was also performed. Continuous hemodiafiltration was used in the early period after surgery. RESULTS: Number of bypass grafts was 3.0 +/- 1.0 (range 1-6), and the unilateral internal thoracic artery was used in 29 patients. Operation time, cardiopulmonary bypass time, and aorta clamp time were 313 +/- 87, 145 +/- 63, and 49 +/- 43 min, respectively. Diffuse pericardial adhesion was present in five patients. Severely atheromatous ascending aorta precluded manipulation in seven patients. Although the 30-day mortality was 2.0% (one case), all in-hospital mortality over 9 months was 14.3% (seven cases). The morbid events were mediastinitis in seven cases, reexploration for hemorrhage in seven, pneumonia in two, abdominal complication in three, and stroke in one. Delayed onset mediastinitis was common. Risk factors for death were mediastinitis and serum albumin levels < 3.5 g/dl (both p < 0.05), both of which were wound healing-related factors. CONCLUSIONS: CABG in hemodialysis patients carries a high risk. Patients with hypoalbuminemia appear to require special consideration.

Aged↗
PubMed2004

[Aortic root replacement using an allograft for active infective endocarditis with periannular abscess: single center experience].

OBJECTIVES: Results of aortic root replacement using an allograft for active infective endocarditis in the aortic position and periannular abscess were studied. METHODS: Aortic root replacement using a cryopreserved aortic allograft was performed 13 times in 12 patients (9 men, 3 women, mean age 52.8 years) at Saitama Medical School. Allografts were obtained from the Tokyo University Tissue Bank. Infection affected the prosthetic valve in 6 patients and the native valve in 7. Causative organisms were Staphylococci in 7 patients, Streptococci in 2, and unknown in 4. New York Heart Association functional class was II in 2 patients, III in 3, and IV in 8. Six patients required inotropic support. Four were mechanically ventilated. Two were in a state of profound shock. Four had multiple organ failure. Surgery was conducted under hypothermic cardiopulmonary bypass and cardioplegic arrest. Allograft was sewn into place by monofilament continuous sutures. Carrel patch technique was used for coronary artery reconstruction. Five patients underwent concomitant procedures (replacement of the ascending aorta in 2 patients, coronary artery bypass grafting in 1, mitral valve repair in 1, pulmonary artery reconstruction in 1). RESULTS: Duration of surgery, cardiopulmonary bypass, and aortic clamping were 507 +/- 154, 307 +/- 111, and 189 +/- 49 min, respectively. Two patients required intraaortic balloon pumping, and one required percutaneous cardiopulmonary support. Two patients in a state of shock died(hospital mortality: 15.4%). Duration of mechanical ventilation was 2.9 +/- 3.7 days. Intensive care unit stay was 4.6 +/- 5.5 days, and hospital stay was 61 +/- 26 days. One patient died of cancer 18 months later. One patient required reoperation 11 months later. Including operative death cases, cumulative survival at 2 years was 66.5% and freedom from cardiac events was 72.7%. CONCLUSIONS: Aortic root replacement with an allograft yielded acceptable clinical results.

Abscess↗
PubMed2003

Dilated cardiomyopathy in a 3-year-old girl with a terminal deletion, 46,XX,del(3)(q27-qter), of the long arm of chromosome 3.

UNLABELLED: We report a case in which a 3-year-old girl with terminal deletion of the long arm of chromosome 3 had dilated cardiomyopathy, a complication that has not previously been reported in association with this chromosome abnormality. In addition to cardiomyopathy, she had intrauterine growth retardation, small eyes and mouth, a broad nose, thin lips, low-set ears, a short neck and overlapping second toes. CONCLUSION: due to the paucity of reported cases of 3q deletion, and the clinical variability of such cases, identification of a distinct 3q phenotype (including cardiac complications) remains elusive.

Cardiomyopathy, Dilated↗
PubMed2003

Plasminogen activator inhibitor-1 in patients with Kawasaki disease: diagnostic value for the prediction of coronary artery lesion and implication for a new mode of therapy.

Kawasaki disease (KD) in children takes the form of acute systemic vasculitis, which causes coronary artery dilation and aneurysm formation in 10% to 15% of the patients. We have recently shown that matrix metalloproteinases (MMPs) are intimately involved in coronary arterial wall destruction and the resultant formation of coronary artery lesions (CALs) in this disease. Plasminogen activators (PAs) are known to be a major pathway of MMP activation, and this suggests that their inhibitor, plasminogen activator inhibitor-1 (PAI-1), also plays important roles in the development of CALs in KD. The present study was conducted to test the hypothesis that circulating levels of PAI-I are related to CAL formation in KD. Plasma levels of PAI-1 were measured by enzyme-linked immunoassay in 37 KD patients without CALs (group 1) and 7 KD patients with CALs (group 2). Blood samples were obtained before and after i.v. gammaglobulin therapy (IVGG), and in the convalescent stage. Levels of PAI-1 were significantly higher in KD patients before IVGG than in 18 age-matched healthy control subjects (p < 0.01). More importantly, both pre-IVGG and post-IVGG levels of PAI-1 were significantly higher in group 2 than in group 1 (p < 0.01). Furthermore, PAI-1 levels of 9 patients from group 1 who showed pre-IVGG PAI-1 levels higher than the minimum PAI-1 level in group 2 significantly decreased after IVGG, whereas PAI-1 levels of group 2 patients remained persistently elevated, further suggesting a close association between PAI-1 and CAL development in KD. Thus, PAI-1 may be useful as a predictive marker for CAL development in KD. Studies of the effects of PA inhibition on coronary outcome may provide evidence that PA is a viable therapeutic target for the prevention of KD-related CALs.

Coronary Vessels↗
PubMed2003

Combined coronary artery bypass grafting and abdominal aortic aneurysm repair.

The purpose of this paper was to assess the results and feasibility of simultaneous coronary artery bypass grafting and abdominal aortic aneurysm repair. Twenty nine patients with a mean age of 65 years underwent simultaneous coronary artery bypass grafting and abdominal aortic aneurysm repair between June 1990 and March 2002. All patients had significant coronary artery disease and were considered as indicated for coronary artery bypass grafting. This was performed first in 28 patients and simultaneously with abdominal aortic aneurysm repair in one, with a mean number of grafts of 2.5, a mean aortic cross-clamp time of 40 minutes, and a mean bypass time of 115 minutes. Eight straight and 21 bifurcated grafts were employed. The total operating time averaged 400 minutes. The median postoperative hospital stay was 18 days. One patient died of stroke and mediastinitis, for a mortality rate of 3.5%. This experience suggests that combined coronary artery bypass grafting and abdominal aortic aneurysm repair is both safe and effective.

Adult↗
PubMed2003

Noncardioplegic surgery for ischemic mitral regurgitation.

Twenty-seven consecutive patients underwent surgery for ischemic mitral regurgitation (MR): papillary muscle rupture (1), papillary muscle dysfunction (11) and annular dilatation (15). The grade of MR was moderate or severe, and the ejection fraction (EF) was less than 30% in 8 patients (mean, 43%). Three cases were reoperation and 3 were emergencies. Under ventricular fibrillation (VF) and intermittent aortic cross-clamping at moderate hypothermia, coronary artery bypass grafting (CABG) was performed first, followed by the mitral procedure through a right-sided left atriotomy (repair 21, replacement 6) performed under VF with the heart perfused through the native coronary arteries and CABG grafts. Concomitant procedures were CABG (23), Dor's procedure (5), and tricuspid annuloplasty (3). In one reoperative case with cardiogenic shock, CABG was impossible because of dense adhesions and the patient died just after surgery (hospital mortality, 3.7%). Five patients required intra-aortic balloon pump (IABP) support intraoperatively, but none required prolonged (> or =7 days) inotropic support or IABP use, although the serum concentrations of creatine kinase and its myocardial fraction were elevated remarkably. Other morbid events were refractory ventricular arrhythmia in one case and stroke in another. Median duration of mechanical ventilation and intensive care unit stay was 8 h and 3 days, respectively. Mean EF at hospital discharge was 48%. The extended period of VF was not associated with unfavorable clinical outcomes. Noncardioplegic surgery for ischemic MR was carried out with acceptable mortality and morbidity, and can be a good alternative, especially when clamping the aorta is undesirable.

Aged↗
PubMed2003

Mid-term results of aortoplasty for dilated ascending aorta associated with aortic valve disease.

BACKGROUND: Dilatation of the ascending aorta concomitant with aortic valve disease is occasionally associated with progressive enlargement of the ascending aorta or acute aortic dissection (AAD). However, surgical procedure of choice for the aorta and its indication are controversial. PATIENTS AND METHODS: From July 1995 to August 2001, 10 patients with a moderately dilated ascending aorta (mean diameter, 52+/-4.8 mm) underwent concurrent aortic valve replacement (AVR) and aortoplasty. The aortic valve was bicuspid in eight patients. To tailor the ascending aorta 30-35 mm in diameter, the aortic wall was partially resected along the aortotomy, and the aorta was directly closed. RESULTS: Operation time and most of other perioperative variables were comparable to those of patients who underwent isolated AVR. The aortic diameter was reduced to 36.1+/-4.1 mm. Nine patients survived to hospital discharge uneventfully, but one patient developed disruption of the suture line in the aorta and died. During follow-up, no patient suffered AAD but redilatation was observed in one patient. In the two problematic patients, the ascending aorta was larger than 55 mm, and its media was histologically abnormal. CONCLUSION: In patients with dilated ascending aorta less than 55 mm in diameter, aortoplasty can be a procedure of choice. However, a prosthetic graft replacement is recommended when the diameter of the ascending aorta is larger than 55 mm.

Adult↗
PubMed2002

Ventricular afterload and ventricular work in fontan circulation: comparison with normal two-ventricle circulation and single-ventricle circulation with blalock-taussig shunts.

BACKGROUND: Recent studies have indicated that there are inherent limitations associated with Fontan physiology. However, there have been no quantitative analyses of the effects of right heart bypass on ventricular afterload, hydraulic power, and resultant overall hemodynamics. Methods and Results- During routine cardiac catheterization, aortic impedance and ventricular hydraulic power were determined, both at rest and under increased ventricular work induced by dobutamine, in 17 patients with Fontan circulation, 15 patients with a single ventricle whose pulmonary circulation was maintained only by Blalock-Taussig shunts, and 13 patients who had normal 2-ventricle circulation. Both vascular resistance (nonpulsatile load on the ventricle) and pulsatile components of ventricular afterload (represented by low-frequency impedance) were significantly higher in the Fontan group than in the other groups (P<0.01), and this was associated with decreased cardiac output in the Fontan patients. In addition, hydraulic power cost per unit forward flow was 40% lower in the 2-ventricle circulation than in the single-ventricle circulation, suggesting lower ventricular efficiency in single-ventricle circulation attributable to the lack of a pulmonary ventricle. Furthermore, in the Fontan group, beta-adrenergic reserve was markedly decreased because of a limited preload reserve. CONCLUSIONS: Fontan physiology is associated with disadvantageous ventricular power and afterload profiles and has limited ventricular reserve capacity. Thus, to improve the long-term prognosis of patients after Fontan surgery, future research should be conducted into medical interventions that can overcome these limitations inherent in Fontan circulation.

Adrenergic beta-Agonists↗
PubMed2002

Allograft pulmonary artery root replacement for refractory isolated pulmonic valve endocarditis.

A 45-year-old diabetic woman was subjected to percutaneous cardiopulmonary support for a life-threatening pulmonary embolism. One month later, she developed isolated pulmonic valve endocarditis. The causative organism was methicillin-resistant Staphylococcus aureus. Because of the uncontrollable infection and residual pulmonary hypertension, she underwent pulmonary artery root replacement with a cryopreserved pulmonary allograft. The postoperative course was very good. In this case, allograft implantation with a full root played a very important role because this method permitted thorough resection of the infected tissues and reconstruction which is highly resistant to infection.

Angiography↗