Yuji Yokote

Ventricular Afterload and Ventricular Work in Fontan Circulation

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 (P0.01), 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, -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. (Circulation. 2002;105:2885-2892.)

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 M 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 < 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 < 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.

Vasopressin in the treatment of vasodilatory shock in children

Abstract  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.

Ventricular energetics in Fontan circulation: Evaluation with a theoretical model

Abstract Background : Both pulmonary and systemic circulation must be maintained by a single pump in Fontan circulation. This unique property of Fontan circulation may be related to decreased exercise tolerance or increased instantaneous postoperative mortality rate, often observed in patients with this circulation. To better understand Fontan physiology, the present study theoretically investigated cardiac performance of Fontan circulation by using ventricular–vascular coupling framework analysis.

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.

Usefulness of Transesophageal Echocardiography in Detecting Changes in Flow Dynamics Responsible for Malperfusion Phenomena Observed During Surgery of Aortic Dissection

Intraoperative transesophageal echocardiography (TEE) was performed in order to study the flow dynamics in the descending aorta during surgery of aortic dissection Stanford A. TEE was seen to be a sensitive and accurate method to promptly detect severe decrease in retrograde pump flow and to clarify some of the mechanisms that can result in malperfusion during cardiopulmonary bypass.

Future Technical Prospects in Biplane Transesophageal Echocardiography: Use of Adult and Pediatric Biplane Matrix Probes

This study evaluates the feasibility of the combined use of an adult matrix probe with a real‐time biplane imaging system, and also describes the performance of a newly developed pediatric matrix probe. (ECHOCARDIOGRAPHY, Volume 8, November 1991)

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

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.

Development and clinical application of minimally invasive cardiac surgery using percutaneous cardiopulmonary support

OBJECTIVES Optimal cardiopulmonary support during minimally invasive cardiac surgery remains controversial. We developed cardiopulmonary bypass for minimally invasive cardiac surgery using percutaneous peripheral cannulation. METHODS Subjects were 34 patients (age: 58 +/- 13 years; range: 17-73) undergoing minimally invasive cardiac surgery using percutaneous cardiopulmonary support between June 1997 and March 1999. Procedures included atrial septal defect closure (n = 14), partial atrioventricular septal defect closure (n = 1), mitral valve replacement (n = 8), mitral valve repair (n = 3), aortic valve replacement (n = 6), coronary artery bypass grafting (n = 1), and right atrial myxoma extirpation (n = 1). Bicaval venous drainage from the right internal jugular vein and the femoral vein and arterial return to the femoral artery were instituted by percutaneous cannulation. Venous drainage was implemented by negative pressure (-20 to -40 mmHg) and arterial return was by conventional roller pump. All procedures were conducted through a skin incision 8 +/- 1 cm, from 6 to 10 cm and partial sternotomy. Aortic cross clamping and cardioplegic solution were administered in the surgical field. RESULTS The operation lasted 224 +/- 45 min., cardiopulmonary bypass 104 +/- 32 min., and aortic clamping 77 +/- 23 min.. No deaths occurred. One patient with residual atrial septal defect required reoperation through the same skin incision. Only 1 patient required homologous blood transfusion. The average postoperative hospital stay was 15 +/- 5 days. CONCLUSIONS Minimally invasive cardiac surgery using percutaneous cardiopulmonary support is safe and an excellent option for selected patients affected by single valve lesion, simple cardiac anomalies, and coronary artery bypass grafting.

Clinical effects of ventricular assist system in end-stage cardiac failure. Advantages of left ventricular blood drainage for recovery from cardiac dysfunction.

OBJECTIVES Heart transplantation is extremely limited currently in Japan. As a consequence ventricular assist system implantation is employed the patient falls into end-stage cardiogenic shock. This preliminary report describes our initial clinical experience with use of 2 kinds of ventricular assist system for 13 Japanese patients. METHODS 7 patients were supported by a left ventricular assist system with blood drainage from the left atrium (LA drainage Group) using a Toyobo ventricular assist system, while another 6 patients were supported by a left ventricular assist system with blood drainage from the left ventricle (LV drainage Group) using the Toyobo ventricular assist system (1 patient) or TCI-LVAS (5 patients). RESULTS The average duration of ventricular assist system support in the LV drainage Group was 112 days including two on-going patients (now at 39 days and 241 days) and in the LA drainage Group was 49 days. The average left ventricular ejection fraction at 3 weeks after ventricular assist system implantation was improved from 12.3 to 54% using the TCI-LVAS and from 14 to 33% using the Toyobo ventricular assist system with drainage from the left ventricle. However, this was decreased from 20 to 10% using the Toyobo ventricular assist system with drainage from the left atrium. The ventricular assist system was explanted in 4 patients (31%) with recovery of cardiac dysfunction and 3 were long survivors. The 2 on-going patients are awaiting heart transplantation. Thus the current survival rate overall is 38%. The survival rate (67%) is excellent in the LV drainage Group including 2 long survivors after explantation. CONCLUSION Ventricular assist system support with drainage from the left ventricle seems to be more advantageous for cardiac functional recovery than from the left atrium for end-stage heart failure.