Hideaki Senzaki

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 · s · cm−5 · 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.

stenosis of a Reconstructed Aorta caused a paradoxical Diastolic pressure Gradient After norwood Operation

An infant with hypoplastic left heart syndrome showed paroxysmal episodes of bradycardia, hypotension, and hypoxemia upon crying after modified Norwood operation. Echocardiography showed decreased right ventricular ejection with grade III tricuspid regurgitation, a markedly enlarged aortic arch, and accelerated blood flow distal to the enlarged aorta. Aortography demonstrated an aneurysmal neo-aorta with an apple-shaped appearance. The pressure measurements revealed intriguing aortic hemodynamics: the diastolic pressure of the ascending aorta was lower than that of the descending aorta (42 mmHg vs. 52 mmHg) despite no systolic pressure gradient. Markedly reduced compliance in the ascending aorta relative to that in the descending aorta, which was suggested by the difference in time constant of aortic pressure decay, may explain this hemodynamics. Impaired coronary circulation caused by lowered diastolic pressure in ascending aorta was indicated by reduced subendocardial viability ratio, and may account for her symptom and lowered ventricular ejection. The patients condition was indeed significantly improved by surgical correction of the aortic shape. This case highlights the importance of aortic shape and properties after Norwood operation.

Clinical Evaluation of the Hemodynamic Effects of the High-Flow Nasal Cannula Therapy on the Fontan Circulation.

High-flow nasal cannula (HFNC) therapy supports respiratory effort with a minimal elevation in airway pressure. We examined hemodynamic effects of HFNC therapy in a 10-year-old girl with Fontan circulation, in which positive airway pressure has deleterious hemodynamic effects. The HFNC therapy at 30 L/min improved oxygenation without an increase in central venous pressure. It also reduced heart rate, and systemic and pulmonary vascular resistance, and increased cardiac output. In addition, the HFNC therapy improved the cerebral circulation measured by near-infrared spectroscopy. Thus, HFNC therapy may be a potentially useful noninvasive ventilation modality, particularly for patients with Fontan circulation.

Stent Implantation for Effective Treatment of Refractory Chylothorax due to Superior Vena Cava Obstruction as a Complication of Congenital Cardiac Surgery

Chylothorax is a serious complication of congenital cardiac surgery and is significantly associated with increased morbidity and mortality. Central venous obstruction, which is often related to the insertion of central venous catheters for postoperative management, is known to be an important risk factor for treatment failure and mortality associated with this condition. We present the case of a 6-month-old girl with refractory chylothorax after surgical repair of tetralogy of Fallot. The chylous drainage continued for more than 2 months despite maximal conservative therapy (water restriction, total parenteral nutrition, and infusion of somatostatin and steroid) and surgical ligation of the thoracic duct. Subsequently, we observed stenosis of the superior vena cava (SVC) caused by large thrombi possibly associated with the prolonged use of central venous catheter placed in the internal jugular vein. Because transcatheter balloon dilation failed to relieve the stenosis, we performed stent implantation for the SVC and innominate vein. After the procedure, chylous drainage dramatically reduced, and the patient was discharged from the hospital. In conclusion, central venous obstruction due to thrombosis should be routinely examined when chylothorax is diagnosed and is resistant to conservative therapy after congenital heart surgery. Stent implantation can effectively relieve the venous obstruction and thus be a life-saving treatment option for this difficult condition.

Congenital Aortic Stenosis in Children

Congenital aortic stenosis (AS) is caused by abnormal morphological development of the aortic valve. [1, 2] Valvular abnormalities may be accompanied by supraor subvalvular stenosis. The embryogenic process that forms aortic valves begins approxi‐ mately 31–32 days of gestation. Cavity formation in the basal portion of the truncus arteriosus is a key process in the development of the leaflet and sinus of Valsalva, which are important components of the aortic valve. Therefore, incomplete formation of the cavity causes various morphological abnormalities of the aortic valve, including bicuspid valve with or without commissural fusion, tricuspid valve with commissural fusion, monocuspid valve, and myxomatoid leaflet valve (dysplastic valve). The most frequent type of congenital AS is a bicuspid aortic valve, [3] accounting for approxi‐ mately 90% of AS cases.